Steam Cured Self-Consolidating Concrete and the Effects of Limestone Filler
by
Mohammad A. Aqel M.Sc., PMP, LEED AP BD+C, EIT
A thesis submitted in conformity with the requirements for the degree of
Doctor of Philosophy Department of Civil Engineering
University of Toronto
© Copyright by Mohammad A. Aqel (2016)
ii
Steam Cured Self-Consolidating Concrete and the Effects of
Limestone Filler
Mohammad A. Aqel
Doctor of Philosophy
Civil Engineering Department
University of Toronto
2016
Abstract
The purpose of this thesis is to determine the effect and the mechanisms associated with
replacing 15% of the cement by limestone filler on the mechanical properties and durability
performance of self-consolidating concrete designed and cured for precast/prestressed
applications. This study investigates the role of limestone filler on the hydration kinetics,
mechanical properties (12 hours to 300 days), microstructural and durability performance
(rapid chloride permeability, linear shrinkage, sulfate resistance, freeze-thaw resistance
and salt scaling resistance) of various self-consolidating concrete mix designs containing
5% silica fume and steam cured at a maximum holding temperature of 55°C. This research
also examines the resistance to delayed ettringite formation when the concrete is steam
cured at 70°C and 82°C and its secondary consequences on the freeze-thaw resistance. The
effect of several experimental variables related to the concrete mix design and also the
curing conditions are examined, namely: limestone filler fineness, limestone filler content,
cement type, steam curing duration and steam curing temperature.
In general, the results reveal that self-consolidating concrete containing 15% limestone
filler, steam cured at 55°C, 70°C and 82°C, exhibited similar or superior mechanical and
transport properties as well as long term durability performance compared to similar
concrete without limestone filler. When the concrete is steam cured at 55°C, the chemical
reactivity of limestone filler has an important role in enhancing the mechanical properties
at 16 hours (compared to the concrete without limestone filler) and compensating for the
dilution effect at 28 days. Although, at 300 days, the expansion of all concrete mixes are
iii
below 0.05%, the corresponding freeze-thaw durability factors vary widely and are
controlled by the steam curing temperature and the chemical composition of the cement.
Overall, the material properties indicate that the use of 15% limestone filler as cement
replacement is a viable option for the precast/prestressed concrete applications, and in
addition, would also have economic and environmental benefits.
iv
Acknowledgements
I would like to take this opportunity to express my special appreciation and thanks to my
supervisor Prof. Daman K. Panesar for her continued support, guidance and
encouragement. I would like to acknowledge the support and guidance provided by my
PhD examination committee members Prof. Doug Hooton, Prof. Karl Peterson and Prof.
Kim Pressnail. I sincerely appreciate Prof. Kamal Khayat for his support as the external
examiner of my thesis.
I would like to thank my parents Dr. Abdullah Aqel and Eman Othman and my brothers
and sister for their continuous support and prayers. Although, I was away from them for
more than four years, their support was felt as they were living with me.
Finally, a special thanks to my family. Words cannot express how grateful I am to my wife
Luma and my sons Yousef and Zain for their support throughout my PhD study. I love you
all.
v
List of Acronyms
AASHTO American Association of State Highway and Transportation Officials
AEA Air-entraining Admixture
ACI American Concrete Institute
AFm Alumina, Ferric Oxide, Mono-sulfate
ASTM American Society for Testing and Materials
BF Brucite Filler
COV Coefficient of Variation
CPCI Canadian Precast/Prestressed Concrete Institute
CSA Canadian Standard Association
CSH Calcium Silicate Hydrate
DEF Delayed Ettringite Formation
DOT Department of Transportation
DTA Differential Thermal Analysis
GU General Use (CSA A3000)
GUL General Use with Limestone (CSA A3000)
HE High Early Strength
HRWR High-range Water Reducer
HS High Sulfate Resistance
ITZ Interfacial Transition Zone
LF Limestone Filler
LOI Loss on Ignition
MK Metakaolin
MIP Mercury Intrusion Porosimetry
MTO Ministry of Transportation - Ontario
OPSS Ontario Provincial Standard Specification
PCI Precast/Prestressed Concrete Institute
PLC Portland-Limestone Cement
RCPT Rapid Chloride Permeability Test
RH Relative Humidity
S/A Sand-to-total Aggregate Ratio
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SCC Self-Consolidating Concrete
SCM Supplementary Cementitious Materials
SEM Scanning Electron Microscopy
SF Silica Fume
TG Thermal Gravimetric Analysis
UPV Ultrasonic Pulse Velocity
VSI Visual Stability Index
W/C Water-to-cement Ratio
wt% Percentage by Weight
vii
Table of Contents
Chapter 1 - Thesis Overview .............................................................................................. 1
1.1. Introduction .......................................................................................................... 1
1.2. Research Objectives ............................................................................................. 3
1.3. Research Outline .................................................................................................. 4
1.4. Background .......................................................................................................... 7
1.4.1. Limestone as a Cement Replacement ........................................................... 7
1.4.2. Energy Saving by Using Limestone ............................................................. 8
1.4.3. Economic Evaluation of Using Self-Consolidating Concrete in
Precast/Prestressed Applications ................................................................................ 9
1.4.4. Effect of Steam Curing Temperature .......................................................... 10
1.5. References .......................................................................................................... 14
Chapter 2 - Physical and Chemical Effects of Limestone Filler on Steam Cured Cement
Paste, Mortar and Concrete ............................................................................................... 23
2.1. Introduction ........................................................................................................ 23
2.2. Experimental Program........................................................................................ 26
2.2.1. Materials ..................................................................................................... 26
2.2.2. Mix Designs ................................................................................................ 28
2.2.3. Curing Regime ............................................................................................ 29
2.2.4. Test Methods ............................................................................................... 30
2.3. Results and Discussion ....................................................................................... 32
2.3.1. Heat of Hydration ....................................................................................... 32
2.3.2. Thermal Analysis ........................................................................................ 34
2.3.3. X-Ray Diffraction ....................................................................................... 36
2.3.4. Mercury Intrusion Porosimetry ................................................................... 37
2.3.5. Compressive Strength of Mortar and Concrete .......................................... 38
viii
2.3.6. Transport Properties .................................................................................... 40
2.3.7. Physical and Chemical Effects of Limestone Filler .................................... 43
2.4. Conclusions ........................................................................................................ 46
2.5. References .......................................................................................................... 47
Chapter 3 - Hydration Kinetics and Compressive Strength of Steam-Cured Cement Pastes
and Mortars Containing Limestone Filler ......................................................................... 51
3.1. Introduction ........................................................................................................ 52
3.2. Experimental Program........................................................................................ 54
3.2.1. Materials and Mix Design ........................................................................... 54
3.2.2. Curing Regime ............................................................................................ 55
3.2.3. Test Methods ............................................................................................... 57
3.3. Results and Discussion ....................................................................................... 58
3.3.1. Influence of Limestone Filler Size and Content ......................................... 58
3.3.2. Influence of Cement Fineness ..................................................................... 74
3.3.3. Influence of Steam Curing Duration ........................................................... 75
3.3.4. Influence of Reacted Limestone Filler ........................................................ 75
3.3.5. Statistical Analysis ...................................................................................... 77
3.4. Conclusions ........................................................................................................ 78
3.5. Acknowledgments .............................................................................................. 79
3.6. References .......................................................................................................... 79
Chapter 4 - Effect of Cement and Limestone Particle Size on the Durability of Steam Cured
Self-Consolidating Concrete ............................................................................................. 83
4.1. Introduction ........................................................................................................ 84
4.2. Experimental Program........................................................................................ 86
4.2.1. Materials ..................................................................................................... 86
4.2.2. Mix Design.................................................................................................. 86
4.2.3. Mixing and Curing ...................................................................................... 88
ix
4.2.4. Test Methods ............................................................................................... 90
4.3. Results and Discussion ....................................................................................... 92
4.3.1. Normal Consistency and Initial Setting Time ............................................. 92
4.3.2. Heat of Hydration ....................................................................................... 93
4.3.3. Thermal Analysis ........................................................................................ 94
4.3.4. Mortar Compressive Strength ..................................................................... 97
4.3.5. Plastic Properties of Concrete ..................................................................... 99
4.3.6. Hardened Properties of Concrete .............................................................. 100
4.3.7. Transport Properties of Concrete .............................................................. 105
4.3.8. Durability Performance of Concrete ......................................................... 106
4.4. Statistical Analysis ........................................................................................... 110
4.5. Conclusions ...................................................................................................... 112
4.6. Acknowledgments ............................................................................................ 113
4.7. References ........................................................................................................ 113
Chapter 5 - Delayed Ettringite Formation in Self-Consolidating Concrete Containing
Limestone Filler .............................................................................................................. 117
5.1. Introduction ...................................................................................................... 118
5.2. Experimental Program...................................................................................... 119
5.2.1. Materials ................................................................................................... 119
5.2.2. Mix Design................................................................................................ 121
5.2.3. Curing Regime .......................................................................................... 122
5.2.4. Testing Methods........................................................................................ 123
5.3. Results and Discussion ..................................................................................... 124
5.3.1. Fresh Properties ........................................................................................ 124
5.3.2. Air Void Analysis of Hardened Concrete ................................................. 125
5.3.3. Compressive Strength ............................................................................... 125
5.3.4. Ultrasonic Pulse Velocity ......................................................................... 130
x
5.3.5. Rapid Chloride Permeability..................................................................... 132
5.3.6. Concrete Expansion .................................................................................. 134
5.3.7. Scanning Electron Microscopy ................................................................. 137
5.3.8. Freeze-Thaw Resistance ........................................................................... 148
5.4. Conclusions ...................................................................................................... 151
5.5. Acknowledgments ............................................................................................ 153
5.6. References ........................................................................................................ 153
Chapter 6 - Key Findings, Contributions and Recommendations .................................. 158
6.1. Key Findings and Contributions ...................................................................... 158
6.2. Recommendations ............................................................................................ 160
Appendix A - Testing Data ............................................................................................. 162
A.1. Particle Size Distribution of Sand and Aggregate .................................................. 162
A.2. Materials Properties ................................................................................................ 163
A.3. Mixing and Batching of Concrete ........................................................................... 164
A.4. Mortar and Concrete Mix Designs .......................................................................... 166
A.5. Chapter 2 Results .................................................................................................... 169
A.6 Chapter 3 Results ..................................................................................................... 170
A.7 Chapter 4 and 5 Results ........................................................................................... 178
A.7.1 Cement Paste and Mortar Results ......................................................................... 178
A.7.2 Fresh Properties of Concrete ................................................................................. 180
A.7.3 Mechanical Properties of Concrete ....................................................................... 181
A.7.4 Transport Properties of Concrete .......................................................................... 195
A.7.5 Durability Performance of Concrete/Mortar ......................................................... 197
A.7.5.1 Concrete Expansion ........................................................................................... 202
A.7.5.1.1 Effect of Limestone Filler ............................................................................... 202
A.7.5.1.2 Effect of Intergrinding Versus Blending of Limestone .................................. 205
xi
A.7.6 Scanning Electron Microscopy ............................................................................. 216
Appendix B Publication Plan ......................................................................................... 229
1
Chapter 1 - Thesis Overview
1.1. Introduction
Concrete is one of the most consumed materials on earth. In Canada, it is estimated that
28.1 million tonnes of concrete are produced annually [1]. This corresponds to
approximately one cubic meter of concrete consumed per capita. The main binding material
in concrete is cement which holds 10 to 15% of concrete volume. In 2004, global cement
production was estimated to be 298 million tonnes and was responsible for 3.8% of the
global CO2 emissions [2]. In 2014, the cement production increased to 4.2 billion tonnes
which was responsible for 9% of global CO2 emissions [3,4]. This is due to the fact that
one tonne of cement produces approximately 900 kg of CO2 [5]. Moreover, the global
demand for cement is increasing and actions have been taken to research other approaches
that could reduce cement consumption. Governments have begun to place a carbon tax on
the production of CO2; such laws were implemented in Canada (in the provinces of Alberta,
British Columbia and Quebec) and in many U.S. states [6]. Currently, the carbon tax varies
from $3.5/tonne of CO2 in Quebec to $30/tonne of CO2 in British Columbia. In 2015,
Ontario started developing its cap and trade program, which will include a carbon tax
system.
The negative environmental impact of cement can be reduced by improving manufacturing
techniques, using alternative fuels or clinker substitution [7]. It has been reported that
improved manufacturing techniques or the use of alternative fuels has less potential for
reduction in CO2 emission compared to cement substitution [7,8]. This is because the main
source of CO2 emission in cement production is the calcination of raw materials which
produces approximately 50 to 55% of the CO2 emission while burning fuels produces 35%
and transportation produces 10% [8]. Cement substitution is reported to be the most
efficient way to achieve a significant reduction of CO2 emission [9]. This substitution can
be done using supplementary cementing materials (SCM) or fillers such as limestone [10,
11]. Fillers are typically finely ground inert materials that are used to reduce the amount of
binding material (i.e., cement). The use of 5% interground limestone as cement
replacement by weight was accepted by the Canadian Standards Association (CSA) A5 in
1983 [12]. In 2009, CSA A23.1 introduced a new type of cement known as Portland
2
limestone cement (PLC), which contains up to 15% of interground limestone by weight
[13]. Limestone can be added either by intergrinding or blending. However, the current
CSA A23.1 allows the use of interground limestone only. In the intergrinding process,
limestone (as coarse particles) is added to the cement clinker and is ground together to
produce the cement. For the blending process, limestone as a powder is blended with the
cement.
Limestone can also be utilized to reduce the cost of concrete [14]. The potential for cost
reduction can be particularly visible in concrete made with high cement contents such as
self-consolidating concrete (SCC), which typically has a higher cost compared to
traditional concrete. The relatively higher cost of SCC is partly due to the necessity for
various chemical admixtures, and more stringent formwork requirements [15,16]. SCC is
also typically made with lower water-to-cement ratios (0.32 to 0.36) compared to
traditional concrete. This increases the portion of cement that remains unhydrated, which
acts as an expensive filler [17].
Utilizing SCC in the construction industry has been proven to have several benefits
including: i) decreasing the labour needs and casting time, ii) eliminating the need for
surface finishing and iii) improving the work environment and safety by reducing noise
exposure and congestion at the casting location [18,19]. Replacing cement with a relatively
less expensive material such as limestone has the potential to be an economical and
environmentally viable option for precast/prestressed SCC if it can achieve the desired
strength gain and durability performance [20,21]. Owing to the importance of early age
strength gain in precast/prestressed applications (demolding or stressing strength: 28 to 35
MPa in the first 16 to 18 hours) it is critical to understand the role of limestone to minimize
any negative impact on the mechanical properties or durability performance. The potential
for negative impact is caused by replacing reactive cementitious materials with less
reactive material (i.e., limestone) and is referred to as the dilution effect [17,22].
The influence of limestone on concrete properties, when cured at an ambient temperature
(i.e., 23°C), has been the focus of many research studies [12,23,24]. However, the results
of the workability, hardened properties and durability performance often vary [12,23]. This
variation in the results could be due in part to the variation in limestone chemical
composition and fineness, and whether the limestone was used as a replacement of cement,
3
sand or cement paste. Inadequate dispersion of limestone particles in the mix may also
cause variations in the results [25]. In addition to the variation in the results, there is limited
data available on the influence of limestone when the concrete is steam cured.
In precast/prestressed applications, high early strength is required to maintain efficient
production. This is usually achieved by applying high temperatures in the range of 60°C to
85°C. Higher temperatures increase the hydration rate and the early age strength gain.
However, concrete subjected to steam curing at elevated temperatures in the range of 60°C
to 75°C (depending on factors including cement chemistry) may be vulnerable to
degradation due to delayed ettringite formation (DEF) [26,27]. Therefore, it is critical to
understand the role of LF and how LF interacts with cementing materials under steam
curing conditions, and how this interaction influences the hardened properties and
durability performance of concrete.
1.2. Research Objectives
The purpose of this thesis is to determine the effect and the mechanisms associated with
replacing 15% of the cement by limestone filler on the mechanical properties and durability
performance of self-consolidating concrete designed and cured for precast/prestressed
applications. To achieve this objective, four questions were explored and answered. The
research questions are:
1. What is the contribution of the physical and chemical effects of LF, and how does
each contribution change with age? (In Chapter 2)
2. What is the effect of LF fineness and content on the hydration kinetics and
hydration products in steam cured mortar and cement paste? (In Chapter 3)
3. How does replacing cement with LF influence the early and later age mechanical
properties, transport properties and durability performance of concrete steam cured
at 55°C? (In Chapter 4)
4. What is the effect of LF on concrete expansion at different steam curing
temperatures (55°C, 70°C and 82°C)? Are there any implications of concrete
expansion due to DEF on the freeze-thaw resistance of concrete made with and
without LF? (In Chapter 5)
4
1.3. Research Outline
The research in this thesis was carried out in four stages and is summarized in Figure 1.1.
Table 1.1 presents the key variables in the experimental study for each chapter. Each
chapter explores one of the four research questions presented in the Research Objectives
(Section 1.2). Chapter 6 presents the key findings and contributions of this thesis.
Figure 1.1: Research Layout
Decoupling the Physical and Chemical Effects of LF
(Chapter 2)
Effect of LF Size and Content
(Chapter 3)
SCC Steam Cured at 55°C with/without LF (Chapter 4)
• Fresh Properties
• Mechanical Properties (Density, fc’, E, UPV)
• Transport Properties (RCPT)
• Durability Performance (Sulfate Resistance, Linear
Shrinkage, Freeze-thaw and Salt Scaling)
Effect of LF on SCC Expansion
Due to DEF
Effect of DEF on Freeze-thaw Resistance of SCC
Containing LF
Effect of Steam Curing Temperatures (i.e., 55°C, 70° and 82°C)
(Chapter 5)
Effect of LF on Transport
Properties of SCCMicrostructure Analysis
• Heat of Hydration
• Thermal Analysis• Compressive Strength
• RCPT & Sorptivity
• Heat of Hydration
• Thermal Analysis
• Compressive Strength
5
Table 1.1: Key Differences between Experimental Work Carried out in Each Chapter
Chapter
Mix Design Parameters Steam
Curing
Temp.
Experimental Variable
System w/c Cement
Type
Silica
Fume Primary Secondary
2
Paste
Mortar
Concrete
0.34 HE 0% 55°C
Effect of LF
(physical vs.
chemical
effect)
---
3 Paste
Mortar 0.37
GU
HE 0% 55°C
LF content
LF size
Cement fineness
Steam curing
duration
4
Paste
Mortar
Concrete
0.34 GU
HE 5% 55°C
LF content
LF size
Cement
fineness
Steam curing
duration
Moist curing
duration
5 Concrete 0.34
GU
HE
GUL
HS
5%
55°C
70°C
82°C
Steam curing
temperature
LF content
LF size
Cement type
Intergrading vs.
blending of
limestone
Moist curing
duration
Chapter 2 is focused on examining the physical and chemical effects of LF on steam cured
cement paste, mortar and concrete. The physical and the chemical effects of LF when used
as a cement replacement were decoupled. This was done using a brucite filler [Mg(OH)2
(BF)] with similar physical characteristics compared to LF. Identifying the relative
contribution of the physical and chemical effects is an important step in understanding how
LF interacts with cementing materials under steam curing conditions. Paste, mortar and
concrete specimens were steam cured at 55°C. The total duration of the steam curing
regime was 16 hours. The heat of hydration, thermal analysis, compressive strength,
mercury intrusion porosimetry and transport properties were evaluated at 16 hours and 28
days.
Chapter 3 is focused on the hydration kinetics and compressive strength of steam-cured
cement pastes and mortars containing LF. The experimental variables in this chapter were
cement fineness, LF content, LF fineness and steam curing duration. Mortar and paste
specimens were steam cured at 55°C. The total duration of the steam curing regime was 12
and 16 hours. Hydration kinetics was studied by examining the heat of hydration and
thermal analysis. The heat of hydration was measured using Isothermal Calorimetry.
Calcium hydroxide (Ca(OH)2) content, calcium carbonate (CaCO3) content and degree of
6
hydration were measured using Thermal Gravimetric Analysis and Differential Thermal
Analysis (TG/DTA). The compressive strength of mortars was evaluated at 12 and 16 hours
and at 3, 7 and 28 days.
In Chapter 4, the findings obtained from Chapters 2 and 3 are utilized to design SCC mixes
that satisfy the early age strength requirements for precast/prestressed concrete applications
in Ontario, Canada (i.e., a minimum of 44 MPa at 16 hours). The influence of cement and
LF particle size on the hardened properties and durability performance of steam cured SCC
was investigated. In addition, the interplay between cement fineness and LF particle size
was evaluated. CSA Type general use (GU) and high early strength (HE) cements were
used with 5% silica fume. LF with two nominal particle sizes of 17µm and 3µm, which
correspond to Blaine finenesses of 475 and 1125 m2/kg, respectively, were used. In
addition to the plastic concrete properties, hardened properties including compressive
strength, elastic modulus, ultrasonic pulse velocity and density were measured at 12 and
16 hours, and at 3, 7 and 28 days. Durability performance including rapid chloride
permeability testing (RCPT), sulfate resistance, linear shrinkage, salt scaling resistance and
freeze-thaw resistance were evaluated.
Chapter 5 is focused on examining the influence of LF on the long-term durability
performance of concrete steam cured at different temperatures. This is important to identify
any negative impact of LF and steam curing temperature on the long-term durability
performance of concrete. The influence of steam curing temperature, cement type, cement
fineness on the expansion of concrete made with and without LF was investigated. Four
types of cement, namely CSA type GU, HE, general use limestone (GUL) and high sulfate
resistance (HS), were used. LF with two nominal particle sizes of 17µm and 3µm were
used to replace 15% of cement. All concrete mixes had 5% silica fume and w/c of 0.34.
The concrete samples were steam cured at a maximum temperature of 55°C, 70°C and
82°C. The total duration of the steam curing regime was 16 hours. The hardened properties
were evaluated using compressive strength and ultrasonic pulse velocity at 16 hours, and
at 3, 7, 28 and 300 days. The transport properties were evaluated using the rapid chloride
permeability test (RCPT) at 28 and 300 days. The durability performance of concrete was
assessed by monitoring concrete expansion and freeze-thaw resistance. Concrete expansion
in water was measured for 300 days followed by freeze-thaw testing for 300 cycles.
7
1.4. Background
1.4.1. Limestone as a Cement Replacement
When replacing cement, limestone influences the behaviour of cement through physical
and chemical effects. The physical effect is caused by (i) modification of particle size
distribution, (ii) dilution and (iii) heterogeneous nucleation. Modification of particle size
distribution and heterogeneous nucleation can improve the properties of concrete whereas
dilution has adverse effects. The chemical effect of limestone is the chemical reaction
between limestone with monosulfate and calcium aluminate hydrates in the hydrated
cement system. The influence of each effect is discussed in the following sections.
1.4.1.1. Physical Effect of Limestone
Modification of Particle Size Distribution
Limestone has a relatively low hardness compared to cement clinker, therefore, when
interground, it produces a wider particle size distribution compared to cement [23,28].
Limestone particles fill the voids between coarser particles (i.e., cement and sand particles),
which can increase the concrete density and decrease the volume of pores in concrete
[22,29]. In fresh concrete, limestone can replace some of the water in the voids. The water
replaced by limestone provides an additional reduction in the internal friction, which causes
an improve in the workability of concrete [24,30]. However, this improvement in the
workability has shown to be insignificant due to the higher water adsorption when
limestone fineness increases [31]. Limestone can also reduce the bleeding of concrete at
replacement levels greater than 5% [32]. At replacement levels of less than 5%, the
bleeding is thought to only be influenced by the surface area of the cement [32].
Dilution
Dilution occurs as a result of replacing reactive material such as cement by an inert or
relatively less reactive material such as limestone [33]. A reduction in the cement content
decreases the volume of hydration products, and adversely affects the compressive
strength, porosity and permeability of concrete. When the content of interground limestone
is greater than 5% in the cement, the effect of dilution masks the other limestone effects
(i.e., modification of particle size distribution, heterogeneous nucleation and chemical
reaction). However, the dilution effect is minimized when limestone content is less than
5% [34]. Although dilution negatively impacts the properties of concrete at all ages, it is
8
mainly observed at later ages (i.e., after 3 days) [35]. This is due to the heterogeneous
nucleation effect of limestone that compensates for the dilution effect at early age (i.e.,
before 3 days) [35].
Heterogeneous Nucleation
Limestone particles act as nucleation sites for the precipitation of the hydration products,
which mainly depends on the fineness of limestone [36,37,38]. The nucleation sites
provided by limestone reduce the energy barrier and allow the hydration products to
precipitate faster from the pore solution. This accelerates the cement hydration process and
early age strength gain [37]. In addition, the surface area of limestone will accommodate
precipitation of some of the hydration products, which reduces the thickness of the
hydration products coating unhydrated cement particles [39]. This allows the inner part of
unhydrated cement particles to hydrate sooner and thus accelerate the hydration process.
1.4.1.2. Chemical Effect of Limestone
Research studies in the past 20 years have proven that limestone is not an inert material but
rather partially reactive [12,24,40]. In the hydrated cement system, limestone chemically
reacts with monosulfate ((CaO)3(Al2O3)·CaSO4·12H2O) and calcium aluminate hydrate
((CaO)3(Al2O3)·6H2O) in the presence of water to form calcium monocarboaluminate
(3CaO·Al2O3·CaCO3·11H2O). The chemical reactions of limestone are presented in
Equations 1.1 and 1.2 [41,42]. The fineness of limestone influences these reactions; the
higher the fineness of limestone, the more limestone is consumed in these reactions [12].
3(CaO)3(Al2O3)·CaSO4·12H2O + 2CaCO3 + 18H2O → 2(CaO)3(Al2O3)·CaCO3·11H2O +
(CaO)3(Al2O3)·3CaSO4·32H2O Eq.1.1
(CaO)3(Al2O3)·6H2O + CaCO3 + 5H2O → (CaO)3(Al2O3)·CaCO3·11H2O Eq.1.2
1.4.2. Energy Saving by Using Limestone
Cement production is considered to be one of the highest energy demanding industries
compared to other mineral-processing industries [43]. Energy consumption is responsible
for approximately 40% of cement production costs [44]. This is because the raw materials
are heated to approximately 1450°C to produce cement clinker [5,45]. The production
process can be classified into two different processes, namely dry and wet processes. The
two processes are similar except that in the wet process the raw materials are ground with
9
water before burning in the kiln [46]. However, in most modern cement manufacturing
plants, the dry process is used. The wet process has greater energy requirements and lower
efficiency compared to the dry process [47]. The energy required for heating raw materials
in a modern dry process cement plant is typically 990 kWh per tonne of cement. This
energy is usually produced by burning coal, oil fuel or natural gas [43]. Once cement
clinker is produced, the clinker is ground using electrical-powered mills to achieve the
required fineness. The grinding process consumes approximately 120 kWh of electricity
per tonne of cement. Therefore, the total amount of fuel or coal required for heating and
grinding is 111 kg of fuel oil or 233 kg of coal to produce one tonne of cement [35].
Replacing clinker with limestone reduces the required energy due to the reduction in the
amount of clinker. However, because limestone is softer than clinker, cement interground
with limestone will have coarser cement particles compared to cement without limestone
[48]. Therefore, it requires more grinding to achieve the same strength of cement without
limestone. When cement contains 5% of interground limestone, the energy required for
extra grinding is estimated to be 2 kWh per tonne of cement. However, this additional
energy is offset by a reduction of 75 kWh per tonne of cement due to the reduction in the
amount of clinker [49].
For a cement plant with a production capacity of 1 million tonnes per year, the total energy
saving is approximately 73 GWh of energy by replacing 5% of cement with limestone.
This energy saving corresponds to approximately 7% of the annual energy usage. The
saving is expected to be higher with an increase in limestone content; however, the
relationship is not linear. Other estimates have shown an annual saving of $420,000USD
per 1% replacement of limestone for cement plant with a production capacity of 1 million
tonnes per year [50].
1.4.3. Economic Evaluation of Using Self-Consolidating Concrete in Precast/Prestressed Applications
The principal disadvantage of SCC is the higher cost compared to traditional concrete due
to the higher cement content and the use of various chemical admixtures [51]. In addition,
SCC requires a more robust formwork system and thus can be costly [51]. However, the
higher costs of materials and formwork when using SCC could be compensated for by the
decrease in construction time as well as a decrease in repair and patching costs due to
10
improved surface finishing. SCC can also reduce labour costs and can compensate for a
lack of skilled workers [52]. Furthermore, SCC eliminates the use of vibrators, which
minimizes the noise and congestion at the casting location. A cost analysis of
precast/prestressed T-girders used for the main girders of the Higashi-Oozu Viaduct in
Japan was conducted [53]. The cost analysis showed that SCC increased the material cost
by approximately 5% compared to traditional concrete. However, this cost increase was
offset by a 33% reduction in labour cost, which yielded a 7% saving in the total cost of the
project compared to traditional concrete. Another cost analysis showed an average
reduction of 44% in man-hours per precast element [54]. In terms of production efficiency,
implementing SCC in precast/prestressed applications can yield up to a 50% reduction in
casting time compared to traditional concrete [55]. Furthermore, SCC can reduce up to
10% of the cost when used for precast elements with a high surface-to-volume ratio (i.e.,
slabs) due to the elimination of screeding [54].
1.4.4. Effect of Steam Curing Temperature
Although steam curing increases the early age strength of concrete, the 28-day compressive
strength could be reduced compared to moist cured concrete [56,57]. A maximum steam
curing temperature of 82°C was suggested to prevent any significant decrease in the 28-
day strength compared to concrete cured at maximum temperatures of 43°C and 63°C [58].
More recent studies suggested using lower steam curing temperatures (50°C to 70°C) to
prevent any long-term strength or durability issues caused by degradation due to delayed
ettringite formation (DEF) [26,27,59].
1.4.4.1. Delayed Ettringite Formation
DEF is a type of internal sulfate attack, and is one of the main concerns in
precast/prestressed applications largely owing to the commonly used elevated curing
temperatures.
Mechanism of Delayed Ettringite Formation
For DEF to occur, three conditions need to exist: exposure to elevated temperature at early
age, sufficient sulfate content in the cement and a supply of moisture [26,60,61]. A
thermodynamic stability study conducted on ettringite showed that ettringite is not stable
at temperatures greater than 60°C because it transforms to monosulfate and gypsum, as
presented in Figure 1.2 [62]. However, in context with cement-based systems and at
11
temperatures greater than 60°C, ettringite can exist if enough sulfate is available in the
system [26]. The ability of calcium silicate hydrate (CSH) to adsorb sulfate ions is
increased with the increase in temperature [63]. This adsorption process is further increased
as the pH increases, which is mainly linked to the alkali content of the cement [26,64].
When the temperature decreases, the sulfate ions are slowly released. Monosulfate in the
presence of sulfate ions and moisture transform to ettringite. A portion of this ettringite
known as DEF forms in the paste, which causes the paste to expand and crack [26].
Ettringite has been reported to exist in cracks in mortar and concrete deteriorated by DEF.
However, the ettringite forming in cracks is not the cause of DEF damage. This formation
of ettringite in the cracks is a recrystallization of ettringite commonly referred to as
secondary ettringite, which occurs after the cracks have been created [65]. In the presence
of cracks, the volume of water ingress into the concrete increases, which promotes the
dissolution process of small ettringite crystals and recrystallization in existing spaces
including air voids and cracks [65].
Factors Influencing Delayed Ettringite Formation
The main factors that influence the risk of DEF are (i) exposure to elevated temperatures
(greater than 70°C) at early age, (ii) high sulfate content (greater than 4% by weight of
cement) and (iii) exposure to a wet environment [26,65,66]. Exposing the concrete at early
age to temperatures greater than 70°C increases the risk of DEF [26]. This is due to the
increase in sulfate ions adsorbed by the CSH, which are later released over time after
concrete is cooled and hardened [26,27]. The expansion of concrete due to DEF is greatly
influenced by the presence of water. Water is an essential part of the reaction to form
ettringite since one molecule of ettringite contains 32 molecules of water. The water also
plays an important role in the leaching of alkali from the concrete [67]. The reduction in
alkalinity due to leaching or alkali silica reaction increases the risk of DEF [67]. It has been
reported that for concrete, a minimum of 92% relative humidity is required for DEF
expansion to occur [68,69].
The alkali content in the cement also plays an important role in the damage due to DEF. In
concrete exposed to elevated temperatures greater than 70°C, the increase in pH of the pore
solution due to the high alkali content in cement increases the amount of sulfate ions
adsorbed to CSH. The increase in alkali content in the cement increases the solubility of
12
ettringite [67]. This increase in the solubility of ettringite is greater with the higher
temperatures.
Cements with higher fineness have been reported to have increased risk to DEF [70,71].
The increased risk to DEF in finer cement could be partly due to the higher gypsum content
compared to coarser cement, which is required to control the rapid hydration of finer
cement.
The use of some pozzolanic materials or SCM such as fly ash, slag and metakaolin at
replacement levels of 15% to 35% of cement can reduce the vulnerability to DEF [59,72].
Silica fume (SF) was reported to be less effective in reducing the risk due to DEF at
replacement levels less than 15% [72]. This was attributed to the lower alumina content in
SF [72]. Entrained air voids can provide some physical protection to the concrete by
providing relief valves for ettringite growth in hardened concrete [73]. However, the
entrained air voids do not prevent DEF. They allow some of the ettringite to form in the air
voids as a secondary ettringite rather than forming as DEF in the confined paste pore
structure [74].
Figure 1.2: Thermodynamic Stability of AFt and AFm Phases in Hydrated Cement
System [62]
13
Effect of Limestone on Delayed Ettringite Formation
There is limited information in the literature on how limestone influences concrete
expansion due to DEF. A study by Silva et al. (2010) showed that an increase in limestone
content increased the expansion of concrete due to DEF [75]. The authors attributed this
increase to the denser microstructure, observed by petrographic analysis of concrete mixes
made with limestone, which reduced the available space that can accommodate the growth
of ettringite. In contrast, a study by Kurdowski and Duszak (2002) has shown that
limestone and fly ash have a similar efficiency in reducing concrete expansion due to DEF
[76]. Al Shamaa et al. (2016) studied the effect of limestone size on mortar expansion due
to DEF [77]. The results showed that the decrease in limestone size decreased the
expansion of mortar. The authors attributed this reduction to the increase in limestone
reactivity and the production of calcium monocarboaluminate, which reduces the transport
properties of the mortar. However, in this study [77], no control mixture without limestone
was used, and therefore, the effect of limestone on mortar expansion could not be
evaluated.
1.4.4.2. Maximum Holding Temperature Limits in North American Codes
Controlling the curing temperature of concrete is critical to reduce the risk of DEF. In North
America, Canadian Standards Association (CSA A23.4) sets the maximum curing
temperature at 60°C. However, for concrete that will be dry in-service, the maximum
curing temperature is 70°C. The Ontario Provincial Standard Specifications OPSS909 and
OPSS999F31 set the maximum steam curing temperature to 60°C for non-prestressed
concrete and 70°C for prestressed concrete. Table 1.2 provides examples of codes and their
recommended maximum curing temperatures pertaining to North America [78]. However,
it should be noted that both Washington and New York DOT have specified a limit of
0.75% and 0.70% on alkali content in cement, respectively [79,80]. This may explain the
relatively higher temperature allowed by Washington and New York DOT.
14
Table 1.2: Maximum Allowable Curing Temperatures
Code Maximum Allowable Steam Curing
Temperature (°C)
Canadian Standards Association (CSA A23.4
2009 reaffirmed 2014)
60°C for wet exposure
70°C for dry exposure
Ontario Provincial Standard Specification
(OPSS 909 and OPSS999F31)
70°C for prestressed concrete
60°C for non-prestressed concrete
Michigan DOT (2004) 70°C
Portland Cement Association (2006) 71°C, however 60 is recommended
AASHTO LRFD Bridge Design
Specifications (2004) 71°C
Washington DOT (2002) 80°C
New York State DOT (2002) 85°C
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23
Chapter 2 - Physical and Chemical Effects of Limestone Filler on Steam Cured Cement Paste, Mortar and Concrete
Abstract
A method to decouple the physical and chemical effects of limestone filler when used as a
cement replacement is proposed. Limestone filler and a chemically inert material (brucite
Mg(OH)2) with similar physical properties to limestone filler were used. Paste, mortar and
concrete specimens were steam cured at 55°C for 16 hours. The heat of hydration, thermal
analysis, x-ray diffraction, compressive strength, mercury intrusion porosimetry and
transport properties were evaluated at 16 hours and at 28 days. The results showed that
limestone filler can adversely affect the properties of concrete through the dilution effect.
However, heterogeneous nucleation compensates for the dilution effect at 16 hours while
the production of monocarboaluminate compensates for the dilution effect at both 16 hours
and 28 days.
Keywords: Limestone filler, compressive strength, heterogeneous nucleation, dilution,
monocarboaluminate.
2.1. Introduction
Global cement production was estimated to be 4.2 billion tonnes in 2014 due to the fact
that concrete is the second most consumed material on earth after water [1,2]. Cement
production has a significant environmental impact as it is responsible for 9% of the
worldwide manmade CO2 emission [2,3]. This is due to the fact that producing one tonne
of cement produces approximately 900 kg of CO2 of which 450 kg is produced from the
decomposition of raw materials and 360 kg from burning fuel [3]. Replacing cement with
supplementary cementing materials or fillers such as limestone filler (LF) has been one
approach to reduce the negative environmental impact of concrete [4]. In addition, LF can
reduce the cost of cement production. This is mainly due to the lower cost and hardness of
LF compared to cement clinker [5].
Limestone has been accepted as a cement replacement in many standards around the world.
For example, the use of interground limestone as a cement replacement has been accepted
in many standards in Europe since 1960, Canadian Standard Association (CSA) in 1983,
24
and ASTM C150 in 2004 [6]. However, all of these standards have set a maximum
interground limestone content which ranges from 5% to 15% [6,7].
When replacing cement, limestone influences the behavior of cement through physical and
chemical effects. The physical effect is caused by (i) modification of particle size
distribution, (ii) dilution and (iii) heterogeneous nucleation. Modification of particle size
distribution and heterogeneous nucleation can improve the properties of concrete whereas
dilution has an adverse effect. The chemical effect of limestone is caused by the chemical
reaction between limestone with monosulfate and calcium aluminate hydrate in the
hydrated cement system.
Physical Effect of Limestone
(i) Modification of the particle size distribution due to the presence of limestone is
primarily attributed to its relatively lower hardness compared to cement, and so when
ground it yields a wider particle size distribution [8]. In addition, limestone particles fill
the voids between coarser particles and thus increase the density and reduce total pores
volume of the cement system [9]. Furthermore, limestone can decrease the water demand
by replacing some of the water in the voids. This water provides additional reduction in the
friction between solid particles and thus improves the workability [10]. However, this
effect could be masked by the higher water adsorption when limestone fineness increases
[11]. When limestone particles are finer than cement, limestone can reduce the bleeding of
concrete through water adsorption at replacement levels greater than 5% [12]. At a
replacement level less than 5%, the bleeding is thought to only be influenced by the surface
area of the cement [12].
(ii) Dilution occurs when a reactive material such as cement is replaced by a nonreactive
or relatively less reactive material such as limestone [13]. Reducing the cement content
decreases the amount of hydration products and cause adverse effects on the compressive
strength at early and later ages, the porosity and the permeability of concrete. The dilution
effect masks any other limestone effects at replacement level greater than 5%. Below 5%,
the dilution effect is insignificant [14]. The dilution effect influences the properties of the
cement system at all ages. However, it is mainly observed after 3 days [15]. This can be
attributed to the heterogeneous nucleation effect of limestone which compensates for the
dilution effect at early age (i.e., before 3 days).
25
(iii) Limestone particles act as nucleation sites for the precipitation of the hydration
products [13]. However, this effect depends mainly on the fineness of limestone. The
increase in limestone fineness increases the nucleation sites for the precipitation of the
hydration products [16]. The nucleation sites provided by limestone particles allow the
hydration products to precipitate faster from the pore solution causing faster early age
strength gain [13]. In addition, the surface area of limestone particles accommodates some
of the hydration products. This reduces the thickness of the hydration products coating
unhydrated cement particles and allows faster hydration of the inner part of the cement
particles [17].
Chemical Effect of Limestone
Research studies have shown that limestone is not a chemically inert material but rather a
partially reactive material [7,10]. Limestone chemically reacts with calcium aluminate
hydrate ((CaO)3(Al2O3)·6H2O) and monosulfate ((CaO)3(Al2O3)·CaSO4·12H2O) to form
calcium monocarboaluminate (3CaO·Al2O3·CaCO3·11H2O), as presented in Equations 2.1
and 2.2 [18,19,20]. The reactions between limestone and monosulfate and calcium
aluminate hydrate take place after the exhaustion of sulfate ions in the system [21]. The
increase in limestone fineness increases the reactivity of limestone [7].
3(CaO)3(Al2O3)·CaSO4·12H2O + 2CaCO3 + 18H2O → 2(CaO)3(Al2O3)·CaCO3·11H2O +
(CaO)3(Al2O3)·3CaSO4·32H2O Eq.2.1
(CaO)3(Al2O3)·6H2O + CaCO3 + 5H2O → (CaO)3(Al2O3)·CaCO3·11H2O Eq. 2.2
The influence of limestone on the concrete properties and performance have been fairly
reported in the literature [7,10,13]. However, most of the reported data are for concrete
cured at ambient temperature (i.e., 23°C) and there is limited data on the influence of
limestone under steam curing conditions [6,7,22]. While the influence of limestone is
caused by a combination of physical and chemical effects, no elaboration on the influence
of each effect has been reported. Therefore, it is essential to identify the influence of each
effect to understand how limestone interacts in the cement system and to optimize the use
of limestone for the precast/prestressed applications.
The aim of this chapter is to decouple the physical and chemical effects of LF on the
hardened and transport properties of concrete. This was achieved by using LF and an inert
26
filler (brucite, Mg(OH)2) with similar particle size distribution and fineness. Brucite (BF)
is an inert material by nature but could chemically react with the amorphous silica in fly
ash under sulfate-rich environment [23,24]. However, this condition at which BF can
chemically react does not apply in this work and therefore, BF was considered an inert
material. BF was used to evaluate and measure the combined physical effects of LF while
LF was used to measure the combined physical and chemical effects. The difference in
performance between LF and BF mixtures is attributed to the chemical reaction of LF.
Three mixtures were considered in this chapter. For each mixture, paste, mortar and
concrete were prepared. The first mixture was made of 100% of CSA type HE cement with
no interground limestone. The second and the third mixtures were made by replacing 15%
of the cement with LF and BF, respectively. The specimens were steam cured at 55°C. The
total duration of the steam curing regime was 16 hours. Following steam curing, the
specimens were moist cured in limewater until testing. The physical and chemical effects
of LF on the heat of hydration, chemical composition, compressive strength, pore size
distribution and transport properties were evaluated. The heat of hydration of cement pastes
was measured at 23°C and 55°C for a duration of 72 hours using isothermal calorimetry.
The chemical composition of cement pastes was measured at 16 hours (following steam
curing) and at 28 days (16 hours of steam curing followed by moist curing until the age of
28 days) using thermal analysis. The cube compressive strength of mortars and the concrete
compressive strength were evaluated at 16 hours and 28 days. The pore size distribution of
mortars was evaluated using mercury intrusion porosimetry (MIP) at 16 hours and 28 days.
The transport properties of cement paste, mortar and concrete were evaluated using rapid
chloride permeability test (RCPT) and sorptivity test at 16 hours and 28 days.
2.2. Experimental Program
2.2.1. Materials
Since all CSA type GU cement produced in Ontario, Canada, contains up to 5% of
interground LF, CSA type HE cement with no interground limestone was used. The cement
was supplied by Lafarge Canada Inc. The chemical and the physical properties of cement
are presented in Table 2.1. LF (97% calcium carbonate) and brucite (99% Mg(OH)2, which
will be referred to as BF) were supplied by Omya Canada Inc. and Aldon Corporation,
respectively. The selection of BF was based on the chemical reactivity and hardness. BF is
27
an inert material and has similar Mohs Hardness (i.e., 3) compared to LF [24,25]. The
hardness of BF and LF should be similar to avoid introducing a new variable in the
compressive strength results [26]. LF with nominal particle size of 3µm was selected
because it had close particle size and Blaine fineness compared to the supplied BF. LF had
a Blaine fineness of 1125 m2/kg, median particle size of 3µm and specific gravity of 2.7.
The supplied BF had a Blaine fineness of 1450 m2/kg, median particle size of 4µm and
specific gravity of 2.4. Since the particle size distribution and the Blaine fineness of the
supplied LF and BF were slightly different, both materials required modification in the
particle size distribution to achieve similar particle size distribution and Blaine fineness.
This modification consisted of sieving LF and BF using 10µm, 7µm, 5µm and 2µm sieves
and using equal proportion retained on each sieve. The sieving was conducted to ensure
similar particle size distribution of LF and BF. In addition, the portion of LF passing 2µm
sieve was ground so that the final LF product has a Blaine fineness of 1450 ± 30 m2/kg
which is similar to BF. The particle size distribution of cement, LF and BF is presented in
Figure 2.1. The fine aggregate was natural sand with a specific gravity of 2.72 and a
fineness modulus of 2.84. The coarse aggregate was crushed limestone with a maximum
size of 13 mm. The sand and coarse aggregates were supplied by Dufferin Aggregates.
Plastol 6400, a high-range water reducer (HRWR), supplied by Euclid Chemical was used.
Table 2.1: Chemical and Physical Properties of Cement
Chemical and Physical Properties HE Cement
SiO2 (%) 19.7
Al2O3 (%) 5.0
Fe2O3 (%) 3.3
CaO (%) 61.8
MgO (%) 2.5
SO3 (%) 4.1
Na2Oeq (%) 0.7
C3S (%) 54.0
C3A (%) 8.0
C4AF (%) 10.0
C2S (%) 14.0
LOI at 1150 °C (%) 0.9
Blaine (m2/kg) 505
28
Figure 2.1: Particle Size Distribution of Cement, LF and BF
2.2.2. Mix Designs
Three mix designs were prepared. For each mix design, cement paste, mortar and concrete
were prepared. The details of the mixtures are presented in Table 2.2 for cement paste and
mortar mixes and Table 2.3 for concrete mixes. LF and BF were used to replace 15% by
weight of the cement. The water-to-cement ratio (w/c) was kept constant in paste, mortar
and concrete at 0.34 to represent the w/c used in SCC. LF and BF were not considered a
cementing material in w/c calculations. No HRWR was used in cement pastes to prevent
any alteration in the results of heat of hydration or thermal analysis. The sand-to-cement
ratio in the mortar mixtures was 2. Concrete had total cement and coarse aggregate contents
of 450 kg/m3 and 900 kg/m3, respectively. Concrete mixing was done in a 30-litre drum
mixer.
0
10
20
30
40
50
60
70
80
90
100
1 10 100
Per
centa
ge
Pas
sing (
%)
Particle Size (µm)
Cement LF and BF
29
Table 2.2: Cement Paste and Mortar Mixture Details
Mix
ID
Cement
(% by
weight)
Cement
Replacement
(% by weight)
Sand/Cement
Ratio for
Mortar
w/c
Ratio
LF BF
C 100 0 0 2
0.34 LF 85 15 0 2
BF 85 0 15 2
Table 2.3: Concrete Mix Designs
Mix
ID
Cement LF BF Coarse
Agg.
Fine
Agg. Water HRWR
(ml/100kg) kg/m3
C 450.0 0 0 900 920 153.0 300
LF 382.5 67.5 0 900 955 130.1 1200
BF 382.5 0 67.5 900 945 130.1 1200
2.2.3. Curing Regime
Paste, mortar and concrete specimens were steam cured at 55°C and 95% relative humidity
(RH) for 16 hours, as presented in Figure 2.2. A 0.45 m3 environmental chamber
manufactured by Cincinnati Sub-Zero was used. The relative humidity in the chamber was
controlled by a steam generator built into the chamber. A maximum curing temperature of
55°C was used in order to prevent any alteration in the microstructure due to delayed
ettringite formation [27]. Following steam curing, the specimens were moist cured in
limewater at 23°C until tested.
30
Figure 2.2: Steam Curing Regime
2.2.4. Test Methods
Cement paste specimens were used for heat of hydration, thermal analysis and transport
properties measurements. Mortar specimens were used for cube compressive strength, MIP
and transport properties testing. Concrete specimens were used to measure the compressive
strength and transport properties.
Heat of Hydration: For each mixture, three cement paste samples were tested for the heat
of hydration at 23°C and 55°C over a period of 72 hours in accordance with ASTM C1702-
09 Method B. A TAM Air isothermal calorimeter manufactured by Thermometric was used
to test the cement pastes at 23°C. At 55°C, I-Cal 8000 isothermal calorimeter manufactured
by Calmetrix was used. Before mixing the cement pastes, all materials were preconditioned
to a temperature within ± 2°C of the isothermal calorimeter testing temperature. This was
done by placing the materials in the environmental chamber set at ± 2°C of the isothermal
calorimeter testing temperature for 2 hours.
Thermal Analysis: Calcium hydroxide (Ca(OH)2), calcium carbonate (CaCO3) and
magnesium hydroxide (Mg(OH)2) contents were measured at 16 hours and 28 days using
Thermal Gravimetric /Differential Thermal Analysis (TG/DTA). For each mix design, two
TG/DTA tests were conducted. The tests were conducted using Netzsch SA Simultaneous
10
15
20
25
30
35
40
45
50
55
60
0 2 4 6 8 10 12 14 16 18
Tem
per
ature
(°C
)
Time (hour)
Curing Regime Internal Temperature of Specimens
95% RH
31
Thermal Analyzer heated to 1100°C at a heating rate of 10°C/min. Ca(OH)2 content was
used to evaluate the hydration products for each mixture. The paste samples were freeze-
dried until a constant mass. In the freeze-drying process, the samples were frozen in liquid
nitrogen to stop the hydration reactions. After that, the samples were placed in a sealed
desiccator under vacuum at -10°C. The samples were freeze-dried until a constant mass
(less than 0.1% change in a 24-hour period) was achieved.
CaCO3 content was used to calculate the amount of LF that was consumed in the chemical
reaction. The initial CaCO3 content (prior to mixing), expressed in percentage by weight
(wt%), was calculated according to Equation 2.3. The final CaCO3 content was calculated
using TG/DTA mass loss at approximately 680 to 800°C, as presented in Equation 2.4 [28].
The amount of reacted LF was calculated using Equation 2.5.
Initial CaCO3 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑜𝑓 𝐿𝐹
𝑇𝑜𝑡𝑎𝑙 𝑀𝑎𝑠𝑠 (𝑐𝑒𝑚𝑒𝑛𝑡+𝐿𝐹+𝑤𝑎𝑡𝑒𝑟)× 100 Eq.2.3
Final CaCO3 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (680 − 800°C ) ×Molar Mass of CaCO3
Molar Mass of CO2 Eq. 2.4
Reacted LF (wt%) = Initial CaCO3 content – Final CaCO3 content Eq.2.5
Similarly, the initial content of BF was calculated using Equations 2.6. Mass loss
corresponding to the decomposition of BF between 350 and 400°C was used to calculate
the final BF content, as presented in Equation 2.7 [28]. Ca(OH)2 content was measured
using TG/DTA mass loss between 450 to 500°C, as presented in Equation 2.8 [28].
Initial BF Content (wt%) = 𝑀𝑎𝑠𝑠 𝑜𝑓 Mg(OH)2
𝑇𝑜𝑡𝑎𝑙 𝑀𝑎𝑠𝑠 (𝑐𝑒𝑚𝑒𝑛𝑡+𝑀𝑔+𝑤𝑎𝑡𝑒𝑟)× 100 Eq.2.6
Final BF Content (wt%) = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (350 − 400°C ) ×Molar Mass of Mg(OH)2
Molar Mass of H2O Eq. 2.7
Measured Ca(OH)2 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (450 − 500°C ) ×Molar Mass of Ca(OH)2
Molar Mass of H2O
Eq. 2.8
X-Ray Diffraction: The x-ray diffraction was used to identify the calcium
monocarboaluminate phase. At 28 days, paste samples were dried in a vacuum oven at
38°C for 24 hours. Prior to x-ray testing, the samples were crushed and sieved to obtain a
powder with particle size of less than 45μm.
32
Mortar Compressive Strength: The cube compressive strength of mortar samples was
measured in accordance with ASTM C109-12. For each mortar mixture, three cubes were
tested at 16 hours and at 28 days.
MIP: The pore size distribution and the total porosity of mortars were measured using MIP.
The Samples were pressurized up to 413 MPa using automated porosimeter manufactured
by Quantachrome Instruments. Before testing, the samples were freeze-dried until a
constant mass (less than 0.1% change in a 24-hour period) was achieved.
Concrete Compressive Strength: The compressive strength of concrete was measured using
200 mm × 100 mm cylinders at 16 hours and 28 days [29]. For each mix design, three
cylinders were tested at each age.
Transport Properties: The transport properties of cement paste, mortar and concrete
specimens were evaluated using RCPT and sorptivity at 16 hours and 28 days. The RCPT
were conducted in accordance with ASTM C 1202 and sorptivity tests were conducted
according to ASTM C 1585. For each test, three concrete samples were tested and the
average value is reported.
2.3. Results and Discussion
2.3.1. Heat of Hydration
The total heat released during the first 40 hours of hydration from each paste cured at 23°C
and 55°C is presented in Figure 2.3. At a curing temperature of 23°C, during the first 12
hours of hydration, mixes made with LF and BF showed higher total heat released
compared to the control mixture made of 100% cement. At approximately 14 hours, the
total heat released from all mixes were similar. After 14 hours, the control mixture made
of 100% cement showed higher total heat released compared to mixes made with LF and
BF. At a curing temperature of 55°C, mix LF showed higher total heat released compared
to mix BF and the control mixture made of 100% cement. Mix BF showed higher total heat
released in the first 18 hours of hydration compared to the control mixture made of 100%
cement. After 18 hours, mixes made with BF and 100% cement had similar total heat
released. The increase in the total heat released of HE cement paste with the addition of
fine particles (i.e., LF and BF) was due to the acceleration in the hydration reactions which
is in alignment with the literature [30,31,32]. The precipitation of the hydration products
33
from the pore solution is assumed to be similar on the surface of LF and BF particles since
both materials have similar physical characteristics.
The physical effect of LF (the difference in the results between the control mixture made
of 100% cement and mix BF) increased the heat of hydration compared to the control
mixture made of 100% cement. This increase is caused by the heterogeneous nucleation
which causes acceleration in the hydration rate. The chemical effect of LF (the difference
in the results between mix LF and mix BF) showed an additional increase in the heat of
hydration. This increase in heat of hydration was caused by the chemical reaction of LF,
which is an exothermic chemical reaction [33]. The combined effect (physical and
chemical) of LF was influenced by curing temperature. This was evident in total heat
released after 40 hours where LF reduced the total heat released when cured at 23°C and
increased the total heat released at 55°C compared to the control mixture made of 100%
cement.
Figure 2.3: Effect of Curing Temperature (23°C and 55°C) on the Total Heat Released of
Cement Pastes
0
50
100
150
200
250
0 5 10 15 20 25 30 35 40
Ener
gy (
J/g)
Time (hours)
C-23°C LF-23°C BF-23°C
C-55°C LF-55°C BF-55°C
23°C
55°C
34
2.3.2. Thermal Analysis
The thermal analysis was conducted to measure the amount of reacted LF and to confirm
that BF is a chemically inert material. In addition, a relative evaluation of the hydration
products was conducted using Ca(OH)2 content. The mass loss from TG analysis and the
DTA results are presented in Figures 2.4 and 2.5, respectively. Figure 2.4 presents the mass
loss with temperature. Figure 2.5(a) presents DTA results for the control mixture made
with 100% cement while Figures 2.5(b) and (c) present DTA results for mixes made with
LF and BF, respectively (please refer to Section A.5 in Appendix A for the raw data and
the statistical analysis). Based on the measured data, Ca(OH)2, CaCO3 and BF contents
were calculated using Equations 2.3 through 2.8. The results in Figures 2.4 and 2.5(b)
showed that the addition of LF increased the Ca(OH)2 content at 16 hours compared to the
control mixture made with 100% cement. The content of Ca(OH)2 increased from 7.4 wt%
in the control mixture made of 100% cement to 8.6 wt% in mix LF. This is expected as the
additional surface area provided by LF acts as nucleation sites for the precipitation of the
hydration products. This accelerates the hydration process resulting in a higher Ca(OH)2
content in mix LF compared to the control mixture made of 100% cement. At 28 days, the
Ca(OH)2 content in mix LF and the control mixture made of 100% cement were
approximately similar (11.9 wt% in the control mixture made of 100% cement and 12.2
wt% in mix LF). CaCO3 content was corrected for LF purity (since the purity of LF was
97% not 100%) and the initial carbonation of the cement. The amount of LF that was
consumed in the reaction in mix LF was 1.3 wt% at 16 hours and 2.4 wt% at 28 days.
Dividing the amount of reacted LF by the initial CaCO3 content yields the percentage of
reacted LF to the total available LF in the system (i.e., 11.0% at 16 hours and 20.9% at 28
days). The amount of reacted LF at 16 hours was approximately 53% of the amount of
reacted LF at 28 days. This indicates that the reaction of LF took place early during the
hydration process and explains the higher heat of hydration in mix LF compared to mix BF
and the control mixture made of 100% cement.
35
Figure 2.4: Effect of Mixture Design on the TG Mass Loss of Cement Pastes at 16 hours
and 28 days
The addition of BF also increased Ca(OH)2 content at 16 hours compared to the control
mixture made of 100% cement, as presented in Figures 2.4 and 2.5(c). The content of
Ca(OH)2 increased from 7.4 wt% in the control mixture made of 100% cement to 8.2 wt%
in mix BF. This is due to the additional surface area provided by BF that acts as nucleation
sites for the precipitation of the hydration products. At 28 days, mix BF and the control
mixture made of 100% cement showed similar Ca(OH)2 content (11.9 wt%). Based on the
mass loss attributed to the decomposition of BF, the final BF content calculated based on
equation 2.7 was 11.6 wt% regardless of testing age (i.e., 16 hours or 28 days). The initial
and final BF content was similar (11.6 wt%). This confirms the chemically inert behaviour
of BF.
70
75
80
85
90
95
100
0 200 400 600 800 1000
Mas
s L
oss
(%
)
Temperature (°C)
C- 16 hours LF-16 hours BF-16 hours
C- 28 days LF-28 days BF-28 days
16 Hrs.
28 Days
36
Figure 2.5: Effect of Mixture Design on DTA Results of Cement Pastes at 16 hours and
28 days (a) 100% Cement, (b) LF and (c) BF
2.3.3. X-Ray Diffraction
The x-ray diffraction was used to confirm the presence of calcium monocarboaluminate in
the hydrated cement paste in mix LF. Figure 2.6 presents the x-ray diffraction results for
the control mix, as presented in Figure 2.6.a and LF mix, as presented in Figure 2.6.b. The
results showed that a peak at approximately 12° 2θ representing calcium
monocarboaluminate was observed in mix LF while no peak was observed in the x-ray
diffraction results of the control mix.
-0.4
-0.2
0.0
0.2
0.4
0.6
0 100 200 300 400 500 600 700 800 900 1000
DT
A/(
µV
/mg)
Temperature (°C)
16 hours
28 days
(a)
Ca(OH)2 decomposition
-0.4
-0.2
0.0
0.2
0.4
0.6
0 100 200 300 400 500 600 700 800 900 1000
DT
A/(
µV
/mg)
Temperature (°C)
16 hours
28 days
(b)
Ca(OH)2 decomposition
CaCO3 decomposition
-0.4
-0.2
0.0
0.2
0.4
0.6
0 100 200 300 400 500 600 700 800 900 1000
DT
A/(
µV
/mg)
Temperature (°C)
16 hours
28 days
(c)
Ca(OH)2 decomposition
Mg(OH)2 decomposition
37
E = Ettringite, MS = Monosulfate, MC = Monocarboaluminate
Figure 2.6: X-Ray Diffraction Analysis of Cement Pastes at 28 days (a) 100% Cement
and (b) LF
2.3.4. Mercury Intrusion Porosimetry
The addition of LF and BF reduced the total porosity at 16 hours compared to the control
mixture made of 100% cement, as presented in Figure 2.7 (please refer to Section A.5 in
Appendix A for the raw data and the statistical analysis). The total porosity of the control
mixture made of 100% cement was 9.3% whereas mix LF and mix BF showed total
porosities of 7.9% and 8.7%, respectively. This is expected as the fine particles of LF or
BF fill the voids between the coarser cement and sand particles and reduce the total
porosity. In addition, the increase in the hydration products including Ca(OH)2 with the
addition of LF and BF reduces the total porosity. Furthermore, the chemical effect of LF
(the difference in the results between mix LF and mix BF) reduced the porosity due to the
production of monocarboaluminate. However, at 28 days, the total porosity of all mixes
was approximately the same (5.8% to 6.2%). Two of the physical effects of LF
(heterogeneous nucleation and modification of particle size distribution) in conjunction
5 7 9 11 13 152θ
E
MS
(a)
5 7 9 11 13 15
2θ
E
MC
(b)
38
with the chemical effect of LF reduced the porosity at 16 hours. However, due to the
dilution effect, the enhancement in the microstructure observed at 16 hours was diminished
at 28 days.
Figure 2.7: Effect of Mixture Design on the Void Size Distribution in Mortars at 16
Hours and 28 Days
Figure 2.7 presents the pore size distribution of mortars at 16 hours and 28 days. At 16
hours, pores larger than 0.01 µm were significantly less in mix LF and mix BF compared
to the control mixture made of 100% cement. Mixes LF and BF showed similar pore
volume distributions between 4 µm and 0.05 µm. However, the volume of pores smaller
than 0.05 µm was less in mix LF compared to mix BF. At 28 days, the pore size distribution
of control mixture made of 100% cement and mix BF were similar. For mix LF, the volume
of pores larger than 0.03µm was less compared to the control mixture made of 100%
cement and mix BF, as presented in Figure 2.7.
2.3.5. Compressive Strength of Mortar and Concrete
The cube compressive strengths of mortars at 16 hours and 28 days are presented in Figure
2.8 (please refer to Section A.5 in Appendix A for the raw data and the statistical analysis).
Each column in Figure 2.8 is the average of three tests. The coefficients of variation were
0.00
0.02
0.04
0.06
0.08
0.10
0.0010.010.1110
Po
re V
olu
me
Pore Size (µm) - Log Scale
C- 16 hours LF- 16 hours BF- 16 hours
C- 28 days LF- 28 days BF- 28 days
39
below 5%. At 16 hours, the addition of LF and BF increased the cube compressive strength
by 7% and 3%, respectively, compared to the control mixture made of 100% cement. At
28 days, the strength of all mixes was approximately similar (90 to 94 MPa).
Figure 2.8: Effect of Effect of LF and BF Filler on the Cube Compressive Strength of
Mortars at 16 Hours and 28 Days Compared to Control Mix
The compressive strengths of concrete mixtures are presented in Figure 2.9 (please refer to
Section A.5 in Appendix A for the raw data and the statistical analysis). Each column in
Figure 2.9 is the average of three tests whereas the coefficients of variation were below
3%. The addition of LF improved the 16-hour compressive strength by 8% compared to
the concrete mixture made with 100% cement. Concrete mixtures made with BF showed
5% increase in the compressive strength compared to the concrete mixture made with 100%
cement. At 28 days, the compressive strength of all concrete mixtures ranged between 82
and 85 MPa.
55
60
65
70
75
80
85
90
95
100
16 hours 28 days
Cub
e C
om
pre
ssiv
e S
tren
gth
(M
Pa)
Age
C LF BF
40
Figure 2.9: Effect of LF and BF Filler on the Concrete Compressive Strength at 16 Hours
and 28 Days Compared to Control Mix
The results of the compressive strength of mortar and concrete specimens are in agreement.
The increase in the 16-hour compressive strength with the addition of BF (i.e., the physical
effect of LF) was caused by two factors. Firstly, the fine particles of BF fill the voids
between the larger particles, which reduces the porosity and increase the strength.
Secondly, the increase in hydration rate with the addition of BF increases the hydration
products and thus reduces the porosity and increase the strength. This agrees with the
results obtained from the heat of hydration, thermal analysis and MIP. The chemical effect
of LF (i.e., the difference between mix LF and mix BF) increased the strength at 16 hours.
Although a distinct effect of LF and BF was observed in heat of hydration, thermal analysis,
MIP and compressive strength results at 16 hours, no effect was observed at 28 days. This
is due to the dilution effect which is in alignment with the literature [13,14,15].
2.3.6. Transport Properties
The transport properties including RCPT and sorptivity test were conducted on paste,
mortar and concrete specimens. The purpose of testing the transport properties of cement
paste, mortar and concrete is to evaluate the influence of LF on the microstructure of the
55
60
65
70
75
80
85
90
16 hours 28 days
Co
ncr
ete
Co
mp
ress
ive
Str
ength
(M
Pa)
Age
C LF BF
41
cement system in the presence of aggregate (i.e., sand particles in mortars and sand and
coarse aggregates particles in concrete).
The RCPT values are presented in Table 2.4. Each value in the table is the average of three
tests. The coefficients of variation were below 4% (please refer to Section A.5 in Appendix
A for the raw data and the statistical analysis). Paste specimens showed the highest RCPT
values followed by mortar and concrete specimens. This is due the fact that the electrical
charge (Coulombs) passes mainly through the saturated capillary pores in the cement paste
[34]. Therefore, the addition of sand in mortar or sand and coarse aggregate in concrete
reduces the volume proportion of the cement paste and thus reduces the RCPT values, as
presented in Table 2.4. The maximum temperature reached during the test ranged from
38°C to 46°C in concrete specimens, 42°C to 56°C in mortar specimens and 57 to 68°C in
paste specimens. This is expected as the increases in the electrical charge passing through
the RCPT specimen increases the temperature of the specimen. The maximum temperature
in pastes specimens was less than the 80°C limit required to prevent any damage to the
RCPT cell. The addition of LF or BF reduced the RCPT values at 16 hours and 28 days
compared to the control mixture made of 100% cement. The reduction in the RCPT values
when LF and BF were used was below 9% at 16 hours regardless of specimen’s type (i.e.,
paste, mortar and concrete). However, at 28 days, LF caused a significant reduction in the
RCPT values (12%, 21% and 28% in paste, mortar and concrete specimens, respectively).
The reduction in the RCPT values when BF was used was 5%, 11% and 14% in paste,
mortar and concrete specimens, respectively.
The initial sorptivity results are presented in Table 2.5. Each value in the table is the
average of three tests. The coefficients of variation were below 5% (please refer to Section
A.5 in Appendix A for the raw data and the statistical analysis). The initial sorptivity results
were higher in the paste specimens followed by mortar and concrete specimens. This is due
to the fact that water is absorbed through the paste portion of the specimen. Since paste
specimens have the highest paste volume followed by mortar and concrete specimens (as
presented in Table 2.5), the sorptivity is expected to be the highest in paste specimens
followed by mortar and concrete specimens. The addition of LF reduces the initial
sorptivity at 16 hours and 28 days compared to the control mixture made with 100%
cement. The reduction in the initial sorptivity was approximately 5% at 16 hours regardless
of specimen type (i.e., paste, mortar and concrete). At 28 days, the reduction in the initial
42
sorptivity was 9% in paste, 12% in mortar and 14% in concrete specimens. The addition of
BF decreased the initial sorptivity by approximately 5% at 28 days while no significant
effect was observed at 16 hours compared to the control mixture made of 100% cement.
The reduction in the transport properties in the presence of LF (i.e., physical effect) at 16
hours was likely caused by the ability of LF to fill the voids between coarser particles,
accelerate the hydration rate, and produce calcium monocarboaluminate that fills the voids
and reduces the permeability. The chemical effect of LF (i.e., the difference between mix
LF and mix BF) was greater at 28 days compared to 16 hours. This is due to the increase
in the amount of reacted LF that produces calcium monocarboaluminate, which fills the
voids and reduces the permeability. By comparing Tables 2.4 and 2.5, it was observed that
the sorptivity test was less sensitive to the change in specimen type (i.e., paste, mortar and
concrete) compared to RCPT.
Table 2.4: RCPT Values of Paste, Mortar and Concrete Specimens
Mix ID Paste Volume
(%)
RCPT (Coulombs)
Paste
16 hours Difference (%) 28 days Difference (%)
C 100 11338 --- 8850 ---
LF 92 10149 -10.5 7783 -12.1
BF 92 10633 -6.2 8388 -5.2
Mortar
16 hours Difference (%) 28 days Difference (%)
C 47.1 4947 --- 3005 ---
LF 45.4 4580 -7.4 2390 -20.5
BF 45.4 4800 -3.0 2665 -11.3
Concrete
16 hours Difference (%) 28 days Difference (%)
C 29.8 2840 --- 1226 ---
LF 25.9 2500 -12.0 882 -28.1
BF 25.9 2760 -2.8 1051 -14.3
43
Table 2.5: Initial Sorptivity Results of Paste, Mortar and Concrete Specimens
Mix ID Paste Volume
(%)
Initial Sorptivity (×10-4 mm/sec0.5)
Paste
16 hours Difference (%) 28 days Difference (%)
C 100 25.6 --- 15.3 ---
LF 92 24.5 -4.3 14.0 -8.6
BF 92 25.1 -2.0 15.0 -2.2
Mortar
16 hours Difference (%) 28 days Difference (%)
C 47.1 16.2 --- 14.8 ---
LF 45.4 15.2 -6.0 13.0 -12.2
BF 45.4 16.0 -1.1 14.0 -5.3
Concrete
16 hours Difference (%) 28 days Difference (%)
C 29.8 11.8 --- 10.1 ---
LF 25.9 11.2 -5.4 8.7 -14.1
BF 25.9 11.8 -0.5 9.5 -6.5
2.3.7. Physical and Chemical Effects of Limestone Filler
As mentioned earlier, LF has physical and chemical effects that influence the properties of
concrete. These effects occur simultaneously and it is difficult to evaluate the contribution
of each effect individually. However, by using an inert material such as BF with similar
physical properties to LF, the physical and chemical effects of LF could be decoupled. The
thermal analysis confirmed the chemically inert behavior of BF. The difference in
performance between mix LF (i.e., combined physical and chemical effects) and mix BF
(i.e., physical effect) defines the influence of the chemical effect of LF (i.e., calcium
monocarboaluminate). In the following discussion, the combined effect of modification of
particle size distribution, dilution and heterogeneous nucleation is referred to as the
physical effect of LF whereas the chemical reaction of LF is referred to as the chemical
effect of LF.
To clearly evaluate the influence of the physical and chemical effects of LF, the difference
in the results between the control mixture made of 100% cement and mix LF and mix BF
is presented in Figure 2.10 for tests conducted at 16 hours and in Figure 2.11 for tests
conducted at 28 days. In these figures, each column presents the percentage difference in
the test results between mix LF and mix BF (i.e., the chemical effect of LF presented in the
44
grey portion of the column) and the percentage difference in tests results between the
control mixture made of 100% cement and mix BF (i.e., the physical effect of LF presented
in the white portion of the column).
Figure 2.10: Physical and Chemical Effect of LF at 16 Hours
At 16 hours, the physical and chemical effects of LF increased the compressive strength of
mortar and concrete, reduced the total porosity and reduced the RCPT and sorptivity of
cement paste, mortar and concrete, as presented in Figure 2.10. However, the contribution
of each effect was not similar in all tests. The chemical effect of LF had greater influence
in reducing the total porosity compared to the physical effect. Although the physical and
the chemical effects of LF had approximately similar influence on the transport properties
of cement pastes, the chemical effect of LF had a greater influence on the transport
properties of mortar and concrete compared to the physical effect of LF.
At 28 days, the physical effect of LF had a negative impact on the compressive strength of
mortar and concrete, as presented in Figure 2.11. To the contrary, the chemical effect of
-6.3
2.85.1
-6.2-3.0 -2.8 -2.0
-1.1 -0.5
-10.0
4.43.2
-4.3
-4.4-9.2
-2.3 -4.9 -4.9
-30
-25
-20
-15
-10
-5
0
5
10
15
Tota
l P
oro
sity
Cu
be
Co
mp.
Str
eng
th
Co
ncr
ete
Com
p.
Str
eng
th
RC
PT
- P
aste
RC
PT
- M
ort
ar
RC
PT
- C
oncr
ete
Sorp
tiv
ity-
Pas
te
Sorp
tiv
ity-
Mo
rtar
Sorp
tiv
ity-
Co
ncr
ete
Dif
fere
nce
Co
mp
ared
to
Mix
C (
%)
Physical Effect Chemical Effect
45
LF increased the compressive strength of mortar and concrete. The physical and chemical
effects of LF showed a similar reduction in RCPT and sorptivity values regardless of
specimen type (i.e., paste, mortar or concrete). The reduction in the RCPT and sorptivity
values due to the addition of LF (i.e., combined physical and chemical effects) was greater
in concrete followed by mortar and paste specimens. This could be attributed to the
presence of interfacial transition zone in mortar and concrete that was densified by the
presence of fine particles of LF [35].
Figure 2.11: Physical and Chemical Effect of LF at 28 Days
It is evident that LF reduces the porosity, increases the compressive strength and reduces
the transport properties of the cement system through physical and chemical effects. The
physical effect of LF had a greater influence on the compressive strength of mortar and
concrete at 16 hours compared to 28 days. This could be due to the dilution effect which is
more pronounced at 28. In addition, a portion of the dilution effect was compensated for
by the acceleration in the hydration reactions at early age (i.e., at 16 hours). The
improvement in the transport properties due to the chemical effect of LF at 28 days was
-2.2 -4.1 -5.2
-11.3 -14.3
-2.2-5.3 -6.5
4.8 2.9
-6.8
-9.2
-13.8
-6.4
-6.9-7.6
-30
-25
-20
-15
-10
-5
0
5
10
15
20
Cu
be
Co
mp.
Str
eng
th
Co
ncr
ete
Com
p.
Str
eng
th
RC
PT
- P
aste
RC
PT
- M
ort
ar
RC
PT
- C
oncr
ete
Sorp
tiv
ity-
Pas
te
Sorp
tiv
ity-
Mo
rtar
Sorp
tiv
ity-
Co
ncr
ete
Dif
fere
nce
Co
mp
ared
to
Mix
C (
%)
Physical Effect Chemical Effect
46
greater than 16 hours. This is due to the increase in the calcium monocarboaluminate
content at 28 days. Calcium monocarboaluminate fills the voids and enhances the
microstructure. This enhancement was in pores less than 0.1µm and clearly observed at 16
hours, as presented in Figure 2.12. Figure 2.12 is a representation of the cumulative pore
size distribution for mixes C, LF and BF at 16 hours adapted from Figure 2.7. The interface
between the hashed pattern and the vertical lines patters in Figure 2.12 represents mix BF
from Figure 2.7. The lower boundary in Figure 2.12 represents mix LF in Figure 2.7.
Figure 2.12: Physical and Chemical Effect of LF on Pore Size Distribution at 16 Hours
The chemical reaction of LF is increased with the increase in LF fineness. Similarly,
increasing LF fineness increases the heterogeneous nucleation (i.e., accelerate the
hydration reaction) and the modification in the particle size distribution of cement system.
Therefore, it would be expected that using finer LF (i.e., finer than 3µm) will yield even
greater positive effect on the mechanical and transport properties of paste, mortar and
concrete compared to what was observed in results of this study.
2.4. Conclusions
Based on the results of this chapter, the following conclusions can be drawn:
(i) The physical effect of limestone filler increases the compressive strength of mortar
and concrete at 16 hours. This increase is due to the acceleration in the hydration
0.00
0.02
0.04
0.06
0.08
0.10
0.0010.010.1110
Po
re V
olu
me
Pore Size (µm) Log Scale
Chemical Effect of LF
Physical Effect of LF
Mix C
47
rate and the reduction in the porosity. However, the increase in the compressive
strength of mortar and concrete was diminished at 28 days due to the dilution effect.
(ii) The chemical and physical effects of limestone filler have similar contributions in
reducing the transport properties of cement paste, mortar and concrete.
(iii) The reactivity of limestone filler and the production of calcium
monocarboaluminate had an important role in enhancing the compressive strength
and microstructure of mortar and concrete specimens at 16 hours and at 28 days.
(iv) The dilution effect adversely affected the mechanical properties of concrete at 28
days. However, the modification of particle size distribution caused by limestone
filler and the production of calcium monocarboaluminate compensated for the
dilution effect.
2.5. References
[1]. U.S. Department of Interior and U.S. Geological Survey (2015). Mineral Commodity
Summaries.
[2]. PBL Netherlands Environmental Assessment Agency, Trends in global CO2
Emissions: 2015 Report, PBL 1803, pp. 1–10.
[3]. Benhelal, E., Zahedi, G., Shamsaei, E., and Bahadori, A. (2013). Global Strategies
and Potentials to Curb CO2 Emissions in Cement Industry. Journal of Cleaner
Production, Vol. 51, pp. 142–161.
[4]. Celik, K., Meral, C., Petek, A., Gursel, A., Mehta, P., Horvath, A., and Monteiro, P.
(2015). Mechanical Properties, Durability, and Life-cycle Assessment of Self-
Consolidating Concrete Mixtures Made with Blended Portland Cements Containing
Fly Ash and Limestone Powder. Cement and Concrete Composites, Vol. 56, pp. 59–
72.
[5]. Bentz, D., Irassar, E., Bucher, B., and Weiss, W. (2009). Limestone Fillers Conserve
Cement: Part 1: An Analysis Based on Power’s Model. Concrete International, pp.
41–46.
[6]. Tennis, P.D., Thomas, M.D.A., and Weiss, W.J. (2011). State-of-the-art Report on
Use of Limestone in Cements at Levels of up to 15 %, PCA R&D SN3148, Portland
Cement Association.
48
[7]. Hooton, R.D., Nokken, M., and Thomas, M.D.A. (2007). Portland-limestone
Cement: State-of-the-art Report and Gap Analysis for CSA A 3000. SN3053, Cement
Association of Canada, pp. 1–59.
[8]. Gunnelius, K.R., Lundin, T.C., Rosenholm, J.B., and Peltonen, J. (2014). Rheological
Characterization of Cement Pastes with Functional Filler Particles. Cement and
Concrete Research, Vol. 65, pp. 1–7.
[9]. Chen, J., Kwan, A., and Jiang, Y. (2014). Adding Limestone Fines as Cement Paste
Replacement to Reduce Water Permeability and Sorptivity of Concrete. Construction
and Building Materials, Vol. 56, pp. 87–93.
[10]. Hawkins, P., Tennis, P., and Detwiler, R. (2003). The Use of Limestone in Portland
Cement: A State-of-the-art Review. Portland Cement Association, Skokie, IL, USA.
[11]. Schmidt, M. (1992). Cement with Interground Additives - Capabilities and
Environmental Relief: Part 1. Zement-Kalk-Gips, Vol. 45, No. 4, pp. 87–92.
[12]. Mohammadi, I., and South, W. (2015). Decision-making on Increasing Limestone
Content of General Purpose Cement. Journal of Advanced Concrete Technology,
Vol. 13, pp. 528–537.
[13]. Irassar, E.F. (2009). Sulfate Attack on Cementitious Materials Containing Limestone
Filler - A Review. Cement and Concrete Research, Vol. 39, No. 3, pp. 241–254.
[14]. Tsivilis, S., Tsantilas, J., Kakali, G., Chaniotakis, E., and Sakellariou, A. (2003). The
Permeability of Portland Limestone Cement Concrete. Cement and Concrete
Research, Vol. 33, No. 9, pp. 1465–1471.
[15]. Kenai, S., Soboyejo, W., and Soboyejo, A. (2004). Some Engineering Properties of
Limestone Concrete. Materials and Manufacturing Processes, Vol. 19, No. 5, pp.
949–961.
[16]. Knop, Y., and Peled, A. (2016). Setting Behaviour of Blended Cement with
Limestone: Influence of Particle Size and Content. Materials and Structures, Vol. 49,
pp. 439–452.
[17]. Lin, F., and Meyer, C. (2009). Hydration Kinetics Modeling of Portland Cement
Considering the Effects of Curing Temperature and Applied Pressure. Cement and
Concrete Research, Vol. 39, No. 4, pp. 255–265.
[18]. Kakali, G., Tsivilis, S., Aggeli, E., and Bati, M. (2000). Hydration Products of C3A,
C3S and Portland Cement in the Presence of CaCO3. Cement and Concrete Research,
Vol. 30, No. 7, pp. 1073–1077.
49
[19]. Bentz, D. (2006). Modeling the Influence of Limestone Filler on Cement Hydration
Using CEMHYD3D. Cement and Concrete Composites, Vol. 28, No. 2, pp. 124–129.
[20]. Kuzel, H., and Baier, H. (1996). Hydration of Calcium Aluminate Cements in the
Presence of Calcium Carbonate. European Journal of Mineralogy, Vol. 8, pp. 129–
141.
[21]. Wang, J. (2010). Hydration Mechanism of Cements Based on Low-CO2 Clinkers
Containing Belite, Ye’elimite and Calcium Alumino-Ferrite. Journal of Materials
Chemistry, Universit´e des Sciences et Technologie de Lille - Lille I.
[22]. Ramezanianpour, A.M., and Hooton, R.D. (2013). Sulfate Resistance of Portland-
limestone Cements in Combination with Supplementary Cementitious Materials.
Materials and Structures, Vol. 46, No. 7, pp. 1061–1073.
[23]. Zhang, T., Vandeperre, L., and Cheeseman, C. (2014). Formation of Magnesium
Silicate Hydrate (M-S-H) Cement Pastes using Sodium Hexametaphosphate. Cement
and Concrete Research, Vol. 65, pp. 8–14.
[24]. Moore, J., Stanitski, C., and Jurs, P. (2009). Principles of Chemistry: The Molecular
Science. 1st Edition, Brooks Cole, USA, pp. 143–148.
[25]. Santhanam, M. (2013). Performance of Cement-based Materials in Aggressive
Aqueous Environments. RILEM State-of-the-Art Reports, Vol. 10, pp. 75–90.
[26]. Zhange, P., Li, S., and Zhange, Z. (2011). General Relationship between Strength
and Hardness. Materials Science and Engineering: A, Vol. 529, pp. 62–73.
[27]. Brunetaud, X., Linder, R., Divet, L., Duragrin, D., and Damidot, D. (2007). Effect of
Curing Conditions and Concrete Mix Design on the Expansion Generated by Delayed
Ettringite Formation. Materials and Structures, Vol. 40, No. 6, pp. 567–578.
[28]. Maria, F. (2011). Handbook of Thermogravimetric System of Minerals and its Use
in Geological Practice. Geological Institute of Hungary, Budapest, Hungary, pp. 13–
55.
[29]. CSA A23.1/A23.2 (2014). Concrete Materials and Methods of Concrete
Construction/Test Methods and Standard Practices for Concrete, Canadian Standards
Association, Toronto, Canada.
[30]. Kumar, A., Oey, T., Falla, G.P., Henkensiefken, R., Neithalath, N., and Sant, G.
(2013). A Comparison of Intergrinding and Blending Limestone on Reaction and
Strength Evolution in Cementitious Materials. Construction and Building Materials,
Vol. 43, pp. 428–435.
50
[31]. Ye, G., Liu, X., De Schutter, G., Poppe, M., and Taerwe, L. (2007). Influence of
Limestone Powder Used as Filler in SCC on Hydration and Microstructure of Cement
Pastes. Cement and Concrete Composites, Vol. 29, No. 2, pp. 94–102.
[32]. Pera, J., Husson, S., and Guilhot, B. (1999). Influence of Finely Ground Limestone
on Cement Hydration. Cement and Concrete Composites, Vol. 21, No. 2, pp. 99–105.
[33]. Chowaniec, O. (2012). Limestone Addition in Cement, Doctoral Thesis, École
Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
[34]. Yang, C.C., and Chiang, C.T. (2005). On the Relationship Between Pore Structure
and Charge Passed from RCPT in Mineral-free Cement-based Materials, Materials
Chemistry and Physics, Vol. 93, No. 1, pp. 202–207.
[35]. Tikkanen, J., Cwirzen, A., and Penttala, V. (2011). Mineral Powder Concrete –
Effects of Powder Content on Concrete Properties, Magazine of Concrete Research,
Vol. 63, No.12, pp. 893–903.
51
Chapter 3 - Hydration Kinetics and Compressive Strength of Steam-Cured Cement Pastes and Mortars Containing
Limestone Filler
Abstract
This chapter aims to evaluate the influence of limestone filler content and fineness on the
hydration kinetics and the compressive strength of steam cured cement mortars and pastes.
Experimental variables were cement fineness, limestone filler content, limestone filler
fineness and steam curing duration. Mortar and paste specimens were steam cured at 55°C
for 12 and 16 hours. The hydration kinetics were evaluated using the heat of hydration and
thermal analysis. The heat of hydration was measured using Isothermal Calorimetry. The
calcium hydroxide (Ca(OH)2) content, calcium carbonate (CaCO3) content and degree of
hydration were measured using thermal gravimetric analysis and differential thermal
analysis. The compressive strength of mortars was evaluated at 12 and 16 hours, and at 3,
7 and 28 days. The results showed an increase in the heat of hydration, Ca(OH)2 content
and early age strength (i.e., at 12 and 16 hours) with the addition of limestone filler. The
results also revealed that the influence of limestone filler on hydration kinetics and strength
was influenced by the finenesses of the limestone filler and the cement. In general, mix
designs containing limestone filler showed improved early age hydration and strength in
mix designs made with higher cement fineness. Increasing limestone filler fineness or
cement fineness reduced the negative impact on the mechanical properties of mortars due
to cement dilution.
Keywords: Limestone filler, Cement fineness, Thermal analysis, Heat of hydration,
Compressive strength
52
3.1. Introduction
Limestone filler (LF) is a fine powder produced from grinding calcitic limestone rocks
obtained from quarries. LF can be utilized as a replacement of cement clinker to reduce
energy consumption and reduce CO2 emission associated with the cement production [1,2].
The effects of LF on the hydration kinetics and compressive strength when concrete is
cured at ambient temperature have been the focus of many research efforts [3,4,5]. The
outcomes indicate that LF influences the cement system through physical and chemical
effects. The physical effects are modification of particle size distribution, heterogeneous
nucleation and dilution [6,7]. The chemical effect is the reaction of LF with monosulfate
and calcium aluminate to form calcium monocarboaluminate.
LF particles fill the voids between coarser cement particles and thus increase the density
and reduce the total pore volume of the cement system [8]. The surface of LF particles acts
as nucleation sites for the precipitation of the hydration products [9]. The nucleation sites
provided by LF reduce the energy barrier and allow the hydration products to precipitate
faster from the pore solution; this increases the rate of hydration reactions and early age
strength gain, which is described as the acceleration effect [10,11,12].
Unlike modification of particle size distribution or heterogeneous nucleation, dilution can
have adverse effects on the strength and durability of concrete. Dilution occurs as a result
of replacing reactive material such as cement by a nonreactive or relatively less reactive
material such as LF [9]. The adverse effect of dilution is mainly due to the reduction in the
hydration products. When LF is used to replace more than 5% of the cement, the dilution
effect masks the other effects (i.e., modification of particle size distribution, heterogeneous
nucleation and chemical reaction). Dilution decreases the compressive strength of concrete
at all ages. However, it is mainly observed at later age (i.e., after 3 days) [13]. This is due
to the heterogeneous nucleation effect of LF that compensates for the dilution effect at
early age (i.e., before 3 days).
There is a general agreement in the literature regarding the reactivity of limestone (CaCO3)
with the monosulfate ((CaO)3(Al2O3)·CaSO4·12H2O) or calcium aluminate hydrate
((CaO)3(Al2O3)·6H2O) to form calcium monocarboaluminate (3CaO·
Al2O3·CaCO3·11H2O), as presented in Equations 3.1 and 3.2 [14,15,16]. However, there
53
is disagreement on the amount of the total available LF in the system that can be consumed
in these reactions [17].
3(CaO)3(Al2O3)·CaSO4·12H2O + 2CaCO3 + 18H2O → 2(CaO)3(Al2O3)·CaCO3·11H2O +
(CaO)3(Al2O3)·3CaSO4·32H2O Eq. 3.1
(CaO)3(Al2O3)·6H2O + CaCO3 + 5H2O → (CaO)3(Al2O3)·CaCO3·11H2O Eq. 3.2
These effects of LF on the hydration rate and the early age strength gain are agreed upon
in the literature for curing at ambient temperature (i.e., 23°C) [18,19,20,21]. This includes
blended or interground limestone at replacement levels up to 5% in CSA type GU cement
and at replacement levels up to 15% in Portland limestone cement (PLC). However, there
is limited data in the literature on how limestone influences the hydration rate and early
age strength gain when concrete is steam cured [18,19]. The hydration reactions under
steam curing conditions are accelerated due to the increase in the temperature. However,
during the steam curing, the chemical reaction of LF is reduced due to that fact that the
solubility of LF decreases with the increase in the temperature [22]. Therefore, the
influence of LF under steam curing conditions is expected to be different compared to
moist curing at ambient temperature.
The study of the interplay between cement type, LF content and LF fineness of steam cured
cement-based material is warranted. The impact of lower solubility of LF and rapid
hydration rate on the behavior of LF under steam curing conditions is important to
understand. This chapter aims to evaluate the influence of LF content and fineness on steam
cured cement paste and mortar. This was achieved by evaluating the effects of LF content
and fineness on the hydration kinetics and the compressive strength of steam cured cement
mortars and pastes. In addition, the reactivity of LF under steam curing conditions was
assessed. Two types of cement were selected, namely CSA general use (Type GU) cement
and high early strength (Type HE) cement to represent the common cements used in the
precast/prestressed concrete applications. Three LFs with different sizes (17µm, 12µm and
3µm) were selected to cover a wide range of particle size distribution. The percentage of
blended LF was 0, 5, 10 and 15% to evaluate the influence of LF at different cement
replacement levels. The maximum steam curing temperature was set at 55°C to prevent
any alteration in the microstructure of cement mortars and pastes due to delayed ettringite
formation [23]. The heat of hydration, phase composition using Thermal gravimetric
54
analysis and differential thermal analysis (TG/DTA) and compressive strength were
investigated. A multiple linear regression analysis was conducted to identify the primary
variables that control the hydration kinetics and the compressive strength evolution from
12 hours to 28 days.
3.2. Experimental Program
3.2.1. Materials and Mix Design
Two types of cement were used, CSA Type general use (GU) and CSA Type high early
strength (HE) cements, both supplied by Holcim Canada. The GU cement had a Blaine
fineness of 392 m2/kg and the HE cement had a Blaine fineness of 514 m2/kg. The GU
cement had 2.5% interground limestone and the HE cement had 3.5% interground
limestone. Three LFs with different nominal particle sizes (17µm, 12µm and 3µm which
correspond to Blaine fineness of 475, 380 and 1125 m2/kg, respectively) were supplied by
Omya, Canada. The chemical and physical properties of cements, and the LF are presented
in Tables 3.1 and 3.2, respectively. The fine aggregate was natural sand with a specific
gravity of 2.72 and a fineness modulus of 2.84. The fine aggregate was supplied by
Dufferin Aggregates.
Table 3.1: Chemical and Physical Properties of Cements
Chemical and Physical Properties Cement Type
GU HE
SiO2 (%) 19.25 19.10
Al2O3 (%) 5.33 5.18
Fe2O3 (%) 2.41 2.35
CaO (%) 62.78 61.60
MgO (%) 2.36 2.35
SO3 (%) 4.01 4.26
Na2Oeq (%) 0.99 1.01
C3S (%) 58.55 55.15
C3A (%) 10.04 9.75
C4AF (%) 7.34 7.14
C2S (%) 11.03 13.18
LOI at 1150 °C (%) 2.27 2.10
Blaine (m2/kg) 392 514
Limestone Content (CaCO3) 2.50 3.50
55
Table 3.2: Chemical and Physical Properties of LF
Chemical and Physical Properties LF Size
17µm 12µm 3µm
LOI at 1050°C (%) 42.8 42.3 42.4
CaCO3 (%) 95.0 96.0 96.0
MgCO3 (%) 2.0 2.0 2.0
% Retained on 44μm mesh 15.000 0.500 0.003
Moisture Loss at 110°C (%) 0.03 0.05 0.08
Blaine (m2/kg) 475 380 1125
Specific Gravity 2.7 2.7 2.7
Twenty mix designs were examined in this chapter. The mix proportions are presented in
Table 3.3. For each mix design, mortars and pastes were prepared. The mortar was used
for the cube compressive strength evaluation and the corresponding paste was used to
measure the heat of hydration, calcium hydroxide (Ca(OH)2) content, calcium carbonate
(CaCO3) content and the degree of hydration. The water-to-cement ratio and sand-to-
cement ratio were kept constant at 0.37 and 2, respectively. Cement, sand and LF (when
used) were blended initially for 2 minutes in a 10-litre mortar mixer. After the addition of
water, the materials were mixed for 4 minutes. Similar mixing procedures were followed
for the corresponding paste mixes. For each mix design, 15 mortar cubes (50 mm × 50 mm
× 50 mm) were prepared for the compressive strength testing and paste was prepared for
the Isothermal Calorimetry and TG/DTA testing.
3.2.2. Curing Regime
Steam curing was conducted in a 0.45 m3 environmental chamber manufactured by
Cincinnati Sub-Zero. After mixing, the specimens were cured at 23°C and 98% relative
humidity (RH) for 2 hours (preset period) to ensure that the steam curing was applied after
the initial setting [24]. The maximum holding temperature of steam curing was 55°C with
a RH of 98% which was controlled by a steam generator built into the chamber. The curing
regime is presented in Figure 3.1. After the preset period, the specimens were steam cured
in the following sequence:
i. heating to 55°C in 2 hours (16°C /hour) while maintaining 98%RH
ii. holding the temperature at 55°C while maintaining 98%RH for 10 hours for the
16-hour curing regime or for 6 hours for the 12-hour curing regime
56
iii. cooling to 23°C in 2 hours (16°C /hour) while maintaining 98%RH (in the
chamber)
The temperature of the chamber was controlled to maintain the required internal
temperature of the samples, using Type T thermocouples embedded in the samples at the
centroid. After 12 or 16 hours, all specimens were moist cured in limewater at 23°C until
tested (i.e., 3, 7 and 28 days). Thermal analysis was conducted after 16 hours of steam
curing and after 28 days (16 hours of steam curing followed by moist curing in limewater
until 28 days). The selection of 16 hours for the thermal analysis was to reflect the common
curing regimes used in the precast/prestressed applications in Ontario, Canada.
Table 3.3: Mortar and Paste Mix Details
# Mix ID Cement (%) Blended LF
W/C ratio Content (%) Size (µm)
1 GU 100 GU 0 ---
0.37
2 GU-5-17µm 95 GU 5
17 3 GU-10-17µm 90 GU 10
4 GU-15-17µm 85 GU 15
5 GU -5-12µm 95 GU 5
12 6 GU-10-12µm 90 GU 10
7 GU-15-12µm 85 GU 15
8 GU-5-3µm 95 GU 5
3 9 GU-10-3µm 90 GU 10
10 GU-15-3µm 85 GU 15
11 HE 100 HE 0 ---
12 HE-5-17µm 95 HE 5
17 13 HE-10-17µm 90 HE 10
14 HE-15-17µm 85 HE 15
15 HE-5-12µm 95 HE 5
12 16 HE-10-12µm 90 HE 10
17 HE-15-12µm 85 HE 15
18 HE-5-3µm 95 HE 5
3 19 HE-10-3µm 90 HE 10
20 HE-15-3µm 85 HE 15
57
Figure 3.1: Steam Curing Regimes
3.2.3. Test Methods
Initial Setting Time: The normal consistency and the initial setting time were measured
according to ASTM C187-11 and ASTM C191-08, respectively.
Heat of Hydration: For each mix design, three cement paste samples were tested for the
heat of hydration over a period of 72 hours. The test was conducted at 23°C in accordance
with ASTM C1702-09 Method B. A TAM Air isothermal calorimeter manufactured by
Thermometric was used.
Thermal Analysis: The TG/DTA analysis was conducted to measure the Ca(OH)2, CaCO3
and non-evaporable water contents. For each mix design, there TG/DTA tests were
conducted. Netzsch SA Simultaneous Thermal Analyzer heated to 1145°C at a heating rate
of 10°C/min was used. The degree of hydration was calculated by dividing the mass loss
between 23°C and 550°C by the maximum theoretical non-evaporable water (i.e., 0.23), as
presented in Equation 3.3 [25]. The selection of this temperature range (i.e., 23°C to 550°C)
to calculate the degree of hydration was due to the fact that most of the non-evaporable
water content is lost below 550°C [25]. The percentage of Ca(OH)2 and degree of hydration
was used as a measure to evaluate the hydration products to provide a relative comparison
between mix designs. The reactivity of LF was evaluated by calculating the difference
between the initial and the final CaCO3 content. The initial content of CaCO3 (prior to
mixing) was calculated according to Equation 3.4. The mass loss at approximately 680 to
10
15
20
25
30
35
40
45
50
55
60
0 2 4 6 8 10 12 14 16 18
Tem
per
atu
re (
°C)
Time (hour)
Curing Regime Actual Temperature
12-hour steam curing regime
16-hour steam curing regime
58
800°C was used to measure the final CaCO3 content as a percentage by weight (wt%) using
stoichiometry, as presented in Equation 3.5 [26]. In Equation 5.5, the blended LF content
was corrected for LF purity. The mass loss at approximately 450 to 500°C was used to
measure the Ca(OH)2 content, as presented in Equation 3.6.
Degree of Hydration = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (23−550°C )
0.23 Eq.3.3
Initial CaCO3 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑜𝑓 𝐿𝐹
𝑇𝑜𝑡𝑎𝑙 𝑀𝑎𝑠𝑠 (𝑐𝑒𝑚𝑒𝑛𝑡+𝐿𝐹+𝑤𝑎𝑡𝑒𝑟)× 100 Eq.3.4
Final CaCO3 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (680 − 800°C ) ×Molar Mass of CaCO3
Molar Mass of CO2 Eq.3.5
Measured Ca(OH)2 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (450 − 500°C ) ×Molar Mass of Ca(OH)2
Molar Mass of H2O
Eq.3.6
The difference between the initial and the final CaCO3 content was assumed to be the
portion of LF that was consumed in the chemical reaction with monosulfate and aluminate
phases in the hydrated cement system to form calcium monocarboaluminate. To accurately
measure the non-evaporable water, the specimens were freeze-dried. The freeze-drying
process consisted of two steps. The first step was freezing the samples using liquid nitrogen
to stop the hydration. The second step was placing the samples in sealed desiccator under
vacuum at -10°C. The samples were freeze-dried until a constant mass (less than 0.1%
change in 24-hour period) was achieved
Compressive Strength: The cube compressive strength of mortar samples was measured in
accordance with ASTM C109-12. For each mortar mix design, three cubes were tested at
12 hours, 16 hours and at 3, 7 and 28 days.
3.3. Results and Discussion
3.3.1. Influence of Limestone Filler Size and Content
3.3.1.1. Initial Setting Time
The normal consistency and the initial setting time were measured for mixtures containing
0% and 15% LF, and are presented in Table 3.4. The addition of LF decreases the initial
setting time for both GU and HE cement pastes. Similar percentage reduction in the initial
setting time was observed in pastes made of GU and HE cement when LF of 17µm or 12µm
59
was used, as presented in Table 3.4. Paste made of GU cement and 3µm LF showed a
relatively higher reduction (14.3%) in the initial setting time compared to paste made with
HE cement and 3µm LF (10.6%). In general, the reduction in LF size from 17µm to 12µm
did not cause any significant change in the initial setting time for pastes made with GU or
HE cement. The increase in the hydration rate and the reduction in the initial setting time
in the presence of LF can be attributed to the increase in nucleation surface area particularly
with 3µm LF size [10,27].
Table 3.4: Normal Consistency and Initial Setting Time
MIX ID Normal
Consistency Initial Setting (mins.)
Reduction in Initial
Setting time (%)*
GU 0.270 98 ---
GU-15-17µm 0.295 94 4.0
GU-15-12µm 0.295 92 6.1
GU-15-3µm 0.300 84 14.3
HE 0.310 94 ---
HE-15-17µm 0.330 90 4.3
HE-15-12µm 0.330 89 5.3
HE-15-3µm 0.335 80 10.6
*Compared to control (GU or HE) mixtures
3.3.1.2. Heat of Hydration
The effect of LF content and size on the heat of hydration of GU and HE mixtures is
presented in Figure 3.2. Figure 3.2a presents the effect of 17µm LF content on the heat of
hydration of GU and HE cement mixtures. Figures 3.2b and 3.2c present the effect of 12µm
and 3µm LF content, respectively. The heat of hydration curves presented in Figure 3.2 are
used to calculate the total energy released presented in Figure 3.3. The presence of LF
increased the heat of hydration regardless of LF content or size compared to pastes made
without LF. The effect of LF was more pronounced in HE mixtures compared to
counterpart GU cement mixtures. It was also observed that the increase in LF content from
5% to 10% to 15% and decrease in LF size from 17µm to 12µm to 3µm increased the heat
of hydration. To further explain these trends, the values of the hydration peak and the total
energy released for the first 20 hours of hydration were compared for each mixture and are
shown in Figures 3.4 and 3.5. The first 20 hours of hydration was selected as a base for
comparison as most of the hydration heat is released during this period.
60
Figure 3.2: Effect of LF on the Heat of Hydration for Pastes with a) 17µm LF, b) 12µm
LF and c) 3 µm LF
0
1
2
3
4
5
6
7
0 5 10 15 20
Po
wer
(m
W/g
)
Time (hour)
GU GU-5-17µm GU-10-17µm GU-15-17µm
HE HE-5-17µm HE-10-17µm HE-15-17µma)
0
1
2
3
4
5
6
7
0 5 10 15 20
Po
wer
(m
W/g
)
Time (hour)
GU GU-5-12µm GU-10-12µm GU-15-12µm
HE HE-5-12µm HE-10-12µm HE-15-12µmb)
0
1
2
3
4
5
6
7
0 5 10 15 20
Po
wer
(m
W/g
)
Time (hour)
GU GU-5-3µm GU-10-3µm GU-15-3µm
HE HE-5-3µm HE-10-3µm HE-15-3µmc)
61
Figure 3.3: Effect of LF on the Total Energy Released for Pastes with a) 17µm LF, b)
12µm LF and c) 3 µm LF
0
50
100
150
200
250
0 5 10 15 20
Ener
gy (
J/g)
Time (hour)
GU GU-5-17µm GU-10-17µm GU-15-17µm
HE HE-5-17µm HE-10-17µm HE-15-17µma)
0
50
100
150
200
250
0 5 10 15 20
Ener
gy (
J/g)
Time (hour)
GU GU-5-12µm GU-10-12µm GU-15-12µm
HE HE-5-12µm HE-10-12µm HE-15-12µmb)
0
50
100
150
200
250
0 5 10 15 20
Ener
gy (
J/g)
Time (hour)
GU GU-5-3µm GU-10-3µm GU-15-3µmHE HE-5-3µm HE-10-3µm HE-15-3µm
c)
62
a) Hydration Peak
The influence of LF size and content on the hydration peak is presented in Figure 3.4. Each
point in the curve is the average of three tests and the corresponding coefficient of variation
was less than 3% for all mixes (please refer to Section A.6 in Appendix A for the raw data
and the statistical analysis). GU and HE mixes can be compared to the horizontal line
representing the control mixture (i.e., 100% GU and 100% HE). In all pastes made with
GU and HE cement, the maximum peak increased and occurred sooner with higher LF
content and smaller LF size compared to the corresponding control mix (i.e., 100% GU
and 100% HE). This is due to the acceleration effect of LF and agrees with the observations
reported in the literature [28,29].
Figure 3.4: Effect of LF Content and Size on the Hydration Peak
As shown in Figure 3.4, for paste made with GU cement and 5% LF, the increase in the
hydration peak was approximately 4% irrespective of LF size compared to the control mix
(i.e., 100% GU). Pastes made with 17µm and 12µm LF showed approximately similar
hydration peak regardless of LF content. However, LF content increased the hydration peak
in pastes made of 3µm LF. This is due to the greater surface area of 3µm compared to
3.5
4.0
4.5
5.0
5.5
6.0
6.5
17µm 12µm 3µm
Hyd
rati
on P
ow
er (
mW
/g)
LF Size
GU-5%LF GU-10%LF GU-15%LF
HE-5%LF HE-10%LF HE-15%LF
15%LF
10%LF
5%LF
15%LF
5%LF
10%LF
HE
GU
100%HE
100%GU
63
17µm and 12µm LF, which magnifies the acceleration effect of LF on the hydration
process. In pastes made of HE cement, LF of 3µm showed the highest hydration peak
followed by 12µm and 17µm LF. The increase in LF content increased the hydration peak
for all LF sizes. This indicates that the effect of LF on cement hydration can be enhanced
by the increase in cement fineness.
Figure 3.2 reveals that the hydration peaks in pastes made with GU cement were relatively
flat and extended to approximately 3.5 hours in contrast to the sharper peaks observed in
pastes made with HE cement. Second hydration peaks following sulfate depletion point
were more pronounced in GU and HE pastes made with 12μm and 3μm compared to pastes
made with 17μm as shown in Figure 3.2. This could be due to the acceleration in the
hydration reactions including the reaction of C3A and gypsum causing sooner sulfate
depletion point. Figure 3.4 reveals that pastes made with HE cement showed a greater
percentage increase in the hydration peak when LF was added compared to counterpart
pastes made with GU cement.
b) Total Energy Released
The total energy released from the time of water addition to 20 hours was measured for
each mix design and compared to the control mix without LF, as presented in Figure 3.5.
Each point in the curve is the average of three tests and the corresponding coefficient of
variation was less than 2% for all mixes (please refer to Section A.6 in Appendix A for the
raw data and the statistical analysis). The total energy released was calculated as the area
under the power-time curve presented in Figure 3.2. In all pastes, the total energy released
increased with higher LF content and smaller LF size compared to the corresponding
control mix (i.e., 100% GU and 100% HE).
Replacing GU or HE cement with LF increased the total energy released from the system
during the first 20 hours of hydration, which agrees with the observations obtained from
the literature [8]. The increase in the total energy released with LF is caused by the
acceleration in the hydration reactions [30]. The formation of calcium monocarboaluminate
that fills the pores between cement particles could also be a contributing factor [31,32].
As would be expected, pastes made of HE cement showed greater total heat released
compared to pastes made of GU cement. However, blending GU cement with 3µm LF
significantly increase the total heat released. The total heat released of this mix was greater
64
than the total heat released from paste made of 100% HE cement. This shows the important
role of LF fineness in enhancing the hydration rate of coarser cement (i.e., GU cement).
The total energy released after 20 hours of hydration for all pastes made with GU and HE
cements with and without LF ranged from 185 to 221 J/g. This range was reduced with
time as the total energy released after 72 hours of hydration for all pastes made with GU
and HE cements with and without LF ranged from 249 to 269 J/g. This is expected as pastes
made with finer cement (i.e., HE cement) or fine fillers (i.e., LF) showed higher early heat
of hydration than paste made with 100% GU. After approximately 13 hours, the heat of
hydration of pastes made with finer cement (i.e., HE cement) or fine fillers (i.e., LF) was
lower than the paste made with 100% GU, as presented in Figure 3.2.
Figure 3.5: Effect of LF Content and Size on the Total Energy Released after 20 Hours
3.3.1.3. Thermal Analysis
a) Ca(OH)2 Content
Figures 3.6 and 3.7 present the measured Ca(OH)2 content for pastes made with GU and
HE cement, respectively. Each point in the curve is the average of three tests and the
corresponding coefficient of variation was less than 3% for all mixes (please refer to
180
185
190
195
200
205
210
215
220
225
17µm 12µm 3µmTo
tal
Ener
gy R
elea
sed
aft
er 2
0 H
ours
(J
/g)
LF Size
GU-5%LF GU-10%LF GU-15%LF
HE-5%LF HE-10%LF HE-15%LF
15%LF
10%LF
5%LF
15%LF
5%LF10%LF
HE
GU
100% HE
100% GU
65
Section A.6 in Appendix A for the raw data and the statistical analysis). At 16 hours,
Increasing the content of LF increases the Ca(OH)2 content regardless of LF size. The
increase in Ca(OH)2 content can be explained by the increased heat of hydration in the
presence of LF, which increases the hydration products including Ca(OH)2.
Figure 3.6: Effect of LF Content and Size on Ca(OH)2 Content of GU Cement Paste
Figure 6 shows that the increase in LF content up to 10% increased the Ca(OH)2 content
in pastes made of GU cement at 16 hours compared to the control mix (i.e., 100% GU). No
increase in Ca(OH)2 content was observed when the LF content increased to 15%. This is
due to the dilution effect of LF, which was more pronounced at 28 days compared to 16
hours. At 28 days, no effect of LF was observed on Ca(OH)2 content up to 10% replacement
level. Increasing LF content from 10% to 15% caused a reduction in Ca(OH)2 content due
to the dilution effect. For pastes made of HE cement, the addition of 5% LF increased the
Ca(OH)2 content, as presented in Figure 7. Further increase in LF did not cause any
additional increase in Ca(OH)2 content. The dilution effect of LF was more pronounced in
pastes made of GU cement compared to HE cement.
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
5 10 15
Ca(
OH
) 2(%
)
LF Content (%)
GU-17µm GU-12µm GU-3µm
28 Days
16 Hours
100% GU
100% GU
66
.
Figure 3.7: Effect of LF Content and Size on Ca(OH)2 Content of HE Cement Paste
b) CaCO3 Content
Figures 3.8 and 3.9 present the effect of LF size and content on the reactivity of LF (the
difference between the initial and the final CaCO3 content) in pastes made with GU and
HE cement, respectively. Each column in the figures is the average of three tests and the
corresponding standard deviation was less than 0.19 wt% for all mixes (please refer to
Section A.6 in Appendix A for the raw data and the statistical analysis). The initial and
final CaCO3 calculations were made based on Equations 3.4 and 3.5, respectively. The
following is a calculation example for mix HE-15-3 at 28 days:
Initial CaCO3 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑜𝑓 𝐿𝐹 (𝑏𝑙𝑒𝑛𝑑𝑒𝑑+𝑖𝑛𝑡𝑒𝑟𝑔𝑟𝑜𝑢𝑛𝑑)
𝑇𝑜𝑡𝑎𝑙 𝑀𝑎𝑠𝑠 (𝑐𝑒𝑚𝑒𝑛𝑡+𝐿𝐹+𝑤𝑎𝑡𝑒𝑟)× 100
= 148×0.96+0.035×987
(987+148+365)× 100 = 11.77 wt%
Final CaCO3 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (680 − 800°C ) ×Molar Mass of CaCO3
Molar Mass of CO2
= 4.28%×100.09
44.01 = 9.73 wt%
Reacted LF (wt%) = 11.77 – 9.73 = 2.03 wt%
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
5 10 15
Ca(
OH
) 2(%
)
LF Content (%)
HE-17µm HE-12µm HE-3µm
28 Days
16 Hours
100% HE
100% HE
67
Reacted LF as Percentage of Total Available LF (%) = 2.03
11.77× 100= 17.3%
From Figures 3.8 and 3.9, it was observed that the reactivity of LF increases with higher
LF content and smaller LF size, which agrees with the literature [18,19]. However, the
increase in the cement fineness increases the rate of LF reaction. This can be observed in
Figures 3.8a and 3.9a as the percentage by weight of reacted LF was higher in HE pastes
compared to counterpart pastes made with GU cement at 16 hours. In addition, the
percentage of reacted LF in GU pastes at 16 hours was less than 20% of the reacted LF of
the same pastes at 28 days. This could be due to the decrease in LF solubility with the
increase in temperature (i.e., at 16 hours, the cement pastes were under steam curing
conditions while at 28 days, the pastes were at 23°C for approximately 27 days after steam
curing) [33]. On the other hand, in pastes made with HE cement and LF, the percentage of
reacted LF at 16 hours compared to 28 days was 14% in 17µm, 37% in 12µm and 58% in
3µm. This indicates that the cement fineness plays an important role in the rate of LF
reaction under steam curing conditions.
Figure 3.8: Effect of LF Content and Size on CaCO3 Content of GU Cement Paste
a)16 hours, b) 28 days
0.0
0.5
1.0
1.5
2.0
2.5
0 5 10 15
Rea
cted
LF
(w
t%)
Blended LF Content (%)
GU GU-17µm GU-12µm GU-3µma)
0.0
0.5
1.0
1.5
2.0
2.5
0 5 10 15
Rea
cted
LF
(w
t%)
Blended LF Content (%)
GU GU-17µm GU-12µm GU-3µmb)
68
Figure 3.9: Effect of LF Content and Size on CaCO3Content of HE Cement Paste a) 16
hours, b) 28 days
The percentage by weight of the reacted LF for each mix was converted to the reacted LF
as a percentage of the total available LF in the system, as presented in Table 3.5. At 16
hours, the percentage of reacted LF to the total available LF was limited to 4.2% in GU
pastes and 11.5% in HE pastes. At 28 days, the percentage of reacted LF to the total
available LF ranged from 5.0% to 23.4% in pastes made with GU cement and 9.5% to
34.0% in pastes made with HE cement. It is important to note that the results of reacted LF
as a percentage of the total available LF should be interpreted with caution as it reduces
with the increase in the total LF content in the system. For example, for pastes made with
HE cement and 3µm LF, at 28 days, the reactivity of LF increased from 1.43 wt% to 1.60
wt% to 2.03 wt% when the LF content increased from 5% to 10% to 15%, respectively.
However, the reacted LF as a percentage of the total available LF in the system was reduced
from 24.4% to 18.0% to 17.3% when the LF content increased from 5% to 10% to 15%,
respectively. This is due to the fact that increasing LF content will increase the initial
CaCO3 content and thus the reacted LF content is divided by a larger number. Therefore,
0.0
0.5
1.0
1.5
2.0
2.5
0 5 10 15
Rea
cted
LF
(w
t%)
Blended LF Content (%)
HE HE-17µm HE-12µm HE-3µma)
0.0
0.5
1.0
1.5
2.0
2.5
0 5 10 15
Rea
cted
LF
(w
t%)
Blended LF Content (%)
HE HE-17µm HE-12µm HE-3µmd)
69
the reactivity of LF as a percentage of the total available LF in the system should only be
used when comparing mixes with similar LF content.
Table 3.5: Reactivity of LF
# Mix ID
LF Reactivity
(wt%)
Reacted LF as Percentage of Total
Available LF in the System (%)
16 hours 28 days 16 hours 28 days
1 GU 0.00 0.14 0.0 7.8
2 GU-5-17µm 0.01 0.40 0.1 7.7
3 GU-10-17µm 0.07 1.19 0.8 14.3
4 GU-15-17µm 0.09 1.56 0.8 14.0
5 GU -5-12µm 0.01 0.26 0.1 5.0
6 GU-10-12µm 0.10 1.28 1.2 15.4
7 GU-15-12µm 0.14 1.18 1.2 10.5
8 GU-5-3µm 0.03 0.31 0.6 5.9
9 GU-10-3µm 0.17 1.94 2.0 23.4
10 GU-15-3µm 0.48 2.27 4.2 20.3
11 HE 0.05 0.96 2.1 34.0
12 HE-5-17µm 0.09 1.45 1.5 24.8
13 HE-10-17µm 0.31 1.12 3.4 12.6
14 HE-15-17µm 0.12 1.12 1.0 9.5
15 HE-5-12µm 0.34 1.52 5.7 26.0
16 HE-10-12µm 0.74 1.38 8.3 15.4
17 HE-15-12µm 0.60 1.64 5.1 14.0
18 HE-5-3µm 0.65 1.43 11.2 24.4
19 HE-10-3µm 0.94 1.60 10.6 18.0
20 HE-15-3µm 1.35 2.03 11.5 17.3
The LF reactivity results at 28 days presented in Figures 3.8 and 3.9 and Table 3.5 were in
agreement with other research work done under moist curing conditions where the reacted
LF as a percentage of the total available LF ranged from 11-32% at 28 days [13,34,35]. At
16 hours, where the samples have been exposed to high temperature (i.e., 55°C), the
reactivity of LF was limited due to the fact that the solubility of CaCO3 reduces with the
increase in temperature. It is expected that most of the LF chemical reaction will take place
after the end of steam curing when the temperature drops to ambient temperature (i.e.,
23°C).
70
c) Degree of Hydration
The results of the degree of hydration are presented in Figures 3.10 and 3.11. Each point
in the curve is the average of three tests and the corresponding coefficient of variation was
equal or less than 4% for all mixes (please refer to Section A.6 in Appendix A for the raw
data and the statistical analysis). For pastes made with HE cement, it is apparent that the
size of LF has a greater influence on the degree of hydration than LF content. However, in
pastes made with GU cement, the LF size and content had a similar effect on the degree of
hydration.
Based on the thermal analysis, LF had a greater impact on the Ca(OH)2 content, CaCO3
content and the degree of hydration in pastes made of HE cement compared to counterpart
pastes made of GU cement. This agrees with the results of the heat of hydration as pastes
made with HE cement showed a higher increase in hydration peak and total energy released
when LF was added compared to counterpart pastes made of GU cement.
Figure 3.10: Effect of LF Content and Size on the Degree of Hydration of Pastes at 16
Hours
0.60
0.61
0.62
0.63
0.64
0.65
0.66
0.67
0.68
0.69
0.70
5 10 15
Deg
ree
of
Hyd
rati
on
LF Content (%)
GU-17μm GU-12μm GU-3μm
HE-17μm HE-12μm HE-3μm
100% HE
100% GU
71
Figure 3.11: Effect of LF Content and Size on the Degree of Hydration of Pastes at 28
Days
3.3.1.4. Cube Compressive Strength
The results of the compressive strength testing are presented in Figures 3.12 to 3.14. Figure
3.12 presents the compressive strength of mortars made with 5% LF. Figures 3.13 and 3.14
present the compressive strength of mortars made with 10% and 15% LF, respectively.
Each compressive strength result is an average of three mortar cubes and the corresponding
coefficient of variation was less than 6% for all mixes (please refer to Section A.6 in
Appendix A for the raw data and the statistical analysis). Figures 3.12 to 3.14 reveals that
LF improves the compressive strength at 12 and 16 hours for HE cement mortars while no
effect of LF was observed with GU cement mortars compared to the corresponding control
mixes (i.e., 100% GU and 100% HE). However, at 3, 7 and 28 days, the effect of LF on
the compressive strength was different when comparing mortars made with GU to those
with HE cement. For GU cement mortars, LF yields a reduction in the compressive strength
after 7 days. On the contrary, the compressive strength of HE cement mortars increased
with the addition of LF at all ages (i.e., at 12 hours and 16 hours and at 3, 7 and 28 days).
0.80
0.81
0.82
0.83
0.84
0.85
0.86
0.87
0.88
0.89
0.90
5 10 15
Deg
ree
of
Hyd
rati
on
LF Content (%)
GU-17μm GU-12μm GU-3μm
HE-17μm HE-12μm HE-3μm
100% HE
100% GU
72
Figure 3.12: Effect of 5% LF on Cement Mortar Compressive Strength
Figure 3.13: Effect of 10% LF on Cement Mortar Compressive Strength
30
35
40
45
50
55
60
65
70
0.1 1 10 100
Cub
e S
tren
gth
(M
Pa)
Age (Days)
GU GU-5-17µm GU-5-12µm GU-5-3µm
HE HE-5-17µm HE-5-12µm HE-5-3µm
12 hrs. 16 hrs.
3 7 28
30
35
40
45
50
55
60
65
70
0.1 1 10 100
Cub
e S
tren
gth
(M
Pa)
Age (Days)
GU GU-10-17µm GU-10-12µm GU-10-3µm
HE HE-10-17µm HE-10-12µm HE-10-3µm
12 hrs. 16 hrs.
3 7 28
73
Figure 3.14: Effect of 15% LF on Cement Mortar Compressive Strength
For mortars made with GU cement, the effect of LF at 12 and 16 hours was less pronounced
compared to mortars made with HE cement. In general, no significant improvement in the
compressive strength was observed at 12 and 16 hours when LF was used with GU cement.
However, at later ages (i.e., 3, 7 and 28 days) the strength of mortars made with LF was
slightly lower (3 to 4%) than the control mix (i.e., 100% GU). The decrease in compressive
strength was greater in mortars made with higher content of LF.
Replacing 5% of HE cement did not cause any significant effect on the compressive
strength of mortar from 12 hours to 28 days, as presented in Figure 3.12. When the LF
content increased from 5% to 10%, the compressive strength of mortar was slightly
increased at all ages compared to the control mix (i.e., 100% HE). Greater compressive
strength was achieved when LF content increased from 10% to 15% compared to the
control mix (i.e., 100% HE). The effect of LF size was greater when LF content was 15%
compared to 5% and 10% LF content. The effect of LF on the compressive strength of
mortars made with HE cement was greater than in mortars made with GU cement. This
agrees with the heat of hydration and thermal analysis results. At 12 and 16 hours, the
improvement in the compressive strength of mortars made with LF can be attributed to the
30
35
40
45
50
55
60
65
70
0.1 1 10 100
Cub
e S
tren
gth
(M
Pa)
Age (Days)
GU GU-15-17µm GU-15-12µm GU-15-3µm
HE HE-15-17µm HE-15-12µm HE-15-3µm
12 hrs. 16 hrs.
3 7 28
74
acceleration of hydration and early production of monocarboaluminate especially in mix
designs made with HE cement.
3.3.2. Influence of Cement Fineness
The increase in cement fineness from 392 m2/kg in GU cement to 514 m2/kg in HE cement
decreased the initial setting time by 4%, as presented in Table 3.4. The hydration peak
values were approximately 40% higher in HE cement pastes made with and without LF
compared to counterpart pastes made with GU cement, as presented in Figure 3.4. The
increase in the cement fineness increases the surface area which in return increases the
hydration rate and thus reduces the initial setting time.
From Figures 3.6 and 3.7 it was observed that the Ca(OH)2 content at 16 hours was
approximately 3% higher in HE cement pastes made with or without LF compared to
counterpart pastes made with GU cement. At 28 days, the content of Ca(OH)2 was 5%
higher in HE cement pastes compared to pastes made with GU cement. Similar observation
was obtained from the degree of hydration results. This indicates that the increase in the
cement fineness can minimize the dilution effect at later age (i.e., 3 days to 28 days).
From Figures 3.8 and 3.9, it was observed that the reactivity of LF was faster in pastes
made with HE cement compared to counterpart pastes made with GU cement. HE pastes
showed greater LF reactivity compared to GU pastes at 16 hours. At 28 days, pastes made
of HE and GU cements showed similar LF reactivity. This indicates that the increase in
cement fineness can accelerate the chemical reaction of LF. Finer cement causes the sulfate
depletion point to occur sooner as shown in Figure 3.2. This allows the LF reaction to start
sooner as LF reaction occurs after the consumption of the initial calcium sulfate in the
system [14]. Comparing HE to GU pastes reveals that the presence of LF did not have any
influence on the effect of cement fineness on the initial setting time, heat of hydration,
Ca(OH)2 or the degree of hydration.
From Figures 3.12 to 3.14, it was observed that the average increase in the mortar
compressive strength at 12 and 16 hours with the use of LF was 24% greater in HE mortars
compared to GU mortars. However, this increase in the compressive strength of HE mortars
compared to GU cement mortars diminished with time (18%, 14% and 9% at 3, 7 and 28
days, respectively), which agrees with the findings of other studies [36,37,38].
75
3.3.3. Influence of Steam Curing Duration
For cement mortars made with GU cement, the compressive strength after 12 hours and 16
hours of steam curing was approximately 59% and 65% of the 28-day compressive
strength, respectively, as presented in Figures 3.12 to 3.14. For HE mortars, the
compressive strength after 12 hours and 16 hours of steam curing was 66% and 72% of the
28-day compressive strength, respectively, as presented in Figures 3.12 to 3.14. This
indicates that a significant portion of the 28-day strength was achieved after 12 hours of
steam curing and only an additional 6% of the 28-day strength was achieved when the
steam curing duration was extended from 12 hours to 16 hours.
3.3.4. Influence of Reacted Limestone Filler
To study the influence of LF reactivity, Figure 3.15 shows the relationship between the
total heat released and compressive strength measurements at 16 hours and the percentage
of reacted LF (wt%) at 16 hours. Figure 3.15 reveals that the increase in the total heat
released and the increase in the percentage of reacted LF at 16 hours increased the
compressive strength. This is due to the acceleration of the hydration process in the
presence of LF, which allows LF to react sooner after the sulfate depletion point and form
monocarboaluminate that fills the voids and increases the compressive strength.
The reactivity of LF at 16 hours plotted against the Ca(OH)2 content and the degree of
hydration measurements at 16 hours is presented in Figure 3.16. Each point in the figure is
the average value of three tests (please refer to Figure A.3 in Appendix A which presents
all the raw data). This figure reveals that the Ca(OH)2 content increases with the increase
in the percentage of reacted LF in the system up to 0.4 wt% of reacted LF. Following this
point, any increase in the amount of reacted LF decreased the Ca(OH)2 content. The
reduction in the Ca(OH)2 content was due to the dilution effect. On the other hand, the
degree of hydration increased with the increase in the percentage of reacted LF in the
system. The degree of hydration is expected to increase due to the acceleration in the
hydration process in the presence of LF and the production of monocarboaluminate. By
comparing the two regression curves in Figure 3.16, it can be observed that the increase in
the percentage of reacted LF compensates for the reduction in the Ca(OH)2 content due to
the dilution effect. This explains the increase in the degree of hydration even at a greater
percentage of reacted LF while Ca(OH)2 content was reduced. No correlation could be
76
established for the reactivity of LF (wt%) with the total heat released, compressive strength,
Ca(OH)2 content or the degree of hydration at 28 days.
Figure 3.15: Relationship between LF Reactivity, Cube Compressive Strength and Total
Heat Released and at 16 hours
Figure 3.16: Relationship between LF Reactivity, Ca(OH)2 Content and Degree of
Hydration at 16 hours
0
25
50
75
100
125
150
175
200
225
250
0
5
10
15
20
25
30
35
40
45
50
55
60
65
0.0 0.4 0.8 1.2 1.6
To
tal
Hea
t R
elea
sed
aft
er 1
6 h
rs.
(J/g
)
Cub
e C
om
pre
ssiv
e S
tren
gth
at
16
hrs
. (M
Pa)
LF Reactivity at 16 hrs. (wt%)
Cube Compressive Strength at 16 hrs. Total Heat Released after 16 hrs.
0.54
0.56
0.58
0.60
0.62
0.64
0.66
0.68
11.8
12.0
12.2
12.4
12.6
12.8
13.0
13.2
13.4
13.6
13.8
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
Deg
ree
of
Hyd
rati
on a
t 1
6 h
rs.
Ca(
OH
) 2C
onte
nt
at 1
6 h
rs.
(wt%
)
LF Reactivity at 16 hrs. (wt%)
Ca(OH)2 Content at 16 hrs. Degree of Hydration at 16 hrs.
R2 = 0.77
R2 = 0.71
77
3.3.5. Statistical Analysis
A multiple linear regression analysis was conducted and the value of the beta coefficient
for each independent variable (cement fineness, LF content, LF size, steam curing duration
and moist curing duration) was used to evaluate the influence each variable has on the
dependent variable (heat of hydration, reactivity of LF, degree of hydration and
compressive strength) [39]. The multiple linear regression analysis was conducted at a
confidence level of 95%. The data representing an independent variable were normalized.
The highest beta coefficient precedes the most influential independent variable. The results
of the statistical analysis are presented in Tables 3.6 and 3.7. Cement fineness was the most
influential variable on the heat of hydration and compressive strength while moist curing
duration was the most influential variable on LF reactivity and the degree of hydration. LF
content was the second most influential variable on the heat of hydration while LF size was
the second most influential variable on the degree of hydration. The statistical analysis
showed that the hydration kinetics and strength of steam cured cement pastes and mortars
made with LF were greatly influenced by the fineness of the cement.
Table 3.6: Multiple Linear Regression Analysis
Property Prediction Equation R2
Heat of
Hydration
Hydration Peak Value (mW
g)
= 8.53 × C + 0.62 × LFC − 0.22 × LFS − 3.11
0.98
LF Reactivity Reacted LF(wt%) = 2.71 ∙ C + 1.25 ∙ LFC − 0.46 ∙ LFS + 3.31 ∙ Am − 2.45 0.83
Degree of
Hydration DOH = 8.82 × 10−3 ∙ C + 1.38 × 10−3 ∙ LFC − 1.16 × 10−2 ∙ LFS
+0.187 ∙ Am + 0.66 0.99
Early Age
Compressive
Strength (12 and
16 hrs.)
Early Age (12 and 16 hours) Strength (MPa) = 46.35 × C + 0.89 × LFC + 0.14 × LFS + 15.8 × As
− 15.21
0.93
Later Age
Compressive
Strength (3, 7
and 28 days)
Later Age (3, 7 and 28 days) Strength (Mpa)
= 41.78 × C + 0.16 × LFC − 1.91 × LFS + 15.19 × Am + 11.13 0.93
Where:
C: cement fineness coefficient = 𝐵𝑙𝑎𝑖𝑛𝑒 𝐹𝑖𝑛𝑒𝑛𝑒𝑠𝑠 (
𝑚2
𝑘𝑔)
514 (i.e., for GU = 0.81 and HE =1.00)
LFContent: blended LF content coefficient = 𝐿𝐹 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 (%)
15
LFSize : blended LF size coefficient = 𝐿𝐹 𝑠𝑖𝑧𝑒 (µ𝑚)
17
As: steam curing period coefficient = steam curing period (ℎ𝑜𝑢𝑟𝑠)
16
Am: moist curing period coefficient = moist curing period (𝑑𝑎𝑦𝑠)
28
78
Table 3.7: Controlling Variables of Mortars and Pastes Mix Designs
Property Controlling Variables
(1= highest influence , 3= lowest influence) 1 2 3
Heat of Hydration Cement
Fineness LFContent LFSize
LF Reactivity Moist Curing
Duration Cement
Fineness LFContent
Degree of Hydration Moist Curing
Duration LFSize
Cement
Fineness Early Age Compressive
Strength (12 and 16 hours) Cement
Fineness Steam Curing
Duration LFContent
Later Age Compressive
Strength (3, 7 and 28 days) Cement
Fineness Moist Curing
Duration LFSize
3.4. Conclusions
Based on the results of this chapter, the following conclusions can be drawn:
(i) The results of the isothermal calorimetry, thermal analysis and compressive
strength showed an improved early age hydration and compressive strength at 12
and 16 hours with finer limestone filler and cement (i.e., HE cement). This
improvement was more pronounced with greater limestone filler content (i.e., 15%)
and greater fineness (i.e., 3µm limestone filler). Increasing cement fineness in HE
cement compared to GU cement increases the acceleration effect of limestone filler
on the hydration process. The finer cement particles in HE cement allow more
cement to hydrate sooner and thus magnify the acceleration effect of limestone
filler on the hydration process.
(ii) The reactivity of limestone filler was found to be limited to 34% of the total
limestone filler available in the mix and depends mainly on the fineness of
limestone filler and cement fineness. The increase in limestone filler fineness
increased the total reacted limestone filler while the increase in cement fineness
increased the rate of the limestone filler reaction. The reactivity of limestone filler
had an important role in reducing the dilution effect.
(iii) The degree of hydration increased with an increase in cement fineness from 392
m2/kg to 514 m2/kg, at 16 hours. However, increasing cement fineness did not
significantly influence the degree of hydration at 28 days. Moist curing duration
79
and the fineness of limestone filler were the most influential variables on the degree
of hydration.
(iv) At higher limestone filler contents (i.e., 10% and 15%) the dilution effect at later
age (i.e., 3, 7 and 28 days) was reduced by increasing the fineness of the cement
(i.e., using HE cement).
(v) Statistical analysis showed that the hydration kinetics of cement pastes and the
compressive strength of mortars made with limestone filler were greatly influenced
by the fineness of the cement.
3.5. Acknowledgments
This research was supported by the Ministry of Transportation of Ontario. Opinions
expressed in this thesis are those of the authors and may not necessarily reflect the views
and policies of the Ministry of Transportation of Ontario. The authors would like to
acknowledge Holcim Canada for providing the cement, Omya Canada for providing the
limestone and Dufferin Aggregates for providing the fine aggregates.
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Powder on Microstructure and Strength of Ultra-High Performance Cement-Based
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[32] Heikal, M., El-Didamony, H., and Morsy, M. (2000). Limestone-filled Pozzolanic
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83
Chapter 4 - Effect of Cement and Limestone Particle Size on the Durability of Steam Cured Self-Consolidating Concrete
Abstract
This chapter describes a laboratory program to investigate the influence of cement and
limestone filler particle size on the hardened properties and durability performance of
steam cured self-consolidating concrete. In addition, the interplay between cement type
and limestone filler particle size was investigated. CSA type GU and HE cements were
used with 5% silica fume. The water-to-cement ratio was 0.34. Limestone filler with two
nominal particle sizes of 17µm and 3µm, which correspond to Blaine finenesses of 475
and 1125 m2/kg, respectively, were used. In addition to plastic concrete properties,
hardened properties including compressive strength, elastic modulus, ultrasonic pulse
velocity and density were measured at 12 and 16 hours and at 3, 7 and 28 days. Durability
performance including rapid chloride permeability testing, sulfate resistance, linear
shrinkage, salt scaling resistance and freeze-thaw resistance were evaluated. The results
showed that limestone filler improved the 12 and 16 hour strength with no influence on
later age strength (3 to 28 days). The linear shrinkage and rapid chloride permeability
decreased with the addition of limestone filler. This reduction was linked to the production
of calcium monocarboaluminate. Limestone filler did not impact the sulfate resistance, salt
scaling resistance or freeze-thaw resistance of concrete.
Keywords: limestone filler, self-consolidating concrete, calcium monocarboaluminate,
compressive strength, durability
84
4.1. Introduction
Self-consolidating concrete (SCC) has been proven to have several benefits for the
construction industry including i) eliminate the need for surface finishing, ii) decrease the
casting time and iii) reduce noise exposure and congestion at the casting place [1,2]. These
advantages are beneficial for precast/prestressed applications where maintaining
production schedule is critical. However, SCC has a higher cost compared to traditional
concrete due to the higher cement content, the use of various chemical admixtures, and the
increased formwork pressure [3,4]. Furthermore, SCC is usually made with a water-to-
cement ratio of 0.32 to 0.36, which increases the portion of the cement that remains
unhydrated. The unhydrated cement acts as an expensive filler [5]. In addition, the volume
of fine and coarse aggregates in SCC is 6% to 10% lower compared to traditional concrete
[1,3,5]. This means that SCC requires 6% to 10% higher paste volume compared to
traditional concrete to coat the aggregates and fill the voids between aggregate particles.
Since cement paste acts as a lubricant for the concrete, coating the aggregates has a direct
impact on concrete workability. Filling the voids between aggregate particles with cement
paste reduces the entrapped air voids and thus improves the strength and durability of the
concrete. The higher paste volume in SCC reduces the volume stability and increases the
risk of cracking [6]. This is due to the fact that the concrete expansion and contraction is
caused only by the cement paste fraction of concrete [6]. Therefore, SCC should be
designed to achieve the required strength with the minimum amount of cement paste to
ensure volume stability.
One approach to address the higher amount of cement and cement paste content in SCC is
by replacing the cement with a filler material such as limestone filler (LF). The filler
material reduces the voids between aggregate particles and thus reduces the required
amount of cement paste. This approach has been proven to reduce the cost as well as the
negative environmental impact of the concrete [7,8,9].
The effect of LF on the durability performance of SCC has been the focus of many research
efforts. Findings have shown that LF can improve the transport properties and volume
stability due to improved packing density and the production of calcium
monocarboaluminate [10,11,12]. However, these studies were conducted under normal
curing conditions (i.e., at 23°C and 90-100% RH) while the information available on the
influence of LF on the durability performance of steam cured SCC is limited. Due to the
85
elevated steam curing temperature, the hydration rate is accelerated. In addition, the
increase in the temperature reduces the solubility of LF [13], which can influence the
interaction between LF and cementing materials and have implications on the hardened
properties of concrete.
LF is often categorized by the LF producers and the construction industry using particle
size [11,14]. The available data in the literature showed that the decrease in LF particle size
increases the heat of hydration and the early age strength gain while reducing the bleeding
and the early age volume change [14,15,16]. These effects can be beneficial to
precast/prestressed applications where high early strength is required. Furthermore, in
precast/prestressed applications, both GU and HE cements are commonly used. Therefore,
understanding the role of particle size of both LF and cement and how they interact and
impact the strength and durability of concrete is critical to ensure high early strength
without impacting long-term durability performance.
The aim of this chapter is to examine the influence of particle size of LF and cement on
plastic properties, hardened properties and durability performance of steam cured SCC.
This will be achieved by evaluating the influence of particle size of LF and cement on the
hydration kinetics, plastic, hardened and transport properties, and durability performance
of steam cured SCC. CSA general use (Type GU) and high early strength (Type HE)
cements were selected to represent the common cements used in the precast/prestressed
applications in Canada. The Blaine fineness of GU and HE cement were 392 and 514
m2/kg, respectively. LF, with two nominal particle sizes of 17µm and 3µm which
correspond to Blaine finenesses of 475 and 1125 m2/kg, respectively, was used. Steam
curing was conducted at a maximum temperature of 55°C to prevent any alteration in the
microstructure of concrete due to delayed ettringite formation [17]. Hydration kinetics and
phase composition of cement pastes were evaluated using the heat of hydration and
Thermal Gravimetric Analysis and Differential Thermal Analysis (TG/DTA). Mortar
strength evolution was measured from 12 hours to 28 days. Plastic properties of SCC
including slump flow, T50, J-ring, visual stability index (VSI), L-box and column
segregation were measured. Hardened properties including compressive strength, elastic
modulus, ultrasonic pulse velocity (UPV) and density were measured at 12 and 16 hours
and at 3, 7 and 28 days. The transport properties were evaluated using rapid chloride
permeability test (RCPT) at 28 days. The durability performance of SCC was evaluated
86
using sulfate resistance, linear shrinkage, salt scaling resistance and freeze-thaw resistance.
A multiple linear regression analysis was conducted to identify the primary variables that
control the hardened and transport properties of concrete mixtures.
4.2. Experimental Program
4.2.1. Materials
Two types of cements, CSA Type GU and HE with Blaine fineness of 392 and 514 m2/kg,
respectively, were used, which represent the commonly used cements in
precast/prestressed applications. The cements were supplied by Holcim Canada. The
chemical and physical properties of the GU and HE cements are presented in Table 4.1.
The interground limestone content in GU and HE cement was 2.5 and 3.5%, respectively.
The silica fume (SF) used was an undensified powder, from the production of silicon metal,
supplied by SKW Canada. Two LFs were used with nominal particle sizes of 17µm and
3µm which correspond to Blaine fineness of 475 and 1125 m2/kg, respectively. LF was
supplied by Omya Canada. The chemical and the physical properties of LF are presented
in Table 4.2. The fine aggregate was natural sand with a specific gravity of 2.72 and a
fineness modulus of 2.84. The coarse aggregate was crushed limestone with a maximum
size of 13 mm. The coarse aggregate was washed with water before using it in concrete to
eliminate any contamination or fine particles. The sand and coarse aggregate were supplied
by Dufferin Aggregates. Two admixtures supplied by Euclid Chemical Company, Canada
were used; high-range water reducer (HRWR) (Plastol 6400) and air-entraining admixture
(AEA) (Airex-L).
4.2.2. Mix Design
The details for six SCC mix designs are given in Table 4.3 and the corresponding mixture
proportions are presented in Table 4.4. The SCC mixes were designed to achieve a
minimum compressive strength of 44 MPa in 16 hours to represent the current practice in
the precast/prestressed applications in Canada. Due to the high early age strength
requirement, all SCC mixes were designed with 5% SF and w/c of 0.34. The sand-to-total
aggregate ratio (S/A) were kept constant at 0.47. All concrete mixes were designed with
5% fresh air content. The CSA A23.1-14 sets the fresh air content based on the maximum
aggregate size in concrete. For concrete made with a maximum aggregate size of 10 mm,
the required fresh air content is 6 to 9%. Concrete made of aggregate with a maximum
87
aggregate size of 14 to 20 mm requires 5 to 8% fresh air content. Since the maximum
aggregate size used in this thesis was 13 mm, the fresh air content in all concrete mixes
was set to 5%. Although LF was used as a cement replacement, LF was not considered as
a cementitious material in water-to-cement ratio calculation.
For each mix design, concrete, mortar and paste specimens were prepared. The paste
specimens were used for the heat of hydration measurements and thermal analysis. Mortar
specimens were used to evaluate the strength evolution from 12 hours to 28 days. In the
paste and mortar specimens, no admixtures were used, to minimize variation in the results
due to admixture dosages.
Table 4.1: Chemical and Physical Properties of Cements and SF
Chemical and Physical Properties Cement Type
SF GU HE
SiO2 (%) 19.25 19.10 92.1
Al2O3 (%) 5.33 5.18 0.30
Fe2O3 (%) 2.41 2.35 0.60
CaO (%) 62.78 61.60 0.80
MgO (%) 2.36 2.35 0.70
SO3 (%) 4.01 4.26 0.20
Na2Oeq (%) 0.99 1.01 0.92
C3S (%) 58.55 55.15 ---
C3A (%) 10.04 9.75 ---
C4AF (%) 7.34 7.14 ---
C2S (%) 11.03 13.18 ---
LOI at 1150 °C (%) 2.27 2.10 2.00
Blaine (m2/kg) 392 514 ---
Limestone Content (CaCO3) 2.50 3.50 ---
Table 4.2: Chemical and Physical Properties of LF
Chemical and Physical Properties LF Size
17µm 3µm
LOI at 1050°C (%) 42.8 42.4
CaCO3 (%) 95.0 96.0
MgCO3 (%) 2.0 2.0
% Retained on 44μm mesh 15.000 0.003
Moisture Loss at 110°C (%) 0.03 0.08
Blaine (m2/kg) 475 1125
Specific Gravity 2.7 2.7
88
Table 4.3: Concrete Mix Details
MIX ID
Cementitious Materials LF
w/c Cement SF
(%)
Interground
(%)
Blended
Type % % Size
GU CSA Type
GU
95 5 2.5 0 --- 0.34
GU-17µm 80 5 2.5 15 17 0.34
GU-3µm 80 5 2.5 15 3 0.34
HE CSA Type
HE
95 5 3.5 0 --- 0.34
HE-17µm 80 5 3.5 15 17 0.34
HE-3µm 80 5 3.5 15 3 0.34
Table 4.4: Weight Proportions of Concrete Mixes
Mix ID Cement SF
LF Coarse
Agg. Water Sand/
Aggregate
AEA HRWR Size
(μm) kg/m3
kg/m3 kg/m3 ml/100kg
GU 427.5 22.5 --- --- 950 150.3 0.47 37 900
GU-17µm 360 22.5 17 67.5 950 123.0 0.47 120 2300
GU-3µm 360 22.5 3 67.5 950 123.0 0.47 148 2450
HE 427.5 22.5 --- --- 950 150.3 0.47 45 1000
HE-17µm 360 22.5 17 67.5 950 123.0 0.47 195 2350
HE-3µm 360 22.5 3 67.5 950 123.0 0.47 240 2500
4.2.3. Mixing and Curing
Mortars and pastes were prepared by blending cement, sand and LF (when used) for 2
minutes in a 10-litre mortar mixer followed by the addition of water and mixing for 4
minutes. Concrete mixing was done in a 30-litre drum mixer. Each SCC mix design was
prepared in two 30-litre batches. SCC mixes were prepared by blending coarse aggregate
and sand with 80% of water for 1 minute followed by the addition of cement and the
remaining 20% of water containing AEA and mixing for 3 minutes. Following that, HRWR
was added and the concrete was mixed for an additional 4 minutes.
The curing regime consisted of steam curing for 12 or 16 hours at a maximum holding
temperature of 55°C and 95% relative humidity (RH) followed by moist curing at 100%
RH and 23°C. The steam curing was conducted in a 0.45 m3 environmental chamber
manufactured by Cincinnati Sub-Zero with a built-in steam generator to control the relative
89
humidity. To prevent any thermal damage due to the early application of steam curing,
initial setting time for each mix was measured [18]. The steam curing was applied after the
initial setting time (preset period of 2 hours at 23°C and 95% RH). The steam curing
regimes are presented in Figure 4.1. After the 2-hour preset period, all specimens were
steam cured in the following sequence:
i. heating to 55°C in 2 hours (16°C /hour) while maintaining 95%RH
ii. holding the temperature at 55°C while maintaining 95%RH for 10 hours for the
16-hour curing regime or 6 hours for the 12-hour curing regime.
iii. cooling to 23°C in 2 hours (16°C /hour) while maintaining 95%RH (in the
chamber)
The temperature of the chamber was controlled to maintain the required internal
temperature of the samples, using Type T thermocouples embedded in the samples at the
centroid. This was to ensure that the internal temperature of the specimens was following
the steam curing regime presented in Figure 4.1.
Figure 4.1: Steam Curing Regimes
10
15
20
25
30
35
40
45
50
55
60
0 2 4 6 8 10 12 14 16
Tem
per
ature
(°C
)
Time (hour)
12-hour steam curing regime
16-hour steam curing regime
90
4.2.4. Test Methods
4.2.4.1. Mortar and Paste Testing
Normal Consistency and Initial Setting Time: The normal consistency and initial setting
time were measured according to ASTM C187-11 and ASTM C191-08, respectively.
Heat of Hydration: The heat of hydration was measured for 72 hours at 23°C using a TAM
Air isothermal calorimeter manufactured by Thermometric in accordance with ASTM
C1702-09 Method B. For each mix design, three paste samples were tested.
Thermal Analysis: The TG/DTA analysis was conducted using SA Simultaneous Thermal
Analyzer heated to 1145°C at a heating rate of 10°C/min. For each mix design, three
TG/DTA tests were conducted. The paste specimens were tested after 16 hours of steam
curing and after 28 days (16 hours of steam curing followed by moist curing in limewater
until 28 days). Before testing, the specimens were freeze-dried. The freeze-drying
consisted of two steps. Firstly, the specimens were placed in liquid nitrogen to stop the
hydration reactions. Secondly, the specimens were placed under vacuum at -10°C. The
freeze-drying of the specimens continued until a constant mass (less than 0.1% change in
a 24-hour period) was achieved. The mass of the tested samples for all mix designs was
kept constant at 100 ± 0.4 mg. The calcium hydroxide (Ca(OH)2), calcium carbonate
(CaCO3) and the non-evaporable water contents were measured. The non-evaporable water
content was used to calculate the degree of hydration. The Ca(OH)2 content and the degree
of hydration were used to evaluate the hydration products to provide a relative comparison
between mix designs. CaCO3 content was used to evaluate the reactivity of LF. The initial
content (prior to mixing) of CaCO3 was calculated according to Equation 4.1. The
percentage by weight (wt%) of Ca(OH)2 and CaCO3 were calculated using stoichiometry
[19]. The mass loss due to the decomposition of CaCO3 between 680 to 800°C was used
to calculate the final CaCO3 content, as presented in Equation 4.2 [23]. The mass loss due
to Ca(OH)2 decomposition between 450 to 500°C was used to calculate the wt% of
Ca(OH)2, as presented in Equation 4.3 [20]. The difference between the initial and the final
CaCO3 content was assumed to be the portion of LF that was consumed in the reaction
with monosulfate and aluminate phases in the hydrated cement to form calcium
monocarboaluminate [21,22]. The degree of hydration was calculated by dividing the mass
91
loss between 23°C and 550°C by the maximum theoretical non-evaporable water (i.e.,
0.23), as presented in Equation 4.4 [23,24].
Initial CaCO3 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑜𝑓 𝐿𝐹
𝑇𝑜𝑡𝑎𝑙 𝑀𝑎𝑠𝑠 (𝑐𝑒𝑚𝑒𝑛𝑡+𝐿𝐹+𝑤𝑎𝑡𝑒𝑟)× 100 Eq. 4.1
Final CaCO3 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (680 − 800°C ) ×Molar Mass of CaCO3
Molar Mass of CO2 Eq.4.2
Ca(OH)2 Content (wt%) = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (450 − 500°C ) ×Molar Mass of Ca(OH)2
Molar Mass of H2O Eq.4.3
Degree of Hydration = 𝑀𝑎𝑠𝑠 𝑙𝑜𝑠𝑠 (23−550°C )
0.23 Eq.4.4
Mortar Compressive Strength: The cube compressive strength of mortar was measured in
accordance with ASTM C109-12. For each mix design, three cubes were tested at 12 hours
and 16 hours and at 3, 7 and 28 days.
4.2.4.2. Concrete Testing
Plastic Properties: The slump flow, T-50 and VSI were measured according to CSA A23.2
[25]. The J-ring and column segregation tests were conducted in accordance with ASTM
C1621-09 (CSA A23.2-20C) and ASTM C1610-10, respectively. The L-box was measured
in accordance with (MTO LS-440) [26]. The fresh air content was measured according to
ASTM C231-10 (CSA A23.2-4C).
Hardened Properties: The hardened properties were measured using 100 mm × 200 mm
cylinders according to CSA A23.2-3C. The compressive strength (CSA A23.2-9C), UPV
(ASTM C597-09), elastic modulus (ASTM C469-04) and density (ASTM C138-10) were
measured at 12 and 16 hours and at 3, 7 and 28 days.
Transport Properties: The transport properties were evaluated using RCPT at 28 days in
accordance with ASTM C 1202-10.
Durability Performance: The linear shrinkage was measured according to MTO LS-435
[26]. In this test, following steam curing, concrete prisms (75 mm × 75 mm × 285 mm)
were cured in limewater at 23°C for 7 days before exposure to 50% RH at 23°C. Sulfate
resistance was evaluated using ASTM C1012-10. The rapid freeze-thaw test was conducted
in accordance with ASTM C666-08. Salt scaling test was conducted in accordance with
MTO LS-412 [26]. In this test, at the end of steam curing, concrete slabs (300 × 300 × 75
92
mm) were moist cured (98% RH at 23°C) for 14 days followed by air curing (45-55% RH
at 23°C) for another 14 days. At the end of the 28 days, the concrete slabs were exposed to
50 freeze-thaw cycles. Each cycle consists of 16 hours at -18°C followed by 8 hours at
23°C and 50% RH.
4.3. Results and Discussion
4.3.1. Normal Consistency and Initial Setting Time
The results of the normal consistency and the initial setting time are presented in Table 4.5.
In general, the increase in cement fineness observed when comparing GU versus HE mixes
increased the normal consistency irrespective of the presence or fineness of LF. The
amount of water required to achieve normal consistency increased with the addition of LF.
Pastes made with 3µm LF showed a slight increase in the normal consistency compared to
pastes made with 17µm LF. The increase in the normal consistency with finer cement (i.e.,
HE cement) or finer LF was caused by the higher surface area, which increases the required
amount of water to achieve normal consistency.
Table 4.5: Normal Consistency and Initial Setting Time
MIX ID Normal
Consistency
Initial Setting
(mins)
Reduction in Initial Setting
Time* (%)
GU 0.280 94 ---
GU-17µm 0.305 91 3.2
GU-3µm 0.310 81 13.8
HE 0.330 91 3.2
HE-17µm 0.350 89 5.3
HE-3µm 0.355 77 18.1
*Compared to Mix GU
The increase in cement fineness decreased the initial setting time. The addition of LF
decreased the initial setting time for both GU and HE cement pastes. The influence of LF
on the initial setting time was greater in HE cement compared to GU cement. The effect of
LF fineness was more pronounced in the results of the initial setting time compared to the
normal consistency results. Pastes made with 3µm LF showed 12% decrease in the initial
setting time compared to pastes made with 17µm LF. The reduction in the initial setting
93
time with finer cement (i.e., HE cement) or finer LF was caused by the higher surface area,
which accelerates the hydration reactions causing a shorter initial setting time [27]. The
reduction in the initial setting time with the use of HE cement or finer LF reduces the risk
of thermal cracking due to steam curing as the concrete obtains the strength sooner
compared to concrete made with GU cement without LF.
4.3.2. Heat of Hydration
The heat of hydration curves of cement pastes are presented in Figure 4.2. Pastes made
with HE cement showed 40% higher hydration peak compared to counterpart pastes made
with GU cement. This was due to the higher fineness in HE cement, which increases the
hydration rate [28]. Pastes made of GU and HE cement with LF showed higher hydration
peaks compared to the corresponding 100% GU and 100% HE. For pastes made with GU
cement, the addition of LF increased the hydration peak from 4.6 mW/g in mix GU to 4.9
mW/g in mix GU-17µm and 5.1 mW/g in mix GU-3µm. This corresponds to 8% and 13%
increases in the hydration peak when GU cement was replaced by 17µm and 3µm LF,
respectively. For pastes made with HE cement, the addition of LF increased the hydration
peak from 6.1 mW/g in mix HE to 6.7 mW/g in mix HE-17µm and 7.4 mW/g in mix HE-
3µm. This corresponds to an increase of 9% and 21% when HE cement was replaced by
17µm and 3µm LF, respectively. Finer LF (i.e., 3µm) yielded greater heat of hydration
compared to coarser LF (i.e., 17µm). LF size of 3µm showed 4% and 10% higher hydration
peak compared to 17µm LF in GU and HE pastes, respectively. The results indicate that
LF had a greater influence on the heat of hydration in pastes made with HE cement
compared to counterpart pastes made with GU cement. This could be due to the higher
fineness of HE cement compared to GU cement, which reduces the space between cement
particles and allows better utilization of the surface area provided by LF for the
precipitation of hydration products.
94
Figure 4.2: Heat of Hydration of Cement Pastes at 23°C
4.3.3. Thermal Analysis
Ca(OH)2 content: The Ca(OH)2 content measurements are presented in Figure 4.3 (please
refer to Section A.7.1 in Appendix A for the raw data and the statistical analysis). Pastes
made with HE cement showed lower Ca(OH)2 content compared to counterpart pastes
made with GU cement. However, the difference in Ca(OH)2 content between pastes made
with HE and GU cement was greater at 16 hours compared to 28 days. The increase in the
cement fineness in HE cement increases the hydration rate, which allows more Ca(OH)2 to
be available for the pozzolanic reaction with SF. The addition of LF reduced the Ca(OH)2
content for pastes made of GU and HE cement at 16 hours and 28 days. The reduction in
the Ca(OH)2 content with the addition of LF was greater at 16 hours compared to the 28-
day results. The increases in the hydration rate due to the addition of LF increases the
hydration product, which allows more Ca(OH)2 to be consumed sooner in the pozzolanic
reaction with SF. Pastes made with 3µm LF showed 5% lower Ca(OH)2 content compared
to counterpart pastes made with 17µm LF regardless of cement fineness or age. Due to the
high fineness and amorphous structure of SF, the pozzolanic reaction is expected to take
place at the early age of hydration. However, it is mainly controlled by the availability of
0
1
2
3
4
5
6
7
8
0 5 10 15 20
Po
wer
(m
W/g
)
Time (Hour)
GU GU-17µm GU-3µmHE HE-17µm HE-3µm
95
Ca(OH)2 [29]. This explains the greater influence of LF content and cement fineness on the
Ca(OH)2 content at 16 hours compared to the 28-day measurement.
Figure 4.3: Effect of LF Content and Size on Ca(OH)2 Content of Pastes Made with GU
and HE Cements at 16 hours and 28 days
CaCO3 content: The percentage by weight of reacted LF at 16 hours and 28 days is
presented in Figure 4.4 (please refer to Section A.7.1 in Appendix A for the raw data and
the statistical analysis). Pastes made with GU and HE cement showed similar LF reactivity
at 16 hours. At 28 days, the reactivity of LF was slightly higher in pastes made with HE
cement compared to counterpart pastes made with GU cement. At all ages, the highest
reactivity was observed in mix designs made of GU and HE cement with 3µm LF. For all
mix designs, the percentage by weight of reacted LF at 16 hours was approximately half
of the percentage of reacted LF at 28 days. The 16-hour testing was conducted immediately
after steam curing, during which the samples were exposed to a higher temperature at 55°C.
At that temperature, the solubility of LF is reduced compared to 23°C [16]. The reduction
in LF solubility reduces the amount of reacted LF at 16 hours.
6.8
7.0
7.2
7.4
7.6
7.8
8.0
8.2
8.4
8.6
0% Blended LF 15% of 17µm LF 15% of 3µm LF
Ca(
OH
) 2 (
%)
GU-16 Hours HE- 16 Hours GU- 28 Days HE-28 Days
96
Figure 4.4: Effect of LF Content and Size on CaCO3 Content of Pastes Made with GU
and HE Cements a) 16 hours, b) 28 days
Degree of hydration: The degree of hydration results are presented in Figure 4.5 (please
refer to Section A.7.1 in Appendix A for the raw data and the statistical analysis). Pastes
made of HE cement showed a 25% higher degree of hydration compared to counterpart
pastes made of GU cement at 16 hours and 28 days. The higher degree of hydration
observed in HE cement was due to the acceleration in hydration rate at 16 hours. At 28
days, the higher degree of hydration observed with HE cement could be due to the increase
in the surface area in HE cement compared to GU cement. The higher surface area reduces
the thickness of hydration products coating anhydrous cement particles causing a higher
degree of hydration [30]. Although there was a clear effect of LF on the heat of hydration,
Ca(OH)2 content and calcium monocarboaluminate contents, LF content and fineness did
not influence the degree of hydration at 16 hours or 28 days. This could be due to two
factors. Firstly, the increase in hydration rate due to the additional surface area of LF was
-0.5
0.0
0.5
1.0
1.5
2.0
0% Blended LF 15% of 17µm LF 15% of 3µm LF
Rea
cted
LF
(w
t%)
GU HEa)
0.0
0.5
1.0
1.5
2.0
0% Blended LF 15% of 17µm LF 15% of 3µm LF
Rea
cted
LF
(w
t%)
GU HEb)
97
mainly observed in the first 8 to 10 hours, after which the hydration rate of LF pastes was
lower than paste made without LF as shown in Figure 4.2. Secondly, the reduction in the
cement hydration products “the dilution effect” with LF was compensated for by calcium
monocarboaluminate.
Figure 4.5: Effect of LF Content and Size on the Degree of Hydration of Cement Pastes
4.3.4. Mortar Compressive Strength
The results of the mortar compressive strength are presented in Figure 4.6. Each
compressive strength result is an average of three mortar cubes and the corresponding
coefficient of variation was less than 6% for all mixes (please refer to Section A.7.1 in
Appendix A for the raw data and the statistical analysis). Mortar made with 100% HE
showed greater compressive strength compared to 100%GU at early age (i.e., 12 and 16
hours) as would be expected. At 28 days, the strength of HE and GU mortars was similar.
Mortars made with LF showed higher compressive strength compared to counterpart
mortars made without LF at all ages. This can be explained by the increase in the hydration
rate observed in the heat of hydration results, which increases the early age strength again.
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0% Blended LF 15% of 17µm LF 15% of 3µm LF
DO
H
GU-16 Hours HE-16 Hours GU-28 Days HE-28 Days
98
However, the gain in the compressive strength with the addition of LF diminished with
time due to the dilution effect [31]. For example, the range of compressive strength for all
mix designs was 54 to 63 MPa at 12 hours and 80 to 84 MPa at 28 days. Further analysis
of the results reveals that the increase in the compressive strength with the addition of LF
was greater in mortars made with GU cement compared to counterpart mortars made with
HE cement. This could be due to the fact that GU cement was coarser than HE cement.
Therefore, the improvement in particle packing was expected to be higher in GU cement
compared to HE cement when LF was added [32]. Mortars made with 3µm LF showed
higher compressive strength from 12 hours to 7 days compared to 17µm LF regardless of
cement fineness. At 28 days, the compressive strength of mortars made with 3µm and
17µm LF was similar.
Based on the results of the heat of hydration, thermal analysis and mortar compressive
strength, the addition of LF improves the hydration kinetics at early age (i.e., 12 and 16
hours) and compressive strength from 12 hours to 28 days. This was due to the increase in
surface area, improved particle packing and the production of calcium
monocarboaluminate.
Figure 4.6: Cube Compressive Strength of Mortars
50
55
60
65
70
75
80
85
0.1 1 10 100
Cub
e C
om
pre
ssiv
e S
tren
gth
(M
Pa)
Age (Days) - Log Scale
GU GU-17µm GU-3µm
HE HE-17µm HE-3µm
12 hrs. 16 hrs.
3 7 28
99
4.3.5. Plastic Properties of Concrete
The plastic properties of concrete are presented in Table 4.6. All concrete mix designs had
a fresh air content of 5 to 5.6% and slump flow of 650 to 680 mm. In addition, all concrete
mix designs showed high stability with VSI ranging from 0 to 0.5 and column segregation
measurements below 3%. The yield of all concrete mixes was approximately 1.0 m3 ±
0.012 m3. The plastic properties of concrete mixes fell within the required ranges based on
CSA and MTO standards, as presented in Table 4.7 with the exception of the L-box test.
Although the L-box ratio was lower than the required limits by CSA or MTO, it was within
the acceptable limit of 0.5 suggested for precast applications by Khayat and Mitchell
(2009) [5]. The increase in cement fineness in HE cement compared to GU cement did not
significantly increase the dosage of HRWR to maintain similar workability. However, the
increase in cement fineness showed a significant increase in the dosage of AEA to maintain
a similar percentage of fresh air content. The addition of LF increased the required dosage
of HRWR and AEA to maintain similar plastic properties to concrete made without LF.
Concrete mixes made with 3µm LF required a higher dosage of HRWR and AEA to
maintain similar workability and fresh air content compared to concrete mixes made with
17µm. The increase in the required HRWR and AEA with HE cement and/or 3µm LF was
due to the increase in surface area, which increases the adsorption of the admixtures and
increases the viscosity of the mix [33].
Table 4.6: Plastic Properties of Concrete Mixes
Mix ID
Plastic Air
Content
(%)
Plastic
Density
(kg/m3)
Slump L-box
(H2/H1)
Column
Segregation
(%) Flow
(mm)
T50
(sec) VSI
J-Ring
(mm)
GU 5.0 2395 680 4 0.5 660 0.67 2.5
GU-17µm 5.5 2431 650 4 0 635 0.58 1.5
GU-3µm 5.2 2439 660 5 0 640 0.50 1.0
HE 5.0 2444 650 5 0.5 638 0.64 1.6
HE-17µm 5.3 2439 680 4 0 660 0.56 1.5
HE-3µm 5.6 2443 650 5 0 630 0.53 0.8
100
Table 4.7: Acceptance Criteria for Plastic Properties of SCC
Test Measure (Unit) Standard Acceptance Limits
Slump Flow Flow Distance (mm) CSA A23.1 (2014) 500-800
J-ring
Difference between
Slump Flow with and
without the J-ring (mm)
MTO SP-SCC (2009) Max. 50mm
CSA A23.1 (2014) Max. 25mm
VSI Visual Assessment MTO SP-SCC (2009) Max. 1.5
L-box Blocking Ratio
MTO SP-SCC (2009) Min. 0.7
CSA A23.1 (2009) Min. 0.8
Khayat and Mitchell
(2009) Min. 0.5
Column Method Static Segregation (%) MTO SP-SCC (2009)
CSA A23.1 (2014) Max. 10%
4.3.6. Hardened Properties of Concrete
Density: Concrete densities are presented in Table 4.8. Each value in the table is the average
of three tests whereas the coefficient of variation was less than 2% (please refer to Section
A.7.3 in Appendix A for the raw data and the statistical analysis). To accurately evaluate
the influence of cement fineness and LF content and fineness, the density was corrected
for 5.0% fresh air content based on Equation 4.5. For example, mix HE-3µm had a fresh
air content of 5.6%. The corrected density, 2470 kg/m3, was greater than the measured
density (2455 kg/m3) based on Equation 4.5.
Corrected density (kg/m3) = Measured Density × [1 +(𝐹𝑟𝑒𝑠ℎ 𝑎𝑖𝑟 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 (%)−5)
100] Eq. 4.5
Corrected density for concrete mix HE-3µm (kg/m3) = 2455 × [1 +(5.6−5)
100] = 2470 kg/m3
Table 4.8: Density of Concrete Mixes
Mix ID
Density (kg/m3) Average
Density
(kg/m3)
Corrected
Average Density
(kg/m3) 12 hrs. 16 hrs. 3 days 7 days 28 days
GU 2356 2346 2351 2360 2375 2358 2358
GU-17µm 2360 2346 2357 2353 2383 2360 2372
GU-3µm 2444 2462 2439 2455 2458 2452 2457
HE 2405 2414 2432 2415 2431 2419 2419
HE-17µm 2421 2415 2430 2442 2440 2430 2437
HE-3µm 2458 2460 2449 2448 2460 2455 2470
101
The following discussion is based on corrected densities. Concrete mix designs made with
HE cement showed higher density compared to counterpart mixes made with GU cement.
The addition of LF increased the density of concrete mixes made with GU and HE cements.
The increase in the density was 1% and 4% for concrete mixes made of GU cement with
17µm and 3µm LF, respectively, compared to 100% GU. Concrete made of HE cement
with 17µm and 3µm LF showed an increase of 1% and 2% in the density, respectively,
compared to the 100% HE. The influence of LF on the density of GU mixes was higher
compared to counterpart mixes made with HE cement. This indicates that the improvement
in particle packing was greater in the coarser cement (i.e., GU cement) when LF was added.
Concrete mixes made of GU and HE cement with 3µm LF showed a 4% and 1% increase
in density, respectively, compared to counterpart mixes made with 17µm. The density
results indicate that the greater difference between LF and cement finenesses, the greater
increase in concrete density.
Compressive strength: The results of the compressive strength are presented in Figure 4.7.
Each compressive strength result is an average of three cylinders and the corresponding
coefficient of variation was less than 4% for all mixes (please refer to Section A.7.3 in
Appendix A for the raw data and the statistical analysis). As might be expected, concrete
mixes made with HE cement showed higher compressive strength at 12 hours to 7 days
compared to GU mixes. At 28 days, the compressive strength of HE and GU mixes was
similar. Concrete mixes made of GU and HE cement with LF showed higher early age (i.e.,
12 and 16 hours) compressive strength compared to counterpart mixes made without LF.
The higher early age compressive strength with HE cement and/or LF can be attributed to
the increase in hydration rate, which was observed in the heat of hydration results and in
agreement with the results obtained from the mortar compressive strength testing. Concrete
made with GU cement and 17µm LF showed similar strength to 100% GU at 3 days. At 7
and 28 days, the compressive strength was lower than 100% GU. Concrete made with GU
cement and 3µm LF showed similar strength to 100% GU at 7 and 28 days. Concrete mixes
made of HE cement and LF showed similar compressive strength to 100% HE at 3, 7 and
28 days regardless of LF fineness. Concrete mixes made of GU and HE cement with 3µm
LF showed higher compressive strength at 12 hours to 7 days compared to counterpart
mixes made with 17µm. At 28 days the compressive strength of GU and HE mixes made
with 3µm and 17µm LF was similar. The effect of LF on the compressive strength was
102
mainly influenced by increasing the hydration rate and the production of calcium
monocarboaluminate, which increase the early age strength (i.e., 12 and 16 hours) and the
dilution effect, which was observed at later age (i.e., 3 to 28 days). Based on the results,
the dilution effect caused by LF could be controlled by increasing the fineness of the
cement or LF.
Figure 4.7: Compressive Strength of Concrete Cylinders
UPV: The UPV was used to assess the density and homogeneity of concrete. The quality
of concrete can be classified as excellent, good and doubtful for the UPV values of 4500
m/s and above, 3500 m/s to 4500 m/s and 3000 m/s to 3500 m/s, respectively [34,35]. The
results of the UPV are presented in Figure 4.8. Each UPV value is an average of three tests
and the corresponding coefficient of variation was less than 3% for all mixes (please refer
to Section A.7.3 in Appendix A for the raw data and the statistical analysis). All concrete
mixes exhibited UPV values between 4500 m/s and 4900 m/s at 16 hours and
approximately 5100 m/s at 28 days. Therefore, all mixes can be classified as excellent
35
40
45
50
55
60
65
70
75
0.1 1 10 100
Co
mp
ress
ive
Str
ength
(M
Pa)
Age (Days) - Log Scale
GU GU-17µm GU-3µm
HE HE-17µm HE-3µm
2873
16 hrs.12 hrs.
103
concrete. Concrete mixes made of HE cement showed higher UPV at 12 hours to 7 days
compared to counterpart mixes made with GU cement. At 28 days, all concrete mixes made
of HE and GU cement had similar UPV, as presented in Figure 4.8. The addition of LF
increased the UPV at 16 hours to 7 days for concrete mix designs made with GU and HE
cement. At 28 days, no effect of LF was observed on the UPV of concrete mixes made of
GU and HE cement. The increase in the UPV with the addition of LF was greater in
concrete mixes made of GU cement compared to concrete mixes made of HE cement.
Concrete mixes made of 3µm LF had higher UPV values compared to counterpart mixes
made of 17µm LF. The UPV results are in agreement with the concrete compressive
strength and density results.
Figure 4.8: UPV Results of Concrete Mixes
Elastic Modulus: The results of the elastic modulus are presented in Table 4.9. Each value
in the table is an average of three tests and the corresponding coefficient of variation was
less than 4% for all mixes (please refer to Section A.7.3 in Appendix A for the raw data
and the statistical analysis). Concrete mix designs made with HE cement showed higher
elastic modulus than counterpart mixes made with GU cement at 12 hours to 7 days, as
shown in Table 4.9. The higher elastic modulus in HE mixes was due to the higher early
4000
4200
4400
4600
4800
5000
5200
5400
0.1 1 10 100
UP
V (
m/s
)
Age (Days) - Log Scale
GU GU-17µm GU-3µm
HE HE-17µm HE-3µm
28 73
16 hrs.12 hrs.
104
age strength compared to GU mixes. At 28 days, all concrete mixes had an elastic modulus
of approximately 41 GPa. Concrete mix designs made with LF showed improved elastic
modulus compared to concrete mixes without LF at 12 hours. At 16 hours to 28 days, the
elastic modulus of concrete mix designs made with and without LF was similar. The elastic
modulus results are in agreement with the concrete compressive strength and UPV results.
As expected, a strong correlation was observed between elastic modulus, UPV and
compressive strength, as presented in Figure 4.9. In this figure, a linear relationship was
observed between the elastic modulus, UPV and the compressive strength with R2 of 0.85.
In Figure 4.9, the scale of the UPV and compressive strength axes were adjusted to align
the two regression lines representing the UPV-elastic modulus relationship and the
compressive strength- elastic modulus relationship.
Table 4.9: Elastic Modulus of Concrete Mixes
Mix ID Elastic Modulus (GPa)
12 hrs. 16 hrs. 3 days 7 days 28 days
GU 26.1 32.6 35.0 37.3 40.7
GU-17µm 27.4 32.8 35.6 37.1 41.0
GU-3µm 31.3 34.8 36.0 38.1 41.0
HE 31.6 35.1 37.1 39.0 41.4
HE-17µm 33.4 35.4 37.2 38.9 40.6
HE-3µm 34.4 36.1 38.4 39.7 41.7
105
Figure 4.9: Relationship between Elastic Modulus, UPV and Compressive Strength
4.3.7. Transport Properties of Concrete
The RCPT values of concrete are presented in Figure 4.10 (please refer to Section A.7.4 in
Appendix A for the raw data and the statistical analysis). Concrete mix designs made of
HE cement with and without LF showed lower (13 to 23%) RCPT values compared to
counterpart mixes made with GU cement. Concrete mix designs made with LF showed
lower RCPT values compared to the corresponding control mix (i.e., 100% GU or 100%
HE). Concrete mix designs made of GU cement with 17µm and 3µm LF showed 28% and
33% decrease in the RCPT values, respectively, compared to 100% GU. HE concrete mixes
made with 17µm and 3µm LF showed a reduction of 18% and 30% in the RCPT values,
respectively, compared to 100% HE. This indicates that LF had a greater influence on the
RCPT values of GU mixes compared to HE mixes. This observation was also noted in the
compressive strength, UPV and density results. Concrete mixes made with 3µm LF showed
lower RCPT values compared to counterpart mixes made with 17µm. The decrease in the
RCPT values with an increase in cement or LF finenesses could be due to two factors.
Firstly, concrete made with finer cement or LF showed improved density, which indicates
lower pore volume and better particle packing compared to counterpart mixes made with
coarser cement or LF. Secondly, the percentage of calcium monocarboaluminate was
R² = 0.85
25
35
45
55
65
75
85
4100
4250
4400
4550
4700
4850
5000
5150
5300
5450
25 30 35 40 45
Co
mp
ress
ive
Str
ength
(M
Pa)
UP
V (
m/s
)
Elastic Modulus (GPa)
UPV Compressive Strength
106
higher in mixes made with finer cement or LF compared to counterpart mixes made with
coarser cement or LF at 28 days.
Figure 4.10: RCPT Values of Concrete Mixes at 28 Days
4.3.8. Durability Performance of Concrete
Linear shrinkage: The results of the linear shrinkage testing are presented in Figure 4.11.
Each curve in the figure is the average of three prisms (please refer to Section A.7.5 in
Appendix A for statistical analysis). Concrete mix designs made with HE cement showed
lower linear shrinkage compared to counterpart mixes made with GU cement. The addition
of LF reduced the linear shrinkage in concrete mix designs made with GU or HE cement.
The reduction in linear shrinkage in the presence of LF was greater in concrete mix designs
made with GU cement compared to HE cement mixes. Linear shrinkage decreased when
the LF size was reduced from 17μm to 3μm.
The increase in cement fineness and the addition of LF decreased the permeability. This
makes the loss of free water (gained during water immersion before the exposure to 50%
RH) in concrete more difficult and thus reduces the linear shrinkage. In addition, concrete
made with LF had less total water content than corresponding control mixes without LF.
0
100
200
300
400
500
600
700
0% Blended LF 15% of 17µm LF 15% of 3µm LF
28
Day
RC
PT
(C
oulo
mb
s)
GU HE Series3
107
This may lead to a higher initial free water content in concrete mixes made without LF.
Nevertheless, since the concrete had a low water-to-cement ratio and was steam cured for
16 hours, it is expected that most of the free water in the mix was consumed in the hydration
reaction. However, no laboratory testing has been conducted to confirm this assumption.
The results of the linear shrinkage are in agreement with the findings in the literature
[36,37].
Figure 4.11: Linear Shrinkage of Concrete Mixes
Figure 4.12 presents the relationship between LF reactivity, RCPT and linear shrinkage
results at 28 days. The figure reveals that the increase in LF reactivity reduces the
permeability and linear shrinkage. This was due to the production of calcium
monocarboaluminate that fills the voids and thus reduces the permeability of concrete.
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0 10 20 30 40 50 60 70 80
Lin
ear
Shri
nkag
e (%
)
Age (Days)
GU GU-17µm GU-3µmHE HE-17µm HE-3µm
108
Figure 4.12: Effect of LF Reactivity on RCPT and Linear Shrinkage of Concrete Mixes at
28 Days
Sulfate resistance: The results of the sulfate expansion are presented in Figure 4.13. Each
curve in the figure is the average of three mortar bars (please refer to Section A.7.5 in
Appendix A for the raw data and statistical analysis). Mortar mix designs made with HE
cement showed lower expansion compared to counterpart mixes made with GU cement.
No influence of LF was observed on the sulfate expansion at the end of the 6-month
exposure period. The expansion of GU and HE mix designs was approximately 0.038%
and 0.031%, respectively, which was less than the moderate sulfate expansion limit (0.1%
after 6 months of exposure) set by ASTM C1012. By comparing the expansion curves in
Figure 4.13, it was observed that the deviation between GU and HE mix designs occurred
in the first week of exposure and thereafter the slope (i.e., the rate of expansion) of GU and
HE mixes was similar. This could be explained by the higher rate of hydration in mix
designs made with HE cement compared to GU, especially at the early age. It is important
to note that all specimens were placed in the sulfate solution at the same cube compressive
strength (20 ± 1 MPa) as required by ASTM C1012. This was achieved by reducing the
accelerated curing time at 35 ºC from 14 hours in GU cement to 13 hours in HE cement.
Although the SO3 content was high in GU and HE cements (4.01% and 4.26%,
respectively), the cement showed lower sulfate expansion than the limit set for moderate
0.010
0.012
0.014
0.016
0.018
0.020
0.022
0.024
0.026
0.028
0.030
100
200
300
400
500
600
700
0.0 0.5 1.0 1.5 2.0
Lin
ear
Shri
nkag
e at
28
Day
s (%
)
RC
PT
at
28
Day
s (
Co
ulo
mb
s)
Reacted LF at 28 Days (wt%)
RCPT Linear Shrinkage
109
sulfate resistance cement. This can be attributed to the presence of SF, which has two main
effects. Firstly, SF decreases the permeability through the production of secondary calcium
silicate hydrate (CSH). Secondly, SF reduces the Ca(OH)2 content, which is consumed in
the pozzolanic reaction. This finding is in agreement with the literature [38,39].
Figure 4.13: Sulfate Expansion (ASTM C1012) of Mortars Made of GU and HE Cements
with/without LF
Freeze-thaw and salt scaling resistance: The freeze-thaw and salt scaling resistance of
concrete are presented in Table 4.10. Each value in the table is the average of two prisms
for the freeze-thaw test or the average of two slabs for the salt scaling test (please refer to
Section A.7.5 in Appendix A for the raw data and statistical analysis). All concrete mix
designs showed high resistance to freeze-thaw cycles (durability factor >98% after 300
cycles). According to Ontario Provincial Standard Specification (OPSS) 1821, the
maximum allowable mass loss due to the salt scaling value is 0.80 kg/m2 [40]. All concrete
mix designs showed a lower salt scaling value compared to OPSS 1821 limit. All mix
designs showed a salt scaling value of approximately 0.2 kg/m2 except for concrete mixes
made with GU cement and LF where the salt scaling was approximately 0.4 kg/m2. The
addition of LF or increase in cement fineness did not impact the freeze-thaw or deicer salt
scaling properties.
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Len
gth
Chan
ge
(%)
Age (weeks)
GU GU-17µm GU-3µm HE HE-17µm HE-3µm
Moderate Sulfate Resistance Expansion Limit (0.1% at 6 Months)
110
Table 4.10: Freeze-Thaw and Salt Scaling Resistance of SCC Mix Designs
Mix ID
Freeze-Thaw Resistance Salt Scaling
Mass Loss
(kg/m2) Length Change (%)
Durability Factor
(%)
GU 0.0110 98.0 0.019
GU-17µm 0.0132 98.1 0.444
GU-3µm 0.0120 97.9 0.376
HE 0.0120 99.0 0.253
HE-17µm 0.0167 97.0 0.198
HE-3µm 0.0167 97.1 0.204
4.4. Statistical Analysis
A multiple linear regression analysis was conducted to identify which independent variable
(cement fineness, LF content and LF size) had a greater influence on the dependent
variables (hardened and transport properties). The analysis was conducted at a confidence
level of 95%, as presented in Table 4.11. For each set of data representing an independent
variable, the data were normalized (i.e., dividing by the highest value). The value of the
beta coefficient for each independent variable was used to identify the influence on the
dependent variable [41]. The highest beta coefficient precedes the most influential
independent variable. Table 4.12 presents the controlling variables influencing mechanical
properties (i.e., compressive strength, UPV and elastic modulus) and transport properties
(i.e., RCPT). From this table, it was observed that cement fineness was the most influential
variable on mechanical and transport properties. It was also observed that LF content and
fineness were the second and third most influential variables on the mechanical and
transport properties of concrete.
111
Table 4.11: Multiple Linear Regression Analysis
Property Prediction Equation R2
Mechanical Properties
Compressive Strength
Early Age
(12 and 16 hours) Concrete Compressive Strength (MPa) =
50.0 × C + 5.3 × LFC − 5.5 × LFS + 31.1 × As − 23.2 0.93
Later Age
(3, 7 and 28 days) Concrete Compressive Strength(MPa) =
14.1 × C + 1.2 × LFC − 3.0 × LFS + 0.4 × Am + 49.1 0.85
UPV
Early Age
(12 and 16 hours) Concrete UPV (m/s) =
1723 × C + 299 × LFC − 125 × LFS + 724 × As + 2375 0.92
Later Age
(3, 7 and 28 days) Concrete UPV (m/s) =
793 × C + 113 × LFC − 112 × LFS + 9 × Am + 4131 0.82
Elastic Modulus
Early Age
(12 and 16 hours) Concrete Elastic Modulus (GPa) =
18.50 × C + 3.20 × LFC − 2.30 × LFS + 15.13 × As +1.40
0.89
Later Age
(3, 7 and 28 days) Concrete Elastic Modulus (GPa) =
7.12 × C + 0.89 × LFC − 0.90 × LFS + 0.16 × Am
+ 29.89
0.90
Transport Property
Early Age
(12 and 16 hours) RCPT (Coulombs) = −490 ∙ C − 177 ∙ LFC + 51 ∙ LFS −165 ∙ As − 70 ∙ Am + 1221
0.97
Where:
C: cement fineness coefficient = 𝐵𝑙𝑎𝑖𝑛𝑒 𝐹𝑖𝑛𝑒𝑛𝑒𝑠𝑠 (
𝑚2
𝑘𝑔)
514 (i.e., for GU = 0.81 and HE
=1.00)
LFC: blended LF content coefficient = 𝐿𝐹 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 (%)
15
LFS: blended LF size coefficient = 𝐿𝐹 𝑠𝑖𝑧𝑒 (µ𝑚)
17
As: steam curing period coefficient = steam curing period (ℎ𝑜𝑢𝑟𝑠)
16
Am: moist curing period coefficient = moist curing period (𝑑𝑎𝑦𝑠)
28
112
Table 4.12: Controlling Variables of Concrete Mixes
Property
Controlling Variables
(1= highest influence , 4= lowest influence)
1 2 3 4
Mechanical Properties
Compressive Strength
Early Age (12 and 16 hours) C AS LFS LFC
Later Age (3, 7 and 28 days) C LFS LFC Am
UPV
Early Age (12 and 16 hours) C AS LFC LFS
Later Age (3, 7 and 28 days) C LFC LFS Am
Elastic Modulus
Early Age (12 and 16 hours) C AS LFC LFS
Later Age (3, 7 and 28 days) C LFS LFC Am
Transport Property
RCPT at 28 Days C LFC/ AS Am LFS
C: Cement type
LFS: LF size
LFC: LF content
Am: Moist curing duration
As: Steam curing duration
4.5. Conclusions
(i) The early age (i.e., 12 and 16 hours) hardened properties (i.e., compressive strength,
ultrasonic pulse velocity, density and elastic modulus) of concrete mix designs were
improved with the addition of limestone filler and increasing cement fineness. No
influence of limestone filler or cement fineness on the hardened properties was
observed at later ages (i.e., 3 to 28 days).
(ii) Limestone filler reduced the chloride permeability and linear shrinkage of concrete.
This reduction was attributed to the increase in concrete density and the production
of calcium monocarboaluminate.
(iii) Concrete made with finer limestone filler (i.e., 3µm) had improved hardened,
transport properties and durability performance compared to concrete made with
coarser limestone filler (i.e., 17µm).
(iv) Concrete mix designs made with limestone filler showed similar durability
performance with respect to sulfate attack, freeze-thaw cycles and salt scaling
compared to control mix designs without limestone filler.
113
(v) Based on statistical analysis, the most influential variable on mechanical and
transport properties was cement fineness followed by limestone filler content and
fineness.
(vi) Based on the findings of this chapter, the use of 15% limestone filler (17µm and
3µm) can enhance the early age hardened properties of SCC compared to the same
mixture without limestone filler. Furthermore, the use of 15% limestone filler
(17µm and 3µm) did not adversely impact the durability performance.
4.6. Acknowledgments
This research was supported by the Ministry of Transportation of Ontario. Opinions
expressed in this thesis are those of the authors and may not necessarily reflect the views
and policies of the Ministry of Transportation of Ontario. The authors would like to
acknowledge Holcim Canada for providing the cement and Omya Canada for providing
the limestone, Euclid Admixture Canada Inc. for providing the chemical admixtures and
Dufferin Aggregates for providing the sand and coarse aggregate.
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Using CEMHYD3D. Cement and Concrete Composites, Vol. 28, No. 2, pp. 124–129.
[22] Kuzel, H., and Baier, H. (1996). Hydration of Calcium Aluminate Cements in the
Presence of Calcium Carbonate. European Journal of Mineralogy, Vol. 8, pp. 129–
141.
[23] Yio, M., Phelan, J., Wong, H., and Buenfeld, N. (2014). Determining the Slag
Fraction, Water/Binder Ratio and Degree of Hydration in Hardened Cement Pastes.
Cement and Concrete Research, Vol. 56, pp. 171–181.
[24] Pane, A., and Hansen, W. (2005). Investigation of Blended Cement Hydration by
Isothermal Calorimetry and Thermal Analysis. Cement and Concrete Research, Vol.
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[25] CSA A23.1/A23.2 (2014). Concrete Materials and Methods of Concrete
Construction/Test Methods and Standard Practices for Concrete. Canadian Standards
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[26] Ministry of Transportation (2014). Ontario Laboratory Testing Manual.
[27] Rahhal, V., Bonavetti, V., Trusilewicz, L., Pedrajas, C., and Talero, R. (2012). Role
of the Filler on Portland Cement Hydration at Early Ages. Construction and Building
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(2012). Influence of Limestone Filler and Viscosity-modifying Admixture on the
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Consolidating Concrete. ACI Materials Journal, Vol. 107, No. 3, pp. 231–238.
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Cements. Cement and Concrete Composites, Vol. 27, pp. 191–196.
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117
Chapter 5 - Delayed Ettringite Formation in Self-Consolidating Concrete Containing Limestone Filler
Abstract
This chapter investigates the influence of limestone filler on the early and later age
hardened properties, transport properties and durability performance of self-consolidating
concrete steam cured at different temperatures. Four types of cement, namely CSA type
GU, HE, GUL and HS were used. Limestone filler with two nominal particle sizes of 17µm
and 3µm were used to replace 15% of cement by weight. All concrete mixes had 5% silica
fume and water-to-cement ratio of 0.34. Concrete specimens were steam cured at a
maximum temperature of 55°C, 70°C and 82°C. All steam curing regimes had a total
duration of 16 hours. The hardened properties of concrete were evaluated using
compressive strength and ultrasonic pulse velocity tests at 16 hours and at 28 and 300 days.
The transport properties were evaluated using rapid chloride permeability test at 28 and
300 days. The durability performance of concrete was assessed by measuring concrete
expansion and concrete resistance to freeze-thaw cycles. The concrete expansion in water
at 23°C was measured for 300 days followed by freeze-thaw testing for 300 cycles. The
results showed that limestone filler increases the 16-hour compressive strength and
ultrasonic pulse velocity when concrete was steam cured at 55°C. Limestone filler did not
have any significant adverse effect on the later age (28 days to 300 days) compressive
strength or ultrasonic pulse velocity regardless of steam curing temperature. The
permeability of concrete at 28 and 300 days was reduced in the presence of limestone filler.
Concrete mixes steam cured at 82°C expanded and developed microcracks after 300 days.
This expansion and cracking caused a significant reduction in the freeze-thaw resistance
compared to concrete mixes steam cured at 55°C.
Keywords: self-consolidating concrete, limestone filler, steam curing, compressive
strength, delayed ettringite formation, freeze-thaw.
118
5.1. Introduction
The precast/prestressed industry in Canada, which started in the 1950’s, has grown
significantly to become a 2 billion dollars’ industry in 2014 [1,2]. The shorter construction
period and the better concrete quality are two of the main advantages of the
precast/prestressed applications compared to cast-in-place applications [3]. In the
precast/prestressed plants, concrete curing is usually carried out in a tent with a limited
space that can accommodate a certain number of elements. The turnaround time including
casting, curing and demolding is typically 24 hours [4,5].
The use of self-consolidating concrete (SCC) in precast/prestressed applications can reduce
the turnaround time [6]. This time saving is a result of reduced required labour, surface
finishing, and noise and congestion at casting location [7]. However, due to the higher
cement content, SCC has a greater cost and negative environmental impact compared to
traditional concrete [8]. The use of a filler material such as limestone filler (LF) as a cement
replacement can reduce the cost and the negative environmental impact of concrete [9,10].
In the precast/prestressed applications, to maintain the production schedule, steam curing
is often applied to achieve the required demolding compressive strength. During steam
curing, the internal temperature of the concrete elements can rise to a temperature that
ranges between 55°C and 85°C [11,12]. The greater the steam curing temperature the
higher the early age strength and thus shorter curing time. However, concrete exposed to
an elevated temperature at early age can be vulnerable to degradation due to delayed
ettringite formation (DEF) [13,14].
DEF cannot occur without three main conditions. These conditions are (i) the exposure to
elevated temperature at early age, (ii) the existence of enough sulfate in the system and (iii)
a supply of moisture [15,16,17]. The increase in the temperature increases the amount of
sulfate ions adsorbed by CSH [15]. The ability of CSH to adsorb the sulfate ions increases
with the increase in pH (mainly linked to the alkali content in the cement) [18,19]. When
the temperature drops down, the sulfate ions are slowly released. In the presence of sulfate
ions and moisture, monosulfate transform to ettringite. Ettringite forming in the paste
causes the paste to expand and crack. This ettringite is defined as DEF [20]. A secondary
ettringite can also form in cracks and air voids. However, this does not cause any damage
since the secondary ettringite recrystallizes in pre-existing cracks [20]. The literature
119
indicates several other factors that could impact the damage due to DEF. The use of some
pozzolanic materials or SCM can reduce the vulnerability to DEF [21,22]. Entrained air
voids have been reported to accommodate some of the secondary ettringite formation,
however, it does not prevent DEF [23,24].
Although the main factors influencing DEF have been well identified in the literature, three
areas related to DEF still require more research. Firstly, the critical maximum temperature
after which DEF is a concern vary over a wide range. Studies have reported 60°C to 65°C
as a safe limit to prevent DEF [15,25,26] while other studies suggested that the temperature
limit should be within the range of 65°C to 75°C [14,27,28]. This wide range of
temperatures reported in the literature is reflected on the temperature limitations set in the
local and international standards. For example, the Canadian Standard Association CSA
A23.4 sets the maximum steam curing temperature in wet conditions to 60°C, while
Precast/prestressed Concrete Institute (PCI) and Portland Cement Association (PCA) set
the limit to 65°C and 71°C, respectively [12]. Furthermore, many of the departments of
transportation in the USA have a limit on the maximum curing temperature that ranges
from 71°C to 85°C [12]. Secondly, the influence of LF on concrete expansion due to DEF
is not clear. LF has been reported to increase the resistance to DEF [29] while other studies
report reduced resistance to DEF [30,31]. Thirdly, there is limited information in the
literature on how the expansion and damage due to DEF impact the freeze-thaw resistance
of concrete. The aim of this chapter is to contribute toward a better understanding of the
above mentioned three areas. This will be achieved by studying the influence of steam
curing temperature and the presence of LF on concrete expansion due to DEF. In addition,
the influence of the expansion due to DEF on the freeze-thaw resistance of concrete is
assessed.
5.2. Experimental Program
5.2.1. Materials
Four types of cement were used, namely CSA type GU, HE, GUL and HS cement. GU,
HE and GUL cements were supplied by Holcim Canada while HS cement was supplied by
Lafarge Canada. The physical and the chemical composition of the cement are presented
in Table 5.1. GU and HS cements have approximately similar Blaine fineness (GU = 392
m2/kg and HS = 401 m2/kg), however, the total sulfate and alkali contents were different
120
(sulfate content: GU = 4.0%, HS = 2.0% and alkali content: GU = 1.02%, HS = 0.60%).
The reason for including HS cement in this thesis is to evaluate the influence of LF on
concrete expansion when cements of different composition are used. The silica fume (SF)
used was an undensified powder supplied by SKW Canada. The physical and the chemical
properties of cement and SF are presented in Table 5.1. Two LF with nominal particle sizes
of 17µm and 3µm were used (corresponding to a Blaine fineness of 475 m2/kg and 1125
m2/kg, respectively). LF was supplied by Omya Canada. The chemical and physical
properties of LF are presented in Table 5.2. The fine aggregate was natural sand with a
specific gravity of 2.72 and a fineness modulus of 2.84. The coarse aggregate was crushed
limestone with a maximum size of 13 mm. The fine and coarse aggregates were supplied
by Dufferin Aggregates. Two admixtures supplied by Euclid Chemical Company Canada
were used, namely high-range water reducer (HRWR) (Plastol 6400) and air-entraining
admixture (AEA) (Airex-L).
Table 5.1: Chemical and Physical Properties of Cement and SF
Chemical Composition and
Physical Properties
Cement SF
GU HS HE GUL
CaCO3 (%) 2.5 0.0 3.5 11.9 ---
SiO2 (%) 19.6 21.6 19.1 18.2 92.1
Al2O3 (%) 5.2 4.0 5.2 5.0 0.3
Fe2O3 (%) 2.3 4.3 2.4 2.3 0.6
CaO (%) 61.8 65.6 61.6 61.0 0.8
MgO (%) 2.4 1.1 2.4 2.2 0.7
SO3 (%) 4.00 2.1 4.3 4.0 0.2
Na2Oeq (%) 1.02 0.60 1.0 0.9 0.9
C3S (%) 44.9 64.0 55.2 61.9 ---
C3A (%) 10.3 3.0 9.8 9.4 ---
C4AF (%) 7.0 13.0 7.1 6.9 ---
C2S (%) 22.3 14.0 13.2 5.4 ---
LOI at 1150 °C (%) 2.61 0.40 2.1 5.8 2.0
Blaine (m2/kg) 417 401 514 490 ---
121
Table 5.2: Chemical and Physical Properties of LF
Chemical and Physical Properties LF Size
17µm 3µm
LOI at 1050°C (%) 42.8 42.4
CaCO3 (%) 95.0 96.0
MgCO3 (%) 2.0 2.0
% Retained on 44μm mesh 15.000 0.003
Blaine (m2/kg) 475 1125
Specific Gravity 2.7 2.7
5.2.2. Mix Design
The details for ten SCC mix designs containing 5% SF and designed to achieve a minimum
compressive strength of 44 MPa in 16 hours are given in Table 5.3. All concrete mixes had
a w/c ratio of 0.34. The total cementing material content was 450 kg/m3. LF was used to
replace 15% of cement by weight. CSA A23.1-14 requires 6 to 9% fresh air content for
concrete with a maximum aggregate size of 10 mm and 5% to 8% for concrete with a
maximum aggregate size of 14 to 20 mm. Since the maximum aggregate size used in this
thesis was 13 mm, the fresh air content in all concrete mixes was set to 5%. The concrete
mixture made with GUL cement (which had 11.9% interground limestone) was used
without any additional blended LF to represent the commercially available GUL in Canada.
Limestone (blended or interground) was not considered as a cementitious material in w/c
ratio calculation. All concrete mixes had a coarse aggregate content of 900 kg/m3. Concrete
mixing was done in a 30-litre drum mixer. Each concrete mix design was prepared in two
batches of 30 litres. SCC mixes were prepared by blending coarse aggregate and sand with
80% of water for 1 minute followed by the addition of cement and the remaining 20% of
water containing AEA and mixing for 3 minutes. Following that, HRWR was added and
the concrete was mixed for an additional 4 minutes.
122
Table 5.3: Weight Proportions of Concrete Mixes
Mix ID Cement SF
Coarse
Agg. Water
LF Sand/Agg.
Ratio
AEA HRWR Size
(μm) kg/m3
kg/m3 ml/100kg
GU 427.5 22.5 950 150.3 --- --- 0.47 37 900
GU-17µm 360 22.5 950 123.0 17 67.5 0.47 120 2300
GU-3µm 360 22.5 950 123.0 3 67.5 0.47 148 2450
HE 427.5 22.5 950 150.3 --- --- 0.47 45 1000
HE-17µm 360 22.5 950 123.0 17 67.5 0.47 195 2350
HE-3µm 360 22.5 950 123.0 3 67.5 0.47 240 2500
GUL 427.5 22.5 950 126.0 --- --- 0.47 190 2400
HS 427.5 22.5 950 150.3 --- --- 0.47 25 500
HS-17µm 360 22.5 950 121.0 17 67.5 0.47 60 1900
HS-3µm 360 22.5 950 121.0 3 67.5 0.47 70 2000
5.2.3. Curing Regime
Concrete was moist cured at 23°C for two hours (preset period) prior to steam curing. The
selection of 2 hours preset period was based on the initial setting time testing on cement
pastes according to ASTM C191 which showed the initial setting time of 77-94 minutes.
The initial setting time of paste is expected to correlate to the initial setting time of concrete
since paste is the active ingredient in concrete causing the setting. Three steam curing
regimes were used, namely Regime 1, 2 and 3, as presented in Figure 5.1. The maximum
curing temperature was 55°C in Regime 1, 70°C in Regime 2 and 82°C in Regime 3. All
regimes had a heating and cooling rate of`16 °C/hour and a total duration of 16 hours. The
temperature of the chamber was controlled to maintain the required internal temperature of
the samples using Type T thermocouples. The relative humidity was controlled by a steam
generator built into the environmental chamber. After steam curing, concrete cylinders
used in the mechanical properties testing were moist cured at 23°C and 100% RH until
testing. Concrete prisms used in concrete expansion testing were immersed in water at
23°C for 300 days. The use of water instead of limewater was to promote the leaching of
alkali [32]. The reason for curing the concrete cylinders in 100% RH instead of water
immersion (as in concrete expansion prisms) was to extend the results obtained from
Chapter 4 in which all concrete cylinders were moist cured at 100% RH. Furthermore, it
has been reported that immersing concrete in water or exposing to 100% RH have similar
effects in promoting the expansion due to DEF [33]
123
Figure 5.1: Steam Curing Regimes
5.2.4. Testing Methods
Fresh Properties:
Unlike the comprehensive testing of fresh properties conducted in Chapter 4, the fresh
properties testing in this chapter was limited to slump flow and Visual Stability Index (VSI)
in accordance with ASTM C1611-14 and fresh air content using a type-B meter in
accordance with ASTM C231-10.
Air Void Analysis of Hardened Concrete:
Three mix designs were selected for air void analysis, mix GU-17µm, HE and HE-17µm.
The concrete specimens used in this test was 100 mm in width × 120 mm in length. The
polished concrete samples were scanned using high-resolution flatbed scanner and the
analysis was conducted using a computer software (ImageJ with air void analysis script)
[34].
Mechanical Properties:
The mechanical properties of concrete were evaluated using compressive strength and UPV
tests at 16 hours and at 28 and 300 days. At each age, three samples were tested for
compressive strength and UPV and the average value was reported. The compressive
strength testing was measured in accordance with CSA A23.2-9C on samples with 200 mm
10
20
30
40
50
60
70
80
90
0 2 4 6 8 10 12 14 16 18
Tem
per
ature
(°C
)
Steam Curing Duration (hour)
Curing Regime Actual Concrete Temperature
Regime 1
10.0 hours at 55°C
Regime 2
8.1 hours at 70°C
Regime 3
6.6 hours at 82°C
95% RH
124
height × 100 mm diameter [35]. The UPV was measured in accordance with ASTM C597-
09.
Transport Properties:
The transport properties were evaluated using RCPT at 28 and 300 days in accordance with
ASTM C1202-10.
Concrete Expansion:
The concrete expansion was measured using concrete prisms with 50 mm width × 50 mm
depth × 285 mm length in accordance with ASTM C 490-11. Following steam curing,
concrete prisms were immersed in water at 23°C. The initial reading was taken
immediately at the end of steam curing and every 14 days thereafter until 300 days.
Scanning Electron Microscopy:
At the end of 300 days of water immersion, the microstructure analysis of concrete mixes
was evaluated using SEM with a backscattered electron detector on fracture surface. In
addition to the fracture surface analysis, thin-section was prepared for microstructure
analysis of concrete. The thin-sections were cut perpendicular to the strong axis of the
concrete prims at approximately 10 to 20 mm from the edge of the prism. Since one prism
from each mix was selected for the microstructure analysis, caution was taken to avoid the
locations where the fracture surface samples were extracted.
Freeze-Thaw Resistance:
After immersion in water for 300 days, the concrete prisms used in the expansion
measurements were tested for freeze-thaw resistance in accordance with ASTM C666-15.
5.3. Results and Discussion
5.3.1. Fresh Properties
The fresh properties of concrete are presented in Table 5.4. All concrete mix designs had a
fresh air content ranging from 4.9% to 5.7%, a slump flow of 660 ± 30 mm and VSI ranging
from 0 to 0.5. The plastic properties of all concrete mixes fell within the required ranges
based on CSA A23.1-14.
125
Table 5.4: Plastic Properties of Concrete
Mix ID Plastic Air Content (%) Slump
Flow (mm) VSI
GU 5.2 690 0.5
GU-17µm 5.3 640 0
GU-3µm 5.0 655 0
HE 5.4 660 0.5
HE-17µm 4.9 645 0
HE-3µm 5.2 650 0
GUL 5.7 695 0.5
HS 4.9 630 0.5
HS-17µm 5.3 685 0
HS-3µm 5.0 645 0
5.3.2. Air Void Analysis of Hardened Concrete
The results of the air void analysis of hardened concrete are presented in Table 5.5. Three
mix designs were selected, mix GU-17µm, HE and HE-17µm. This table shows that the
hardened air content was within ±0.3 of the air content measured in fresh concrete. The
spacing factor ranged from 0.138 mm to 0.177 mm while the air void specific surface
ranged from 28.19 mm-1 to 33.79 mm-1. The spacing factor of the tested concrete was below
the required value of 0.20 mm set by ASTM C-457-12.
Table 5.5: Results of Air Void Analysis of Hardened Concrete
Mix ID Fresh Air
Content (%)
Air Void Analysis of Hardened Concrete
Calculated Air
Content (%)
Specific Surface
(mm-1)
Spacing Factor
(mm)
GU-17µm 5.3 5.0 28.19 0.177
HE 5.4 5.7 33.79 0.138
HE-17µm 4.9 4.8 32.40 0.157
5.3.3. Compressive Strength
The results of the compressive strength are presented in Figures 5.2, 5.3 and 5.4 (please
refer to Section A.7.3 in Appendix A for the raw data and the statistical analysis). In Figures
5.2, 5.3 and 5.4, the minimum value for the compressive strength axis was set to 44 MPa
which is the required 16-hour compressive strength. Figure 5.2 presents the compressive
strength of concrete mixes steam cured at 55°C while Figures 5.3 and 5.4 present the
126
compressive strength of concrete mixes which were steam cured at 70°C and 82°C,
respectively. Each column in the figure is the average of three samples.
As would be expected, concrete mixes made with HE cement achieved greater 16-hour
compressive strength compared to concrete mixes made with GU cement. However, the
greater 16-hour compressive strength in HE cement mixes compared to GU cement mixes
was only observed at a steam curing temperature of 55°C, as presented in Figure 5.2. When
the steam curing temperature increased to 70°C and 82°C, the 16-hour compressive
strength of concrete mixes made with HE and GU cement was similar, as presented in
Figures 5.3 and 5.4. At 28 days, concrete mixes made of HE and GU cement had similar
compressive strength regardless of steam curing temperature. At 300 days, concrete mixes
made with HE cement had 2% to 6% lower compressive strength compared to concrete
mixes made with GU cement regardless of steam curing temperature.
When the fineness of LF was greater than the fineness of the cement, the addition of LF
increased the 16-hour compressive strength of concrete steam cured at 55°C, as presented
in Figure 5.2. For example, concrete mixture made of GU cement and 17µm LF showed
4% increase in the 16-hour compressive strength compared to the control mixture without
LF. When the LF size was reduced from 17µm to 3µm (i.e., Blaine fineness of LF increased
from 475 m2/kg to 1125 m2/kg) the percentage increase in the 16-hour compressive strength
was 15% compared to the control mixture made of GU without LF. On the other hand,
concrete mixture made of HE cement and 17µm LF showed 4% less 16-hour compressive
strength compared to the control mixture made with HE cement without LF. The lower 16-
hour compressive strength in concrete mixture made with 17µm could be due to the lower
fineness of LF (i.e., 475 m2/kg) compared to HE cement (i.e., 514 m2/kg). Reducing LF
size from 17µm to 3µm increased the 16-hour compressive strength by 3% compared to
the control mixture made with HE cement without LF. At 28 days, concrete mixes made
with GU and HE cement with and without LF had similar compressive strength regardless
of steam curing temperature, as presented in Figures 5.2, 5.3 and 5.4. However, at 300
days, concrete mixes made with LF had 3% to 5% less compressive strength compared to
concrete mixes made without LF. The lower strength in concrete mixes made with LF
compared to concrete mixes made without LF was due to the dilution effect.
127
The concrete mixture which was made with GUL cement and steam cured at 55°C had
similar 16-hour compressive strength compared to the concrete mixture made with blended
GU cement with 3µm LF, as presented in Figure 5.2. However, when the steam curing
temperature was increased from 55°C to 70°C and 82°C, the compressive strength of GUL
mixture was 4% less compared to the concrete mixture made with blended GU cement with
3µm LF, as presented in Figures 5.3 and 5.4. At 28 and 300 days, all concrete mixes made
with GUL cement and blended GU cement with LF (17µm and 3µm) had similar
compressive strength. The change in the chemical composition in GU and HS cement did
not cause any significant effect on the compressive strength. The percentage difference in
the compressive strength between concrete mixes made with GU and HS cements was
within ± 5% regardless of age or steam curing temperature.
The results showed that the steam curing temperature has the greatest influence on the
compressive strength evolution. Increasing steam curing temperature caused a significant
increase in the 16-hour compressive strength, as presented in Figure 5.5. In this figure,
logarithmic regression lines are used to present the evolution of compressive strength at
steam curing temperature of 55°C, 70°C and 82°C. The increase in the steam curing
temperature from 55°C to 70°C and 82°C increased the 16-hour compressive strength by
approximately 12% and 25%, respectively. However, the gain in the compressive strength
in concrete mixes that were steam cured at 70°C and 82°C diminished with time. At 28
days, the compressive strength of concrete mixes steam cured at 55°C, 70°C and 82°C were
approximately the same (70 MPa to 74 MPa). At 300 days, concrete mixes steam cured at
70°C and 82°C had approximately 8% lower compressive strength compared to those cured
at 55°C.
128
Figure 5.2: Effect of Mixing Proportion on the Compressive Strength of Concrete Mixes
Cured at 55°C
Figure 5.3: Effect of Mixing Proportion on the Compressive Strength of Concrete Mixes
Cured at 70°C
44
50
56
62
68
74
80
86
92
0.67 28 300
Co
mp
ress
ive
Str
ength
(M
Pa)
Age (Days)
GU GU-17µm GU-3µm HE HE-17µm HE-3µm
GUL HS HS-17µm HS-3µm 1
16 hours
44
50
56
62
68
74
80
86
92
0.67 28 300
Co
mp
ress
ive
Str
ength
(M
Pa)
Age (Days)
GU GU-17µm GU-3µm HE HE-17µm HE-3µm
GUL HS HS-17µm HS-3µm 1
16 hours
129
Figure 5.4: Effect of Mixing Proportion on the Compressive Strength of Concrete Mixes
Cured at 82°C
Figure 5.5: Effect of Steam Curing Temperature on the Evolution of Compressive
Strength
44
50
56
62
68
74
80
86
92
0.67 28 300
Co
mp
ress
ive
Str
ength
(M
Pa)
Age (Days)
GU GU-17µm GU-3µm HE HE-17µm HE-3µm
GUL HS HS-17µm HS-3µm 1
16 hours
45
50
55
60
65
70
75
80
85
90
0.1 1.0 10.0 100.0 1000.0
Co
mp
ress
ive
Str
ength
(M
Pa)
Age (Days)-Log Scale
55°C 70°C 82°C
Log. (55°C) Log. (70°C) Log. (82°C)
Steam Curing Temperature:
16 hrs. 28 300
82°C
70°C
55°C
130
5.3.4. Ultrasonic Pulse Velocity
The uniformity, density and homogeneity of concrete were assessed using UPV test. Based
on the UPV values, the quality of concrete can be classified as excellent, good or doubtful.
Concrete with excellent quality has a UPV value above 4500 m/s while concrete with good
and doubtful quality has a UPV values between 3500 m/s to 4500 m/s and 3000 m/s to
3500 m/s, respectively [36]. The values of the UPV are presented in Table 5.6. Each UPV
value is the average of three tests and the coefficient of variation was below 4% (please
refer to Section A.7.3 in Appendix A for the raw data and the statistical analysis). All
concrete mixes had a UPV equal or greater than 4500 m/s and therefore considered with
excellent quality. At 16 hours, concrete mixes made with HE cement and steam cured at
55°C had 4% to 11% greater UPV compared to similar mixes made with GU cement.
However, this gain in the UPV in concrete mixes made with HE cement diminished with
time. At 28 and 300 days, concrete mixes which were steam cured at 55°C and made with
GU and HE cement had similar UPV values. No significant effect of LF was observed on
the UPV values regardless of the cement type, curing age or steam curing temperature. The
concrete mixture which was made of GUL cement had similar UPV values compared to
concrete mixes made of GU cement blended with LF (17µm and 3µm) at all ages regardless
of steam curing temperature. Concrete mixes steam cured at 70°C and 82°C had greater
UPV values at 16 hours compared to similar concrete mixes steam cured at 55°C. At 28
and 300 days, no effect of steam curing was observed on the UPV values. The change in
the chemical composition of cement in GU and HS cement did not cause any significant
effect on the UPV values. At any given age, the percentage difference in the UPV values
between concrete mixes made of GU and HS cements were within ± 5% regardless of the
presence of LF, curing duration or steam curing temperature.
131
Table 5.6: UPV Values of Concrete Steam Cured at 55°C, 70°C and 82°C
Mix ID Steam Curing
Temperature
Ultrasonic Pulse Velocity
(m/s)
16 hours 28 days 300 days
GU
55°C
4480 5104 5330
GU-17µm 4701 5080 5412
GU-3µm 4720 5180 5475
HE 4920 5130 5290
HE-17µm 4987 5105 5218
HE-3µm 5000 5138 5285
GUL 4693 5050 5320
HS 4734 5019 5395
HS-17µm 4675 5015 5214
HS-3µm 4592 4950 5193
GU
70°C
4639 5038 5330
GU-17µm 4702 5102 5330
GU-3µm 4702 4975 5330
HE 4702 4963 5193
HE-17µm 4680 4975 5156
HE-3µm 4700 4901 5224
GUL 4752 4980 5301
HS 4533 4995 5348
HS-17µm 4489 4987 5324
HS-3µm 4424 4890 5208
GU
82°C
4734 5000 5358
GU-17µm 4802 5064 5401
GU-3µm 4901 5142 5474
HE 4707 5012 5193
HE-17µm 4802 5000 5290
HE-3µm 4792 4987 5239
GUL 4714 5000 5286
HS 4587 4974 5193
HS-17µm 4612 4857 5189
HS-3µm 4662 4872 5235
132
5.3.5. Rapid Chloride Permeability
The RCPT values are presented in Figures 5.6 and 5.7. Figure 5.6 presents the RCPT values
at 28 days while Figure 5.7 presents the RCPT values at 300 days (please refer to Section
A.7.4 in Appendix A for the raw data and the statistical analysis). Each column in the
figures is the average of three sample whereas the confident of variation was less than 8%.
The coefficient of variation of the RCPT values was higher compared to the compressive
strength and the UPV tests. However, the coefficient of variation of the RCPT values were
below the 42% limit set by ASTM C1202.
In general, all concrete mixes showed RCPT values from 300 to 1400 Coulombs at 28
days and from 200 to 1000 Coulombs at 300 days. According to the Ontario Provincial
Standard Specification OPSS 909 (for prestressed concrete) and OPSS999 (for non-
prestressed concrete), the maximum allowable RCPT value for concrete containing SF is
1000 Coulombs at 28 days. From Figure 5.6, all concrete mixes steam cured at 55°C had
RCPT values lower than 1000 Coulombs. For concrete mixes steam cured at 70°C, all
mixes were approximately around the OPSS limit of 1000 Coulombs except for concrete
mixes made of GUL and HS cements. Concrete mixes which were steam cured at 82°C
had RCPT values greater than 1000 Coulombs except for mix GU-3µm.
The RCPT values of concrete mixes made of HE cement and steam cured at 55°C were
12% to 23% less compared to concrete mixes made with GU cement at 28 and 300 days,
respectively. However, when the steam curing temperature increased from 55°C to 70°C
and 82°C, the RCPT values of concrete mixes made of HE and GU cement were similar at
28 and 300 days.
The addition of LF reduced the RCPT values of concrete compared to concrete mixes made
without LF regardless of curing duration or steam curing temperature. Concrete mixes
made with LF of 3µm had lower RCPT compared to concrete mixes made with 17µm LF.
At 28 days, concrete mixture made with GUL cement had greater RCPT value compared
to concrete mixes made of GU cement blended with 17µm and 3µm LF. At 300 days,
concrete mixture made with GUL cement and concrete mixes made of GU cement blended
with LF had approximately the same RCPT values regardless of steam curing temperature.
At 28 days, concrete mixes made of GU and HS cements had similar RCPT values when
steam cured at 55°C. However, concrete mixes made of HS cement had greater RCPT
133
values compared mixes made of GU cement when steam cured at 70°C and 82°C. At 300
days, concrete mixes made of GU and HS cement had similar RCPT values regardless of
the steam curing temperature.
The steam curing temperature was the most influential variable on RCPT values. Increasing
steam curing temperature from 55°C to 70°C increased the RCPT values by approximately
100% compared to concrete mixes steam cured at 55°C. Further increase in the steam
curing temperature from 70°C to 82°C increased the RCPT values by approximately 124%
compared to concrete mixes steam cured at 55°C. The higher RCPT values in concrete
mixes steam cured at 70°C and 82°C was caused by the higher hydration rate compared to
concrete steam cured at 55°C, which increases the non-uniformity of the hydration products
causing higher concrete permeability [37,38].
Figure 5.6: Effect of Steam Curing Temperature on the RCPT Values of Concrete at 28
Days
0
200
400
600
800
1000
1200
1400
1600
55°C 70°C 82°C
RC
PT
(C
oulo
mb
s)
Steam Curing Temperature
GU GU-17µm GU-3µm HE HE-17µm HE-3µm
GUL HS HS-17µm HS-3µm 1
OPSS 909 Limit
134
Figure 5.7: Effect of Steam Curing Temperature on the RCPT Values of Concrete at 300
Days
5.3.6. Concrete Expansion
The final expansions of concrete mixes after immersion in water for 300 days are presented
in Figure 5.8. The expansion curves of all concrete mixes are presented in Section A.7.5.1
in Appendix A. The expansion curves in Section A.7.5.1 in Appendix A showed higher
initial expansion in the first two weeks of water immersion. This is due to the water intake
causing the swelling of the concrete prisms. However, this expansion is an integral part of
the total expansion that concrete can accommodate before cracking. Furthermore, the
precast/prestressed concrete elements are expected to expand due to the water intake if
exposed to wet environment (the wet environment is also a necessity for DEF expansion).
In addition, by analyzing the expansion curves, the increase in the expansion due to the
increase in steam curing temperature was not influenced by the initial swelling due to the
water intake. Therefore, no correction was made on the concrete expansion to account for
the initial swelling due to the water intake. Visual examination of concrete prisms did not
reveal any visible cracking. The expansions were below 0.05% (expansion at which
concrete starts to crack) after 300 days of immersion in water. When the concrete was
steam cured at 55°C, the expansion of all concrete mixes was below 0.021%. However,
0
400
800
1200
1600
55°C 70°C 82°C
RC
PT
(C
oulo
mb
s)
Steam Curing Temperature
GU GU-17µm GU-3µm HE HE-17µm HE-3µm
GUL HS HS-17µm HS-3µm 1
135
when the steam curing temperature increased from 55°C to 70°C and 82°C, the expansion
of concrete mixes made of GU, HE and GUL was significantly increased, as presented in
Figure 5.8.
Figure 5.8: Effect of Steam Curing Temperature on Concrete Expansion after 300 Days
of Water Immersion
Concrete mixes steam cured at 55°C and made with GU and HE cement had similar
expansion (0.01% after 300 days). However, when the steam curing temperature increased
from 55°C to 70°C and 82°C, concrete mixes made with HE cement had lower expansion
compared to concrete mixes made with GU cement. LF did not influence the expansion of
concrete mixes made of GU and HE cement when the concrete was steam cured at 55°C,
as presented in Figures 5.8. However, LF slightly reduced the expansion of concrete mixes
made of GU and HE cement when the concrete was steam cured at 70°C and 82°C. The
reduction in the concrete expansion with 17µm and 3µm LF was similar in concrete mixes
made with LF compared to the control mixes made of GU and HE cement without LF. This
reduction in the concrete expansion when cement was replaced by LF was due to the
0.000
0.010
0.020
0.030
0.040
0.050
Concr
ete
Ex
pan
sion
at
300 D
ays
(%)
82°C 70°C 55°C Series4Steam curing Temperature:
GU HE HS
Mix ID
136
reduction in cement content, which reduces the amount of DEF that could form in the
system and thus reduces the expansion of the concrete. In addition, concrete mixes made
with LF had lower permeability compared to concrete mixes made without LF. The lower
permeability of concrete restricts the mobility of water and thus reduces the expansion. To
prove this, Figure 5.9 present the relationship between concrete expansion and RCPT
values at 300 days. This figure shows a strong correlation between concrete expansion and
RCPT values.
Figure 5.9: Relationship between Concrete Expansion and RCPT Values in Mixes Made
of GU, HE and GUL at 300 Days
The concrete mixture made with GUL cement showed similar expansion compared to
concrete mixes made of GU cement blended with 17µm and 3µm LF at a steam curing
temperature of 55°C. However, when the steam curing temperature increased to 70°C and
82°C, GUL concrete mixture showed lower expansion compared to concrete mixes made
with GU cement blended with LF of 17µm and 3µm. Concrete mixes which were made of
HS cement and steam cured at 55°C had similar expansion compared to mixes made of GU
cement (approximately 0.015%). However, when the steam curing temperature increased
to 70°C and 82°C the expansions of concrete mixes made of HS cement were significantly
less compared to concrete mixes made of GU cement. After 300 days, the expansions of
concrete mixes steam cured at 70°C and 82°C and made of HS cement was below 0.021%
R² = 0.82
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
0.040
0.045
0.050
0 200 400 600 800 1000 1200 1400
Co
ncr
ete
Exp
ansi
on a
fter
30
0 D
ays
RCPT Values at 300 Days (Coulombs)
137
whereas the expansions in concrete mixes made of GU cement was approximately 0.037%
at 70°C and 0.042% at 82°C. The reduction in the concrete expansion when the HS cement
was used was due to the lower sulfate and alkali contents compared to GU cement which
means less produced DEF in HS cement mixes compared to GU cement mixes.
Steam curing temperature had a significant effect on the expansion of concrete made of
GU, HE and GUL cements. The increase in the expansion in concrete mixes steam cured
at 70°C and 82°C was 156% and 166%, respectively, compared to concrete mixes steam
cured at 55°C. It was also observed that a significant increase in concrete expansion occurs
when the steam curing temperature increased from 55°C to 70°C. However, there was no
significant increase in the concrete expansion when the steam curing temperature was
increased from 70°C to 82°C.
Concrete expansion did not cause any loss in the mechanical properties of concrete steam
cured at 70°C and 82°C after 300 days of water immersion. This might be due to the lower
level of expansion (maximum expansion was below 0.045%) observed in the concrete,
which agrees with the observations from other research studies [15,16,39].
The concrete expansion was reduced with the use of HE cement (instead of GU), the use
of LF and the use of GUL cement (instead of blended GU cement with 17µm and 3µm
LF). However, this reduction was insignificant compared to the reduction that could be
achieved by reducing the steam curing temperature or reducing the sulfate and alkali
contents in the cement. The expansion of concrete mixes made of HS cement was
significantly low compared to the expansion of concrete mixes made of GU, HE and GUL
cements when steam cured at 70°C and 82°C. This suggests that the expansion in GU, HE
and GUL cement mixes when steam cured at 70°C and 82°C was due to DEF. However,
this theory will be examined by microstructural analysis using SEM.
5.3.7. Scanning Electron Microscopy
At the end of 300-day immersion in water, a microstructural analysis of concrete mixes
was carried out using SEM with a backscattered electron detector on fracture surface and
thin-sections. The SEM images revealed that concrete mixes which were made of GU, HE
and GUL cements and steam cured at 70°C and 82°C had secondary ettringite and calcium
hydroxide crystals in the air voids. Figures 5.10 and 5.11 present SEM images of fracture
surface of concrete steam cured at 70°C and 82°C, respectively, taken at the edge of the
138
concrete prisms. It was also observed that the air voids closer to the surface were more
filled with secondary ettringite. On the other hand, no traces of secondary ettringite
formation was observed in concrete mixes steam cured at 55°C, as presented in Figure
5.12. Figure 5.12 presents SEM images of concrete mixes steam cured at 55°C. The SEM
microstructural analysis showed no differences between concrete mixes made with and
without LF. Air voids in concrete mixes which were steam cured at 82°C had more
secondary ettringite in air voids compared to concrete mixes steam cured at 70°C.
Figure 5.10: Fracture Surface SEM (Backscattered Electron) Images of Concrete Steam
Cured at 70°C Showing Secondary Ettringite and Calcium Hydroxide (CH) Crystals
Growing in Air Voids (a) GU, (b) HE, (c) GU-3µm and (d) HE-17µm
139
Figure 5.11: Fracture Surface SEM (Backscattered Electron) Images of Concrete Steam
Cured at 82°C Showing Secondary Ettringite and Calcium Hydroxide (CH) Crystals
Forming in Air Voids (a) GU, (b) GU-17µm, (c) GU-3µm, (d) GUL
Concrete mixes made of HS cement showed no secondary ettringite in air voids when
steam cured at 55°C and 70°C. Nevertheless, secondary ettringite formation was observed
in concrete mixes made of HS cement and steam cured at 82°C, as presented in Figure
5.13. However, this secondary ettringite formation in air voids was significantly less
compared to similar concrete mixes made of GU, HE and GUL cements.
140
Figure 5.12: Fracture Surface SEM (Backscattered Electron) Images of Concrete Steam
Cured at 55°C Showing Empty Air Voids (a) GU, (b) GU-3µm, (c) HS-3µm and (d) HE
Figure 5.13: Fracture Surface SEM (Backscattered Electron) Image of Concrete Mixture
HS-3µm-82°C Showing Minor Secondary Ettringite Formation in Air Void
141
The SEM analysis using thin-sections showed that concrete mixes steam cured at 82°C had
microcracks, as shown in Figure 5.14 for mix GU-17µm (please refer to Section A.7.6 in
Appendix A for the locations of the SEM images in the thin-section and for additional SEM
images). Narrow empty gaps were observed partially surrounding or in some cases fully
surrounding the sand particles, as presented in Figure 5.15. Ettringite deposits were found
in the interfacial transition zone, as presented in Figure 5.16. The ettringite deposits in the
interfacial transition zones and the narrow gaps surrounding the sand particles are typical
signs of expansion due to DEF [22,40]. No microcracks were observed in concrete mixes
steam cured at 55°C and 70°C except for mix GU-70°C, as presented in Figure 5.17. In
mix GU-70°C, the microstructural analysis showed some microcracks. However, these
microcracks were smaller and less connected compared to the same mix steam cured at
82°C, as presented in Figure 5.18. In addition, concrete mixes made of HS cement showed
no microcracks when steam cured at 82°C, as presented in Figure 5.19.
To further assess the influence of LF and steam curing temperature, the distribution of the
secondary ettringite formation was evaluated. For this analysis, four concrete mix designs
were selected, namely GU-82°C, GU-3µm-70°C, GU-3µm-82°C and HS-3µm-82°C. At
10 mm from the edge of the concrete prisms, a cross-section was made. In this cross-
sectional area, the air voids smaller or equal to 200µm in diameter were analyzed. The air
voids were categorized into three categories based on the level of secondary ettringite
formation in the air voids. The first category (Category 1) consisted of air voids that had
minor or no secondary ettringite formation. The second category (Category 2) consisted of
air voids with major secondary ettringite formation but the volume of the air voids was not
completely compromised. The third category (Category 3) consisted of air voids that were
completely filled with secondary ettringite formation. Figure 5.20 presents the secondary
ettringite distribution in mix GU-82°C, GU-3µm-70°C, GU-3µm-82°C and HS-3µm-
82°C. From this figure, it can be observed that the secondary ettringite was mainly
concentrated at the corners of the (50 mm × 50 mm) concrete cross-section. By comparing
Figure 5.20 (a) to (b) it was observed that the addition of LF reduced the secondary
ettringite formation in air voids. However, steam curing temperature seems to have a
greater effect on the secondary ettringite distribution. It can be observed from Figure 5.20
(b) and (c) that the secondary ettringite formation was less aggressive in mix GU-3µm-
70°C compared to GU-3µm-82°C. Figure 5.20 (d) showed minor ettringite formation in air
142
voids at the corner of the concrete cross-section. The secondary ettringite distribution
analysis results showed that the steam curing temperature and the chemical composition of
the cement were the most influential variables on the distribution of secondary ettringite.
This agrees with the findings obtained from concrete expansion results and the
microanalysis of the fracture surface.
Figure 5.14: SEM (Backscattered Electron) Images of Concrete Thin-Section Showing
Microcracks and Secondary Ettringite Filling Smaller Air Voids (Mix GU-17µm-82°C)
Microcrack
Air Voids
Filled with
Secondary
Ettringite
0
500
1000
1500
2000
0 2 4 6
Coun
ts
KeV
Ca
Ca
S
Al
O
143
Figure 5.15: SEM (Backscattered Electron) Images of Concrete (GU-17µm-82°C)
Showing Narrow Empty Gaps Surrounding Sand Particles
Figure 5.16: SEM (Backscattered Electron) Images of Concrete (GU-17µm-82°C)
Showing Ettringite Deposits (Circles) Found in the Interfacial Transition Zone
144
Figure 5.17: SEM (Backscattered Electron) Images of Concrete (a) GU-17µm-55°C and
(b) GU-17µm-70°C
145
Figure 5.18: SEM (Backscattered Electron) Images of Concrete Showing Microcracks
(circles) (a) GU-70°C and (b) GU-82°C
(a)
(b)
146
Figure 5.19: SEM (Backscattered Electron) Images of Concrete (Mix HS-17µm-82°C)
The ettringite distribution presented in Figure 5.20 shows that at 10 mm from the edge of
the concrete prisms, the center of the prisms did not have any significant formation of
secondary ettringite in air voids. The availability of moisture close to the surface of
concrete had two roles in increasing the secondary ettringite formation in air voids. Firstly,
the formation of ettringite requires the presence of moisture and therefore, ettringite
formation was greater in areas close to the surface of the concrete. Secondary, the leaching
of alkali will be greater in areas close to the surface of the concrete.
147
Figure 5.20: Secondary Ettringite Distribution in Air Voids in a Cross-section
(50×50mm) of Concrete (a) GU-82°C, (b) GU-3µm -82°C, (c) GU-3µm-70°C and (d)
HS-3µm-82°C
25 20 15 10 -5 5 10 15 20 25
253 3 3 3 3 3 3 3 3 3
203 3 3 2 2 2 3 3 3 3
153 3 3 2 2 2 2 2 3 3
103 3 2 2 2 2 1 2 3 3
53 2 2 2 1 1 2 2 2 3
-53 2 2 2 1 1 1 2 2 3
-103 3 2 2 1 1 2 3 3 3
-153 3 3 2 2 1 2 2 3 3
-203 3 3 2 2 2 2 3 3 3
-253 3 3 3 3 3 3 3 3 3
25 20 15 10 -5 5 10 15 20 25
253 3 3 3 2 3 3 3 3 3
203 3 3 2 2 2 2 3 3 3
153 3 2 1 2 2 2 2 3 3
103 2 2 1 1 1 1 2 2 3
52 2 2 1 1 1 2 2 2 3
-52 2 2 1 1 1 1 2 2 3
-103 2 2 2 1 1 2 2 3 3
-153 3 2 2 2 1 2 2 2 3
-203 3 3 2 2 2 2 3 3 3
-253 3 3 3 3 3 3 3 3 3
25 20 15 10 -5 5 10 15 20 25
252 2 2 1 1 2 1 1 2 2
202 1 1 1 1 1 1 1 1 2
152 1 1 1 1 1 1 1 1 1
101 1 1 1 1 1 1 1 1 1
51 1 1 1 1 1 1 1 1 1
-51 1 1 1 1 1 1 1 1 1
-102 1 1 1 1 1 1 1 1 1
-151 1 1 1 1 1 1 1 1 1
-201 1 1 1 1 1 1 2 1 2
-252 2 1 1 1 1 1 1 2 2
25 20 15 10 -5 5 10 15 20 25
253 3 3 3 2 2 3 3 3 3
203 3 2 2 2 2 2 2 3 3
153 2 2 1 1 2 1 2 2 3
103 2 2 1 1 1 1 2 2 3
52 2 1 1 1 1 2 1 2 2
-52 2 2 1 1 1 1 2 2 2
-103 2 1 1 1 1 2 2 2 3
-153 2 2 2 2 1 2 2 2 3
-203 3 2 2 2 2 2 3 3 3
-253 3 3 3 2 3 3 3 3 3
Distance (mm) D
ista
nce
(m
m)
Category 1: air voids have minor or no secondary ettringite formation
Category 3: air voids are completely filled with secondary ettringite formation
Category 2: air voids have major secondary ettringite formation but the volume of air voids is not
completely compromised
(a) (b)
(c) (d)
148
5.3.8. Freeze-Thaw Resistance
At the end of 300 days, the freeze-thaw testing was carried out on the concrete prisms used
in expansion measurements. The durability factor of concrete mixes after 300 cycles of
freeze-thaw is presented in Figure 5.21 (please refer to Section A.7.5 in Appendix A for
the raw data and the statistical analysis). Concrete mixes steam cured at 55°C had a
durability factor greater than 96% regardless of the cement type or the presence of LF.
However, when the steam curing temperature increased from 55°C to 70°C and 82°C, the
durability factor of concrete mixes made of GU, HE and GUL cements was significantly
reduced.
Figure 5.21: Effect of Steam Curing Temperature on Durability Factor of Concrete
Concrete mixes which were made with HE cement and steam cured at 70°C had 4% to 19%
greater durability factor compared to concrete mixes made with GU cement. When the
steam curing temperature increased to 82°C, all concrete mixes made with HE and GU
cement had similar durability factors. The addition of LF increased the durability factor of
concrete. This increase in the durability factor with the addition of LF was statistically
significant in concrete mixes made of GU and HE cement and steam cured at 82°C. At
steam curing temperature of 70°C, only concrete mixes made of GU cement showed
40
50
60
70
80
90
100
Dura
bil
ity F
acto
r (%
)
55°C 70°C 82°C Series4
CSALimit
Steam curing Temperature:
GU HE HS
Mix ID
149
statistically significant increase in the durability factor with the addition of LF. Concrete
mixes made with 17µm and 3µm LF had similar durability factor regardless of the cement
type or the steam curing temperature. The concrete mixture made of GUL cement had
similar durability factor compared to concrete mixes made of blended GU cement with
17µm and 3µm LF regardless of the steam curing temperature. Concrete mixes made of
HS cement had a durability factor greater than 92% regardless of the steam curing
temperature.
The loss in the durability factor with the use of GU, HE and GUL cements at the higher
steam curing temperature (i.e., 70°C and 82°C) was due to three factors. Firstly, concrete
mixes steam cured at 82°C except mixes made with HS cement had developed microcracks
at the end of the 300 days of water immersion. Secondly, concrete mixes made of GU, HE
and GUL cements and steam cured at 70°C and 82°C were under greater tensile stress due
to the greater expansion compared to similar mixes steam cured at 55°C. This might reduce
the additional stress due to freeze-thaw cycles that these mixes (i.e., GU, HE and GUL
mixes steam cured at 70°C and 82°C) can accommodate before cracking. Thirdly, concrete
mixes made of GU, HE and GUL cements showed secondary ettringite formation in air
voids when steam cured at 70°C and 82°C. The secondary ettringite formation in air voids
may occupy some of the space that accommodates the expansion of water under freezing
condition. Detwiler and Powers (1999) have reported that the filling of air voids with
secondary ettringite formation does not contribute to the damage due to freeze-thaw cycles
[41]. However, in their testing, the concrete prisms were moist cured for 3 days only
followed by air curing for 25 days before exposed to freeze-thaw cycles. It is not expected
that enough secondary ettringite formation will be produced during this short period of
time specially that the concrete will be under continuous freeze-thaw cycles. On the other
hand, in this thesis, the secondary ettringite formation was initially exhausted before the
exposure to freeze-thaw cycles. Figure 5.14 showed that the smaller air voids, which are
critical to freeze-thaw resistance, are more filled with secondary ettringite compared to the
bigger air voids. However, Figure 5.20 showed that the distribution of secondary ettringite
in air voids was not uniform and was mainly at the corner and the edge of the concrete
prisms. This might cause the outer side of concrete to have a greater expansion compared
to the inner core as there is less available space to accommodate water expansion. The
difference in expansion level in the outer and inner sides of the concrete creates stresses
150
which might accelerate the deterioration under freeze-thaw cycles. The freeze-thaw cycles
have been reported to promote DEF expansion due to the greater stability of ettringite
compared to monosulfate at freezing temperatures [42]. However, in these studies, the
freeze-thaw cycles were applied at early age. In this thesis, the freeze-thaw cycles were
applied at the end of 300 days at which the ettringite formation is expected to be exhausted.
According to CSA A3004-E1, the minimum allowable durability factor is 80% [43].
Concrete mixes made of HS cement had a durability factor greater than 92% regardless of
the steam curing temperature or the presence of LF. All concrete mixes made of GU, HE
and GUL cements which were steam cured at 55°C had a durability factor greater than
95%. However, when the steam curing temperature increased from 55°C to 70°C, concrete
mixes made with GU, HE and GUL cements had a durability factor that is equal or slightly
greater than 80% except for mix GU where the durability factor was 68%. When the
concrete was steam cured at 82°C, all concrete mixes made of GU, HE and GUL cements
did not pass the limit of 80% (durability factor ranged from 56% to 73%). The reduction
in the freeze-thaw resistance was greater in concrete mixes that exhibited greater
expansion, as presented in Figure 5.22. Steam curing temperature and sulfate and alkali
contents in cement were the most significant variable influencing the freeze-thaw durability
factor. Increasing the steam curing temperature from 55°C to 70°C to 82°C caused
approximately 18% and 30% loss in the durability factor, respectively, compared to
concrete mixes steam cured at 55°C.
151
Figure 5.22: Relationship between Concrete Expansion and Loss in Freeze-Thaw
Durability Factor of Concrete
The results obtained on the effect of LF on concrete expansion due to DEF was in
agreement with the study made by Kurdowski and Duszak [29]. However, it contradicts
the findings made by Silva et al. [30]. In Silva’s study, concrete mixes made of LF had
greater expansions compared to the concrete made without LF. However, the compressive
strength of concrete mixes made with LF was 25% less compared to concrete made without
LF at 28 and 90 days. The lower compressive strength in concrete made with LF causes
the tensile strength of concrete to be lower compared to concrete without LF and thus crack
sooner. In addition, the modulus of elasticity is expected to be lower with lower
compressive strength, which results in greater expansion under the same stress level
compared to concrete with higher elastic modulus [44].
5.4. Conclusions
Based on the results of this chapter, the following conclusions can be drawn:
(i) Limestone filler can increase the 16-hour compressive strength and ultrasonic pulse
velocity of concrete steam cured at 55°C. However, this increase in the 16-hour
compressive strength and ultrasonic pulse velocity diminished when the steam
curing temperature increased from 55°C to 70°C and 82°C.
R² = 0.88
0
0.01
0.02
0.03
0.04
0.05
0.06
0 10 20 30 40 50
Exp
ansi
on a
fter
30
0 D
ays
Loss in F/T Durability Factor (%)
152
(ii) The permeability of concrete was reduced in the presence of limestone filler at 28
and 300 days regardless of steam curing temperature.
(iii) LF slightly reduced the expansion of concrete. This reduction in the concrete
expansion was caused by the reduction in cement content, which reduced the
amount of DEF that could form in the system and thus reduces the expansion. In
addition, the reduced permeability in concrete mixes made with LF might also be a
contributing factor in reducing the expansion.
(iv) The concrete mixture made with GUL had similar hardened properties and
durability performance compared to concrete mixes made of GU cement blended
with 17µm and 3µm LF.
(v) Concrete mixes made with HS cement showed similar compressive strength and
ultrasonic pulse velocity values compared to concrete mixes made with GU cement.
However, concrete mixes made with HS cement showed significantly less
expansion compared to concrete mixes made of GU cement. This is due to the lower
sulfate and alkali contents in HS cement compared to GU cement, which reduces
the expansion due to DEF.
(vi) Concrete mixes made of HS cement showed no significant loss in the freeze-thaw
durability factor regardless of the steam curing temperature. On the other hand,
concrete mixes made of GU, HE and GUL cements showed a significant loss in
freeze-thaw resistance when steam cured at 70°C and 82°C.
(vii) The expansion in concrete mixes made of GU, HE and GUL cements reduced the
freeze-thaw resistance of concrete. The higher the concrete expansion, the lower
the durability factor. The reduction in freeze-thaw durability factor was due to three
factors. Firstly, the micrographic analysis showed that concrete mixes steam cured
at 82°C had microcracks prior to freeze-thaw testing. Secondly, concrete mixes
steam cured at 70°C exhibited greater 300-day expansions compared to concrete
mixes steam cured at 55°C. The greater expansion of the concrete steam cured at
70°C causes an increase in the internal stresses and thus there might be less room
to accommodate any additional stresses due to the freeze-thaw cycles before
cracking. Thirdly, concrete mixes steam cured at 70°C and 82°C had secondary
ettringite formation in air voids. This secondary ettringite formation may reduce
the available space that accommodates water expansion under freezing conditions.
153
5.5. Acknowledgments
This research was supported by the Ministry of Transportation of Ontario. Opinions
expressed in this thesis are those of the authors and may not necessarily reflect the views
and policies of the Ministry of Transportation of Ontario. The authors would like to
acknowledge Holcim and Lafarge Canada for providing the cement, Omya Canada for
providing the limestone, Euclid Admixture Canada Inc. for providing the admixtures and
Dufferin Aggregates for providing the aggregates.
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157
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158
Chapter 6 - Key Findings, Contributions and Recommendations
6.1. Key Findings and Contributions
Key outcomes based on the research carried out in this thesis are:
1. A new method was developed to decouple the physical and the chemical effects of
limestone filler. This novel approach consisted of using a brucite filler with similar
physical properties to limestone filler and was used to measure the influence of each
effect of limestone filler on the mechanical and transport properties of steam cured
cement paste, mortar and concrete at 16 hours and 28 days.
2. The physical effect of limestone filler increases the compressive strength of mortar and
concrete at 16 hours. This increase was due to the acceleration in hydration rate and the
reduction in porosity of the mortar.
3. The chemical reactivity of limestone filler, leading to the production of calcium
monocarboaluminate, had an important role in enhancing the microstructure,
mechanical and transport properties of cement paste, mortar and concrete at 16 hours
and at 28 days.
4. At 16 hours, it is observed that the dilution effect alone adversely affects the mechanical
properties of concrete containing 15% limestone filler as a cement replacement.
However, this was offset by the combined beneficial influence of the: i) acceleration in
the hydration reactions, ii) modification of particle size distribution and, iii) production
of calcium monocarboaluminate. This resulted in a greater 16-hour compressive
strength of concrete containing 15% limestone filler compared to concrete made
without limestone filler.
5. Concrete containing 15% limestone filler had similar 28-day compressive strength
compared to concrete made without limestone filler because the dilution effect was
compensated for by the production of calcium monocarboaluminate.
6. The initial setting time was reduced with: increasing limestone filler content and
increasing LF fineness. This finding could be utilized to design shorter steam curing
regimes by applying steam curing sooner. This could create time and energy savings
without compromising the early age strength (i.e., at 12 and 16 hours).
159
7. Beyond the fineness of limestone filler, cement fineness was also an important factor
which influenced the chemical reactivity of limestone filler in pastes made without
silica fume, particularly at early ages (i.e., 16 hours). An increase in the cement fineness
increased the fraction of reacted limestone filler because the sulfate depletion point,
which marks the onset reaction of limestone filler, was reached sooner in finer cement
compared to relatively coarser cement. Therefore, to efficiently use limestone filler in
steam cured concrete, both limestone filler fineness and cement fineness should be
considered.
8. Limestone filler increased the 16-hour mechanical properties of concrete steam cured
at 55°C. However, this effect of limestone filler on the mechanical properties at 16
hours was not observed when the steam curing temperature increased from 55°C to
70°C and 82°C.
9. Limestone filler slightly reduced the expansion of concrete immersed in water at 23°C
for 300 days compared to concrete made without limestone filler. This reduction in the
concrete expansion was caused by the reduction in cement content, which reduced the
amount of DEF that could form in the system and thus reduced the expansion. In
addition, the reduced permeability in concrete mixes made with limestone filler might
also be a contributing factor in reducing the expansion.
10. GUL cement concrete containing 12% of interground limestone had similar hardened
properties and durability performance compared to concrete mixes made of GU cement
blended with 15% of 17µm and 3µm limestone filler used as cement replacement.
11. Although, at 300 days, the expansion of all concrete mixes were below 0.05%, the
corresponding freeze-thaw durability factors vary widely and were mainly controlled
by the steam curing temperature and the chemical composition of the cement. For
example, the durability factors for concrete (made with GU, HE, and GUL cements)
steam cured at 55, 70 and 82°C were 96-99%, 79-85%, and 56-73%, respectively. The
durability factors for concrete made with HS cement were above 92% for all steam
curing temperatures.
12. The mechanical and transport properties of concrete mixes made with HS cement and
steam cured at 70°C and 82°C were similar to concrete mixes made with GU, HE and
GUL cements at 300 days. However, the concrete expansion after 300 days of water
immersion and the loss in the freeze-thaw durability factor were significantly lower in
HS cement concrete compared to concrete mixes made of GU, HE and GUL cements.
160
This was due to the lower sulfate and alkali contents in HS cement compared to GU,
HE and GUL cements, which reduces the expansion due to DEF.
13. The expansion due to DEF in concrete mixes made of GU, HE and GUL cements
reduced the freeze-thaw resistance of concrete. The higher the concrete expansion, the
lower the durability factor. The reduction in the freeze-thaw durability factor was due
to three factors. Firstly, despite no visible surface cracking, the micrographic analysis
showed that concrete mixes steam cured at 82°C had microcracks prior to freeze-thaw
testing. Secondly, concrete mixes steam cured at 70°C exhibited greater 300-day
expansions compared to concrete mixes steam cured at 55°C. The greater expansion of
the concrete steam cured at 70°C yields an increase in the internal stresses and thus less
room to accommodate any additional stresses due to the freeze-thaw cycles before
cracking. Thirdly, concrete mixes steam cured at 70°C and 82°C had secondary
ettringite formation in air voids. This secondary ettringite formation may reduce the
available space that accommodates water expansion under freezing conditions resulting
in lower freeze-thaw resistance.
14. Self-consolidating concrete containing 5% silica fume and 15% limestone filler, steam
cured at 55°C, 70°C and 82°C, exhibited similar or superior mechanical and transport
properties and long term durability performance compared to comparable concrete
without limestone filler. The use of 15% limestone filler as cement replacement is a
viable option for the precast/prestressed applications.
6.2. Recommendations
(i) The effect of limestone particle size (i.e., 3µm compared to 17µm) on the
mechanical properties of steam cured concrete was significant at 12 and 16 hours.
It is recommended to investigate a wider range of limestone particle size which are
available in the Canadian market (for example, 0.7µm, 1µm, 30µm and 10µm).
(ii) Replacing 15% of the cement by 17µm and 3µm limestone filler had no negative
impact on the hardened properties and durability performance at 28 and 300 days.
It is recommended to investigate the effect of higher limestone filler content (for
example, 20% to 30%), which will assist in identifying the limestone filler content
at which limestone filler starts to cause a significant impact on the hardened
properties and durability performance of steam cured concrete.
161
(iii) Based on the results of this thesis, for steam cured concrete containing 5% silica
fume, limiting the steam curing temperature to 70°C was critical to limit the damage
caused by concrete expansion due to DEF. In the case where the steam curing
temperature can rise to a temperature greater than 70°C, it is recommended to use
a cement with low sulfate and alkali contents such as HS cement.
162
Appendix A - Testing Data
This appendix presents the material properties and the raw data for the compressive
strength, UPV, RCPT and concrete expansion measurements. Additional SEM images are
also presented in this appendix.
A.1. Particle Size Distribution of Sand and Aggregate
In this section, the particle size distribution of sand and coarse aggregate is presented and
compared to the upper and lower limits set by ASTM C33, as presented in Figures A.1 and
A.2.
Figure A.1: Particle Size Distribution of Sand
0
10
20
30
40
50
60
70
80
90
100
0.01 0.1 1 10 100
Per
centa
ge
Pas
sing (
%)
Sieve Size (mm)
ASTM C33-Limits Sand Grading
163
Figure A.2: Particle Size Distribution of Coarse Aggregate
A.2. Materials Properties
This section presents the fineness modulus of sand, specific gravity and absorption of sand
and coarse aggregate, as presented in Table A.1. In addition, the density of the raw
materials used in this thesis is presented in Table A.2.
Table A.1: Properties of Sand and Coarse Aggregate
Properties Sand Coarse Aggregate
Fineness Modulus 2.84 ---
Specific Gravity 2.72 2.70
Absorption (%) 0.61 1.75
0
10
20
30
40
50
60
70
80
90
100
1 10 100
Per
centa
ge
Pas
sing (
%)
Sieve Size (mm)
ASTM C33-Limits Coarse Aggregate Grading
164
Table A.2: Density of Raw Materials
Material Density (kg/m3)
Cement 3120
LF 2700
SF 2250
BR 2445
Coarse Aggregate 2700
Sand 2720
HRWR 1190
AEA 1007
A.3. Mixing and Batching of Concrete
Due to the low water-to-cement ratio in concrete, the available 60-litre pan mixer did not
produce a uniform concrete mix when used. Therefore, the concrete was produced in two
30-litre batches using a drum mixer. To evaluate the repeatability of batching, initial trials
was conducted and the fresh properties and compressive strength were evaluated for each
batch. The fresh properties were evaluated using fresh air content, fresh density and slump
flow tests. Tables A.3 and A.4 present a comparison of fresh properties and compressive
strength between trail batches for mixes GU, GU-17µm and GU-3µm. In addition, the fresh
air content was compared in the concrete mix designs which were repeated in Chapters 4
and 5, as presented in Table A.5. The results of Tables A.3, A.4 and A.5 shows a good
repeatability of the concrete batching process.
Table A.3: Comparison of Fresh Properties of Concrete Batches
Mix ID
Fresh Air Content (%) Slump Flow (mm) Density (kg/m3)
Batch
1
Batch
2
Difference
(%)
Batch
1
Batch
2
Difference
(%)
Batch
1
Batch
2
Difference
(%)
GU 5.0 4.9 2.0 670 690 2.9 2385 2405 0.8
GU-17µm 5.6 5.2 7.4 635 665 4.6 2447 2415 1.3
GU-3µm 5.1 5.0 2.0 660 660 0.0 2428 2450 0.9
165
Table A.4: Comparison of Compressive Strength (average of three tests) of Concrete
Batches
Mix ID
16-Hour Compressive Strength (MPa) 28-Day Compressive Strength (MPa)
Batch 1 Batch 2 Difference
(%) Batch 1 Batch 2
Difference
(%)
GU 47.2 48.4 2.5 70.9 74.1 4.4
GU-17µm 49.7 50.3 1.2 68.1 70.3 3.2
GU-3µm 54.8 56 2.2 72.4 74.2 2.5
Table A.5: Comparison of Fresh Air Content in Concrete Mixes Repeated in Chapters 4
and 5
Mix ID Fresh Air Content (%)
Chapter 4 Chapter 5 Difference (%)
GU 5.0 5.2 3.9
GU-17µm 5.4 5.3 1.9
GU-3µm 5.1 5.0 2.0
HE 5.0 5.4 7.7
HE-17µm 5.2 4.9 5.9
HE-3µm 5.4 5.2 3.8
166
A.4. Mortar and Concrete Mix Designs
This section presents the mortar and concrete mix designs used in this thesis. Tables A.6
and A.7 present the mortar and concrete mix designs used in Chapter 2, respectively. Table
A.8 presents the mortar mix designs used in Chapter 3. Table A.9 presents the concrete
mix designs used in Chapter 4 and 5.
Table A.6: Mortar Mix Designs (5 kg Batch)
Mix ID
Weight (g)
Cement LF BF Fine Agg. Water
C 1497.0 0.0 0.0 2994.0 509.0
LF 1272.5 224.6 0.0 2994.0 432.6
BF 1272.5 0.0 224.6 2994.0 432.6
Table A.7: Concrete Mix Designs (30-Litre Batch)
Mix ID Cement LF BF
Coarse
Agg.
Fine
Agg. Water HRWR
kg ml
C 13.5 0.0 0.0 27.0 27.6 4.6 40.5
LF 11.5 2.0 0.0 27.0 28.7 3.9 162.0
BF 11.5 0.0 2.0 27.0 28.4 3.9 162.0
A.3.2. Mortar Mix Designs used in Chapter 3
167
Table A.8: Mortar Mix Designs (5 kg Batch)
Mix ID
Mixing Weight (g)
Cement LF Fine Aggregate Water
GU 1483.7 0.0 2967.4 549.0
GU-5-17µm 1409.5 74.2 2967.4 521.5
GU-10-17µm 1335.3 148.4 2967.4 494.1
GU-15-17µm 1261.1 222.6 2967.4 466.6
GU -5-12µm 1409.5 74.2 2967.4 521.5
GU-10-12µm 1335.3 148.4 2967.4 494.1
GU-15-12µm 1261.1 222.6 2967.4 466.6
GU-5-3µm 1409.5 74.2 2967.4 521.5
GU-10-3µm 1335.3 148.4 2967.4 494.1
GU-15-3µm 1261.1 222.6 2967.4 466.6
HE 1483.7 0.0 2967.4 549.0
HE-5-17µm 1409.5 74.2 2967.4 521.5
HE-10-17µm 1335.3 148.4 2967.4 494.1
HE-15-17µm 1261.1 222.6 2967.4 466.6
HE-5-12µm 1409.5 74.2 2967.4 521.5
HE-10-12µm 1335.3 148.4 2967.4 494.1
HE-15-12µm 1261.1 222.6 2967.4 466.6
HE-5-3µm 1409.5 74.2 2967.4 521.5
HE-10-3µm 1335.3 148.4 2967.4 494.1
HE-15-3µm 1261.1 222.6 2967.4 466.6
168
Table A.9: Concrete Mix Designs (30-Litre Batch)
Mix ID Cement SF
Coarse
Agg.
Fine
Agg. Water
LF
AEA HRWR Size
(μm) kg
kg ml
GU 12.8 0.7 28.5 25.3 4.5 --- 0.0 5.0 121.5
GU-17µm 10.8 0.7 28.5 25.3 3.7 17 2.0 16.2 310.5
GU-3µm 10.8 0.7 28.5 25.3 3.7 3 2.0 20.0 330.8
HE 12.8 0.7 28.5 25.3 4.5 --- 0.0 6.1 135.0
HE-17µm 10.8 0.7 28.5 25.3 3.7 17 2.0 26.3 317.3
HE-3µm 10.8 0.7 28.5 25.3 3.7 3 2.0 32.4 337.5
GUL 12.8 0.7 28.5 25.3 3.8 --- 0.0 25.7 324.0
HS 12.8 0.7 28.5 25.3 4.5 --- 0.0 3.4 67.5
HS-17µm 10.8 0.7 28.5 25.3 3.6 17 2.0 8.1 256.5
HS-3µm 10.8 0.7 28.5 25.3 3.6 3 2.0 9.5 270.0
169
A.5. Chapter 2 Results
Table A.10: Raw Data of Laboratory Testing Carried out in Chapter 2
Mix Sample
#
Total
Porosity
(%)
Cube
Compressive
Strength of
Mortar
(MPa)
Concrete
Compressive
Strength
(MPa)
RCPT - Paste
(Coulombs)
RCPT -
Mortar
(Coulombs)
RCPT -
Concrete
(Coulombs)
Initial
Sorptivity -
Paste
(×10-4
mm/sec0.5)
Initial
Sorptivity
- Mortar
(×10-4
mm/sec0.5)
Initial
Sorptivity -
Concrete
(×10-4
mm/sec0.5)
16 H 28 D 16 H 28 D 16 H 28 D 16 H 28 D 16 H 28 D 16 H 28 D 16 H 28 D 16 H 28 D 16 H 28 D
C
1 9.4 5.9 66.4 91.0 59.1 83.2 11780 9234 4657 3123 2845 1193 25.1 14.9 16.0 14.2 11.1 10.1
2 9.0 5.9 67.9 93.0 61.7 85.4 11256 8765 4978 2978 2687 1217 24.7 15.8 16.7 15.0 11.9 10.3
3 9.6 6.3 67.5 92.0 59.2 86.4 10978 8551 5206 2914 2988 1268 26.9 15.3 15.9 15.2 12.4 9.9
Avg. 9.3 6.0 67.3 92.0 60.0 85.0 11338 8850 4947 3005 2840 1226 25.6 15.3 16.2 14.8 11.8 10.1
SD 0.3 0.2 0.8 1.0 1.5 1.6 407 349 276 107 151 38 1.2 0.5 0.4 0.5 0.7 0.2
COV (%) 3.3 3.8 1.2 1.1 2.5 1.9 3.6 3.9 5.6 3.6 5.3 3.1 4.5 2.9 2.7 3.6 5.6 2.0
LF
1 8.1 6.1 74.0 96.0 64.1 83.7 10903 7543 4317 2545 2380 949 24.5 13.5 15.5 12.9 11.4 8.9
2 7.8 6.4 72.5 94.0 66.8 82.6 10045 7856 4678 2272 2567 838 23.9 14.1 15.1 12.5 11.1 8.5
3 7.8 6.1 70.9 93.2 64.1 85.7 9499 7950 4745 2353 2553 859 25.1 14.4 15.0 13.6 11.1 8.7
Avg. 7.9 6.2 72.5 94.4 65.0 84.0 10149 7783 4580 2390 2500 882 24.5 14.0 15.2 13.0 11.2 8.7
SD 0.2 0.2 1.6 1.4 1.6 1.6 708 213 230 140 104 59 0.6 0.5 0.3 0.6 0.2 0.2
COV (%) 2.2 2.8 2.1 1.5 2.4 1.9 7.0 2.7 5.0 5.9 4.2 6.7 2.4 3.3 1.7 4.3 1.5 2.3
BF
1 8.5 5.9 70.0 88.6 61.1 83.3 10956 8122 4657 2434 2898 997 25.5 14.8 16.0 14.1 12.1 9.1
2 8.9 5.6 71.0 91.9 63.1 81.9 10045 8512 4798 2657 2676 1123 25.1 15.3 16.2 14.4 11.4 9.7
3 8.7 6.0 67.5 89.5 64.8 79.3 10898 8530 4945 2904 2706 1033 24.7 14.9 15.8 13.5 11.9 9.7
Avg. 8.7 5.8 69.5 90.0 63.0 81.5 10633 8388 4800 2665 2760 1051 25.1 15.0 16.0 14.0 11.8 9.5
SD 0.2 0.2 1.8 1.7 1.9 2.0 510 231 144 235 120 65 0.4 0.3 0.2 0.5 0.4 0.3
COV (%) 2.3 3.6 2.6 1.9 2.9 2.5 4.8 2.7 3.0 8.8 4.4 6.2 1.6 1.8 1.3 3.3 3.1 3.6
16 H: 16 hours, 28 D: 28 days
170
A.6 Chapter 3 Results
Table A.11: Hydration Peak of Cement Pastes
Mix Hydration Peak (mW/g) Avg.
(mW/g) SD
(mW/g)
COV
(%) 1 2 3
GU 3.82 3.87 3.82 3.84 0.03 0.8
G-5-17 4.02 3.99 3.96 3.99 0.03 0.8
G-10-17 4.00 4.03 4.03 4.02 0.02 0.4
G-15-17 4.09 4.10 4.07 4.09 0.02 0.4
G-5-12 3.91 3.94 3.97 3.94 0.03 0.8
G-10-12 4.00 4.02 4.04 4.02 0.02 0.5
G-15-12 4.10 4.11 4.05 4.09 0.03 0.8
G-5-3 4.02 3.90 3.97 3.96 0.06 1.5
G-10-3 4.15 4.19 4.12 4.15 0.04 0.8
G-15-3 4.34 4.36 4.35 4.35 0.01 0.2
HE 5.27 5.15 4.99 5.14 0.14 2.7
H-5-17 5.20 5.30 5.40 5.30 0.10 1.9
H-10-17 5.41 5.49 5.48 5.46 0.04 0.8
H-15-17 5.81 5.77 5.82 5.80 0.03 0.5
H-5-12 5.44 5.46 5.48 5.46 0.02 0.4
H-10-12 5.69 5.74 5.86 5.76 0.09 1.5
H-15-12 5.99 6.01 6.02 6.01 0.02 0.3
H-5-3 5.74 5.83 5.85 5.81 0.06 1.0
H-10-3 5.72 5.58 5.71 5.67 0.08 1.4
H-15-3 6.09 6.04 6.07 6.07 0.03 0.4
171
Table A.12: Total Heat Released of Cement Pastes after 20 Hours of Hydration
Mix
Total Heat Released after 20 Hours of
Hydration (J/g)
Avg.
(mW/g) SD
(mW/g)
COV
(%) 1 2 3
GU 161.3 159.5 161.0 160.6 1.0 0.6
G-5-17 168.4 170.4 167.7 168.8 1.4 0.8
G-10-17 172.3 170.4 170.7 171.1 1.0 0.6
G-15-17 173.1 173.7 174.9 173.9 0.9 0.5
G-5-12 168.4 169.3 164.2 167.3 2.7 1.6
G-10-12 171.4 172.3 170.1 171.3 1.1 0.6
G-15-12 173.4 173.9 175.8 174.4 1.2 0.7
G-5-3 170.2 173.2 172.9 172.1 1.7 1.0
G-10-3 174.9 177.4 178.6 177.0 1.9 1.1
G-15-3 186.9 187.7 185.1 186.6 1.3 0.7
HE 184.7 183.5 179.6 182.6 2.7 1.5
H-5-17 190.3 189.4 188.1 189.3 1.1 0.6
H-10-17 195.4 195.2 192.1 194.2 1.8 0.9
H-15-17 200.5 201.5 200.9 201.0 0.5 0.3
H-5-12 194.5 193.2 190.5 192.7 2.0 1.1
H-10-12 199.5 197.4 198.8 198.6 1.1 0.5
H-15-12 202.5 201.5 201.7 201.9 0.5 0.3
H-5-3 197.9 197.1 195.1 196.7 1.4 0.7
H-10-3 199.2 198.2 194.1 197.2 2.7 1.4
H-15-3 204.5 204.1 201.4 203.3 1.7 0.8
172
Table A.13: Ca(OH)2 Content in Cement Pastes at 16 Hours and 28 Days
Mix
Ca(OH)2 Content (wt%)
16 Hours 28 Days
1 2 3 Avg. SD COV(%) 1 2 3 Avg. SD COV(%)
GU 11.8 12.1 11.8 11.9 0.2 1.5 13.9 13.8 13.8 13.8 0.1 0.5
G-5-17 12.5 12.2 12.4 12.4 0.2 1.3 14.3 14.0 14.0 14.1 0.2 1.2
G-10-17 13.0 12.6 12.5 12.7 0.3 2.2 13.7 13.9 14.2 13.9 0.2 1.7
G-15-17 12.8 12.5 12.7 12.7 0.2 1.2 13.1 13.5 13.5 13.4 0.2 1.7
G-5-12 12.1 12.4 12.1 12.2 0.2 1.4 14.2 14.0 13.9 14.0 0.2 1.2
G-10-12 12.6 12.5 12.3 12.5 0.2 1.3 13.9 13.8 13.7 13.8 0.1 0.9
G-15-12 12.4 12.7 12.3 12.5 0.2 1.7 13.7 13.8 13.6 13.7 0.1 0.9
G-5-3 12.8 12.3 12.4 12.5 0.3 2.1 14.1 14.0 14.2 14.1 0.1 0.8
G-10-3 12.6 12.6 13.1 12.8 0.3 2.4 14.2 14.2 13.8 14.1 0.3 1.8
G-15-3 12.5 12.6 12.7 12.6 0.1 0.9 13.9 13.8 13.6 13.8 0.1 0.9
HE 12.1 12.1 12.5 12.2 0.2 2.0 14.0 14.0 14.2 14.1 0.1 0.7
H-5-17 12.7 12.5 12.2 12.5 0.3 2.0 14.0 14.4 14.3 14.2 0.2 1.4
H-10-17 12.9 12.5 12.8 12.7 0.2 1.6 14.8 14.6 14.3 14.6 0.2 1.6
H-15-17 12.7 12.9 12.5 12.7 0.2 1.7 14.6 14.4 14.8 14.6 0.2 1.5
H-5-12 12.8 12.5 13.0 12.8 0.3 2.0 14.4 14.4 14.5 14.4 0.1 0.4
H-10-12 12.9 12.5 12.5 12.6 0.2 1.8 14.7 14.6 14.9 14.7 0.1 0.9
H-15-12 12.5 12.6 13.0 12.7 0.2 2.0 14.6 14.7 15.0 14.8 0.2 1.2
H-5-3 12.7 12.9 13.0 12.9 0.1 1.1 14.6 14.6 15.0 14.7 0.2 1.7
H-10-3 12.7 12.7 12.8 12.7 0.0 0.3 14.7 14.7 14.8 14.7 0.0 0.2
H-15-3 12.5 12.4 12.7 12.5 0.2 1.4 14.4 14.5 14.6 14.5 0.1 0.9
173
Table A.14: LF Reactivity in Cement Pastes at 16 Hours and 28 Days
Mix
LF Reactivity (wt%)
16 Hours 28 Days
1 2 3 Avg. SD 1 2 3 Avg. SD
GU 0.00 0.00 0.00 0.00 0.00 0.15 0.14 0.13 0.14 0.01
G-5-17 0.02 0.01 0.00 0.01 0.01 0.42 0.40 0.38 0.40 0.02
G-10-17 0.07 0.05 0.09 0.07 0.02 1.30 1.22 1.05 1.19 0.12
G-15-17 0.10 0.09 0.08 0.09 0.01 1.57 1.60 1.51 1.56 0.05
G-5-12 0.02 0.01 0.00 0.01 0.01 0.25 0.25 0.28 0.26 0.02
G-10-12 0.11 0.10 0.09 0.10 0.01 1.40 1.20 1.24 1.28 0.10
G-15-12 0.16 0.14 0.12 0.14 0.02 1.29 1.15 1.10 1.18 0.09
G-5-3 0.03 0.02 0.04 0.03 0.01 0.33 0.30 0.30 0.31 0.02
G-10-3 0.18 0.17 0.16 0.17 0.01 1.96 1.96 1.90 1.94 0.03
G-15-3 0.49 0.46 0.49 0.48 0.02 2.30 2.26 2.25 2.27 0.03
HE 0.06 0.05 0.04 0.05 0.01 1.05 0.93 0.90 0.96 0.08
H-5-17 0.10 0.11 0.06 0.09 0.03 1.47 1.47 1.41 1.45 0.03
H-10-17 0.33 0.32 0.28 0.31 0.03 1.12 1.14 1.10 1.12 0.02
H-15-17 0.14 0.11 0.11 0.12 0.02 1.22 1.12 1.02 1.12 0.10
H-5-12 0.37 0.34 0.31 0.34 0.03 1.54 1.55 1.47 1.52 0.04
H-10-12 0.76 0.74 0.72 0.74 0.02 1.38 1.36 1.40 1.38 0.02
H-15-12 0.62 0.59 0.59 0.60 0.02 1.79 1.65 1.48 1.64 0.15
H-5-3 0.67 0.66 0.62 0.65 0.03 1.44 1.44 1.41 1.43 0.02
H-10-3 0.97 0.93 0.92 0.94 0.03 1.62 1.62 1.56 1.60 0.03
H-15-3 1.37 1.35 1.33 1.35 0.02 2.21 2.05 1.83 2.03 0.19
174
Table A.15: The Degree of Hydration of Cement Pastes at 16 Hours and 28 Days
Mix
Degree of Hydration
16 Hours 28 Days
1 2 3 Avg. SD COV(%) 1 2 3 Avg. SD COV(%)
GU 0.61 0.62 0.62 0.62 0.01 0.9 0.81 0.82 0.82 0.82 0.01 0.6
G-5-17 0.66 0.66 0.64 0.65 0.01 2.1 0.85 0.84 0.84 0.84 0.01 0.7
G-10-17 0.68 0.66 0.65 0.66 0.02 2.6 0.85 0.86 0.84 0.85 0.01 1.2
G-15-17 0.66 0.66 0.66 0.66 0.00 0.1 0.83 0.84 0.85 0.84 0.01 1.2
G-5-12 0.67 0.65 0.65 0.66 0.01 1.6 0.85 0.84 0.85 0.85 0.01 0.6
G-10-12 0.67 0.67 0.65 0.66 0.01 1.7 0.84 0.83 0.88 0.85 0.03 3.0
G-15-12 0.66 0.66 0.64 0.65 0.01 1.9 0.84 0.84 0.83 0.84 0.01 0.9
G-5-3 0.66 0.65 0.63 0.65 0.01 2.3 0.85 0.86 0.83 0.85 0.02 2.1
G-10-3 0.66 0.65 0.67 0.66 0.01 1.2 0.85 0.85 0.86 0.85 0.00 0.6
G-15-3 0.68 0.66 0.66 0.67 0.01 1.8 0.84 0.84 0.86 0.85 0.01 1.4
HE 0.64 0.64 0.62 0.63 0.01 2.0 0.82 0.81 0.84 0.82 0.02 2.1
H-5-17 0.66 0.67 0.66 0.66 0.01 1.2 0.83 0.82 0.83 0.83 0.01 0.9
H-10-17 0.67 0.67 0.64 0.66 0.02 2.4 0.82 0.82 0.86 0.83 0.02 2.5
H-15-17 0.65 0.67 0.65 0.66 0.01 1.7 0.82 0.83 0.84 0.83 0.01 1.5
H-5-12 0.67 0.68 0.66 0.67 0.01 1.7 0.84 0.85 0.83 0.84 0.01 1.5
H-10-12 0.68 0.67 0.65 0.67 0.01 2.2 0.84 0.84 0.85 0.84 0.01 0.9
H-15-12 0.68 0.68 0.64 0.67 0.02 3.7 0.84 0.84 0.84 0.84 0.00 0.3
H-5-3 0.67 0.67 0.66 0.67 0.01 1.0 0.86 0.86 0.85 0.86 0.00 0.4
H-10-3 0.67 0.67 0.66 0.67 0.01 1.0 0.87 0.87 0.85 0.86 0.01 1.4
H-15-3 0.66 0.67 0.69 0.67 0.02 2.4 0.85 0.84 0.86 0.85 0.01 1.2
175
Table A.16: Compressive Strength of Mortar Cubes at 12 and 16 Hours
Mix
Degree of Hydration
12 Hours 16 Hours
1 2 3 Avg. SD COV(%) 1 2 3 Avg. SD COV(%)
GU 34.0 34.4 34.8 34.4 0.4 1.2 38.2 37.6 38.8 38.2 0.6 1.6
G-5-17 36.8 36.0 37.0 36.6 0.5 1.4 41.6 40.8 42.0 41.5 0.6 1.5
G-10-17 35.2 36.0 35.6 35.6 0.4 1.1 38.0 37.2 39.2 38.1 1.0 2.6
G-15-17 36.1 35.6 35.2 35.6 0.5 1.3 36.4 38.8 36.8 37.3 1.3 3.4
G-5-12 34.4 35.2 33.6 34.4 0.8 2.3 39.2 39.6 38.8 39.2 0.4 1.0
G-10-12 34.4 34.0 34.8 34.4 0.4 1.2 41.2 41.6 42.4 41.7 0.6 1.5
G-15-12 34.4 35.2 33.6 34.4 0.8 2.3 37.0 37.0 37.0 37.0 0.0 0.0
G-5-3 34.8 34.4 35.2 34.8 0.4 1.1 38.4 37.6 37.0 37.7 0.7 1.9
G-10-3 35.2 36.0 35.2 35.5 0.5 1.3 38.4 38.8 39.6 38.9 0.6 1.6
G-15-3 35.6 36.0 36.4 36.0 0.4 1.1 36.8 37.6 38.4 37.6 0.8 2.1
HE 40.4 40.4 40.4 40.4 0.0 0.0 46.0 45.0 46.0 45.7 0.6 1.3
H-5-17 42.8 42.8 41.6 42.4 0.7 1.6 46.4 47.6 47.2 47.1 0.6 1.3
H-10-17 42.8 43.6 44.0 43.5 0.6 1.4 48.0 48.0 47.8 47.9 0.1 0.2
H-15-17 45.8 44.8 43.8 44.8 1.0 2.2 46.0 47.6 45.6 46.4 1.1 2.3
H-5-12 44.4 42.2 43.0 43.2 1.1 2.6 48.2 47.6 48.0 47.9 0.3 0.6
H-10-12 43.5 44.4 43.3 43.7 0.6 1.3 48.1 47.8 49.2 48.4 0.7 1.5
H-15-12 44.8 44.4 44.0 44.4 0.4 0.9 48.0 48.0 48.8 48.3 0.5 1.0
H-5-3 42.4 42.8 42.4 42.5 0.2 0.5 46.4 48.8 48.0 47.7 1.2 2.6
H-10-3 42.0 45.6 44.0 43.9 1.8 4.1 48.0 47.2 48.4 47.9 0.6 1.3
H-15-3 46.4 46.8 45.2 46.1 0.8 1.8 51.2 50.8 50.4 50.8 0.4 0.8
176
Table A.17: Compressive Strength of Mortar Cubes at 3, 7 and 28 Days
Mix
Mortar Cube Compressive Strength (MPa)
3 Days 7 Days 28 Days
1 2 3 Avg. SD COV
(%) 1 2 3 Avg. SD
COV
(%) 1 2 3 Avg. SD
COV
(%)
GU 43.5 44.0 43.0 43.5 0.5 1.1 47.5 46.0 46.0 46.5 0.9 1.9 60.0 60.2 60.6 60.3 0.3 0.5
G-5-17 46.0 45.0 44.0 45.0 1.0 2.2 50.0 50.0 49.0 49.7 0.6 1.2 63.6 63.2 64.2 63.7 0.5 0.8
G-10-17 42.8 43.0 43.5 43.1 0.4 0.8 48.0 47.0 46.0 47.0 1.0 2.1 63.2 63.0 63.8 63.3 0.4 0.7
G-15-17 41.6 42.0 42.4 42.0 0.4 1.0 45.2 46.6 46.6 46.1 0.8 1.8 59.0 55.5 59.0 57.8 2.0 3.5
G-5-12 45.2 44.4 44.8 44.8 0.4 0.9 48.0 47.2 48.0 47.7 0.5 1.0 60.4 60.0 61.0 60.5 0.5 0.8
G-10-12 46.4 47.2 46.0 46.5 0.6 1.3 49.2 49.6 49.6 49.5 0.2 0.5 59.0 61.2 60.0 60.1 1.1 1.8
G-15-12 42.8 43.2 42.4 42.8 0.4 0.9 46.4 45.2 45.6 45.7 0.6 1.3 56.8 58.0 58.0 57.6 0.7 1.2
G-5-3 44.0 43.6 42.8 43.5 0.6 1.4 48.8 49.2 48.0 48.7 0.6 1.3 59.2 60.0 59.2 59.5 0.5 0.8
G-10-3 44.4 44.0 45.6 44.7 0.8 1.9 49.6 50.4 50.0 50.0 0.4 0.8 58.0 59.0 59.0 58.7 0.6 1.0
G-15-3 43.6 45.2 45.2 44.7 0.9 2.1 47.4 46.4 49.0 47.6 1.3 2.8 56.8 58.0 61.6 58.8 2.5 4.2
HE 53.1 49.2 52.2 51.5 2.0 4.0 53.6 52.0 51.6 52.4 1.1 2.0 61.2 64.8 63.0 63.0 1.8 2.9
H-5-17 52.2 51.2 52.4 51.9 0.6 1.2 54.4 52.0 52.8 53.1 1.2 2.3 60.8 67.2 67.6 65.2 3.8 5.9
H-10-17 52.8 53.6 52.4 52.9 0.6 1.2 54.0 55.4 54.0 54.5 0.8 1.5 65.2 61.6 65.6 64.1 2.2 3.4
H-15-17 49.6 49.8 50.2 49.9 0.3 0.6 53.0 52.0 52.5 52.5 0.5 1.0 66.0 66.4 65.0 65.8 0.7 1.1
H-5-12 51.2 50.8 50.0 50.7 0.6 1.2 53.9 52.0 53.6 53.2 1.0 1.9 63.3 63.8 63.9 63.7 0.3 0.5
H-10-12 50.8 50.8 54.0 51.9 1.8 3.6 53.0 53.9 54.2 53.7 0.6 1.2 66.0 67.0 66.0 66.3 0.6 0.9
H-15-12 55.0 52.8 54.0 53.9 1.1 2.0 52.8 55.6 58.0 55.5 2.6 4.7 68.0 67.0 68.0 67.7 0.6 0.9
H-5-3 51.2 51.0 51.6 51.3 0.3 0.6 51.6 56.4 57.6 55.2 3.2 5.8 62.4 64.4 66.0 64.3 1.8 2.8
H-10-3 52.0 52.0 52.8 52.3 0.5 0.9 57.6 58.8 56.8 57.7 1.0 1.7 67.6 66.4 67.6 67.2 0.7 1.0
H-15-3 56.0 54.6 54.8 55.1 0.8 1.4 58.0 58.4 59.6 58.7 0.8 1.4 70.4 70.4 67.6 69.5 1.6 2.3
177
Figure A.3: Relationship Between LF Reactivity, Ca(OH)2 Content and Degree of
Hydration at 16 Hours
0.5
0.55
0.6
0.65
0.7
11.8
12.2
12.6
13.0
13.4
13.8
14.2
0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Deg
ree
of
Hyd
rati
on
Ca(
OH
) 2 C
on
ten
t (w
t%)
LF Reactivity (wt%)
0% LF 5% LF 10% LF 15% LF
Ca(OH)2 Content
Degree of Hydration
178
A.7 Chapter 4 and 5 Results
A.7.1 Cement Paste and Mortar Results
Table A.18: Thermal Analysis Results of Cement Pastes Steam Cured at 55°C
Mix ID Sample #
Ca(OH)2 Content
(wt%) LF Reactivity (wt%)
Degree of
Hydration
16 Hrs. 28 Days 16 Hrs. 28 Days 16 Hrs. 28 Days
GU
1 7.80 8.36 0.02 0.28 0.57 0.70
2 7.81 8.42 0.01 0.31 0.55 0.68
3 7.77 8.34 0.00 0.29 0.54 0.69
Avg. 7.79 8.37 0.01 0.29 0.55 0.69
SD 0.02 0.04 0.01 0.01 0.02 0.01
COV(%) 0.3 0.5 --- 4.8 2.9 1.4
GU-17µm
1 7.53 8.33 0.44 1.06 0.52 0.66
2 7.51 8.17 0.47 1.14 0.53 0.64
3 7.64 8.31 0.44 1.13 0.54 0.68
Avg. 7.56 8.27 0.45 1.11 0.53 0.66
SD 0.07 0.09 0.02 0.04 0.01 0.02
COV(%) 0.9 1.0 3.7 3.8 1.7 3.0
GU-3µm
1 7.29 7.91 0.88 1.60 0.52 0.66
2 7.27 7.77 0.91 1.51 0.55 0.67
3 7.3 7.99 0.86 1.52 0.54 0.68
Avg. 7.29 7.89 0.88 1.54 0.54 0.67
SD 0.02 0.11 0.03 0.05 0.02 0.01
COV(%) 0.2 1.4 2.9 3.2 3.3 1.7
HE
1 7.74 8.28 0.30 0.49 0.59 0.74
2 7.69 8.1 0.27 0.49 0.6 0.73
3 7.6 8.29 0.26 0.46 0.61 0.73
Avg. 7.68 8.22 0.28 0.48 0.60 0.73
SD 0.07 0.11 0.02 0.02 0.01 0.00
COV(%) 0.9 1.3 6.8 3.6 2.1 0.5
HE-17µm
1 7.40 8.13 0.49 1.16 0.56 0.70
2 7.39 8.1 0.49 1.25 0.56 0.71
3 7.37 8.21 0.47 1.22 0.57 0.7
Avg. 7.39 8.15 0.48 1.21 0.56 0.70
SD 0.02 0.06 0.01 0.05 0.01 0.01
COV(%) 0.2 0.7 2.7 3.8 1.2 0.9
HE-3µm
1 7.00 7.86 0.94 1.81 0.58 0.71
2 6.97 7.78 0.92 1.7 0.56 0.7
3 7.03 7.8 0.89 1.89 0.56 0.72
Avg. 7.00 7.81 0.92 1.80 0.57 0.71
SD 0.03 0.04 0.03 0.10 0.01 0.01
COV(%) 0.4 0.5 2.7 5.3 2.5 1.4
179
Table A.19: Cube Compressive Strength of Mortars Steam Cured at 55°C
Mix ID Sample # Compressive Strength of Mortars (MPa)
12 hrs. 16 hrs. 3 days 7 days 28 days
GU
1 55.8 58.4 65.3 68.9 82.0
2 51.0 56.3 67.2 69.9 78.9
3 54.0 58.1 64.3 70.0 77.9
Avg. 53.6 57.6 65.6 69.6 79.6
SD 2.4 1.1 1.5 0.6 2.1
COV(%) 4.5 2.0 2.2 0.9 2.7
GU-17µm
1 61.2 64.5 70.5 72.1 82.4
2 62.3 67.4 73.2 74.5 80.6
3 60.9 64.9 71.1 73.0 83.4
Avg. 61.5 65.6 71.6 73.2 82.1
SD 0.7 1.6 1.4 1.2 1.4
COV(%) 1.2 2.4 2.0 1.7 1.7
GU-3µm
1 64.8 68.6 71.7 73.3 86.7
2 61.3 69.3 74.6 78.0 84.1
3 63.1 70.3 74.5 76.7 81.2
Avg. 63.1 69.4 73.6 76.0 84.0
SD 1.8 0.9 1.6 2.4 2.8
COV(%) 2.8 1.2 2.2 3.2 3.3
HE
1 61.1 62.5 68.3 72.0 79.4
2 55.3 66.6 68.0 70.1 78.3
3 56.8 64.1 68.9 73.9 83.1
Avg. 57.7 64.4 68.4 72.0 80.3
SD 3.0 2.1 0.5 1.9 2.5
COV(%) 5.2 3.2 0.7 2.6 3.1
HE-17µm
1 59.8 67.0 73.9 74.9 82.8
2 59.3 65.2 70.1 71.2 80.2
3 60.9 68.2 70.4 75.3 81.2
Avg. 60.0 66.8 71.5 73.8 81.4
SD 0.8 1.5 2.1 2.3 1.3
COV(%) 1.4 2.3 2.9 3.1 1.6
HE-3µm
1 60.2 67.1 73.4 78.3 83.1
2 64.2 70.5 77.6 78.5 82.3
3 62.0 70.0 77.0 76.8 83.4
Avg. 62.1 69.2 76.0 77.9 82.9
SD 2.0 1.8 2.3 0.9 0.6
COV(%) 3.2 2.7 3.0 1.2 0.7
180
A.7.2 Fresh Properties of Concrete
Table A.20: Fresh Properties of Concrete (Yield = 1 m3 ± 0.012 m3)
Mix ID
Plastic Air
Content
(%)
Plastic
Density
(kg/m3)
Slump L-box
(H2/H1)
Column
Segregation
(%) Flow
(mm)
T50
(sec) VSI
J-Ring
(mm)
GU 5.1* 2395 680 4 0.5 660 0.67 2.5
GU-17µm 5.4* 2431 650 4 0 635 0.58 1.5
GU-3µm 5.1* 2439 660 5 0 640 0.50 1.0
HE 5.2* 2444 650 5 0.5 638 0.64 1.6
HE-17µm 5.1* 2439 680 4 0 660 0.56 1.5
HE-3µm 5.3* 2443 650 5 0 630 0.53 0.8
GUL 5.7 --- 695 --- 0.5 --- --- ---
HS 4.9 --- 630 --- 0.5 --- --- ---
HS-17µm 5.3 --- 685 --- 0 --- --- ---
HS-3µm 5.0 --- 645 --- 0 --- --- ---
* Average of two values measured in Chapter 4 and 5.
181
A.7.3 Mechanical Properties of Concrete
Table A.21: Elastic Modulus Values of Concrete Steam Cured at 55°C
Mix ID Sample # Elastic Modulus (GPa)
12 hrs. 16 hrs. 3 days 7 days 28 days
GU
1 26.0 32.9 35.0 38.0 40.9
2 25.9 32.0 35.4 37.0 40.3
3 26.3 32.5 34.7 37.0 41.0
Avg. 26.1 32.5 35.0 37.3 40.7
SD 0.2 0.5 0.4 0.6 0.4
COV(%) 0.8 1.4 1.0 1.6 0.9
GU-17µm
1 27.9 33.5 36.0 38.0 40.0
2 26.9 32.0 35.6 37.0 41.9
3 27.4 32.9 35.1 36.4 41.0
Avg. 27.4 32.8 35.6 37.1 41.0
SD 0.5 0.8 0.5 0.8 1.0
COV(%) 1.8 2.3 1.3 2.2 2.3
GU-3µm
1 31.3 34.8 36.0 38.9 41.6
2 31.6 34.6 36.5 37.0 40.0
3 31.0 34.9 35.5 38.3 41.3
Avg. 31.3 34.8 36.0 38.1 41.0
SD 0.3 0.2 0.5 1.0 0.9
COV(%) 1.0 0.4 1.4 2.6 2.1
HE
1 31.9 36.0 38.0 39.0 42.0
2 31.0 34.0 36.5 39.5 40.9
3 32.0 35.3 36.9 38.5 41.0
Avg. 31.6 35.1 37.1 39.0 41.3
SD 0.6 1.0 0.8 0.5 0.6
COV(%) 1.7 2.9 2.1 1.3 1.5
HE-17µm
1 33.9 35.9 36.7 38.9 41.0
2 32.3 35.0 38.0 40.0 40.0
3 33.9 35.4 37.0 37.8 40.9
Avg. 33.4 35.4 37.2 38.9 40.6
SD 0.9 0.5 0.7 1.1 0.6
COV(%) 2.8 1.3 1.8 2.8 1.4
HE-3µm
1 35.1 37.0 38.4 40.8 41.7
2 34.9 36.0 39.0 39.0 41.0
3 33.1 35.4 37.8 39.4 42.0
Avg. 34.4 36.1 38.4 39.7 41.6
SD 1.1 0.8 0.6 1.0 0.5
COV(%) 3.2 2.2 1.6 2.4 1.2
182
Table A.22: Hardened Density of Concrete Steam Cured at 55°C
Mix ID Sample # Density (kg/m3)
12 hrs. 16 hrs. 3 days 7 days 28 days
GU
1 2360 2360 2370 2370 2380
2 2350 2341 2355 2360 2380
3 2356 2340 2330 2350 2365
Avg. 2355 2347 2352 2360 2375
SD 5.0 11.3 20.2 10.0 8.7
COV(%) 0.2 0.5 0.9 0.4 0.4
GU-17µm
1 2370 2350 2360 2360 2390
2 2380 2340 2350 2340 2380
3 2330 2345 2357 2360 2380
Avg. 2360 2345 2356 2353 2383
SD 26.5 5.0 5.1 11.6 5.8
COV(%) 1.1 0.2 0.2 0.5 0.2
GU-3µm
1 2470 2460 2450 2470 2460
2 2460 2470 2440 2455 2460
3 2400 2460 2430 2440 2450
Avg. 2443 2463 2440 2455 2457
SD 37.9 5.8 10.0 15.0 5.8
COV(%) 1.6 0.2 0.4 0.6 0.2
HE
1 2400 2445 2430 2445 2420
2 2415 2400 2465 2400 2400
3 2400 2400 2400 2400 2470
Avg. 2405 2415 2432 2415 2430
SD 8.7 26.0 32.5 26.0 36.1
COV(%) 0.4 1.1 1.3 1.1 1.5
HE-17µm
1 2420 2445 2460 2480 2430
2 2430 2410 2430 2450 2450
3 2410 2390 2400 2400 2440
Avg. 2420 2415 2430 2443 2440
SD 10.0 27.8 30.0 40.4 10.0
COV(%) 0.4 1.2 1.2 1.7 0.4
HE-3µm
1 2460 2460 2450 2450 2470
2 2460 2470 2460 2445 2450
3 2450 2450 2440 2445 2460
Avg. 2457 2460 2450 2447 2460
SD 5.8 10.0 10.0 2.9 10.0
COV(%) 0.2 0.4 0.4 0.1 0.4
183
Table A.23: Compressive Strength of Concrete Steam Cured at 55°C
Mix ID Sample # Compressive Strength (MPa)
12 hrs. 16 hrs. 3 days 7 days 28 days 300 days
GU
1 38.8 48.6 60.2 65.3 72.6 88.0
2 37.0 46.9 57.9 63.6 71.1 90.4
3 37.8 47.9 58.7 64.5 73.8 89.6
Avg. 37.9 47.8 58.9 64.5 72.5 89.3
SD 0.9 0.9 1.2 0.9 1.4 1.2
COV(%) 2.4 1.8 2.0 1.3 1.9 1.4
GU-17µm
1 38.9 51.3 60.4 63.1 70.2 85.7
2 39.6 48.9 59.5 61.2 68.4 82.8
3 39.0 49.7 58.1 62.2 69.0 83.0
Avg. 39.2 50.0 59.3 62.2 69.2 83.8
SD 0.4 1.2 1.2 1.0 0.9 1.6
COV(%) 1.0 2.4 2.0 1.5 1.3 1.9
GU-3µm
1 46.0 56.9 63.8 66.8 74.7 87.6
2 44.4 55.3 60.0 64.4 71.8 84.5
3 46.0 53.9 62.0 66.4 73.4 85.6
Avg. 45.5 55.4 61.9 65.9 73.3 85.9
SD 0.9 1.5 1.9 1.3 1.5 1.6
COV(%) 2.0 2.7 3.1 2.0 2.0 1.8
HE
1 52.4 60.5 66.5 66.7 73.7 84.4
2 53.6 56.7 64.6 68.0 70.3 88.6
3 53.0 57.6 62.1 69.2 69.9 85.0
Avg. 53.0 58.3 64.4 68.0 71.3 86.0
SD 0.6 2.0 2.2 1.3 2.1 2.3
COV(%) 1.1 3.4 3.4 1.8 2.9 2.6
HE-17µm
1 53.0 54.6 63.6 67.7 70.1 83.5
2 51.0 57.7 63.6 64.6 70.1 80.6
3 51.2 56.4 60.6 66.4 73.2 82.3
Avg. 51.7 56.2 62.6 66.2 71.1 82.1
SD 1.1 1.6 1.7 1.5 1.8 1.5
COV(%) 2.1 2.8 2.8 2.3 2.6 1.8
HE-3µm
1 55.1 58.6 62.1 69.6 74.6 85.5
2 54.0 59.0 62.8 69.3 70.7 82.0
3 54.0 62.5 66.4 66.4 72.0 84.2
Avg. 54.4 60.0 63.8 68.4 72.4 83.9
SD 0.6 2.2 2.3 1.8 2.0 1.8
COV(%) 1.2 3.6 3.6 2.6 2.7 2.1
184
Table A.23 (Continued): Compressive Strength of Concrete Steam Cured at 55°C
Mix ID Sample # Compressive Strength (MPa)
16 hrs. 3 days 7 days 28 days 300 days
GUL
1 54.3 61.2 64.6 72.9 86.1
2 54.3 61.2 64.6 69.4 86.0
3 57.4 58.0 67.9 71.0 82.6
Avg. 55.3 60.1 65.7 71.1 84.9
SD 1.8 1.9 1.9 1.8 2.0
COV(%) 3.3 3.1 2.9 2.5 2.3
HS
1 50.5 57.8 67.1 70.4 86.0
2 48.0 57.8 67.1 70.4 82.4
3 49.6 60.7 64.1 73.5 84.5
Avg. 49.4 58.8 66.1 71.4 84.3
SD 1.3 1.7 1.7 1.8 1.8
COV(%) 2.6 2.8 2.6 2.5 2.1
HS-17µm
1 51.2 61.6 67.0 70.3 85.6
2 48.6 58.8 67.0 70.3 82.1
3 50.2 60.4 70.1 73.4 84.1
Avg. 50.0 60.2 68.0 71.3 83.9
SD 1.3 1.4 1.8 1.8 1.8
COV(%) 2.6 2.3 2.6 2.6 2.1
HS-3µm
1 52.0 59.4 68.9 75.0 88.6
2 52.0 59.4 65.8 71.6 85.5
3 55.1 62.6 67.4 73.6 86.5
Avg. 53.0 60.5 67.4 73.4 86.9
SD 1.8 1.9 1.6 1.7 1.6
COV(%) 3.4 3.1 2.3 2.3 1.8
185
Table A.24: Compressive Strength of Concrete Steam Cured at 70°C
Mix ID Sample # Compressive Strength (MPa)
16 hrs. 3 days 7 days 28 days 300 days
GU
1 60.8 61.7 67.1 71.2 84.1
2 58.4 61.7 64.6 68.7 81.5
3 60.0 64.3 66.2 70.3 83.1
Avg. 59.7 62.6 66.0 70.1 82.9
SD 1.2 1.5 1.3 1.3 1.3
COV(%) 2.1 2.4 1.9 1.8 1.6
GU-17µm
1 62.3 62.8 66.2 69.5 80.6
2 59.8 62.8 63.6 69.5 80.6
3 61.4 65.6 65.2 66.7 77.6
Avg. 61.2 63.7 65.0 68.6 79.6
SD 1.3 1.6 1.3 1.6 1.7
COV(%) 2.1 2.5 2.0 2.4 2.2
GU-3µm
1 63.7 63.0 68.5 72.2 82.1
2 61.0 63.0 65.8 72.2 79.5
3 62.6 65.9 67.4 69.2 81.1
Avg. 62.4 64.0 67.2 71.2 80.9
SD 1.4 1.7 1.4 1.7 1.3
COV(%) 2.2 2.6 2.1 2.4 1.6
HE
1 63.8 68.0 67.1 68.0 84.1
2 59.6 66.5 67.0 72.1 80.1
3 61.0 64.3 70.5 70.0 81.5
Avg. 61.5 66.3 68.2 70.0 81.9
SD 2.1 1.9 2.0 2.1 2.1
COV(%) 3.5 2.8 2.9 2.9 2.5
HE-17µm
1 61.4 63.4 67.4 67.3 80.5
2 58.6 63.4 67.4 67.3 77.0
3 60.2 66.4 64.3 70.4 79.0
Avg. 60.0 64.4 66.3 68.3 78.8
SD 1.4 1.8 1.8 1.8 1.7
COV(%) 2.3 2.7 2.7 2.6 2.2
186
Table A.24 (Continued): Compressive Strength of Concrete Steam Cured at 70°C
Mix ID Sample # Compressive Strength (MPa)
16 hrs. 3 days 7 days 28 days 300 days
HE-3µm
1 64.2 69.2 67.0 74.5 80.0
2 60.1 68.2 67.8 70.1 76.0
3 62.4 65.1 71.5 72.3 77.7
Avg. 62.2 67.5 68.8 72.3 77.9
SD 2.0 2.1 2.4 2.2 2.0
COV(%) 3.3 3.2 3.5 3.0 2.6
GUL
1 62.0 64.0 65.1 69.4 80.0
2 58.5 61.0 65.1 69.0 80.0
3 60.6 62.6 68.4 72.8 83.0
Avg. 60.4 62.5 66.2 70.4 81.0
SD 1.8 1.5 1.9 2.1 1.7
COV(%) 2.9 2.5 2.9 3.0 2.2
HS
1 58.6 64.4 67.0 72.8 81.9
2 55.9 64.4 70.0 72.6 78.9
3 57.5 67.4 70.0 75.9 80.1
Avg. 57.3 65.4 69.0 73.8 80.3
SD 1.3 1.7 1.7 1.9 1.5
COV(%) 2.3 2.6 2.5 2.5 1.9
HS-17µm
1 59.3 62.3 68.6 73.1 77.7
2 56.6 65.1 71.5 72.7 80.4
3 58.2 63.9 70.2 69.9 79.3
Avg. 58.0 63.8 70.1 71.9 79.1
SD 1.4 1.4 1.5 1.7 1.4
COV(%) 2.4 2.2 2.1 2.4 1.7
HS-3µm
1 61.7 66.0 67.0 70.6 76.1
2 58.0 69.1 70.6 70.6 79.7
3 60.2 67.1 69.0 74.0 78.2
Avg. 60.0 67.4 68.9 71.7 78.0
SD 1.9 1.6 1.8 2.0 1.8
COV(%) 3.1 2.4 2.6 2.7 2.3
187
Table A.25: Compressive Strength of Concrete Steam Cured at 82°C
Mix ID Sample # Compressive Strength (MPa)
16 hrs. 3 days 7 days 28 days 300 days
GU
1 71.5 71.2 71.5 72.8 79.3
2 69.0 72.1 71.9 73.7 80.7
3 70.6 69.6 74.2 71.2 82.1
Avg. 70.4 71.0 72.5 72.6 80.7
SD 1.3 1.3 1.5 1.3 1.4
COV(%) 1.8 1.8 2.0 1.8 1.7
GU-17µm
1 69.6 71.2 70.0 71.5 82.3
2 70.6 68.6 70.4 72.6 82.3
3 68.0 70.2 72.9 69.9 79.3
Avg. 69.4 70.0 71.1 71.3 81.3
SD 1.3 1.3 1.5 1.3 1.7
COV(%) 1.9 1.9 2.2 1.9 2.1
GU-3µm
1 70.0 73.3 73.5 75.5 83.4
2 70.0 70.5 74.7 72.7 84.8
3 73.0 72.1 71.9 74.3 81.8
Avg. 71.0 72.0 73.4 74.2 83.3
SD 1.7 1.4 1.4 1.4 1.5
COV(%) 2.4 2.0 1.9 1.9 1.8
HE
1 70.1 73.3 72.0 76.0 81.0
2 72.5 70.0 72.0 75.0 77.7
3 68.3 70.9 76.1 72.0 79.0
Avg. 70.3 71.4 73.4 74.3 79.2
SD 2.1 1.7 2.4 2.1 1.7
COV(%) 3.0 2.4 3.2 2.8 2.1
HE-17µm
1 65.8 70.5 72.3 71.6 78.0
2 65.8 67.6 72.2 71.0 75.5
3 68.9 69.2 69.2 74.6 77.1
Avg. 66.8 69.1 71.2 72.4 76.9
SD 1.8 1.5 1.8 1.9 1.3
COV(%) 2.7 2.1 2.5 2.6 1.7
188
Table A.25 (Continued): Compressive Strength of Concrete Steam Cured at 82°C
Mix ID Sample # Compressive Strength (MPa)
16 hrs. 3 days 7 days 28 days 300 days
HE-3µm
1 72.1 70.4 72.8 74.0 76.5
2 71.2 73.7 73.6 73.0 76.9
3 68.0 70.0 69.4 70.5 80.3
Avg. 70.4 71.4 71.9 72.5 77.9
SD 2.1 2.0 2.2 1.8 2.1
COV(%) 3.0 2.8 3.1 2.5 2.7
GUL
1 65.2 70.5 69.1 72.5 81.6
2 68.8 67.9 69.6 70.4 82.1
3 67.3 69.5 72.5 71.5 78.9
Avg. 67.1 69.3 70.4 71.5 80.9
SD 1.8 1.3 1.8 1.1 1.7
COV(%) 2.7 1.9 2.6 1.5 2.1
HS
1 68.4 66.4 69.2 71.6 78.0
2 65.6 69.2 69.2 74.5 81.0
3 67.2 68.0 72.3 73.3 79.6
Avg. 67.1 67.9 70.2 73.1 79.5
SD 1.4 1.4 1.8 1.5 1.5
COV(%) 2.1 2.1 2.5 2.0 1.9
HS-17µm
1 68.6 64.9 68.2 70.0 77.0
2 65.7 66.9 68.9 71.6 80.0
3 67.3 68.9 66.5 72.1 79.0
Avg. 67.2 66.9 67.9 71.2 78.7
SD 1.5 2.0 1.2 1.1 1.5
COV(%) 2.2 3.0 1.8 1.5 1.9
HS-3µm
1 68.4 66.7 70.1 70.1 82.0
2 69.2 67.0 70.8 73.1 82.0
3 65.7 70.4 67.4 72.4 79.0
Avg. 67.8 68.0 69.4 71.9 81.0
SD 1.8 2.0 1.8 1.6 1.7
COV(%) 2.7 3.0 2.6 2.2 2.2
189
Table A.26: UPV Results of Concrete Steam Cured at 55°C
Mix ID Sample # UPV (m/s)
12 hrs. 16 hrs. 3 days 7 days 28 days 300 days
GU
1 4200 4480 4600 4909 5130 5460
2 4230 4500 4720 4839 5180 5260
3 4200 4370 4700 4810 5001 5270
Avg. 4210 4450 4673 4853 5104 5330
SD 17 70.0 64.3 50.9 92.4 112.7
COV(%) 0.4 1.6 1.4 1.0 1.8 2.1
GU-17µm
1 4456 4624 4790 4772 5196 5330
2 4490 4690 4820 4780 5086 5490
3 4500 4790 4610 4810 4958 5416
Avg. 4482 4701 4740 4787 5080 5412
SD 23 83.6 113.6 20.0 119.1 80.1
COV(%) 0.5 1.8 2.4 0.4 2.3 1.5
GU-3µm
1 4700 4759 4920 5010 5120 5536
2 4680 4891 4900 4940 5080 5400
3 4706 4750 4850 4874 5340 5490
Avg. 4695 4800 4890 4941 5180 5475
SD 14 79.1 36.1 68.0 140.0 69.2
COV(%) 0.3 1.6 0.7 1.4 2.7 1.3
HE
1 4720 5000 4871 5020 5230 5300
2 4690 4910 5129 5080 5130 5330
3 4680 4850 4940 4962 5030 5240
Avg. 4697 4920 4980 5021 5130 5290
SD 21 75.5 134.0 59.0 100.0 45.8
COV(%) 0.4 1.5 2.7 1.2 1.9 0.9
HE-17µm
1 4850 4870 4903 4936 5190 5061
2 4770 5000 5120 5068 5120 5275
3 4780 5092 4976 5152 5005 5318
Avg. 4800 4987 5000 5052 5105 5218
SD 44 111.5 110.4 109.0 93.4 137.3
COV(%) 0.9 2.2 2.2 2.2 1.8 2.6
HE-3µm
1 4900 5000 5110 4990 5230 5243
2 4880 5120 5024 5259 5120 5300
3 4880 4880 5062 5069 5064 5312
Avg. 4887 5000 5065 5106 5138 5285
SD 12 120.0 43.1 138.4 84.5 37.1
COV(%) 0.2 2.4 0.9 2.7 1.6 0.7
190
Table A.26 (Continued): UPV Results of Concrete Steam Cured at 55°C
Mix ID Sample # UPV (m/s)
16 hrs. 3 days 7 days 28 days 300 days
HE-3µm
1 5000 5110 4990 5230 5243
2 5120 5024 5259 5120 5300
3 4880 5062 5069 5064 5312
Avg. 5000 5065 5106 5138 5285
SD 120.0 43.1 138.4 84.5 37.1
COV(%) 2.4 0.9 2.7 1.6 0.7
GUL
1 4702 4653 4830 5000 5214
2 4640 4700 4720 5030 5326
3 4736 4747 4816 5120 5420
Avg. 4693 4700 4789 5050 5320
SD 48.7 47.0 59.9 62.4 103.3
COV(%) 1.0 1.0 1.3 1.2 1.9
HS
1 4840 4740 4831 5000 5290
2 4700 4884 4919 5010 5410
3 4662 4812 4950 5046 5484
Avg. 4734 4812 4900 5019 5395
SD 93.7 72.2 61.4 24.2 97.9
COV(%) 2.0 1.5 1.3 0.5 1.8
HS-17µm
1 4680 4840 4685 5090 5073
2 4616 4730 5010 5000 5315
3 4730 4770 4855 4956 5254
Avg. 4675 4780 4850 5015 5214
SD 57.1 55.7 162.5 68.3 125.6
COV(%) 1.2 1.2 3.4 1.4 2.4
HS-3µm
1 4523 4640 4838 5020 5016
2 4641 4670 4700 4950 5320
3 4612 4610 4710 4880 5243
Avg. 4592 4640 4749 4950 5193
SD 61.4 30.0 77.0 70.0 157.6
COV(%) 1.3 0.6 1.6 1.4 3.0
191
Table A.27: UPV Results of Concrete Steam Cured at 70°C
Mix ID Sample # UPV (m/s)
16 hrs. 3 days 7 days 28 days 300 days
GU
1 4733 4812 4820 5100 5430
2 4567 4826 4800 5056 5339
3 4617 4618 5011 4958 5221
Avg. 4639 4752 4877 5038 5330
SD 85.2 116.3 116.5 72.7 104.8
COV(%) 1.8 2.4 2.4 1.4 2.0
GU-17µm
1 4768 4790 4978 5180 5489
2 4654 4867 4900 5000 5304
3 4684 4710 4711 5126 5197
Avg. 4702 4789 4863 5102 5330
SD 59.1 78.5 137.3 92.4 147.7
COV(%) 1.3 1.6 2.8 1.8 2.8
GU-3µm
1 4839 4698 4950 5000 5120
2 4678 4856 4900 4910 5340
3 4589 4891 4853 5015 5530
Avg. 4702 4815 4901 4975 5330
SD 126.7 102.8 48.5 56.8 205.2
COV(%) 2.7 2.1 1.0 1.1 3.8
HE
1 4834 4856 4812 4910 5179
2 4745 4734 4800 5003 5189
3 4527 4660 4824 4976 5211
Avg. 4702 4750 4812 4963 5193
SD 158.0 99.0 12.0 47.8 16.4
COV(%) 3.4 2.1 0.2 1.0 0.3
HE-17µm
1 4720 4870 4890 5000 5200
2 4730 4750 4820 4924 5120
3 4590 4630 4840 5001 5148
Avg. 4680 4750 4850 4975 5156
SD 78.1 120.0 36.1 44.2 40.6
COV(%) 1.7 2.5 0.7 0.9 0.8
192
Table A.27 (Continued): UPV Results of Concrete Steam Cured at 70°C
Mix ID Sample # UPV (m/s)
16 hrs. 3 days 7 days 28 days 300 days
HE-3µm
1 4768 4869 4898 4900 5300
2 4656 4759 4800 4887 5230
3 4676 4766 4765 4916 5142
Avg. 4700 4798 4821 4901 5224
SD 59.7 61.6 68.9 14.5 79.2
COV(%) 1.3 1.3 1.4 0.3 1.5
GUL
1 4830 4812 4900 5000 5390
2 4745 4889 4845 4967 5249
3 4681 4849 4895 4973 5264
Avg. 4752 4850 4880 4980 5301
SD 74.7 38.5 30.4 17.6 77.4
COV(%) 1.6 0.8 0.6 0.4 1.5
HS
1 4580 4638 4730 5000 5400
2 4434 4600 4600 4978 5389
3 4585 4559 4725 5007 5255
Avg. 4533 4599 4685 4995 5348
SD 85.8 39.5 73.7 15.1 80.7
COV(%) 1.9 0.9 1.6 0.3 1.5
HS-17µm
1 4500 4700 4967 5023 5400
2 4400 4750 4800 4900 5340
3 4567 4617 4858 5038 5232
Avg. 4489 4689 4875 4987 5324
SD 84.0 67.2 84.8 75.7 85.1
COV(%) 1.9 1.4 1.7 1.5 1.6
HS-3µm
1 4489 4789 4835 4976 5400
2 4387 4656 4658 4800 5200
3 4396 4622 4853 4894 5024
Avg. 4424 4689 4782 4890 5208
SD 56.5 88.3 107.8 88.1 188.1
COV(%) 1.3 1.9 2.3 1.8 3.6
193
Table A.28: UPV Results of Concrete Steam Cured at 82°C
Mix ID Sample # UPV (m/s)
16 hrs. 3 days 7 days 28 days 300 days
GU
1 4800 4890 5000 5000 5438
2 4723 4800 4900 4967 5398
3 4679 4860 4803 5033 5238
Avg. 4734 4850 4901 5000 5358
SD 61.2 45.8 98.5 33.0 105.8
COV(%) 1.3 0.9 2.0 0.7 2.0
GU-17µm
1 4930 4812 4965 5000 5400
2 4800 4857 4834 5012 5349
3 4676 4731 4904 5180 5454
Avg. 4802 4800 4901 5064 5401
SD 127.0 63.9 65.6 100.6 52.5
COV(%) 2.6 1.3 1.3 2.0 1.0
GU-3µm
1 4949 4978 5000 5234 5500
2 4800 4857 4923 5100 5400
3 4954 4865 4891 5092 5522
Avg. 4901 4900 4938 5142 5474
SD 87.5 67.7 56.0 79.8 65.0
COV(%) 1.8 1.4 1.1 1.6 1.2
HE
1 4756 4834 4800 5000 5156
2 4700 4800 4834 4998 5180
3 4665 4733 4985 5038 5243
Avg. 4707 4789 4873 5012 5193
SD 45.9 51.4 98.5 22.5 44.9
COV(%) 1.0 1.1 2.0 0.4 0.9
HE-17µm
1 4800 4890 4900 5000 5300
2 4750 4800 4967 5046 5278
3 4856 4944 4845 4954 5292
Avg. 4802 4878 4904 5000 5290
SD 53.0 72.7 61.1 46.0 11.1
COV(%) 1.1 1.5 1.2 0.9 0.2
194
Table A.28 (Continued): UPV Results of Concrete Steam Cured at 82°C
Mix ID Sample # UPV (m/s)
16 hrs. 3 days 7 days 28 days 300 days
HE-3µm
1 4712 4778 4854 5000 5323
2 4790 4756 4776 4923 5200
3 4874 4836 4992 5038 5194
Avg. 4792 4790 4874 4987 5239
SD 81.0 41.3 109.4 58.6 72.8
COV(%) 1.7 0.9 2.2 1.2 1.4
GUL
1 4734 4800 4900 5000 5312
2 4770 4900 4967 4978 5234
3 4638 4700 4803 5022 5312
Avg. 4714 4800 4890 5000 5286
SD 68.2 100.0 82.5 22.0 45.0
COV(%) 1.4 2.1 1.7 0.4 0.9
HS
1 4510 4700 4812 5000 5320
2 4595 4600 4790 4900 5123
3 4656 4761 4753 5022 5136
Avg. 4587 4687 4785 4974 5193
SD 73.3 81.3 29.8 65.0 110.2
COV(%) 1.6 1.7 0.6 1.3 2.1
HS-17µm
1 4600 4723 4857 4956 5120
2 4690 4756 4812 4800 5200
3 4546 4615 4686 4815 5247
Avg. 4612 4698 4785 4857 5189
SD 72.7 73.7 88.6 86.1 64.2
COV(%) 1.6 1.6 1.9 1.8 1.2
HS-3µm
1 4690 4698 4856 4956 5320
2 4600 4734 4700 4980 5200
3 4696 4923 4793 4680 5185
Avg. 4662 4785 4783 4872 5235
SD 53.8 120.9 78.5 166.7 74.0
COV(%) 1.2 2.5 1.6 3.4 1.4
195
A.7.4 Transport Properties of Concrete
Table A.29: Rapid Chloride Permeability Values of Concrete at 28 Days
Mix ID Steam Curing
Temp.
RCPT (Coulombs)
Sample # Average SD COV (%)
1 2 3
GU
55°C
598 638 612 616 20 3.3
GU-17µm 442 437 446 442 5 1.0
GU-3µm 415 409 409 411 3 0.8
HE 455 466 494 472 20 4.3
HE-17µm 408 368 388 388 20 5.2
HE-3µm 330 350 310 330 20 6.1
GUL 760 700 685 715 40 5.6
HS 600 649 581 610 35 5.8
HS-17µm 580 600 590 590 10 1.7
HS-3µm 530 534 556 540 14 2.6
GU
70°C
1010 1080 1060 1050 36 3.4
GU-17µm 1000 940 983.5 975 31 3.2
GU-3µm 830 875 860 855 23 2.7
HE 926 990 1037.5 985 56 5.7
HE-17µm 1100 997 1008 1035 57 5.5
HE-3µm 900 923 991 938 47 5.0
GUL 1140 1049 1129 1106 50 4.5
HS 1230 1212 1323 1255 60 4.7
HS-17µm 1230 1198 1172 1200 29 2.4
HS-3µm 1175 1110 1168 1151 36 3.1
GU
82°C
1130 1189 1168.5 1163 30 2.6
GU-17µm 1069 1011 1115 1065 52 4.9
GU-3µm 945 978 985.5 970 22 2.2
HE 1150 1100 1066.5 1106 42 3.8
HE-17µm 1167 1120 1053.5 1114 57 5.1
HE-3µm 1000 1030 1120 1050 62 5.9
GUL 1279 1253 1152 1228 67 5.5
HS 1492 1367 1443 1434 63 4.4
HS-17µm 1311 1369 1370 1350 34 2.5
HS-3µm 1336 1356 1278.5 1324 40 3.0
196
Table A.30: Rapid Chloride Permeability Values of Concrete at 300 Days
Mix ID Steam Curing
Temp.
RCPT (Coulombs)
Sample # Average SD COV (%)
1 2 3
GU
55°C
490 470 480 480 10 2.1
GU-17µm 400 420 386 402 17 4.3
GU-3µm 200 198 199 199 1 0.5
HE 412 410 378 400 19 4.8
HE-17µm 324 360 366 350 23 6.5
HE-3µm 279 300 321 300 21 7.0
GUL 511 515 555 527 24 4.6
HS 570 540 516 542 27 5.0
HS-17µm 515 490 495 500 13 2.6
HS-3µm 460 440 444 448 11 2.4
GU
70°C
870 866 814 850 31 3.7
GU-17µm 867 814 896 859 42 4.8
GU-3µm 630 640 629 633 6 1.0
HE 889 860 822 857 34 3.9
HE-17µm 790 839 738 789 51 6.4
HE-3µm 550 600 569 573 25 4.4
GUL 690 710 640 680 36 5.3
HS 800 760 831 797 36 4.5
HS-17µm 770 730 765 755 22 2.9
HS-3µm 798 765 792 785 18 2.2
GU
82°C
927 900 915 914 14 1.5
GU-17µm 800 843 793 812 27 3.3
GU-3µm 744 732 732 736 7 0.9
HE 1000 1040 948 996 46 4.6
HE-17µm 820 840 728 796 60 7.5
HE-3µm 690 630 687 669 34 5.1
GUL 819 790 731 780 45 5.7
HS 1078 1000 1069 1049 43 4.1
HS-17µm 879 830 838 849 26 3.1
HS-3µm 717 711 672 700 24 3.5
197
A.7.5 Durability Performance of Concrete/Mortar
Table A.31: Linear Shrinkage of Concrete Made of GU Cement
GU GU-17µm GU-3µm
Age
(Day)
Avg.
Shrinkage
(%)
SD COV
(%)
Age
(Day)
Avg.
Shrinkage
(%)
SD COV
(%)
Age
(Day)
Avg.
Shrinkage
(%)
SD COV
(%)
0 0.000 --- --- 0 0.000 --- --- 0.0 0.000 --- ---
2 0.005 0.002 0.3 4 0.009 0.001 6.7 1.0 0.002 0.000 5.0
3 0.008 0.001 5.7 5 0.010 0.006 0.5 2.5 0.004 0.001 0.3
7 0.013 0.007 0.5 7 0.013 0.001 4.8 6.5 0.009 0.000 1.1
8 0.014 0.001 4.8 11 0.016 0.007 0.5 9.8 0.012 0.002 0.2
9 0.015 0.007 0.4 14 0.017 0.000 1.8 14.3 0.016 0.000 1.4
13 0.018 0.001 3.2 18 0.018 0.004 0.2 16.8 0.017 0.004 0.2
17 0.020 0.007 0.3 21 0.019 0.001 4.7 21.9 0.018 0.000 1.7
21 0.022 0.001 4.3 26 0.020 0.007 0.3 29.0 0.019 0.004 0.2
24 0.023 0.008 0.3 33 0.022 0.001 3.7 63.3 0.022 0.001 4.6
29 0.024 0.001 3.6 67 0.025 0.006 0.2
36 0.025 0.000 3.8
70 0.028 0.007 0.2
Table A.32: Linear Shrinkage of Concrete Made of HE Cement
HE HE-17µm HE-3µm
Age
(Days)
Avg.
Shrinkage
(%)
SD COV
(%)
Age
(Days
Avg.
Shrinkage
(%)
SD COV
(%)
Age
(Days
Avg.
Shrinkage
(%)
SD COV
(%)
0 0.000 --- --- 0 0.000 --- --- 0 0.000 --- ---
2 0.005 0.000 2.1 1 0.003 0.000 3.3 2 0.005 0.000 8.0
6 0.009 0.004 0.5 3 0.006 0.007 1.1 6 0.010 0.001 0.1
13 0.016 0.001 5.4 7 0.011 0.000 3.4 9 0.012 0.001 5.0
16 0.017 0.006 0.4 10 0.013 0.003 0.2 14 0.015 0.006 0.4
21 0.019 0.000 2.1 15 0.016 0.001 6.3 21 0.017 0.001 3.5
28 0.021 0.007 0.4 22 0.019 0.003 0.1 55 0.021 0.004 0.2
62 0.024 0.001 2.5 56 0.023 0.002 7.8
198
Table A.33: Sulfate Resistance of Mortar Made of GU Cement
Age
(Weeks)
GU GU-17µm GU-3µm
Average
Expansion
(%)
SD COV
(%)
Average
Expansion
(%)
SD COV
(%)
Average
Expansion
(%)
SD COV
(%)
0.0 0.000 --- --- 0.000 --- --- 0.000 --- ---
0.9 0.013 0.0015 11.5 0.015 0.0013 8.2 0.016 0.0009 5.4
2.0 0.015 0.0010 6.7 0.019 0.0014 8.3 0.019 0.0005 2.6
3.0 0.018 0.0004 1.9 0.021 0.0019 9.2 0.021 0.0007 3.4
4.0 0.020 0.0007 4.5 0.022 0.0025 13.2 0.022 0.0008 3.8
6.0 0.023 0.0006 2.8 0.024 0.0025 10.4 0.025 0.0009 3.8
10.9 0.026 0.0003 1.1 0.028 0.0023 8.3 0.029 0.0007 2.4
12.9 0.027 0.0005 1.7 0.030 0.0019 6.3 0.031 0.0009 2.8
16.9 0.028 0.0008 2.7 0.03 0.0028 9.2 0.0315 0.0003 1.0
18.3 0.029 0.0008 2.2 0.030 0.0032 8.5 0.032 0.0011 2.7
23.3 0.036 0.0015 11.5 0.037 0.0013 8.2 0.039 0.0009 5.4
25.3 0.040 0.0007 1.8 0.041 0.0013 3.2 0.042 0.0005 1.2
Table A.34: Sulfate Resistance of Mortar Made of HE Cement
Age
(Weeks)
HE HE -17µm HE -3µm
Average
Expansion
(%)
SD COV
(%)
Average
Expansion
(%)
SD COV
(%)
Average
Expansion
(%)
SD COV
(%)
0.0 0.000 --- --- 0.000 --- --- 0.000 --- ---
0.9 0.007 0.0009 12.8 0.010 0.0012 12.7 0.009 0.0008 8.9
2.0 0.007 0.0008 12.3 0.009 0.0011 12.1 0.008 0.0008 9.7
3.0 0.014 0.0015 10.8 0.016 0.0015 9.5 0.015 0.0004 2.7
4.7 0.015 0.0012 8.4 0.017 0.0017 10.0 0.016 0.0010 6.0
6.6 0.018 0.0012 6.9 0.020 0.0021 10.7 0.019 0.0006 3.2
8.0 0.021 0.0013 6.5 0.022 0.0024 10.8 0.021 0.0010 4.7
10.0 0.022 0.0014 6.4 0.024 0.0016 6.6 0.022 0.0012 5.5
12.0 0.021 0.0016 7.5 0.024 0.0017 7.0 0.022 0.0012 5.4
13.0 0.023 0.0015 6.7 0.025 0.0017 6.5 0.024 0.0010 4.3
17.9 0.028 0.0016 5.5 0.031 0.0021 6.8 0.029 0.0010 3.6
19.9 0.029 0.0014 4.8 0.031 0.0022 7.0 0.029 0.0010 3.6
199
Table A.35: Salt Scaling of Concrete
Mix ID Specimens # Mass Loss (kg/m2) after 50 Freeze-Thaw Cycles
GU
1 0.018
2 0.019
Avg. 0.019
GU-17µm
1 0.447
2 0.440
Avg. 0.444
GU-3µm
1 0.369
2 0.384
Avg. 0.376
HE
1 0.249
2 0.256
Avg. 0.253
HE-17µm
1 0.195
2 0.201
Avg. 0.198
HE-3µm
1 0.213
2 0.195
Avg. 0.204
200
Table A.36: Freeze-Thaw Resistance of Concrete
(75 mm × 75 mm × 285 mm Prisms- Tested in Chapter 4)
Mix ID Specimens # Length Change (%) Durability Factor (%)
GU
1 0.0115 98.3
2 0.0105 97.6
Avg. 0.0110 98.0
GU-17µm
1 0.0129 98.5
2 0.0135 97.6
Avg. 0.0132 98.1
GU-3µm
1 0.0119 98.1
2 0.0121 97.7
Avg. 0.0120 97.9
HE
1 0.0119 99.5
2 0.0121 98.5
Avg. 0.0120 99.0
HE-17µm
1 0.0165 97.5
2 0.0168 96.5
Avg. 0.0167 97.0
HE-3µm
1 0.0165 97.2
2 0.0168 96.9
Avg. 0.0167 97.1
201
Table A.37: Freeze-Thaw Resistance of Concrete
(50 mm × 50 mm × 285 mm Prisms- Tested in Chapter 5)
Mix ID
Steam
Curing
Temp.
Freeze-Thaw Durability Factor (%)
Sample # Average SD
COV
(%) 1 2 3
GU
55°C
97.0 98.0 99.0 98.0 1.0 1.0
GU-17µm 97.5 96.0 99.0 97.5 1.5 1.5
GU-3µm 98.2 98.0 99.6 98.6 0.9 0.9
HE 98.4 97.3 97.7 97.8 0.6 0.6
HE-17µm 96.3 95.8 97.1 96.4 0.7 0.7
HE-3µm 98.5 98.1 99.5 98.7 0.7 0.7
GUL 97.3 96.8 97.2 97.1 0.3 0.3
HS 98.5 98.0 98.1 98.2 0.3 0.3
HS-17µm 97.5 96.5 93.7 95.9 2.0 2.1
HS-3µm 97.3 95.1 96.2 96.2 1.1 1.1
GU
70°C
67.5 67.9 69.8 68.4 1.2 1.8
GU-17µm 79.2 82.4 79.3 80.3 1.8 2.3
GU-3µm 78.9 77.2 81.5 79.2 2.2 2.7
HE 81.4 79.1 82.8 81.1 1.9 2.3
HE-17µm 85.4 81.3 82.9 83.2 2.1 2.5
HE-3µm 87.8 82.3 84.0 84.7 2.8 3.3
GUL 81.4 83.2 81.7 82.1 1.0 1.2
HS 96.2 94.2 94.9 95.1 1.0 1.1
HS-17µm 93.9 91.1 94.9 93.3 2.0 2.1
HS-3µm 95.7 92.1 95.4 94.4 2.0 2.1
GU
82°C
57.4 53.8 56.2 55.8 1.8 3.3
GU-17µm 69.9 67.9 69.8 69.2 1.1 1.6
GU-3µm 75.5 70.1 71.3 72.3 2.8 3.9
HE 65.9 60.4 63.6 63.3 2.8 4.4
HE-17µm 72.6 68.6 74.5 71.9 3.0 4.2
HE-3µm 75.6 68.0 71.5 71.7 3.8 5.3
GUL 74.9 71.3 72.8 73.0 1.8 2.5
HS 94.5 90.4 91.4 92.1 2.1 2.3
HS-17µm 96.7 91.1 94.2 94.0 2.8 3.0
HS-3µm 98.2 93.0 98.0 96.4 2.9 3.1
202
A.7.5.1 Concrete Expansion
In this section, the expansion curves of concrete during the water immersion for 300 days
are presented. In addition, this section presents the raw data of concrete expansion up to
300 days.
A.7.5.1.1 Effect of Limestone Filler
In this section, the expansions of concrete mixes made with LF are compared to the
expansion of concrete mixes made without LF at different steam curing temperature, as
presented in Figures A.4 to A.9.
Figure A.4: Effect of 17µm LF on the Expansion of Concrete made of GU Cement
0.00
0.01
0.02
0.03
0.04
0.05
0 50 100 150 200 250 300
Exp
ansi
on (
%)
Age (Days)
GU-55°C GU-70°C GU-82°C
GU-17µm-55°C GU-17µm-70°C GU-17µm-82°C
203
Figure A.5: Effect of 3µm LF on the Expansion of Concrete made of GU Cement
Figure A.6: Effect of 17µm LF on the Expansion of Concrete made of HE Cement
0.00
0.01
0.02
0.03
0.04
0.05
0 50 100 150 200 250 300
Exp
ansi
on (
%)
Age (Days)
GU-55°C GU-70°C GU-82°C
GU-3µm-55°C GU-3µm-70°C GU-3µm-82°C
0.00
0.01
0.02
0.03
0.04
0.05
0 50 100 150 200 250 300
Exp
ansi
on (
%)
Age (Days)
HE-55°C HE-70°C HE-82°C
HE-17µm-55°C HE-17µm-70°C HE-17µm-82°C
204
Figure A.7: Effect of 3µm LF on the Expansion of Concrete made of HE Cement
Figure A.8: Effect of 17µm LF on the Expansion of Concrete made of HS Cement
0.00
0.01
0.02
0.03
0.04
0.05
0 50 100 150 200 250 300
Exp
ansi
on (
%)
Age (Days)
HE-55°C HE-70°C HE-82°C
HE-3µm-55°C HE-3µm-70°C HE-3µm-82°C
0.00
0.01
0.02
0.03
0.04
0.05
0 50 100 150 200 250 300
Exp
ansi
on (
%)
Age (Days)
HS-55°C HS-70°C HS-82°C
HS-17µm-55°C HS-17µm-70°C HS-17µm-82°C
205
Figure A.9: Effect of 3µm LF on the Expansion of Concrete made of HS Cement
A.7.5.1.2 Effect of Intergrinding Versus Blending of Limestone
In this section, the expansion of concrete mixture made of GUL cement is compared to the
expansion of concrete mixes made of GU cement blended with LF of 17µm and 3µm, as
presented in Figure A.10.
Figure A.10: Effect of Intergrinding and Blending LF on Concrete Expansion
0.00
0.01
0.02
0.03
0.04
0.05
0 50 100 150 200 250 300
Exp
ansi
on (
%)
Age (Days)
HS-55°C HS-70°C HS-82°C
HS-3µm-55°C HS-3µm-70°C HS-3µm-82°C
0.00
0.01
0.02
0.03
0.04
0.05
0 50 100 150 200 250 300
Exp
ansi
on (
%)
Age (Days)
GU-17µm-55°C GU-17µm-70°C GU-17µm-82°C
GU-3µm-55°C GU-3µm-70°C GU-3µm-82°C
GUL-55°C GUL-70°C GUL-82°C
206
Table A.38: Concrete Expansion of Mix GU
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
14 0.005 0.006 0.007 0.006 14 0.017 0.019 0.021 0.019 9 0.019 0.02 0.021 0.02
30 0.006 0.007 0.008 0.007 28 0.02 0.022 0.024 0.022 25 0.022 0.023 0.024 0.023
42 0.007 0.008 0.009 0.008 46 0.022 0.024 0.026 0.024 41 0.024 0.025 0.026 0.025
56 0.008 0.009 0.01 0.009 60 0.023 0.026 0.029 0.026 55 0.027 0.028 0.029 0.028
80 0.009 0.010 0.011 0.010 76 0.025 0.028 0.031 0.028 71 0.029 0.03 0.031 0.030
100 0.010 0.011 0.012 0.011 90 0.026 0.029 0.032 0.029 85 0.03 0.031 0.032 0.031
119 0.011 0.012 0.013 0.012 110 0.027 0.03 0.033 0.030 100 0.031 0.032 0.033 0.032
140 0.011 0.012 0.013 0.012 133 0.029 0.032 0.035 0.032 114 0.033 0.034 0.035 0.034
160 0.012 0.013 0.014 0.013 150 0.03 0.033 0.036 0.033 128 0.034 0.035 0.036 0.035
180 0.012 0.013 0.014 0.013 165 0.032 0.035 0.039 0.035 145 0.036 0.037 0.038 0.037
198 0.012 0.013 0.014 0.013 180 0.032 0.036 0.040 0.036 160 0.037 0.038 0.039 0.038
214 0.012 0.013 0.014 0.013 200 0.033 0.037 0.041 0.037 175 0.038 0.039 0.04 0.039
228 0.012 0.013 0.014 0.013 228 0.035 0.039 0.043 0.039 195 0.04 0.041 0.042 0.041
245 0.013 0.014 0.015 0.014 258 0.035 0.039 0.043 0.039 223 0.041 0.042 0.043 0.042
260 0.013 0.014 0.015 0.014 287 0.036 0.04 0.044 0.040 253 0.042 0.043 0.044 0.043
280 0.014 0.015 0.016 0.015 300 0.036 0.04 0.044 0.040 282 0.042 0.043 0.044 0.043
300 0.014 0.015 0.016 0.015 --- --- --- --- --- 300 0.043 0.044 0.045 0.044
207
Table A.39: Concrete Expansion of Mix GU-17µm
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
14 0.006 0.006 0.006 0.006 14 0.017 0.017 0.020 0.018 9 0.020 0.020 0.020 0.020
30 0.007 0.007 0.007 0.007 30 0.020 0.020 0.023 0.021 25 0.023 0.023 0.023 0.023
45 0.008 0.008 0.008 0.008 46 0.022 0.022 0.025 0.023 41 0.024 0.024 0.024 0.024
60 0.009 0.009 0.009 0.009 61 0.024 0.024 0.027 0.025 56 0.026 0.026 0.026 0.026
74 0.010 0.010 0.010 0.010 76 0.026 0.026 0.029 0.027 71 0.027 0.027 0.027 0.027
89 0.011 0.011 0.011 0.011 91 0.027 0.027 0.03 0.028 86 0.029 0.029 0.029 0.029
103 0.011 0.011 0.011 0.011 106 0.028 0.028 0.031 0.029 100 0.030 0.030 0.030 0.030
119 0.011 0.011 0.011 0.011 121 0.029 0.029 0.032 0.030 114 0.031 0.031 0.031 0.031
133 0.012 0.012 0.012 0.012 133 0.030 0.030 0.033 0.031 128 0.032 0.032 0.032 0.032
148 0.012 0.012 0.012 0.012 148 0.030 0.030 0.033 0.031 142 0.034 0.034 0.034 0.034
163 0.012 0.012 0.012 0.012 165 0.030 0.030 0.033 0.031 160 0.036 0.036 0.036 0.036
198 0.012 0.012 0.012 0.012 200 0.031 0.031 0.034 0.032 195 0.039 0.039 0.039 0.039
212 0.012 0.012 0.012 0.012 228 0.033 0.033 0.036 0.034 223 0.040 0.040 0.040 0.040
227 0.012 0.012 0.012 0.012 258 0.035 0.035 0.038 0.036 253 0.041 0.041 0.041 0.041
240 0.013 0.013 0.013 0.013 287 0.036 0.036 0.039 0.037 282 0.042 0.042 0.042 0.042
254 0.013 0.013 0.013 0.013 300 0.036 0.036 0.039 0.037 300 0.042 0.042 0.042 0.042
280 0.013 0.013 0.013 0.013 --- --- --- --- --- --- --- --- --- ---
300 0.014 0.014 0.014 0.014 --- --- --- --- --- --- --- --- --- ---
208
Table A.40: Concrete Expansion of Mix GU-3µm
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
14 0.008 0.008 0.005 0.007 14 0.019 0.022 0.016 0.019 9 0.018 0.015 0.018 0.017
30 0.010 0.009 0.006 0.008 28 0.022 0.025 0.019 0.022 24 0.021 0.018 0.021 0.020
45 0.010 0.009 0.006 0.008 46 0.023 0.026 0.020 0.023 41 0.023 0.019 0.024 0.022
59 0.011 0.010 0.006 0.009 60 0.024 0.028 0.020 0.024 55 0.024 0.020 0.025 0.023
74 0.011 0.010 0.006 0.009 76 0.025 0.029 0.021 0.025 71 0.025 0.021 0.026 0.024
88 0.011 0.010 0.006 0.009 90 0.026 0.03 0.022 0.026 85 0.027 0.023 0.028 0.026
119 0.013 0.012 0.008 0.011 118 0.028 0.032 0.024 0.028 114 0.030 0.026 0.031 0.029
134 0.013 0.012 0.008 0.011 133 0.029 0.033 0.025 0.029 128 0.030 0.026 0.031 0.029
148 0.014 0.013 0.008 0.012 147 0.030 0.035 0.026 0.030 143 0.033 0.027 0.033 0.031
163 0.014 0.013 0.008 0.012 165 0.031 0.036 0.026 0.031 160 0.035 0.029 0.035 0.033
179 0.014 0.013 0.008 0.012 180 0.032 0.037 0.027 0.032 174 0.037 0.031 0.037 0.035
198 0.014 0.013 0.008 0.012 200 0.033 0.038 0.028 0.033 195 0.038 0.032 0.039 0.036
212 0.016 0.014 0.009 0.013 228 0.034 0.039 0.029 0.034 223 0.039 0.033 0.040 0.037
226 0.016 0.014 0.009 0.013 258 0.036 0.041 0.031 0.036 253 0.040 0.033 0.041 0.038
240 0.016 0.014 0.009 0.013 280 0.037 0.043 0.031 0.037 280 0.041 0.034 0.042 0.039
254 0.016 0.014 0.009 0.013 300 0.037 0.043 0.031 0.037 300 0.041 0.034 0.042 0.039
280 0.017 0.015 0.010 0.014 --- --- --- --- --- --- --- --- --- ---
300 0.017 0.015 0.010 0.014 --- --- --- --- --- --- --- --- --- ---
209
Table A.41: Concrete Expansion of Mix HE
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
14 0.007 0.006 0.008 0.007 14 0.019 0.018 0.015 0.017 8 0.014 0.015 0.016 0.015
30 0.008 0.007 0.009 0.008 30 0.024 0.023 0.019 0.022 25 0.021 0.022 0.023 0.022
45 0.009 0.008 0.010 0.009 46 0.025 0.024 0.020 0.023 40 0.022 0.023 0.024 0.023
60 0.009 0.008 0.010 0.009 60 0.026 0.025 0.021 0.024 55 0.024 0.025 0.026 0.025
75 0.010 0.009 0.011 0.010 76 0.027 0.026 0.022 0.025 70 0.026 0.027 0.028 0.027
100 0.010 0.009 0.011 0.010 90 0.028 0.027 0.023 0.026 95 0.028 0.029 0.030 0.029
119 0.011 0.01 0.012 0.011 114 0.029 0.028 0.023 0.027 100 0.029 0.03 0.032 0.030
135 0.012 0.011 0.013 0.012 133 0.031 0.029 0.024 0.028 114 0.030 0.031 0.033 0.031
150 0.013 0.012 0.014 0.013 150 0.032 0.03 0.025 0.029 127 0.030 0.031 0.033 0.031
175 0.013 0.012 0.014 0.013 165 0.034 0.032 0.027 0.031 142 0.031 0.032 0.034 0.032
198 0.013 0.012 0.014 0.013 180 0.034 0.032 0.027 0.031 159 0.033 0.034 0.036 0.034
214 0.013 0.012 0.014 0.013 200 0.034 0.032 0.027 0.031 180 0.034 0.035 0.037 0.035
228 0.014 0.013 0.015 0.014 214 0.035 0.033 0.028 0.032 208 0.035 0.036 0.038 0.036
245 0.014 0.013 0.015 0.014 228 0.036 0.034 0.029 0.033 222 0.036 0.037 0.039 0.037
260 0.014 0.013 0.015 0.014 242 0.037 0.035 0.030 0.034 236 0.036 0.037 0.039 0.037
300 0.015 0.014 0.016 0.015 258 0.038 0.036 0.030 0.035 252 0.036 0.038 0.040 0.038
--- --- --- --- --- 287 0.039 0.037 0.031 0.036 281 0.037 0.039 0.041 0.039
--- --- --- --- --- 300 0.039 0.037 0.031 0.036 300 0.037 0.039 0.041 0.039
210
Table A.42: Concrete Expansion of Mix HE-17µm
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
14 0.007 0.007 0.007 0.007 13 0.018 0.017 0.013 0.016 8 0.014 0.012 0.016 0.014
30 0.008 0.007 0.009 0.008 27 0.021 0.02 0.016 0.019 23 0.019 0.017 0.021 0.019
44 0.008 0.007 0.009 0.008 45 0.022 0.021 0.017 0.020 40 0.02 0.018 0.022 0.020
60 0.009 0.008 0.010 0.009 60 0.023 0.022 0.018 0.021 55 0.022 0.020 0.024 0.022
74 0.009 0.008 0.010 0.009 75 0.024 0.023 0.019 0.022 70 0.023 0.021 0.025 0.023
88 0.009 0.008 0.010 0.009 90 0.025 0.024 0.020 0.023 85 0.024 0.022 0.026 0.024
102 0.009 0.008 0.010 0.009 104 0.025 0.024 0.020 0.023 99 0.025 0.023 0.027 0.025
119 0.010 0.009 0.011 0.010 118 0.026 0.025 0.021 0.024 113 0.026 0.024 0.028 0.026
134 0.010 0.009 0.011 0.010 132 0.028 0.026 0.022 0.025 127 0.027 0.025 0.029 0.027
148 0.010 0.009 0.011 0.010 146 0.029 0.027 0.022 0.026 142 0.028 0.026 0.030 0.028
164 0.010 0.009 0.011 0.010 164 0.030 0.028 0.023 0.027 159 0.029 0.027 0.031 0.029
179 0.011 0.010 0.012 0.011 178 0.031 0.029 0.024 0.028 174 0.029 0.027 0.031 0.029
198 0.011 0.010 0.012 0.011 192 0.033 0.031 0.026 0.030 194 0.030 0.028 0.032 0.030
215 0.012 0.011 0.013 0.012 227 0.034 0.032 0.027 0.031 222 0.031 0.029 0.033 0.031
230 0.012 0.011 0.013 0.012 257 0.035 0.033 0.028 0.032 252 0.031 0.030 0.034 0.032
255 0.013 0.012 0.014 0.013 279 0.036 0.033 0.028 0.032 270 0.032 0.030 0.034 0.032
280 0.013 0.012 0.014 0.013 300 0.036 0.034 0.029 0.033 300 0.032 0.030 0.034 0.032
300 0.013 0.012 0.014 0.013 --- --- --- --- --- --- --- --- --- ---
211
Table A.43: Concrete Expansion of Mix HE-3µm
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0.000 0 0 0 0 0.000 0 0 0 0 0.000
14 0.009 0.008 0.005 0.007 13 0.020 0.015 0.016 0.017 8 0.013 0.015 0.017 0.015
30 0.010 0.009 0.006 0.008 27 0.022 0.017 0.018 0.019 23 0.016 0.019 0.022 0.019
44 0.010 0.009 0.006 0.008 45 0.023 0.018 0.019 0.020 40 0.017 0.020 0.023 0.020
60 0.011 0.010 0.006 0.009 60 0.025 0.019 0.020 0.021 55 0.019 0.022 0.025 0.022
74 0.011 0.010 0.006 0.009 75 0.026 0.020 0.021 0.022 70 0.021 0.024 0.027 0.024
88 0.011 0.010 0.006 0.009 90 0.027 0.021 0.022 0.023 85 0.022 0.025 0.028 0.025
102 0.012 0.011 0.007 0.010 104 0.028 0.022 0.023 0.024 99 0.023 0.026 0.029 0.026
119 0.012 0.011 0.007 0.010 118 0.029 0.023 0.024 0.025 113 0.024 0.027 0.030 0.027
134 0.012 0.011 0.007 0.010 132 0.030 0.023 0.024 0.026 127 0.025 0.028 0.031 0.028
148 0.012 0.011 0.007 0.010 146 0.032 0.025 0.026 0.028 142 0.026 0.029 0.032 0.029
164 0.012 0.011 0.007 0.010 164 0.033 0.026 0.027 0.029 159 0.027 0.030 0.033 0.030
179 0.013 0.012 0.008 0.011 178 0.035 0.027 0.028 0.030 174 0.028 0.031 0.034 0.031
198 0.013 0.012 0.008 0.011 192 0.036 0.028 0.029 0.031 194 0.028 0.032 0.036 0.032
215 0.014 0.013 0.009 0.012 227 0.036 0.028 0.029 0.031 222 0.029 0.033 0.037 0.033
230 0.014 0.013 0.009 0.012 257 0.037 0.029 0.030 0.032 252 0.030 0.034 0.038 0.034
245 0.015 0.013 0.010 0.013 280 0.037 0.029 0.030 0.032 280 0.031 0.034 0.038 0.034
266 0.015 0.013 0.010 0.013 300 0.037 0.030 0.031 0.033 300 0.031 0.035 0.038 0.035
300 0.016 0.014 0.011 0.013 --- --- --- --- --- --- --- --- --- ---
212
Table A.44: Concrete Expansion of Mix GUL
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0 0 0 0.000 0 0 0 0 0 0 0
22 0.008 0.007 0.006 0.007 21 0.007 0.012 0.008 0.009 20 0.012 0.014 0.010 0.012
36 0.009 0.008 0.007 0.008 35 0.012 0.017 0.013 0.014 34 0.016 0.018 0.013 0.016
52 0.010 0.009 0.008 0.009 51 0.015 0.022 0.017 0.018 52 0.02 0.023 0.017 0.020
79 0.009 0.008 0.007 0.008 78 0.019 0.026 0.021 0.022 77 0.025 0.028 0.022 0.025
111 0.011 0.010 0.009 0.010 110 0.021 0.028 0.023 0.024 109 0.028 0.032 0.025 0.028
146 0.013 0.012 0.011 0.012 145 0.023 0.030 0.025 0.026 144 0.029 0.033 0.026 0.029
174 0.014 0.013 0.012 0.013 173 0.024 0.031 0.026 0.027 172 0.030 0.034 0.027 0.030
204 0.016 0.015 0.014 0.015 203 0.025 0.034 0.028 0.029 202 0.030 0.035 0.028 0.031
233 0.016 0.015 0.014 0.015 232 0.025 0.034 0.028 0.029 231 0.032 0.037 0.030 0.033
280 0.017 0.016 0.015 0.016 250 0.026 0.036 0.030 0.031 280 0.033 0.038 0.031 0.034
300 0.017 0.016 0.015 0.016 270 0.027 0.036 0.030 0.031 300 0.033 0.038 0.031 0.034
--- --- --- --- --- 300 0.027 0.036 0.030 0.031 --- --- --- --- ---
213
Table A.45: Concrete Expansion of Mix HS
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0 0 0 0.000 0 0 0 0 0 0 0
22 0.008 0.012 0.010 0.01 21 0.006 0.006 0.009 0.007 20 0.006 0.005 0.004 0.005
37 0.011 0.015 0.013 0.013 38 0.009 0.009 0.012 0.010 37 0.011 0.01 0.009 0.010
79 0.013 0.018 0.015 0.015 78 0.009 0.010 0.014 0.011 77 0.016 0.014 0.012 0.014
111 0.015 0.021 0.018 0.018 110 0.010 0.011 0.015 0.012 109 0.017 0.015 0.013 0.015
146 0.016 0.022 0.019 0.019 145 0.011 0.012 0.016 0.013 144 0.018 0.016 0.014 0.016
174 0.016 0.022 0.019 0.019 173 0.012 0.013 0.017 0.014 172 0.02 0.018 0.016 0.018
204 0.016 0.022 0.019 0.019 203 0.013 0.014 0.018 0.015 202 0.02 0.018 0.016 0.018
233 0.017 0.023 0.020 0.020 232 0.013 0.014 0.018 0.015 231 0.021 0.019 0.017 0.019
276 0.017 0.024 0.021 0.021 275 0.015 0.015 0.020 0.017 274 0.022 0.021 0.019 0.021
300 0.018 0.024 0.021 0.021 300 0.015 0.015 0.020 0.017 300 0.023 0.021 0.019 0.021
214
Table A.46: Concrete Expansion of Mix HS-17µm
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
22 0.008 0.007 0.012 0.009 22 0.009 0.008 0.006 0.008 22 0.013 0.009 0.011 0.011
36 0.010 0.009 0.014 0.011 37 0.012 0.010 0.008 0.010 37 0.014 0.010 0.012 0.012
79 0.011 0.010 0.015 0.012 79 0.013 0.011 0.009 0.011 79 0.015 0.011 0.013 0.013
111 0.011 0.010 0.015 0.012 111 0.014 0.012 0.010 0.012 111 0.016 0.012 0.014 0.014
146 0.011 0.011 0.017 0.013 146 0.016 0.015 0.011 0.014 146 0.017 0.013 0.015 0.015
174 0.012 0.012 0.018 0.014 174 0.017 0.016 0.012 0.015 174 0.019 0.015 0.017 0.017
204 0.013 0.013 0.019 0.015 204 0.018 0.017 0.013 0.016 204 0.020 0.016 0.018 0.018
233 0.014 0.014 0.019 0.016 233 0.020 0.019 0.015 0.018 233 0.020 0.017 0.019 0.019
278 0.014 0.015 0.019 0.016 278 0.021 0.019 0.015 0.018 280 0.021 0.017 0.019 0.019
300 0.014 0.015 0.019 0.016 300 0.021 0.019 0.015 0.018 300 0.021 0.017 0.019 0.019
215
Table A.47: Concrete Expansion of Mix HS-3µm
Steam Curing Temperature
55°C 70°C 82°C
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
Age
(Days) 1 2 3
Average
Expansion
(%)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
22 0.012 0.011 0.007 0.010 21 0.008 0.008 0.011 0.009 20 0.010 0.010 0.013 0.011
38 0.014 0.013 0.009 0.012 36 0.010 0.010 0.013 0.011 36 0.011 0.011 0.014 0.012
79 0.014 0.013 0.009 0.012 78 0.010 0.010 0.013 0.011 77 0.013 0.013 0.016 0.014
111 0.015 0.014 0.013 0.014 110 0.010 0.010 0.013 0.011 109 0.014 0.014 0.018 0.015
146 0.015 0.014 0.009 0.013 145 0.011 0.011 0.014 0.012 144 0.014 0.015 0.019 0.016
174 0.017 0.016 0.012 0.015 173 0.013 0.013 0.016 0.014 172 0.015 0.016 0.020 0.017
204 0.019 0.018 0.012 0.016 203 0.014 0.015 0.019 0.016 202 0.017 0.018 0.022 0.019
233 0.020 0.019 0.013 0.017 232 0.014 0.015 0.019 0.016 231 0.018 0.019 0.023 0.020
276 0.02 0.019 0.015 0.018 275 0.016 0.017 0.021 0.018 274 0.019 0.020 0.024 0.021
300 0.021 0.019 0.014 0.018 300 0.016 0.017 0.021 0.018 300 0.020 0.020 0.023 0.021
216
A.7.6 Scanning Electron Microscopy
In this section, flatbed scanner images of thin-sections used in this thesis are presented
which shows the locations of SEM images. Furthermore, additional SEM images are
presented.
Figure A.11: Flatbed Scanner Image of Thin-Section Sowing Locations of SEM Images
of Mix GU-17µm-82°C
217
Figure A.12: Flatbed Scanner Image of Thin-Section Sowing Locations of SEM Images
of Mix GU-17µm-55°C
Fig. 5.17 a
Fig. A.17 a
Fig. A.17 b
218
Figure A.13: Flatbed Scanner Image of Thin-Section Sowing Locations of SEM Images
of Mix GU-17µm-70°C
Fig. 5.17 b
Fig. A.19 a
Fig. A.19 b
219
Figure A.14: Flatbed Scanner Image of Thin-Section Sowing Locations of SEM Images
of Mix GU-70°C
Fig. 5.18a
Fig. A.18a
Fig. A.18b
220
Figure A.15: Flatbed Scanner Image of Thin-Section Sowing Locations of SEM Images
of Mix GU-82°C
Fig. 5.18b
Fig. A.20
221
Figure A.16: Flatbed Scanner Image of Thin-Section Sowing Locations of SEM Images
of Mix HS-17µm-82°C
Fig. 5.19
Fig. A.24
Fig. A.23
222
Figure A.17: SEM (Backscattered Electron) Images of Concrete Mixture GU-17µm-55°C
(a)
(b)
223
Figure A.18: SEM (Backscattered Electron) Images of Concrete Mixture GU-70°C
Showing Microcracks (Circles)
(a)
(b)
224
Figure A.19: SEM (Backscattered Electron) Images of Concrete Mixture GU-17µm-70°C
(a)
(b)
225
Figure A.20: SEM (Backscattered Electron) Images of Concrete Mixture GU-82°C
Showing Narrow Gaps Surrounding the Sand Particles, Ettringite Deposits in the
Interfacial Transition Zone (squares) and Microcracks (circles)
226
Figure A.21: SEM (Backscattered Electron) Images of Concrete (GU-17µm-82°C)
Showing Narrow Empty Gaps (Circles) Surrounding Sand Particles and Ettringite
Deposits (Squares) Found in the Interfacial Transition Zone
227
Figure A.22: SEM (Backscattered Electron) Images of Concrete Mixture GU-17µm-82°C
Showing Showing Narrow Empty Gaps Surrounding Sand Particles
228
Figure A.23: SEM (Backscattered Electron) Images of Concrete Mixture HS-17µm-82°C
Figure A.24: SEM (Backscattered Electron) Images of Concrete Mixture HS-17µm-82°C
229
Appendix B Publication Plan
The following are list of journal papers created from the results and findings of this thesis:
Paper I (based on Chapter 2)
Aqel, M., and Panesar, D. Physical and Chemical Effects of Limestone Filler on Steam
Cured Cement Paste, Mortar and Concrete. Submitted to Cement and Concrete Research
Journal on May 2015.
Paper II (presented in Chapter 3)
Aqel, M., and Panesar, D. (2016). Hydration Kinetics and Compressive Strength of Steam-
Cured Cement Pastes and Mortars Containing Limestone Filler. Construction and Building
Materials, Vol. 113, 359-368.
Paper III (presented in Chapter 4)
Aqel, M., Panesar, D., Rhead, D., and Schell, H. Effect of Cement and Limestone Particle
Size on the Durability of Steam Cured Self-Consolidating Concrete. Submitted to Cement
and Concrete Composites Journal on May 2016.
Paper IV (presented in Chapter 5)
Delayed Ettringite Formation in Self-Consolidating Concrete Containing Limestone Filler.
To be submitted on August 2016.
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