STST‐‐13:Fiber13:Fiber‐‐Reinforced Concrete Reinforced Concrete STST 13:Fiber13:Fiber Reinforced Concrete Reinforced Concrete Incorporating Recycled Concrete FinesIncorporating Recycled Concrete Fines

STST‐‐14: Green Concrete Incorporating 14: Green Concrete Incorporating 4 p g4 p gLocal Waste MaterialLocal Waste Material

Recycled Concrete Fines & Engineered CementitiousgComposities

Enhanced greenness of ECC

Effect of RCF on ECC mechanical properties

ff fEffect of RCF on ECC  on mirco structure aspect using Micromechanics Model

• Importance of the reuse construction and d li i   demolition  waste

• Property of RCFHigh water absorption 

• A class of ultra ductile fiber reinforced cementitiouscomposites

Normal ECC Composites

Water, Cement, Fiber, S d Additi  Sand, Additives 

Mitaka Dam near Hiroshima

N l C t Engineered CementitiousNormal Concrete Engineered CementitiousComposities (ECC)

Taken from: https://www.youtube.com/watch?v=tsGfCCY4_Gw

Hi h E i t l b dHi h E i t l b dHigh Environmental burdenHigh Environmental burdenVi  C  Li  D l   f G  E i d C iVictor C. Li, Development of Green Engineered CementitousComposites For Sustainable Infrasture Systems

Due to high cement content and introduction of PVA 

fibfibers

S l i f CS l i f CSupplementation of Cement Supplementation of Cement 

C3S + H2O  C‐S‐H + CHCH + SiOSiO22 C‐S‐H

Present in Ground Granulated Blast Furnace Slag (GGBS)

GGBS content

Compressive Strength

Ductility 

  % I D  10 – 30% Increase Decrease 

55 – 59 % Increase Decrease 

> 69% Decrease  Increase 

Supplementation of Supplementation of AAAAggregates ggregates 

Lack of aggregatesLack of aggregates

Normal ECC Composites

RCF‐ECC Composites

Water, Cement, Fiber, Sand, Additives 

Water, Cement, Slag, Fiber, Recycled Concrete Fines(RCF),Additi  Additives 

S lfS lf i C ti C tSelfSelf‐‐sensing Concrete sensing Concrete 

Obj tiObj tiObjective Objective 

Enhanced the Enhanced the GreenGreenness of ECCness of ECC

Investigate the effect of RCF on GGBS‐ECC of its mechanical propertiesp p

Self‐sensing measurement setup for future research

SSScope Scope Compressive Strength Flexural Strength & Deflection

Self‐sensing measurement setup stability 

Mix DesignMix DesignMix DesignMix DesignNatural aggregates 

RCFCement 

Cement + GGBS

RCF  PVA 

RCFCement + GGBS

Group 1 Cement Slag Water/B1 RCF/Bsize/mm fiber2

SP3/ B

RS‐1 1 0.8 0.25 0 0~0.6 2% 0.5%

RS‐2 1 0.8 0.25 0.2 0~0.6 2% 0.8%

RS‐3 1 0.8 0.25 0.5 0~0.6 2% 0.8%

RS‐7 1 0.8 0.25 0.2 0~0.3 2% 0.8%7 5 3

RS‐8 1 0.8 0.25 0.2 0~1.18 2% 0.8%

RS‐9 1 0.8 0.25 0.2 0~2.36 2% 0.8%

1.B=cement+slag; 2. Percentage by volume; 3.SP=superplasticizer.

Mi D iMi D iMix DesignMix Design

Group 1 RCF Content

Group 2 RCF size/µm

RS‐1 0 RS‐7 0‐300

RS‐2 0.2

RS‐3 0.5

RS‐2 0‐600

RS‐8 0‐1180

RS‐9 0‐2360

C b C i T tC b C i T t

Experimental Procedures

Cube Compression TestCube Compression Test

Load Cell

Concrete Specimen

Cylinder Compression TestCylinder Compression TestExperimental Procedures

Cylinder Compression TestCylinder Compression TestLoad Cell

10mm LVDT

Concrete Specimenp

Magnetic Stand

4 i t B di T t4 i t B di T t

Experimental Procedures

Loading Pins

4 point Bending Test4 point Bending Testoad g s

Concrete Specimen

Supporting Pins

S lf S i M tS lf S i M t

Experimental Procedures

Self Sensing Measurement Self Sensing Measurement 

Pl i  ShPlastic Sheet

Copper Wire

S lf S i M tS lf S i M t

Experimental Procedures

Self Sensing Measurement Self Sensing Measurement AC current source

Digital Multimeter

D itD itDensityDensity(g/cm3) (g/cm3) 

The degree of compactness of a substance

CompressiveCompressiveCompressive Compressive Strength Strength (28 days)(28 days)(28 days)(28 days)The resistance of the concrete to break under compression

CompressiveCompressiveCompressive Compressive Strength Strength (90 days)(90 days)(90 days)(90 days)The resistance of the concrete to break under compression

CompressiveCompressive

Group 2- RCF sizes

Compressive Compressive Strength Strength ComparisonComparisonComparisonComparison

Fl l S h C l l iFl l S h C l l iFlexural Strength Calculation Flexural Strength Calculation 

Flexural Strength V Deflection Flexural Strength V Deflection Group 1- RCF content

(28 days)(28 days)

FlexuralFlexural

Group 1- RCF content

Flexural Flexural Strength Strength & & DeflectionDeflectionDeflection Deflection (28 days)(28 days)Flexural strength is a 

l' b lmaterial's ability to resist deformation under load

Flexural Strength V Deflection Flexural Strength V Deflection Group 2- RCF sizes

(28 days)(28 days)

FlexuralFlexural

Group 2- RCF sizes

Flexural Flexural Strength Strength & & DeflectionDeflectionDeflection Deflection (28 days)(28 days)

Flexural Strength V Deflection Flexural Strength V Deflection Group 2- RCF sizes

(90 days)(90 days)

FlexuralFlexural

Group 2- RCF sizes

Flexural Flexural Strength Strength & & DeflectionDeflectionDeflection Deflection (90days)(90days)

FlexuralFlexural

Group 2- RCF sizes

Flexural Flexural Strength Strength ComparisonComparisonComparison Comparison (90days)(90days)

Group 2- RCF sizes

Deflection Deflection ComparisonComparisonComparisonComparison(90days)(90days)

SelfSelf‐‐sensing sensing MeasurementMeasurementMeasurementMeasurementChange in resistivity under compression 

1 2 3

1. Compressive Strength drop as RCF content increase2. A slight drop then rise in compressive strength as 

RCF  i  iRCF size increase

D i    f  i i  RCF    d  i  3. Decreasing σ for increasing RCF content and size with RS9 as exceptional

4 Decreasing deflection for increasing RCF and size4. Decreasing deflection for increasing RCF and size

Future studies on RS 9 as it display a higher flexural strength which is contract to the gtrend in flexural strength and deflection.

To develop a more accurate tensile behavior of the ECC  uniaxial tensile test  which pull of the ECC, uniaxial tensile test  which pull the specimen could be used.

C it  T il  Composite Tensile Ductility

Steady‐state crack analysis

Fiber Bridging Property (σ‐δ) across cracks

crack analysis

Micromechanics

Fiber, Matrix, Interface

Aim: Achieve the tensile strain hardening behaviorAim: Achieve the tensile strain‐hardening behavior

Energy Criteria:Energy Criteria:

σ0

Jb

σss

JtipCrack Tip  l

δss δ0

tipCrack Tip Toughness

Complementary Energy 

ss 0

Chemical Bond Strength

Constant friction bond strengthg

Slip Hardening Coefficient

Complementary Energy

Fracture Toughness

Li, V C., On Engineered Cementitious Composites (ECC) A review of the Material and Its Applications. Journal of Advanced Concrete Technology Vol 1  No 3  2003  pp215‐230 Technology Vol 1, No 3, 2003, pp215‐230 

Determine the interfacial properties and matrix toughness properties

Evaluation of the effects of RCF content and particle size on ECC tensile properties based on micromechanics model 

Single Fiber Pullout Test

Matrix Toughness Test

Particle Size: 0 0 6mmParticle Size: 0‐0.6mm

Actuator

Aluminum Plate

Specimen Mount

10 N Load Cell

X‐Y table

Free Length Specimen

Thickness=1 1mmThickness 1.1mm

A t tActuator

Clip Gauge Wedging Device

Steel loading  d i   i h  ll  

Clip Gauge Wedging Device

device with roller bearings

Specimen

RCF SizeRCF Size(0(0‐‐0.60.6μμm)m)

GdGd(J/m^2)(J/m^2)

ƮƮ((MpaMpa))

ββJbJb’’

(J/m^2)(J/m^2)

RS1 RCF/B=0 1.0162 2.4300 0.5196 10.14

RS2RCF/B=0.2 0.5475 2.4041 0.2504 11.25

RS3RCF/B=0.5 0.2623 2.6177 0.1956 11.47

RCF RCF ContentContent(0.2)(0.2)

GdGd(J/m^2)(J/m^2)

ƮƮ((MpaMpa))

ββJbJb’ ’ 

(J/m^2)(J/m^2)

RS7RS7(0‐0.3mm) 1.4241 2.1450 0.4582 9.75

RS2(0‐0.6mm) 0.5475 2.4041 0.2504 11.25

RS80 5697 1 8858 0 1760 12 72(0‐1.18mm) 0.5697 1.8858 0.1760 12.72

RS9(0‐2.36mm) 0.2438 2.1604 0.3180 13.37

Graph of Km Graph of Km vsvs RCF ContentRCF Content

Li, V C., On Engineered Cementitious Composites (ECC) A review of the Material and Its Applications , 2003

To evaluate the effect on the RCF content

To evaluate the effect on the RCF size

1 Jtip and Jb’ increases with both RCF 1. Jtip and Jb  increases with both RCF content and size.

2 Jb’/Jtip shows both decreasing trend for 2. Jb /Jtip shows both decreasing trend for increasing RCF content and size which is not desirable to achieve the strain‐not desirable to achieve the strainhardening behavior.

3 RCF is not desirable material to replace     3. RCF is not desirable material to replace     sand in the ECC

1. To determine a more accurate experimental work the Young modules for every mix shouldwork, the Young modules for every mix should be determined as the RCF-ECC is different from the conventional concrete.

2. Further research could be done to determine the optimal amount of RCF content and size that achieve the maximum strain hardening effect which is beneficial to the constructioneffect which is beneficial to the construction industry.