Ultimate Strength of Steel Fabric Reinforced Concrete ... 11 I 01/115201-3838 IJCEE-IJENS.pdf ·...

International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol: 11 No: 01 42

115201-3838 IJCEE-IJENS © February 2011 IJENS I J E N S

Ultimate Strength of Steel Fabric Reinforced

Concrete Short Wall Panel Using Crushed

Concrete Waste Aggregate (CCwA)

Mohd Suhelmiey Sobri1, Siti Hawa Hamzah

2, Ahmad Ruslan Mohd. Ridzuan

3

M.Sc Student1, Professor

2, Associate Professor

3

Institute for Infrastructure Engineering and Sustainable Management (IIESM)

Faculty of Civil Engineering, Universiti Teknologi MARA, 40450 Shah Alam Malaysia

Email: [email protected], [email protected]

2, [email protected]

3.

Abstract-- Green Building Index (GBI) launched on 21st March

2009 formalised the commitment of the Malaysian Government towards sustainable issues. In line with this, the use of crushed

concrete waste aggregate (CCwA) as a coarse aggregate is seen as

a potential replacement in concrete mix production. This

research has been conducted to study the behaviour of the steel

fabric reinforced concrete short wall panel as IBS component incorporating CCwA replacing the Natural Aggregate (NA). Ten

(10) samples were prepared using Grade 30 normal Ordinary

Portland Cement (OPC) concrete with water cement ratio of

0.55, measuring 75 mm x 1000 mm x 500

(Thickness:Length:Height). The aspect ratio (H/L) and slenderness ratio (H/t) of the wall panel are 0.5 and 6.67

respectively. Two (2) wall panels prepared with single layer and

two (2) wall panels with double layer of steel fabric using CCwA

as a coarse aggregate, another two (2) wall panel samples with

single layer and double layer by using Natural Aggregate (NA) as control samples. Four (4) samples were tested on fatigue load test

to determine the ultimate cycles before wall panel failure. The

short wall panel was subjected to compressive axial and fatigue

load with pin-fix end conditions at upper and lower ends until

failure. The experimental result shows that all ten (10) wall panels failed in compression shear with crushing at upper and

lower ends edge of the wall panel. The average ultimate load for

single and double layer steel fabric reinforced concrete short wall

panel is 1349 kN and 1643 kN respectively. A single curvature

crushing crack pattern is dominant for all samples with average maximum lateral displacement for single and double layer of

steel fabric reinforced concrete short wall panel is 2.9 mm and

3.8 mm respectively, occurred at 375 mm (0.7H) wall height. The

structural behaviour of reinforced concrete short wall panel

using CCwA as a coarse aggregate is similar with wall panel using NA in terms of structural strength capacity, displacement

profile, and mode of failure. The percentage different between

the usage of CCwA and NA in wall panel in term of ultimate

strength decreased by 5.5 % and 6.6 % for single layer and

double layer of wall panel respectively. The finding confirmed the performance of CCwA is as good as NA. This helps to reduce

unnecessary wastages and also prevent depletion of natural

resources. CCwA wall panels also address one of the six key

criteria of GBI which is Material and Resources. “Malaysia is

Green”.

Index Term-- Crushed concrete waste aggregate (CCwA),

reinforced concrete wall panel, steel fabric, crushing failure

1.0 INTRODUCTION

The growth of construction activities in Malaysia is

very fast and more complicated than ever before. The

expertise such as engineer, architect, designer, developer and

authorities involved in this field should seek the better

solution to face this issue and challenges in changing the

construction industry environment. On October 2003, the

government of Malaysia introduced the master plan to

transform Malaysian Construction known as “Industrialised

Building System (IBS) Roadmap 2003-2010” [10]. In this

transformation, the government stated a 5-M Strategy which is

Manpower, Material – component – Machines, Management –

process – method, Monetary and Marketing. Industrialised

Building System (IBS) is define as a construction system in

which component are manufactured in a factory, on or off site,

positioned and assembled into structure with minimal

additional site work [10]. The government launched a pilot

project by using IBS component on high rise building with 6

block of 17-storey each at Jalan Pekeliling (Figure 1.1) in

early 1960s to speed

up the time in building affordable and quality houses. The

Treasury of Malaysia announced in its 2005 budget that, the

contractor should use IBS components exceeding 50 percent

in Government funded project. On 31st

Oct 2008 the Treasury

stated that, the contractor should get the 70 % IBS Score for

all projects, before the contractor qualify for full exemption on

levy imposed by CIDB [13]. In other words, the government

and CIDB have significant reason to promote the IBS in

construction industry because of IBS improves productivity

rate, lowers construction cost, and produces affordable

housing cost [4]. Since using the IBS System in Malaysia is

expanding fast for high rise building, the production of precast

concrete element product such as precast beams, columns,

slabs, walls, staircases, parapets and drains increased

drastically, as well as other relatively new precast components

for toilets, pile caps, facades, lift shaft and refuse chamber.

Presently, most structural wall panel component system are

made of precast component since these systems provide

quality construction, save cost, create s afer and cleaner

working environment as

mailto:[email protected]

mailto:[email protected]



Fig. 1.1. Application of IBS in Malaysia for Flat Pekeliling built in January 1969

well as reduce the dependence of foreign workers [13]. In

conventional building construction method, wall is less used

as load-bearing wall element because all loadings from top of

the building is directly transfer through the column and to the

foundation. Steel fabric reinforced concrete wall panel is a

commonly used load bearing wall, used in the construction of

the high rise buildings in Malaysia. In this method, normal bar

is substituted by steel fabric as this type of reinforcement

produce fast installation and cost effective when compared to

conventional wall. The conventional infill wall using bricks

and mortar in framed construction require longer time and

man-power to install. The cost of the construction furthermore

increases when compared to the usage of the precast wall

panel. Nowadays, the Malaysian Government emphasizes on

green constructions, therefore by applying IBS in construction

industry, it realizes its intention towards green technology. As

we know, the construction industry is a major consumer of

non-renewable resources, a massive producer of construction

waste and contributed to release of CO2 from transportation

trips. Apart from that, the weight factor from large precast

structural component poses big problem on the transportability

of the component to the construction site [4]. As such the

reinforced concrete short wall panel is envisaged as a way to

solve this problem, where it replaces the huge precast concrete

wall panel. Reinforced concrete short wall panel is easier to be

handled manually, cast on site, requires less crane usage

during installation and as such the contractor can control the

CO2 emission from transportation trips. The green technology

promotes green building initiative which is based on six (6)

main criteria of Energy Efficiency, Indoor Environment

Quality, Sustainable Site Planning & Management, Material

Resources, Water Efficiency, and Innovation [7]. Around the

corner, waste from construction industry especially concrete

waste from demolition activities contributes 40 % of the

material waste sent to open landfill around the world and this

is a global problem [20]. The approximate percentage of

various construction materials in demolition waste [18] is

presented in Figure 1.2. In Malaysia, most of the construction

waste industry especially reinforced concrete from old

building is directly disposed to open landfill without

undergoing any treatment or separation between concrete and

reinforcement.

Fig. 1.2. Percentage of demolition wastes, Nik (2005).

Continuous industrial development produces serious problems

of construction and demolition waste disposal [3]. There is an

increasing shortage of natural aggregates (NA) for production

of new concrete for new structural construction project, on the

other hand, the enormous amounts of demolished concrete

produced from deteriorated and obsolete structures create

severe ecological and environmental impact problem [8].

One way to solve this problem is to reuse this concrete waste

material (Figure 1.3) as new aggregate in new construction

[15]. Reuse of concrete waste as recycled aggregate in new

concrete is beneficial from the view point of environmental

protection and resources reservation [22]. Since the proposal

of using Crushed Concrete Waste Aggregate (CCwA) (Figure

1.4) as coarse aggregate in concrete mix for reinforced

concrete structural element is still new in Malaysia and the

literature on the ultimate strength of these structures with

CCwA is limited, the research on waste materials will provide

a greater understanding on the structural behaviour of

reinforced concrete structures incorporating CCwA. As such

efforts are undertaken to study the consumption of CCwA as

coarse aggregate in reinforced concrete short wall panel. This

research is to determine the structural behaviour of CCwA

reinforced concrete short wall panel using steel fabric as

reinforcement, as there is none so far carried out in Malaysian

construction industry. Furthermore there are no specific basic

design guidelines for this type of structure element. The

ultimate strength and the mode of failure of the wall panel are

presented in the following chapters.

Fig. 1.3. Waste Concrete Material



Fig. 1.4. Crushed Concrete waste Aggregate (CCwA)

2.0 THEORETICAL ANALYSIS

2.1.1 Wall reinforcement

The reinforced concrete short wall panel design according to

BS 8110 Part 1:1997 [5], the samples were designed as a

stocky reinforced concrete walls as in clause 3.9.3.6. Stocky

wall is a wall where the effective height divided with

thickness; le/h does not exceed 15 for braced wall and 10 for

unbraced wall. In this case, wall panel was categorized as a

unbraced short wall panel. The B7 steel fabric that used for

reinforced concrete short wall panel in this experimental is

satisfied by the general code for design.

2.1.1.1 Minimum area of vertical reinforcement

The area of vertical displacement should not exceed 4% of

the total gross-sectional area of the concrete as prescribed in

clause 3.12.6.3. In this sample of size 75mm x 500mm x 1000

mm (Thickness:Height:Length), amount of reinforcement used

is 1%, the percentage allowable [5].

2.1.1.2 Area of horizontal reinforcement

The area of horizontal reinforcement in walls where the

vertical reinforcement resists compression and does not

exceed 2 % according in clause 3.12.7.4 in BS 8110 Part

1:1997as

fy = 250 N/mm2

0.3% of concrete area

fy = 460 N/mm2 0.25% of concrete area

Similarly in this experiment sample, the horizontal

reinforcement used is 0.6%; the percentage is also allowable.

2.1.1.3 Walls supporting mainly axial load

If the wall supports an approximately symmetrical

arrangement of slabs, the design axial load capacity nw per

unit length of wall is given by;

Where;

= ultimate axial load per unit length

fcu = characteristic strength of concrete

Ac = gross area of concrete per unit length of wall

Asc = area of compression reinforcement per unit length of the

wall.

From the theoretical calculation of the ultimate strength

described in the equation above for reinforced concrete short

wall panel. The theoretical calculations design, consider the

single and double layer of steel fabric as reinforcement. The

ultimate load from theoretical calculation for single and

double layer by using CCwA as coarse aggregate is 1024 kN

and 1149 kN respectively.

3.0 MATERIAL AND METHODOLOGY In this section, the detail of CCwA reinforced concrete short wall

panel samples and the experimental set up are described.

3.1 Wall Panel Construction

The experimental work involved construction of ten (10)

samples of steel fabric reinforced concrete short wall panel of

size 75mm x 500mm x 1000 mm (Thickness:Height:Length)

with aspect ratio (h/L) of 0.5 and slenderness ratio (h/t) of

6.67. The detail description of reinforced concrete short wall

panel is shown in Table 3.1. The properties of the material

used have been confirmed earlier before preparation of the

wall sample by conducting cube and steel fabric strength tests.

Figure 3.1 shows the process of preparing the short wall panel.

The structural behaviour of short wall panel in term of

ultimate strength load and mode of failure were determined.

The wall panels were constructed using concrete Grade 30 by

using Ordinary Portland Cement (OPC) and using Crushed

Concrete Waste Aggregate (CCwA) as a coarse aggregate,

totally replacing Natural Aggregate (NA) in concrete mix with

water cement ratio of 0.50. The sizes of CCwA used were of

10 mm and 20 mm, similar to natural aggregate sizes and steel

fabric type B385 (B7) with fy of 485 N/mm2 was used as

reinforcement. The CCwA was crushed using jaw crusher and

sieved into the desired sizes as according to the design mix.

The detail dimension of reinforced concrete short wall panel is

shown in Figure 3.2. This study was conducted with support

condition considered as pinned at the upper end and fixed at

the lower end. The short wall panel was tested subjected to

compressive axial and fatigue loads using CCwA.

3.2 Experimental Set-up

The testing of reinforced concrete short wall panels was

conducted in the Heavy Structure Laboratory, Faculty of Civil

Engineering UiTM Shah Alam. Experimental work involved

the testing of ten (10) reinforced concrete short wall panels.

There are two types of test that were conducted in the

laboratory which are fatigue and static compression tests set

up in the reaction frame of two (2) Universal Testing

Machine. The load cell has a maximum capacity of 2000 kN

and 1000 kN capacity respectively and were placed at the

20 mm 10 mm



Waste Concrete

Ready for Crushing

Jaw

Cru

sher

CCwA

FormworkConcreting workWall Panel

Process

to make the

Short Wall

Panel

upper end of the sample. Hydraulic jacks are fixed to the main

testing frame to allow the load to be transferred using

hydraulic system. The samples were tested by using Universal

Testing Machine (UTM) capacity 1000 kN in Heavy

Structures

Laboratory.

Figure 3.3 (b) shows the reaction frame that was used in this

experiment.

Fig. 3.1. Casting of short wall panel

(a) Single layer steel fabric

(b) Double layer steel fabric

Fig. 3.2. Detail for reinforced concrete short wall panel

T ABLE 3.1 DETAIL DESCRIPTION OF REINFORCED CONCRETE SHORT WALL PANEL

Type of testing Axial load Fatigue load

Variation Single layer steel

fabric

Double layer

steel fabric

S ingle layer

steel fabric

Double layer

steel fabric

Crushed concrete waste aggregate

2 2 1 1

Natural Aggregate 1 1 1 1



Linear variable differential transducers (LVDT) were used to

measure displacements, perpendicular to the height, and any

small movement of the wall panels. They were placed at

various locations on the front surface of short wall panel as

shown in Figure 3.6. The magnitude of displacement was

measured by using three (3) transducers (T3 – T5). The

function of transducers 3, 4, and 5 is to measure the lateral

profile of short wall panel during testing and to monitor any

twisting of short wall panel. The load cell and the transducers

were connected to a portable digital electronic data logger. In

this experiment, four (4) strain gauges were placed on the steel

fabric at the front and rear sides of wall panel, two (2) on each

layer of the steel fabric whereas two (2) strain gauges were

placed on the steel fabric for single layer steel fabric. Strain

gauges were used to identify the strain in the steel fabric

during testing. The position of strain gauges placed on the

steel fabric of the wall panel, located at 0.5L and 0.7L at 250

mm and 375 mm of the height of the short wall panel as

shown in Figure 3.7. Instruments should be installed properly

before starting applying the load to the wall panel. The wall

panel was loaded up until failure. At each load increment,

mode of failure and displacement were recorded. The pattern

of cracks was recorded and width and length of the crack were

measured. The data from strain gauge and LVDT were record

automatically by data logger which was connected to the

computer. Every load increment, deflection or deformation

has been recorded. Figure 3.8 shows the final set-up for

fatigue and static compression testing.

Fig. 3.6. Arrangement of LVDT

Fig. 3.7. Arrangement of strain gauge

(a) (b)

Fig. 3.8. Final set-up of short wall panel



3.2.1 Static compression test

Under the static compression testing, six (6) samples were

tested to identify the behaviour of reinforced concrete short

wall panel under static compression test. Figure 3.3 (a) shows

the reaction frame that was used for this experiment and

Figure 3.3 (b) shows the reaction frame for fatigue test. The

wall panel was placed vertically on C-channel, with the lower

end support fixed accordingly in the centre of the reactions

frame. The boundary condition is set to allow for rotation and

to prevent the lateral deformation at the top of the wall, and to

prevent both the rotation and lateral deformation at the lower

part of the wall. The steel support was used to prevent the

movement of reinforced concrete short wall during the testing.

U-Channel and rubber pad was used at the lower ends for

purpose of fixing the wall panel. The steel base was clamped

to the strong floor. The load was applied until ultimate with,

the displacement began to increase drastically, and then the

test was stopped. The detail of the front view and side view of

the experimental set-up for static compression testing are

shown in Figure 3.4.

(a) UTM 2000 (b) UTM 1000

Fig. 3.3. Universal testing machine for static and fatigue loads testing



3.2.2 Fatigue compression test

The remaining four (4) wall panel samples were tested under

fatigue loading, namely single and double layered steel fabric

wall CCwA and NA. In fatigue test, the UTM machine was

set with maximum and minimum load of 300 kN and 30 kN

respectively with frequency of 5Hz applied at the top surface

of reinforced concrete short wall panel. The cycle was set until

1 million cycles and any cracks or failures were checked

during the loading process. The hydraulic load cell transmitted

a vertical fatigue loading to the top of the wall panel in order

to achieve the pinned support at the upper end and fixed

support at the lower end. Steel U-channel was used at the

upper and lower ends of the wall panel that hold the sample

during testing, however at the bottom of the sample there was

a rubber pad being used between the sample and the wall

panel. The function of rubber pad is to fill up the space

between the sample and steel U-channel to fix the sample at

the lower end. The steel rod and the steel plate acted for

transferring the load to the top surface of wall panel. The steel

angle at both sides of the wall panel was installed to act as a

guide for wall panel from moving during the experimental

work. Detailed schematic diagrams of experimental set-up for

fatigue testing are shown in Figure 3.5.

Fig. 3.5. Experimental set up for Fatigue testing using Universal Testing Machine 1000 kN capacity

Fig. 3.4. Experimental set up for static compression testing using Universal Testing Machine 2000 kN capacity



4.0 EXPERIMENTAL RESULTS AND DISCUSSIONS

The result presented herein is according to ultimate load under

static load, deflection profile, crack pattern, stress and strain

and maximum cycles under fatigue testing.

4.1 Compressive Behaviour

In compressive behaviour the wall panels were tested under

compressive load until the wall panels failed at ultimate load.

From experimental result, the average ultimate load for SLAL

(CCwA) and DLAL (CCwA) show higher value than the

theoretical calculation of about 24% and 30% which is 1349

kN and 1644 kN respectively. From the result comparison, it

shows that using double layer steel fabric give 18% more

strength to wall panel compared with using single layer of

steel fabric. On the other hand, the ultimate load from

theoretical calculation for single and double layer steel fabric

using NA is 1073 kN and 1197 kN respectively. However, the

result for both samples from the experimental shows higher

than theoretical calculation of about 25% and 32 % which is

1428 kN and 1760 kN respectively. From result analysis, the

percentage of ultimate strength for single and double layer

increase significantly. Therefore, percentage difference of

average ultimate strength between single and double layer is

18 %, it showes that, the different of ultimate strength between

this parameter is not significant when using single and double

layer of steel fabric in reinforced concrete short wall panel. As

such from this study, a single layer steel fabric of wall panel

can be used as load bearing wall panel with higher ultimate

strength. It’s supported by cost calculation of wall panel, the

reinforced concrete with double layer steel is 10 % more

expensive compared with single layer steel fabric. Therefore,

the design for using of wall panel in structural application is

based on types of structure in term of ultimate strength range.

The comparison of ultimate strength for short wall panel by

using CCwA and NA shows the similar performance, it

support by Levy and Helene [16], they reported compressive

strength of concrete made from recycled concrete aggregate

with 20%, 50%, and 100% replacement could have equal fresh

workability and also can obtained the compressive strength in

range 20-40 MPa at 28 days. Table 4.1 shows detail of

experimental result and theoretical calculation of wall panel.

Figure 4.1 shows the graph of ultimate load nw and maximum

deflection result.

T ABLE 4.1

EXPERIMENTAL AND THEORETICAL RESULT

Sample Ultimate Load (kN)

(Experimental)

Ultimate Load (kN) from BS

8110 (Theoretical)

Percentage

Differences (%)

SLAL (CCwA) 1 1380 1024 26%

SLAL (CCwA) 2 1318 1024 22%

DLAL (CCwA) 1 1598 1149 43%

DLAL (CCwA) 2 1689 1149 32%

SLAL (NA) 1428 1073 25%

DLAL (NA) 1760 1197 32%

Note: SLAL (CCwA) : Single Layer steel fabric with Axial Load by using Crushed Concrete Waste Aggregate

DLAL (CCwA) : Double Layer steel fabric with Axial Load by using Crushed Concrete Waste Aggregate SLAL (NA) : Single Layer steel fabric with Axial Load by using Natural Aggregate DLAL (NA) : Double Layer steel fabric with Axial Load by using Natural Aggregate



Fig. 4.1. Ultimate load vs Displacement for all samples

4.2 Deflection Profile

The deflection result from experiment was measured from

LVDTs that were placed at various locations on the front

surface of the wall panel. The LVDTs were directly connected

to a portable digital electronic data logger. The maximum

deflection for all reinforced concrete short wall panels occurs

at 0.7H of total height of wall panel which is 375 mm from the

top. Detailed deflection profile summary results for all

samples are shown in Table 4.2. Location of maximum

deflection for all samples happened at the same place which is

at 0.7H; it means the position of maximum deflection support

the Euler Buckling Theory for pinned-fixed end condition.

Figure 4.2 shows the deflection profile of wall panel. In Figure

4.2, all the samples showed a single curvature pattern with

maximum deflection occur at 0.7H of wall panel. It is

supported by Wang [20], tested wall panel under action with

eccentric load top and bottom of wall deflected with single

curvature. The average maximum deflection for SLAL

(CCwA) and DLAL (CCwA) is 2.90 mm and 3.75 mm, which

is 28% and 6% lower than theoretical calculation. However,

the maximum deflection for control sample SLAL (NA) and

DLAL ((NA) is 7.95 mm and 6.80 mm, which is 50% and

41% respectively higher than theoretical calculation. The

results show, maximum deflection for samples with NA is

higher than samples with CCwA as a coarse aggregate. From

comparison between single and double layer in term of

deflection, the double layer shows higher deflection compared

with single layer steel fabric about 23 %. Based on the results,

the double layer steel fabric can support the higher load and

can be considered good to reduce the propagation of cracks

before the structure wall panel failed compared to single layer

steel fabric. But from the percentage increase value, the

double layer did not prevail higher ultimate load and SLAL

could be considered good enough as reinforced concrete wall

panel according to British Standard because it reported

allowable displacement. Therefore, for the design purpose of

reinforced concrete short wall panel, it should consider the

ultimate load and deflection range in term of cost, because the

cost increases by 10% in the case of using double layer steel

fabric in short wall panel.

0

500

1000

1500

2000

2500

0 5 10

Ult

imate

L

oad

(kN

)

Displacement (mm)

ULTIMATE LOAD VS DISPLACEMENT

SLAL (CCwA) 1

SLAL (CCwA) 2

DLAL (CCwA) 1

DLAL (CCwA) 2

SLAL (NA)

DLAL (NA)

1318

1689

1380

1598

1760

1428



Fig. 4.2. Deflection profile for all sample

Figure 4.3 shows the displacement profile for single and

double layer reinforced concrete wall panel at point T5 located

at 0.7H. Four (4) point of load were considered to plot this

graph, which is Pinitial, P50% , P80% , and Pult. The figure contains

single and double layer graphs so that the different behaviour

of wall panel in term of deflection under ultimate loading can

0

100

200

300

400

500

0 3 6 9

Heig

ht

(mm

)

Displacement (mm)

Wall Profile vs Displacement for

All Samples

SLAL (CCwA) 1

SLAL (CCwA) 2

DLAL (CCwA) 1

DLAL (CCwA) 2

SLAL (NA)

DLAL (NA)

T ABLE 4.2 DEFLECTION PROFILE SUMMARY

Sample SLAL (CCwA) 1

(1380 kN)

SLAL (CCwA) 2

(1318 kN) Height

(mm) Load P50% P80% Pultimate P50% P80% Pultimate

Dis

pla

cem

en

t (m

m)

T3 1.30 1.26 1.26 0.26 0.26 0.30 375

T4 1.84 1.80 1.76 0.51 0.55 0.70 250

T5 4.25 4.28 4.31 1.32 1.38 1.48 125

(a) Displacements detail for SLAL (CCwA) 1 and SLAL (CCwA) 2

Sample DLAL (CCwA) 1 (1597 kN)

DLAL (CCwA) 2 (1689 kN)

Height (mm)

Load P50% P80% Pultimate P50% P80% Pultimate

Dis

pla

cem

en

t

(mm

)

T3 0.74 1.11 1.41 0.30 0.89 1.56 375

T4 1.10 1.62 2.09 0.36 2.63 2.83 250

T5 2.28 3.32 4.23 0.95 1.98 3.27 125

(b) Displacements detail for DLAL (CCwA) 1 and DLAL (CCwA) 2

Sample SLAL (NA)

(1428 kN)

DLAL (NA)

(1760 kN)

Height

(mm)

Load P50% P80% Pultimate P50% P80% Pultimate

Dis

pla

cem

en

t

(mm

)

T3 2.63 3.37 3.63 0.90 2.82 4.19 375

T4 3.82 4.99 5.40 1.41 2.82 6.15 250

T5 6.18 7.41 7.95 2.46 4.60 6.79 125

(c) Displacements detail for SLAL (NA) and DLAL



0

2

4

6

8

0 500 1000 1500 2000

Dis

pla

cem

en

t (m

m)

Load (kN)

Displacement vs Load for Double

Layer at maximum point

DLAL (CCwA) 1

DLAL (CCwA) 2

DLAL (NA)

0

2

4

6

8

0 500 1000 1500

Dis

pla

cem

en

t (m

m)

Load (kN)

Displacement vs Load for Single

Layer at maximum point

SLAL (CCwA) 1

SLAL (CCwA) 2

SLAL (NA)

be compared. Figure 4.3 (a) shows the displacement increases

linearly until point P50%, after that point, the displacement

increases slightly especially for CCwA sample. It shows, that

the sample using CCwA gives lower strength and durability

under compressive load compared with using NA because of

the behaviuor of recycled aggregate. Apart from that, the

result for double layer in Figure 4.3 (b) shows the

displacement increases linearly until the wall panel totally

fails at ultimate load. From the result, we can also observe the

double layer sample using CCwA gives a lower performance

compared with sample using NA.

4.3 Crack Pattern

The crack pattern of wall panel was observed during and after

the experimental work in the heavy structure laboratory.

Based on observation during experiment, most of the crushing

cracks happened on samples which used single layer of steel

fabric in wall the panel especially at the top and bottom

locations of the wall panel. Experimental results from Ruzitah

[19] also reported that, the wall panel crushed at the base

because of the well load distribution happened within the

concrete matrix; it also showed that compression failure at the

lower end of wall panel without any major crack on the

surface of wall panel. Based on graph displacement profile at

maximum point T5 above, for single layer samples crack was

started at P50% load and totally failed at Pult. But for the double

layer samples, it was difficult to see the crack pattern at P50%

load until major crack occurred at Pult when the samples totally

failed. The observation is supported by the graph above, the

load increased linearly with displacement until failure at

ultimate load. Table 4.3 shows the detail descriptions and

location of crushing crack for each sample at ultimate load.

According to BS 8110: Part 1: 1997 [5] in clause 3.9.3.5

arrangement of reinforcement for reinforced walls in tension

which states that, in any part of reinforced wall where tension

occurs under ultimate load, the reinforcement must be

arranged in two layer and every layers must be in accordance

with the bar spacing requirement. The observation supported

the clause in BS 8110 that double layer of steel fabric gave

more prevention of cracking to wall panel. Using CCwA as a

coarse aggregate did not affect the behaviour of reinforced

concrete wall panel in term of cracking pattern. Result from

experiment shows the similarity in term of cracking by using

CCwA as a coarse aggregate replacing the NA in concrete

mix. Figure 4.4 shows the typical of cracking on short wall

panel.

(a) (b) Fig. 4.3. Displacement profile at maximum point T5 for single and double layer wall panel

T ABLE 4.3 DESCRIPTION AND LOCATION OF CRACK AT PULT FOR ALL SAMPLES

Sample Crack Location Side Crack Surface Crack

SLAL (CCwA) 1 Crushed at upper

and lower of the wall Crack at the

top wall panel None

SLAL (CCwA) 2 Crack at bottom

of wall panel

Crack on left edge at

the bottom wall panel

Crack on front surface at

the bottom wall panel

DLAL (CCwA) 1 Crushed at upper

and lower of the wall None None

DLAL (CCwA) 2 Crushed at upper

and lower of the wall

Crushed at left and right

side edge wall panel None

SLAL (NA) Crushed at upper

and lower of the wall Crack on both side at the top

Crack on front and rear surface at the middle of

wall panel

DLAL (NA) Crushed at upper

and lower of the wall None None



(a) Front of wall panel

(b) Rear of wall panel

(c) Surface failure at the top wall panel

(d) Crushing and crack at the top of wall panel

(e) Side failure of wall panel

(f) Crack failure at the top of wall panel

(g) Surface crack on wall panel (h) Crushing failure at the bottom of wall panel

Fig. 4.4. Crushing and crack of wall panel



0

5

10

15

20

25

0 500 1000

Str

ess

(N/m

m2)

Strain µm/m

DLAL (CCwA) 1

LF 250LF 375LR 375

0

5

10

15

20

25

0 500 1000 1500 2000

Str

ess

(N/m

m2)

Strain (µm/m)

DLAL (CCwA) 2

LF 250

LF 375

LR 375

LR 250

0

4

8

12

16

20

0 50 100 150 200

Str

ess

(N

/mm

2)

Strain (µm/m)

SLAL (NA)

L 375

L 250

0

5

10

15

20

25

0 100 200 300 400 500 600

Str

ess

(N

/mm

2)

Strain (µm/m )

DLAL (NA)

LF 250

LF 375

LR 375

LR 250

4.4 Stress and Strain

The stress-strain of longitudinal bars is directly proportional

with respect to the increasing load that was applied on the

surface of wall panel [19]. Figure 4.5 shows the graph of

stress versus strain for all wall panel samples. From the graph

profile the strain of steel fabric is found directly proportional

with the stress. Maximum compressive stress was recorded by

DLAL (CCwA) with 23464 kN/m2, however the lowest stress

was recorded by SLAL (CCwA) 2 with 17575 kN/m2. This

situation was expected because the double layer of steel fabric

gives more strength to the wall panel. The average maximum

compressive stress for SLAL (CCwA) is 18041 kN/m2.

Therefore, the percentage of average maximum compressive

stress between experimental and theoretical calculations for

single layer steel fabric wall panel using CCwA is 24% higher

than theoretical calculations. On the other hand, the average

maximum compressive stress for DLAL (CCwA) is 21915

kN/m2, but the theoretical calculation shows a 30% lower

value than experimental result. Table 4.4 shows the detail of

the stress-strain measurements of steel fabric. From

experimental result that is shown in the table, the sample with

CCwA as a coarse aggregate gives lower compressive stress

of about 5.3% for single layer and 6.6% for double layer

respectively of the wall panel compared with NA. These

shows, NA as coarse aggregate gives more strength to the wall

panel. Replacement of 50% and 75% of RCA shows an

increased in strength compared with 25 % and 100%

replacement of aggregate, replacement 100% of RCA in

concrete mix could reduce the strength of concrete by 7.2 %

for 7 days and 8% for 28 days [2]. In the concrete construction

the RCA has similar performance with natural aggregate [17].

Therefore, for concrete producers, the replacement of natural

aggregate in concrete mix is not a big problem in production

because of the similar properties with natural aggregate. The

strain gauge result shows the maximum of strain for steel

fabric occurs at location 0.7H which is 375 mm from the top

of short wall panel. All strain gauge were install at steel fabric

reinforcement shows increase linearly with respect to the

applied load on the top surface of wall panel. The maximum

strain was recorded to be 5.536 𝜇m for sample SLAL (CCwA)

2, a reason for why this sample recorded higher strain is

because the sample totally failed at ultimate load with

cracking at the bottom of the wall panel at location where

strain gauges were installed. However, the double layer steel

fabric shows the lowest strain compared with single layer steel

fabric. During observation, the cracking of wall panel initiated

when the steel fabric started to bend during the loading on the

top of the wall panel and automatically cause the samples to

fail.

0

5

10

15

20

0 1000 2000

Str

ess

(N

/mm

2)

Strain (µm/m )

SLAL (CCwA) 1

L375

L250

0

4

8

12

16

20

0 2000 4000 6000

Str

ess

(N

/mm

2)

Strain µm/m

SLAL (CCwA) 2

L375

L250

Fig. 4.5. Stress-strain relationship for axial load testing samples



4.5 Fatigue Testing

The structural behaviour for fatigue samples of reinforced

concrete wall panel were analyzed after the experimental work

at laboratory completed and the reading from load cell and

strain gauges at the steel fabric reinforcement were collected.

Figure 4.6 shows the details of the displacement profile for all

four (4) samples of short wall panel. The maximum

displacement was recorded by sample with CCwA as a coarse

aggregate with 0.947 mm for sample DLFL (CCwA). The

percentage difference in displacement between samples is 33

% higher for DLFL (NA) in comparison to the DLFL (CCwA)

sample. Result for SLFL reported the same behaviour of

displacement which is that SLFL (NA) gives 5 % higher value

than SLFL (CCwA). It shows, the recycled aggregate is easily

susceptible to failure under fatigue load because of the weak

bonding strength between the coarse aggregate particles

compared with NA. From the graph of displacement verse the

numbers of cycle shows the maximum cycle for wall panel.

The maximum cycle until the wall panel experienced failure

for SLFL (CCwA) and SLFL (NA) is 520325 cycles and

600325 cycles respectively. For the double layer steel fabric

sample DLFL (CCwA) and DLFL (NA) is 690450 cycles and

770450 cycles respectively. Table 4.5 shows the detail result

of short wall panel under fatigue testing. From the result, the

numbers of cycles for double layer steel fabric were recorded

higher than single layer steel fabric and directly give more

strength to the wall panel. However, wall panel using CCwA

as a coarse aggregate was observed to fail easily by cracking

compared with wall panel using NA as a coarse aggregate.

This was supported by Ajdukiewicz and Kliszczewicz [1],

who studied on bond strength of Recycled Aggregate Concrete

(RAC), a reduction of more than 10% in the bond strength of

the RAC for 100% replacement in mix design concrete. The

porosity of concrete made from CCwA gives an effect to wall

strength, study from Gomez-Soberon [11], the porosity

increased when NA were replaced by CCwA. Compressive

and tensile strength performance decreased when higher

porosity in concrete structure as well as in modulus of

elasticity. It showed that, using NA is better compared with

using CCwA under fatigue load. It could conclude that,

CCwA is not suitable for structures under fatigue load,

because of the weak bonding strength of aggregate that causes

failure to the wall panel. The coarse angularity and the

residual cementation on the surface of CCwA also affected

the bonding strength of concrete when fatigue load was

applied. From the failure observation, the short wall panel

failed by diagonal tension failure when crack appeared at

corner of wall panel. Apart from that, the wall panel also

crushed in the compressive zone at the base of the wall panel.

The wall panel failed by diagonal compression when adequate

horizontal reinforcement was provided under fatigue load

[12]. Figure 4.7 shows the typical cracking of reinforced

concrete wall panel under fatigue load. The graph shows the

maximum displacement and numbers of cycles of the fatigue

loading test on short wall panel.

T ABLE 4.4 T HE DETAIL OF THE STRESS- STRAIN MEASUREMENT OF STEEL FABRIC

Sample

Maximum

Stress

(kN/m2)

(Experimental)

Maximum

Stress

(kN/m2)

(Theoretical)

Strain

Longitudinal Steel

Fabric

(𝜇m)

Failure Mode Remark

SLAL (CCwA) 1

18507 13661 L250 = 1.449 L350 = 2.128

Crushing at upper and lower

Maximum strain occur at ¾ of wall

height

SLAL

(CCwA) 2 17575 13661

L250 = 1.417

L350 = 5.536

Crack at the base

of wall panel

Maximum strain

occur at ¾ of wall

height

DLAL

(CCwA) 1 21303 15313

LF250 = 0.708

LR250 = None

LF350 = 0.796 LR350 = 0.750

Crushing at upper

and lower

Maximum strain

occur at ¾ of wall

height

DLAL

(CCwA) 2

22526

15313

LF250 = 1.153

LR250 = 0.800

LF350 = 1.980 LR350 = 0.262

Crushing at upper

and lower

Maximum strain

occur at ¾ of wall height

SLAL (NA)

19046 14301 L250 = 0.166 L350 = 0.114

Crack at the top

and base of wall panel

Maximum strain

occur at the middle of wall height

DLAL (NA)

23464

15954

LF250 = 0.350

LR250 = 0.428 LF350 = 0.505

LR350 = 0.353

Crushing at upper and lower

Maximum strain

occur at ¾ of wall height



T ABLE 4.5 DETAIL CYCLE AND DISPLACEMENT OF WALL PANEL UNDER FATIGUE TEST

Sample Failure at

Cycle

Vertical Maximum

Displacement

(mm)

SLFL (CCwA) 520325 0.799

DLFL (CCwA) 690450 0.947

SLFL (NA) 600325 0.761

DLFL (NA) 770450 0.637

Note: SLFL (CCwA) : Single Layer Fatigue Load by using Crushed Concrete Waste Aggregate

DLFL (CCwA) : Double Layer Fatigue Load by using Crushed Concrete Waste Aggregate

SLFL (NA) : Single Layer Fatigue Load by using Natural Aggregate

DLFL (NA) : Double Layer Fatigue Load by using Natural Aggregate

Fig. 4.6. Graph maximum displacement vs Number of cycles

0.55

0.65

0.75

0.85

0.95

1.05

500000 600000 700000 800000

Ma

x D

isp

lecem

en

t (m

m)

Numbers of Cycles, N

Maximum displacement vs

Numbers of cycles

SLFL (CCwA)

DLFL (CCwA)

SLFL (NA)

DLFL (NA)

690450

520325

600325

770450



(a) Side view of crack failure

(b) Detail view for side failure

(c) Front view failure on wall panel

(d) Rear view of cracking failure

(e) Surface crack of wall panel (f) Cracking at the middle of wall panel

(g) Cracking occur at the corner of wall panel (h) Cracking occur at the rear of wall panel

Fig. 4.7. Mode of failure for short wall panel under fatigue load



5.0 CONCLUSION

The average ultimate loads for SLAL (CCwA) and DLAL

(CCwA) under compression load test were found to be 1349

kN and 1643 kN respectively. The percentage comparison

of average ultimate strength from experimental shows 24%

and 30% higher than theoretical calculation. The result of

ultimate load for SLAL (NA) and DLAL (NA) shows 6%

and 8% higher values compared with sample using CCwA.

Most of the major cracking occurs on sample with single

layer steel fabric. Maximum deflection for all samples

occurs at the same place and location which is 375 mm

(0.7H) from the total height of the wall panel. The

displacement for wall panel using CCwA was recorded to

range from 4.31 mm to 1.48 mm. The percentage of average

maximum compressive stress between experimental and

theoretical calculations for single and double layer steel

fabric wall panel using CCwA are 24% and 30% higher

than theoretical calculations. During analysis, the sample

using CCwA as a coarse aggregate gives higher stress of

about 2.8% for single layer and 6.6% for double layer steel

fabric respectively compared with NA. The strain gauge

result shows the maximum of strain for steel fabric occurs at

location of 0.7H which is 375 mm from the top of wall

panel with 5.536 𝜇m. During fatigue testing, the wall panel

failed by diagonal tension failure when crack at the corner

of wall panel. On the other hand, the wall panel also crushed

in the compressive zone at base of the wall panel. From the

observation, the double layer steel fabric using CCwA as a

coarse aggregate was easily prone to failure because of the

low bonding strength between the CCwA particles under

fatigue loading. . It shows that the ultimate load of

reinforced concrete wall panel using CCwA is similar to the

wall panel which used NA in term of carrying capacity. The

experimental results show that, the wall panel using CCwA

show similar structural behaviour in term of ultimate load,

displacement profile, and mode of failure. Based on the

result, the reinforced concrete wall panel can sustain higher

loading without remarkable failure especially when

designed with double layer steel fabric, therefore wall panel

also can be promoted as a load bearing unit. But for design

purposes, the basic design criteria of short wall panel should

follow all the parameter in this research such as dimension,

grade of concrete, ratio and arrangement of steel fabric, and

the range of ultimate load for the infill wall in construction

application. When CCwA are accepted in present

construction method, the cost and the environmental load in

term of concrete waste would decrease compared to the

construction without the use of recycled material especially

for large-scale construction.

ACKNOWLEDGEMENTS

The authors express their sincere gratitude to the Faculty of

Civil Engineering, UiTM Malaysia for providing the

laboratory and testing facilities during the conduct of this

research.

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aggregates on mechanical properties of HS/HPC. Journal Cement Concrete Composites 2002;24:269-79

[2] Ahmad Ruslan.M.R., Sulaiman H., Ahmad Z.M.N., (2009),

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recycled construction and demolition waste in concrete, Journal of Resources, Conservation and Recycling 50 (2007) 71-81

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