Using Recycled Waste Tyre in Concrete Paving Blocks

7/28/2019 Using Recycled Waste Tyre in Concrete Paving Blocks

1/14

First author: [email protected] ; [email protected] Page 1

Original citation:Ling, T.C., Nor, H.M., Lim, S.K. (2010) Using recycled tyres in concrete paving blocks.

Proceedings of the ICE- Waste and Resources Management; 163 (1): 37-45.http://www.icevirtuallibrary.com/content/article/10.1680/warm.2010.163.1.37

Using recycled waste tyre in concrete paving blocks

T. C. Ling*, H. M. Nor, S. K. Lim

Abstract

There is general agreement amongst stakeholders that waste tyres should be better ma-

naged both to preserve valuable resources and to prevent environmental damage due to

improper disposal. The objective of this study is to promote a practical use and acceptance

of disposing crumb rubber in concrete paving blocks (CPB) by end user. Existing CPB is

characterized as a composite material with high compressive strength but with a low

toughness. By adding rubber into CPB, the toughness is improved while meeting minimumstrength requirements. A total of 4300 rubberized concrete paving blocks (RCPB) were

produced in a commercial plant, and 348 RCPB were tested for compression and abrasion

performance as prescribed by the Concrete Masonry Association of Australia (CMAA). In

addition, sound absorption, voids and skid resistance were tested in accordance to Ameri-

can Society for Testing and Materials (ASTM). The tests results revealed that the rubber

substitution should not exceed 20 % by sand volume, which caused excessive reductions in

compressive strength. Further investigations showed that sound absorption and toughness

was improved as the rubber content in the mix increased. The RCPB specimens had a sig-

nificant capability in absorbing dynamic loading and in resisting crack propagation. Such

behaviour may be beneficial for pavements that require good impact resistance properties.

Keywords: Materials technology/ Recycling of materials/ Strength and testing of materials

1. Introduction

Industrial by-products that would otherwise be discarded as harmful environment pollu-

tants are being widely used as cement or aggregate replacement in concrete. For both envi-

ronmental and economic considerations, industrial by-products or solid wastes are fast be-

coming vital sources for aggregate replacement in concrete. Therefore, there are increasing

demands in finding a possibility of recycling and applying the waste materials from con-

struction industry into civil engineering application. One of the examples is by using in-

dustry by-products and solids wastes in highway construction.In some Asian countries such as Hong Kong, Japan and Thailand, waste management

has become an acute problem as urbanization process and economic development increase

rapidly, leading to larger quantities of waste materials requiring proper management. Most

of the time, the disposal of solid waste is done solely through landfill. With regard to that,

waste minimization, reuse, material recycling, and energy recovery are encouraged instead

of disposal through landfills. In order to promote such initiatives, a number of research

studies were conducted in these countries in the area of utilizing industrial by-products or

solid wastes in concrete paving block (CPB) production.

In Hong Kong, the construction industry generates very large amount of solid wastes

such as crushed clay brick, crushed ceramic tile, crushed waste glass, wood chips, etc.


2/14

2

Numerous studies on the applications of construction and demolition (C&D) wastes as fine

and coarse aggregates material are available (Poon et al., 2002, Poon & Chan, 2006, Poon

& Cheung, 2007, Poon & Chan, 2007, Lam et al., 2007, Chan & Poon, 2006), which dem-

onstrated the possibility of utilizing huge amounts of C&D in concrete. The use of re-

cycled aggregates in CPB production has been successfully implemented and is gaining

wider acceptance. The environment benefits from the reduction of solid waste disposal in

landfills, in addition to that, the utilization of such solid waste also helps in preserving thenatural materials that would otherwise have been used in concrete production.

In recent years in Japan, the amount of coal ash produced by power plants has reached

about 27,000 tons daily (Karasawa et al., 2003). It is reported that the fly ash can be used

as a substitution for fine aggregate in the production of CPB. However, utilization of fly

ash can be accepted only when it meets the production target value with fly ash replace-

ment ratio of 25 %.

Some researchers had cited a large amount of literature on the applications of fly ash in

CPB (Phinyocheep, 1998, Nutalaya, 1994). It is estimated that about 45,000 tons of fly ash

lignite at Mae-Moh Power Plantis consumed daily for the generation of a 2,025 MW pow-

er plant in Thailand. Apart from fly ash, peanut shell ash and rice husk ash can be used as

partial replacement for cement in CPB production. Due to the issue of waste disposal and

environmental effect, the idea to utilize the fly ash is raised in the production of low-costCPB. Moreover, it will be helpful to the people who live in the vicinity of the power plant

and meet the demand of low income in rural areas.

2. Research background

One of the most common environmental issues in the contemporary world is related to

the management they are of pneumatic tyre, which is not readily biodegradable. Every

year, approximately 800 million new tyres are produced in every region of the world, in

various sizes and types (Serumagard, 1999).Although the lifetime of some tyres are pro-

longed, but ultimately they will be discarded as waste materials. Majority of such tyres

will end up in the already congested landfill or they become mosquito breeding places and

give the worst effects when burnt. The melting tyres also produced large quantities of oil,which will contribute to the contamination of soil and ground water.

Recent statistics in Malaysia indicated that there is an increase of more than 100 % in

the number of registered vehicles within these ten years. The current thirteen million ve-

hicles are producing a large number of scrap tyres. Therefore, the Department of Environ-

mental has put a stop to the open burning and burying of waste tyres as they will cause air

pollution and land instability. Even though several agencies and municipal councils are in-

volved in waste management, they often have no clear direction in relation to waste man-

agement. Only a few companies take the shredding process further by producing crumb

rubber and rubber powder. The cost of crumb rubber is about RM 1000 (1 US dollar = RM

3.5) per ton. Therefore, as an engineer and researcher, there is a need to seek and identify

economic and environmental friendly methods to manage these tyres in different civil en-

gineering applications.

For the last 20 years, introduction of scrap tyres rubber into asphalt concrete pavement

has solved the problem of waste tyres. Several investigations showed that strength and

compressibility of shredded tyres in concrete form can be engineered to meet the require-

ments by increasing the cement content. On the other hand, owing to the unique characte-

ristic of tyre (rubber), it is expected that by adding crumb rubber into concrete mixture, it

can increase the toughness (energy absorption capacity) of concrete considerably (Toutan-ji, 1996, Naik & Siddique, 2004, Li, et al., 2004, Hermandez-olivares et al., 2002, Ling


3/14


and Nor, 2007). However, the initial cost of rubberized asphalt is 40 to 100 % higher than

that of conventional asphalt, moreover, its long term benefits are uncertain (Fedroffet al.,

1996).

Limited laboratory tests results have shown that the incorporation of waste tyre rubber

(crumb rubber) in concrete pedestrian block, reduces the weight and considerably increas-

es toughness and skid resistance (Sukonrasukkul & Chaikaew, 2006). However, such

combination causes less abrasion resistant and is not as strong as the conventional block.Hence, the blocks produced are considered not applicable for trafficked pavement.

To resolve these problems (low strength and slow production by hand-pressed method),

various means are attempted to improve the strength and to reduce tyre wastes in a massive

quantity. This study is aimed to promote a practical use and acceptance of using crumb

rubber in CPB by potential end users. Therefore, an investigation of manufacturing

processes and feasibility of producing CPB incorporating crumb rubber in a commercial

plant setting is carried out. In addition to that, the CPB quality and strength are expected to

be improved by using specialised manufacturing equipment (under vibration and extreme

pressure) based on formulations developed in laboratory trials (Ling et al., 2009).

3. Experimental details

3.1. MaterialsThe rubber granules named crumb rubber used in this study were recycled from dis-

carded car tyre as shown in Fig. 1. Crumb rubber is a fine material and is produced by me-

chanical shredding with the gradation close to that of sand (Fig. 2). Two particle sizes of

crumb rubber: 1 3 mm and 1 5 mm were used as a partial substitute for fine sand and

coarse sand in facing layer and body layer, respectively in the production of CPB. All the

particle sizes of crumb rubber passed BS sieve no. 4 (4.75 mm).

Other concreting materials such as cement, sand, aggregates, additive (Rheobuild 1000

superplasticizer) and full-scale facilities of factory plant machine were supplied by a

commercial plant. The physical and mechanical properties of both sand and aggregate are

given in Tables 1 and 2, respectively. All materials used in this study are commercially

available in Malaysia.

Fig. 1. Waste car tyre being left at landfill Fig. 2. Crumb rubber


4/14

4

Table 1. Physical and mechanical properties of fine and coarse sand

Note: Fine sand used for facing layer; coarse sand used for body layer.

Table 2. Physical and mechanical properties of aggregate

3.2. Mix proportioning

The control CPB mix proportion of cement:aggregate:sand used was 1:1.9:3.8 by weight

with a additive-cement ratio of 0.06. The mix proportions used in the CPB products ranged

between 0.39 0.45water cement ratio (w/c) for 290 330 kg/m3

cement content, as ap-

propriate to the products under investigation. The volume fraction of rubber was varied as

0 %, 10 %, 20 % and 30 % named T1, T2, T3 and T4, respectively. Table 3 shows the

mixing proportioning for the components of these RCPB.A total of 4300 RCPB including

control samples were cast and 438 were tested.

Table 3. Mix proportioning per m3

Mix symbolMix ratio Cement content (kg) W/C ratio Rubber content (%)

Facing

(C:S)

Body

(C:A:S)Facing Body Facing Body Facing Body

T1 1:2.3 1:1.9:3.8 617 328 0.23 0.45 0 0

T2 1:2.1 1:1.9:3.4 585 317 0.23 0.43 8.8 9.7

T3 1:1.9 1:1.9:3.0 604 274 0.29 0.48 21.6 19.4

T4 1:1.7 1:1.9:2.6 574 286 0.26 0.39 30.4 29.0

Note: C:A:S = (cement:aggregate:sand)

3.3. Sample preparation

The method of manufacturing is called semi-dry pressing, it was used for RCPB plant

production. The mixed materials were moulded under a combined vibrating and compact-

ing action in an industrial setting to fulfill the requirement of maintaining a workable mix.Workability of concrete mixtures in plant production was not as important as in normal

concretes (Ling and Nor, 2006). The effect of rubber aggregate on the workability of the

modified concrete was minimal. Therefore, only a minimal amount of water was allowed

to make the mixture fluid enough to be fed into moulding machine.

Figure 3 shows the RCPB making process flowchart. Two independent mixers were

used with appropriate capacity and worked in parallel to ensure facing layer was added for

appearance. Initially, coarse sand, aggregate, cement, 1 5mm crumb rubber and additive

Property T1 & T2 T3 & T4

Passing 10mm (%) 86.2 98.2

Passing 5mm (%) 16.2 12.4

Flakiness index 17.1 22.1

PropertyT1 & T2 T3 & T4

Fine sand Coarse sand Fine sand Coarse sand

Silt content (%) 5.6 5.7 5.6 7.6

Moisture content (%) 5.2 8.5 5.2 9.0

Fineness modulus 1.8 3.0 1.8 2.9


5/14


were mixed in the body mix mixer. On the other hand, fine sand, aggregate, cement and 1

3 mm crumb rubber were mixed in the face mix mixer for approximately 1 min. After

mixing for 1 min, water was added to the materials in both mixers and mixed for another 1

min. The procedure of mixing and adding water was iterated until the desired moisture

content for these semi-dry mixtures was obtained.

The ready mixtures were transferred from the pan mixer to a feed hopper. The amount in

the feed hopper was controlled by an automatic weighting system. The hopper dischargedthe correct amount of concrete into the mould in the block making machine. The RCPB

were fabricated by block making machine in steel moulds with internal dimensions of 210

mm in length, 105 mm in width and 60 mm in depth. Firstly, the mould was filled with the

body mix and vibration and pressing were applied. The face mix was then poured into the

mould for the second layer, and then final compaction and vibration were applied for 4 s at

the frequency of 60 Hz. The hydraulic ram was released and the head lifted to allow early

stripping of RCPB from the steel moulds. The detailed process of making RCPB can be re-

ferred to previous research (Ling and Nor, 2006).

Fig. 3. CPB making process control flowchart

3.4. Test Method

To promote a good finished texture and strength of RCPB, the early trials need to be

done to ensure proper material proportions, water amount and adequate vibration and


6/14

6

compaction with a particular addition of crumb rubber content in RCPB. The quality as-

surance is defined as the implementation of a suitable set of pre-established and systemat-

ic intended dispositions for giving confidence in the obtaining of the required quality.

The implementation comprises measures: for raw materials before manufacturing for fresh products during the manufacturing for finished products after manufacturingAll the information which was gathered at different stages of the manufacturing

processes and noted in registers were compared with the manufacturing instructions in or-

der to detect and correct possible anomalies. With this, new fresh products introduce in

this study can be checked and observed during the manufacturing process.

For finished products, density, water absorption and voids in RCPB were examined us-

ing the (ASTM C 642, 2006) method. Each value represents the average of five samples.

With the procedures and formulations stated in the ASTM, absorption after immersion, ab-

sorption after immersion and boiling, bulk density (dry), bulk density after immersion,

bulk density after immersion and boiling, apparent density and volume of permeable pore

space (voids) were then determined.

The acoustic measurement obtained by using impedance tube (ASTM C 384, 2004)was

limited to the sound absorption coefficient.The sound absorption coefficient was measuredto investigate the possibility of their being used as substitution insulation material for

pavement. Cylindrical specimens with a diameter of 95 mm and a thickness of 50 mm

were cored from the RCPB. The sample was placed inside a thin cylindrical PVC sleeve,

into which it fits snugly. Each value represents the average of three samples.

Compressive strength was determined using a Universal Testing Machine with a maxi-

mum capacity up to 3000 kN. The load was applied to the nominal area of RCPB. Prior to

the loading test, the block was soft capped with two pieces of plywood on both ends to en-

sure a flat surface for testing to prevent point loading of the specimens. Average value of

compressive strength was calculated based on the five specimens (CMAA, 1996).

The abrasion index test was carried out in accordance with the (CMAA, 1996) method.

The test began by setting up the specimen under the ball-race; the ball-race was then lo-

wered down to the specimen surface and spun at the rate of 1000 revolutions per minute.

For every 1000 revolutions, penetration was measured by a dial-gauge. The test was con-

tinued until the ball-race had completed 5000 revolutions. The Abrasion index represents

the average value obtained from a set of five specimens.

The skid resistance of RCPB was determined using a British Pendulum Skid Resis-

tance Tester and it was expressed as the measured British Pendulum Number (BPN) as

specified by (ASTM E303, 1993). Prior to the testing, the surface of five samples RCPB

was cleaned and pendulum slider was positioned to barely come in contact with the dry

and wet test surface. The pendulum was raised to a locked position, and then released to

execute the first swing, but value was not recorded. Without delay, four more swings were

made, recording the results each time.

Impact test using falling weight methods design by (Ling, 2008) was used in this study.Impact test (a) was conducted by using a 3.76 kg falling weight dropped from a height of

up to 0.5 m, directly onto a RCPB sitting on a fixed steel plate. The loading face had a di-

ameter of 44.6 mm for the purpose of uniformly transferring the impact load to the RCPB.

Impact test (b) was to simulate the behaviour of a RCPB under loss of sub-grade support at

actual pavement structure. It was achieved by putting the block supported by two steel

rollers at a span set to 150 mm. Impact load was dropped from the centre of a unit block

until the block was broken into two halves. Two samples were tested and recorded for each

condition.


7/14


4. Results and Discussions

4.1. Properties of Fresh RCPB

Each batch of fresh RCPB produced was checked manually by sampling the specimens

from the pallet, looking for colour variations, both external and internal. Weight and di-

mensions of five sampling RCPB were checked in accordance to CMAA. Table 4 shows

the properties of fresh RCPB. The weight of fresh RCPB which decreases with the in-crease in the percentage of rubber content could be attributed by low specific gravity of

rubber particles. Moreover, an increase in rubber content increases the air content, which

in turn reduces the unit weight of the mixtures. This may be due to the non-polar nature of

rubber particles and their tendency to entrap air in their rough surfaces. Also when rubber

is added to a concrete mixture, it may attract air as it has the tendency to repel water, and

then air may adhere to the rubber particles.

Table 4: Properties of fresh RCPB

Mix nota-

tion

Depth

(mm)

Facing layer

(mm)

Weight

(kg)Visual Observations

T1 59.6 5.5 2.82 Very good, no cracking

T2 59.8 5.0 2.82 GoodT3 59.2 5.0 2.74 Some cracking

T4 59.8 3.3 2.68 Some cracking, delamination

4.2 Monitoring of dimensions and physical appearance

Any significant change in dimension indicated something awry in the parameters set-

ting during production.Therefore the height of fresh RCPB for each batch mixtures pro-

duction was checked and monitored by a height control device. After one day curing of

fresh RCPB, the physical attribute of hardened RCPB was checked again. The results of

the visual inspection of RCPB were no honeycombs, cracks or outstanding deformation

were found on T1 and T2 specimens. On the other hand, at a higher rubber content in

RCPB, cracks may appear on the facing layer and delamination between the layers. From

the test results, the total rejection rate of fresh and hardened RCPB specimens for T1, T2,T3 and T4 were approximately 5.3 %, 9.9 %, 12.4 % and 28.9 %, respectively. All the spe-

cimens that were rejected did not meet the CMAA requirement.

4.3. Surface Colour

Figure 4 shows the surface colours of the RCPB incorporating 20 % and 30 % crumb

rubber were slightly darker than RCPB incorporating 0 % and 10 % crumb rubber. This

slight coloration would not cause significant problem for pavement application.

Fig. 4. T1, T2, T3 and T4 specimens


8/14

8

4.4. Density, water absorption and voids

Figure 5 shows the relationship between the crumb rubber content with the water ab-

sorption values and voids of the RCPB. The increase of crumb rubber content from 10 %

to 30 % increased the water absorption by about 17 %. However for water absorption and

voids after immersion and boiling in the water, the control specimens showed higher val-

ues compared to the RCPB containing crumb rubber. This may be due to high level andproper compaction applied in commercial plant to RCPB containing crumb rubber, where

rubber particles help to fill and accelerate pores in concrete mixture (improve microstruc-

ture) because rubber particles are much softer (elastically deformable) than the surround-

ing particles.

Fig. 5. Relationship between crumb rubber content and water absorption

However, comparing the T2, T3 and T4, the adhesion between the crumb rubber and the

surrounding cement paste was affected significantly when the crumb rubber content keepsincreasing up to 20 % and above. This is because while plant machine applied a high com-

paction, crumb rubber would be compressed and after the compaction, the hydraulic ram

was released and the crumb rubber would return to the actual size resulting in micro cracks

and voids between the interfaces in concrete matrix. This resulted in more voids in RCPB

and tends to absorb more water.

It was found that there was a relationship between the crumb rubber content and density

of the RCPB as shown in Fig. 6. It was observed that, as the crumb rubber content keeps

increasing, this in turn reduced the apparent density, bulk density for dry, bulk density for

after immersion and bulk density for boil in the water. The incorporation crumb rubber up

to 30 % in RCPB reduced the (T4) density by 8.0 %, 8.3 %, 6.2 % and 7.3 % over the con-

trol specimens for the apparent density and bulk density for dry, after immersion and boil

in the water, respectively.


9/14


Fig. 6. Relationship between crumb rubber content and density

4.5. Acoustic properties

The results of sound absorption coefficients measured by the impedance tube method

are shown in Fig. 7. The results are calculated from three samples for dried-surface and

wet-surface conditions. In general, the RCPB containing crumb rubber was found to have

slightly higher sound absorption coefficients than control specimens over the entire fre-

quency range (1001600 Hz). This can be attributed to the fact that RCPB containing

crumb rubber contributes a higher porous surface layer and less density, resulting in lesser

frictional losses within the pore structure.

All RCPB including control specimens showed increasing sound absorption coefficients

as the frequency increased from 100 to 250 Hz. However, it then slows down as the fre-

quency keeps increasing, due to their specific characteristic of reflecting sound in the low

frequency range, but absorbing sound in the middle frequency range.At the same percentage of crumb rubber content, RCPB under surface-dried condition

has a markedly higher absorption coefficient than the surface-wetted condition. This can

be explained by the fact that the porous surface layer of surface-wetted RCPB is soaked

with water.

Fig. 7. Sound absorption coefficients of the RCPB


10/14

10

4.6. Relationship between compressive strength and abrasion resistance

The abrasion index and compressive strength of RCPB were determined at the age of 3,

7, 28, 91, 182 and 365 days. As may be seen from the plotted data in Fig. 8, it is possible

to establish a strong correlation between abrasion index and compressive strength. Gener-

ally, the abrasion index increased with the increase of compressive strength. This incre-

ment is primarily attributed to increase in curing age which resulted from the increasedmaturity of each RCPB. However the improvement of compressive strength was insignifi-

cant for T3 and T4 as compared to T1 and T2.

Fig. 8. Relationship between abrasion index and compressive strength

Therefore, comparing the rate of abrasion index, T3 and T4 were much higher than T1

and T2 which exhibited an increase in the abrasion index up to 104 % and 138 % as the

compressive strength kept increasing up to 21.92 MPa and 32.07 MPa, respectively.

The maximum abrasion index and compressive strength achieved for T1, T2, T3 and T4were (1.06, 60.41), (1.27, 64.68), (1.52, 32.07) and (1.14, 21.92), respectively. These re-

sults show that as the crumb rubber content increased in RCPB, it did not show any signif-

icant effect to abrasion index even though the rubber particles were weaker. This may be

attributed to the rubber particles on facing layer given a protection layer (which is elasti-

cally deformable) for RCPB to be abraded. Therefore, reasoning presented for rubber par-

ticles in RCPB may not be applicable for abrasion resistance of other types of material

mixed in CPB.

On the other hand, the amount of crumb rubber significantly affected the development

of compressive strength in RCPB. This could be attributed by stress concentrations of

higher volume crumb rubber content in RCPB. The strength may also be affected signifi-

cantly due to the loss of adhesion between the crumb rubber and the surrounding cement

paste.

4.7. Skid resistance

It was found that there is a good correlation between skid resistance and the crumb rub-

ber content in RCPB. As shown in Fig. 9, it is indicated that as the crumb rubber content

increased there was a decrease in the skid resistance. The crumb rubber appeared on the

facing layer decreases the contact area between the block surface and pendulum slider. In

addition, the smooth surface of the crumb rubber particles also affected the decrease in the

skid resistance.


11/14


Fig. 9. Relationship between skid resistance and rubber content under dried-surface andwet-surface condition

Furthermore, at the same replacement level, the BPN value under dried-surface condi-tion was higher than that of RCPB under wet condition. This is reasonable since the

wet/soaking appearance at the RCPB surface produced a more slippery surface texture,

thus reduced skid resistance. The decrement was higher at a high level of rubber content

(T4) over the low level of rubber content (T1), which accounted for a 13.7 % and 5.7 %

reduction in BPN, respectively. However, all control specimens and RCPB produced in

this study met the minimum requirement of ASTM.

4.8. Impact resistance

Table 5 shows the number of drops for causing damage by means of impact test (a) and

(b) on a set of RCPB. For impact test (a), it is found that the T1 without crumb rubber can

be easily broken into two halves at the 1st

drop (completely broken without any cracks be-

fore) and T2 was broken at the 4th drop (completely broken with cracks after three drops).

However, for the RCPB containing higher rubber content (T3 and T4), extra force was

needed to fully open the broken RCPB even after the 8th

and 9th

drops. This means that the

RCPB has a significant capability in absorbing dynamic load and in resisting crack propa-

gation.

Table 5. Number of drops for causing damage on a set of RCPB

Falling weight test RCPB

type

Small crack Transverse crack Completely broken

Sample 1 Sample 2 Sample 1 Sample 2 Sample 1 Sample 2

(a) Test on a fixed

steel plate

T1 - - - - 1 1

T2 2 2 3 3 6 4

T3 3 3 5 6 8 9

T4 4 4 6 6 10 9

(b) Test on two

steel rollers at a

span 150 mm

T1 - - - - 1 1

T2 - - - - 1 1

T3 - - 1 1 2 2

T4 - - 1 1 2 2


12/14

12

Comparing the RCPB under impact test (b), T3 and T4 also showed a better perfor-

mance in resistance to impact than T1 and T2. It can be explained by an observation that

after the 1st

central impact was achieved by means of falling weight, T3 and T4 specimens

were not fully broken into two halves under the loss of bottom support condition. The en-

hanced toughness can also be demonstrated by the effort required to fully open the RCPB.

The toughness is known as energy absorption capacity and is generally calculated from

the area under load-deflection curve up to where the point failure is plotted. Fig. 10 showsthe typical loaddeflection curve of T1, T2, T3 and T4. The figure indicated that as the

crumb rubber content increased, it increased the property of deformability and the maxi-

mum deflections. Even after the maximum applied load, it was observed that at a higher

crumb rubber content, RCPB was able to withstand and fail gradually. This means that the

samples were not completely fractured and could withstand post-failure loads with defor-

mations. From Fig. 11, it is also noticed that the energy absorption by RCPB (exhibit a

higher displacement at failure mode as rubber content increase) is much larger than that by

the conventional CPB.

Fig. 10. Loaddeflection curve of T1, T2, T3 and T4 specimens

Fig. 11. Failure patterns of T1, T2, T3 and T4 blocks: (a) plan view; (b) side view


13/14


5. Conclusions

This paper describes the potential use of recycled waste tyres (crumb rubber) as an ag-

gregate in RCPB production for pedestrian and trafficked pavement end user. Four differ-

ent percentages of crumb rubber including control mix were designed for RCPB produc-

tion by commercial plant equipment and conventional processes. It is found that there were

no complications when applying the mixtures to full-scale production in factory.Crumb rubber is a fine material with the gradation close to that of coarse sand. There-

fore replacement of sand is the most suitable choice than other particles in RCPB produc-

tion. The rubber particles are not as strong as basic items in CPB but have very high

toughness characteristic (elastically deformable). For this reason it is suggested that the

rubber substitution should not exceed 20 % in RCPB for trafficked pavement application.

The substitution amount of 10 % (T2) seemed more viable and provides higher strength

(because it is made under vibration and extreme pressure) and moderate toughness to the

RCPB which could be of great advantage to the environment and trafficked pavement ap-

plication. It is because RCPB will be more flexible and soft to the surface which provides a

better riding quality.

On the other hand, T3 and T4 with low strength and high toughness characteristics can

be introduced for specific purposes such as sidewalks and playground which do not requirea high strength RCPB and may be viable for other applications, depending on the percen-

tage of crumb rubber used. RCPB incorporating crumb rubber which was found to have

slightly higher sound absorption coefficients may resolve the noise generation problem

faced by conventional concrete block pavement. A series of laboratory accelerated loading

test was also carried out by the author and encouraging results on structural performance

of RCPB pavement were obtained (Ling et al, 2008).Therefore, RCPB products can be in-

troduced for varied paving application.

References

American Society of Testing and Materials. Standard Test Method for Measured Surface

Frictional Properties Using British Pendulum Tester. ASTM, 1993, ASTM E 303.

American Society of Testing and Materials. Standard Test Method for Impedance and Ab-

sorption of Acoustical Materials by Impedance Tube Method, ASTM, United State,

2004, ASTM C 384.

American Society of Testing and Materials. Standard Test Method for Density, Absorp-

tion, and Voids in Hardened Concrete. ASTM, United State, 2006, ASTM C 642.

Chan, D. & Poon, C. S. (2006). Using recycled construction waste as aggregate for pavingblocks.Magazine of Concrete Research159, No. 2, 8391.

Concrete Masonry Association of Australian. Specification for Concrete Segmental Paving

Units. CMAA, Australia, 1996, MA 20.

Fedroff, D., Ahmad, S. & Savas, B. Z. (1996). Mechanical properties of concrete withground waste tyre rubber. Transportation Research Record1532, 6672.

Hermandez-olivares, F., Barluenga, G., Bollati, M. & Witoszek, B. (2002). Static and dy-namic behavior of recycled tire rubber-filled concrete. Cement and Concrete Research

32, No. 10, 1587 1596.

Karasawa, A., Suda, S., Naito, H. and Fujiwara, N. Application of fly ash to concrete pav-

ing block. Proceedings of the 7th

international conference on concrete block paving,

Sun City, South Africa, 2003, pp. 343352.


14/14

Lam, C. S., Poon, C. S. & Chan, D. (2007). Enhancing the performance of pre-cast con-

crete blocks by incorporating waste glass ASR consideration. Cement and Concrete

Composites29, No. 8, 616625.

Li, G., Stubblefield, M. A., Garrick, G., Eggers, J., Abadie, C. & Huang, B. (2004). Devel-opment of waste tire modified concrete. Cement and Concrete Research34, No. 12,

22832289.

Ling, T. C. and Nor, H. M. Plant trial production process and monitoring crumb rubberconcrete paver. Proceedings of seminar kebangsaan penyelidikan kejuteraan awam.

Universiti Teknologi Malaysia, Malaysia, 2006, pp. 18.

Ling, T. C. and Nor, H. M. Properties of crumb rubber concrete paving blocks with andwithout facing layer. Proceeding of National Conference on Civil Engineering. Pulau

Langkawi, Malaysia, 2007, pp. 818823.

Ling, T. C. Engineering Properties and Structural Performance of Rubberized Concrete

Paving Blocks. PhD Thesis, Universiti Teknologi Malaysia, 2008.

Ling, T. C., Nor, H. M., Hainin, M. R. & Chik, A. A. (2008) Laboratory performance of

crumb rubber concrete block pavement.International Journal of Pavement Engineer-

ing, First Published on:30 September 2008.

Ling, T. C., Nor, H. M. & Hainin, M. R. (2009). Properties of concrete paving blocks in-

corporating crumb rubber and SBR latex. Road Materials and Pavement Design10,No. 1, 213222.

Naik, T. R. & Siddique, R. (2004). Properties of concrete containing scrap-tire rubber an

overview. Waste Management24, No. 6, 563569.

Nutalaya, S. Production of Low-Cost Pavement Concrete Blocks Using Mae-Moh Fly Ash.

M.Eng Thesis, Asian Institute of Technology, 1994.Phinyocheep, N. Structural Performance of Lightly Trafficked Flexible Pavements Using

Different Types of Interlocking Paving Blocks. M.Eng Thesis, Asian Institute of

Technology, 1988.

Poon, C. S., Kou, S. C. & Lam, L. (2002). Use of recycled aggregates in molded concretebricks and blocks. Construction and Building Materials16, No. 5, 281289.

Poon, C. S. & Chan, D. (2006). Paving blocks made with recycled concrete aggregate andcrushed clay brick. Construction and Building Materials20, No. 8, 569577.

Poon, C. S. & Cheung, E. (2007). NO removal efficiency of photocatalytic paving blocksprepared with recycled materials. Construction and Building Materials 21, No. 8,

17461753.

Poon, C. S. & Chan, D. (2007). Effects of contaminants on the properties of concrete pav-

ing blocks prepared with recycled concrete aggregates. Construction and Building

Materials21, No. 1, 164175.

Serumagard, J. S. and Blumenthal, M. Overview of scrap tyre management and markets inthe United States. 156

thACS rubber division meeting (Conference preprints), Orlando,

Florida, 1999.

Sukonrasukkul, P. & Chaikaew, C. (2006). Properties of concrete pedestrian block mixed

with crumb rubber. Construction and Building Materials20, No. 7, 450457.Toutanji, H. A. (1996). The use of rubber tire particles in concrete to replace mineral ag-

gregates. Cement and Concrete Composites18, No. 2, 135139.

Documents

Using Recycled Waste Tyre in Concrete Paving Blocks