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Tung-Chai Ling

Postdoctoral Fellow, Hong Kong

Polytechnic University, Kowloon,

Hong Kong

Hasanan Md. Nor

Professor, Universiti Teknologi

Malaysia, Johor, Malaysia

Siong-Kang Lim

Assistant Professor, Universiti

Tunku Abdul Rahman, Selangor,

Malaysia

Proceedings of the Institution of

Civil Engineers

Waste and Resource Management

163

February 2010 Issue WR1

Pages 3745

doi: 10.1680/warm.2010.163.1.37

Paper 800029

Received 14/10/2008

Accepted 08/07/2009

Keywords: materials technology/

recycling & reuse of materials/

strength and testing of materials

Using recycled waste tyres in concrete paving blocks

T. C. Ling MEng, PhD, H. M. Nor MSc, PhD, PGradDip and S. K. Lim MEng, PhD

There is general agreement that waste tyres should be

better managed in order to preserve valuable resources

and prevent environmental damage as a result of

improper disposal. This paper describes the use of crumb

rubber in concrete paving blocks. Existing block material

is characterised as a composite with high compressive

strength but with low toughness; the addition of rubber

improves toughness while meeting minimum strengthrequirements. A total of 4300 rubberised concrete paving

blocks were produced in a commercial plant, and 348

were tested for compression and abrasion performance,

sound absorption, voids and skid resistance. The test

results revealed that rubber substitution should not

exceed 20% by sand volume in order to avoid excessive

reductions in compressive strength. Further investigations

showed that sound absorption and toughness were

improved as the rubber content in the mix increased. The

specimens showed a significant capability for absorbing

dynamic loading and resisting crack propagation, which is

beneficial for pavements that require good impact

resistance properties.

1. INTRODUCTION

Industrial by-products or solid wastes that would otherwise be

discarded as harmful environmental pollutants are being widely

used as cement or aggregate replacements in concrete, and ways

of using waste materials in civil engineering applications are

increasingly being sought. One example is the use of industry

by-products and solid wastes in highway construction.

In some Asian countries such as Hong Kong, Japan and Thailand,

waste management has become an acute problem with rapid

increases in urbanisation and economic development leading to

larger quantities of waste materials requiring proper management.

Generally, solid wastes are disposed of in landfills, but waste

minimisation, reuse, material recycling and energy recovery are

being encouraged.

In order to promote such initiatives, a number of research studies

have investigated the use of industrial by-products and solid

wastes in the production of concrete paving block (CPBs). The

construction industry in Hong Kong generates huge amounts of

solid waste such as crushed clay brick, crushed ceramic tile,

crushed waste glass and wood chips. Numerous studies on the

application of construction and demolition (C&D) wastes as fine

and coarse aggregate materials (e.g. Chan and Poon, 2006; Lam

et al., 2007; Poon and Chan, 2006, 2007; Poon and Cheung, 2007;

Poon et al., 2002) have indicated the possibility of utilising huge

amounts of C&D wastes in concrete. The use of recycled

aggregates in CPB production has been successfully implemented

and is gaining wider acceptance. In addition to the environmental

benefits of reducing the amount of solid waste sent to landfill,

utilisation of such wastes also preserves the natural materials that

would otherwise have been used in concrete production.

In recent years, the amount of coal ash produced by Japanese

power plants has reached about 27 000 t/day (Karasawa et al.,

2003). Fly ash can be used as a substitute for fine aggregate in the

production of CPB, but only if the fly ash replacement ratio is

25%. Nutalaya (1994) and Phinyocheep (1998) cite a large amount

of literature on the applications of fly ash in CPB production. It is

estimated that about 45 000 t of fly ash lignite is consumed every

day at the 2025MW Mae-Moh power plant in Thailand, and

Nutalaya (1994) studied the possibility of using the fly ash in the

production of low-cost CPBs. Apart from the environmental

benefits, such a scheme would provide employment for the low-

income communities living in the vicinity of the power plant.

2. RESEARCH BACKGROUND

One of the most common global environmental issues is the

management of scrap tyres, which are not readily biodegradable

(Figure 1). Every year, approximately 800 million new tyres are

produced in every region of the world (Serumagard and

Blumenthal, 1999). Although the lifetimes of some tyres have been

prolonged, ultimately they will all be discarded as waste. The

majority of tyres end up in already congested landfills, becoming

mosquito breeding places, or are burnt. The melting tyres produce

large quantities of oil, which contributes to the contamination of

soil and ground water.

Recent statistics in Malaysia indicate that the number of

registered vehicles has doubled over the past ten years (Ling

et al., 2009b). With 13 million vehicles in Malaysia at present, a

very large number of scrap tyres are produced every year. The

Department of the Environment has banned the open burning

and burying of waste tyres in order to reduce air pollution and

land instability. Even though several agencies and municipal

councils are involved, they often have no clear direction in

relation to waste management. Only a few companies utilise

shredding to produce crumb rubber and rubber powder (the cost

of crumb rubber is about RM 1000/t (RM 3.51 US$)). There is

therefore a clear need to seek and identify economic and

Waste and Resource Management 163 Issue WR1 Using recycled waste tyres in concrete paving blocks Ling et al. 37