The use of recycled waste tyre rubber in concrete

Abstract

One of the mam wastes generated in the engineering and transportation sector is tyres. Nowadays, due to new legislation, the only way one can dispose of such waste is either through material or energy recovery. Locally, although we make use of material recovery through granulation, very few uses are given to this material; the majority of it is exported to other countries since land filling is prohibited. Locally, one of the largest industries is the construction industry. Concrete is a widely used material, however, due to the countries' limited land, quarries for aggregate are becoming problematic. Utilising the waste tyres generated annually and combining them with concrete would not only increase the quarries' lifetime hut convert a continuously growing prohlem into an opportunity. This investigation aims to utilise shredded ruhher chips and crumb rubber in concrete replacing coarse and fine aggregate respectively. For this purpose, ten mixes were done, one control mix and nine rubberised concrete mixes. From these nine mixes, four contain shredded rubber chips, another three mixes contain crumb rubber, and two mixes contain both shredded rubber chips and crumb rubber. Compressive and flexural tensile strength tests were carried out on different samples from each mix, at 7 and 28 days to determine the perfonrnmce of the concrete in their hardened state. Although all rubberised concrete exhibited lower compressive and flexural strength than the control mix, the mixes containing the shredded rubber chips exhibited very good overall results both in its fresh and hardened state when compared to similar studies conducted abroad. Results show great potential in further exploring shredded rubber chips in concrete whereas the potential use of crumb rubber in concrete would be possible if one overcomes the issue of bonding between the rubber and the cement paste.