The potential use of recycled tyre rubber in concrete under impact loading

Abstract

Being a small island, limited space for landfilling is available, therefore waste must to be turned into a resource. The construction industry is one of the main industries in our islands, and one that affects our environment most. New legislation by the European Union prohibits landfilling of both whole and shredded tyres. This dissertation focuses on the replacement of natural aggregate by tyre rubber shreds, and sand by crumb rubber, and testing of rubberized concrete under impact loading. Seven different mixes, with different percentages of rubber replacement, together with a control mix were prepared. Amongst these mixes, two were tested after seven days and the remaining at 28 days. There is no recognized standard for impact testing, therefore an impact rig, and an impact test procedure had to be designed. The test procedure and impact rig were designed on the basis an ACI publication (Atef Badr and Ashraf F. Ashour (2005) ACI materials journal (v.102, No.4, July-August 2005 pp249-254.)) All mixes exhibited higher impact resistance than the control samples, both at 7 and at 28 days. Mixes consisting of tyre shreds demonstrated better impact resistance compared to mixes consisting only of crumb rubber replacement. On the other hand, the mix, consisting of both tyre rubber shreds and crumb rubber, and tested after 7 days, exhibited higher performance when compared to the mix consisting only of 25% tyre shred replacement and tested after 28 days. The results show the validity of using scrap tyre rubber in concrete under impact loading. Further tests must be carried out in order to test the validity of this material as a building component in the construction industry.