Model tests on the use of tyre chips as aggregate in stone columns

Large-scale beneficial use of recycled and waste materials for civil engineering applications can provide an attractive way to reduce the wastes to be disposed of and it may also provide fiscal benefits. Scrap tyres are one such waste material which has many properties that can be effectively utilised for civil engineering applications. In this study, the scope for using tyre chips as an aggregate for stone columns was investigated. Experiments were conducted using tyre chips 10 mm in size and stone aggregate passing through a 12·5 mm Indian standard (IS) sieve and retained on a 10 mm IS sieve. Fifteen model experiments were carried out on stone columns made of different mix proportions of stone aggregate (S) and tyre chips (T), in a kaolinite clay bed of uniform consistency. It was found that the mixtures 60%T + 40%S and 40%T + 60%S provided a load-carrying capacity in stone columns similar to the load-carrying capacity of stone column made using only stone aggregate (100%S). This clearly shows that waste tyre chips can be used as a partial replacement for stone aggregate up to about 40–60% in the construction of stone columns.