Stabilization and Solidification of a Clay Soil Contaminated with MTBE

This paper presents an investigation into stabilization and solidification of a clay soil contaminated with methyl butyl ether (MTBE) using two different agents (cement and a mixture of bentonite and cement) through a program of laboratory experiments. The samples were prepared in two stages. In the first stage, they were prepared with 20 and 30% cement, but in the second stage they were prepared with 20 and 30% mixtures of bentonite and cement (with ratios of bentonite to cement equal to 1∶1 and 3∶1). Unconfined compression tests (UCT) and leaching tests using a gas chromatography (GC) apparatus were conducted on the samples prepared in the described two stages at different curing times. The results show that by using cement, the strength of the soil is increased. The results of the leaching tests on contaminated soil show a major reduction in the concentration of MTBE. Adding cement to contaminated soil causes a reduction in the concentration of MTBE, but by increasing the curing time, the concentration of MTBE is increased. It is also indicated that using a combination of bentonite and cement leads to reductions in MTBE concentration, and the amount of reduction is decreased by increasing the curing time. A bentonite to cement ratio of 3∶1 is more effective than 1∶1 in reducing the concentration of MTBE.