Improvment of expansive soil using indusrial wastes

Expansive soils present significant geotechnical and structural engineering challenges the world over, with costs associated with expansive behavior estimated to run into several billion annually. Expansive soils are soils that experience significant volume change associated with changes in water contents. These volume changes can either in the form of swell or in the form shrinkage.The idea of using recycled materials in construction applications is not a new concept. Reports on this subject can be found dating back to the 1970?s. In this study, lignin, wire plastic, rice husk powder (RHP), rice husk ash (RHA) and tire ash (TA) were used for stabilization of expansive soils. The expansive soil is prepared in laboratory as a mixture of red clay and Bentonite. Lignin, wire plastic and rice husk powder were added to the expansive soil with percentage of stabilizer varying from 0 to 20 percent by mass, and different quantities of rice husk ash and tire ash from 0 to 10% by mass were added to expansive soil. Atterberg limits,swelling percentage and unconfined compressive strength were determined for the samples.It was found that all samples except the 20% lignin treated sample show a decrease in liquid limit and plastic index. Also, Swelling percentage decreased with increasing wire plastic, RHP and RHA percentages, while up to10% lignin and 5% TA swelling percent was decreased. Further increased of lignin and TA (10%lignin and 5%TA) was found to be the optimum with regard to swelling percent.It was found that lignin, RHP, RHA and curing duration had a significant positive influence on the unconfined compressive strength of the clay.Keywords: Soil Stabilization, Expansive Soil, Swelling, Waste Materials.