Index Properties of Marginal Clay Soils Treated with Sawdust Ash and Cement

Abstract

This research endeavours to evaluate the efficacy of incorporating marginal lateritic soil with ordinary Portland cement (OPC) and Sawdust Ash (SDA) for soil stabilization, considering the exorbitant cost and environmental detriments associated with industrialized stabilizing agents (such as cement, lime, and bitumen) during their production. The soil utilized in this study was procured from a borrow pit situated along Bauchi-Gombe Road, in the Inkil town of Bauchi Local Government Area, Bauchi state, Nigeria. The soil falls under the A-7-6(28) classification by the American Association of State Highway and Transport Officials (AASHTO), and the CH classification by the Unified Soil Classification Systems (USCS). Various concentrations of ordinary Portland cement (OPC) and Sawdust Ash (SDA), ranging from 0% to 9% and 0% to 10%, respectively, based on the dry weight of the soil, were blended. Specific gravity, particle size distribution, and Atterberg limit tests were conducted on both the natural and treated soil samples. The liquid limit steadily decreased from 61.7% for the natural soil to 30.1% at a composition of 6% OPC and 6% SDA. The plastic limit increased from 26.8% for the natural soil to 15.2% under the 6% OPC and 6% SDA treatment. Consequently, the plasticity index decreased from its initial value of 34.9% for the natural soil to 9.9% at the 6% OPC and 6% SDA composition. Notably, these proportions align with the stipulated requirements for liquid limit, which should not exceed 50%, and plasticity index, which should not surpass 30%, as applicable to roadway construction and engineered waste containment facilities.