Subgrade Black Cotton Soil Stabilization using Ground Granulated Blast-Furnace Slag (GGBS) and Lime, an inorganic mineral

The rapid growth of population and fast urbanization has resulted in the reduction of the good quality of available land. Black cotton (BC) soil is one of such problematic soils, though they are very fertile soils, they are not suitable for the foundation of roads and buildings. They are expansive clays with a high potential for shrinking or swelling as a result of changing moisture content. Due to the intensive shrink-swell process, surface cracks appear during dry seasons. A small amount of rainfall, such as 6mm can make these soils impassable for all traffic. About 23% of the area in India is covered by BC soil. To utilize expansive soils effectively, proper ground improvement techniques are to be adopted. One of the most widely used technique is to stabilize the expansive soil with conventional admixtures like lime, Ground granulated blast-furnace slag (GGBS), cement, and fly ash. Lime is an inorganic mineral that primarily contains calcium oxide and calcium hydroxide. GGBS is a by-product produced in blast furnaces used to make iron (mineral). In the present study, an attempt is made to modify the engineering properties of black cotton soil. This research work presents the improvement of engineering characteristics of expansive soils using lime and GGBS as an additive. For experimental work, lime of 2%, 4%, and 6% is used, and corresponding 5%, and 10% of GGBS is used. Tests like the California bearing ratio test, unconfined compression test, proctor test, Atterberg’s limits were performed. After stabilization, it was found that the unconfined compression strength and California bearing ratio of soil increased significantly.