Experimental Investigation and Performance Evaluation of Lithomargic Clay Stabilized with Granulated Blast Furnace Slag and Calcium Chloride

Abstract

South-western coast of India has vast deposits of highly problematic silty soil normally referred to as lithomargic clay in the literature. This problematic silty soil is characterized by its high sensitivity to moisture content with high erosion potential and low shear strength. This paper attempts to address this problem by chemical stabilization of lithomargic clay using Calcium chloride (CaCl<inf>2</inf>) and an industrial by-product obtained from the iron industry, i.e., granulated blast furnace slag (GBFS). Disposing of huge quantities of GBFS poses a severe impact on the environment. GBFS has high pozzolanic activity, and utilizing it for the stabilization of soils would be a sustainable and eco-friendly solution. To optimize CaCl<inf>2</inf> and GBFS contents for achieving better geotechnical properties of the stabilized soil and to understand the mechanism governing the improvement, a series of laboratory experiments were performed on lithomargic clay by stabilizing it with different amounts of CaCl<inf>2</inf> and GBFS. Optimum CaCl<inf>2</inf> and GBFS contents obtained from the laboratory experiments are 6% and 20%, respectively, and a significant increase in strength was achieved with this optimized mix. Scanning electron microscope and X-ray diffraction analyses were carried out on the powdered samples of the treated soil, and the improvement in strength was justified through the microstructural changes observed due to the formation of cementitious compounds. Response of strip footings lying on unstabilized, and stabilized soils was analyzed using PLAXIS-2D. Numerical simulations showed a significant increase in the allowable bearing pressure with stabilization of lithomargic clay with GBFS and CaCl<inf>2</inf>. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.