An investigation on the effect of lime addition on UCS of Indian black cotton soil

Abstract

The study’s objective is to determine the optimum content of lime added to Indian black cotton soil to improve the soil’s unconfined compressive strength (UCS). The lime was added to the black cotton soil in varying proportions of 3%, 6%, 9% and 12% of the dry weight of the soil. The engineering properties of weak black cotton soil (BCS) were determined experimentally according to Indian Standard specifications. It was found that the soil under test consisted mainly of silt 75.60% and clay 18.80%. The laboratory testing showed that the value of maximum dry density (MDD) increases from 1.605 gm/cc to 1.693 gm/cc and the UCS value increased from 50.2 kN/m2 to 90.6 kN/m2 with 9% addition of lime content and for 28 days of curing time. The UCS of soil–lime mix decreased drastically beyond 9% addition of lime, showing that the optimum value of lime content to strengthen the weak soil is 9%. The strengthening of black cotton soil with the addition of lime as an additive provides stability to the civil engineering structures like sub-base/subgrade for roads and other engineering projects.