Black cotton soil is a typical expansive soil which loses its strength in presence of water résultant in swelling of the soil and in absence of water it shows multiple cracks due to shrinkage. Present paper 

describes the strength behaviour of Black cotton soil treated with calcium chloride (CaCl2). From the immediate compaction and unconfined compressive strength test up to 30 days of curing, it was observed that Black Cotton Soil with 3% CaCl2 (by weight of soil) combination found to be optimum percentage. Direct shear test was conducted under soaked condition with various curing periods, Safe Bearing Capacity determined as per IS codal practice. In this paper an approach is also made to give a comparison of improvement in factor of safety of the black cotton soil treated with calcium chloride with black cotton soil alone. It is found that addition of 3% calcium chloride has shown higher factor of safety with higher curing periods for an embankment slope of 1:2.5.