This research work presents the efficacy of Calcium chloride and fly ash as an additive in improving the engineering properties of Black cotton soil which is expansive soil. Calcium chloride of 1%, 2% and 3% were mixed with black cotton soil used in the laboratory experiments. The fly ash percentages of 20% and 30% were used for compare the results obtained with calcium chloride percentages. The effectiveness of the calcium chloride and fly ash tested by conducting unconfined compressive strength and swelling pressure test. The unconfined compressive test has done for curing period of 7, 14, and 28 days to compare the results with 0 days unconfined compressive strength. The soil samples were subjected to wet and dry cycles and observed that increase of unconfined compressive strength and reduction of swelling pressure. The results were obtained from calcium chloride mixes soil sample after wet and dry cycles has better strength, less swelling pressure and less swelling inde
