This paper presents experimental data on a remoulded expansive soil stabilised with calcium carbide residue (CCR) and class-C fly ash (FA) which are waste products respectively from acetylene gas and power plants. This paper attempts to estimate the optimal CCR content and the optimal CCR + FA ratio from different contents of CCR and different proportions of CCR and FA used in order to improve the soil. The expansive soil had an FSI of 140%, which indicated high degree of expansion. The tests carried out were free swell index (FSI), Standard Proctor compaction, unconfined compression test (UCS) and California bearing ratio (CBR) using various proportions of CCR and FA. The UCS samples were tested at the curing periods of 7, 14, 21, 28 days. It was observed that the soil blended with 6% CCR indicated the maximum 28-day strength. Further, UCS tests were conducted on the blends of the soil and 8% CCR stabilised with varied FA contents (0, 5, 10, 15 and 20%). 10% FA content blended with the soil-8% CCR mixes resulted in the highest UCS at 28 days. CBR tests were also carried out on soil-CCR blends after soaking the samples for 3 days. As 8% CCR was observed to be the optimum content, CBR tests are conducted on the soil-CCR blends stabilized by varied FA contents. CBR was also found to be the highest at 10% FA. Hence, 6% CCR when used alone, and 8% CCR and 10% FA when used as a combination, can be considered as optimum contents.