A Study on the Swelling Behaviour of Black Cotton Soil with Fly Ash, Lime and Coconut Husk.

This paper presents the results of a laboratory study undertaken to investigate the effect of fly ash, lime and coconut husk on the index properties of black-cotton soil. The black-cotton soil has a poor supporting capacity and large change in volume on variations of moisture content. Such expansive soils may need to be improved to make them suitable for construction activities. To investigate the effect of fly ash, lime and coconut husk on index properties of black-cotton soil a series of laboratory experiments have been conducted on black-cotton soil samples mixed with 0% to 20% of fly ash, lime and coconut husk by weight of dry soil. The test results showed a significant change in consistency limits of samples containing fly ash, lime and coconut husk. The liquid limit would decrease from 57.67% to 38 %. The plasticity index decreased from 28.35% to 19.85 % and shrinkage limit increased from 8.00% to 19.39% with the addition of fly ash, lime and coconut husk from 0% to 20% of the dry weight of the black-cotton soil. Also the differential free swell decreased from 63.15% to 23.0%, showing appreciable decrease in swelling behaviour.