Utilization of fly ash and lime to stabilize the expansive soil and to sustain pollution free environment – An experimental study

Abstract Expansive soils are problematic due to the performances of their clay constituent usually have the potential to show their undesirable engineering properties such as low bearing capacity, high shrinkage and swell characteristics. The shrink-swell behaviour makes the soil inappropriate for direct engineering application in its natural form and in order to enhance its engineering quality to make them more feasible for usage, stabilization soil can be done physically or chemically. Soil stabilization has been practiced for quite some time by adding mixtures. An experimental investigation was conducted to study the individual and combined effects admixtures viz., lime and fly ash on the geotechnical characteristics of expansive soil. First, expansive soil is mixed with 4% and 8% of lime and next expansive soil is mixed with 10% Fly ash + 4% Lime and 10% Fly ash + 8% Lime. The result shows that addition of expansive soil with lime alone or with lime and fly ash in different percentages, the liquid limit, plastic limit and plasticity Index, optimum moisture content and differential free swell index decreased, whereas maximum dry unit weight and strength of soil admixtures increased. Flocculated structure with voids filled by admixtures resulting in decrement of plasticity characteristics, optimum moisture content and differential free swell index and increment in maximum dry unit weight thereby strength of soil-admixtures compared to soil alone.