Effect of Fly Ash on Strength and Swelling Aspect of an Expansive Soil

Expansive soils pose serious challenges to lightly loaded structures due to swelling, shrinkage, and uneven settlement caused by moisture variation. This study investigates the stabilization of such soils using fly ash. Laboratory tests were conducted to compare the index, compaction, and strength properties of natural and fly ash–stabilized soils. Parameters like liquid limit, plastic limit, shrinkage limit, grain size distribution, swelling potential, maximum dry density, and optimum moisture content were evaluated. Unconfined Compression and California Bearing Ratio tests were also performed. The results indicate that adding an optimum percentage of fly ash effectively reduces swelling potential and improves strength, demonstrating its suitability for expansive soil stabilization.