Effect of drying and wetting on strength of lime-stabilized clays

An experimental investigation of lime stabilization of clays and its influence on such engineering properties as plasticity and moisture-density relation are reported. The effect of drying and wetting on the unconfined compressive strength of two lime-stabilized clay soils with different plasticity indices, was investigated. The percentages of hydrated lime used were 0, 3 and 6, by dry weight of soil. Specimens were compacted at optimum moisture content, wrapped in aluminum foil, sealed with paraffin, cured for 5 days at 120°F and then soaked in water for 4 days prior to strength testing. The prepared lime-clay specimens were subjected to cycles of drying and wetting prior to strength determination. Unconfined compressive strength tests were performed at the end of 0 to 8 cycles of drying and wetting. The drying temperature of the wetting-drying cycles, was varied as 75°F, 120°F and 140°F for similar samples. Results showed that the strength of clay soils was greatly increased by the addition of lime (after a curing period), but that a large decrease in strength was suffered when exposed to drying and wetting. The reduction in strength was generally less pronounced for samples with higher lime content, under lower number of cycles of drying and wetting, and at the lower drying temperature. The specimens when dried at 120°F and 140°F, showed visible distortion and disintegrated after 3 cycles of drying and wetting, at most.