Durability performance of a lime stabilized expansive soil with egg shell ash as a subsidiary admixture

Stabilization is broadly classified as mechanical and chemical stabilization. Lime stabilization is the most commonly adopted method for stabilising expansive soils. In recent years, lime has been combined with other waste materials for improved performance in stabilization. One such waste is egg shell waste, generated by the poultry industry. Calcination of egg shell waste results in the formation of egg shell ash (ESA) which has a chemical composition very similar to that of quick lime. This investigation focuses on the potential of ESA as an auxiliary additive for lime in the stabilization of expansive soils. The initial consumption of lime of the expansive soil was determined using the Eades and Grim pH test. The lime content in the stabilization process was modified with ESA up to 0.5% in increments of 0.1%. Unconfined compression strength test samples of dimensions 38 mm x 76 mm were cast and cured for a period of 21 days and tested for their strength. The durability of the samples was also evaluated by subjecting the samples to 1, 4, 7, and 10 cycles of wetting and drying. The results of the investigation revealed that 0.2% ESA was the optimal dosage of additive to lime stabilization for improved performance.