LABORATORY STUDY ON THE SOIL STABILIZATION OF EXPANSIVE SOILS USING QUICK LIME

Abstract

Expansive soils, commonly found in arid and semi-arid regions, present significant challenges to civil engineering due to their tendency to undergo substantial volume changes with variations in moisture content. These soils are prone to swelling during wet seasons and shrinking during dry seasons, leading to differential settlements and structural damage. This study investigates the effectiveness of lime stabilization in enhancing the engineering properties of expansive clay soils. Laboratory experiments were carried out to evaluate the impact of varying lime content on Atterberg limits, unconfined compressive strength (UCS), and swelling potential. Quicklime was mixed with the expansive soil at varying percentages (2%, 4%, 6%, and 8% by dry weight), and specimens were cured for 7, 14, and 28 days. The untreated soil exhibited a liquid limit of 68%, plastic limit of 36%, and a plasticity index (PI) of 32%, which indicates high plasticity. With 6% lime content, the PI reduced to 18%, showing a significant decrease in soil plasticity. The swelling potential dropped from 12.5% in the natural soil to 2.1% with 6% lime treatment, indicating a major improvement in volume stability. Unconfined compressive strength tests revealed that the UCS of untreated soil was 120 kPa, while the strength increased to 460 kPa with 8% lime after 28 days of curing. The optimal improvement in strength and reduction in swell potential were observed at 6% lime content, beyond which the gains became marginal. These results demonstrate that lime effectively modifies the physicochemical properties of expansive soils, making them suitable for use as subgrade and foundation materials. In conclusion, lime stabilization is a proven, economical, and environmentally sustainable method for improving the performance of expansive soils in geotechnical and pavement engineering applications.