Strength Amplification of Expansive Soil Using Phosphogypsum

Abstract

This research highlights the effectiveness of phosphogypsum in reducing the expansive nature of A-6 soil, presenting a promising path for long-term and cost-effective soil stabilisation procedures in civil engineering applications.This paper includes a thorough analysis into the usage of phosphogypsum as a soil stabilisation material for A-6 soil, which is classified as expansive and problematic by AASHTO. The study looks at how different percentages of phosphogypsum (3%, 6%, 9%, 12%, and 15%) affect many critical soil parameters, including Atterberg’s limits, compaction, hydraulic conductivity and CBR. The experimental results reveal that phosphogypsum greatly enhances soil properties. The liquid limit decreased from 69% to 58%, but the plastic limit climbed slightly from 25.17% to 25.94%. As a result, the plastic index improved, and the optimal moisture level increased from 10.4 to 11.4. The maximum dry density dropped from 1820 kg/m³ to 1500 kg/m³. The hydraulic conductivity of soil fell from 9.67E-07 cm/s to 5.7E-07 cm/s. The California Bearing Ratio (CBR) values also improved, rising from 4.61% to 7.95%.