Effect of Mineral-Stabilized Black Cotton Soil Subgrade on Flexible Pavement Analysis and Design

Being one of the most expansive soils, black cotton soil is not considered as a foundation material for any civil engineering infrastructure. However, due to the unavailability of good soil, the researchers and practitioners are motivated to identify methodologies to improve the engineering properties of black cotton soil for its use in civil engineering construction. Among the various possible methods of ground improvement, soil stabilization is chosen by a majority of engineers due to its multitude of advantages. In this direction, the research study investigates the effect of mineral-stabilized black cotton soil on flexible pavement analysis and design. To achieve the objective, black cotton soil was stabilized at various percentages of mineral stabilizers at 0, 2, 4, and 6%, and the engineering properties of the stabilized soil were determined from the laboratory studies, including, standard proctor, unconfined compressive strength, and California bearing ratio. At the optimum stabilizer dosage derived from laboratory studies, pavement analysis using the Plaxis 3D software was carried out to understand the improvement in the mechanistic behavior of mineral-stabilized soil. Further, pavement design in accordance with IRC 37:2018 was performed to quantify the reduction in overall pavement thickness with subgrade stabilization. The results showcased that the stabilization of black cotton soil with mineral stabilizer significantly enhanced the engineering properties of the soil and thus resulted in a better-performing pavement structure with reduced construction cost. Overall, it can be concluded that the mineral stabilization of black cotton soil is a promising solution for pavement subgrade improvement.