Published Paper Details:

Black cotton soil, a widely occurring expansive clay in India, poses serious challenges for road construction due to its high swelling and shrinkage potential, low bearing capacity, and poor stability under varying moisture conditions. Such problematic soil conditions lead to premature pavement failures, particularly in low-volume rural roads where economical solutions are essential. This study focuses on improving the engineering properties of black cotton soil by stabilizing it with a combination of fibres (polypropylene and coir) and industrial by-products (RBI Grade-81 and ground granulated blast furnace slag - GGBS). A comprehensive experimental program was undertaken to evaluate index properties, compaction characteristics, unconfined compressive strength (UCS), California Bearing Ratio (CBR), and static and cyclic plate load behaviour of the untreated and treated soils. The results revealed that the combined use of RBI Grade-81 with polypropylene fibre significantly enhanced strength, ductility, and stiffness modulus compared to other stabilizers, while GGBS showed progressive strength improvement with curing. Overall, the treated soil exhibited substantial gains in CBR values, enabling a reduction of pavement thickness by up to 50% for low-volume road applications. The findings highlight that blending fibres with chemical and industrial stabilizers offers a cost-effective and sustainable solution for enhancing the performance of black cotton soil in rural infrastructure development.