Evaluation of Compressibility and Drainage Characteristics of Highly Plastic Clay Stabilized with Fly Ash and Stone Quarry Dust

Approximately, one-fifth parts of the soil deposit in India is covered with high compressible clay (i.e., Black cotton soil); due to high volume change behavior on changing moisture and poor drainage condition, such soil is classified as problematic soil and requires suitable modification before using it as a soil support. In this study, fly ash and stone quarry dust were used as stabilizing admixture to improve the mechanical behavior of soil, which reduce the waste disposal problem and the environmental pollution, and save the natural material (soil). Here, soil sample was collected from SH 102, B.P. Road, Allahabad and classified as CH. Fly ash was collected from Prayagraj Thermal Power Plant, Bara Allahabad (660 MW), and stone quarry dust was obtained from Shankargarh crushing unit, Allahabad. Three different types of samples were prepared in which soil was mixed with fly ash, stone quarry dust, and both in equal proportion in different percentages (i.e., 4, 8, 12, 16, 20, 25, and 30%) by dry mass separately. After proper mixing and aging of samples, standard consolidation test was carried out on each sample. The calculated values of compressibility characteristics (c_c, c_v) and permeability (k) have reflected considerable and justified results, in which coefficient of compressibility decreasing, coefficient of consolidation, and permeability increase with increasing mix proportion of differently used admixtures with different rates. The optimum percentages for all three different mixes have been determined and compared by considering a triple bottom line of the sustainability.