Performance Evaluation of Black Cotton Soil Stabilized with Boxedum Sand and Red Mud

Black cotton expansive soil commonly referred to in the region as regur soil, has a high shrink-swell behavior which causes structural failures and foundation instability. The research paper examines the efficacy of red mud, which is the by-product of alumina smelting and boxedum sand, which is a waste accomplished by refractory industry, in regulating regur soil gathered in ChitturTaluk, Palakkad District, Kerala. The stabilization process was carried in red mud,boxedum sand combined with the native soil at different proportions (15 percent and 20 percent by weight). Specific gravity, Atterberg limits, unconfined compressive strength (UCC) and permeability, compaction and California Bearing Ratio (CBR) were subject of the laboratory investigations which were carried out according to IS 2720 standard requirements. Besides that, Scanning Electron Microscopy (SEM) was also conducted to examine the microstructural changes and bonding properties of stabilized soil. Some findings shown showed that cohesion and interlocking of particles were increased by the introduction of red mud which was fine and alkaline, whereas the boxedum sand particles served as a filler to enhance density and gradation. The ideal mixture that included red mud 10 percent and boxedum sand 10 percent showed increase in UCC strength, CBR value and plasticity index by 35,40, and 25 percent respect accordingly in comparison to untreated soil. Stronger correction of the samples proved through SEM images that the stabilized samples were packed denser and the particles bonded better. The paper concludes that red mud and boxedum sand could be successfully used in improving the geotechnical characteristics of regur soil, to offer less expensive and environmental friendly alternatives to stabilization of subgrades and foundations.