Stabilization of Black Cotton Soil With Sand and Cement as a Subgrade for Pavement

Expansive soil (Black cotton soil) is very weak and does not have enough stability for any type of construction work. In pavement, subgrade layer is the bottommost layer underlying the base course or surface course. To make the subgrade soil stable, by improving its engineering properties is very essential. In the present work, stabilization of subgrade soil by using sand and cement (varying percentage of sand and constant percentage of cement by weight of soil) is used to enhance the strength of subgrade soil. The purpose of this study is to determine the optimum dose of the stabilizer, which improves the strength of soil (CBR less than or equal to 2% to more than 7%) which is suitable for pavement structure. To evaluate the strength of soil, various test have been performed such as sieve analysis, liquid limit, Plastic limit, Standard proctor test and CBR test in the laboratory. The result shows that the use of sand and cement in combination, increases the California Bearing Ratio values (CBR) i.e. the strength of soil to a great extent.