Swelling Behavior of the Expansive Soil Prepared with Calcium Bentonite

The swelling and shrinkage characteristics of expansive soil caused by changes in water content are expressed in the form of downward settlement and lifting of the lightly loaded structures such as pavements, roadways, foundations, reservoirs and channels. In this study, an artificially prepared expansive soil by the use of calcium bentonite has been used for evaluating the swelling pressure and its effect on the lightly loaded structure (single-story residential building). The expansive was prepared by adding different percentages of calcium bentonite (10, 15 and 20%) to the natural soil collected from the trench surrounding Aligarh Fort. Swelling pressures were obtained based on constant volume method. On the basis of experimental observations, it is concluded that as the percentage of calcium bentonite increases, the properties such as free swell value, swelling pressure, consistency limits and optimum moisture content increase, while the maximum dry density decreases. Free swell and swelling pressure were increased from 14 to 29% and 40% to 50%, respectively.