Effect of Wet-Dry Cycle on the Void Ratio of Expansive Yazoo Clay

The Yazoo clay is dominant in the central Mississippi and neighboring states. This clay consists of very expansive characteristics and undergoes volumetric changes due to wetting or drying under different seasonal variations. Even though the Yazoo clay causes significant problems to the infrastructures in the southern states of the United States, limited research has been conducted to date on the volumetric changes of the Yazoo clay. This study investigates the change in the void ratio of Yazoo clay under a series of wet and dry cycles. Reconstituted Yazoo clay specimens were used for the experiment. The samples were subjected to 3, 5, and 7 number of wetting and drying cycles in an enclosed chamber for 24 hours period. During the drying process, the temperature ranged from 120–125 deg. F to simulate the typical high summer temperature of Mississippi. The axial deformation of the samples, as well as the change in void ratios at each cycle, were closely monitored. The test results indicated that the void ratio increases with the increase of wet and dry cycles and causes an overall reduction in the shear strength.