Influence of gypsification on engineering behavior of expansive clay

Volume change in argillaceous sediments can take place due to either swelli ng of expansive clay or gypsification of anhydrous calcium sulfate. Gypsifi cation offers a variety of serious geotechnical hazards such as high swell pressure, Boor heave in tunnels, massive rock uplift in dams, and damages t o light structures and pavements. Some of these phenomena have been observe d in the Arabian Gulf coastal region, where the behavior of local argillace ous sediments is controlled by severe climatic and environmental conditions . Based on laboratory investigation of natural and synthetic samples, this paper studies the influence of gypsification of anhydrite on the engineerin g behavior of calcareous expansive clay.