Abstract

This study investigates the possibility of using high sulphate resisting cement as an additive to control the compressibility behavior of two saline soils sourced brought from Baghdad and Basra governorates in Iraq. The two soils are similar in their constituents, and classified as CL according to Atterberg limit. Standard consolidation samples were prepared from untreated soils, and were treated with 3, 5, 7, and 10% cement by weight and cured for 7, 14, and 21 days. The soil samples were then socked in water and standard consolidation tests were performed on them. Chemical and mineralogical analyses were also carried out before and after the different treatments. The tests results revealed that high sulphate resisting cement successfully influenced the compressibility behavior of both soils. It was observed that the curing period played a major role in reducing the compressibility. Our results also showed that 14 days curing was sufficient for the completion of the major reactions between the cement and the saline soil. The addition of 3% cement by weight to both soils was sufficient to reduce the compression index, C_c, by about 50 to 60% after of 7 days curing. In general both soils exhibited further decrease in the compression index with increasing cement content and curing period. The reduction in compressibility of the treated soils was also accompanied by substantial increase in the modulus of elasticity.

Key words: Compressibility, saline soil, sulphate resisting cement, cement treatment, Iraq.