This paper presents the effects of using a small percentage of cement to stabilize clayey silt with a low organic content. Cement was added at percentages of 1, 2, 4 and 7% by dry weight. The physical and mechanical properties of the treated and untreated soil were evaluated by laboratory tests including tests of consistency limits, unconfined compressive strength, soil density, solidification and pH values. These tests have been conducted after 7, 14, 28, 60 and 90 days of curing time. Workability is defined as how easily the soil can be control or to handle physically. Results showed that the engineering properties of the clayey silt were improved. The soil exhibited better workability directly after treatment, and the workability increased with time. Soil density increased, while water content decreased, with increasing cement content and longer curing time. The pH value was immediately raised to 12 after adding 7% cement content, and then it gradually decreased as curing time increased. An increase of unconfined compressive strength and stiffness was observed, while strain at failure decreased. A gradual change in failure mode from ductile behavior to brittle failure was observed. The findings are useful when there is a need for modification and stabilization of clayey silt in order to increase the possibilities for different use which will reduce transportation and excavation.
Keywords: Stabilization, small amounts, cement, secant modulus, workability, solidification, pH value.