Strength Properties of Slag Cement Stabilized Kaolinite

Due to low strength and high compressibility, soft clay should be improved to increase its strength, stiffness and durability, and decrease the permeability and the ground settlement for a better construction condition. Nowadays the sustainability is much more important, so recycled materials such as fly ash and slag have been widely used in soft ground improvement. Through replacing part of the cement, the slag-cement material could provide a lighter weight and lower hydration heat. In this research, the soft clay defined as kaolinite with high water content was mixed with slag-cement. In this thesis, a series of unconfined compression tests were carried out on the slag-cement stabilized clay. The specimens were prepared under three different initial water contents, ωi = 1.8LL, 2.0LL, 2.2LL, and five different cement content, C/S = 15%, 20%, 25%, 50%, 75%. All specimens were stored in a saturated environment to be cured for 3, 7, 14, 28, and 56 days before testing. The variation of the unit weight could be controlled within 1.5%, and the variation of the duplicated tests was also compared in this research. Therefore, the quality control of the specimens could be understood clearly. The results showed that the unconfined compressive strength increases when the curing time increases. It also indicated that the higher the slag-cement content, the greater strength and stiffness of the improved clay. Based on the test results, slag-cement is an effective, economic and environment friendly additive for soft ground improvement.