Effect of Curing Time and Confining Pressure on the Mechanical Properties of Cement-Treated Sand

摘要

Cement-mixing has recently been one of the popular ground improvement technologies in geotechnical engineering practice. It is gaining more acceptances in ground improvement techniques due to its improved sustainability, strength and deformation characteristics. In order to design effectively the behavior of cement-mixed sand needs to be well understood. Similar to concrete materials, hydration of cement in cement-mixed soil continues with time, thereby improving the strength and deformation characteristics of cement-mixed soil over time. On the other hand, the molding water content, compaction energy level, cement to sand ratio affects significantly the stress-strain characteristics of cement-mixed soil. However, the confining stress has also the effect on the strength and deformation characteristics of soil which has not been considered in the case of cement-mixed sand. The objective of this study is to investigate the coupled effect of curing period and confining stress on the strength and deformation characteristics of cement-mixed sand. A series of consolidated drained (CD) triaxial tests were performed with two different curing periods and for each curing period, they were sheared under three different confining stresses in the triaxial test to observe the effect of confining stress. Cyclic loading and bender element test were also performed at certain intervals during triaxial test to determine the Small strain stiffness parameters, Young's modulus (E0) and shear modulus (Gvh) values. The results show that the curing time has a significant effect on the peak strength, stiffness and modulus values. The confining stress has also effect on the peak strength, stiffness and shear modulus values. However, the effect of confining stress on the elastic modulus is not very clear.