Experimental study on unconfined compressive and cyclic triaxial test behavior of agar biopolymer–treated silty sand

Abstract

The need for space for infrastructure development has plummeted studies in ground improvement to an eminent research topic. But in the present day where the need for sustainability is of utmost importance, efficient and environment-friendly improvement methods have been coming up among which the use of biopolymers as a soil additive have gained popularity. In the current research, various strength aspects of agar biopolymer–treated silty sand soil have been explored. The unconfined compressive strength property of treated silty sand at varying agar dosages (0.5%, 1%, and 2%) at different curing periods (3 days, 7 days, and 28 days) was analyzed using laboratory investigations. Furthermore, the effect of frequency of loading on dynamic properties and pore pressure response of the agar-treated silty sand was also investigated by performing a set of strain-controlled cyclic triaxial test at different frequencies (0.2 Hz, 1 Hz, 1.5 Hz, and 2 Hz). The tests were performed at constant axial strain amplitude of 1% and at confining pressure of 100 kPa. The results demonstrated that with the increase in agar content and curing time, the unconfined compressive strength of soil also increased. Besides, a decrease in pore pressure build-up, decrease in secant shear modulus, and an increase in damping was observed on increasing the frequency of cyclic loading.