Laboratory investigation of liquefaction mitigation in sand using zeolite-cement injection

The study on liquefaction mitigation using cement-based materials in soils with liquefaction potential is of great interest. As cement production is a costly and environmentally polluting process, replacing part of it with environmentally friendly and cheaper materials such as natural zeolite is very important and attractive. In the present study, to evaluate the improvement of the liquefaction resistance in loose sand using zeolite-cement injection, a series of triaxial tests was performed. Also, the liquefaction potential of injected specimens was investigated based on the results of bender element, unconfined compressive strength and monotonic triaxial tests. The results of the study indicated that the injection of tested sand with zeolite-cement grout is significantly effective in liquefaction mitigation of the sand. Even under very strong earthquakes, liquefaction did not occur in the injected specimens with water to cementitious materials' ratio (W/CM) of 3 and a cement replacement with zeolite (Z) up to 70 %. The optimum amount of zeolite (Z_opt) corresponding to the maximum liquefaction resistance was 30 %. It was shown that, considering the optimization of energy consumption as well as environmental considerations, for earthquakes with a CSR ≤ 0.2, by grout injection with Z₉₀ and W/CM of 5, the used sand liquefaction resistance is more than double. For more severe earthquakes (CSR ≤ 0.3), injection with a grout containing Z₇₀ and W/CM of 7 resulted in no liquefaction. To counteract the liquefaction under very strong earthquakes (CSR_0.5), grout injection with Z₅₀ and W/CM of 5 can be effective.