Experimental Study on the Effect of Using Geopolymer and Recycled Tire Fibers on the Strength of Fine-Grained Soils

Portland cement production, the most widely used material in the construction industry, is associated with high energy consumption and environmental pollution. Therefore, the use of alternative stabilizing materials such as geopolymer is proposed to introduce sustainable and environmentally friendly methods for soil improvement. In this study, volcanic ash was used as the base material for geopolymer stabilization. Additionally, the effect of waste tire fibers as a complementary reinforcement agent was investigated. For this purpose, soil samples were improved using weight percentages of volcanic ash ranging from 0 to 15% and tire thread fibers ranging from 0 to 1.5%. The effects of time and curing conditions on the unconfined compressive strength (UCS) and shear strength parameters of the samples were investigated. Based on the results, it was found that the UCS of the samples increased under dry curing conditions and with increasing curing time. Moreover, the geopolymer stabilized samples performed better than those cured under optimum moisture conditions. The results of the direct shear tests showed an increase in the shear strength of the improved samples under saturated conditions.