Experimental study of natural soil stabilization with geopolymer based on glass powder and carbide calcium

Environmental, economic, technical issues and the limitation of energy resources and raw materials in the cement production process create the necessity of using cement substitutes, for this purpose three types of soil, namely sand with different ratios of silt or natural soil (Sx), soil cement stabilized (CSS), and geopolymer stabilized soil based on glass powder and calcium carbide (GSS) have been studied mechanically and dynamically. The strength, shear modulus and damping of the samples were studied under unconfined compressive strength (UCS) and cyclic triaxial tests under all-sided pressures and different shear strains and silt ratios of 10%, 25% and 50%. Different mixing plan of geopolymer materials for UCS test was prepared and the optimal proportion of mixing plan in which the resulting geopolymer includes the highest compressive strength of the soil was determined as the optimal geopolymer. Optimum geopolymer composite proportions in terms of maximum strength were obtained, consisting of 15% glass powder, 7% calcium carbide and 25% silt, which concentrations more/less than the optimum value reduce the compressive strength. The optimal compressive strength of soil-geopolymer was about 16% higher than that of cement-stabilized soil of 4%. Increasing the confining stress improves the shear modulus at small strains, while having little effect on the damping ratio. The compressive strength, hardness and shear modulus of geopolymeric soil was higher than that of cement soil. Shear resistance and damping of soils with different ratios of fine grain increases up to a certain level of threshold fine grain (50% silt).