عنوان مقاله [English]
Portland cement is one of the most common materials for improving the mechanical properties of soils; however, it has a lot of detrimental effects on the environment. Cement production releases million tons of carbon dioxide gas (CO2) to the air and uses million tons of raw material such as clay and limestone. For this purpose, geotechnical engineers are looking forward to using a new friendly environment material instead of cement. Geopolymers are new alternative materials that have some advantage such as high resistance, friendly environment, long durability, and low cost. Two materials need to make a geopolymer matrix. First, any materials have silicate and Aluminium oxide and Second Alkaline activators. In this study, a geopolymer based on rice husk ash and iron ore tailings (IOT) are used for sandy soil stabilization. Two types of alkaline activators are used: 1) Type I sodium hydroxide and 2) Type II carbide calcium residue. Various parameters such as type of material consumed, percentage of compound composition, type of alkaline activator, and processing time are considered as influencing factors in the behavior of the stabilized specimens. Unconfined Compressive Strength (UCS) and splitting tensile strength tests (Brazilian test) are the main criteria for a comparison of the specimens to evaluate the effect of a geopolymer on the mechanical behavior of the specimens. X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses are performed to investigate the microstructures of the stabilized soil. The results show that by adding the optimum amount of additives and handling the specimens under ambient conditions, the unconfined compressive strength of the specimens increased. The optimum percentage of selected specimens is a combination of 10% of rice husk ash and 24% of iron ore tailings for activator I and 18% of iron ore tailings for activator II. The use of type I activator indicates that it is highly effective in the formation of aluminosilicate gels in geopolymer compounds.