SOIL STABILIZATION WITH GEOPOLYMERS FOR LOW COST AND ENVIRONMENTALLY FRIENDLY CONSTRUCTION

In this paper, a geopolymer synthetized from olivine and an alkaline solution made from sodium hydroxide which incorporates the carbonation process was utilized to stabilize silty clay soil, in order to improve its expediency for different cases of construction. The effect of alkaline molarity, for alkali activation and carbonation processes, on the Unconfined Compression Strength (UCS) of the soil-olivine mixture is important in enhancing the treated soil properties. In this study, the use of 4, 6, 8, 10, and 12 molars of NaOH affected the UCS and toughness of the soil mixture. The highest strengths were obtained at 8 and 10 molarities for the carbonated alkali activation process, and 10 and 12 molarities for the alkali activation process only. Micro structural analysis using X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests show the benefits of carbonation in terms of decreasing the molarity of alkaline agent. This was due to the crystallization processes which accounts for strength gain after carbonation. This paper highlights a more environmentally friendly procedure of stabilizing soils compared with the traditional binders such as cement and lime.