SOIL STABILIZATION WITH GEOPOLYMERS FOR LOW COST AND ENVIRONMENTALLY FRIENDLY CONSTRUCTION

Abstract

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.