Chloride adsorption of synthetic individual reaction products in alkali-activated fly ash

Compared to ordinary Portland cement, reaction products in alkali-activated fly ash (AAF) exhibit different characteristics, dramatically influencing their chloride adsorption ability. This paper extensively characterized the chloride adsorption behavior of individual reaction products in AAF. First individual reaction products, including NASH gels, P zeolite and analcite, were synthesized and their composition, morphology and structure were extensively evaluated. The chloride adsorption ability of the above synthetic reaction products was then investigated. The synthetic reaction products mainly physically adsorbed chlorides on their surface. When Si/Al ratio of NASH gel increased, its chloride adsorption ability was enhanced, which was mainly related to the positive shift of zeta potential. The synthetic P zeolite and analcite exhibited lower zeta potential and specific surface area, thus their chloride adsorption ability was lower than synthetic NASH gels.