Resistance of fly ash geopolymer binders to organic acids

Abstract

AbstractFly ash geopolymers are a relatively new class of binders with the potential to reduce the CO2 emissions associated with Portland cement based construction materials. This paper reports on the organic acid resistance of fly ash geopolymers following exposure to acetic and lactic acid. Organic acids are prevalent in many circumstances including agriculture, production processes and waste management. These findings demonstrate that the surface of fly ash geopolymers had superior resistance to organic acids when compared with traditional Portland cement, evidenced by smaller mass losses. This was attributed to the formation of reaction products which were less susceptible to acid attack than those formed in Portland cement systems due to their lower calcium content. However, despite the surface of fly ash geopolymers appearing less deteriorated due to organic acid attack, they were found to have a higher porosity than their Portland cement counterparts making them more susceptible to acid ingress.