Geopolymer coating as a protection of concrete against chemical attack and corrosion

In order to mitigate and prevent chemical attack and concrete corrosion one has to choose the right concrete to make it less permeable or isolate it from the corrosive environment by using a suitable coating. Here, we present the use of geopolymer mortar made of local waste materials and sodium silicate as a chemo-resistive coating for concrete. In this paper, the development of geopolymer mortar working parameters (e.g. setting time and adhesion to concrete) is described. Here, we investigated the resistance of concrete samples coated with geopolymer to 10% inorganic/organic acids and saturated solution of sodium chloride. During the soaking in corrosive environment, weight loss and compressive strength were measured. Geopolymer coating described in this work showed great resistance to organic and inorganic acids. Coating of concrete samples reduced their weight loss after exposure to organic acids from 15% to 2% with concomitant compressive strength loss from 49% to 9% of the initial value. The difference in chemical resistance for inorganic acids was even more visible. Coating of concrete samples reduced their weight loss after exposure to inorganic acids from 73% to 0.8% with adequate compressive strength loss from 96% to only 3.5% of the initial value