Mechanical properties of alkali-activated mortar in organic acid environment

Ingression of acid into the concrete results in early degradation by microstructural alteration of phases leading to mass changes, weakening of mechanical properties and increase in porosity due to calcium leaching. This paper discusses the resistance of geopolymer composites (GP) and conventional concrete system (OPC) in 0.125M and 0.25M concentrations of acetic acid medium by investigating the changes in the mechanical properties of mortar. The results of the study reveal that the GP samples display increased resistance to acetic acid attack not only in terms of mass and strength loss but also with reference to the variation in ultrasonic pulse velocity and relative dynamic modulus of elasticity. The results also manifest that blends of ground granulated blast furnace slag (GGBS) and fly ash (class F) (FA) with red mud (RM) offer increased acid resistance due to the nature of the main binder gel produced in GP systems.