Compressive, flexural and corrosion permeability resistance properties of concrete with bauxite tailing as supplementary mineral admixtures

Abstract

This paper investigates the compressive and flexural properties and corrosion permeability resistance of concrete, using bauxite tailing as supplementary mineral admixtures. The concrete mixes, curing and testing for mechanical properties were conducted in accordance with BS EN 12390, 2019. Chloride permeability test was conducted in accordance with ASTMC 1202, 1997. The results depicted that at the optimum composition of 20% replacement, the compressive strength, flexural strength and static modulus of elasticity increased by 22%, 28% and 13% respectively over the control concrete specimen. These results showed that, generally, there was an increase in the strength properties and subsequently the modulus of elasticity when cement was replaced with bauxite tailing at the latter age. Again the presence of silicate and aluminum in the bauxite tailing might have consumed Ca(OH)2 which was liberated from cement hydration, enriching the microstructure of the concrete (AS2 +3CH+6H=C2ASH8 +C-S-H) with C-S-H gel and crystalline calcium alumino-silicate (C2ASH8) at the latter age than at the earlier age. The mixes with bauxite tailing replacement had low permeability and very low chloride penetration as compared to the control concrete specimen. This study recommends that bauxite tailing should be used as a mineral admixture to concrete not exceeding 20% replacement and in a chloride environment.