Effect of binder chemistry on sulphate resistance of fly-ash blended cement concrete mixes

Abstract

The chemical durability of concretes exposed to sulphate environment largely depends on the quality and quantity of products of cement hydration. Certain hydration products are readily reactive with the sulphate ions and form expansive products such as gypsum and ettringite. On the other hand, some sulphate compounds participate in reducing the cementing property of hydration products. These reactions cause expansion and deterioration of strength of concrete. Sulphate resistance of concrete can be improved by the incorporation of Supplementary Cementitious Materials (SCMs). Reduced water-binder ratio and proper curing can make concrete more durable in sulphate environment. This paper reports the details and results of an investigation of effect of chemical composition of binder materials on the sulphate resisting property of concrete exposed to a rich MgSO4 solution. The effect of initial curing is also investigated so that it may be possible to suggest the mix compositions for typical field applications of concrete. The variables investigated in this report are the oxide composition of binder components and the initial curing conditions. A set of concrete mixes, all with a constant binder content and water-binder ratio are used in the investigation. © 2020 Published under licence by IOP Publishing Ltd.