Influence of the microstructure properties on the degradation of concrete submitted to external sulphate attacks

The study presented in this paper is aimed at developing experimental and numerical tools to assess performances of concrete exposed to sulphate attacks. The experimental test is applied to mortars in order to compare different binders. It consists in immersing mortar specimens in sodium sulphate solution and monitoring mass, expansion and elastic modulus. It showed significant differences between low and high C3A cements and between Portland and blended cements. On the other hand, simulations based on a finite difference model and homogenization methods have been performed and compared to experiments. Results are sensitive to the degree of hydration of cement phases and microstructure properties. It showed that this approach is able to take into account changes in chemical composition of the binder and of the mortar mixtures