Evaluation of the damaged depths of slag-based mortars in aggressive sulphate conditions

Abstract

Resistance of cement composites against various chemical processes such as sulphate attack and corrosion is nowadays one of the most desired property. Mechanism largely involved in sulphate corrosion is the ingress of aggressive ions through diffusion. The result of the ingress of aggressive ions is leaching of the elements from the mortar matrix and the deterioration of the composite. In the experiment, the slag-based cement mortars samples were exposed to an aggressive microbiological sulphate environment, represented by the bacteria A. thiooxidans, for the period of 6 months. The paper presents the investigation of damaged depths of cement mortars based on the leaching characteristics of the Ca ions. The damage depths (EDD) of cement composites were much higher (up to 0.2 mm) for samples placed in the biotic environment, which confirms the aggressive action of A. thiooxidans.