Mechanisms of Sulfate Attack in Plain and Blended Cements: A Review

The recent modifications in the physicochemical characteristics of Portland cements and the extensive use of mineral admixtures have introduced significant changes in the chemical and mineralogical composition in the present day cements that need to be addressed by the construction industry. Moreover, the effect of cation associated with the sulfate ions on these changes is inconclusive and highly debated in the concrete literature. In addition, the exposure of many reinforced concrete structures to sulfate-bearing environments has focussed attention on the role of sulfate ions in the corrosion of reinforcing steel. In view of the above-cited controversies, this paper presents a state-of-the-art review on sulfate attack in plain and blended cements from a civil engineering perspective. In particular, the paper addresses the following subjects: (i) mechanisms of sulfate attack in plain and blended cements; (ii) factors affecting sulfate attack; (iii) modes of deterioration; (iv) effect of sulfate cation type on the strength and expansion of plain and blended cements; (v) effect of sulfateions on the weight loss and reinforcement corrosion of reinforced concrete specimens; (vi) role of chloride ions in sulfate attack in plain and blended cements; and (vii) protection of the concrete structures exposed to sulfate-bearing environments.