Effect of Combined Sulfate-Chloride Attack on Concrete Durability - A Review

Chloride and sulfate ions damage the reinforced concrete in marine environment due to the corrosion and formation of expansive products, respectively. Interaction of chloride-sulfate ions on concrete deterioration is very complicated. Little research has been conducted in this respect. In this study, the effect of chloride ions on sulfate attack and effect of sulfate ions on chloride attack were reviewed. According to the results, contradictory reports were observed in studies. However, most of the researchers believed that chloride ions mitigate the sulfate attack in combined chloride- sulfate solutions. On the other hand, regarding the influence of sulfate ions on chloride attack, some of the researchers reported the mitigating effect, but others referred to the accelerating effect. Tricalcium aluminate (C3A) content, water to cement ratio (w/c), duration of submerging, corrosive ions concentrations, cation type, type of pozzolan and its replacement are important parameters that could affect the concrete performance against combined chloride-sulfate solution.