Effect of binary mixtures on chloride induced corrosion of rebars in concrete

Rebar corrosion is one of the most important phenomena affecting the durability of reinforced concrete structures. Corrosion inhibitors can be used as a preventative method, able to delay corrosion, or as repair method, to reduce corrosion rate. During more than 15 years in our laboratories an intense experimental research was carried out: the aim of the research was to identify new organic substances or mixtures thereof that might have inhibiting effectiveness. In the paper the effect of binary mixtures on chloride induced corrosion of rebars in concrete is studied; the mixtures are based on two amines, dimethylethanolamine (DMEA) and triethylenetetramine (TETA), and a carboxylate (benzoate); the tests were carried out for comparison purpose also in concrete containing nitrite, acknowledged to be the most effective product. The best results among the binary mixtures were shown by the benzoate-TETA, while the mixtures based on DMEA-TETA were not satisfactory. The performance of the mixtures is not comparable to nitrites.