Effect of NaNO₂and C₆H₁₅NO₃Synergistic Admixtures on Steel-Rebar Corrosion in Concrete Immersed in Aggressive Environments

This paper studies effect of different combinations of NaNO 2 (sodium nitrite) and C 6 H 15 NO 3 (triethanolamine (TEA)), as synergistic admixtures in concrete immersed in NaCl and in H 2 SO 4 test environments, on the corrosion of the concrete reinforcing steel (rebar). Although statistically analysed electrochemical test results confirmed NaNO 2 effectiveness, synergistic combinations of 4 g NaNO 2 + 4 g C 6 H 15 NO 3 in NaCl medium and of 2 g NaNO 2 + 6 g C 6 H 15 NO 3 in H 2 SO 4 medium were also highly effective at inhibiting rebar corrosion. Synergistic parameter analyses showed that the effective synergistic admixtures that inhibited concrete steel-rebar corrosion in their respective medium were the NaNO 2 and C 6 H 15 NO 3 combinations that exhibited synergistic interactions of cooperative adsorption on steel-rebar. These support the suitability of requisite concentration of triethanolamine as additive admixture with sodium nitrite for steel-rebar corrosion mitigation, which is potent with reduced environmental effects, in concrete immersed in NaCl and in H 2 SO 4 corrosive media.