The effectiveness of Ca (NO2) 2 and NaNO2 as a corrosion inhibitor has been confirmed. However, it may be important from the viewpoint of corrosion of reinforcement in the concrete contaminated with Cl- ion to reveal the behavior of NO2- ion in relation to Cl- ion concentration in pore solutions in concrete. In this study, the analyses of pore solution in NaCl containing-mortars with and without inhibitor were carried out to elucidate effects of the inhibitors on the chloride binding capacity of mortars. NO2- ion concentrations in the pore solution in NaCl-containing mortars treated with 1% Ca (NO2) 2 by mass of cement were lower than in the corresponding mortars with NaNO2. The addition of NaNO2 a little raised OH- ion concentration, but OH- ion concentration was reduced in the mortars containing Ca (NO2) 2. However, Cl-/NO2- ratio in the pore solutions in mortars containing Ca (NO2) 2 were lower than in mortars containing NaNO2 because of the dissipation of greater amounts of Cl- ions from the pore solutions in the former than in the latter.
