Corrosion inhibitors in reinforced concrete structures. Part 2: repair system

The results presented in the present paper concern the effectiveness of commercial migrating organic inhibitors for the corrosion of steel reinforcement in concrete. Four series of concrete specimens were cast to verify the ability of the inhibitor to delay, reduce or stop corrosion, both in chloride contaminated concrete (adding chlorides to the concrete mixture or allowing them to penetrate the concrete) and in carbonated concrete. Two organic migrating inhibitors (amine- and alkanolamine based) were applied on the surface of concrete following the manufacturers’ recommendations. The free corrosion potential and corrosion rate of the steel reinforcing bars were periodically monitored for more than four years. The results show that migrating inhibitors are not effective in reducing the corrosion rate, either for chloride- or carbonation induced corrosion, although some effect was observed on delaying the initiation of corrosion in the case of chloride penetration. Further investigations will be performed in order to evaluate the extent and depth of corrosion (following the destructive removal of the steel from concrete), and to estimate the depth of penetration of the migrating inhibitors.