Corrosion inhibitors for chlorides induced corrosion in reinforced concrete structures

Reinforcements corrosion is the most important cause of premature failure on reinforced concrete structures. Phenomena promoting corrosion are the ingress of chlorides and the reaction of atmospheric CO2 with cement paste. Aim of this paper is the investigation on the effectiveness of three organic commercial inhibitors in preventing carbon steel chlorides induced corrosion in concrete, since there is not yet a clear knowledge on the real effectiveness of these products. Inhibitors were added to the concrete mixture in dosage suggested by the manufacturers. Chlorides were added in the concrete mixture or penetrated from outside by ‘‘ponding’’ cycles with a 3.5% sodium chloride solution. The effectiveness of the inhibitors has been evaluated by long-term rebar corrosion monitoring in reinforced concrete and by rebar visual inspection after three years tests. Also solution tests were performed in order to verify the effectiveness of inhibition. Results give information about corrosion prevention ability of analysed commercial inhibitors.