Passivating action of an organic inhibitor on the steel of reinforced concrete

Abstract

An electrochemical evaluation has been made on a concrete mix with an organic inhibitor added, in order to establish its contribution to the formation of a protective film on the steel surface. Concrete cylinders (6″ × 3″), each with a 3/8″ steel bar and two graphite electrodes embedded, with two water/cement ratios (0.40 and 0.55) were used as testing samples. Reinforced steel bars, both chemically cleaned and in the as rolled condition, embedded in salted and unsalted concrete mixes, were used to test if chemical adsorption occurs in each condition. Samples were soaked into brine solution during 365 days as to simulate a sea environment. During exposure period readings of potential, corrosion rate and potentiodynamical cyclic curves were made. It can be concluded that the organic inhibitor needs a low water/cement ratio mix (0.40) in order to react via a chemical adsorption on the steel, being more effective on cleaned surfaces.