EVALUATION OF TECHNIQUES FOR THE PREVENTION OF STEEL CORROSION IN REINFORCED CONCRETE IN AGGRESSIVE ENVIRONMENT

Abstract

The purpose of this study was to evaluate the influence of cement type, concrete cover and addition of migratory corrosion inhibitor (MCI) on the corrosion resistance of reinforced concrete subjected to aggressive environment. For this, corrosion tests were performed using CP IV RS and CP II F cements with two levels of concrete cover: 2.5 cm and 4 cm. In the thinner one, the migrating corrosion inhibitor was added. In the research the techniques used were: determination of concrete compressive strength, electrode potential measurements, acceleration cycles of chloride attack and visual analysis. The results showed that both the cement type and the migratory corrosion inhibitor contributed to the inhibition of steel corrosion. In concretes with inhibitor and thinner cover the most extreme measurements were verified: in the 14th weekly cycle the concrete with CP II F cement presented a potential of -366 mV, characterizing 90% of probability of corrosion, while the one with CP IV RS showed a potential of -119 mV, with a corrosion probability of less than 10%. However, following the cycles, it was possible to identify an increase in the value of this potential. The influence of the concrete cover thickness was also observed, since the potential values found were more negative in the cases of smaller covers.