EFFECT OF SURFACE APPLIED CORROSION INHIBITORS ON THE DURABILITY OF REINFORCED SELF-COMPACTION CONCRETE CONTAMINATED WITH CHLORIDE

In recent years, migratory corrosion inhibitors (MCIs) have been used as the coating agents for rehabilitating the chloride-contaminated reinforced concrete structure. In this paper, studies have been carried out to investigate the inhibiting effectiveness and the migratory performance of amino alcohol (AMA) and amine carboxylate based MCIs in self-compaction concrete contaminated with chloride ion. The harden reinforced concrete specimens (C60) contaminated with 0.5% NaCl by mass of the cementitious materials in the mixing process were experienced 15 wet-dry cycles until the initialization of steel corrosion were estimated. The specimens were subjected to more than five months exposure tests after painting with 400 g/m(2) MCIs. The corrosion behavior of the steel rebar in specimens was monitored using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and corrosion currents. The results indicate that after surface painting the MCIs 150d the reinforcements in concrete samples showed an average corrosion rate of 0.279 mu A/cm(2) compared with the average corrosion 2.37 mu A/cm(2) of samples before painting. The minimum corrosion current of sample coating with 4# inhibitor can be reduced to 6.47% of the sample before painting. The higher organic nitrogen content in 30-40mm, depth and XPS analysis indicate the inhibitors migrate through the concrete capillary and micro-crack to the surface of steel bars in cover concrete. The results showed that the MCIs was effective in suppressing corrosion development or rehabilitating the corrosive steel bar when they were applied on the surface of the hardened concrete.