Experimental Study on the Corrosion Rate of Rebars in Chloride-Contaminated Concrete with Adding or Painting Inhibitors

Tests were conducted to investigate the inhibiting effect on steel bars in concrete contaminated with 0.75% (wt.) chloride of the cementitious materials by adding inhibitor in green concrete or surface painting inhabitor on cover concrete. The results show that the anticorrosion effect of surface painting inhibitor on concrete with 30mm cover at 400g.m-2 are mainly better than that of adding 2% inhibitors in concrete with 0.75%(wt.) NaCl of the cementitious materials. The minimum corrosion current of steel bar in concrete sample after painting MCI-C12 28 days can be reduced to 0.084 μA.cm-2 from 1.30 μA.cm-2 of the sample before painting inhibitor. The corrosion current of steel bars in concrete samples painted with MCI-2010 and sodium nitrite solution are roughly equal to that of the control concrete sample without chloride, and less than that of the sample added in nitrite and chloride. Compared with mixed inhibitor in green concrete, surface applied inhibitor on hardened concrete not only avoid to affect the properties of concrete, but also bring to the visible economical advantage.