Influence of Organic Inhibitors on the Corrosion Behavior of Steel Rebar insideMortar Specimens Immersed in Saturated NaCl Solution

The long. term effects of four kinds of amine. alcohol based inhibitors on the corrosion behavior of steel rebar inside mortar specimens immersed in saturated NaCl solution were studied by electrochemical impendence spectroscopy (EIS), half cell corrosion potential (E(corr)), and macrocell corrosion current density (I(corr)) measurements. We found that the E(corr) and the impedance modulus were higher than those in the control specimen after inhibitor addition. Additionally, I(corr) decreased over the initial 100 d of immersion revealing that the steel rebar electrodes are kept in passive state and the inhibitors showed good inhibition effects. With an increase in the immersion time, E(corr) and the impedance modulus for all the inhibited mortar specimens decreased while I(corr) increased. After immersion for 125 d there were no obvious differences between E(corr) and I(corr) for the inhibited systems by comparison to those in the blank sample, except for the specimen containing CI-4. This suggests that the surface of the electrode changes from passive state to active state. The best inhibition was obtained in the presence of the CI-4 inhibitor. We briefly discuss the inhibition mechanism based on the competitive adsorption of the inhibitor molecules with Cl(-) on the steel rebar surface.