Effectiveness Protection Performance of an Internal Blending Organic Corrosion Inhibitor for Carbon Steel in Chloride Contaminated Simulated Concrete Pore Solution

Application of corrosion inhibitors is considered as one of the most economical and effective solutions for the protection of reinforced concrete structures under severe environment. The aim of this paper is to investigate the protection performance and mechanism of an internal blending organic inhibitor for carbon steel in chloride contaminated simulated concrete pore solution. The influences of concentration of inhibitor, chloride content and pH value of the solutions on the protection efficiency were investigated. Both weight loss and electrochemical were used to evaluate the protection efficiency of the inhibitor. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) analyses were performed to reveal the mechanism of corrosion resistance of the inhibitor. Results indicated that the corrosion of carbon steel in chloride contaminated simulated concrete pore solution was highly resisted in presence of inhibitor, the inhibition efficiency of 3.5% NaCl saturated Ca(OH)2 solution with 4% inhibitor reached 89%. With lower pH value, corrosion of steel will happen easier even with addition of inhibitor. However, inhibitor will still have effective even to protect carbon steel in fully carbonated concrete. The organic film with characteristics of aromatic groups can be detected on the carbon steel surface in presence of inhibitor, confirming the protection effects for steel.