Inhibitory effects of 5-aminouracil on cathodic reactions of steels in saturated Ca(OH)2 solutions

Abstract The inhibitory effects of 5-aminouracil on cathodic reactions of steels were investigated using saturated Ca(OH) 2 solution to simulate the environment in pores in concrete. Polarization measurements showed that 5-aminouracil effectively inhibited these cathodic reactions, indicating the potential of 5-aminouracil as an inhibitor for macro-cell corrosion in concrete/soil systems, which are caused by cathodic reactions in concrete. Cathodic reactions were inhibited in accordance with the Langmuir adsorption isotherm. FT-IR and XPS measurements suggested that 5-aminouracil was adsorbed onto cathodic portions of the steel through the formation of a coordination bond with the amino group, mainly in the form of dimer.