Performance assessment of alko-amine corrosion inhibitors for use as an admixture in reinforced concrete structures: Experimental investigation and mechanism of action

Corrosion in reinforced concrete (RC) is a major issue in the construction industry, giving rise to structural failure, huge repair costs, and safety concerns. To mitigate RC corrosion, chemical corrosion inhibitors (CCI) are commonly used. This study aims to investigate the performance of different alko-amine CCIs for corrosion control in reinforced concrete (RC) structures subjected to chloride-rich conditions. The experimental program was divided into two levels: investigations comprised of quick testing on bare rebars, suitable for industries, and analysis which comprised of electrochemical investigation in simulated concrete pore solution and testing on rebar embedded in concrete, suitable for research labs. The interaction between inhibitors and steel was examined through surface analytical techniques such as AFM and XPS. Finally, the inhibition mechanism for the CCI was proposed. The alko-amines were found to show a strong dependence on their molecular structure for the formed film integrity. Monoethanolamine (MEA) and methyl ethanolamine (MeEA) formed a denser and more uniform film compared to dimethyl ethanolamine (DMeEA) and ethyl monoethanolamine (EMEA). MeEA showed the highest inhibition efficiency in both simulated pore solution environments and when used as an admixture in RC.