The use of TEA·H3PO4 and TEA·C18H30O3S as eco-friendly corrosion inhibitors in cementitious materials: An experimental and theoretical study

Chloride penetration , facilitated by drying-wetting cycles, poses significant threats to reinforced marine concrete structures . In this study, the corrosion inhibition effects of triethanolamine dodecylbenzene sulfonate (TEA·C 18 H 30 O 3 S, TDS) and triethanolamine phosphate (TEA·H 3 PO 4 , TP) were investigated using mortar specimens. Electrochemical tests including electrochemical impedance spectroscopy and potentiodynamic polarization test were performed. The morphology and Vickers hardness of the steel/mortar interface were analyzed. Molecular dynamics and quantum mechanical simulations were conducted to explore the interactions between the inhibitors and the iron surface. The results demonstrated that the inhibition efficiency of TP was high, while TDS only presented some effect within limited drying-wetting cycles. After 24 wetting-drying cycles, the inhibition efficiency of TP reached 59.29 %, TDS exerted a detrimental effect on reinforcement corrosion , and the inhibition efficiency was −410.96 %. At the mortar/steel interface, the irregular defects were curtailed and the Vickers hardness was improved by TP. Meanwhile, TDS entrained large hydration pores. The adsorption of the inhibitors on the iron surface is primarily through the benzene ring , P O and N C bonds, where the TEA-Fe adsorption is the most stable among the studied chemical components.