Inhibition mechanisms of HAIB on Q235 rebar in the simulated concrete pore solution

FJ Wang and ZY Xin and YC Wang and SY Sui and Q Zheng and JY Jiang, JOURNAL OF BUILDING ENGINEERING, 72, 106565 (2023).

DOI: 10.1016/j.jobe.2023.106565

The safety incidents and economic losses caused by the failure of reinforced concrete structures are far greater than expected, resulting in enormous damage. The application of corrosion inhibitors is currently one of the simplest but most cost-effective ways to prevent and retard corrosion of reinforcing steel. Understanding the anti-corrosion mechanisms of inhibitors on mild steel is beneficial for the design of new inhibitors with a high efficiency. This article in view of the existing reinforced concrete structure of bidirectional electromigration repair technology, launched on a new type of corrosion inhibitors for cationic research. Hydroxyl-functional imidazole ionic liquid (HAIB) was prepared with imidazole as raw material, which were able to create multiple adsorption sites with steel bars. EIS and LPR tests were applied to study the anticorrosion mechanism of HAIB on Q235 steel bar in a simulated concrete pore solution with 3.5% NaCl. The electrochemical results show that the addition of HAIB reduces the corrosion current density and increases the Rp values of the steel bar. Some surface analysis methods, including scanning electron microscope, atomic force microscope, and X-ray electron energy spectroscopy were also employed to investigate the adsorption of HAIB on steel bar. Microscopic test results showed that a protective film was formed on the steel bar surfaces, through a combinational effect both physically and chemically, thereby improving the corrosion resistance. Additionally, our quantum chemical calculations successfully predicted the reactive sites in the HAIB molecule. The results indicate that nitrogen atoms are prone for electrophilic attack from Fukui function calculations. Owing to its multi-site and adsorption features, the HAIB is manifested to be a superb corrosion inhibitor.

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