Work

Kinetics and mechanism of gallic acid as an ecofriendly corrosion inhibitor for steel rebars in mortar

Year: 2024

Type: article

Abstract: Chloride-induced corrosion of steel rebars embedded in mortar was effectively controlled by blending of gallic acid in wet mixture. Mixing of optimized concentration of gallic acid (GA) inhibitor (0.125%) in mortars considerably increased the charge transfer resistance of embedded rebars (80.11 Ω cm 2 ) in comparison to that noted for the control mortars (3.36 Ω cm 2 ) after 37 cycles of wet/dry treatments. The corrosion inhibition efficiency after this cycle of exposure was of the order of 95%. The studied inhibitor also improved the workability (% flow of wet mix) from 25% for control to 43% at its optimum dosing. It is suggested that GA transforms into negatively charged gallate anions in an alkaline-pore solution of concrete and electrostatically attracted to the positively charged calcium ions, forming a complex with a partial positive charge. This complex interacts with the negatively charged maghemite film formed on rebar surface and forms a protective film of FeO − Ca ++ – GA anion, isolating it from the aggressive electrolyte. The experimental results showed that Ca ++ ion of the concrete had a strong synergistic effect in boosting the inhibitive performance of the GA. The inhibition efficiency increased from 84.1% in the presence of GA only to 97.9% for the mixture of GA and calcium ions.

Source: Scientific Reports

DOI: 10.1038/s41598-024-82166-4

Authors: Abdulrahman Alhozaimy, Raja Rizwan Hussain, Abdulaziz Al-Negheimish, Mshtaq Ahmed, D. D.N. Singh

Institutions: King Saud University, National Metallurgical Laboratory, Council of Scientific and Industrial Research

Language: English

Topic: Concrete Corrosion and Durability

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,590

Funder: King Saud University