Effect of organic silicon quaternary ammonium salts on mitigating corrosion of reinforced steel induced by SRB in mild alkaline simulated concrete pore solution

The corrosion damage of 20SiMn steel by sulphate-reducing bacteria (SRB) and the mitigation effect of organic silicon quaternary ammonium salt (OSA) were studied in sterilized mild alkaline simulated concrete pore solution (STR) with different additions of SRB and OSA at pH 9.35 for 28 days. Uniform corrosion occurs in STR medium while slight localized corrosion is observed in STR + OSA medium, and localized pitting corrosion occurs in STR + SRB and STR + SRB + OSA media. The largest pit depth reduces from 36.70 mu m in STR + SRB medium to 3.31 mu m in STR + SRB + OSA medium due to the mitigation effect of OSA. The corrosion rate reflected by weight loss and electrochemical impedance spectroscopy (EIS) results presents the order of STR < STR + OSA < STR + SRB + OSA < STR + SRB, which also proves that the presence of SRB can accelerate corrosion in a carbonated medium. However, OSA as an efficient bacteriostatic agent can reduce the excessive growth of SRB and thus reduce corrosion. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

The study found that OSA can mitigate the corrosion damage of 20SiMn steel and reduce corrosion by inhibiting the excessive growth of SRB. The corrosion rate measured indicates that the presence of SRB accelerates corrosion in a carbonated medium, while OSA can reduce the corrosion rate by controlling SRB growth.