Failed concrete analysis and development of mitigation strategies to combat rebar corrosion

Corrosion of the reinforcing steel bar (rebar) prevails as a serious issue, in the construction sector, leading to the deterioration of concrete infrastructures. The extent of concrete failure due to rebar corrosion depends greatly on the environmental conditions. The present paper describes a detailed analysis of the rebar corrosion under various environmental conditions and the development of different coatings to combat rebar corrosion. It also details the role of severe corrosive environment and the influence of microbial interactions on rebar corrosion. The long-term exposure (14 days) of the rebar to different bacterial suspensions such as E. coli, B. subtilis, and seawater consortium indicate that the rebar undergoes severe surface degradation in seawater consortium as compared to the other suspensions. The suitability analysis of the zinc phosphate and electroless nickel coatings to combat rebar corrosion in severe corrosive medium confirm nickel coated rebar as more corrosion resistant than zinc phosphate coated/bare rebars. The biocorrosion resistance analysis of zinc and composite zinc coated rebars in seawater consortium after long-term exposure (28 days) indicates composite zinc coated rebar as the best with the lowest bacterial survivability percentages in all the bacterial suspensions. The composite coated rebar exhibits attractive electrochemical stability even after long-term bacterial exposure in seawater consortium, and acts as a protective coating with superior biocorrosion resistance and anticorrosion characteristics.