Corrosion behavior of bent plain reinforcing bars used in concrete

Reinforcing bars sometimes need to be bent during the construction of reinforced concrete structures and these bent portions develop very high levels of plastic strains. This work presents a comprehensive study on the magnitude of tensile and compressive strains induced during bending, and the corrosion behavior of bent bars using electrochemical and immersion tests carried out in chloride-contaminated simulated concrete pore solution. A detailed study of the microstructural changes in bar due to bending and their relationship with corrosion is also presented. Results indicate higher corrosion tendency of the strained location as compared to the unstrained location. The corrosion rate increases with the angle of the bend and can be principally attributed to changes in surface condition, microstructure and accumulation of residual tensile and compressive strains.