Corrosion-resistance evaluation of coated and specialty bars

Abstract

The reduction in service-life of reinforced concrete structures caused by corrosion of reinforcing steel is a major problem to the construction industry. The use of specialty steels is one of the strategies suggested to minimize this deterioration phenomenon. In this study, the corrosion-resistance of epoxy-coated and selected specialty steel bars embedded in concrete and exposed to chloride environment was evaluated. The specialty bars considered included two types of epoxy-coated bars with varying degrees of damage, stainless steel bars, stainless clad bars, and a low-carbon chromium steel bar. The corrosion resistance of the investigated reinforcing bars was investigated by measuring corrosion potentials and corrosion current density over a period of about 32 months. As expected, the corrosion resistance of specialty bars was better than that of the black (normal) bars. The corrosion resistance of the epoxy-coated bars decreased with the degree of surface damage. Further, the corrosion-resistance of epoxy-coated bars with up to 1% damage was better than that of the other specialty bars. Additionally, the low corrosion rate noted in the epoxy-coated bars suggests longer service-life of structures built with these bars compared to structures incorporating specialty steel bars considered in the study. The relatively low initial cost of epoxy-coated bars, compared to other specialty steel bars, and their longer life results in a considerable cost saving. Also, the decreased corrosion damage of concrete results in technical (long service-life and safety), environmental (aesthetics) and economic (less overall cost of construction) benefits.

Keywords:

• Reinforcement corrosion
• fusion bonded epoxy coated bars
• stainless steel bars
• stainless clad bars
• low carbon chromium steel bar
• service-life

Acknowledgement

The author acknowledges the support provided by King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia.

Disclosure statement

No potential conflict of interest was reported by the author.