Condition Assessment of Reinforced Concrete Systems with Fusion Bonded Epoxy Coated Rebars

Abstract

Corrosion assessment of reinforced concrete (RC) structures with fusion-bonded-epoxy (FBE)-coated steel rebars is a challenge because the common inspection methods and data cannot be applied or interpreted in the same way as that for the systems with uncoated rebars. If corrosion detection tools based on techniques such as half-cell potential (HCP), linear polarization resistance (LPR), or electrochemical impedance spectroscopy (EIS) are used for the assessment of systems with FBE-coated steel rebars without considering the difference in the electrochemical conditions between coated and uncoated systems, then the interpretation can result in the inability to detect ongoing corrosion. Therefore, the objective of this paper is to examine the suitability of these inspection methods and data to be applied to the RC systems with FBE-coated steel rebars. For this, the suitability of test methods on HCP, LPR, and EIS for assessing corrosion conditions of RC structures was assessed using laboratory specimens and field structures. Field investigation using HCP shows that the HCP could not detect corrosion of FBE-coated steel rebars unless the coating was severely disbonded due to corrosion of steel rebars. Also, the suitability of test methods on HCP, LPR, and EIS was assessed by additional laboratory specimens. Although complex, only the EIS technique could reliably detect the corrosion conditions of the FBE-coated steel rebars embedded in concrete. Therefore, a way forward to assess RC structures using the EIS technique is proposed.