Active and passive protection of steel reinforcement in concrete column using carbon fibre reinforced polymer against corrosion

Abstract

This study aims to investigate the efficiency of active and passive protection of the pre-corroded steel reinforcement in reinforced concrete (RC) columns using an externally bonded carbon fibre reinforced polymer (CFRP) wrap. Active protection is a novel technique used to impede corrosion achieved by employing the CFRP wrap as the anode of the impressed current cathodic protection (ICCP). Passive protection denotes the anti-corrosion behaviour of the CFRP fabric. Nine reinforced concrete columns with different degrees of corrosion (theoretical mass losses of 1%, 3%, and 6%) were prepared and then treated with different protection methods (non-protection, passive protection, and active protection) by exposing them to wet–dry cycles. By measuring the steel potential, linear polarization, and electrochemical impedance spectroscopy (EIS) of all investigated specimens, the efficiency of active protection was found to be closely related to the degree of the pre-corrosion of the protected specimens. Furthermore, the efficiency of active protection decreased with time, which may be attributed to the deterioration of the CFRP anode and CFRP/concrete interface. Passive protection was proven to be effective in every case, however, it can only slow down the corrosion process but cannot stop the elicited corrosion response.