Protection against Reinforcement Corrosion Using Phosphoric Acid-Based Rust Converter

Abstract

The protective properties of a newly developed phosphoric acid-based rust converter are investigated for reinforcement corrosion under chloride-contaminated concrete environment. The electrochemical evaluation of specimens after 6 years (2 years of wet-dry exposure in 3.5% sodium chloride solution and 4 years in dry laboratory environment) demonstrated that treating the reinforcing bar with the newly developed product significantly reduced the corrosion rate compared to the control reinforcing bar. Based on the results of Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy, a new mechanism is described for the transformation of unstable rust phases into stable phases. It is observed that iron phosphate remains entrapped with corrosion products formed on the surface of the treated steel reinforcing bar, even after 6 years of exposure.