Corrosion Behavior of Corrosion-Resistant Steel Reinforcements in Normal-Strength and High-Performance Concrete: Large-Scale Column Tests and Analysis

Abstract

This paper presents the findings of a systematic comparison of the corrosion behavior of corrosion-resistant steel reinforcements, including epoxy-coated steel, high-chromium steel, and stainless steel reinforcement in normal-strength concrete (NC) and high-performance concrete (HPC) columns in an accelerated chloride attack environment for 24 months. The corrosion potential and corrosion rate of the reinforcements were monitored using electrochemical methods, and the degradation of the axial compressive capacity of 40 corroded columns over time was obtained and discussed. Findings indicated that corrosion-resistant reinforcements showed significantly better corrosion performance: no corrosion was observed for intact epoxy-coated and stainless steel reinforcements, and less corrosion (54%) was found on high-chromium steel than conventional mild steel in NC, while similar corrosion rates were found for mild steel and high-chromium steel reinforcements in HPC. Results also indicated that HPC provided reliable protection to the embedded reinforcements, showing smaller corrosion rates than those in NC. The measured average corrosion rate of mild steel and high-chromium steel reinforcements in HPC was 17 to 37% of that in NC. In addition, an analytical model was synthesized to predict the axial load-axial shortening relationship of the corroded circular reinforced concrete columns.