Comparison of Two Accelerated Corrosion Techniques for Concrete Structures

Abstract

The galvanostatic method of inducing corrosion is commonly employed in laboratory tests to study the influence of reinforcing bar corrosion on the response of the reinforced concrete beams. However, the surface characteristics of the corroded steel bar are found to be different when the corrosion is induced by galvanostatic method or by natural environment. This study proposes an alternative method of inducing corrosion using an artificial climate environment and seeks to verify if it can be adopted as an accelerated technique for the durability test in place of the galvanostatic method. Two groups of reinforced concrete beams were degraded as a result of the corrosion of steel bars. One group of beams was subjected to the galvanostatic method, while the other group was corroded using the artificial climate environment. Comparative studies on the corroded characteristics of steel bar surface, the mechanical behavior of the corroded bar, and the load-bearing capacity were conducted. The comparisons between the two groups of beams were based on the identical width of corrosion cracking. The comparison revealed significant differences in the two methods. The steel bar in concrete can be corroded using the galvanostatic method, but its electrochemical corrosion process is different from the corrosion process under the artificial climate and natural environment. The differences lead to different corrosion distribution on the surface of the steel bar. The corrosion process and corrosion characteristics of the steel bar under artificial climate environment were similar to that of corrosion under natural environment, suggesting that the artificial climate environment is more representative than the galvanostatic method as an accelerated laboratory test method.