A Building Research Establishment experiment revealed significant differences in the corrosion resistance of various bar reinforcements. Galvanized steel, unfortunately, exhibited the poorest performance among the tested types. Corrosion initiated when the chloride content in the concrete surpassed a threshold of 0.4% by cement weight.
In contrast, epoxy-coated bars demonstrated superior corrosion resistance compared to galvanized steel, effectively delaying the onset of cracking. However, the undisputed champion in this experiment was stainless steel. Notably, austenitic stainless steel remained entirely unaffected by corrosion even in the presence of chloride contamination within the concrete.
This research, referenced in K. W. J. Treadaway’s 1988 work, highlights the importance of material selection for reinforcement in environments prone to chloride exposure. While galvanized steel may offer some initial protection, its susceptibility to corrosion under certain conditions necessitates careful consideration. Epoxy-coated bars provide a significant improvement, but stainless steel, particularly austenitic grades, emerges as the most robust and reliable option for long-term corrosion resistance.
These findings underscore the need for engineers and specifiers to carefully evaluate the environmental conditions and potential for chloride contamination when choosing reinforcement materials. By selecting the appropriate reinforcement, the longevity and structural integrity of concrete structures can be ensured, even in aggressive environments.