A review on reinforcement corrosion propagation in carbonated concrete-Influence of material and environmental characteristics

Low-binder eco-efficient concretes and carbon uptake are opportunities for mitigating CO2 emissions and reaching net zero goals. However, the risk of corrosion induced by carbonation can accelerate. Here, a metaanalysis of the results of corrosion current density (icorr) obtained from steel embedded in carbonated concrete was conducted considering the characteristics of concrete and environment. The literature review shows higher values of icorr than expected and reported in reference studies and standards at different exposure classes of relative humidity (RH). High levels of icorr were found in low- and high-binder-content concretes, different paste volumes, or estimated porosities. The concrete resistivity, which is less known, shows the best relationship with icorr in carbonated concrete. Resistivity reflects better moisture content, and pore saturation conditions at the steel-concrete interface than the external RH, although seldom reported. Research on the relationship between icorr during the propagation period, carbonation degree, microstructure, residual alkalinity, and resistivity for low-binder concretes is still scarce and needed.

Automated summary

A metaanalysis was conducted to study the corrosion current density (icorr) in carbonated concrete, revealing a higher icorr than expected, especially in low-binder concretes. Concrete resistivity was found to be the most important factor related to icorr in carbonated concrete, reflecting moisture content and pore saturation conditions better than external relative humidity. Further research on the relationship between icorr, carbonation degree, microstructure, residual alkalinity, and resistivity in low-binder concretes is needed.