Corrosion rate of carbon steel in carbonated concrete – A critical review

The need to reduce CO2 emission and to obtain materials having a reduced environmental footprint is leading to a reduction of the clinker content in the cements. The carbonation of concrete is faster and corrosion of steel in carbonated concrete during the propagation phase is getting more and more interest in science and practice. The present literature review summarises the state of the art, reporting corrosion rate data for a broad range of cement types, w/b ratios and environmental conditions. Correlations between corrosion rate and the main influencing parameters are elaborated and discussed. It results that the corrosion rate of steel in carbonated concrete is not under ohmic control. More important are the degree of pore saturation and the effective steel area in contact with water filled pores. It also emerges that the new blended cements have to be systematically studied with respect to the corrosion behaviour of steel in carbonated concrete.