Electrochemical meaning of cumulative corrosion rate for reinforced concrete in a tropical natural marine environment

Abstract

The objective of this paper is to discuss the meaning of cumulative corrosion rate (CCR) of reinforced concrete in a tropical marine microclimate of the Yucatan Peninsula identifying four stages that correspond to passivation, beginning of depassivation, breakdown and formation of subsequent corrosion layers, and nucleation and development of cracks. Sixty Portland cement concrete cylinders were exposed in a tropical marine environment at 50m from the seashore. One-half of the samples had a reinforcing bar embedded at the center of the sample (corrosion measurements) and the other half was made with plain concrete (chloride measurements). Five water/cement (w/c) ratios and three times of curing (CT) were tested representing the common practices of this region. The corrosion rate was monitored using the linear polarization resistance technique (Rp) which enables calculating the apparent and cumulative corrosion rate. Representative results indicated that iCCR was effective not only to detect the beginning and duration of the reported stages but also to find the right influence of CT and w/c ratios on the corrosion performance of reinforced concrete.