Prediction of service life of concrete structures using corrosion rate model

The uncertainties that exist in the chloride diffusion model may lead to considerable error in the prediction of the time to initiation of corrosion in the service life estimation of concrete structures. An alternative approach based on polarisation resistance (Rp value) has been proposed. Enhancement of the service life of concrete made using blended cements was measured experimentally using the electrochemical impedance technique (EIS) in the presence of 0, 0·5 and 1% of added chloride. The time to initiation of corrosion (Ti) predicted from the Rp value agreed well with the value from the weight loss measurement, whereas it was overestimated by the chloride diffusion model. Using the Maaddawy mathematical model, the time to propagation (Tp) was obtained. From the results it was concluded that in the presence of 1% of added chloride, the time to failure Tf = (Ti + Tp) of Portland pozzolana cement (PPC) and Portland slag cement (PSC) concrete was four and ten times higher than that of ordinary Portland c...