SERVICE LIFE FORECASTING FOR REINFORCED CONCRETE INCORPORATING POTENTIAL-DEPENDENT CHLORIDE THRESHOLD

摘要

The chloride corrosion threshold of steel in concrete depends not only on concrete and steel properties but also on the potential of the steel while it is still in the passive condition. A deterministic model to predict corrosion in reinforced concrete structures is presented,incorporating potential dependence and corrosion macrocell effects,resulting in coupling of the corrosion initiation and propagation stages. The model is applied to a generic partially submerged reinforced concrete marine pile. An analysis is made of sensitivity of model output to input parameters including the rate of dependence of threshold on potential,concrete resistivity,oxygen diffusivity and size of the steel zone activated upon reaching the chloride threshold. The results are contrasted with those of a comparable system where the threshold is not potential dependent.