PREDICTING THE PROPAGATION TIME DUE TO GENERAL CORROSION IN CHLORIDE CONTAMINATED REINFORCED CONCRETE STRUCTURES

The propagation stage, from chloride induced corrosion initiation to cracking of the reinforcing steel cover concrete, is one of the critical time periods for modelling the time to repair, rehabilitate, and replace reinforced concrete structures in corrosive environments. In this study, a finite element model was developed to analyze the behaviour of the concrete bridge deck cover subjected to steel corrosion and verified by experimental data. The problem was modelled as a plane strain problem wherein the corrosion products were assumed to be a uniform build-up around the surface of the bar. From the analyses it was indicated that different failure modes govern depending on the geometry and configuration of the reinforcing bars in the concrete cover. Limiting criteria for different cracking modes were established as a function of design variables of the concrete cover depth, bar diameter and bars spacing. A parametric study has been undertaken to quantify the effects of these factors on cracking development.