Time to surface cracking and crack width of reinforced concrete structures under corrosion of multiple rebars

Concrete cover cracking caused by corrosion of reinforcement is one of major deterioration mechanisms for reinforced concrete structures. In practice, time to surface cracking and crack width evolution are of significance in regards to the assessment of serviceability of reinforced concrete structures. Literature review suggests that, although considerable research has been undertaken on corrosion-induced concrete cracking, little has been focused on corrosion of multiple reinforcing bars, especially by considering the non-uniform corrosion process. In this paper, a time-dependent non-uniform corrosion model is established. A cohesive crack model is then formulated to simulate arbitrary cracking in the whole cover of concrete structures. Two typical cover failure modes (i.e., “delamination” and “combined delamination and corner spalling”) have been simulated under the non-uniform corrosion of multiple reinforcing bars and found dependent on spacing of reinforcement and fracture energy of concrete. The effects of corrosion, geometric and mechanical parameters on the time to surface cracking after corrosion initiation and the crack width evolution are also investigated and discussed. The developed model is partially verified by comparing the results with those from experimental tests on uniform corrosion of multiple reinforcing bars.