Effect of pre-existing longitudinal and transverse corrosion cracks on the flexural behaviour of corroded RC beams

Assessing the residual capacity of corroded reinforced concrete (RC) beams depends on quantifying the corrosion cracks and rebar cross-section loss, and understanding their influence on the structural behaviour. Relations between corrosion crack widths and cross-section loss have been developed in the literature, and experimental studies have shown a decrease in the flexural capacity of corroded RC beams. However, their results were only related to longitudinal cracks and rebar cross-section loss. In real structures, corrosion of stirrups causes transverse cracks. In this paper, their influence on rebar pitting and failure of corroded beams is investigated through an experimental test programme in which RC beams are corroded and then tested in bending. Firstly, the effect of transverse cracks on the relation between crack widths and cross-section loss is studied. Secondly, the role of each type of corrosion damage on the flexural failure of the beams is investigated. It is found that transverse cracks lead to localized cross-section loss causing non-linearity in the relation between the longitudinal crack widths and the cross-section loss. Additionally, it is found that longitudinal corrosion cracks decrease the number of flexural cracks, while transverse cracks form weak spots to initiate the beam failure. Furthermore, it is observed that beams fail at the location of either the transverse cracks or the minimum rebar cross-section or both. Moreover, transverse corrosion cracks may lead to misaligned minimum cross-sections on the tensile rebars, which cause a skewed critical cross-section during bending failure. Finally, the study concludes that pre-existing longitudinal corrosion cracks deteriorate the tension-stiffening effect, while transverse cracks cause local pits in the tensile rebars and affect the failure mechanism of the beams.

Jaar van publicatie:2022

Toegankelijkheid:Open