Assessment of Anchorage Capacity of Naturally Corroded Reinforcement

Corrosion of reinforcement is a significant cause of deterioration in existing structures. While this topic has been extensively studied using artificially corroded test specimens, little is known about the actual response of naturally corroded structures. Overall, the literature suggests that drastic reduction of the corrosion time, i.e. from years to days, in accelerated corrosion process, might markedly influence the bond and the anchorage capacity of a reinforced concrete member.

Consequently, the anchorage capacity of specimens with naturally corroded reinforcement was investigated. Since a large scatter was observed in the tests of the first series, see [1, 2], fourteen more specimens were tested in a second round using samples from the other side of the same bridge. The specimens were carefully documented regarding crack patterns, crack widths, and spalled regions before testing. In all cases, diagonal shear cracks preceded a splitting-induced pull- out failure; i.e. anchorage failure was achieved as expected. Subsequent work will combine results from both test series, such as load versus deflection, free end-slip and crack patterns; and compare these with the predictions from detailed nonlinear finite element modelling, using the available bond and corrosion models. These will result in a better understanding of the structural behaviour of corroded reinforced concrete structures to field conditions.