Axial compressive behaviour of simulated corrosion-damaged RC columns retrofitted with UHPFRC jackets subjected to dry-wet cycling condition

Abstract

An experimental investigation was conducted on the axial compressive behaviour of simulated corrosion-damaged reinforced concrete (RC) columns retrofitted with ultra-high performance fiber-reinforced concrete (UHPFRC) jackets. Nine RC columns were casted, retrofitted and tested. The influences of the thickness of UHPFRC jackets and the heated dry-wet cycle accelerated corrosion on the retrofitting effectiveness were explored. The failure modes, axial load versus axial shortening behaviour, initial stiffness, and ductility of the columns were discussed to evaluate their structural performance under axial compression. The results showed that UHPFRC jacket can provide a substantial enhancement in the load-carrying capacities, with benefits amplified by the increased jacket thickness (from 16.51% to 46.41%). Even subjected to the dry-wet cycle accelerated corrosion, these retrofitted columns can maintain a significant portion of their load-carrying capacities (around 97%). By acting as a protective barrier, UHPFRC jackets drastically reduce the corrosion rate of RC columns (from 3.02% to 0.35%), illustrating their capacities to safeguard the structural integrity of the columns against the environmental influence. This finding underlines the potential efficacy of UHPFRC jackets in RC column retrofitting. Finally, a systematic method to calculate the load-carrying capacity is proposed to ascertain the capacity contributions from different parts of column.