Effect of corrosion on bond performance of corroded pretensioned prestressed concrete beams

The bond behaviour between corroded strand and concrete in pre-tensioned prestressed concrete beam is investigated experimentally in the present paper. A total of nine pre-tensioned beams are fabricated and eight of them are accelerated to concrete cracking, with one uncorroded beam as control. Data on the distribution of corrosion-induced crack, force-slip responses, and failure modes are obtained. Effects of strand corrosion on the load-slip curves are studied. At last, the final failure modes and the ultimate strength of the beams are analysed. Experimental results show that the bond stiffness and strength do not decrease until the corrosion loss and crack width exceeds 5.1% and 0.27 mm, respectively. The failure mode of beams change with the increasing of strand corrosion. When the corrosion loss is less than 5.1%，beams PS0-PS4 fail in concrete crushing, accompanying with strand yielding. When the corrosion loss exceeds 6.91%, the beams fail in strand rupturing without detecting yielding plateau. The degradation of strand tensile strength plays a more important role than degradation of bond strength when strand reaches certain corrosion loss.