Influence of Corrosion Conditions on Prestressing Force and Residual Tensile Capacity of Corroded Prestressed Concrete Steel Strands

This paper investigates the mechanism of the corrosion pattern of wires on the prestressing forces of prestressed concrete (PC) strands. A rigid frame testing machine combined with an electrically accelerated corrosion device was used to test 16 steel strands. Specimens subjected to the tensile load of 50% of the tensile strength were divided into three groups according to the target corrosion level (mass loss). The rigid frame testing machine can remain the prestressing force, and the force and deformation were measured continuously during the corrosion test. The prestress was degraded in two stages; the beginning and development of the second stage being related to the maximum cross-sectional area loss and fracture type of the wires, respectively. The prestress loss of the strands was the result of the internal force balance after the deterioration of the tensile properties. It was found that the deterioration process of the ultimate tensile capacity related to the fracture type of the wire. The fracture type of PC strand was influenced by the shape and the distribution of the cross-sectional area loss of corroded wires.