Influence of additional zinc wire on corrosion morphology and degradation of mechanical properties of bridge cable

Cables are the main force-transfer components of cable-stay bridges, and the safety and durability of the bridges will be threatened when the cables are seriously corroded. In this study, artificial accelerated corrosion, three-dimensional topography scanning and mechanical properties testing were carried out to explore the mechanism of the influence of additional zinc wire on corrosion expansion characteristics and mechanical properties degradation of the cables. Firstly, high-strength steel wire cable specimens with zinc wire and without zinc wire (control group) were prepared, and the artificial accelerated corrosion was carried out for 4, 8, and 12 weeks by spraying droplets through the annular openings set up in the sheaths to simulate the damage of the sheaths. Secondly, the Holon 3DX+ non-contact scanner was used to construct the point cloud model of the cable, and the influence of zinc wire on the corrosion expansion of high-strength steel wires was analyzed. Finally, the MTS testing machine was utilized to conduct static tensile tests on high-strength steel wires with varying degrees of corrosion. A correlation model between the cross section loss rate and the mechanical properties of the corroded high-strength steel wires was established, and the load-bearing performance of the cable was evaluated. The results show that after 4, 8, and 12 weeks of accelerated corrosion, the average values of the maximum section loss rate of the steel wire at the sheath opening of the zinc-added wires were reduced by 47.14%, 62.68%, and 38.70%, respectively, compared with those of the zinc-free wires; the average values of the ultimate strength of the steel wires at the sheath openings and the average values of the yield strength were increased compared with those of the cables without zinc wire by 0.17%, 6.12%, 5.55%, and -0.31%, 8.54%, and 6.24%, respectively; and the residual load carrying capacity of the cable was increased by 0.16%, 5.41%, and 4.83%, respectively.