Fatigue performance of kiloton CFRP cable after hygrothermal and freeze–thaw cycles

The application of carbon fiber reinforced polymer (CFRP) cable with light weight and high strength can improve the service performance of bridge structures in plateau harsh service environments. But the performance evolution behavior of CFRP cable under complicated service environments of fatigue load, hygrothermal and freeze–thaw cycles is unknown. In this paper, the tensile fatigue performance of CFRP rods used for cable before and after hygrothermal and freeze–thaw cycles is investigated experimentally. The tensile fatigue and residual tensile performances of kiloton CFRP cable are verified after hygrothermal and freeze–thaw cycles. Optical frequency domain reflectometry technology is employed to monitor the stiffness degradation of CFRP cables during fatigue loading. The results indicate that the hygrothermal and freeze–thaw cycles release the residual stress within CFRP rod, which improves the fatigue resistance. By contrast, the hygrothermal and freeze–thaw cycles have no significant effect on stiffness degradation of CFRP rod. The kiloton CFRP cable can withstand 2,000 k cycles of tensile fatigue after hygrothermal and freeze–thaw cycles, and the stiffness degradation of CFRP cable is negligible. The residual tensile bearing capacity of CFRP cable after fatigue is 10,731 kN, corresponding to a residual strength retention rate of 105 %. These findings provide essential validation data for the application of kiloton CFRP cables in bridge construction.