Degradation of Creep Behaviors of Basalt Fiber-Reinforced Polymer Tendons in Salt Solution

This study investigates the creep behaviors of basalt fiber-einforced polymer (BFRP) tendons as a prestressing material in salt solution. Static tensile tests and creep tests were conducted on the BFRP tendons after aging subjected to salt solution. Experimental variables included the aging temperature and aging duration. The tensile strength, elastic modulus, creep strain, and creep rupture stress of the degraded BFRP tendons are analyzed and discussed. Furthermore, a scanning electron microscopy analysis was conducted to clarify the degradation mechanism of the creep behavior. The results show that the aging temperature and duration in salt solution have a negligible effect on the creep strain increase of BFRP. The ratio of the creep rupture stress to the original tensile strength of BFRP tendons aged in salt solution decreases considerably. However, the ratio of the creep rupture stress to the degraded tensile strength exhibits no degradation, which indicates that the impact of the sustained load is independent of the impact of the salt solution on the mechanical behaviors of BFRP tendons. The appearance of corrosion channels in BFRP tendons, which accelerate successive fiber-matrix debonding under a sustained load, is determined to be the main cause for the degradation of its creep behavior in salt solution. These results provide a reference for the determination of the long-term stress of BFRP tendons used in offshore structures. (C) 2018 American Society of Civil Engineers.