Influence of seawater sea sand concrete environment on the long‐term tensile properties of pultruded basalt and basalt‐carbon‐hybrid fiber reinforced polymer profiles

Abstract To reveal the durability of fiber‐reinforced polymer (FRP) profiles, which differ from FRP bars due to the clear variations in the internal structure of the fibers. This study experimentally investigated the tensile properties of FRP profiles in the seawater sea sand concrete (SSC) environment at 25, 45, and 60°C. Unidirectional basalt FRP profiles, multidirectional basalt FRP profiles, and basalt and carbon hybrid FRP profiles were considered. SEM analysis was performed to evaluate the corrosion mechanism. Results show that the strength degradation of FRP profiles accelerated with rising ambient temperature due to resin corrosion in hyperthermia. After 63 days of immersion in the SSC environment solution, multidirectional basalt FRP (BFRP) profiles exhibited more severe corrosion than unidirectional BFRP profiles (82.5% and 88.2%, respectively). The hybrid FRP profiles exhibited a strength retention of 86.4%, which was higher than that of multidirectional BFRP profiles due to the superior alkali resistance of carbon fibers compared to basalt fibers. In addition, prediction models of FRP profiles based on the Arrhenius relation were proposed with a high correlation coefficient of R². Highlights Durability of FRP profiles in SSC environment was studied. Basalt and carbon fibers hybrid reinforced multidirectional polymer profiles. Corrosion mechanism of FRP profiles was revealed. Tensile property prediction model of FRPs in SSC environment was proposed.