Long‐Term Transverse Shear Behavior Evaluation and Prediction of Glass Fiber‐Reinforced Polypropylene Bars in Marine Environments

ABSTRACT Transverse shear performance is the weakness of glass fiber‐reinforced polypropylene (GFRPP) bars, and its long‐term stability in marine environments is crucial to the safety and life of marine structures. This study systematically investigated the transverse shear behavior of GFRPP bars after exposure to distilled water (DW), seawater (SW), and an alkaline SW sea‐sand concrete pore solution (AS) at different temperatures (25°C, 40°C, 60°C) and durations (4, 8, 12 weeks), and conducts analysis of degradation mechanisms and service life prediction. The results indicate that the transverse shear strength (TSS) retention decreases with increasing temperature and exposure time, with the most significant degradation observed in AS. Elevated temperature has a threshold effect on accelerating degradation, as the rate increases sharply when exceeding 40°C. A modified TSS retention prediction model with higher accuracy ( R ² > 0.96) is proposed. The predicted service life was (TSS retention drops to 70%) 935, 559, 419 days in SW and 172, 125, 105 days in AS at 5.7°C, 14°C, 20.3°C respectively. This study presents long‐term transverse shear data and a service life prediction model for GFRPP bars, thereby providing data and theoretical support for their application in marine engineering.