Durability assessment of the bonding performance between GFRP rebars and UPC in aquatic environments

Glass Fiber Reinforced Polymer (GFRP) bars and Unsaturated Polyester resin Concrete (UPC) offer superior corrosion resistance, making them viable alternatives to steel bars and traditional concrete in water-related projects. When both materials function as load-bearing components in water environment engineering, the performance of their bonding properties is of critical importance. This study examines the bond properties of GFRP bars-UPC under various aging conditions by establishing water environments at temperatures of 25 °C, 40 °C, and 60 °C. Central pull-out specimens of GFRP bars-UPC were subjected to these environments to evaluate their bond strength and bond-slip curves at various aging stages. The study reveals that the bond strength of GFRP bars-UPC diminishes as temperature and aging duration increase. Additionally, the relative slip values and residual bond stresses of aged specimens are lower compared to unaged specimens. The MBPE and continuous curve models accurately represent the bond-slip behavior of aging GFRP bars-UPC.