Durability of glass FRP bar‐reinforced seawater–sea sand concrete beams under sustained loading in a subtropical coastal environment

Abstract The replacement of conventional bars with fiber‐reinforced polymer (FRP) bars in seawater–sea sand concrete (SSC) structures is a promising method for sustainable construction. To promote the engineering application of the aforementioned structures, the primary objective of this study was to investigate the concerns regarding the durability of SSC beams reinforced with GFRP bars. For this purpose, three‐point bending tests were conducted on GFRP bar‐reinforced SSC beams to examine the coupled effects of sustained loading and exposure to a subtropical coastal environment on the flexural behavior of exposed SSC beams. The test results revealed that SSC beams reinforced with GFRP bars exhibited excellent durability in a subtropical coastal environment. The coupled effect of sustained loading and exposure to the subtropical coastal environment had an insignificant negative influence on the ultimate flexural capacity of GFRP bar‐reinforced SSC beams at 540 days of age. The failure mechanism of the exposed GFRP bar‐reinforced SSC beams was concrete crushing due to overreinforcement. Finally, the flexural capacity of the exposed beams was predicted by a function of the degradation in the tensile strength of the GFRP bars. Highlights The coupled effects of loading and environmental exposure on GFRP‐SSC beams were examined. The failure mechanisms of the exposed GFRP‐SSC beams was investigated. The long‐term flexural capacity of the GFRP‐SSC beams was predicted.