Durability of BFRP Bars and BFRP Reinforced Seawater Sea-Sand Concrete Beams Immersed in Water and Simulated Seawater

Seawater sea-sand concrete (SSC) members reinforced with fiber-reinforced polymer (FRP) have considerable development potential. However, an adverse effect of alkalinity in seawater sea-sand concrete on the long-term performance of FRP was found, and the durability of FRP reinforced SSC structures in seawater is always a significant concern. Thus, this study examined the durability of basalt-fiber-reinforced polymer (BFRP) bars reinforced SSC beams in simulated seawater and tap water. Tensile and four-point bending tests analyzed the tensile properties of the BFRP bars embedded in SSC and the flexural performance of the BFRP-reinforced SSC beams respectively. The tensile strength of the BFRP bars decreased with the immersion time and the environ-mental temperature. Further, the tensile strength of the BFRP bars declined more severely in tap water than in seawater. The failure of the BFRP-reinforced SSC beams changed from shear to flexural failure owing to the reduction of the balanced ratio of the BFRP-reinforced beams in seawater and tap water. Moreover, the ultimate load-carrying capacity of the BFRP-reinforced SSC beams decreased, and they showed brittle failure character-istics. Finally, the ultimate load-carrying capacity of the BFRP-reinforced beams was predicted as a function of the degradation of the tensile strength of the BFRP bars. The developed equation conservatively estimated the flexural-load-carrying capacity of the BFRP-reinforced beams in actual oceanic environments.