Durability of BFRP bars and BFRP reinforced seawater sea-sand concrete beams immersed in water and simulated seawater

Abstract

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 environmental 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 characteristics. 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.