Bond performance between ribbed BFRP bar and seawater sea-sand concrete: Influences of rib geometry

To solve the corrosion problems of steel bars in reinforced seawater sea-sand concrete (SSC) structures, fibre reinforced polymer (FRP) bars are promising alternatives. The bond between FRP bars and SSC determines the capacity and serviceability limit states of structures composed by them. The rib geometry of FRP bars is one of the most important factors influencing their bond performances with concrete. However, it has not received sufficient attentions on existing studies and standards. Therefore, this study investigated the bond performance between SSC and ribbed basalt FRP bars with different rib geometry through pull-out tests on 36 specimens. It is found that the bond strength declined with the increase of rib width and dent width, while the increase of rib height improved the bond strength. The ultimate and residual slip were strongly correlated with the rib spacing. Finally, a bond strength model that can well predict the experimental results was proposed.