Experimental Investigation on the Interfacial Bond Failure Between FRP Bars and Sea Sand Concrete

The interface between the fiber-reinforced polymer (FRP) bars and sea sand concrete (SSC) is to connect the two materials, and the interfacial bonding performance (IBP) is crucial for the load-bearing capacity of structural members. To investigate the impacts of different factors, including bar type, bar diameter, and concrete strength, on the IBP between FRP bars and SSC, pull-out tests are performed on twenty-seven specimens.Based on the thick-walled cylinder theory, a semi-empirical model of interfacial ultimate bond strength at ambient temperature was proposed. The results show that the early interfacial bond strength of FRP bars-SSC specimens is slightly higher than that of steel rebar-SSC specimens. The profile of ribs has a greater impact on the IBP than the bar type and bar diameter. During the pull-out process, the surface of FRP bars is severely worn, and some fibers on the bar surface undergo brittle fracture, resulting in a reduction of interfacial bond strength. The interfacial bond strength estimated by the proposed model is in good agreement with the experimental results.