MODELLING OF INTERFACIAL DEBONDING MECHANISM BETWEEN GFRP BARS AND SEA SAND CONCRETE AFTER HIGH TEMPERATURE

The replacement of river sand with sea one can solve its shortage for construction, and the combination of glass fiber-reinforced polymer (GFRP) bars with sea sand concrete (SSC) can avoid the problem of structural durability caused by reinforcement corrosion. The interface debonding mechanism of the interfaces between GFRP bar and SSC after high temperature is still unclear. The studies on FRP-SSC bond behavior contribute to their development. A new analytical bond-slip model, named as exponential-hyperbolic model, is proposed to describe the interface behavior between GFRP bars and SSC after high temperature. Considering the high-temperature effect parameters determined by the empirical formula, this study develops a finite element model with the cohesive zone model (CZM) and concrete damaged plasticity (CDP) model to simulate the GFRP-SSC interface behavior after high temperature based on ABAQUS. The numerical results are verified by comparing them with the pull-out test data. Results show that the simulated results agree well with the experimental observations, the damage of SSC is mainly concentrated near the loading end of the interfacial bonding section after elevated temperature, the stress decline with increasing temperature, the interface bond behavior of GFRP-SSC is similar to that of GFRP-river sand concrete, the ultimate bond strength loss rate (LR) is slightly greater than the tensile strength LR of the GFRP bar, and the LR increases with improving concrete strength grade.