Research on the Bonding Performance of the CFRP-Concrete Interface Based on Colloid Thermosensitivity

The bonding performance of carbon fiber-reinforced polymer (CFRP)-concrete interface is an important research area, with adhesives serving as mediators for the transfer of interface stresses. However, there is significant variation in the mechanical properties of adhesives available in the market, and currently there is limited research on the patterns of how adhesive mechanical properties affect interfaces. First, dynamic thermomechanical analysis was used to investigate the glass transition temperature of the adhesive, Tg. Following this, tensile tests were conducted to assess the mechanical properties of the adhesive at various temperatures. Finally, the effects of the adhesive on the interface bonding properties of CFRP-concrete were studied by single shear tests at different ambient temperatures. The test results indicated that when the ambient temperature is lower than the glass transition temperature (Tg), as the temperature increases, although the mechanical properties of the adhesive decreased, the effective bonded length of interface increased significantly, leading to a gradual increase in interface load-bearing capacity. Furthermore, the interface constitutive model was modified by finite-element model inversion. The modified parameters K and tau max exhibited a linear increase relationship with the elastic modulus of the adhesive, and the modified parameter Gf showed a negative exponential power function relationship with the elastic modulus of the adhesive.