As an important component, the bond behavior of carbon fiber-reinforced polymer (CFRP)–concrete interface for a reinforced concrete (RC) beam is very significant. In this study, a theoretical model was established to analyze the flexural behavior of CFRP-strengthened RC beams, and the CFRP–concrete interfacial bond–slip relationship under hygrothermal environment was unified into one model. Two failure criteria corresponding to two types of failure modes, i.e., concrete crushing and intermediate crack (IC)-induced debonding, were developed. Through the theoretical model, the flexural behavior of deflection, interfacial shear stress distribution and ultimate load of a CFRP-strengthened RC beam under hygrothermal environment were obtained and predicted. Moreover, the theoretical model was verified by test results. The results showed that the hygrothermal environment had a significant impact on the CFRP–concrete interface behavior. Compared with the control beam without hygrothermal environment pretreatment, the deflection and ultimate load of the strengthened RC beam decreased by 51.9% and 20%, respectively.

作为重要组成部分，碳纤维增强聚合物（CFRP）-混凝土界面对钢筋混凝土（RC）梁的粘结性能非常重要。在这项研究中，建立了一个理论模型来分析CFRP加固的RC梁的弯曲行为，并将湿热环境下CFRP与混凝土的界面粘结滑移关系统一为一个模型。提出了两种与两种类型的破坏模式相对应的破坏准则，即混凝土压碎和中间裂纹（IC）引起的脱胶。通过理论模型，获得并预测了在湿热环境下CFRP加固的RC梁的挠曲挠度，界面剪切应力分布和极限荷载。此外，理论模型得到了测试结果的验证。结果表明，湿热环境对CFRP-混凝土界面行为有重大影响。与未进行湿热环境预处理的控制梁相比，加固RC梁的挠度和极限荷载分别降低了51.9％和20％。