Numerical Investigation of the Bond–Slip Mechanism Between Deformed CFRP Bars and Ultra-High Performance Concrete

To further investigate the bond behavior between carbon fiber-reinforced polymer (CFRP) bars and ultra-high-performance concrete (UHPC) under monotonic loading, a finite element model was established in ABAQUS based on existing experimental data. The material parameters, constitutive models, and interface contact definitions were verified through numerical simulation. Utilizing this modeling strategy, 36 center-pull finite element models with dimensions of 150 mm × 150 mm × 150 mm were analyzed. By systematically varying the geometric parameters of the CFRP bars, the effects of surface configuration, bar diameter, and rib spacing on the bond performance between CFRP bars and UHPC were analyzed. The results demonstrate that uniform-ribbed bars exhibit the highest bond performance, followed by helical-ribbed bars, whereas dented-ribbed bars show the lowest bond strength. The ultimate bond strength decreases with increasing bar diameter. For uniform-ribbed bars, the optimal rib spacing is 1.2D (where D is the bar diameter), resulting in the highest peak bond strength.