Analysis of Bonding Slip Performance Between Novel Epoxy Resin Concrete and Reinforcement

This study systematically investigated the bonding behavior between novel epoxy resin concrete (ERC) and ribbed HRB400 steel bars through central pull-out tests. A total of 30 groups of specimens were designed to evaluate the effects of concrete strength, concrete cover thickness, bar diameter, anchorage length, and stirrup ratio on bond performance. The results indicate that increasing ERC strength significantly enhances the bond with reinforcement, primarily by improving chemical adhesion and mechanical interlock, while inhibiting the development of internal cracks. Concrete cover thickness was found to have a significant impact on bond strength; increasing the cover within a reasonable range effectively prevented splitting failure. Enlarging the bar diameter from 16 mm to 20 mm improved bond strength, but the benefit diminished beyond 20 mm. A negative correlation was observed between anchorage length and ultimate bond strength. Bond stress was unevenly distributed along the anchorage length, with higher stresses at both ends and lower stress in the middle region. Compared with conventional concrete of equivalent grade, the bond performance between ERC and steel bars was improved by 79%. These findings provide a theoretical basis for the design and application of ERC in engineering structures.