The bonding behavior between conventional concrete and Slurry Infiltrated Fiber Concrete (SIFCON) plays a critical role in enhancing the shear performance and ductility of composite structural members. This study investigates seven reinforced concrete specimens, divided into two groups in addition to a control sample made entirely of conventional concrete. The first group consisted of three composite beams combining conventional concrete and SIFCON, cast separately and connected through different interfacial geometries: rectangular, triangular, and semicircular. The second group replicated these specimens with the addition of 12 mm diameter bolts at the interface to improve bond strength. The results demonstrated that interface geometry significantly influences shear resistance and displacement behavior. Among the tested configurations, the rectangular interface achieved the highest performance, with a shear capacity increase of approximately 2.38 times compared to other shapes, along with improved stiffness and ductility. The inclusion of bolt reinforcement further enhanced load-carrying capacity, reaching about 1.6 times that of specimens without bolts. These specimens also exhibited larger displacements and interfacial slip prior to failure. However, despite the increased strength, bolt-reinforced specimens showed a more brittle and sudden failure mode, unlike the more gradual and ductile response observed in specimens with rectangular interfaces without bolts. The findings confirm that combining mechanical interlocking with anchorage systems can effectively improve shear strength and deformation capacity. Future research should focus on large-scale applications and long-term performance under cyclic and sustained loading conditions.
