Bonding Behavior And Interfacial Damage Between Steel Fiber-Reinforced Concrete And Steel

The reinforcing bar cages in concrete-encased steel (CES) structures are replaced with steel fibers to form the steel fiber-reinforced concrete-encased steel (SFRCES) structures, which can avoid common difficulties in the construction of a traditional CES structure. To study the bonding properties and interfacial damage between shaped steel and steel fiber-reinforced concrete (SFRC), the pushout tests of 16 specimens were conducted. Main parameters including steel fiber ratio (rho(sf)) (0, 1, 2, and 3%), thickness of concrete cover (C-ss), and effective bonding length (L-e) of specimens were considered. In this paper, some important performance indicators are obtained, such as P-S curves, bonding strength, interfacial energy dissipation, and interfacial damage variables. The experimental results show that the P-S curves at the loading end and free end have the greatest difference under the peak load. A higher rho(sf) has a stronger constraint effect on concrete cracks, which leads to better post-peak bonding behavior. A bigger C-ss can delay the interfacial damage in the middle and late stages of the test. A larger L-e means more elastic deformation energy can be stored at the interface, so the damage variable increases at a slower pace.