Title: Bonding Behavior and Interfacial Damage between Steel Fiber-Reinforced Concrete and Steel

Author(s): Kai Wu, Jianan Xu, Feng Chen, Chuyang Chen, and Zhigang Chai

Publication: Materials Journal

Volume: 118

Issue: 2

Appears on pages(s): 83-96

Keywords: bond-slip curve; bonding strength; energy dissipation; interfacial damage; pushout test; steel fiber-reinforced concrete (SFRC)-encased steel column

DOI: 10.14359/51730413

Date: 3/1/2021

Abstract:
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 (ρsf) (0, 1, 2, and 3%), thickness of concrete cover (Css), and effective bonding length (Le) 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 ρsf has a stronger constraint effect on concrete cracks, which leads to better post-peak bonding behavior. A bigger Css can delay the interfacial damage in the middle and late stages of the test. A larger Le means more elastic deformation energy can be stored at the interface, so the damage variable increases at a slower pace.