Research on the Fracture Behavior of Steel-Fiber-Reinforced High-Strength Concrete

The behavior of steel fiber concrete, which is the most widely used building material, has been widely examined. However, methods for calculating Fracture parameters differ by fracture behavior of SFHSC with different strengths. In this study, the fracture behavior of steel-fiber-reinforced high-strength concrete (SFHSC) was -investigated using three-point bending tests. A total of 144 notched concrete beams with a size of 100 mm × 100 mm × 515 mm were tested for three-point bending in 26 groups. The effects of the steel fiber volume ratio, steel fiber type, and relative notch depth on the fracture toughness (K(IC)) and fracture energy (G(F)) of SFHSC specimens were studied. The results show that an increase in the volume fraction of steel fiber (ρ(f)) added to high-strength concrete (HSC) significantly improves the fracture behavior of HSC. As compared to milled and sheared corrugated steel fibers, cut bow steel fibers significantly improve the fracture behavior of SFHSC. The effect of incision depth changes on the K(IC) and G(F) of SFHSC and HSC for the comparison group has no common characteristics. With an increase in incision depth, the values of K(IC) of the SFHSC specimens decrease slightly. The G(F0.5)/G(F0.4) of the SFHSC specimens show a decreasing trend with an increase in ρ(f). According to the test results, we propose calculation models for the fracture behavior of SFHSC with different strengths. Thus, we present a convenient and accurate method to calculate fracture parameters, which lays a foundation for subsequent research.