Experimental study on compressive properties of SFRC under high strain rate with different fiber content and aspect ratio

Abstract The dynamic mechanical properties of steel fiber reinforced concrete (SFRC) depend largely on the content and size of steel fibers. This paper presents an experimental study on mechanical properties of SFRC under high strain-rate compressive loading. In order to explore the co-effect of the fiber content and aspect ratio on the dynamic performance of SFRC, the SFRC specimens with three kinds of fiber aspect ratio (30, 50, 60, respectively) and six kinds of fiber content (0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5% in volume fraction) were tested by Split Hopkinson Pressure Bar (SHPB) device with a diameter of 75 mm. The test strain rate ranged from 30 s−1 to 370 s−1. Test results show that SFRC has obvious strain rate effect. With the same fiber aspect ratio, the optimum fiber content of SFRC shows strain rate sensitivity. And with the increase of fiber content, the dynamic increase factor (DIF) of SFRC decrease gradually. With the same fiber content, SFRC with a fiber aspect ratio of 50 shows the maximum compressive strength at different strain rates. In addition, the study also proposed the expression of DIF, strain rate and fiber content of SFRC to each fiber aspect ratio.