Effect of steel fiber content on fatigue performance of high-strength concrete beams

This study focuses on the fatigue performance of steel fiber reinforced high-strength concrete structures. The effect of steel fiber volume fraction (0%, 0.5%, 1.0%, 1.5%) on the cracking resistance, deformation characteristics and fatigue life of high-strength concrete beams under fatigue loading were systematically investigated through equal-amplitude fatigue tests on four beam specimens. The results show that the incorporation of steel fibers can significantly improve the crack resistance of concrete, which is manifested in the reduction of crack width by 35-121%. Meanwhile, the steel fibers can effectively inhibit the development of deflection of beams during fatigue loading, slow down the rate of stiffness degradation. The incorporation of steel fibers reduced the mid-span deflection of the beams by 15-61% and increased the fatigue life by 66.9-149.9%. Based on the experimental data, this study confirms that the steel fiber reinforcement technology is a practical and economically significant fatigue performance enhancement solution for high-strength concrete structures. This paper provides an important theoretical basis and technical support for the engineering application of steel fiber reinforced high-strength concrete structures in complex loading environments.