Fatigue behavior of ballastless track concrete in high-speed railways under different operating speeds

Abstract This study investigates the influence of loading frequency on the fatigue behavior of ballastless track concrete for high-speed railways, aiming to support the development of concrete capable of withstanding higher operational speeds. Fatigue tests were conducted at loading frequencies ranging from 5 to 40 Hz, with a focus on fatigue life, damage evolution, energy dissipation, and residual fatigue strain in the concrete. The results indicate that between 5 and 15 Hz, the fatigue life and energy dissipation remain relatively stable, with minimal damage evolution and small residual strains. As the frequency increases to 15–20 Hz, the fatigue life and energy dissipation gradually decrease, while damage accumulation and residual strain increase. Beyond 20 Hz, both fatigue life and energy dissipation decrease rapidly, damage accumulation becomes more pronounced, and residual strain continues to rise. These phenomena are primarily attributed to the increased strain rate and load change rate at higher frequencies, which affect the microstructure evolution and lead to reduced fatigue performance.