Abstract:In order to reveal the influence of salt erosion and freeze-thaw cycle coupling effect of steel fiber on concrete damage evolution, four groups of concrete specimens with different mass fraction of steel fiber were tested under salt freeze-thaw test. The damage of concrete after salt freeze-thaw cycles was analyzed by ultrasonic method and laser scanning method. The damage degree D of concrete after salt freeze-thaw cycles was obtained by analyzing the change of ultrasonic wave velocity. The Weibull distribution model between D and freeze-thaw cycles n was established. The surface roughness was used to characterize the surface damage of the concrete. The change rate of roughness ΔR of concrete with different steel fiber dosage was studied as a function of freeze-thaw cycles n. The results indicate that the damage of concrete decreases with the increase of steel fiber dosage. The relationship between D and n established by ultrasonic method satisfied the two-parameter Weibull distribution model, and the determination coefficient is higher than 0.95. It has an exponential relationship between D and ΔR due to its determination coefficient higher than 0.8.