Asphalt pavements on steep slope sections in regions with seasonal freezing are affected by loads and the environment, and the shear resistance and shear fatigue performance attenuation of interlayer adhesive materials become increasingly severe. To study the effect of freeze–thaw cycles on shear fatigue resistance of asphalt pavement interlayer adhesive materials, an asphalt pavement interlayer shear fatigue test device was designed and self-assembled. The ultimate shear strength test of asphalt mixtures was determined using a universal testing machine. The interlayer shear fatigue of asphalt mixtures was tested, and the single factor analysis of shear stress ratio, loading frequency, temperature, and freeze–thaw cycle influence on the interlayer shear fatigue were discussed. The frequency, temperature, freeze–thaw cycles, and practical application parameters were corrected based on a prediction model for shear fatigue life under different shear stress levels, and a prediction model for interlayer shear fatigue life was established. The results show that the shear fatigue failure life of the same adhesive layer specimen decreases with the increase of the stress ratio, and is very sensitive to changes in the stress level. Furthermore, shear fatigue failure life and the stress level are related linearly in double logarithmic coordinates. The interlayer shear fatigue failure life and loading frequency have an exponential change trend. The higher the loading frequency, the greater is the shear fatigue failure between layers of asphalt pavement. The interlayer shear fatigue failure life of the different types of specimens decreases with the increase of the number of freeze–thaw cycles, and has a linear trend. The study results can provide a theoretical basis and technical support for asphalt pavement material selection and structural design on steep slopes in regions with seasonal freezing.

In seasonal frozen soil areas, the repeated freeze–thaw cycle of internal moisture in asphalt mixture in winter and spring will accelerate the peeling of asphalt film and aggravate the water damage of asphalt pavement. It is of great significance to carry out the attenuation law of mechanical properties of asphalt mixture under freeze–thaw cycles to prevent and reduce the economic losses caused by water damage to asphalt pavement. This study will investigate the impact of deicer application on the water stability of asphalt mixtures within the climatic conditions prevalent in Northwest China. Specifically, freeze–thaw cycle tests were administered to two types of dense-graded asphalt mixtures under three distinct deicer solutions and three disparate low-temperature environments. The Marshall water immersion test and freeze–thaw splitting test were employed to evaluate the water stability of asphalt mixtures subject to multiple factors, and the relative importance of each factor was statistically analyzed using the acquired data. Results demonstrated that AC-13 and AC-16 asphalt mixtures (AC is asphalt-concrete, which is asphalt concrete, and 13 or 16 represents the maximum particle size of aggregate (13 mm or 16 mm)), saturated in 15% CH₄N₂O, 20% NaCl, and 20% CH₂CH₃OH solutions, underwent a varying number of freezing–thawing cycles (0, 5, 10, 15, 20, 25, and 30) at temperatures of −5 °C, −15 °C, and −25 °C, respectively, displayed a discernible decline in their residual stability MS₀ and freeze–thaw splitting tensile strength ratio TSR. This decline was particularly marked when temperatures dropped below the solution’s freezing point. Disregarding the fixed factors of weather variation (different low-temperature environments) and road service duration (number of freezing–thawing cycles), the aggregate grading imposed a more pronounced influence on asphalt mixture water stability than the presence of deicers.