Investigating the friction and wear performance of SBS-modified asphalt pavement under bump distress and water exposure

This study investigates the long-term friction performance evolution of AC-13 graded SBS-modified asphalt pavement under combined bump distress and water environment. Using a self-developed cyclic friction test system, fatigue wear characteristics of base pavement and pavement with bump distress were compared under ambient temperature and aqueous solution conditions. Results show that water substantially accelerates friction deterioration. After 50 cycles, the total friction attenuation rate relative to the initial value for the base pavement reached 17.9% under ambient conditions, with a stage attenuation of 4.2% from cycle 30 to cycle 50; in the aqueous solution, the total attenuation rate relative to the initial value was 15.4%, with a stage attenuation of 7.7% from cycle 30 to cycle 50. Pavements with bump distress exhibited faster performance loss in water: after 30 cycles, the total friction attenuation rates relative to the initial values for circular and trapezoidal bump distress were 5.2% and 7.4%, respectively, both higher than that of the base pavement without distress over the same period. Three-dimensional microscopic morphology analysis revealed that the surface roughness of the rubber slider decreased in water, reflecting the lubricating and scouring effects of the water medium. In contrast, under ambient conditions the rubber slider surface retained higher roughness, consistent with the higher friction forces observed. In summary, the combined effect of water environment and bump distress significantly exacerbates skid resistance degradation of asphalt pavement. These findings provide valuable references for durability design and maintenance decision-making of asphalt pavements in humid and water-prone environments.