Long-Term Water Stability of Hydraulic Asphalt Concrete Based on Time–Temperature Equivalence

To analyze the long-term water stability of hydraulic asphalt concrete, the bending test, splitting test, and uniaxial compression test of asphalt concrete immersed at 20°C, 40°C, 60°C, and 80°C for different durations were conducted, and attenuation models for the bending strain, splitting tensile strength, and compressive strength of asphalt concrete under long-term immersion conditions were established based on the time–temperature equivalence principle. The results show that, at different temperatures, the bending strain, splitting tensile strength, and compressive strength of asphalt concrete decreased with the increase of water immersion time. The bending strain, splitting tensile strength, and compressive strength stabilized under long-term immersion at 80°C. The water stability of asphalt concrete during immersion can be analyzed quantitatively using the attenuation models and water stability coefficient. The water stability of hydraulic asphalt concrete tends to be constant under long-term immersion conditions. The sensitivity of the asphalt concrete performance indicators for water damage is in the order bending strain > splitting tensile strength > compressive strength. The long-term water stability of hydraulic asphalt concrete should be comprehensively analyzed by calculating the water stability coefficient using compressive strength, splitting tensile strength, and bending strain. The research results can provide new ideas for the quantitative analysis of long-term water stability of hydraulic asphalt concrete.