Time–temperature equivalence property of asphalt mixture's compressive strength in triaxial stress state

Fatigue is a major form of distress in asphalt pavement, while the strength of asphalt mixture is a primary factor affecting fatigue; therefore, investigating the factors influencing asphalt mixture strength and their governing principles is an important foundation for research of the asphalt mixture fatigue. This work employed triaxial compression and uniaxial compression tests to investigate the strength of asphalt mixtures under different stress states, temperatures and loading rates and then established a master curve of asphalt mixture strength under various stress states using the time‒temperature superposition principle. The results showed that the asphalt mixture strength is significantly affected by the temperature and loading rate under any confining pressure, and this relationship can be described using the time‒temperature superposition principle. Additionally, the relationship between the confining pressure and asphalt mixture strength, as well as the parameters of the strength master curve and WLF equation, is linear. These findings can be used to predict asphalt mixture strength under different confining pressures, temperatures and loading rates, which will directly contribute to the research of asphalt mixture fatigue under these conditions.