Unified Characterization of Rubber Asphalt Mixture Strength under Different Stress Loading Paths

The research on the strength characteristics of rubberized asphalt pavement materials could provide calculation parameters for structural resistance design. However, the strength results of different methods varied significantly, potentially significantly affecting the structural resistance design. Therefore, for the purpose of overcoming the design deviation caused by the randomness of the laboratory strength, three different tests of unconfined compressive strength, splitting strength, and direct tensile strength were carried out at various loading speeds and test temperatures. The time-temperature properties of the strength under diverse stress loading paths were compared, and the characterization model of rubber asphalt mixture strength was proposed by a dimensionless method. The results showed that loading speed and temperature significantly affect the strength of the rubber asphalt mixture. In the three different tests, the unconfined compressive strength was much larger than the other strength, and the splitting strength was the smallest. The speed sensitivity of direct tensile strength was the highest, while that of unconfined compressive strength was the lowest. With the temperature rising, the speed sensitivity of strength decreased. The power function could express the speed correlation of strength, and the quadratic polynomial function could express the temperature dependence of strength. In addition, the linear model could describe the strength master curve well. The unified strength characterization model of rubber asphalt mixture considered the impact of stress loading path and material viscoelasticity. The research could improve the efficiency of obtaining pavement materials’ damage resistance and the structural resistance’s design accuracy, so as to improve the durability of asphalt pavement, and play a role in promoting the application of rubber asphalt materials.