## 1 Introduction  
Rutting is one of the main diseases of asphalt pavement, and it is also a key design index in the structural design of asphalt pavement in many countries such as: the American Mechanistic-Empirical Pavement Design Guide (MEPDG) [1], the Shell Pavement Design Manual [2], China's Specifications for Design of Highway Asphalt Pavement [3], etc. ; all control the structural design through the allowable rutting deformation within the design life. In these design methods, the rutting performance prediction model is mainly used to predict the rutting deformation of the asphalt concrete structure at the end of the design life, and through structural combination and material performance optimization, the rutting deformation at the end of the design life is less than the allowable value, so as to ensure the rationality of pavement structure design. It can be seen that how to ensure the accuracy and reliability of the rutting performance prediction model is one of the key issues of these design methods. The core basis of the rutting performance prediction model is the conversion relationship between the permanent strain accumulation of the laboratory repeated load test and the actual road rutting accumulation [4, 5]. At present, two methods are mainly used to establish the rutting performance prediction model. The first is the layered strain method [6; 7; 8; 9; 10; 11], which combines the mechanical analysis of pavement structure, material performance tests, and actual rutting measurement results of pavement structures, and predicts the rutting deformation according to the layered strain accumulation method. For example, in the MEPDG research [12], [PERSON] [13; 14] first established the relationship between the permanent strain of each layered asphalt mixture and the number of loading times. Then 387 sets of observation data from 88 LTPP observation sections in 28 states were used to calibrate and verify the relationship, and finally the prediction model for asphalt layer rutting performance [1] was obtained. As for China's Specifications [3], considering the difference of stress distribution at different depths of asphalt pavement and the rutting resistance performance of different layers, the permanent deformation is calculated layer by layer, and based on 229 rutting test results of various asphalt mixtures, a rutting performance model based on the layered strain accumulation method was established, and the model was revised and verified using the rutting data of more than 10 highways and 5 test sections [5]. The Shell Pavement Design Manual [2] uses simplified linear elastic stress analysis and laboratory static load creep tests without confining pressure to establish a model for predicting the permanent deformation of the asphalt layer. The model considers the thickness of the asphalt layer, the average stress in the layer, and the asphalt concrete stiffness, which could compare the resistance to permanent deformation of different asphalt mixtures. [PERSON] [15] introduced the generalized stiffness modulus of the viscosity part of the asphalt layer on the basis of the Shell model, and [PERSON] and [PERSON] [10] suggested to directly use the asphalt mixture stiffness from the static load creep test under given load stress and temperature conditions, further optimizing the Shell model's rutting estimation equation. [PERSON], [PERSON], and [PERSON] et al. [16] established a rutting model considering the intermittent time of load action. [PERSON] et al. [17] established a high-grade asphalt pavement rutting prediction model by using the elastic layered system theory combined with the rheological model of asphalt mixture. [PERSON] [18] considered that the permanent deformation depends on parameters such as stress, loading time, and temperature, and assumed that the viscoelastic deformation of the asphalt mixture had sufficient recovery time within the load interval, and established a corresponding rutting model accordingly.