Study on deformation behavior and prediction model of asphalt mixture based on interface-slip characteristics of aggregates

•A comprehensive micromechanical parameter Rswas calculated to evaluate the interface-slip characteristic of aggregates.•The deformation behavior and mechanism of asphalt mixture were analyzed from the perspective of aggregate contact and slip.•The deformation process of asphalt mixture can be divided into three stages.•The prediction model of asphalt mixture based on the interface-slip characteristics of aggregates was established. Asphalt mixture is a granular material with viscoelasticity, and its deformation behavior is closely related to the interface characteristics of aggregates. To further studying the deformation behavior of asphalt mixture, the interface-slip characteristics of asphalt mixture were analyzed with self-developed tester. Rs is the ratio of the actual loads to the contact-slip resistance capacity of aggregates, which was proposed to evaluate the interface-slip characteristics of aggregates and predict the deformation behavior of asphalt mixture. The prediction model of deformation was established by analysis of contributing factors, model parameters fitting and model validation. The results indicate that Rscan accurately express the contact-slip characteristic of aggregates. The permanent deformation is mainly caused by the slip-deformation of aggregate particles, and the deformation process can be divided into three stages of rapid growth, fluctuation, and stability. The densification and displacement of flowing materials is the main reason for the rapid growth, the cycle of instability-reconstruction of skeleton causes the fluctuation of the deformation growth rate, and the boosted stability of the reconstructed skeleton keeps the deformation growth rate low and stable. Further research show that the tangential contact particles are the primary factor causing the slip-deformation. And asphalt is a lubricant for particles from contact stable state to metastable state and then to an unstable state, which mainly depends on the temperature, the quantity of free asphalt, and the previous contact state of particles. Moreover, the prediction model based on the interface-slip characteristics of aggregates can effectively predict the permanent deformation of asphalt mixture.