Creep and recovery behavior characterization of asphalt mixture in compression

A simplified Schapery’s nonlinear viscoelastic model and a modified Schwartz’s viscoplastic model with a proposed stress function are combined to characterize viscoelastic and viscoplastic behaviors of compressed asphalt mixture. In this combined model, the simplified Schapery’s model is used for describing the recoverable strain, and the modified Schwartz’s model is for the irrecoverable strain. The model parameters are determined with the multiple-stress repeated creep–recovery test and the one-hour creep test, and then the combined model is validated with some other tests, including the one-hour creep test at a different stress, the fixed-stress repeated creep–recovery test and the random loading test. Compared with the Perzyna’s viscoplastic model, the modified Schwartz’s model can fit the experimental viscoplastic strain response better in a wide stress range, so that the combined model can predict the creep and recovery behaviors of asphalt mixture under uniaxial compression well.