Laboratory development of a constitutive model for visco-elasto-plastic materials

Test method and data analysis procedures are presented in order to develop a constitutive model which can describe the behavior of visco-elasto-plastic materials due to the external load. A series of creep tests were performed on asphalt concrete. It is shown that the elastic, plastic, viscoelastic and viscoplastic strain components are incorporated and present simultaneously in the total creep strain during the loading process. Elastic and plastic strains of the tested material are linearly proportional to the stress level. The Burger’s model and the Bingham’s model are employed to represent the viscoelastic and viscoplastic response, respectively. Model parameters are extracted from a series of uniaxial compression creep/recovery tests. A good agreement was observed between the verification test result and the prediction from the model.