MULTISCALEVISCOELASTIC-VISCOPLASTIC MODEL FOR THE PREDICTION OF PERMANENT DEFORMATION IN FLEXIBLE PAVEMENTS

摘要

Creep/relaxation of asphalt consisting of the thermorheological binder material (bitumen), inclusions (aggregates), and air voids may lead to considerable permanent deformations (rutting). Although viscoelastic models are suitable to describe the asphalt behavior at low stress levels and in the low-temperature regime, material models taking plastic deformation into account are needed in order to capture the thermorheological behavior of asphalt at elevated temperature regimes. In this paper, the deformation behavior of asphalt is described by means of a creep/relaxation function, which, in a second step, is extended toward viscoplastic deformation. The underlying model parameters describing the thermorheological nature of asphalt are determined from a multiscale model considering five observation scales. The model, implemented into a Finite Element program, is used for determination of permanent deformations, as illustrated by the reanalysis of triaxial cyclic compression tests and the prediction of rutting inflexible pavements.