Visco-plastic behavior of bituminous mixtures: Experiments and modeling

Abstract

Behaviour of bituminous mixtures is very complex. Their rheological properties depend on strain amplitude level and temperature. We can observe linear viscoelasticity properties for very small strain amplitudes and non-linearities for larger strain level. Fatigue and rutting (permanent deformation) can appear for a great number of cycles. Moreover brittle or ductile failure can occur. All of these properties highly depend on temperature. The DBN (Di Benedetto-Neifar) model developed last years at LGCB-LTDS laboratory (University of Lyon/ENTPE “Ecole Nationale des TPE”) aims at describing the complex behaviour of bituminous mixtures with a unified formalism. The model is also versatile and may be adapted to take into account or not some specific properties of bituminous materials as failure mechanisms. First, equations of the DBNEPP (Elastic-Perfectly Plastic version of the DBN model) describing the whole three-dimensional DBN model in the linear and viscoplastic domains are recalled. Experiments made at LGCB-LTDS laboratory on bituminous mixtures in the large strain domain are then presented. Finally simulations are proposed based on the DBNEPP model in the viscoelastic and plastic domains.