Numerical finite element formulation of the 3D linear viscoelastic material model: Complex Poisson's ratio of bituminous mixtures

Poisson's ratio in asphalt mixture is a time dependent (in time domain) or a complex frequency dependent quantity (in the frequency domain). This paper develops a 3D linear viscoelastic formulation in order to characterize the dynamic modulus (E*) and complex Poisson's ratio (v*) of mixtures. Under the hypothesis of isotropy, two complex moduli, the shear (G*) and bulk moduli (K*) are necessary to determine the dynamic Young's modulus and complex Poisson's ratio. The proposed model is implemented in the Cats3M finite element package. A systematic procedure for identifying the model parameters is discussed. Finally, the model is validated by comparing the model predictions with experimental data on asphalt mixture. This comparison shows that the presented constitutive model is able of predicting the 3D linear behaviour of asphalt mixtures.