A modified HS model: Numerical applications in modeling the response of bituminous materials

This paper presents numerical application of a modified Huet-Sayegh (MHS) model for modeling the response of bituminous materials. The model consists of elastic, viscoelastic and viscous response elements. Application of the model for describing the frequency domain response of bituminous materials is presented. To utilize the model for time domain use, a numerical approach is proposed. The proposed numerical approach utilizes the Grünwald Letnikov definition of fractional derivatives. The formulation is first discussed for one dimensional case, and then generalized into three dimensional forms by decoupling the deformation into deviatoric and volumetric components. The 3D formulation is finally implemented into a commercially available strain-controlled finite element program, ABAQUS. For this purpose, a user material subroutine (UMAT) code has been scripted in FORTRAN language. After performing various simulations to verify the UMAT code, application of the material model in performing meso-mechanistic computations for porous asphalt layer is presented. Simulation results are used to illustrate the significance of the linear dashpot in the MHS model. Moreover, results that were obtained from the UMAT code are compared with corresponding results obtained with the built-in material model in ABAQUS. Good agreement in results has been observed. The results have demonstrated the model accuracy and the suitability of the proposed numerical approach to allow the model use in finite element environments.

► The original Huet–Sayegh model is modified. ► Using the Grünwald Letnikov definition for fractional derivatives numerical implementation of MHS is presented. ► Application in meso-mechanistic simulations for porous asphalt is presented.