Abstract:
This paper presents the development of a three-dimensional micromechanical
model based on the Laguerre-Voronoi diagrams of the grain structure to study the viscoelastic
behaviour of asphalt mastic with the use of the discrete element method (DEM).
Usually, the DEM models of asphalt mastics adopt a Burger's contact model to reproduce
the known viscoelastic behaviour. A generalized Kelvin chain model (GK) was developed
within a particle model (PM) framework in order to obtain a better agreement in the
determination of dynamic properties of mastics. Numerical cyclic tests under a frequency
range varying from 10 to 0.10 Hz were implemented to analyse the dynamic response.
The parameters of the DEM model are determined from macroscale material properties,
which are obtained by fitting lab-based dynamic modulus and phase angle results. The
influence of the parameters defining the contact models on the dynamic response was
investigated. An iterative procedure was derived to convert the macroscale properties
into calibrated contact parameters of the proposed model. Simulation tests show a good
correlation between the numerical results obtained with the GK contact model and the
experimental data when compared with the agreement obtained with the Burger's model.