Use of the Distinct Element Method to Model the Deformation Behavior of an Idealized Asphalt Mixture

Abstract

This paper investigates the use of distinct element modelling to simulate the behavior of a highly idealized bituminous mixture in an uniaxial compressive creep test. The effect of bitumen is represented as shear and normal contact stiffnesses. Elastic contact properties have been used to investigate the effect of sample size and the effect of the values of the shear and normal contact stiffnesses on bulk material properties. It was found that a sample containing at least 4,500 particles is required for Young's modulus and Poisson's ratio to be within 2% of the values calculated using a much larger number of particles. The bulk modulus was found to be linearly dependent on the normal contact stiffness and independent of the shear contact stiffness. Poisson's ratio was found to be dependent on only the ratio of the shear contact stiffness to the normal contact stiffness. A simple elasto-visco-plastic Burger's model was introduced to give time dependent shear and normal contact stiffnesses.

Keywords:

• Distinct element modelling
• Asphalt
• Shear contact stiffness
• Normal contact stiffness

Acknowledgements

The authors' are grateful to the Nottingham Asphalt Research Consortium (NARC) for providing research funding.