Research on vehicle-asphalt pavement interaction and microstructure by
discrete element method
Abstract
The early damage of asphalt pavement is closely related to the
mechanical behavior of asphalt mixture. In order to study the mechanical
response of asphalt mixture particles under vehicle load, a 2 DOF 1/4
vehicle model composed of mass block-spring-damper was constructed in
this paper. Based on the discrete element theory, a three-dimensional
discrete element model of asphalt pavement with random distribution of
coarse aggregate was constructed according to material gradation and
porosity. The dynamic load of vehicle on the road surface was solved by
using road roughness as excitation. The constitutive relation between
particles was described by parallel bond and linear bond. The
microstructure parameters of each structure layer were obtained by trial
and error method. The “fish” language program was written to realize
vehicle load movement. Finally, the mechanical response and velocity of
the pavement structure layer particles were solved. The results show
that the vertical displacement of the pavement calculated by the
discrete element method is less than 8.9% of that calculated by the
finite element method, which indicates that the discrete element method
is more feasible. The vertical compressive stress of the upper layer is
14.1% higher than that of the middle layer, 57.7% higher than that of
the lower layer, and 80% higher than that of the base layer. The
longitudinal compressive stress of the upper layer is 64.3% greater
than that of the upper layer. The grain at the bottom of the middle
layer is mainly subjected to tensile stress. The particles in the upper
and middle layers mainly bear transverse compressive stress while the
other structural layers bear transverse tensile stress. The transverse,
longitudinal and vertical velocities of the upper layer particles vary
dramatically during vehicle startup and braking. When the vehicle is
running stably, the particle velocity of each structure layer is small.
The lateral and vertical velocity curves of the particles are
antisymmetric, while the longitudinal velocity curves of the particles
are symmetric.