Abstract:
Most low-traffic roads are primarily thin chip seal surfacing with an unbound granular base and
subgrades layers. This paper describes the development of a 3-D numerical model of a low-traffic road. The
numerical model was built using the finite element modelling. A 3-D chip seal surface was constructed using Xray
tomography scans of multiple layer seal samples removed from a road. Stones particles were modelled as rigid
body; the bitumen was modelled as deformable using a viscoelastic constitutive model. A stress dependent
nonlinear anisotropic material model was used for the granular base and subgrade. The material parameters for
the bitumen and granular layers are estimated using inverse modelling technique from experimental
measurements. The inverse model is formulated as a non-linear least squares minimization problem coupled
with a finite element model. It is done by constructing an iterative procedure using an optimisation routine in
MATLAB’s and at each iteration, finite element problem is solved.
