Modelling of Flexible Pavements with Thin Bituminous Surfacing – Using Linear Elastic Theory and Finite Element Method

Abstract

Flexible road pavements are important transport infrastructure in Australia for providing an all weather road network for a population of 22 million people with land size of about 7 million square kilometres. Between the surfacing types, sprayed seal and thin asphalt are most commonly used by State and Local Governments for rural road construction. Asphalt fatigue and subgrade deformation from repeated loading over time are the most common failure mechanisms and these in turn are the major attributors to the pavement maintenance and rehabilitation cost. Thin surfacing pavements with a weak road base and foundation often exhibit plastic deformation in the base and subgrade layers. Linear Elastic Theory (LET) and Finite Element Method (FEM) based numerical analyses have been widely used in research to develop pavement models and replicate realistic vehicular loadings. The thin surfacing pavement is modelled using LET and FEM with three-dimensional (3D) ideal elastic layered system and two-dimensional (2D) axisymmetrical elements, respectively. The vertical displacements at the top of the asphalt layer are determined using both LET and FEM and the findings compared to the measured field data. Results show that the deflections generated by the FEM are in closer agreement with the field data. At a horizontal distance of 700 to 1500mm from the loading significant displacement variances from the field data are found for both LET and FEM.