Dynamic viscoelastic response of an instrumented asphalt pavement under various axles with non-uniform stress distribution

This paper is presented to analyse the instrumented asphalt pavement responses with infinite element boundaries under moving non-uniform distribution tyre–pavement contact stresses. The 3-D finite element model and implicit dynamic analysis were used to simulate the instrumented pavement. The asphalt layer was modelled as a viscoelastic material and the Prony series was used in the viscoelastic material model. The viscoelastic parameters were obtained from creep compliance experiments at various temperatures and converted to relaxation parameters. The interface binding conditions between asphalt layers were analysed and determined from field measurements. A non-traditional loading assumption was used to represent the non-uniform distribution of tyre–pavement contact stresses along longitudinal and transverse directions. It was found that the asphalt layers were not well bonded, which may result from thermal conditions in the pavement. With infinite element boundaries and moving non-uniform stress distribution, the pavement responses obtained by calculations and measurements under different vehicle loading conditions (vehicle with two single axles and vehicle with a single axle plus a tandem axle) were compared and its characteristics were analysed. Good agreements were achieved. The critical responses under different loading conditions such as strains at the bottom of the asphalt binder course and asphalt base course obtained from both calculations and measurements were identified. The results also show that the strain interference effect is significant between axles and this effect is more serious as the pavement depth increases.