The difficulties of developing an authoritative model of predicting the fatigue behaviour of bituminous road pavements are described; all proposed systems exhibit fundamental weaknesses and require calibration against actual pavement behaviour. A computer program has been developed to analyse fatigue behaviour under different spectra of traffic loading applied under representative spectra of pavement temperatures and temperature gradients within the pavement. The influence of these parameters on the fatigue behaviour of a range of thicknesses of bituminous pavements is described: alternative fatigue criteria are adopted in the analyses. The relation between fatigue damage and the magnitude of the wheel-load cannot be approximated to a simple power law and an alternative approach is suggested. The importance of pavement temperature and temperature gradient is shown to depend on the form of the fatigue criterion adopted. Assumptions about the contact area of tyres are likely to be less important. (Author/publisher)
Abstract