A multi-linear fatigue life model of flexible pavements under multiple axle loadings

Abstract

The fatigue damage of a pavement under repeated traffic loadings is a key issue for pavement design. At the material scale, the fatigue performance of asphalt mixtures can be assessed with laboratory tests. The standard fatigue test consists of the application of a continuous sinusoidal signal on the specimens and enables to write the fatigue life as a function of the strain level. Real loadings are more complex. Additional parameters may therefore have an influence on the fatigue life of bituminous mixtures. A methodology for a better calculation of the fatigue life of asphalt pavements is developed. It couples a structural approach and a material-based approach. This paper presents the material-based approach of the methodology. A database of laboratory fatigue tests with complex loadings has been built. An experimental plan whose variables are the independent shape parameters characterising a loading signal is defined and the synthetic complex loading signals constructed. The results of the fatigue tests enabled the calibration of a multi-linear fatigue model where the fatigue life is a function of the independent shape parameters characterizing the loading signal. Coupling the multi-linear fatigue model with a pavement model enables the calculation of the fatigue life of a pavement under different loading conditions. © RILEM 2012.