A Simplified Practical Procedure for Estimation of Fatigue and Crack Growth Characteristics of Asphaltic Mixes

This paper describes a simplified procedure for estimation of fatigue and crack growth characteristics of asphaltic mixes. The procedure requires the determination of the so-called master curve(s), the asphalt properties and the mix composition. It is shown that the master curve does not only give information about the variation of the mix stiffness, the loading time and the temperature, but also on the fatigue behaviour of asphaltic mixes. This information can reliably be obtained from rather simple tests, which can be performed in many road-engineering laboratories. In the proposed procedure it is possible to choose between the Wöhler approach and the more fundamental fracture mechanics approach. Procedures of determining the fatigue characteristics of asphaltic mixes from simple tests are of special interest in mix design procedures where the quality of various mixes with respect to fatigue and crack resistance has to be evaluated. It is obvious that such a procedure is also extremely attractive for specification and pavement evaluation purposes. An insight is provided as to how the fatigue parameters for an asphaltic mix can be estimated using the Wöhler approach and the fracture mechanics approach.