Size effect regarding fatigue evaluation of asphalt mixtures - Laboratory cantilever bending tests

Experimental results for fatigue tests on three size geometrically similar asphalt concrete specimen are presented. Effect on fatigue life is analyzed and compared to trends given by a fatigue damage model. This innovative laboratory campaign points out a size effect on fatigue assessment of asphalt mixture. In a second part, the application of a nonlocal fatigue damage model for asphalt mixtures is presented. A qualitative agreement is obtained between experimental results and non local damage fatigue predictions trends. This agreement validates the nonlocal modelling that allows to model the influence of the heterogeneous nature of the material on fatigue failure. Differences observed between laboratory data and model predictions may be attributed to viscoelasticity induced thermal softening which had to be quantified and coupled to damage in order to properly study these fatigue test data.