Comparison of fatigue test methods on asphalt mastic

Fatigue failure is one of the major distresses for asphalt pavements at intermediate temperatures. Accurate assessment of fatigue properties of asphalt mastic is of great importance for ensuring satisfactory performance and the structural integrity of asphalt pavements. In this paper, Linear Amplitude Sweep and Time Sweep tests in strain controlled mode are performed on two different asphalt mastics using the Dynamic Shear Rheometer. A comparison between the two methods is presented, and the experimental results are analysed based on the viscoelastic continuum damage theory. The fatigue life, Nf, obtained from the two test procedures returns significantly different values. This is most likely associated to the type of failure induced by the two diverse loading modes, which is visualized in the specific crack growth patterns. Therefore, the LAS test should be intended as relative tolerance tests for damage rather than an effective fatigue test.