Abstract:

Virtual fatigue tests of the small beam specimen from asphalt mixture(AM) were performed using the discrete element method(DEM) to investigate the fatigue mechanism of AM microscopically. A gradation derivation formula was established by the probability theory to convert the volumetric aggregate gradation into the twodimensional(2D) digital speciment quantity gradation. Taking the irregular form of the aggregate into account, a generation program of the virtual structure of the 2D digital specimen was compiled based on MonteCarlo method and the specimens were generated. A whole package of virtual fatigue test methods of AM, including the establishment of DEM model of AM, the selection of the contact modes of the discrete elements, and the criteria judging the fatigue failure, was established based on DEM. The fatigue tests of the small beam from AM were performed, and their results were compared with those of its virtual fatigue tests based on DEM. Their good agreement implicated that the proposed virtual 2D beam fatigue test based on DEM can predict well the fatigue life of AM. The virtual beam fatigue test can be used as an auxiliary means to evaluate the fatigue performance of AM.

Key words: road engineering, asphalt mixture(AM), fatigue performance, virtual fatigue test, discrete element method(DEM)