Simulation of cyclic loading tests for asphalt mixtures using user defined models within discrete element method

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Conference Proceeding

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This paper presents a newly developed model for the simulation of a cyclic loading test (i.e., dynamic modulus test) of asphalt mixtures using user defined material models in the discrete element (DE) method. The DE model was prepared based on a random polygon algorithm instead of the image analysis technique commonly and usually used by many researchers. With this algorithm, the polygonal particles (i.e., aggregates) were created to present aggregates shape and size, and discrete elements (disks or balls) were bonded together with the viscoelastic model to simulate mastics (i.e., asphalt binder mixed with fines). In order to build the constitutive model, four contact models were employed in the asphalt mixture composite including the slip model, linear stiffness-contact model, contact-bond model and Burger's contact model. Lab tests of aggregates and mastics were conducted under dynamic loads to provide the input parameters for DE models of asphalt mixtures. The dynamic modulus and phase angles were measured in the lab were used to calibrate the micro parameters for the DE models so that the micro parameters reflected the viscoelastic behavior of the asphalt mastic. Then, the dynamic moduli of asphalt mixtures (coarse aggregates plus asphalt mastic) were predicted by conducting DE simulation under a cyclic loading algorithm to reflect the viscoelastic behavior of the mixture. The simulation results are very promising when compared the predicted and measured dynamic moduli and the phase angles. Copyright ASCE 2008.

Publication Title

Geotechnical Special Publication