Characterizing Heterogeneity of Asphalt Mixture Based on Aggregate Particles Movements

In order to evaluate the movements characteristics of aggregate particles in asphalt mixture under loading and temperature effects and to study the heterogeneity of asphalt mixture, rutting tests were conducted. Firstly, AC-20, AC-25, SMA-20 and SMA-25 specimens with the baseline labeled on sections were selected to conduct rutting tests. Then the section images at different loading times and different temperature were handled by digital image processing to study the aggregate particle movement behavior by means of aggregate particle movement parameters. Finally, the asphalt mixture heterogeneity was analyzed by the defined heterogeneity area and homogeneity area. The results show that the longitudinal displacement of aggregates is significantly greater than the lateral displacement of aggregates under the standard axle load. The aggregate particles irregular movement area for gap-graded asphalt mixture is greater than dense-graded asphalt mixture at the same temperature and loading. And the temperature or loading increasing can lead to the increase of the heterogeneity area.