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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.

Asphalt and filler interaction plays a key role on the performances of asphalt mastics and mixtures, while the asphalt and filler interaction ability is in turn affected by the material characteristics. In order to analyse the effects of material characteristics on asphalt and filler interaction, two kinds of matrix asphalt binders and three kinds of fillers were used to prepare asphalt mastics with different filler volume fractions. The dynamic shear rheological properties of these asphalt mastics were measured. The evaluation index K–B–G* was calculated subsequently to analyse the effects of material characteristics on the asphalt and filler interaction ability. The results show that filler volume fraction, filler particle size, SiO2 content and asphalt components had various levels of effects on the asphalt and filler interaction ability. Variance analysis was then conducted to rank these influencing factors from high to low as: (1) filler particle size, (2) asphaltene and resins content, (3) f...

A reliable UMAT subroutine of selected constitutive model of asphalt mixture is developed and applied to characterize the three-stage rutting behavior of asphalt pavement by using ABAQUS. It is indicated that the heavier traffic load not only induces the greater rutting depth, but also accelerates the rutting rate, causing the pavement earlier enter into rutting failure with shortened service life. The damage evolution and axle-load conversion are further discussed. Results show that the pavement subjected to heavier axle loads has the greater damage and faster damage evolution. The axle-load conversion index is 5.97 according to rut equivalence principle.