COMPACTION PROCESS AND AGGREGATE MOTION CHARACTERISTICS OF ASPHALT MIXTURES UNDER DIFFERENT LOADING METHODS

To investigate the compaction process and aggregate movement characteristics of asphalt mixtures under different loading methods, static compaction and rotary compaction experimental tests are conducted using smart rock. At the same time, 3D laser scanning equipment and image processing technology are used to construct coarse aggregates with real morphological characteristics, and a discrete element model of the compaction process of asphalt mixtures is established, the accuracy of the model is verified with the help of smart rock test results. Finally, the aggregate movement and contact conditions inside the asphalt mixture are analyzed. The results show that: the uniformly growing vertical compaction load could not effectively make the particles move along the horizontal direction, and under the continuous vertical load as well as the cyclic kneading effect, the displacement and rotational ability of the particles in the horizontal direction are stimulated, and the densification of the material is finally achieved; the aggregate-aggregate contact force of the test specimen is larger under the uniformly growing vertical compaction load, and the cyclic kneading effect mitigated the resistance to high compaction in the test specimen. The formation of the compaction resistance of the specimen is reduced by the periodic kneading action, which leads to a better compaction effect in the later stage; the particles close to the loaded area are subjected to more intense motion, the active compaction zone is more active than the passive compaction zone, and the coefficient of variation of the particles' motion in the edge area is higher.