Microstructural and micromechanical properties of field and lab-compacted asphalt mixtures

There are two main objectives for this paper. The first is to study the microstructural properties such as air void distribution under laboratory and field compaction patterns of asphalt mixtures. The second is to investigate the air void effect of the mechanical properties of the asphalt mixtures under the field and laboratory compaction using distinct element models (DEM). The laboratory and field compacted specimens were simulated using two-dimensional (2D) and three-dimensional (3D) DEM. The laboratory specimens and field core asphalt mixture samples were scanned with X-ray computed tomography techniques to obtain the images of the asphalt mixture microstructure with the air void distributions. Then, these specimens and samples were used to investigate the air void effect of the mechanical properties. The samples were from both laboratory and field compaction. Laboratory compaction was conducted using a Superpave gyratory compactor. Field cores were obtained from the asphalt pavements. 2D and 3D distinct element models were prepared in order to evaluate the stiffness properties of the mixtures. In the 2D models, both vertical and horizontal-cut images of the 3D specimens were used. In addition, the relationship between the mixture modulus and the air void levels was investigated.