Evaluating the Homogeneity of the Interval Quality of Asphalt Pavement Structure with X-Ray Computed Tomography

Abstract

The method that uses only a compaction degree indicator in the core specimens of asphalt pavement for evaluating construction quality cannot effectively reflect the volumetric property and inner structure of asphalt mixtures. Virtually reconstructed specimens are generated by cone-beam scanning field cores with a high-accuracy industrial X-ray computed tomography, and the vertical slice images and digital processing of the aggregate are adopted. To evaluate the vertical structural segregation of the field core specimens, indicators such as the non-uniformity coefficient of coarse aggregate and the vertical variation coefficient of specimens are presented. Results indicate that (1) in various construction control situations, the inner structures of asphalt pavement with the same graded mixture have obvious differences; (2) coarse aggregate particles in the specimens show the regularity of homogeneity in the middle and segregation at both bottoms; and (3) pavement specimens have a gentle homogeneity curve and a small vertical variation coefficient in a road section with superior construction control.