With the development of modern technology, three-dimensional imaging technology has been increasingly used in several fields. As a non-homogeneous material, the performance of construction asphalt mixtures is not only affected by the material composition, but also closely related to the internal structure. In this paper, the microstructural properties of construction asphalt mixtures are investigated by three-dimensional imaging technology, with the aim of exploring the relationship between aggregate distribution, void structure and asphaltaggregate interface in asphalt mixtures. The study used 3D imaging technology to scan different types of asphalt mixtures and obtained 3D images with sub-millimeter resolution, and then analyzed their internal structural properties. The experimental results show that the distribution of coarse aggregate in dense asphalt mixtures is more uniform and the void structure is tighter, while the open-graded wearing course has larger voids and a looser structure. Through the experiments under different vacuum levels, it is found that vacuum compaction can significantly reduce the size of the voids, and the larger the vacuum level, the stronger the interfacial bond between asphalt and aggregate. Specifically, the maximum void sizes under working conditions were 15 mm and 25 mm, respectively, and the larger the vacuum degree, the smaller the proportion of large-size voids. The study shows that 3D imaging technology can effectively reveal the microstructure of asphalt mixtures, which provides data support for further optimizing the proportion and performance of asphalt mixtures.
