Application of X-ray computed tomography imaging in the digital modeling of asphalt mixtures: A state of the art review

To enhance the application value of CT technology in road engineering and offer significant technical support for digital characterization and visual examination of the microstructure of asphalt mixtures, the operational principles of X-ray CT and its applications related to the development of digital models for asphalt mixtures were introduced. The factors influencing the quality of CT images of asphalt mixtures have been systematically summarized, and the impact of various scanning process parameters on image quality was analyzed. The characteristics and application scope of CT image quality enhancement and threshold segmentation techniques were elucidated. The primary applications of X-ray CT in the context of digital models of asphalt mixtures were discussed, including phase analysis (encompassing air voids, aggregates, and additives), damage assessment (addressing freeze-thaw damage, mechanical damage, and crack healing), dimensional measurement (such as asphalt mortar thickness and pavement surface texture depth), and virtual experimentation (including finite element and discrete element methods). Additionally, the current state of research and the challenges associated with the use of X-ray CT in the analysis of the microstructure of asphalt mixtures were examined. This study serves as a valuable reference for future investigations into the application of X-ray CT in the digital characterization and analysis of asphalt mixtures. • The characteristics and applicability of quality enhancement methods and threshold segmentation methods for CT images were revealed. • The main applications of X-ray CT in asphalt mixtures digital models were introduced. • The research status and challenges of X-ray CT in the analysis of asphalt mixture microstructure were discussed.