Key parameters and effects in image processing and aggregate–aggregate contact calculation of asphalt mixtures

Abstract

At present, there is no standard way of acquiring images, addressing errors in various image processing steps, and analyzing skeleton contact parameters. To promote the application of image processing technique in the design, construction monitoring, and quality inspection of asphalt mixtures, this study investigates the key factors affecting the two-dimensional image processing accuracy of asphalt mixtures, and the impact of parameters on the contact structure of asphalt mixture skeleton during the contact analysis is studied. Finally, data accuracy requirements for image processing and contact analysis are proposed. The results indicate that the camera lens should be parallel to the slice with a tilt angle of less than 15°, the error of the passing rate of each sieve remains within 5.0 %. The smaller the aggregate particle size, the greater the impact of aggregate edge recognition error on the aggregate particle size, aggregates with a particle size greater than 2.36 mm are less affected by edge recognition error. For aggregate–aggregate contact analysis, it is appropriate to set the contact threshold to 0.23 times the minimum calculated particle size. To ensure the accuracy of image processing and contact analysis, at least 10 cross-sectional images should be prepared, and the average value can be taken as the representative value of the indices. The conclusions can improve the accuracy and reliability of image processing, providing more accurate guidance for the design and construction of asphalt mixture.