Validity Evaluation of Different Laboratory Asphalt Concrete Material Compaction Methods with Digital Image Processing Technique

The digital image processing technique was applied to analyze and evaluate the coarse aggregate orientation property in asphalt mixture specimens. Specimens produced by Marshall compaction, vibratory compaction, gyratory compaction, and roller compaction were separately evaluated and compared with the core samples drilled from real asphalt pavement. The quantitative index named maximum likelihood angle (MLA) was developed for statistical analysis on the coarse aggregate orientation. It is found that the coarse aggregate orientation properties of the specimens using different compaction methods have great differences, the specimens produced by laboratory Marshall compaction method has no statistical discipline, the specimen produced by laboratory roller compaction method has the best similarity property with the real asphalt pavement. The results indicate that the MLA is an effective index in evaluating the aggregate orientation, and the roller compaction method should be the first choice in laboratory asphalt mixes specimen preparation.