Comparative analysis of HMA aggregate variability based on impacting and gyratory compaction

Abstract

In proportion design of hot mix asphalt (HMA), the aggregate gradation in HMA is one of the most important influencing factors on HMA mechanical behavior. During the process of aggregate compaction, the gradation of the aggregate will change at some extent, namely, the aggregate gradation after compaction will be different from the original design gradation, it will influence the HMA design results. Therefore, study on the variability of aggregate gradation at different compaction conditions has a theoretical and practical value. The objective of the project is to explore the influence of different compacting methods on aggregate gradation between Marshall and Superpave methods. Different compaction methods are used to compact different aggregates, then the variability of aggregate gradation under different compaction conditions is analyzed. The research results have shown that although the method of Superpave gyratory compaction generally has the less influence on aggregate gradation than that of Marshall impacting compaction, the detailed influence on the gradation of coarse, medium and fine aggregates between two methods is different. The findings can provide a technical reference for aggregate gradation in HMA proportion design.