Morphological characteristics of mineral filler and their influence on active adhesion between aggregates and bitumen

Abstract

Mineral filler has a significant effect on the service performance of asphalt pavement. This study used morphological analysis and active adhesion test to explore the relationship between morphologies of filler and pavement properties. Limestone fillers with different morphologies were prepared by four crush methods for adhesion analysis of aggregates-bitumen interface. The coating ratios were calculated by image analysis and volumetric analysis, used to represent the active adhesion properties. The results show that the roundness of jaw-crushed filler is the smallest, and it can be attributed to the heavier force of jaw crusher than the other three methods. There is no evidence that the crush methods contribute directly to the angularity of filler. Furthermore, a close negative linear relationship was found between the roundness of fillers and adhesion properties. The recommended angularity and roundness of mineral filler should be less than 0.895 and less than 0.515, respectively, to ensure a well-accepted active adhesion between aggregates and bitumen materials.