Investigation of Surface Texture and Degradation Characteristics of Asphalt Mixtures with Various Lithology Combinations of Aggregates

ABSTRACT Owing to the limited aggregate resources and economic concerns, more and more asphalt pavement surfaces have to use coarse aggregates with a lithology combination. However, the texture deterioration characteristics are still unknown for asphalt pavement surface with a lithology combination of coarse aggregates under traffic loadings. This study aims to investigate the texture depth deterioration of asphalt mixture prepared with varying lithological coarse aggregates by laboratory polishing tests combined with raster scanning tests. The morphological characteristics and chemical compositions of three lithology types of coarse aggregates (i.e., limestone, basalt, and diabase) were quantified by the Aggregate Image Measurement System II and X-ray fluorescence, respectively. Three-dimensional (3D) surface texture of three types of asphalt mixture (asphalt concrete–13, stone mastic asphalt [SMA]-13, and open graded friction course–13) were reconstructed using raster scanning method and validated by computed tomography scanning method. Different combinations of mineral aggregates (e.g., lithology type and particle size) were used to prepare SMA-13 slabs. Laboratory accelerated polishing tests were conducted on the compacted slabs. The cross-sectional profiles of slabs after different polishing times were compared and mean profile depth was calculated. Results show that the raster scanning is a low-cost effective method for reconstructing 3D surface texture and cross-sectional profile of asphalt mixture. As the polishing times increase, the altitude of the peak positions in the cross-sectional profile shows a rapid and then slow decrease. Using varying lithology aggregates could not only alter the initial texture depth of asphalt mixtures but also have an obvious effect on texture deterioration under repeated loading. For asphalt mixture with the nominal maximum aggregate size of 13.2 mm, coarse aggregates consisting of 4.75–9.5-mm basalt, 9.5–13.2-mm diabase, and 13.2–16-mm basalt have a superior abrasion resistance.