The Influence of Mesoscopic Characteristics of Mineral Powders Fillers on the Rutting Factor (G*/sinδ) of Asphalt Mortar

This study aims to investigate the effect of the mesoscopic characteristics of mineral powder fillers on the rutting resistance of asphalt mortar. Extraction and sieving tests were used to obtain the buton rock asphalt (BRA) ash with particle size smaller than 0.075 mm, which is consistent with that of the conventional mineral powder. The mesoscopic characteristics of BRA ash and conventional mineral powder were measured by SEM image analysis and the osmotic free pressure water method. Mesoscopic structure models of structural and free asphalts in mortar were obtained. The 70# matrix asphalt was used to prepare two kinds of asphalt mortar with BRA ash and conventional mineral powders fillers. The rutting factor of the two asphalt mortars was tested by dynamic shear test (DSR). Test results show that the ash extracted from BRA has a similar mesoscopic classification with the conventional mineral powder. Still, its fractal dimensions are larger, indicating the particles in BRA ash have more complex shapes and rougher surfaces, which is beneficial for forming structural asphalt and subsequently increasing the rutting factor (G*/sin delta), i e, improving the rutting resistance of the asphalt mortar.