Quantitative Evaluation and Influence Mechanism of Interaction between Asphalt and Mineral Fillers

In order to evaluate the interaction ability between asphalt and mineral fillers and explore the influence mechanism of the characteristics of asphalt and mineral fillers on the interaction ability. Limestone (LS), granite (GN), fly ash (FA), and coal gangue (CG) fillers were added to the base asphalt to prepare asphalt mastic. The dynamic shear rheometer (DSR) tests were conducted to obtain the rheological properties of asphalt mastic. Based on the Palierne model, the evaluation index of interaction ability between asphalt and mineral fillers was proposed. The influence mechanism of asphalt and mineral fillers characteristics on the interaction ability was analyzed through microscopic and physical-chemical tests. The results show that the interaction ability between different mineral fillers and asphalt types is CG > LS > FA > GN. There is a good correlation between the external specific surface area of mineral fillers and the evaluation index, which can be considered a factor in the selection of mineral fillers. There is no new substance formed after mixing mineral fillers and asphalt. Physical and chemical adsorption is the major interaction between them. Among the four types of mineral fillers, coal gangue fillers have the strongest adsorption on asphalt, so coal gangue fillers have a strong interaction ability with asphalt.