The research on the meso-structure distribution mechanization and pavement performances of Superpave mixtures at different SGC gyrations.

The Superpave 5 presents that compacting work should be integrated into the design of asphalt mixtures. Reducing gyrations for Superpave Gyratory Compacting increases the anti-cracking performance but decreases the anti-rutting performance. To further explore the performance change with decreasing gyrations, the meso-structure properties of Superpave mixtures and the correlation between the meso-structure properties and asphalt mixture performances were analyzed. The aggregate phase, pore phase, and mortar phase were separated first through the CT images. Subsequently, the distribution properties of the aggregate equivalent diameter and inclination were investigated. Besides, the pore phase and mortar phase were converted into PNM(pore network model). The distribution properties and volume properties of the PNMs were explored. Moreover, performance tests were conducted. Finally, the grey relation analysis between the meso-structure indices of the multiphases and the asphalt mixture performances was determined. The results illustrated that increasing gyrations increased the total aggregate equivalent diameter and dispersed the aggregate equivalent diameter distribution. And increasing gyrations made the spatial structure more concentrated. In addition, increasing gyrations made the aggregates rotate along the z-axis in the vertical direction and closer. All the distributions of the azimuth angle became more dispersed. The PNM simulation results implied that the mixture under 50 gyrations had better connectivity of connected pores verified by laboratory permeability test. For the mortar phase, increasing gyrations increased the summation of coordination number, the volume of connected pores, and the volume of channels, which also improved the connectivity. Finally, the high-temperature, low-temperature, and fatigue performances were mostly influenced by the mortar phase through grey relation analysis, and they were improved with increasing connectivity of the mortar phase. The middle-temperature flexibility index decreased with increasing aggregate volume and synthetic centroid distance. However, the middle-temperature fracture work increased with increasing μ and a more dispersed distribution of the polar angle. The results contribute to integrating compacting work into asphalt mixture design. • Multiphases are separated and meso-structure indexes are proposed. • Grey relation analysis is conducted between meso-structure indexes and pavement performances. • Increasing gyrations has a significant impact on the spatial distribution and inclination properties of aggregate phase. • Increasing gyrations improves the connectivity of mortar phase while reducing the connectivity of pore phase. • The properties of aggregate phase and the connectivity of mortar phase make a significant effect on pavement performance. [ABSTRACT FROM AUTHOR]