Spatial evolution characteristics of asphalt surface structure and its influence on surface interaction properties

Abstract

Air-asphalt surface structure (asphalt surface structure) is widely found in asphalt mixture and is the main structure that directly interacts with air, precipitation and sunlight. To explore the physicochemical properties of asphalt surface structure, the spatial evolution characteristics and interaction properties were studied by combining theory, test and simulation. Firstly, the gestation, generation and development of asphalt surface structure were explained theoretically, and the categories of asphalt surface structure were proposed. Secondly, the spatial evolution characteristics of asphalt surface structure were analyzed by the combination of macro and micro tests. Finally, the relationship between asphalt surface structure and air (N2, O2) and precipitation (H2O) was discussed by using molecular dynamics. It was found that, theoretically, asphalt surface structure can be divided into "initial surface structure", "stable surface structure" and "aged surface structure", and the "stable surface structure" is the ideal surface state. The low temperature environment is conducive to the adsorption of air (N2, O2) by the asphalt surface structure, the "initial surface structure" has a relatively high adsorption interaction capacity. Additionally, the interaction between precipitation and asphalt surface structure is gradually enhanced with the increase of temperature, and the interaction between "aged surface structure" and precipitation is relatively stronger. The study further expands the exploration of asphalt surface structure and provides a theoretical explanation for asphalt aging behavior.