Microscopic adhesion properties of asphalt–mineral aggregate interface in cold area based on molecular simulation technology

Abstract This study aims to investigate the effect of component proportional feature on the microscopic adhesion of asphalt–mineral aggregate interface in cold areas. Different asphalt and mineral molecular models were presented, and a molecular model of asphalt–mineral aggregate interface was constructed on the basis of molecular simulation technology. The influence mechanism of asphalt component characteristics on the microscopic adhesion of asphalt–mineral aggregate interface was obtained through the calculation and analysis of the microinterfacial energy between the components of asphalt and mineral aggregates. The microscopic interfacial energy of asphalt–mineral aggregate with different component proportions and the diffusion law of asphalt with different component proportions on mineral surface were calculated through molecular dynamics simulation. The effect of asphalt component proportional feature on the microadhesion parameters of the asphalt–mineral aggregate interface in cold areas was determined. Results show that the microadhesion of asphalt–mineral aggregate interface and the diffusion rate of asphalt on mineral surface sharply decrease after short-term aging, and the decay trend reduces after long-term aging. The fine wetting effect of saturate and aromatic fractions on the mineral surface is dominant in the occurrence of microadhesion effect on the asphalt–mineral aggregate interface in cold areas. After aging, the proportion of saturate and aromatic in asphalt cannot sufficiently wet the mineral surface, which leads to the decrease of the microscopic adhesion of asphalt–mineral aggregate interface. The aromatic component has the largest effect on the microadhesion of the asphalt–mineral aggregate interface in cold areas, followed by the saturate component, and asphaltene has the smallest effect by comparing the magnitudes of the gray correlation coefficient.