Reactive molecular dynamic investigation of the oxidative aging impact on asphalt

The oxidative aging of asphalt will cause the evolution of internal components and make the physical properties reduce. It has been proved that ketones and sulfoxides are the main products of asphalt oxidation. In this study, reactive molecular dynamic method is adopted to investigate the oxidative aging behavior of asphalt in picosecond scale. The variation regularity of ketones, sulfoxides and the intermediate products with the oxidation process are analyzed quantitatively. The formation of sulfoxides groups preceded that of ketones, and the intermediate products (hydroperoxide and hydrogen hydrogen free radical) promote the oxidation reaction. In addition, ketones are more easily formed on cyclic benzyl carbons than branched benzyl carbons. The production of two types of free radicals is the main reason for the polymerization of asphalt. Through studying oxidative aging behavior of asphalt, we hope that this paper can provide novel approach to insight the aging phenomenon of organic materials.