Effect of epoxy resin content and conversion rate on the compatibility and component distribution of epoxy asphalt: A MD simulation study

Molecular dynamics simulation technology was introduced into the characterization of epoxy asphalt performance, to display the reaction process between the epoxy resin and curing agent in epoxy asphalt clearly and explore the influence of epoxy resin content and conversion rate on the epoxy asphalt performance containing thermodynamic, compatibility, component distribution and diffusion. The reaction between the epoxy resin and curing agent was realized through Perl script, and epoxy asphalt molecular dynamics models with different resin content (25%, 45%, and 65%), and various conversion rates were prepared. Results demonstrated that the addition of epoxy resin enhanced the low-temperature performance of epoxy asphalt, but the increase in conversion rate played a negative impact on low-temperature performance. The CED and solubility parameter were synergistically affected by the epoxy resin content and conversion rate. Furthermore, the raise in the content of epoxy resin was the main reason for enhancing the compatibility between epoxy resin and asphalt. Therefore, the reasonable control of the resin content and conversion rate was beneficial to enhance the stability of the epoxy asphalt system and improve the compatibility between the resin phase and the asphalt phase. 25%-EA and 45%-EA were considered as asphalt phase materials. Aggregation behaviors exhibited between asphaltenes, and adsorption behaviors presented between epoxy resin and asphaltene. With the increase of conversion rate, the adsorption behavior gradually disappeared. 65%-EA belonged to the resin phase material, and the aggregation between asphaltenes was diminished. In addition, the epoxy resin without conversion reaction had the smooth diffusion behavior in epoxy asphalt.