Investigation of the effects of chemical modification and oxidative aging on the properties and compatibility of rubber asphalt based on thermodynamic principles

Abstract

This study is based on the principles of thermodynamics and utilizes the Hansen solubility parameter theory and molecular dynamics simulation techniques. By introducing solubility parameters and interaction parameters, modified molecular models for rubber and aged asphalt are constructed. The study systematically investigates the mechanisms underlying the effects of polyphenolic chemical modification and oxidative aging on the performance and compatibility changes of rubber asphalt. The results show that the solubility parameter (δT) of the asphalt system decreases gradually with increasing temperature. At a temperature of 160 °C, the solubility parameter difference (ΔδT) between the asphalt and rubber power (RP) is minimized, indicating the highest degree of compatibility between the two materials. After chemical modification, the solubility parameter of the RP increases, the difference in solubility parameter between the RP and asphalt decreases, and the chemical modification improves the compatibility of the two phases. Oxidative aging causes a shift in the composition ratio of asphalt towards asphaltene, leading to an increase in the solubility parameter of asphalt and a larger difference in solubility parameter between the system. As a result, the compatibility of modified asphalt decreases.