Nano-Interaction Mechanism Between Crumb Rubber and Asphalt Components: A Molecular Dynamic Study

Asphalt modified with treated waste tires has good environmental protection and application value. However, the nano-interaction mechanism of crumb rubber (CR) and asphalt (especially its components) is unclear. In this study, molecular models of asphalt, asphalt components, CR, and CR-modified asphalt (CRMA) were constructed by molecular dynamics (MD) simulation. The validity of the model construction and parameter setting was verified by multiple indexes. The influence mechanism of CRMA density, asphalt-CR compatibility, mechanical indexes, and binding energy under the influence of temperature, CR dosage, and other factors was systematically analyzed. Results showed that the optimum temperature for preparing and storing to prevent segregation did not coincide. The solubility parameters (SP) prediction model of the asphalt’s four components was obtained based on the multiple linear regression method. CR could enhance the mechanical properties of asphalt, but the improvement was limited to small dosages. Increasing the dosage can enhance the mechanical properties of asphalt; the mechanical properties can be significantly improved in medium- and high-temperature conditions. Bulk modulus and shear modulus were recommended for preferential analysis of the mechanical properties of CRMA. It is recommended that the optimal dosage be 20%.