Influence of rubber cross-linking degree on compatibility and performance of modified asphalt: Rheological characterization and molecular simulation

Incorporating waste tire rubber into asphalt pavement offers an environmentally friendly solution for recycling end-of-life tires while enhancing the performance and durability of road materials. However, the compatibility between rubber and asphalt limits their high application in asphalt pavement. This study aimed to investigate the effect of crosslinking degree difference on the compatibility and performance of recycled rubber modified asphalt. The recycled rubber with different crosslinking degree was prepared by twin-screw extrusion. DSC and TGA tests were adopted to characterize the thermal properties of rubber-plastic pellets. Rheological and microscopic tests were conducted to evaluate the storage stability, rutting, fatigue, and low-temperature cracking resistance of modified asphalt under different crosslinking degree and dosage of rubber particles. Results showed that the decrosslinking of waste tire rubber facilitate the dispersion of rubber particles in asphalt and improve the storage stability of modified asphalt with high rubber content. Recycled rubber with low crosslinking degree can improve the fatigue and low temperature performance of modified asphalt. The molecular dynamics simulation further demonstrates the enhanced compatibility of asphalt and low crosslinking rubber particles with the low value of electric dipole moment difference, solubility difference and the improved interaction energy. This study provides theoretical support and technical guidance for the large amount utilization of waste rubber in asphalt pavement. • Recycled rubber with different degrees of degradation was prepared based on a twin-screw extruder. • The storage stability of reclaimed rubber modified asphalt with different degradation degree was evaluated. • The effects of recycled rubber with different degradation degrees on the rheological properties at high and low temperatures were analyzed. • The interaction mechanism between recycled rubber and asphalt with different degradation degrees was studied by molecular simulation.