Abstract:To address the insufficient storage stability caused by poor compatibility in polyethylene-modified asphalt, a pre-melting physical treatment process is proposed. No.70 base asphalt is modified by using recycled low-density polyethylene (RPE). Through softening point difference tests, dynamic shear rheology (DSR), bending beam rheology (BBR) and fluorescence microscopy (FM) tests, the performance characteristics of modified asphalt under different preparation methods are systematically evaluated. The results demonstrate that the pre-melting process effectively improves the dispersion state of RPE in asphalt, significantly alleviating polyethylene floatation and phase separation during high-temperature storage while enhancing storage stability. Rheological tests reveal that while the high-temperature rutting resistance of pre-melted RPE-modified asphalt under high dosage slightly underperforms compared to direct particle addition, it demonstrates superior creep stress dispersion at low temperatures, effectively delaying low-temperature damage. FM analysis and binarization analysis indicate that pre-melting reduces RPE aggregate particle size below 10 μm. And a rich network structure is formed in the asphalt and the uniformity of distribution between the upper and lower layers is improved after segregation. This study result confirms that the pre-melting method can enhance RPE-modified asphalt performance without additional materials, providing a reference solution for high-value utilization of waste plastics and industrial production of high-performance asphalt.
