Polyethylene based on molecular weight design for eco‐friendly asphalt

Abstract Polyethylene (PE) is widely used as a modifier for asphalt due to its low cost. However, PE increases the high‐temperature viscosity of asphalt, leading to higher construction temperatures and harmful emissions. In this study, PE‐modified asphalt with good road performance, energy saving and emission reduction was synthesized by adjusting the molecular weight ( M w ) of PE. By studying the effect of PE with different M w on the viscosity of asphalt, the M w of PE that can reduce the high‐temperature viscosity of asphalt was concluded and the target product PE‐4 was synthesized. PE reduces the high‐temperature viscosity of asphalt when its M w is less than the critical molecular weight ( M c ) for molecular chain entanglement in the molten state. PE‐4 successfully reduced the high‐temperature viscosity of matrix asphalt. The pavement performance of PE‐4 modified asphalt was characterized. The results showed that PE‐4 reduced the penetration of asphalt, and improved its softening point, ductility, and rutting resistance. PE‐4 modified asphalt is an eco‐friendly asphalt with good road performance. The above data proved that PE with M w less than M c makes PE a promising asphalt modifier, which is beneficial to the green utilization of PE.