In this work, waste polyethylene (PE)-modified 90# asphalt was made in order to investigate the performance of waste polyethylene-modified high-grade asphalt and the optimal blending quantity. Dynamic Shear Rheology (DSR) and Bending Beam Rheometer (BBR) tests were used to evaluate the high- and low-temperature performance of modified 90# PE-modified asphalt. Infrared spectroscopy and fluorescence microscopy were used to investigate the modification process and distribution status of waste PE in 90# asphalt. The DSR and BBR tests revealed that waste PE enhanced the high-temperature performance of 90# base asphalt and that 5% was the best blending rate. However, the change affects asphalt's low-temperature performance, and the negative effect on asphalt's low-temperature performance was minimized at 1% dosing. The incorporation of waste PE absorbed the light components of asphalt, while waste PE can form a reticulated structure in asphalt, which improves its high-temperature performance but degrades its low-temperature performance, according to the results of infrared spectroscopy and fluorescence microscopy.
Keywords: modification mechanism; modified asphalt; rheological properties; thermal properties; waste PE.