Effects of Gamma-Irradiated Recycled Low-Density Polyethylene on the Creep and Recovery Properties of Asphalt

To improve the performance of recycled low-density polyethylene (LDPE_R), this paper describes the polymer modification of bitumen with gamma-irradiated recycled low-density polyethylene (γ-LDPE_R). The effects of the γ-LDPE_R on bitumen were investigated by means of morphological and chemical analyses, including Fourier-transform infrared spectroscopy and multiple stress creep recovery (MSCR) test. The results showed that the surface of the LDPE_R treated by gamma beam irradiation led to the formation of free radicals and some functional groups that may contribute to the creation of strong chemical bonds between the polymer modifier and bitumen, thus improving the compatibility of the modified asphalt. With the increased use of γ-LDPE_R, the modified asphalt rutting resistance also increased. However, due to the high γ-LDPE_R content of the modified asphalt, undertaking the high-temperature performance evaluation of the applicability of MSCR deserves further study.