The Effect of Waste Engine Oil and Waste Polyethylene on UV Aging Resistance of Asphalt.

Waste engine oil (WEO) and waste polyethylene (WPE) are two common wastes, which are easy to pollute the environment. As the primary material in road construction, natural asphalt is a non-renewable energy source and asphalt is vulnerable to ultraviolet (UV) radiation during the service life. It results in degradation of asphalt pavement performance. In this paper, 22 wt % to 82 wt % of WEO and WPE were used to modify asphalts and the UV aging simulation experiment was carried out. The physical parameters of asphalts before the UV aging experiment show that the asphalt containing 42 wt % WPE and 62 wt % WEO mixture (42 wt % WPE + 62 wt % WEO) has similar physical properties with that of the matrix asphalt. Besides, gel permeation chromatography (GPC) verifies that the molecular weight distribution of the asphalt containing 42 wt % WPE + 62 wt % WEO is close to that of the matrix asphalt. The storage stability test shows that 42 wt % WPE + 62 wt % WEO has good compatibility with the matrix asphalt. The functional groups and micro-morphology of asphalts before and after the UV aging experiment were investigated by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). FTIR results display that 42 wt % WPE + 62 wt % WEO can effectively reduce the formation of carbonyl and sulfoxide functional groups. AFM shows that 42 wt % WPE + 62 wt % WEO can also retard the formation of a "bee-like" structure in asphalt after the UV aging experiment. Based on the above results, it can be concluded that WEO and WPE mixture can replace part of asphalt and improve the UV aging resistance of asphalt.