Role of Pyrolysis Wax on Enhancing the Performance of Waste Plastic Modified Asphalt Prepared with the Wet Modification Process

Abstract

Using waste plastics in pavement construction has been attracting significant attention because of its ability to increase the sustainability of the road infrastructure, economic benefits, and superior performance with regard to resistance against rutting. However, poor compatibility, mainly because of differences between the properties of plastics and asphalt with regard to density, molecular weight, polarity, and solubility, has been one of the major drawbacks that has been limiting their successful application. As a result, this study aims to use a wax-based product, which is a by-product of the pyrolysis of waste polyethylene, to enhance the compatibility between asphalt and two main types of polyolefins: polyethylene and polypropylene. The main objective was to use pyrolysis wax to enhance the compatibility between asphalt and plastics, as well as eliminating two of the primary downsides of plastic-modified asphalt: poor resistance to cold weather and fatigue-related cracks. To achieve this, after the incorporation of pyrolysis wax to plastic-modified asphalt during the wet modification process, the rheological performance of the asphalt containing plastics was evaluated by conducting different laboratory testing. The results indicate that a proper ratio between pyrolysis wax additive and plastic asphalt binder containing 2% polyolefins and 1.5% pyrolysis wax overall can demonstrate a superior performance with regard to the different aspects of performance, including resistance against rutting, thermal cracking, and fatigue, without sacrificing any other aspects of the performance when compared with base PG 58-28 binder and plastic-modified binder.