Characteristics of asphalt binder modified with waste vegetable oil and waste plastics

Abstract

Asphalt binder, which is a by-product of petroleum distillation, is vastly consumed in pavement construction. However, petroleum is highly rare as a nonrenewable source resulting in the short-term supply of petroleum asphalt. The improper elimination of waste oils and plastics presents numerous environmental problems. This paper investigates the possibility of using waste vegetable oil (WVO) in combination with waste plastics; Low density polyethylene (LDPE) and Polyvinyl chloride (PVC), as enhancing additives for (40/50) asphalt cement in order to mitigate the illegal disposal of these wastes and modify asphalt binder properties as well as reduce the consumption of bitumen thereby reducing the cost. Three percentages (1%, 2% and 3%) of waste vegetable oil were firstly added to the control asphalt to prepare WVO-modified bitumen. Three percentages (1%, 3% and 5%) of LDPE and PVC were then added separately to WVO-modified binder. Physical properties of the original and modified asphalts were studied using several laboratory tests. The results indicated that bitumen modified with waste vegetable oil has better thermal cracking resistance and lower rutting resistance and it is more suitable to be used in moderate and cold regions, while the addition of plastic wastes in combination with waste vegetable oil could reverse these effects. As a final result, utilizing suitable amounts of waste vegetable oils and waste plastics as asphalt cement additives can give new binders that are suitable for both hot and cold regions. Finally, it can be concluded that the recycling of waste oils and plastics in hot mix asphalt industry is workable and can be seen as a convenient and valid method for eliminating these wastes.