Effect of Waste Vegetable Oil on Properties of Asphalt Cement and Asphalt Concrete Mixtures: An Overview.

With the rapid evolution of the pavement industry and growing traffic on roadways, construction materials have also evolved, with non-traditional materials increasingly being employed. The key motivation for using non-conventional components was the scarcity of natural resources and their high costs, which drove the trend toward using waste materials in asphalt pavement construction to achieve environmental sustainability. This paper aims to provide an overview of the effect of adding waste vegetable oil (WVO) to asphalt binders and asphalt concrete mixtures. The information was obtained from several Scopus database studies conducted over the period of 2005 to 2022 and was used to evaluate the performance of asphalt under different dosages of WVO. It was concluded that almost all the researchers reached an agreement that adding WVO to the asphalt reduces the softening point, viscosity, complex modulus, creep stiffness, the resistance to deformation, and elastic recovery quality of asphalt. On the other hand, it increases its penetration, ductility, phase angle, m value, stress relaxation characteristic, and thermal cracking resistance. For asphalt mixtures, it was found that adding WVO increases the flow value and Voids in Mineral Aggregate (VMA). In contrast, it reduces stability and the air voids in the mixture. [ABSTRACT FROM AUTHOR]