A Graphene-Enhanced Recycled-Plastic Asphalt Mixture Modifier: Two Case Studies in the United Kingdom and the United States of America

In addition to heavy and frequent traffic loads, climatic conditions pose significant challenges for asphalt pavement designers. The situation becomes even more challenging in areas with high average temperatures and extreme climates, greatly affecting design parameters. This paper introduces an innovative asphalt mixture modifier made from carefully selected recycled plastics and graphene nanomaterial, which has been trialled in both the United Kingdom and the United States of America. This modifier, applied through a dry method/process, enables the production of a high-performance asphalt mixture, especially suitable for areas with heavy traffic loads or those located in hot climate regions. From the environmental perspective, the resultant product exhibits a remarkably low embodied carbon, as demonstrated in the corresponding Environmental Product Declaration (EPD), making it a sustainable alternative to other common asphalt modifiers. The test results presented in this paper reveal that asphalt mixtures with this modifier exhibit a higher modulus, increased strength, superior resistance to permanent deformation, comparable or better fatigue performance, and improved low-temperature performance when compared to their counterpart reference asphalt mixtures. In addition to its environmental benefits, this asphalt modifier has been rigorously examined and monitored in numerous projects over the past few years. It has been successfully employed in many large-scale projects both in Europe and the United States of America. Most recently, the Virginia Department of Transportation placed a field trial featuring the use of this asphalt modifier as part of their ongoing effort to evaluate “Sustainable Surface Mixtures Incorporating Recycled Plastic Waste.”