In late 2016, media reports began generating an interest in the possibility of using recycled plastic waste in asphalt mixtures. The idea was marketed as an opportunity to simultaneously improve the quality of asphalt pavements and help address the issue of waste plastic in cities, towns, and waterways across the United States. The current waste plastic challenge is a critical concern; there is equal concern about the current state of the aging transportation infrastructure in the United States. Investment in our transportation system must focus on delivering long-lasting, high performing pavements as cost-effectively as possible. While magazine articles and videos have claimed positive impacts of using recycled plastic modified (RPM) asphalt, such as increased service life and reduced need for polymers to modify asphalt binders, and while preliminary research suggests some of these benefits may be realized, a full program of research to confidently back these claims is lacking.
There is a mounting body of literature on the use of recycled plastic waste in asphalt, but much of this work lacks a clear experimental plan and suffers from the use of dated test methods. This project will assess the feasibility of using RPM asphalt mixtures as a sustainable solution for both improving the performance of asphalt pavements and reducing the amount of plastic waste in the United States. FHWA is funding research to evaluate the compatibility and stability of post-consumer recycled (PCR) plastics with asphalt binder prepared by the wet process. The project will work concurrently with the FHWA project to evaluate RPM asphalt mixtures produced by the plant-mixed or dry process.
The objective of this research is to evaluate the impact of post-consumer recycled plastic waste, including, but not limited to, low density polyethylene (LDPE), high density polyethylene (HDPE), and polypropylene (PP), on the performance properties of asphalt mixtures when added using a plant-mixed or dry process.
STATUS: The Phase I interim report and proposed Phase II work plan are available at https://onlinepubs.trb.org/Onlinepubs/nchrp/docs/NCHRP9-66InterimReportwithAppendixFINAL.pdf.