Researchers in Hawaii are incorporating discarded fishing nets and household plastics into asphalt for roads. Early tests indicate these mixtures release no more microplastics than standard pavement. The work was presented at the American Chemical Society spring meeting.
Hawaii faces challenges with plastic waste due to high recycling costs and marine debris washing ashore. Researchers at the Center for Marine Debris Research partnered with the Hawaii Department of Transportation to test recycled materials in polymer-modified asphalt.
Jeremy Axworthy presented findings showing that pavement made with recycled polyethylene from fishing nets and local waste performed similarly to conventional styrene-butadiene-styrene asphalt. Field trials on an Oahu residential street used three mixtures, with road dust collected after 11 months for analysis.
Laboratory and field tests using pyrolysis gas chromatography-mass spectrometry found tire wear particles far exceeded any polyethylene signals from the recycled plastic. The team noted that plastics blend into the asphalt binder, limiting separate microplastic release.
More long-term durability testing is required before wider adoption. The project aims to reduce landfill use and marine debris while supporting local infrastructure needs.