In a sustainable twist to the saying “When life gives you lemons, make lemonade,” researchers in Hawaii are developing a method to convert discarded fishing nets and plastic trash into asphalt roads.
Their early tests show that incorporating recycled plastic into asphalt is technically viable and bears minimal risk of shedding microplastics that could end up in the oceans. The team from the Center for Marine Debris Research at Hawaiʻi Pacific University presented their innovative solution to the island’s plastic waste problem at the American Chemical Society Spring 2026 conference.
“By reusing plastic waste that is already in Hawaii, we can reduce the environmental and economic impacts of transporting waste plastics from the islands, incinerating it or dumping it in Hawaii’s overflowing landfills,” said lead researcher Jeremy Axworthy in a press release.
The idea of using plastic waste in paving has been around for a while. Called polymer modified asphalt (PMA), the product is made by adding styrene rubber particles to the asphalt paving mix. This keeps plastic waste out of the environment and landfills, and it can purportedly help reduce greenhouse gas emissions, energy consumption, and road resurfacing needs, according to the chemical company Dow.
Compared to conventional paving materials, PMA is also more elastic, enabling the pavement to better hold up to cracking, rutting, and water damage. This is especially helpful in tropical regions like Hawaii, where traditional asphalt takes a beating from high temperatures and moisture levels. In fact, Hawaii’s roads have been mostly paved with polymer-modified asphalt since 2020.
But the Hawaii Department of Transportation (HDOT) wanted to see if it whether asphalt made with post-consumer would work as well as PMA. So they approached Axworthy, Jennifer Lynch, and their colleagues. The researchers collected abandoned fishing nets, as well as plastic debris from beaches, picking out waste made with a durable plastic called polyethylene found in milk jugs.
A local Oahu paving company mixed the shredded and ground plastic waste into their asphalt mix. Then it paved roads with this material as well as standard PMA.
After almost a year of regular wear and tear from driving, Lynch’s team set out to measure the microplastics shed from the two pavements. They collected road dust samples from each type of pavement and tested the samples for microplastic shedding.
The researchers conducted mechanical tests with pavement samples and analyzed simulated stormwater collected from the experimental road sections. They found that pavement made with recycled polyethylene did not release more polymers than the control PMA pavement.
Their data showed that polymers shed by tires far surpassed the polymers shed from the pavement. “We saw tire wear swamps the signal of polyethylene by orders of magnitude,” said Lynch in a press release. “Some people think plastic recycling is a hoax, that it doesn’t work; it’s too challenging. But this work demonstrates that recycling can work when society prioritizes sustainability.”
Image: ©Anthropocene Magazine (made with Photoshop)
