Atlanta, Mar 23: Researchers from Hawaiʻi Pacific University are pioneering an innovative approach to tackle plastic waste by converting discarded fishing nets and residential plastics into asphalt for road construction in Hawaii. The findings were presented at the ACS Spring 2026, hosted by the American Chemical Society.
Hawaii faces significant environmental and logistical challenges in managing plastic waste, particularly marine debris that accumulates in its surrounding waters. This new initiative explores the potential of repurposing such waste into polymer-modified asphalt (PMA), offering a sustainable and locally viable solution.
“This work investigates whether it’s responsible to use recycled plastics in Hawaii’s roads,” said Jeremy Axworthy, a researcher at the Center for Marine Debris Research (CMDR). “By reusing plastic waste already in Hawaii, we can reduce the environmental and economic impacts associated with transporting or disposing of it.”
The research builds on Hawaii’s use of PMA since 2020, a material known for enhanced durability, flexibility, and resistance to cracking, rutting, and water damage—qualities essential for tropical climates. Traditionally made using styrene-butadiene-styrene (SBS), the team explored substituting this with recycled polyethylene sourced from household waste and derelict fishing gear.
The project was undertaken in collaboration with the Hawaii Department of Transportation (HDOT), which partnered with CMDR to both supply marine debris and assess environmental safety. The debris, including fishing nets, was collected through CMDR’s Bounty Project, which incentivizes fishers to remove waste from the ocean.
Jennifer Lynch, Director of CMDR and lead researcher, emphasized the importance of evaluating environmental impact. “Our goal was to determine whether these recycled materials would release microplastics or harmful chemicals into the environment,” she said.
Experimental asphalt mixtures were tested on residential roads in Oahu, incorporating standard SBS, recycled plastics from Honolulu’s waste streams, and recovered fishing nets. After 11 months of usage, researchers collected and analyzed road dust samples using advanced techniques such as pyrolysis gas chromatography-mass spectrometry (Py-GC-MS).
Initial results showed that roads constructed with recycled plastics did not release more microplastics than conventional PMA roads. While microplastic particles were detected, very few originated from the recycled polyethylene, as the materials are fully integrated into the asphalt binder.
Notably, the study found that tire wear contributes significantly more to polymer presence in road dust than recycled plastic materials, highlighting an often-overlooked source of environmental microplastics.
While further research is needed to assess long-term durability, the findings suggest that incorporating recycled plastics into road infrastructure could help reduce landfill waste and marine pollution in Hawaii.
“Some people think plastic recycling is a hoax—that it doesn’t work,” Lynch added. “But this research shows that recycling can be effective when sustainability is prioritized.”
This groundbreaking initiative underscores the potential of circular economy solutions in infrastructure development, paving the way for environmentally responsible innovation in waste management and road construction.
