Hawaii faces a growing plastic waste problem. Recycling is expensive and difficult on the islands, and discarded fishing nets (the largest source of Hawaii’s marine debris) continue to wash ashore and drift in surrounding waters. Researchers are now exploring an innovative way to tackle both challenges at the same time by turning discarded plastics into roads.
At the spring meeting of the American Chemical Society, researchers from Hawaii Pacific University presented early results from a project examining whether locally recovered plastic waste could be incorporated into asphalt pavement.
Since 2020, most new roads in Hawaii have been built with a more durable type of asphalt that contains polymer additives. Scientists wondered whether some of those materials could be replaced with recycled plastics collected locally, including household plastics and abandoned fishing nets recovered from the ocean.
Working with the Hawaii Department of Transportation, researchers paved test sections of a residential street on Oahu using conventional polymer-modified asphalt, asphalt containing recycled household plastic, and asphalt made with recycled fishing nets. The research team then monitored the pavement and analyzed road dust and stormwater to determine whether the recycled materials released more microplastics than conventional asphalt.
The early results were encouraging. Roads made with recycled plastics did not shed more polymer material than standard asphalt.
More testing is needed to see how these roads perform over many years of use. But if the results continue to hold up, recycled plastics could become part of the infrastructure communities rely on every day.
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Paving Hawaiian roads with recycled plastics and abandoned fishing nets
