A new sustainable road paving initiative that will keep nearly 200,000 plastic bottles out of the landfill is becoming a reality thanks to a new partnership involving the University of Hawaiʻi at Mānoa.
The Hawaiʻi Department of Transportation (HDOT) is leading the project to combine recycled plastics with an asphalt mix to form a sustainable road paving material. Over the next 18 months, UH Mānoa’s College of Engineering is one of the institutions that will evaluate the performance of the plastic modified asphalt and the potential of the material to release microplastics into its surroundings.
“We are always looking at ways to improve our roads,” said Professor Adrian Ricardo Archilla from UH Mānoa’s Department of Civil and Environmental Engineering. “In this case, we will try to use recycled materials and at the same time see if we can either improve or at least not lower the performance compared with the existing mix that is being used.”
HDOT is testing the material as part of its sustainable transportation initiatives through a pilot project on Fort Weaver Road near Puʻuloa Beach Park in ʻEwa Beach. The paving began on October 11 and the project is expected to be complete in late July 2023. The amount of plastic modified asphalt used in this pilot—1,950 tons—will keep the equivalent of 195,000 plastic bottles out of the landfill.
“Using plastic in our asphalt has the potential to make our roads stronger and upcycle material that would be otherwise headed for a landfill,” said HDOT Deputy Director for Highways Ed Sniffen. “Even though we’re using a material that has been used on roads in the United States for over five years, we need to make sure the mix is right for Hawaiʻi and our environment.”
A section of control pavement using polymer-modified asphalt will be installed next to the plastic road. The project will also evaluate various high recycled asphalt (RAP) mixes using 50% RAP. Testing of the high RAP mixes will provide experts with the data necessary to more than double the percentage of recycled asphalt used on Hawaiʻi roads.