Downer has signed a ten-year road maintenance contract from the New Plymouth District Council in New Zealand to build roads using material made from plastic waste.

Known as Plas Mix, the new material is made from shredded plastic container packaging materials used for margarine, yoghurt, cottage cheese, butter, bottles for cleaning products among others.

During recent testing in Plymouth, the company used Plas Mix mixed with asphalt for the surfacing of the road.

The trial consumed 500kg of hard plastic waste in 100m² of road, which is the equivalent of material thrown away by around 1,300 people in one week.

Plas Mix was developed by Downer’s Road Science team in collaboration with waste management and resource recovery company EnviroNZ.

Downer’s Murray Robertson said: “The creation of Plas Mix is a collaboration between two commercial companies actively working together to solve significant local and global waste minimisation issues.

“The team are tasked with developing a meaningful outcome that can successfully repurpose waste plastic while not compromising the integrity of the pavement solutions.”

EnviroNZ commercial manager Glen Jones said: “Main benefits of using recycled plastic in roading is that it prevents waste going to landfill. It also eliminates the need to transport and ship these materials thousands of kilometres overseas for processing, which significantly reduces our carbon footprint.”

Downer said that the secondary benefit of the new asphaltic road surfacing was enhanced by adding the plastic, especially in the areas of waterproofing and rutting.

“Main benefits of using recycled plastic in roading is that it prevents waste going to landfill.”

Robertson further added: “Developing practical and cost-effective solutions to sustainability challenges remains front and centre for our team. Reducing solid waste from entering landfills, while reducing our carbon footprint and providing high-quality cost-effective outcomes is a challenging yet motivating assignment for us.”

Under the recently awarded ten-year road maintenance contract, Downer will be responsible for covering urban and rural roads in the district.

The contract also covers road maintenance, CBD cleaning and water and wastewater reticulation renewals, as well as small to medium bridge maintenance.