Plastic roads can solve a pollution problem and improve your commute
The world generates nearly 400 million tonnes of plastic waste per year. Much of it ends up in the oceans, endangering wildlife, sometimes ending up in our food chain, and contributing to messes such as the Great Pacific Garbage Patch. Most plastics are recyclable, so there are plenty of other uses they can be put to. One particularly ingenious use being tested around the world, including in Australia and New Zealand, is road construction. Roads made from recycled plastic and other materials are durable, flexible, and lightweight, and soon we may all be driving on them.
Paving a New Way
The surfacing for the $16 million project, begun in Gungahlin in Canberra’s north in March, is made up of plastic bags, glass bottles, printer toner cartridges, and reclaimed asphalt. Last May, a 300-metre stretch of road in Craigieburn, Victoria, was laid using a mix of the same materials. Plastic bags, glass bottles, and toner cartridges were used to pave a road in Snug, Tasmania, in December. Had they not been turned into roads, these materials would all have headed to landfill. The reclaimed asphalt was taken from existing roads, glass from kerbside collections, and soft plastic from container deposit schemes.
Construction company Downer paved the roads in partnership with recyclers Close the Loop — which developed the additive — and Redcycle, which collects plastic bags from supermarket recycling bins. “Soft plastics don’t disintegrate well in landfill,” Close the Loop Australia General Manager Nerida Mortlock told the ABC. “What happens here is it’s melted down into an additive. There’s no micro-plastics, there’s no pollution problems whatsoever.”
The companies hope it paves the way for a new standard in road construction.
“Together with our partners, we have proven that with thought leadership and a determined effort to make a positive difference, we have set a new benchmark in our industry when it comes to sustainability by creating new avenues to recycle and repurpose waste materials into new streams of use. It’s all about pulling product, not pushing waste,” Downer Executive General Manager for road services Dante Cremasco said in a press release when the Craigieburn road was paved.
Downer and the Australian Capital Territory government have also experimented with powder from toner cartridges and with recycled tyres. ACT roads minister Chris Steel said each tonne of asphalt for the territory’s $16 million initiative will contain about 800 plastic bags, 300 glass bottles, 18 used printer toner cartridges and 250 kilograms of reclaimed asphalt.
“If we are going to build a circular economy in Australia, then all governments have to act to establish markets for the re-use of materials like single-use plastic and glass for use in government and private projects,” Steel said.
It’s not only Aussie companies getting in on the act. Scottish firm MacRebur has built roads in the US, Australia, New Zealand, Turkey, Bahrain, and Slovakia, with South Africa next on its list. This year the company has opened a factory in Lockerbie, Scotland, to take rubbish that would have gone to landfill and convert it to pavements. A kilometre of road paved with MacRebur’s formula contains the same amount of plastic as 684,000 bottles or 1.8 million bags.
Dutch company VolkerWessels is in the process of perfecting its prefabricated PlasticRoad. It installed two 30-metre stretches of cycle track, in the towns of Zwolle and Giethoorn, last year. They each contain the equivalent of 618,000 drinking cups. The lightweight design has a hollow core, allowing for easy water drainage and the installation of cables, pipes, or solar panels. Its modular nature will save time on installation and repairs, as sections of road can be removed and replaced in a matter of minutes.
What started as two short roads at its Texas facility evolved into Dow Chemical partnering with the government of Indonesia, the Indian cities of Bangalore and Pune, and Thailand to reduce their waste outputs. Indonesia was the world’s second largest producer of plastic ocean waste, while Thailand ranked sixth. In 2017, Indonesia’s government set a goal of cutting its ocean waste by 70 per cent by 2025. With consultation from Dow, Indonesia built a 1.8-km road using 3.5 tonnes of plastics waste mixed with asphalt as a proof of concept. It was the first step into keeping enough waste to build 190,000 km of road out of the oceans. The Indian cities built 40 km of road using 100 tonnes of recycled materials. Dow’s agreement with Thailand will incorporate some of the country’s approximately 2 million tonnes of plastics waste into roads.
Strength and Flexibility
Aside from repurposing waste and keeping it out of landfill and the ocean, there are other benefits. Being mixed with plastic lowers the temperature of poured asphalt, reducing emissions. The resulting roads can withstand more extreme temperatures without cracking, reducing the number of potholes. The more flexible roads should also last longer than traditional asphalt roads.
Downer’s “warm” mix pours at about 40 degrees cooler than typical asphalt, saving 14 kilograms of carbon dioxide per every tonne of the mix, which can be approximately 50 per cent recycled material without compromising road quality. “When you go to really high levels of recycled content there’ll be some savings potentially too,” Downer’s Gana Varendran told the Canberra Times. “Every road is a quarry and it belongs to the ACT government and the community, so why not use this, why not treat it as quarry because you’re reusing road you’ve paid for?”
VolkerWessels says its road should be able to withstand temperature as low as minus-40 and as high as 80 degrees. Whilst roads made of a mix of plastic and asphalt will be more susceptible than that to temperature extremes, they will still expand less in hot weather and contract less in cold weather than traditional asphalt roads. “Our technology means that we can not only help solve the problem of plastic waste but also produce roads that cope better with changes in the weather, reducing cracks and potholes,” MacRebur CEO Tony McCartney told the BBC.
With fewer maintenance issues and a better ability bounce back, the roads will last longer. “What is also pleasing to see is that this sustainable, cost competitive road has a 65 per cent improvement in fatigue life and a superior resistance to deformation, making the road last longer, and allowing it to better handle heavy vehicle traffic,” Downer’s Cremasco said. Downer’s current mix should last about 15 per cent longer than other roads. VolkerWessels estimates its road could last 50 years — about three times the lifespan of asphalt roads — or more.
It will take significant investment in larger scale projects for plastic roads to make a lasting impact, but in creating a circular economy that uses recycled materials and produces no waste whilst actually reducing it, the product could be an environmental game-changer.