Even as we choke our world with plastic waste, there are people trying to address the problem – and one of the ways is by incorporating waste plastic into other materials such as the asphalt with which we pave roads. And it turns out that there is a lot more of this going on than I ever realized, as I discovered when I looked further into a story I read the other day
The Guardian reported on a project in the rapidly-growing area of Kollam in Kerala state in India. Fishermen collect plastic that is caught up in their nets and unload it at the harbour instead of throwing it back in the sea. Women’s self-help groups then sort it so it can be chopped up and sold to local construction companies to add to the road surfacing material.
This project began in 2017 and while it has attracted wide interest, has had its problems getting sustained financing. Now it is part of a massive $105-million project, just funded by the World Bank, to help Kerala state strengthen its waste management system – which is why the project seems to be in the news again.
Plastic waste is a staggering problem for Kerala. Almost 330 tons of plastic waste is generated each day, and it pollutes the ocean along Kerala’s 570-km coastline, which is famed for its pristine beaches, estuaries and wildlife, as well as 70% of the state’s water sources. Only a tiny amount of the plastic is collected and recycled.
In Kerala state, almost one million people depend on fishing for their livelihoods, and the state is one of India’s top fish producers, but ocean pollution has depressed catches. So you can see why the state’s fisheries minister created the Suchitwa Sagaram, or Clean Sea project, in Kollam in 2017.
Of the 80,000 kg of plastic waste collected from the seas off Kollam since then, more than half was used in laying 84 miles (135km) of road. More than 20 women worked in sorting and shredding the plastic, creating jobs for them in a traditionally male dominated industry.
Their salaries are paid from the purchase of shredded plastic by local construction companies who use it for road surfacing. Each kilometre of plastic road uses the equivalent of one million plastic bags, saving a ton of asphalt and cutting road construction costs by about 8–10% per kilometre. Adding plastic makes the roads more resilient in India’s extreme heat, says VK Lotus, an engineer with Kerala’s harbour engineering department.
Other fishing communities along the Kerala coast now want to start their own collection and recycling programs, and such scaling up could have a real impact, the Guardian says.
Using plastic waste in asphalt is not a new idea in India, which has installed 60,000 miles of such roads since the first one in Chennai in 2002, based on initial experimentation by a chemistry professor. In 2016, India made it mandatory to add waste plastic into bituminous roads.
Indonesia, Thailand, Saudi Arabia, Ghana, South Africa, Vietnam, Mexico, the Philippines, the USA, Canada, and the UK also have used recycled plastic in their roads. In 2018, Ghana announced an ambitious plan to recycle, by 2030, as much plastic waste as they produce each year (roughly 1.1 million tons), and such plastic roads may allow it to expand paved roads dramatically. The Netherlands has moved a step further on by creating bicycle paths and roads that are entirely made of plastic.
India, in fact, was the inspiration for the creation of a Scottish company that specializes in this work. When Toby McCartney, founder of MacRebur, was frustrated by potholes on his street, he remembered seeing workers in India filling potholes with waste plastic from landfills and then setting petrol on fire to seal them.
That led him to brainstorm how local rubbish could be incorporated into roads to make them stronger, longer lasting, and pothole resistant, thus effectively solving two problems at once. But it also saves emissions into the atmosphere, he says. Each ton of bitumen that is replaced by plastic saves a ton of CO2 emissions, not to mention using up the equivalent of 80,000 plastic bottles. And each kilometer of plastic road contains the weight of nearly 750,000 plastic bags.
Since 2017, when Cumbria County Council became the first UK highway authority to use MacRebur’s approach, its materials have been used in roads, paths, driveways and parking lots in Turkey, Japan, Saudi Arabia, Dubai, Australia, New Zealand and elsewhere, Yale Environment 360 reported in February this year.
An American company has gone a step further – it recycles the asphalt, too. TechniSoil Industrial uses a ‘recycling train’ to grind up the top few inches of a street, crushes the asphalt to a specific size, and then mixes it with liquid plastic made from recycled PET plastic. The company says its roads can last eight to 13 times longer than a standard road, saving cities money over the long-term, and reduces emissions by 90% in comparison with repaving the usual way because it doesn’t require trucks to haul away waste or bring in new asphalt.
“New synthetic binders are going to transform the global road construction or road rehabilitation marketplace, and they’re going to allow for roads to be 100% recycled,” says CEO Sean Weaver. “That’s always been the holy grail of the road construction market—could you recycle 100% of the top surface of the road, grind it up, crush it, and put it right back down, and have that be as durable as the original hot mixed asphalt road?”
In the Netherlands, PlasticRoad has ditched the asphalt entirely. Zwolle, just an hour from Amsterdam, became the first city in the world to have a truly plastic road in 2018, following two years of testing a pilot prototype that used recycled single-use plastic. The road was cheaper and faster to build than a traditional road, the company said. Zwolle also has a 30-meter bike path that includes sensors which collect data, space for services to run underneath, and its own stormwater management system. A second road was built in Giethoorn in 2018, intended to see how the plastic road responded in weak soil conditions.
The prefabricated construction material, which is four times lighter than traditional roads, snaps together rather like a child’s plastic bricks and thus construction is quick. It lasts two to three times longer than traditional roads, is impervious to weeds and weather, and needs little or no maintenance. Its hollow spaces can store water or cables and pipes, and the concept offers opportunities for further innovation such as solar heated roads, light poles, and traffic loop sensors.
Even Dow Chemical, the world’s largest plastics producer, has gotten on board. In 2017, it partnered with the Indonesian government to help with its goal of reducing plastic waste in the ocean by 70% by 2025, and incorporated 1,686 pounds of used plastic – equivalent to 120,000 plastic grocery bags – in its first US pilot project in Texas in 2019. Dow says it has now incorporated recycled plastic into more than 150 km of roads and parking lots in Europe, Latin America, North America, and Asia Pacific.
The idea of making our economy circular, so we reduce, reuse and recycle everything rather than dumping our waste in landfills, has caught on in the past few years. It has been accelerated by the decision of China, India, Indonesia and Malaysia to no longer accept our plastic waste.
Plastic roads may only make a dent in our world’s plastic waste problem. Only 9% of the 350 tons of plastic we produce each year is recycled, Yale Environment 360 observes. However, it does seem that such roads could be one of those ‘triple win’ solutions – recycling plastic waste; making our roads cheaper to build and maintain, longer lasting, and stronger; and reducing CO2 emissions to the atmosphere.
How Paving with Plastic Could Make a Dent in the Global Waste Problem. Yale Environment 360, Feb. 11, 2021
How a company is turning PET into durable asphalt. Plastics Recycling Update, Aug. 19, 2020
Los Angeles is testing ‘plastic asphalt’ that makes it possible to recycle roads. Fast Company, Oct. 24, 2019
Use of Plastic Additives in Asphalt Mixtures Increasing. Construction Pros, Nov. 2, 2020
Smart Cities: From Plastic Pollution to Plastic Roads. Interesting Engineering, Sep. 15, 2019
Net gains: how India trawlers’ plastic catch is helping to rebuild roads. The Guardian, Apr. 1, 2021.