Could it be possible that future roads will be made of recycled materials? With increasing concerns about the waste created by construction, some are trying to lessen this issue or solve this problem by creating roads made out of recycled materials, often plastic. By doing so, they hope to create durable, longer-lasting roads while also reducing plastic waste.
What Are Recycled Roads?
While different companies are pursuing different approaches, the general idea is that waste plastic is melted and mixed with other ingredients for making road asphalt. Ordinarily, asphalt is composed of 90 to 95 percent aggregate — whether gravel, sand, or limestone — and 5 to 10 percent bitumen, the black gooey substance extracted from crude oil that binds the aggregate together. When contractors add waste plastics, they often replace just 4 to 10 percent of the bitumen, though some methods call for much more. Plastic roads, therefore, are not solid ribbons of plastic.
Despite the benefits of recycling plastic to make roads, some environmental concerns exist. One is that heating plastic for making asphalt can create carbon emissions, thus negating any emissions savings from using less bitumen. An October 2020 report by the U.S.-based National Asphalt Pavement Association (NAPA) acknowledged the risks of running the wrong plastics through an asphalt plant and advised against using recycled PVC in paving applications, as it releases toxins when heated. The report highlighted that PE is the primary plastic that could be incorporated safely into asphalt mixtures because of its low melting point, with polypropylene as a second viable candidate. Another concern about plastic roads is that they will shed microplastics, which is also not great for the environment.
What Impact Could Recycled Roads Have Globally?
There are many projects globally that are investigating creating roads by recycling plastic. One of these projects had the local road authorities near the UK city of Bath saving nearly €250,500 when repairing a 400m long section of the B3110 Midford Road. They achieved saving this much money by opting to recycle and strengthen in-situ the existing surface, instead of using conventional full depth pavement reconstruction. The council’s design group, working together with maintenance contractor Atkins, carried on this work.
The in-situ recycling also provided substantial environmental benefits, including a reduction in carbon dioxide emissions and reduced materials transportation and less use of newly extracted materials. This work also reduced disruption to the road network. Most of the cost-saving came from not having to extract and dispose of waste material in a special, licensed landfill. Instead, the existing road materials were re-used as the primary source of aggregates, and these were recycled and strengthened in-situ cutting waste. In addition, an estimated 12tonnes less CO2 emissions were achieved using in-situ recycling.
Similar road projects also took place in Ghana, after President Akufo-Addo called for Ghanaians to strive for a circular model to recycle and reuse as much plastic waste as they produce—about 1.1 million tons—by 2030. Barely 5 percent of the 5,000 tons of plastic that Ghanaians discard each day makes it to recycling facilities. The rest of the water often ends up in landfills, illegal dumps, streets, and waterways or is burned in open pits, poisoning the air. Heather Troutman, a program member of the Ghana National Plastic Action Partnership, noted that Ghana is a developing nation, and therefore it can be too expensive, complicated, and technical to recycle plastic. It’s often much easier just to burn it. But turning plastic into fishing nets, fuel, or paving material will give it value and make it less likely to be wanted. In a small nation like Ghana, where only twenty-three percent of roads are presently paved, waste plastic could go a long way.
Another project includes repaving a street in downtown L.A. with material made from recycled plastic bottles. TechniSoil Industrial designed the new process. It uses recycled PET plastic, the material used in plastic water bottles, to replace bitumen—a sludge leftover from oil refining that is used to hold asphalt together. The system uses a machine called a “recycling train” to grind the top few inches of a street, sends the material into a unit in the back that crushes the asphalt to a specific size, and mix it with liquid plastic. Basic recycling equipment already existed, but in the past, it was only possible to recycle lower layers of the road and not the top surface. This is because recycling the material made it lose strength. But the use of plastic makes the road even stronger than it was initially. In lab tests, the company has calculated that its roads can last eight to thirteen times longer than a standard road.
What Impact Could Recycled Roads Have In Canada & KW?
There have been several projects in Canada and KW that are focused on creating roads out of plastic, but one major project is by the company Last20. Last20 was started by Lauren Barnes, a business administration student in the Lazaridis School of Business and Economics, and her brother, Lucas, who graduated from the same program. Through their company, Last20, they’ve been selling t-shirts, each made from six plastic water bottles that have been shredded, melted, and extruded into yarn, and collecting and recycling thousands of bottles destined for the trash.
In Fall of 2019, Last20 launched a new business segment dedicated to plastic pavement called Last20 Upcycle. Last20 is working with chemical engineers from Wilfrid Laurier University and the University of Waterloo to develop proprietary plastic pellets made from recycled plastic materials that can be added into pavement blends. This new solution does not require new equipment, processes or training. In 2021, Last20 completed their very first batch trial test of our plastic pavement solution in Brantford, Ontario, with our strategic partners – CTA Lab, King Paving, Gedco, and their proprietary waste plastic source to upcycle over 600 lbs of waste LDPE into sustainable pavement. They will continue to monitor the ongoing impacts of our solution with Carleton University.
More and more projects are emerging with recycling and reusing plastic to be used in building roads. It’s highly possible that roads made of recycled materials, especially plastic, will become mainstream. Do you think recycled roads will be a bigger part of the future? Let us know by tagging us at @SustainableWat!