Drivers and cyclists traveling over a small section of Old Stage Road in southern Chesterfield County may not realize that they’re riding over the state’s first “plastic road.” California and Missouri are two other states also studying this asphalt mixture.
Last September, just under a mile long section of the road was resurfaced with asphalt that contains more than 6,000 pounds of a binder product made from recycled plastic.
“Plastics have been used in roads for years, since the ‘70s, so that's not the new part,” said Toby McCartney, CEO of MacRebur, the company that developed the product. “But usually they produce brand new plastic to put into the road to enhance it. We found a way to use the old plastic that no one can do anything else with.”
Each year, the USA produces about 400 million tons of asphalt, according to the National Asphalt Pavement Organization. McCartney says that if their products were used to help produce that asphalt, “we would help save just over one million tons of plastic going to landfill or incineration, and it would divert the equivalent of 600,000 single-use plastic bags away from landfills.”
In traditional asphalt, a mixture of gravel, sand and other fillers are bound together by a petroleum-based hydrocarbon called bitumen. That’s the black, sticky, oily, smelly stuff people see when roads are being paved.
It’s found in deposits such as oil sands and pitch lakes but is primarily produced as a residue when crude oil is distilled. MacRebur’s “plastic road” reduces the amount of bitumen needed for asphalt.
“We are turning the plastic into its original, oil-based state and binding it to the stone with the help of our activator,” McCartney said, adding that his product reduces the amount of fossil fuel used when making asphalt. “It’s not a case of burying rubbish in our roads. In fact, at the end of their life, our roads can be recycled so the plastic waste is used over and over again.”
However, McCartney says he actually got the idea while watching people in India doing a version of burying rubbish into roads. He watched groups of people going to landfill sites and rubbish dumps to gather waste.
“One of the things that they were doing was picking out loads of old waste plastics, putting it into potholes,” McCartney said. Then they would pour diesel fuel over and light it on fire. “And all the plastic would melt down to form a seal in the hole. I thought there you go, there's a solution.”
MacRebur’s binder product, which McCartney says is a performance enhancer that’s meant to make the binding agent work better, caught the attention of people at the Virginia Department of Transportation, like senior research scientist Jhony Habbouche. He said VDOT has been moving to make its asphalt production more green for years, which includes using recycled materials.
“We've done a huge amount of research on and actual implementation for VDOT, including [using] recycled asphalt pavement,” Habbouche said, adding that MacRebur’s product is one of many they’re looking at.
Habbouche says back in 1994, two sections of road in Fredericksburg contained some plastic, “but they were using the old mix design.” And, VDOT also combined a kind of plastic with some modifiers they were testing back in 2015.
Habbouche, whose main job is as a pavement resource scientist, said the numbers around how much plastics end up in landfills is staggering.
“If you go back to 2017, we have 36 million tons of plastics. Only 3 million of them were recycled,” Habbouche said. “But you have over 75% stacked in a landfill. So the numbers keep on getting up and up and up.”
Part of the research Habbouche and other scientists at VDOT are doing includes evaluating if MacRebur’s plastic-derived binder, well, binds in place for a long time.
“What are the limits, constraints,” said Habbouche. “You're subjecting these materials to high heat and things like that.”
He said his team is also looking at any potential environmental impacts, including stormwater runoff of any microplastics.
“Safety is a big thing that we look at. We take this seriously,” Habbouche said. “And as much as we kind of encourage recycling, we want to make sure we're doing it the right way.”
Habbouche said it’s an ongoing project that gets evaluated from both the lab and from field performance.
“We've had some preliminary data right now. And we're looking to finalize our testing hopefully by the summer,” he said. “And that kind of gives us information, fundamental properties, [and] characteristic of the material.”
Habbouche said it’s too early to determine what the cost for using MacRebur’s product would be since the project is still in its early stages. But he did say that VDOT wouldn’t need to start any new paving practices or buy new equipment.
“We hope, and according to some preliminary results, that in the future, it will be cost effective,” Habbouche said.
McCartney said if his product is successful, VDOT will not technically be his client. But he says they could still see savings.
“It's the asphalt manufacturers that we help to reduce their costs because all of our products are bitumen replacement products,” McCartney said. “Because our waste plastic products are cheaper than the bitumen that we put into roads…the asphalt manufacturers save the money and hopefully pass that on to the likes of VDOT.”
Both McCartney and Habbouche said their goal is to source wasted plastic locally.
“I would rather start with a kind of recycled plastic waste or the trash that we have,” Habbouche said. “I believe this will be more effective. This takes a lot of work. And it's very challenging, because processing that is a game changer.”
Once all the data is analyzed, then VDOT can make a decision about incorporating MacRebur’s product on a regular basis – but that’s a long way off.
“We're three or four or five months into it,” Habbouche said. “I visited it between Christmas and New Year [and] we saw a great performance. We're looking to do a yearly monitoring, hopefully for the next 4, 5, 6, 7 years.”
