Plastic roads prove to be the real deal
Maybe recycling has always been in Larry Dietrich’s blood. Or maybe life just has a way of bringing you back to where you started.
Today a project services manager at Shell Polymers, Larry was once a kid growing up in southeastern Washington state. The family business — started by his grandfather — was the local landfill. But Larry had no intention of following in his forebearer’s footsteps.
“Believe me,” Larry says, “when I was a kid, I had zero interest in garbage.”
That remained true for the next few decades. Larry earned his degree in finance, then worked as a CPA for a number of years. Next, he took a job at a Houston-based Australian oil company, implementing an SAP software system. That turned into a 10-year stint as an IT consultant, which ultimately led to a consulting gig at Shell.
Larry was hired on full-time at Shell in 2007, and the next decade took him from Houston to the Netherlands to London to Monaca, Pennsylvania. And that’s where the story takes us back to his family business — or more specifically, to recycled plastic.
Featured Partner
- Transforms recycled plastics into specialty waxes and polymers used in asphalt roads, extruded plastic parts, roofing and other construction infrastructure applications
- Employs a process called molecular depolymerization that’s more resistant to cracking and rutting
A new idea for using old plastic
Larry was one of the first people to deploy to Monaca, which was previously home to a zinc smelting plant. The team on site in those initial days — appropriately called “Early Works” — was responsible for prepping the ground for construction of the new Shell Polymers petrochemicals complex.
“We essentially converted a site contaminated from 80 years of smelting zinc into a site Shell
could develop as if it were a greenfield location,” Larry says. “We wanted them to be able to come in and build as if building on virgin land.”
That included environmental remediation, excavation of more than 7 million cubic yards of earth, construction of temporary facilities and docks, and relocation of power lines.
Once site prep was complete, construction of the plant and associated infrastructure got underway. By then, Larry had moved into the role of project services manager for polyethylene. One day, his former boss — now sustainability manager for Shell Polymers — visited Monaca to give a presentation. Larry decided to attend in person to say hello.
“He talked about this idea of putting reclaimed plastic into the roads here,” Larry says. “I thought that was really interesting, because one of our goals is to support the plastic circular economy.”
(Real)ationships matter
After the presentation, Larry pulled his former boss aside and explained that he’d developed a good relationship with the local paving contractor during Early Works. Should he reach out to his contacts and see what was possible?
The answer was a resounding “yes.” So Larry started working his phone and email. Shell Bitumen in Europe provided recommendations on suppliers who were experts in using reclaimed polymer in asphalt. That led to a conversation with a company called GREENMANTRA Technologies.
Based in Ontario, Canada, GREENMANTRA is a leader in chemical recycling (also known as advanced recycling) that transforms recycled plastics into specialty waxes and polymers. The company’s products are used not just in asphalt roads but also in extruded plastic parts, roofing and other construction infrastructure applications.
“Typically, you hear horror stories about using reclaimed plastic in roads,” Larry says. “Probably because someone ground up soda bottles and threw them in the mix to see what would happen. What happens is that plastic and oil don’t mix. When the road heats up, plastic and oil separate, plastic rises to the surface, and the road essentially disintegrates.”
What interested Larry about GREENMANTRA was that the company’s approach — molecular depolymerization — was totally different.
“They depolymerize the polymer — cutting into the hydrocarbon chain so it produces a wax,” he says. “Wax has all sorts of interesting properties when it binds with the oil that you put into asphalt. It’s more robust. It’s more resistant to cracking and rutting. Those are the qualities you want in a road.”
Confident he’d found the right solution, Larry next reached out to Lindy Paving, the local firm he’d developed a close relationship with during Early Works. Could the team there make this recycled-plastic-modified (RPM) asphalt work in the roads on site?
“They had a lab, so we sent them some samples and they mixed various recipes,” Larry says. “Some things looked good, and some things didn’t. So they suggested we lay down some asphalt to see what happened in real life.”
Results proven in the real world
Larry and his team got the go-ahead to lay two test strips on site: one featuring traditional asphalt and the other an experimental performance modifier derived exclusively from post-consumer polyethylene and polypropylene. The plan was to monitor and compare performance over the course of six weeks.
That was early March 2020.
“Lindy paved the test strips on a Saturday morning, and we were all sitting around eating doughnuts and talking about this thing called Covid,” Larry says. “Five days later, our entire site shut down and so did the rest of the world.”
Due to the shutdown, the team ended up gathering more than a year’s worth of performance data — including an entire summer and winter when massive construction equipment was rumbling over the asphalt strips.
The result? The RPM asphalt outperformed the control strip, and the team made the decision to use it to pave the remaining six miles of roads and 47,000 square yards of parking lots on site. In the end, the project reused post-consumer polyethylene in a volume equivalent to that of 3 million plastic grocery bags.
“If it was that impactful on such a small site,” Larry says, “just imagine what repaving a 20-mile or more stretch of interstate highway could do.”
That’s not just idle talk. Shell’s roads engineer issued a document allowing the use of RPM asphalt at any Shell location around the world. In 2021, Larry and his colleagues had the chance to speak about the technology with the Pennsylvania Asphalt Pavers Association, National Center for Asphalt Technology and Pennsylvania Department of Transportation, along with various government officials. And organizations everywhere from northern Canada and rural Virginia to the Gulf Coast of Texas and the Middle East currently are testing GREENMANTRA’s solutions.
This could turn into millions and millions of pounds of waste diverted from landfills.
“It’s a win-win. We’re keeping plastic out of the trash and converting it into a product that’s not just usable but also makes roads last longer,” Larry says. “That’s something I can be proud of and something Shell can be proud of.”
It’s something we bet Larry’s landfill-owning grandfather would be proud of, too.