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Next Weather Investigates: Paving the road to a greener future

Minnesota engineers working to pave a greener future
Minnesota engineers working to pave a greener future 02:26

MONTICELLO -- A stretch of road near Interstate 94 in Monticello is a test lab of sorts. The goal is to find a durable road paving material with a lower carbon footprint.

"We're trying to use less cement in the concrete," said Glenn Engstrom, MnDOT's director of the office of materials and road research.

"It's replacing the cement, and the cement, they say, causes up to 8% of our CO2 emissions worldwide," said Ben Worel, MnROAD operations engineer.

It's kind of like figuring out the perfect baking recipe. Essentially, the crews are laying down 35 different types of materials, each are supposed to lower the carbon footprint of the paving process.

So what makes them "green" materials?

"Some of them actually capture the carbon over time, and that's what we're looking at," Engstrom said. 

Others, like the 3M product, use stuff in their mix that would have gone to the landfill.

"So this is the byproduct of roofing granules," said John Edwards, a 3M product development specialist. "This is the small stuff that's left over from the roofing granules."

Before any material hits the roads, engineers put in sensors. Next, they cover those sensors with the concrete mixture, and it helps them keep an eye on how the roads are holding up.

"It has to work," Engstrom said. "We can't afford premature failures."

But will it cost more money to go green?

"They're expensive now, but if we got into larger production, they'd be a lot cheaper," Engstrom said. "It's about long term costs, it's about costs to our environment, too, so we have to consider all those."

While it'll take a good year to get good data from this test, Minnesotans could soon see a new type of roadway near them.

"We're going to use it here and there. We've already talked to some cities and counties," Engstrom said. "Hennepin County was at our big open house last week, and they're looking at it."

Researchers and product developers from around the country were at the MnROAD test site this week. Engineers say that while the green materials are used around the country, they're not widespread.

Indeed, other states in the region are looking to Minnesota for ideas.

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