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Fracture-resistant concrete could help fight climate change

Smart Concrete
Posted at 11:39 AM, Mar 31, 2022

EVANSTON, Ill. — The bipartisan infrastructure deal will invest $110 billion of new funds for roads, bridges, and major projects over the next five years. But one scientist says rather than patching crumbling roads, it’s time to build better ones.

This time of year, construction crews around the country are busy repairing the damage left behind following months of fluctuating temperatures.

173,000 miles of our highways and major roads are in poor condition. As moisture seeps into the pavement and freezes, it expands, causing fractures that eventually lead to potholes.

Inside her laboratory, far from the stress of crumbling roads, scientist Ange-Therese Akono is trying to find a solution to the problem.

“How can we create a new type of cement that will be more resistant to water, so less porous - that will absorb less water?” asked Akono.

Akono, an associate professor of civil and environmental engineering at Northwestern University says longer-lasting material could save taxpayers billions in repairs and help reduce the carbon footprint.

She’s been using nano materials to develop what she calls ‘smart concrete.’

The concrete, which doesn’t have a snazzy name just yet, is a secret recipe that is combined with a nano compound called "graphene." It’s made up of a single layer of atoms arranged in a honeycomb lattice structure.

“We can think of a net that's going to be enmeshed with the grains of cement,” explained Akono. “And that mesh is really, really strong. So that's going to be preventing cracks from propagating. And it's going to hold the cement together.”

The mixture tightens up the pores of the concrete at a molecular level. The result is a more water and fracture-resistant building material that she says is more durable and highly functional.

“Right now, it's been 30% stronger than the average cement - or the classical cement that we've been using,” said Akono.

Better concrete could save billions.

According to AAA, 1 in 10 drivers sustains vehicle damage significant enough to need repairs after hitting a pothole. Those damages cost drivers $26.5 billion in 2021 alone.

In Indiana - ranked second in the nation for its problems with potholes - they’ve dedicated 155,000-man hours, used 12,200 tons of material and spent $5.7 million on pothole repairs in one recent year.

“When you have this cycle of freezing and thawing, then you're going to start propagating cracks. And then those micro-cracks then lead to larger macro cracks and potholes that we have,” said Akono.

Aside from the additional headaches caused by traffic congestion due to road repairs, Akono says stronger concrete would also benefit the environment.

Concrete is made with a cement mix. Fossil fuels are used to manufacture cement and the chemical process produces additional carbon dioxide which accounts for about 8% of all greenhouse gas emissions worldwide.

“If you can increase the strength, if you're going to increase the durability, then we can cut down the volume of concrete or cement needed to be able to achieve a given project,” said Akono.

Because in the end, sustainability is the smoothest road into the future, she says.