Electric Concrete Could De-Ice Roads

MONDAY, FEBRUARY 1, 2016


Researchers in Nebraska are hoping their electrified concrete will help drivers avoid the skids during winter months.

Chris Tuan, professor of civil engineering at the University of Nebraska-Lincoln, has developed a type of concrete with material in it to conduct electricity—and melt ice at the same time.

According to a statement the university released Jan. 22, Tuan has added steel shavings and carbon particles to otherwise ordinary concrete. Although the materials add up to just 20 percent of the concrete slab’s total mixture, it is just enough electricity to melt snow and ice while remaining safe to the touch.

Airport Concept

Tuan’s research team is demonstrating the concrete’s de-icing performance to the Federal Aviation Administration during a testing phase that runs through March 2016. If the FAA likes the results, Tuan said it will consider scaling up the tests by integrating the technology into the tarmac of a major U.S. airport.

“To my surprise, they don’t want to use it for the runways,” said Tuan. “What they need is the tarmac around the gated areas cleared, because they have so many carts to unload—luggage service, food service, trash service, fuel service—that all need to get into those areas.

“They said that if we can heat that kind of tarmac, then there would be (far fewer) weather-related delays,” continued Tuan. “We’re very optimistic.”

To test his project, Tuan is using a 200-square-foot slab of concrete outside the Peter Kiewit Institute. As flakes fell during a December Omaha squall, the snow accumulated on the grass surrounding the slab and initially clings to the concrete, too.

But as the minutes pass, the snow begins melting from only the concrete surface and the slab reveals its secret mixture.

Bridge Benefits

Other locations have given Tuan space to work, too.

In 2002, Tuan and the Nebraska Department of Roads made the 150-foot Roca Spur Bridge just 15 miles outside of Lincoln the world’s first to incorporate conductive concrete. Built with 52 conductive slabs, Tuan’s design has de-iced the bridge’s surface for more than a decade.

“Bridges always freeze up first, because they’re exposed to the elements on top and bottom,” said Tuan. “It’s not cost-effective to build entire roadways using conductive concrete, but you can use it at certain locations where you always get ice or have potholes.”

Potholes can come from salt or de-icing chemicals that corrode concrete and contaminate groundwater said Tuan. With conductive concrete, road crews could have a material with lower operating and maintenance costs.

Scott Schrage / University Communications

Chris Tuan, professor of civil engineering at the University of Nebraska-Lincoln, stands on a slab of conductive concrete that can carry enough electrical current to melt ice during winter storms.

The power required to thermally de-ice the Roca Spur Bridge during a three-day storm typically costs about $250—several times less than a truckload of chemicals, said Tuan. He also said the conductive concrete could be used in high-traffic intersections, exit ramps, driveways and sidewalks.

Industrial Espionage?

The electric concrete could have other uses, too.

By replacing the limestone and sand typically used in concrete with a mineral called magnetite, Tuan has shown that the mixture can shield against electromagnetic waves. The electromagnetic spectrum includes the radio-frequency waves transmitted and received by cellphones.

That means the concrete mixture could be useful to those concerned about becoming targets of industrial espionage, said Tuan. Using the magnetite-embedded concrete, Tuan and his colleagues have built a small structure in their laboratory that demonstrates the material’s shielding capabilities.

“We invite parties that are interested in the technology to go in there and try to use their cellphones,” said Tuan, who has patented his design through NUtech Ventures. “And they always receive a no-service message.”

Tuan developed the concrete with the assistance of Lim Nguyen, associate professor of electrical and computer engineering; Bing Chen, professor of electrical and computer engineering; and Sherif Yehia, a professor at the American University of Sharjah who earned his doctorate in civil engineering at UNL. The FAA is currently funding the team's research, which also received past support from the Nebraska Department of Roads.

   

Tagged categories: Aviation; Bridges; Concrete; Concrete defects; Environmental Controls; Government contracts; North America; Research; Roads/Highways; Substrates

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