Now, 'de-icing' concrete to help improve road safety

Scientists have developed a new type of concrete that can conduct electricity just enough to melt ice and snow, an advance that can provide a low-cost method to efficiently de-ice roads in winters and improve safety.
The researchers added steel shavings and carbon particles to standard concrete mixture. Though the newest ingredients constitute just 20 per cent of the mixture, they conduct enough electricity to melt ice and snow in the worst winter storms while remaining safe to the touch.
"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," said Chris Tuan, a professor at the University of Nebraska-Lincoln.

Potholes often originate from the liberal use of salt or de-icing chemicals that can corrode concrete and contaminate groundwater over time, Tuan said, making the conductive concrete an appealing alternative with lower operating and maintenance costs.
Tuan said the conductive concrete could also prove feasible for high-traffic intersections, exit ramps, driveways and sidewalks.
The technology offers another, very different application that does not even require electric current, the researchers said.

By replacing the limestone and sand typically used in concrete with a mineral called magnetite, Tuan has shown that the mixture can also shield against electromagnetic waves.
The electromagnetic spectrum includes the radiofrequency waves transmitted and received by cellphones, which Tuan said could make the concrete mixture useful to those concerned about becoming targets of industrial espionage.

Using the magnetite-embedded concrete, researchers have built a small structure in their laboratory that demonstrates the material's shielding capabilities.