Conductive concrete

Die Anwendungsmöglichkeiten von leitfähigem Beton sind groß. So ist es beispielsweise möglich, im Winter Eis und Schnee von Gebäuden, Brücken usw. zu schmelzen und damit Materialschäden und Funktionsausfälle zu verringern.

A 200-square-foot slab of seemingly ordinary concrete sits just outside the Peter Kiewit Institute as snowflakes begin parachuting toward Omaha on a frigid afternoon in late December. The snow accumulates on the grass surrounding the slab and initially clings to the concrete, too. But as the minutes pass and the snow begins melting from only its surface, the slab reveals its secret: Like razors, stoves and guitars before it, this concrete has gone electric

Its designer, UNL professor of civil engineering Chris Tuan, has added a pinch of steel shavings and a dash of carbon particles to a recipe that has literally been set in concrete for centuries. Though the newest ingredients constitute just 20 percent of Tuan’s otherwise standard concrete mixture, they conduct enough electricity to melt ice and snow in the worst winter storms while remaining safe to the touch. Tuan’s research team demonstrates the concrete’s de-icing performance to the Federal Aviation Administration during a testing phase that runs through March 2016. If the FAA is satisfied with the results, Tuan said the administration 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,” Tuan said. “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. ...”

A unique bridge that resides about 15 miles south of Lincoln has given Tuan reason to feel confident . In 2002, Tuan and the Nebraska Department of Roads made the 150-foot Roca Spur Bridge the world’s first to incorporate conductive concrete. Inlaid with 52 conductive slabs that have successfully de-iced its surface for more than a decade, the bridge exemplifies the sort of targeted site that Tuan envisions for the technology.

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