Tuesday, December 8, 2009

God Bless Texas

Icy roads where I live this morning!

I just love technology that makes lives better. Long live research.

And why isn't it available here and now?

BLIZZARD-bound motorists won't have to wait for a salting truck or snow plow to clear the way if a "self-heating" road takes off.

While salting disperses ice and snow, the salty run-off corrodes the steel rods that reinforce roads and bridge decks, and also damages vehicles. With the US government striving to improve its road infrastructure after a fatal bridge collapse in Minnesota in 2007, new methods to clear snow without damaging structures are being sought.

One such method, being developed by Christiana Chang at the University of Houston, Texas, and colleagues is to incorporate electric heating elements into concrete roads or bridge decks. When cold weather is forecast, the element can be fired up to heat the road and prevent ice forming.... using sheets of carbon nano-fibers to heat the concrete.

Nanofibers comprise lengths of cone-shaped nano-tubes nested "like paper cups stacked on top of each other", says Chang. She bonded multiple layers of nano-fiber-embedded paper beneath a chunk of road concrete that was 10 centimeters thick and 25 square centimeters in area. It warmed from -10 °C to 0 °C in 2 hours while consuming just 6 watts of electrical power (Smart Materials and Structures, DOI: 10.1088/0964-1726/18/12/127001). Heating the block slowly reduced power consumption.

"It's an interesting technique, but scaling it up to cover whole roads will require enormous power," says Derek Carder, an engineer with the Transport Research Laboratory (TRL) in Wokingham, UK.

The Houston team, however, say that their method is [not too] complex and that as sheets of paper embedded with nano-fibers are already used to make electronic components, they are readily available and cheap. They add that savings made on salting and snowplow labor could make their low-maintenance design viable.

We probably won’t see entire roads covered in self-heating concrete any time soon, but spots known for being icy or snowy might be ideal locations for carbon nanofiber-based heat--the crest of hills, streets that are consistently shaded by buildings.

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