These heated slabs can melt the snow right off the road, and although they cost quite a bit more than regular pavement, the use of industrial waste in their construction means that they’re not too pricey, either.
The gimmick here is that the concrete itself is conductive. When electricity runs through this concrete, it turns the whole road into a giant heater element. Forty eight volts is enough to power it, and if it is switched on before the snowstorm hits, the road surface is warm enough to stop snow settling in the first place.
"When the snow hits, it melts instantly so you don't have any accumulations," says the concrete’s co-inventor Chris Tuan, from the University of Nebraska, Lincoln.
The conductive concrete costs around $300 per cubic yard, compared to $120 per cubic yard for regular road. It would cost even more, but Tuan and his colleague Lim Nguyen added industrial waste products in the mix: steel powder and coke breeze, which is the small, dust-and-gravel-like leftovers from the coke-making process.
The cost isn’t as prohibitive as it might seem. The slabs would be used only in dangerous spots, or places prone to freezing. Tuan and Nguyen’s initial five-year test, begun back in 2003, took place on the Roca Spur Bridge outside Lincoln. Bridges are prone to freezing because they hang in the air, with no insulating earth below them. The slabs could also be used at intersections, exit ramps, and uphill roads, says City Lab’s Linda Poon. If current trials are successful, the FAA plans to use the slabs to make heated runways.
Once built, the heated road pays for itself. At two-cents per square foot, the running costs are much lower than paying people to spray salt and grit on the roads. The bridge in Nebraska cost $250 to power during a three-day-storm. And from an environmental point of view, it seems like flicking a switch might be a lot less intrusive than sending in fleets of gritting trucks.