Self-Heating Concrete, Powered by Paraffin, Could Mean an End to Snow Shoveling
With paraffin, a phase-change material, these concrete slabs can keep themselves warm and snow-free automatically.
Researchers from Drexel University have a potential solution to the back-breaking labor of show shoveling: self-heating phase-change concrete capable of simply melting the snow as it lands.
"One way to extend the service life of a concrete surfaces, like roadways, is to help them maintain a surface temperature above freezing during the winter," explains associate professor Yaghoob "Amir" Farnam, of the work he and his team have been doing. "Preventing freezing and thawing and cutting back on the need for plowing and salting are good ways to keep the surface from deteriorating. So, our work is looking at how we can incorporate special materials in the concrete that help it to maintain a higher surface temperature when the ambient temperature around it drops."
Those additions: phase-change materials, developed over the past five years and now proven outside the lab for the first time. "We have demonstrated that our self-heating concrete is capable of melting snow on its own, using only the environmental daytime thermal energy — and doing it without the help of salt, shoveling or heating systems," Farnam explains. "This self-heating concrete is suitable for mountainous and northern regions in the U.S., such as Northeast Pennsylvania and Philadelphia, where there are suitable heating and cooling cycles in winter."
By adding low-temperature liquid paraffin to the concrete, the team was able to produce a slab that retains its strength while generating heat as the temperature falls — triggered by the paraffin switching from a liquid to a solid. In testing, which began in December 2021, the self-heating concrete proved capable of melting up to a quarter of an inch of snow per hour and maintaining itself above freezing for up to ten hours at a time. This, the team says, could deice roads even during heavy snow — without corrosive salt.
"We found that PCM-incorporated pavements cannot completely melt heavy snow accumulation — larger than 2 inches," co-lead Robin Deb admits. "It can, however, melt snowfalls less than two inches quite effectively. The PCM-incorporated slabs begin melting snow as soon as it starts to accumulate. And the gradual heat release can effectively deice a pavement's surface, which would eliminate the need to pre-salt before the heavy snowfall."
The team's work has been published in the Journal of Materials in Civil Engineering under closed-access terms; no timescale for commercialization has been provided.