Adding a little paraffin wax to a road’s concrete mix could help it melt snow and ice during winter storms, reports Drexel University researchers.
Led by Drexel College of Engineering assistant professor Yaghoob Farnam, the researchers explain how substances like paraffin oil can be used in concrete to store energy and release it as heat when a road needs a melt-off.
The Drexel university collaboration with Purdue University and Oregon State University, is among the first to demonstrate that using phase change materials as an environmentally friendly alternative can be just as effective as the standard salting and scraping methods.
Paraffin oil was the team’s material of choice for this endeavor because it is organic, widely available, chemically stable and relatively inexpensive.
Like all phase change materials, paraffin releases thermal energy when it changes its physical state, which means as temperatures drop and the oil begins to solidify it releases energy through latent heat of fusion.
To test its snow and ice-melting ability, the team created a set of concrete slabs — one with paraffin-filled pipes inside, one containing porous lightweight aggregate that had been infused with paraffin, and a third reference slab without paraffin. Each was sealed in an insulated container and then covered with about five inches of lab-made “snow.”
With temperatures inside the boxes held between 35-44 degrees Fahrenheit, both of the paraffin-treated slabs were able to completely melt the snow within the first 25 hours of testing, while the snow on the reference sample remained frozen.
The slab with the paraffin-filled tubes melted the snow slightly faster than the one composed of paraffin-treated aggregate.
In the group’s second experiment, in which the ambient air temperature in the box was lowered to freezing before the snow was added, the paraffin-treated aggregate was more effective than the embedded pipes. This is because the capillary pore pressure delayed the freezing of the paraffin, thus allowing it to release its heat energy over a longer period of time.
Image, video and content: Drexel University