Drexel University is researching more environmentally friendly alternatives to road salt

Drexel researchers say self-heating concrete could replace road-damaging salt.

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A truck salts 76 East during a winter storm in Philadelphia.

A truck salts 76 East during a winter storm in Philadelphia. (Kimberly Paynter/WHYY)

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The Philadelphia region faces a second round of heavy snow on Friday, sending crews out to salt the roads.

Road salt and deicing chemicals prevent roads and sidewalks from becoming slippery, keeping drivers and pedestrians safe.

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However, these measures can have negative impacts to road structures, and the environment.

Chlorine-based salt, for instance, can chemically react with concrete, and essentially eat the road from the inside out. The freezing and thawing process also can damage roads.

However, researchers at Drexel University say they may have a solution. A team of scientists have developed a type of concrete that can release heat to melt snow and ice. After three years of testing, they say it could be an effective way to reduce road salt use. The Pennsylvania Department of Transportation uses an average of more than 800,000 tons of salt during the winter.

“This salt can interact with roads and create a lot of potholes, or, it can be destructive to the roads,”  said researcher Amir Farnam, an engineering professor at Drexel University. “And [then] we need to repair and maintain our roads. So, this can create a lot of financial burden in the state.”

Farnam said the idea for his project came from architecture that incorporates concrete slabs that store thermal energy to heat buildings.

Drexel’s technology works by absorbing solar thermal energy when the weather is warm, and releasing heat when there’s snow and ice.

Farnam said though constructing roads made out of the concrete could be expensive, it would save the state money in the long term because there would be fewer road repairs. He said the roads also would be more durable, because freezing and thawing processes would be reduced.

“If we consider the amount of financial benefits, that it’s going to help us to increase the durability of the roads, or lowering the amount of salt that we’re using, or snow plowing, or the labor during winter, it might be beneficial to start looking into this innovative technology.”

PennDOT currently spends about $161 million on prepping roads for winter weather.

Farnam said the concrete is also more environmentally friendly, as studies have found road salts can also impair waterways.

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He said because the technology relies on changing weather patterns, the concrete mix would need to be altered in order to be effective in regions such as Canada that have much longer periods of cold temperatures and snow.

Farnam and his team hope to complete their research at the end of the winter season. They also are interested in completing a cost benefit analysis, and a full life-cycle assessment.

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