A Recipe For Concrete That Can Withstand Road Salt Deterioration

Road salt, used in copious helpings each winter to protect them from ice and preserve safe driving conditions, is slowly degrading the concrete they’re made of. Engineers have known for some time that calcium chloride salt, commonly used as deicer, reacts with the calcium hydroxide in concrete to form a chemical byproduct that causes roadways to crumble. A civil engineer from Drexel University is working on a new recipe for concrete, using cast-off products from furnaces, that can hold its own against the forces of chemical erosion.

More than 900,000 tons of deicing salt is used each winter in Pennsylvania alone. While winters in the Northeast put pressure on departments of transportation to keep roads clear and deicer is an effective part of that process, it also contributes to the thousands of miles of roads that need to be patched and repaired each year.

Yaghoob Farnam, PhD, an assistant professor in Drexel’s College of Engineering and director of the Advanced and Sustainable Infrastructure Materials Research Group, is looking for a solution to this problem in the recipe for concrete. Farnam created a method for using fly ash, slag and silica fume — leftovers from coal furnaces and the smelting process — in a new concrete mix that is more durable because it doesn’t react with road salt. He recently published his findings in the journal of Cement and Concrete Composites.

“Many departments of transportation have reduced the amount of calcium chloride they use to melt ice and snow, even though it is very efficient at doing so — because it has also been found to be very destructive,” Farnam said. “This research proves that by using alternate cementitious materials to make concrete, they can avoid the destructive chemical reaction and continue to use calcium chloride.”

Continue reading at Drexel University.

Image via Drexel University.