The search is on to find an alternative to salting the roads in winter. Salt helps melt the ice, but it also builds up in stream beds and drinking water.
Some cities, like Portland, have already moved away from salt and are opting for chemicals like calcium magnesium acetate. De-icing researcher Xianming Shi says at one point that was thought of as the silver bullet.
“Later on we learned a lot more about it,” he said. “The degradation in the water can also cause some water quality concerns. And also they’re not very effective when you’re dealing with colder temperatures.”
A study Shi did for the Oregon Department of Transportation found that a cold-temperature alternative to salt, magnesium chloride, corrodes concrete bridge decks.
Shi is with Washington State University at the Center for Environmentally Sustainable Transportation in Cold Climates. His lab is looking for a new generation of de-icers.
A recent study in Alaska found that blending salt with a by-product of vodka distilling is just as effective and reduces the amount of salt needed. Researchers hope to find a similar waste product in Washington -- maybe from wineries or biomass plants.
Shi has also worked on ice-resistant pavement and “smartplows” that sense how much salt is needed.
Shi said another factor driving the search? The price of salt is going up.