Salt-impregnated asphalt de-ices itself
Living someplace that gets snow in the winter may have its perks, but the ice-melting salt that's spread on the roads isn't one of them. Besides the fact that it gets all over our cars and clothing, it also has to be reapplied throughout the winter, harming the environment in the process. If a new type of asphalt reaches production, however, salt-spreading may become a thing of the past.
Led by Dr. Seda Kizilel, a team of scientists at Turkey's Koc University mixed the salt potassium formate with a hydrophobic (water-repelling) polymer known as styrene-butadiene-styrene. That mixture was in turn added to bitumen, which is the main binding ingredient in asphalt. The resulting composite material was found to be just as tough as regular bitumen, yet its salt content "significantly delayed" the formation of ice on its surface.
In lab tests, it continued to release salt for a period of two months, still melting ice as it did so. The effect could reportedly last for much longer on an actual road, however. This would be because as the top layer of salt-depleted asphalt was worn away by traffic, fresh "salty" asphalt would be exposed from beneath.
With this in mind, the researchers believe that the salt-polymer composite asphalt could remain active for years. A paper on their research was recently published in the journal Industrial & Engineering Chemistry Research.Source: American Chemical Society