Good Thinking

Salt-impregnated asphalt de-ices itself

The material could keep roads ice-free, without the need for the spreading of salt
The material could keep roads ice-free, without the need for the spreading of salt

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

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10 comments
Bob Flint
So we gain the corrosive effect year round...even while it rains which it currently is doing up here in Montreal...DUMB, not to mention the leaching into the environment. What are these people thinking??
Daniel Stefanovic
Will it lower traction between road and tyre?
Purple-Stater
This is brilliant! Constant protection with a yearly salt release that likely is less than a single normal salting. Win-Win.
JimDelton
This is not a new idea, it's been around for years and a company out of Sweden, if memory serves, has been promoting it for a long time. It's also very expensive. About the only place it makes any sense at all is on a poorly designed road as a remedial measure over short distances until the road's design is fixed. There are much better ways to spend money.
Bruce H. Anderson
This new mixture may somehow need a temperature release mechanism. So maybe the bitumen expands in the summer, encapsulating the salts, and then exposes them as colder weather comes? And if it lasts "years" I hope they mean 20 years, because that is the typical lifespan of asphalt. Otherwise the coating may need refreshing.
Mr. Hensley Garlington
I still like the solar road idea better. I know it will require miracles to happen though. Still, this is an improvement. But as corrosive as sale is on our cars, I think we need other material improvements and/or coatings to reduce or eliminate that side effect.
Dan Parker
I'd hate to fall off a motorcycle at speed onto that stuff if you're one of those riders who doesn't like to wear all the gear. Road rash + salt = OUCH!!
RAMLOT
I see lots of deer strikes in the future of these roads as the creatures enjoy licking the road and then suddenly look up into the headlights.
pmshah
"the ice-melting salt that's spread on the roads isn't one of them"
Actually salt does nothing about melting the ice. What it does is lowers the freezing temperature of salty water, preventing slush from turning into ice. If salt could melt the ice then you would not have the phenomenon of ice bergs.
bergamot69
In the UK, where we get plenty of rain, a water-repellant surface could be the opposite of what we need- as sudden downpours can cause standing water in poorly drained locations.
Recent developments in both tarmac and concrete road systems have introduced porous road surfaces that can quickly absorb surface water, preventing puddles and standing water- obviously up to a point, ie when the ground becomes too saturated to absorb any more water.