New Asphalt Additive Allows Pavement to Self De-Ice

[kernals12]

https://www.worldhighways.com/wh6/feature/new-additive-self-de-icing-asphalt-mixture-roads-winter

It works by lowering the freezing point of the asphalt. It reduces the need for road salt, and all the damage is does to cars, bridges, not to mention the environment. The lower freezing point also means fewer freeze thaw cycles.

[jeffandnicole]

I skimmed through the article, but I noticed that there is nothing mentioned about the cost or its availability. It seems, for being highly successful in some small test runs, that it's not being used. The concern then is why isn't it being used?  Is it pricey? Does it not last long? Does it decorate asphalt faster?

Transportation departments are always trying to find ways to reduce their winter time cough, but ultimately the largest expense of fighting snow and ice on the roads is the Manpower. Salt is cheap. If the ultimate price of this product is so costly that it outweighs the benefits of not using manpower, equipment and materials, it's not going to get much considerstion.

[kernals12]

I skimmed through the article, but I noticed that there is nothing mentioned about the cost or its availability. It seems, for being highly successful in some small test runs, that it's not being used. The concern then is why isn't it being used?  Is it pricey? Does it not last long? Does it decorate asphalt faster?

Transportation departments are always trying to find ways to reduce their winter time cough, but ultimately the largest expense of fighting snow and ice on the roads is the Manpower. Salt is cheap. If the ultimate price of this product is so costly that it outweighs the benefits of not using manpower, equipment and materials, it's not going to get much considerstion.

It's probably cost.

And while salt is nominally cheap, it's got many, many hidden costs. It damages concrete, rusts out cars, and causes a lot of water pollution. Several highways in New England were cancelled specifically out of fear that road salt would contaminate water supplies.

[kalvado]

Adding some calcium chloride to asphalt? Yeah, that would be holding I side pretty long, maybe a few months!
Looks remotely similar to sprinkling pavement with salty solution, but I suspect much less effective.

[kernals12]

Adding some calcium chloride to asphalt? Yeah, that would be holding I side pretty long, maybe a few months!
Looks remotely similar to sprinkling pavement with salty solution, but I suspect much less effective.

I don't see anything about calcium chloride

[kalvado]

Adding some calcium chloride to asphalt? Yeah, that would be holding I side pretty long, maybe a few months!
Looks remotely similar to sprinkling pavement with salty solution, but I suspect much less effective.

I don't see anything about calcium chloride

Do a bit of a search. The magic compound is 70% salt, 20% Calcium chloride,some other salts, and 1% siloxane to be added to asphalt

[froggie]

According to Cargill (who is the exclusive US supplier), "Winterpave" (as it's called) is effective at temperatures above 17F, and ineffective colder than that.  This is more or less similar to the road salts commonly in use.

It's worth noting that this isn't applied to the road like salt or brine...it's mixed into the asphalt at paving time, typically 4-5% of the aggregate weight (and replacing the sand otherwise used in asphalt production).  It's also only applied to the wearing course (i.e. the final asphalt layer).  Couldn't find anything on cost.

[Road Hog]

Seems to me like the salt will dissolve over time and make the asphalt more porous, leading to more potholes and deterioration.

[kalvado]

Seems to me like the salt will dissolve over time and make the asphalt more porous, leading to more potholes and deterioration.

Original claim is that additive is fully effective for at least 2 and up to 12 months. All those numbers are based on experiment with 7 pounds of asphalt mixture.

[kphoger]

Transportation departments are always trying to find ways to reduce their winter time

As my bridge engineer friend put it:  If you could invent a non-chloride way of keeping ice off roads, you could save the world trillions of dollars.

[hotdogPi]

Transportation departments are always trying to find ways to reduce their winter time

As my bridge engineer friend put it:  If you could invent a non-chloride way of keeping ice off roads, you could save the world trillions of dollars.

So what about other salts? Dissolving most things in water lowers its freezing point, so any salt without Cl that isn't too expensive would work.

[kernals12]

Transportation departments are always trying to find ways to reduce their winter time

As my bridge engineer friend put it:  If you could invent a non-chloride way of keeping ice off roads, you could save the world trillions of dollars.

How about carbon dioxide?

[kalvado]

Transportation departments are always trying to find ways to reduce their winter time

As my bridge engineer friend put it:  If you could invent a non-chloride way of keeping ice off roads, you could save the world trillions of dollars.

So what about other salts? Dissolving most things in water lowers its freezing point, so any salt without Cl that isn't too expensive would work.

What kind of salt do you have in mind? Unlike most other compounds, NaCl is mined directly, and is applied to roads in as-mined state (sans grinding). CaCl2 solution can be cheap as it is a byproduct of sugar processing; dry CaCl2 requires a lot of energy to dry. Anything else would cost quite a bit more.

And I doubt that other electrolites would be way better.