why are salts used in roads?

Question

Please be specific or informative, thanks! ^_^

WOW! Thanks for all the answers. They are very helpful.

By any chacne would the salt conbine with the water, or would it give off chlorine gas?

And why does salt lower the freezing point of water? Is it because the particles have so much energy and they heat up quickly?

I'm just so curious! Thanks! ^_^

Answer 1

The salt combines with the water in the ice and causes the ice to "melt" (turn back to liquid). The reason it melts is because salt water freezes at a lower temperature than fresh water. Just how much lower depends on the amount of salt added to the water. Wet roads are still slippery, but not as dangerous as roads that are ice-covered. Spreading both salt and sand on the road together is safer because the roughness of the sand gives tires more traction so they're less likely to slide and skid.

Answer 2

De-icing salt work by lowering the freezing point of water. A 23.3% concentration of salt water freezes at -6o F. These low freezing points are what makes salt useful.

Environmental impact :

A major concern in using chemicals-like salt- for winter road maintenance is environmental impact. Studies show that soils, vegetation, water, highway facilities, and vehicles are all affected, so it is very important to use chemicals wisely. Most soil and vegetation damage occurs within 60 feet of the road and is greatest close to the pavement.

De-icing chemicals are highly soluble and follow any water flow. Salt concentrations in Wisconsin's surface and ground water have increased since the early 1960's, the [Wisconsin] Department of Natural Resources [WDNR] reports, but aquatic life has not yet been affected that we know of. In drinking water sources, which the WDNR also monitors, salt concentrations are within recognized safe limits. In some reported cases, groundwater carrying de-icing chemicals has contaminated wells, but most of these apparently were caused by seepage from poor storage facilities.

De-icing chemicals can accelerate deterioration in concrete and steel structures. New construction methods are reducing this impact, but highways and bridges do suffer from chemical damage. Vehicle corrosion is also accelerated. Corrosion on vehicles and structures is estimated to be the largest cost impact of chloride based chemicals. Even relatively small amounts of chloride will significantly accelerate existing corrosion.

Answer 3

I don't know that salts are used in the road, but salts are used on the roads when it snows, since salt lowers the melting point of ice, causing the snow and ice to melt and run off of the road as liquid.

Answer 4

To alter the freezing point of water, salt water freezes at a lower temp. than fresh water. I think 6 to 18 degrees lower Fahrenheit

Answer 5

Because salt lowers the freezing temp of water. That way it needs to get a lot colder for it to freeze.

Answer 6

To lower the freezing point of ice and snow so that instead of ice on the road, you have just wet roads. Safety is the main reason.

Answer 7

They taste bland on their own...

Or they increase traction and the salt raises the melting point of water to make the snow/ice melt faster.

Answer 8

To make winter roads passable, highway personnel usually must either apply chemical de-icers to melt ice and snow or spread sand to provide traction.

Answer 9

Salts suck the moisture out of anything they are put on or in. I remember as a teenager some of my dopey friends making fake hickeys with an ice cube and some salt.

Answer 10

they use it on the road to melt the ice on it. a slowplow is not enough when the road has ice on it so by covering the road it salt it makes it safer for drivers.