what type salt do they use on the roads?
410578
Calcium chloride (CaCl2) I think.
248789
I know salt is ....\n\nEpsom salt i think is mostly used on the feet.
550319
salt water and fresh water.
184088
see if this helps\nhttp://firstgovsearch.gov/search?affiliate=noaa.gov&v%3Aproject=firstgov&query=salt+water+map
831148
Sea salt melts it quickly.\n\n\nPeace
182018
there are salt mines, just like coal mines, where salt comes from.  and salt flats...
346319
The salt water has the salt...\nThe sugar water has the sugar....
989514
In the desert it is to keep sagebrush from blowing into the road.\n\nIn the mountains it is to keep snow from blowing onto road.
933436
Boy, where to start?\n\nAll except dirt roads have a "base" or "road base" under them consisting of gravel or other mineral soil (not clay or silt).  It serves many purposes - it distributes the load to a wide area of underlying native soil (forces from a point load bear within a 45-degree angle so a 2-foot-thick base spread a load to a 4' x 4' area).  For an interstate, that can be 3 or 4 feet of gravel top by as much as a foot of concrete.\n\nAnd, in freezeing climates, the base separates and therefore protects the pavements from freeze-thaw movement of wet ground beneath.  In extremely cold climates with wet, fine-grained soils beneath, as much as 15 or 20 feet of gravel can be needed.  The Alaskan Highway through northern BC and Yukon is an example.\n\nAsphaltic versus portland-cement concrete (they are both concretes but are often called blacktop/macadam/tarmac versus concrete):  Portland cemernt is a stronger and more versatile binder - for instance, you can use rounded gravels.  Asphaltic concrete requires crushed stone with its angular pieces with greater surface area.  Also, asphaltic concrete is senstive to creep at very high temperatures.\n\nBoth AC and PCC are available in many, many forms.  Strength, temp resistance, salt tolerance, cure times, etc are by selected as needed.  And the aggregate (the gravel inside) is important.  The concrete mix can't be stronger than the aggregate used to make it.\n\nPCC is rarely used without steel reinforcement.  They make a great composite material because the concrete is very strong in compression while the steel is great in tension.  That's why you see workers threading together an intricate cage of steel before pouring a concrete roadbed nad especially before pouring a wall, column or bridge.\n\nThermal expansion/contraction - yes, many roadways are poured with expansion gaps - they cause rhythmic bumps as you drive along.  AC is often poured continuously.  The cracks that naturally form get bigger in the cold when the pavement contracts.\n\nHope that helps a bit.  Engineers spend a few semsters studying concrete design and some people spend their whole careers on it.
498851
There are all sorts of salts.\nIn common usage, 'salt' refers to sodium chloride. Table salt is refined sodium chloride together with various additives, e.g. anti-caking agents, iodides, etc.\nMarine/sea salt is sodium chloride from the solar evaporation of sea water. It contains associated impurities such as calcium sulphate and magnesium chloride.\nWhen I did a Google search with the term "sea salt"+"marine salt" most of the references were to do with products for marine aquariums, so I think that the phrase 'marine salt' is used to describe stuff mostly intended for aquariums whilst the term 'sea salt' is for human consumption. If this is the case then I would expect 'sea salt' to be more strictly controlled as far as imputities are concerned.
919611
Salt is carried into the oceans by the rivers that flow into it from land.  The river water absorbs salt from the rocks and minerals in the earth; the amount in the river water is small, so the water is not salty, but once it gets into the ocean the salt accumulates.  When ocean water evaporates back into the atmosphere, the salts stay behind and accumulate.  It takes thousands of years to build up to the present concentration, but it is still going on.
1020952
Saturated sodium chloride solution is highly polar, and will help to drive large amounts of water and other non-organic materials out of the organic solution (water will have a greater affinity for the salt solution, and will also attempt to dilute the salt).  The last traces of water will be grabbed by the anhydrous calcium chloride (though magnesium sulfate or sodium sulfate work better, as they are usually more granular).
513498
salt.\n\n(Sodium Chloride)
976344
The salt gets dissolved in the water.
950451
No, you are supposed to measure it for your science fair project.\n\nThe purpose would be "why do you want to know which makes ice melt faster?"\n\nThe reason is that street/road crews will put down salt, sand, or both on icy roads.  Why would they do that?  Maybe you should measure how slippery an icy surface is after it has salt applied, sand applied, or both applied.
379604
Rock salt and table salt ar two different ionic compounds.  Roack salt, calcium chloride, contains 3 ions: one calcium and 2 chloride ions.  Table salt has only 2 ions: one sodium and one chloride.\nSo who cares?  Well, the more ions (rock salt!) that are added to the ice (to make ice cream), the lower the freezing point of the ice will be.  Rock salt (3 ions) make the ice colder than the table salt (2 ions).  This is the only way the fatty moleculse of the cream can freeze into ice cream.  With table salt the ice just isn't cold enough.  The size of the salt crystals is not relevant.
87902
salt doesnt have as much effect on rust.... where rust comes from is oxygen reacting with the iron in your vehicle....\n\nso when water (H20) comes in contact with iron (Fe) it creates iron oxide...rust(FeO2)