Is salt on the roads really necessary ?

[eljefino]

Originally Posted By: KD0AXS
Originally Posted By: eljefino
When you get snowbanks you get freeze/thaw cycles and a little water on the shoulder that could sneak back into travel lanes. This causes "black ice" for the morning commute.


That's not black ice. Black ice is caused when temps are well below zero and the water vapor in exhaust from vehicles freezes on the pavement. This type of ice is essentially invisible, it appears to be dry pavement. That's where the term "black ice" came from. When it's that cold, salt is useless. At those temps, it's too cols for the salt to melt the ice.


https://en.wikipedia.org/wiki/Black_ice

The American Meteorological Society Glossary of Meteorology includes the definition of black ice as "a thin sheet of ice, relatively dark in appearance, [that] may form when light rain or drizzle falls on a road surface that is at a temperature below 0 °C."[3] Because it represents only a thin accumulation, black ice is highly transparent and thus difficult to see as compared with snow, frozen slush, or thicker ice layers. In addition, it often is interleaved with wet pavement, which is nearly identical in appearance.

So... why not both?

Regardless, snowmelt and refreeze is not white in color nor all that visible and the desire for salt to keep this problem under control on clear days between storms exists.

 

[Virtus_Probi]

I used to work in a building that was in a protected zone around an aquifier, no road salt allowed. The zone actually started partway down the street I took to work and the change in road conditions during the winter was dramatic...you'd go from clear pavement to 2-3 inches of bumpy ice and have to slow down from 35mph or so to 10-15mph. Even at those speeds, there would be lots of little fender benders from people sliding in turns or not stopping quickly enough when cars in front of them turned.

Calcium chloride cannot be used because that calcium might get into my DIT engine and cause LSPI.
;^)

 

[tig1]

Originally Posted By: eljefino
When you get snowbanks you get freeze/thaw cycles and a little water on the shoulder that could sneak back into travel lanes. This causes "black ice" for the morning commute. There's also a ton of traffic and sun in peoples' eyes, so you can't really wag your finger and say drive safer.

The sheen of salt on the roads is a near necessity for all the thaw/ refreeze cycles. Though I wonder how they'd get by if they used half as much.

Cars could be better designed. I had a 21 year old volvo with an original, local dealer name rivetted on the back that did fine in 21 Maine winters. It had decent quality metal in the chassis and (original) brake lines, and few "voids" to trap salt. Look at the bottom of a rear fender liner where it meets the rocker panel on most cars, and you'll find a little nook full of sand and dirt. This traps briny water. Body-on-frame trucks are bad because they have more nooks, and the frames aren't often super duper rust-proofed, galvanized dipped or whatever.


I lived in Maine for 10 years and completely agree with you. Thawing and refreezing at night is always a problem.

 

[dlayman]

Originally Posted By: Andy636
Originally Posted By: Merkava_4
Watching this video on youtube showing a Chevy S-10 severely rusted out, I question the need for salt. You buy a new car over in upstate New York and within 10 years the car is totally gutted out. I don't see why you people over there even bother buying new cars. Over here in California, my car is 15 years old and I'd have to look real hard to find a spec of rust on it. Must be nice you say? Yes it's nice.

The answer is NO, you can use Calcium Chloride that works even better than salt and that is 80 times less corrosive than salt and sand, and that can be used even at -42C.

Calcium chloride is used extensively over here in the cities instead of salt and all the cars look like giants sugar powdered muffins after a week.

The only problem is that is more expensive than salt and sand so your Gov would rather let the taxpayer pay out of it's own pocket for repairs and maybe a new car every few years instead of spending a bit more money on the CaCl2 for the common good.


Source of this corrosion info? The chloride ion is the attacking part of the Nacl molecule. Iron and steel are susceptible to corrosion from halides, of which chloride is an example, in general. Sodium or calcium being the counter cation should make no difference, they can both be correctly referred to as chloride salts.. Sand is not corrosive to metal, however it may cause paint damage, exposing the metal to the salt of other environmental factors.

 

[hattaresguy]

IDK my 10 year old Silverado wasn't terrible I just hosed it off once in awhile. I see no reason it won't last another 5-10 years rust wise at that point it will be junkyard ready anyway.

Up north its terrible though, I have seen 4-5 year old $60k trucks that looked like they were submerged in salt water most of their lives.

If I lived up north I'd lease.

Ford thinks they have the solution with aluminum, but the frames will still rot out so its not really a fix. They need to offer a "northern package", with stainless fuel and brake lines and a hot dipped galvanized frame like a boat trailer. I think a number of people would happily pay a good buck for it.

 

[HerrStig]

Originally Posted By: cat843
A lot of sand is also used in the northeast. Many times its a sand/salt mix. If it gets really cold, then the salt does not lower the melting point enough and the ice remains frozen and the only thing they can do is sand on top of the ice.

For the bulk of drivers, getting salt on their vehicles is not an issue. They will trade them in before any rust shows. But for people who keep vehicles for awhile they will need to get them treated with Krown or CarWell or FF if they want them to be near rust free at 10 yrs.
That "sand" does a great job on windshields, I think it's supplied by glass companies at no cost.

 

[SeaJay]

Do keep in mind, that vehicles do not turn into scrap at the first appearance of a small amount of rust. It takes an awful lot of rust to turn a vehicle into scrap or in need of serious repairs for structural integrity.

Many people get excited at the first sign of rust because of the appearance aspect. Having grown up in a family with limited funds in an area that had salted roads in the winter, and salt air from the nearby ocean we had rather old vehicles with significant rust. People probably figured out that we were cash poor from the rusty appearance of our one car, but those cars did keep going even with all of the rust.

 

[HerrStig]

The Swedes discovered some years ago that cars kept in garages in winter where the temp inside was above freezing sat in a corrosive bath of melted water and salt, it was better to keep them outside where the cold slowed down the chemical reactions.

 

[eljefino]

In the 90s they dealt with the ugly rusty rocker panel issue by putting plastic junk on top of them. Bubble Tauruses and Pontiac Grand Ams were the worst offenders.

When said plastic rocker extensions finally fall off, you should see what's trapped behind 'em.

 

[CT8]

Originally Posted By: Merkava_4
Watching this video on youtube showing a Chevy S-10 severely rusted out, I question the need for salt. You buy a new car over in upstate New York and within 10 years the car is totally gutted out. I don't see why you people over there even bother buying new cars. Over here in California, my car is 15 years old and I'd have to look real hard to find a spec of rust on it. Must be nice you say? Yes it's nice.

It hasn't rained in California for 16 years

 

[KGMtech]

Global Warming, might be our best solution to problems from salt use.

However, those presently in Snow Free zones might find their local environment too toasty for long-term enjoyment if the GW thing is fully realized. YMMV.

 

[Andy636]

Originally Posted By: dlayman


Source of this corrosion info? The chloride ion is the attacking part of the Nacl molecule. Iron and steel are susceptible to corrosion from halides, of which chloride is an example, in general. Sodium or calcium being the counter cation should make no difference, they can both be correctly referred to as chloride salts.. Sand is not corrosive to metal, however it may cause paint damage, exposing the metal to the salt of other environmental factors.


Forgot to mention one aspect; they use corrosion inhibited CaCl2.

I never said that sand is corrosive, but the test I've read compared the CaCl2 effect on steel, Al and Al-Mg with the sandblasting and corrosion effect at elevated speeds of the sand-salt mixture and it came about 80 times less.

I could go dig the links if you wish, but they are in Romanian

 

[dlayman]

Originally Posted By: HerrStig
The Swedes discovered some years ago that cars kept in garages in winter where the temp inside was above freezing sat in a corrosive bath of melted water and salt, it was better to keep them outside where the cold slowed down the chemical reactions.


Absolutely correct.. The melted ice (water) makes it much easier for the chloride to get into all the nooks and crannies where the rust starts, and then spreads from there.

 

[eljefino]

I am aghast about the slimy layer of briny water on my paint. I seethe just seeing it. It's around in December and March. I do share the opinion that dry salt, as seen in the coldest winter, is less problematic.

I see cars from Massachusetts, supposedly with less snow, worse off from salt. They get more messy, mixed-precip storms that need tons of salt and spend more time hovering around the freezing mark.

 

[KrisZ]

In southern Ontario it is absolutely necessary. They could use a bit less of it though.

 

[IndyIan]

Originally Posted By: KrisZ
In southern Ontario it is absolutely necessary. They could use a bit less of it though.

On my drive there is one moderately curvy section of hwy that just happens to be on the boundary between two municipalities. So the often there is salt on one side and not on the other... So I see more cars in the ditch there than anywhere else. Most drivers in the morning are regular commuters, but I guess some just don't notice?
With mandatory snow tires, I could see less salt being used overall, but for most drivers, they just want a wet not icy road to drive on. Rust or environment isn't an issue at that moment.

 

[dlayman]

Originally Posted By: Andy636
Originally Posted By: dlayman


Source of this corrosion info? The chloride ion is the attacking part of the Nacl molecule. Iron and steel are susceptible to corrosion from halides, of which chloride is an example, in general. Sodium or calcium being the counter cation should make no difference, they can both be correctly referred to as chloride salts.. Sand is not corrosive to metal, however it may cause paint damage, exposing the metal to the salt of other environmental factors.


Forgot to mention one aspect; they use corrosion inhibited CaCl2.

I never said that sand is corrosive, but the test I've read compared the CaCl2 effect on steel, Al and Al-Mg with the sandblasting and corrosion effect at elevated speeds of the sand-salt mixture and it came about 80 times less.

I could go dig the links if you wish, but they are in Romanian


Interesting. I wonder how they make it corrosion-inhibited. pH adjustment might have an effect, though probably not enough. I wonder if the mixture includes an amount of a sacrificial metal for the chloride to attack, rather than the iron and other metals of the vehicle.

We don't get sand here - we get even worse. Tiny gravel and stone chips ("cinders") which absolutely beat the tar out of the front of your car, letting it nice and exposed to the corrosive salt.

 

[Garak]

Get this - they use a lot of salt on our roads, but use a lot of calcium chloride on northern Saskatchewan roads in the summer to keep the dust down.

 

[Andy636]

Originally Posted By: Garak
Get this - they use a lot of salt on our roads, but use a lot of calcium chloride on northern Saskatchewan roads in the summer to keep the dust down.


That is correct, when it dries out it becomes sticky also reducing breaking distances.

 

[Andy636]

Originally Posted By: dlayman
Originally Posted By: Andy636
Originally Posted By: dlayman


Source of this corrosion info? The chloride ion is the attacking part of the Nacl molecule. Iron and steel are susceptible to corrosion from halides, of which chloride is an example, in general. Sodium or calcium being the counter cation should make no difference, they can both be correctly referred to as chloride salts.. Sand is not corrosive to metal, however it may cause paint damage, exposing the metal to the salt of other environmental factors.


Forgot to mention one aspect; they use corrosion inhibited CaCl2.

I never said that sand is corrosive, but the test I've read compared the CaCl2 effect on steel, Al and Al-Mg with the sandblasting and corrosion effect at elevated speeds of the sand-salt mixture and it came about 80 times less.

I could go dig the links if you wish, but they are in Romanian


Interesting. I wonder how they make it corrosion-inhibited. pH adjustment might have an effect, though probably not enough. I wonder if the mixture includes an amount of a sacrificial metal for the chloride to attack, rather than the iron and other metals of the vehicle.

We don't get sand here - we get even worse. Tiny gravel and stone chips ("cinders") which absolutely beat the tar out of the front of your car, letting it nice and exposed to the corrosive salt.


Don't know the exact formulation but the used substance also has manganese chloride, calcium hydroxide, and anhydride.

I know close to nothing about chemistry so I can't tell what's what...LOL...sorry...no Walter White here.