Working Americans aren’t forced to stay home every time there’s a major snowstorm. And we owe that to the 20 million tons of salt dumped on our roads every winter to melt the snow and ice. The United States uses more than ten times as much salt on its roads as it does in its processed foods is just another way to look at that. That, of course, doesn’t count the salt used on driveways, sidewalks, walkways, parking lots, etc.
The use of rock salt for de-icing purposes first debuted in the U.S. on New Hampshire roads during the winter of 1938. The many advantages of using salt in the winter are likely why it’s been used ever since then, and remains the most popular de-icing product on the market today. It is easily accessible, affordable, and proven to be useful for melting snow/ice. Furthermore, a Marquette University study found that using salt reduced roadway accidents by 88 percent.
Residents in states like Hawaii and Florida don’t even have to worry about de-icing, but folks living in the area known as the “salt belt” aren’t as lucky. The salt belt consists of the 24 states that account for the vast majority of road salt used on asphalt and concrete surfaces. It’s not a shocker that Illinois and Wisconsin are parked right inside the salt belt.
While there are pros to using salt on asphalt and concrete, there are also many cons. Salting roads, parking lots, driveways, and sidewalks has become a necessary evil for many of us. If you live in the salt belt, salting during the wintertime is probably a no-brainer. However, you may want to make yourself aware of some of the many negative consequences that come with the use (and overuse) of rock salt for de-icing:
Nobody Likes a Salty Sedan
Road salt is a common cause for the corrosion of automobile parts. After driving on salted roads, many people park their vehicles in a garage, which allows the ice, snow, and salt to sit and rot away at the car’s structural components. This misstep accelerates rusting and causes adverse effects to the exhaust and muffler system, coil springs, piping, and frame. Most vehicle manufacturers target cars that are operated within salt belt states for recalls regarding corrosion problems.
What you can do:
- Keep the vehicle clean. Do what you can to wash off the salt residue shortly after each snow storm– or at least once a week
- Don’t use recycled water when washing the vehicle
- Avoid driving through deep snow that can pack against the bottom of your car (causing rust and driving hazards)
- Open and shut the doors, hatch, and trunk after washing to prevent from freezing shut
- Avoid driving in puddles because road salt collects in pools of water
- Cover your car when you know it’s about to snow
Salt & Concrete Go Together Like Toothpaste & Orange Juice
Disclaimer: Salt does not cause asphalt to deteriorate. If professionals correctly installed an asphalt driveway, parking lot, or roadway, the pavement’s integrity won’t be affected by salting. Salt will only affect asphalt that’s in rough condition and already deteriorating at a rapid pace. That’s not the case for concrete surfaces, however.
Winter isn’t due to part ways with us soon, and so neither are its icy and slippery conditions. Odds are, you’ve used salt on your concrete steps, sidewalks, or driveway. But that isn’t a great idea because over-salting can cause concrete to deteriorate quickly.
Salt causes corrosion to the rebar underneath the surface, which leads to crumbling and cracking on the main surface. The acidity in salt will break down the bonds that hold the concrete together. More importantly, bridges and overpasses reinforced with or made entirely of steel are also subject to corrosion from salt.
Since temperatures during winter fluctuate above and below rock salt’s snow-melt limit of 30 °F, freeze-thaw cycles may actually be worse with rock salt than without it. Once temperatures dip below 10 °F, the salt becomes ineffective and useless. Salt attracts water to itself, known as being ‘hygroscopic’. As you may know, concrete is excellent at absorbing water. Concrete that was salted previously is filled with salt-infused water. Salt-infused concrete can hold up to 10 percent extra water in it, that will expand when frozen next. All of this results in damages from too much pressure for the concrete to withstand.
According to the Proceedings of the National Academy of Sciences of the USA (PNAS), 37% of the drainage area of the contiguous U.S. has experienced an increase in salinity over the past 50 years. PNAS cites road salt as the primary source in the Midwest and Northeast regions of the United States. Rock road salt doesn’t just wash away into streams or rivers to eventually dissolve into the sea. In reality, a lot of it is retained locally, left to build up in ponds, lakes, soil, sediments, and, most unsettling, in groundwater.
Once salt enters an ecosystem, it can turn into an issue the grows with time. When salt finds its way into soil or a waterway, there’s no biological process that occurs to get rid of it. Salt can exit ecosystems through transport or getting diluted with newer fresher water, which can level out the salt content. However, isolated lakes and aquifers don’t have those options without the help from man; and the salt levels will only continue to increase.
Road salt can also damage your landscaping and the vegetation near roadways. The harm is shown clearly by browning and sparse branches on the side of the trees and plants that face a road, driveway, sidewalk, or parking lot. The salt negatively affects soil by displacing minerals or absorbing water.
Salting poses dangers to aquatic life as well. When salt finds it’s way into lakes or ponds, it then collects into a layer of salt at the very bottom. This salt layer then imprisons the necessary nutrients from getting to aquatic plants and animals. Elevated levels of salt in freshwater has detrimental effects on the reproduction and survival rates of a wide range of fish, amphibians, and invertebrates.
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Ultimately, road salt used in the winter saves lives. But experimentation and research into safe alternatives to road salt is important. Active research has been ongoing for years into using agricultural byproducts. Some municipalities across the salt belt have been experimenting with the use of cheese brine and beet juice for de-icing.
Posted by C. Butler on 2/13/20