Quote:
Originally Posted by Creek Jackson
Hey Don, what can you tell us about the different solutions that are applied to the road surface to keep it from freezing?
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I'll give ya a brief rundown without going into the specifics on how each substance works. I'm just a driver, not a chemist...lol.
They way we treat the highway is mostly based on weather and road surface temperature. There are sensors placed in the roadway in certain areas that give us air and surface temperatures, dew point....etc. We also have in each truck devices that measure both air and surface temperatures.
Liquid de-icer is used when the surface is dry and frost, freezing frog, and misty conditions with low surface temps are expected. Its like a preventative that is applied to the road before it sets up. It makes the road look wet. It is used when surface temps range from 32 - 20 degrees. Below 20 degrees it will freeze itself and isnt used.
Salt is used in various conditions and is cheaper than the liquid de-icer. Salt will be used when during the day the road has become wet from either melting snow or rain and is expected to freeze later. Salt is used when it starts to snow and the surface temp is not expected to drop below the lower 20's. No sense in melting the snow to just have it refreeze into black ice. During a snow storm, we'll apply salt in various amounts in an attempt to keep the roadway bare. But if its snowing harder than the salt can keep up, we'll stop applying and go to straight plowing. Once the snow storm stops, we'll go back to applying salt in an attempt to bare up the road. The salt is blended with a small amount of liquid de-icer to speed up the melting action.
Sand/salt mix is used when road temps are below 20 degrees. Its also used when snow gets compacted to a point that the plows aren't taking it off. Its used on black ice too. Its sand with a small percentage of salt mixed in. The salt helps the ice or snow to melt a little so the sand has something to grab onto. Otherwise it just gets blown off the road.
Sometimes when it has snowed and then freezing rain comes in you may see us plowing snow back onto the road. This is just to give a surface for you to drive on instead of ice.
Traffic plays a part too. It helps to spread the salt around and speed up melting. Thats why the lane traveled the most bares up quicker than the other.
Hope this is what you were looking for!