The Science Behind Winter Gritting
Our customers often ask how salt works to keep drivers and pedestrians safe in frosty conditions. It’s not magic; salt has beneficial properties that could keep your employees and customers safe and secure this winter.
The bottom line is this: salt lowers the freezing point of water, and this is how it helps keep roads clear and safer for driving so that things keep moving despite the freeze. As the salt particles come into contact with the snow or ice, melting begins, and water is produced. This water containing dissolved salt is called “brine.” Brine freezes at lower temperatures than regular water, so it remains a liquid at below-freezing temperatures. The brine works its way further into the snow and ice and eventually down to the road surface. From here, brine can spread out under the ice, breaking the bond between the road surface and the ice. The remaining snow and ice float on top of the liquid brine, allowing traffic to quickly break down into slush.
Can it get too cold for salt to work? Salt is most effective up to temperatures of -5°C, after which time it becomes much less effective. It loses almost all effectiveness below -8°C, luckily these lows are pretty rare in the UK and even in these conditions, we continue to grit as the salt remains dormant ready to reactivate once temperatures lift to allow the chemical process to begin.
Why can I still see ice in the morning after gritting? Spreading salt on ice or snow will not automatically create a “back to black” result until there has been a foot or vehicle traffic to make the brine. When spread on top of ice or snow, each grain of salt will begin to melt the surrounding ice, working its way outwards. The brine works its way further into the snow and ice and eventually down to the road surface. Where snow falls on top of salt then it begins to melt the snow from beneath. Again vehicular trafficking will speed up this process. If you see slushing occurring at the main entrance to a site then this is evidence of the salt getting to work.
Ground Control has been keeping businesses trading 24/7 over the winter – whatever the weather – for more than fifteen years. Regardless of your service wishes or portfolio size, we will work with you to find the best Gritting and Snow Clearance packages to suit your everyday needs.
Have more questions or want to find out more about our service? Call us on 01277 598899, or email our team at gritting@ground-control.co.uk.
