Is replacing salt with sand for gritting a good idea?
Below a certain temperature salt is ineffective. In Canada, they use sand and gravel from freshly crushed rocks with some salt to keep it flowing freely. The salt is there to keep the sand from clumping up not because of it’s ability to lower the freeze point as it’s usually too cold for that. You’ll also notice that they have a lot more street cleaners in Canada to sweep up the excess sand and gravel once the streets have thawed out. The fact that salt dissolves into water is a problem because it increases the saline levels of any soil it gets washed into often rendering it infertile. If the salty water runs into the drains and out into the rivers, the increased saline levels plays havoc with the ecology of the rivers. Salt is easy to dissolve into water but difficult to get out of the water. This is why commercial car washers are required to capture all their runoff and either recycle the water or send them off for treatment rather than allow it to go into the drains.
