First, the basic way de-icer works is to form brine by mixing with the water in ice and snow. This brine has a lower freezing point than water, so continues to melt the snow and ice until it becomes too diluted to function effectively.
The trouble is that this brine can seep into concrete, especially unsealed porous concrete. As temperatures get lower, the brine can refreeze, which causes cracking and other damage to the concrete. In the spring, you may experience a continuous freeze and thaw cycle, which can cause much more serious damage.
Secondly, rock salt will dissolve in the moisture left behind as it melts snow and ice. It too can then seep into your concrete, and when the climate becomes warmer and the moisture evaporates, the salt will recrystallize, causing the surface of the concrete to spall, or flake off. The process is also known as sub-florescence.
Third, if rebar metal is present in your concrete, you can face another problem – the de-icer and salt can corrode the metal, and the corrosion process can exert pressure on the surrounding concrete, making it crack and break down.
To mitigate such problems, we would advise that if possible, you shouldn’t use salt and de-icer on your concrete driveway or patio at all.
If you think you’ll need to, make sure your concrete is sealed properly, to cut down on the chance that brine/liquid could seep into the pores. And make sure you use small amounts as needed – don’t saturate the area with de-icer or salt.
Complete Driveway Designs also offer a sealing service on existing pattern imprinted concrete, whether we installed it or not.