The higher the concentration of salt, the lower the temperature at which freezing will occur. Generally, on the roads, salt loses its effectiveness once the temperature falls below -10 degrees centigrade.

At what temperature does salt not work on roads?

Rock salt is one of the most widely used road de-icers, but it’s not without critics. For one, rock salt does have its limits. If the temperature of the roadway is lower than about 15 degrees F (- 9 C), the salt won’t have any effect on the ice.

How long does it take for salt to work on ice?

It starts to melt as quickly as straight calcium, but lasts as long as other sodium/potash blends. Below is a graph of melt volumes produced in 20 minutes at -10°C (14°F). An ice melter’s granule size and surface area both affect the melting process.