Rock salt is often used as a gritting salt both residential and municipally for managing ice and to a lesser extent snow. It can help to stop snow settling but is better used after snow has been cleared to prevent paths, roads, driveways and steps icing over. It works by creating brine which is a solution of water and salt. This has a lower freezing point than ordinary water and putting salt whether it be white salt or rock salt, on ice will cause it to melt.
You don't have to use so much salt so that the ice is completely melted. A small amount of salt will weaken the ice allowing it to be easily removed by other methods. Many city councils will spread a mixture of sand and salt on roads during times of forecast snow and ice to help improve the traction of vehicles.
The mixture also helps the rock salt last longer as there can be severe shortages during the winter months. It's always worth being prepared for such shortages by stock piling gritting salt during the more clement weather. You will find it's also much cheaper as shortages caused by increased demands lead to higher prices. It's best to be prepared for the worst and it's best to bear in mind that if there is a shortage the local authories always get priority. So don't get caught out, buy rock salt in advance!
Rock salt is also good for use as an intensive weed killer. The sodium chloride when used in small quantities is probably the most environmentally friendly chemical weedkiller of all. The salt makes an excellent weed killer when it is diluted in water. Rock salt works the best although you can use table salt if you cannot find any rock salt. The salt spreads through the soil and gets absorbed into the roots and dries out the plant.
A word of WARNING. Salt will kill plants too and will make the ground unsuitable for future plant growth if used in large quantities. On a small scale, you can drop a small pinch of rock salt at the base of the undesirable plants and weeds. It will kill the plant but will dilute down to a harmless level in the next few rainfalls. On a larger scale, you can cover your gravel driveway with a good amount of weed killing salt and nothing will grow there for months.
De-icing rock salt is very practical and helps ensure the safety of drivers and anyone who has to venture out in the ice and snow on foot. Accident prevention is its most popular use, but it can even be used for decoration and health and well-being.