Salt itself does not chemically react with concrete and cause damage. The damage is caused when ice melting salt lowers the freezing temperature of snow and ice turning it into water, the water enters the pores and cracks of the concrete, freezes and expands while inside. These frequent freezing and thaw cycles over the course of winter cause chipping and flaking on the surface. If you are going to use salt to melt snow and ice it is reccomended to keep your concrete protected with a high quality sealant. Otherwise sand / grit can be used for traction although it will not melt anything.
