What kinds of deicers will not damage concrete?
All common chemical deicers produce, by physical action, some salt scaling on non-air-entrained concrete. Concrete that is adequately protected with an amount of air sufficient for the maximum size of aggregate used (See ACI 302 Standard) will withstand this physical attack throughout its normal life. Deicers may also have a chemical effect on the materials with which they come in contact: Sodium chloride has little chemical effect on concrete but will damage lawns and shrubs and promote corrosion of metal. Calcium chloride has little chemical effect on concrete, lawns or shrubs but causes corrosion of exposed metal. (Reinforcement steel having an adequate amount of concrete cover and no exposure from cracking in the concrete is protected from attack.) Ammonium nitrate or sulfate is beneficial to most trees and shrubs but attacks concrete chemically and may cause its complete destruction. Urea, although expensive, does not damage concrete, lawns, shrubs or metal.