The resistance of concrete to freezing and deicing salts depends mainly on the durability of its outermost zones. The material properties of these outermost zones appear to be rather inhomogeneous. Thus, variability of material properties is inevitable in these zones. In addition, external influences may cause other inhomogeneities in the concrete, for example, gradients of water saturation, salt concentration, or temperature. Thermal gradients, especially those created by the temperature shock during the process of ice melting by means of deicing salts, can cause the development of internal stresses in the concrete. An estimation of the internal tensile stresses is determined on the basis of temperature shock experiments; they may reach the order of magnitude of the tensile strength of concrete under unfavorable circumstances (thickness of ice 0,5 mm and more; high salt concentration).