Structural factor of concrete durability

At present, the durability of concrete is controlled by indirect indicators: by the quality of the materials used, of the reinforcing bar and admixtures, of the properties of the concrete mixture and its degree of compaction when designing reinforced concrete structures, of the duration and parameters of concrete care. Depending on the operation environment, the maximum allowable water/cement ratio value, the minimum allowable cement consumption and the concrete class for compressive strength are regulated. In some cases, the type of cement is limited; air entrainment, thickness and density of the protective layer of concrete, etc. are standardized. When using reinforced concrete structures in aggressive environments, the cause and degree of aggressive conditions is determined; the primary, secondary and special protection is designed. If the structure is operated without secondary protection, then most often the resulting criterion of concrete durability is its freeze-thaw resistance grade, which is determined by the microstructure of the hydrated phases of the cement.