What Does Cementitious Coating Mean?
Cementitious coating refers to a coating that contains Portland cement as one of its components and is held on the surface by a binder. A cementitious coating provides corrosion resistance to substrates; for example, steel is protected from corrosion by maintaining the pH level above 4.0 at the metal/coating interface because steel corrodes at a lower rate in this pH range.
Proper selection of materials and their correct application is required for an effective cementitious coating.
Corrosionpedia Explains Cementitious Coating
Cementitious coating is a two component, thixotropic, cementitious modified polymer coating. This coating provides high adhesion to both concrete and steel. This coating provides protection from the effects of aggressive acid gases, moisture and chlorides and also resists chemical attack on the concrete or other substrates. This coating forms a highly elastic hard and alkaline coating on the substrate. Cementitious coating protects concrete in sulfate contaminated ground conditions.
Surface preparation is essential before applying this coating. The surface should be free from mill scale, oil, grease and other chemical contaminants. The surface must be smoothed by sandblasting and the coating should be applied without delay after surface preparation. An intercoat can be used if adhesion is lacking between the substrate and the coating. Coating thickness can be from 1/16 to 1/2 inch (1.5 to 13 mm). The coating is applied with various methods such as casting, troweling or spraying, but spraying is preferable due to its ability to properly drop coatings to substrates that have an unusual geometry or have sharp bends or corners.
Cementitious coating is useful for internal and external structural waterproofing of concrete and other mineral substrates. It is also useful for underground structures as well as roofs and decks. Cementitious coating can protect highways and coastal structures from a chlorides environment and enhance the durability of reinforced concrete.