or gunite
Concrete applied by spraying.
Shotcrete is a mixture of portland cement , aggregate, and water conveyed by compressed air to a spray gun. For structural uses, shotcrete is usually sprayed over a framework of reinforcing bars and steel mesh. Because it can take any shape, is easily coloured, and can be sculpted after application, it is used for a variety of specialized structures, including artificial rock walls, zoo enclosures, canopies, shell structures, pools, and dams. It is sometimes used to bind the walls of tunnels.