Shotcrete, gunite (/ˈɡʌnaɪt/), or sprayed concrete is concrete or mortar conveyed through a hose and pneumatically projected at high velocity onto a surface, as a construction technique, first used in 1907 invented by Carl Akeley. It is typically reinforced by conventional steel rods, steel mesh, or fibers. Shotcrete is usually an all-inclusive term for both the wet-mix and dry-mix versions invented by Akeley. In pool construction, however, shotcrete refers to wet mix and gunite to dry mix. In this context, these terms are not interchangeable.