Shotcrete is concrete (or sometimes mortar) conveyed through a hose and pneumatically projected at high velocity onto a surface, as a construction technique. Shotcrete is usually an all-inclusive term that can be used for both wet-mix and dry-mix versions. In the pool construction trade however, the term "shotcrete" refers to wet-mix and "gunite" refers to dry-mix; in this context, these two terms are not interchangeable (see "Shotcrete vs. gunite" discussion below). Shotcrete undergoes placement and compaction at the same time due to the force with which it is projected from the nozzle. It can be impacted onto any type or shape of surface, including vertical or overhead areas.