or wet mix process. However, shotcrete may also sometimes be used (incorrectly) to distinguish wet-mix from the dry-mix method. The term shotcrete was first defined by the American Railway Engineers Association (AREA) in the early 1930s. By 1951, shotcrete had become the official generic name of the sprayed concrete process—whether it utilizes the wet or dry process. Applications Shotcrete is commonly used to line tunnel walls, in mines, subways, and automobile tunnels. Fire-resistant shotcrete developed in Norway is used on the Marmaray tunnel in Istanbul. Shotcrete is used to reinforce both temporary and permanent excavations. It may be employed, in concert with lagging and other forms of earth anchor, to stabilize an excavation for an underground parking structure or hi-rise buildings during construction. This provides a large waterproof enclosure in which a structure can be erected. Once the structure is completed the area between its foundation and the shotcrete is backfilled and compacted. Shotcrete is also a viable means and method for placing structural concrete. Shotcrete is very useful in hard rock mining. Development of decline pathway to go underground is critical for movement of heavy machinery, miners, and material. Shotcrete helps make these paths safe from any ground fall. Also, the shotcrete is carried out much faster than the repair mixtures usual non-mechanized application. See also Cement Concrete Rebar Reinforced concrete Slurry wall Structural engineering The Flintstone House – an example of shotcrete housing construction Notes External links Concrete Tunnel construction