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Shotcrete is today an all-inclusive term that describes spraying concrete or mortar with either a dry or wet mix process. However, it may also sometimes be used to distinguish from gunite as a wet-mix. 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.
Gunite refers only to the dry-mix process, in which the dry cementitious mixture is blown through a hose to the nozzle, where the water is injected immediately prior to application. Gunite was the original term coined by Akeley, and trademarked in 1909, patented in North Carolina. The concrete is blasted by pneumatic pressure from a gun, hence "gun"-ite.
The term "Gunite" became the registered trade mark of Allentown the oldest manufacturer of gunite equipment. Other manufacturers were thus compelled to use other terminology to describe the process such as shotcrete, pneumatic concrete, guncrete, etc. Shotcrete emerged as the most commonly used term after gunite and after the later development of the wet process came to used be for both methods.
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