Are All Concrete Swimming Pools Gunite?
Gunite is a term used to describe the material that is produced by the dry gun shotcrete method.
Gunite was invented in the early 1900′s by Carl Akeley.
Gunite is produced by forcing a dry sand and cement mixture through a hose with air pressure, Water is then injected into the mix at the end of the hose through a nozzle. Gunite was the original term coined by Akeley, trademarked in 1909. Carl was granted a patent for his “cement gun” and “gunite” in 1911.
Recognizing the market for the new invention, S.W. Traylor, a businessman from Allentown, Pennsylvania bought the rights to build the machines and do the “Gunite” construction work and formed the Cement Gun Company of Allentown, PA in 1915. “Gunite” then became a trademark of the Allentown Equipment Company.
The American Railway Engineering Association coined the term “Shotcrete” in the 1930’s to describe the process used to produce the trade name material “Gunite”. This term was also later adopted by the American Concrete Institute.
In the 1950′s methods for spraying “wet” or pre mixed concrete
Shotcrete Application
mixtures were devised. In the wet mix process, premixed concrete is pumped through a hose and air pressure is added at the nozzle to aid in the spraying of the mixture. Advantages of the wet mix process are water content of the mix is consistent throughout and larger aggregate can be added for strength.
Today the term “shotcrete” has become all inclusive used to describe any process in which cement is pneumatically placed or “sprayed” on the work area.
To add to the confusion, the term “shotcrete” is also used today to differentiate between the materials produced, the dry process producing “Gunite” and the wet process producing “Shotcrete”.
Many pool companies build swimming pools using the wet mix process, therefore their pools are really shotcrete, not gunite, although the term “gunite is often used generically to describe sprayed concrete pool shells.
Other methods for concrete pool construction include forming and pouring the pool walls or laying cement block for the pool walls then filling the block cavities with concrete.
