3. Hydration and intake
3.1 Plug
Products resulting from the thermal dehydration of gypsum have the property, when in contact with water, of regaining their initial degree of hydration and reconstituting gypsum. This phenomenon is known as gypsum setting. Several mechanisms have been proposed to describe this process, which takes place in three successive stages:
taking up water to reform the dihydrate ;
crystallization (the actual setting);
hardening.
Setting time: time elapsing between the start of mixing and the hardening of the plaster.
Early setting: the point at which plaster begins to crystallize...
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Hydration and intake
Manufacturing
Economic data
Gypsum around the world
The United States Bureau of Mines (USBM) estimates global gypsum reserves at 2,300 million tonnes. However, not all existing deposits have been identified, and potential resources are certainly higher.
The United States and Canada have the largest identified reserves, estimated at 730 and 450 million tonnes respectively. Europe has around 800 million tonnes of reserves...
Bibliography
Referrals
Standards and regulations
The adoption by the European Council on December 21 1988 of Directive 89-106 on "the approximation of laws, regulations and administrative provisions of the Member States relating to construction products" led manufacturers to speed up the process of standardizing their products within the European framework.
In 1990, the European Committee for Standardization (CEN) set up Technical Committee...
Organizations
National Association of Gypsum Industries (SNIP)
Union des métiers du plâtre et de l'isolation (UMPI / FFB) http://www.platreisolation.com
Union nationale artisanale métiers et techniques du plâtre (UNA -MTP/CAPEB)
European Gypsum Industry Association Eurogypsum
Producers and manufacturers
The table at 3 lists a number of French producers and manufacturers.
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