- Rastra
Rastra is an insulating concrete form (IFC) used to make walls for buildings. It is composed of
concrete and thastyron. Thastyron is a mixture of plastic foam and binder that is composed of eighty-five percent recycled post consumerpolystyrene waste that are molded into blocks. The main components of rastra are cement, water and expanded polystyrene.Production
Rastra is
sustainable in its production because no energy is used in the curing process, and only one to threekilowatt hour (kWh) is required to make each block. After the blocks are trimmed to exact size the remaining debris is recycled to create new blocks. No byproducts are released in the production process that are considered a burden to the environment. [http://www.rastra.com RASTRA INSULATED CONCRETE FORM SYSTEM (ICF) Construction Building Blocks For Houses & Commercial Buildings ] ]Building
Rastra blocks come in different sizes, and can be easily cut with woodworking tools to form the desired shape. These blocks are commonly attached together with clamps or glue to form a grid-like system. Rebar is then run through the grid which is then it is filled with concrete.
History
Polystyrene concrete was invented in 1960.
BASF , a German chemical conglomerate originally created this product, but found no successful applications. An Austrian/Swiss based company modified the product and created what is known as Rastra.Fire Rating
As a thermal barrier rastra has a four hour fire rating with no flame spread and no smoke development. A five hour fire endurance test of a ten inch thick wall with temperatures exceeding two thousand degrees Fahrenheit on the face of the wall showed that the wall did not conduct heat. This lowers the number of health hazards during a fires and also makes building repairs easier afterwards.
Physical Properties
Thastyron has a
compressive strength of 56pound-force per square inch (psi) and atensile strength of 43 psi. Rastra has a low toxicity level. Rastra is highly frost, fungus, and mildew resistant. The sound insulation is greater then 50decibel (dB).Insulation
As a heat insulation rastra keeps a room at a constant temperature and evens out temperature changes both of which can lower energy use. It also has a low heat penetration depth.
References
External links
* [http://www.tile-tec.com/rastra.html Tile-Teck International]
* [http://www.zetatalk.com/shelter/tshlt13w.htm Troubled Times]
* [http://www.panelcrete.com/history.htm Panel Create]
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