- LECA
Expanded clay pellets, most commonly known under the brand name LECA (acronym of "light expanded clay aggregate"), also known as "Hydroton" and under the non-proprietary terms "fired clay pebble", "grow rocks", "expanded clay (pellets)" or "hydrocorns", are small globes of burnt and puffed clay, used in construction and farming, and especially in
hydroponics .They are available in different sizes such as 4/8 ("4 to 8 mm in diameter"), 8/16, 10/20, 1/4 or 2/4. The drydensity of lightweight expanded clay aggregates is 300 to 500 kg/m3. [ [http://www.maxit-group.com/17848 Exclay - Lightweight expanded clay aggregates] ]
Originally a Danish innovation, LECA is now manufactured in
Algeria ,Argentina ,Austria ,Belgium ,China ,Czech Republic ,Denmark ,Egypt ,Finland ,Iran ,Italy ,Norway ,Portugal andSweden . [ [http://www.leca.ae/ leca.ae] ]Construction
Expanded clay pellets offer good insulation (low thermal conductivity coefficient), they are lightweight and heatproof. Due to their low weight and good shear strength it is used for lightweight fill in civil engineering structures to reduce settlement and reduce pressure on structures. [http://www.leca.ae/leca/Applications.htm Applications] ]
Applications
* insulation, especially on the roof
* support for elevated portions of flooring on existing slabs
* heat proofing of kilns, stoves and ovens
* construction of light fill (embankments) of highways on compressible subsoil
* reduction of earth pressure on retaining structures, e.g. bridge abutments
* additive—a so-called lightweight aggregate (LWA)—toconcrete
* terrarium/vivarium constructionFarming
Expanded clay pellets are anorganic, have a neutral
pH , and transport and store water. The gaps between the kernels provide a good aeration (oxygen transport) of the roots.Expanded clay pellets are used as a substrate in hydroculture / hydroponics, or as a soil additive. They can also be spread as a top layer over soil around plants to prevent the growth of unwanted weeds.
References
External links
*http://www.leca.dk
* [http://www.leca.dk/leca/we/home.nsf/page/generally-about-leca%C2%AE Short description]
* [http://www.oekotau.de/EasyGreen/engl/e_Hydroton.htm Hydroton]
* [http://www.arcillaexpandida.es/english.html Arexpan]
Wikimedia Foundation. 2010.
