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Expanded Clay Lightweight Aggregated Concrete. By Dulce Tanya Barrera MEEN 3344-Material Science 10/2/12. Classifications Properties of Lightweight Concrete. LIGHTWEIGHT AND INSULATING GROUT Density :600-1000 Kg/cm^3 Mechanical resistance: 25-100 Kg/m^2
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Expanded Clay Lightweight Aggregated Concrete By Dulce Tanya Barrera MEEN 3344-Material Science 10/2/12
Classifications Properties of Lightweight Concrete • LIGHTWEIGHT AND INSULATING GROUT • Density:600-1000 Kg/cm^3 • Mechanical resistance: 25-100 Kg/m^2 • NON-STRUCTURAL LIGHTWEIGHT CONCRETE • Density:1000-1400 Kg/cm^3 • Mechanical resistance: 100-150 Kg/m^2 • STRUCTURAL LIGHTWEIGHT CONCRETE • Density:1400-2000Kg/cm^3 • Mechanical resistance: higher than 150 Kg/m^2 (Richardson) • Classified based on the aggregates chosen to be in the mix. • give concrete specific properties, such as weight and efficiency. • Can end up being up to 88% lighter than traditional concretes. • According to ASTM regulations: • lightweight concretes are those mixtures that range from 60 to 100 pounds per cubic foot (pcf). Anything that is below 60 pcf is classified as super light weight concrete. • (NRMCA)
Clay Leca Clay Aggregates Features • Shape: Round • Color: shades of black and brown • Texture: • Coarse • Spongy cellular/Porus (IMPORTANT!) • This is what makes the clay light weight, because its surface area creates a lower density product • Mixes well with concrete • Freezing and High temperature Stability • Low Density (light) • High Resistance to pressure (incompressibility) (Lecaworld) Composition: Clay is typically moist fine grained natural material Shape: No specific shape Texture: Usually sticky and plastic textured Color: Depends on impurities, weathering, and mineralogical composition. (Lecaworld) • Clay Leca is used to expand the moisture retentive clay • makes more dry, less dense material (can mix better) • Gives it higher resistance to pressure as well as a lower density • (Lecaworld)
Expanded lightweight concrete process Pyro-processing: Clay to Leca • By heating shale, clay, or slate to temperatures in excess of 1800 to 2100 degrees F in a rotary kiln, ceramic aggregates are made . This causes the material to expand into an artificial lightweight aggregate. • “Their cellular pore system gives these lightweight aggregates their low-particle relative density” (Lecaworld)
Structural Projects Image from http://floatingbuilding.com Bridges, overpasses, Road Base High Rise Buildings What is it used for? Floor Slabs Image from http://www.concreteconstruction.net
Overall • There are three purposes for light weight concrete: • Lightweight and Insulating Grout, Non-Structural Lightweight Concrete, Structural Lightweight Concrete • Concrete is classified based on the aggregates chosen to be in the mix (gives concrete specific properties) • Through a process called pyroprocessing clay is turned into leca, which is then mixed with cement to create Expanded Clay light weight concrete. • Benefits and Down sides: • Expanded Clay lightweight concrete can prove to be significantly more expensive than normal weight concrete • Can be an economical solution because less concrete and steel beam material is utilized due to smaller columns being needed for the design to withhold. • Low permiability, concrete more recycleble, used to reduce a dead load • It is typically utilized in the construction of high rise buildings, floating structures, floor slabs and bridges. (Geofill, NRMCA, Laterlite, Richardson)
References • Richardson, Christopher. "lecaword.com." LECA. N.p., 28/09/09. Web. 2 Oct 2012. <http://lecaworld.com/whatis.html>. (Richardson) • Laterlite. "laterlite.com." General Catalogue 2007. Laterlite, 2007. Web. 2 Oct 2012. (<http://www.laterlite.com/upload/Documenti/Catalogue - Part 1 pages 17_MS.pdf>. (Laterlite) • NRMCA, . "http://www.nrmca.org." Concrete in Practice. What, Why, and How?. National Ready Mixed Concrete Assosiation, 2003. Web. 5 Sep 2012. <http://www.nrmca.org/aboutconcrete/cips/36p.pdf>. (NRMCA) • Geofill Cellular Concrete, . "http://www.geofill.com."GEOFILL CELLULAR CONCRETE OVERVIEW. GEOFILL CELLULAR CONCRETE, 2008. Web. 5 Sep 2012. <http://www.geofill.com/?gclid=CIfP78K9nrICFaNeTAodxzgAlw>. (Geofill)