Terrazzo is a composite material, poured in place or precast, used for floor and wall treatment. It consists of marble chips, quartz, granite, glass or other suitable materials, poured with cement binders (for chemical bonding), polymers (for physical bonding), or a combination of both. Metal strips divide parts, or color or material changes in patterns. Additional chips can be sprinkled over the mixture before adjustment. Once it is cured it is ground and finely smooth or otherwise finished to produce a uniform textured surface.
Video Terrazzo
History
Terrazzo right
Although terrazzo history can be traced back to the ancient Egyptian mosaic, its predecessor came from Italy. The terrazzo form used today comes partly from the 18th century pavimento alla Veneziana (the Venetian sidewalk) and seminato cheaper seminato. Pavimento alla Veneziana has workers place marble fragments next to each other in a mortar. Terrazzo is also linked to the seminato technique where workers throw larger chips of marble into cement which is then milled and polished. Together, this method creates a generic terrazzo form that involves bits of stone bound to a cement bed. Terrazzo was first introduced in the United States in the late 1890s, but did not reach its popularity until the 1920s. Until then the hands are polished with a long handled device called galleras . Because of the possibility of cracking, terrazzo is used on a small scale compared to the large expanse we see today. Two discoveries resulted in an increase in popularity: a divider strip and an electric grinding machine. Discovery strip divider by L. Del Turco and Bros. in 1924 contained terrazzo fracture by allowing greater space material to expand and shrink after installation. This discovery makes terrazzo a durable and reliable material in addition to allowing for further design work on the floor. Installers use the separation strips as a guide as they work with different colored terrazzo. Electric milling machines and mechanization of the production process reduce the cost and time to make the terrazzo an affordable flooring option.
The Art Deco and Moderne styles of the 1920s to the 1940s favored the terrazzo with dividers allowing straight or curved lines that increased the decorative potential. The popularity of terrazzo led to an increase in installers in the 1920s. The National Terrazzo and Mosaic Organization was formed in 1931 to further professionalize the practice of terrazzo installations. One of the most famous terrazzo examples is the Hollywood Walk of Fame. Created in 1958, celebrities in the form of a star terrazzo featuring their names.
Archaeological use of the term
Archaeologists have adopted the term terrazzo to describe the floor of the early Neolithic buildings (VAT A and B, about 9,000-8,000 BC) in Western Asia constructed from burnt, red chalk and clay with ocher and polished. The crushed limestone rocks embedded make it look a little dappled. The use of fire to produce baked lime, which is also used for hafting tools, precedes pottery production fired by nearly a thousand years. In the early Neolithic settlement ÃÆ'â € ayÃÆ'¶nÃÆ'¼ in eastern Turkey about 90 m 2 (970Ã, sqÃ, ft) of the terrazzo floor has been found. Floor of VN B settlement in Neval? ÃÆ' â €? Ori measures about 80 m 2 (860 sqÃ, ft). They are 15 cm (5.9 inches) thick, and contain about 10-15% lime.
This floor is almost impenetrable to moisture and is very durable, but its construction involves high energy inputs. Gourdin and Kingery (1975) estimated that the production of a certain amount of chalk requires about five times the amount of wood. Recent experiments by Affonso and Pernicka have shown that only twice the required amount, but it will still amount to 4.5 tons of dry wood metric to the floor in ÃÆ' â € ¡ayÃÆ'¶nÃÆ'¼. Other sites with terrazzo floors include Neval? ÃÆ' â € ¡ori, GÃÆ'¶bekli Tepe, Jericho, and Kastros (Cyprus).
Maps Terrazzo
Production
Terrazzo craftsmen create walls, floors, terraces, and panels by exposing marble chips and other fine aggregates on the surface of finished concrete or epoxy-resins. Many preliminary work of a tertiary worker is similar to a cement maker. Marble-chips, terrazzo minute need three layers of material. First, masons or terrestrial workers build a high-level concrete foundation three to four inches deep. Once the form is removed from the foundation, the worker adds a one-inch layer of sandy concrete. Before this layer is installed, the terrestrial workers partially install metal strips in the concrete wherever there is a connection or discoloration on the terrazzo. For the last layer, terrazzo workers combine and place into each panel a mixture of fine marble chips that may be pigmented in color. While the mixture is still wet, workers throw additional marble chips of various colors onto each panel and roll up the weighted roller (100-125 lbs) above the entire surface.
In the 1970s, terrazzo-based polymers were introduced and called thin terrazzo sets. Initially a polyester resin and a vinyl ester are used as a binder resin. Currently, most of the terrazzo that is installed is epoxy terrazzo. The advantage of this material over a one minute terrazzo is a wider color choice, 1 / 4 inch to 3 / 8 inch mounting thickness, lighter weight, faster installation, non-impermeable solution, higher strength, and lower vulnerability to cracking. The disadvantage of terrazzo-based epoxy resins is that they can only be used for interior applications, not exterior. Epoxy-based terzazzo will lose its color and slightly exfoliate when used outdoors, while a cement based terrazzo will not. In addition to a mixture of marble aggregates, other aggregates have been used, such as mother of pearl and abalone skin. Recycled aggregates include: glass, porcelain, concrete, and metal. Shapes and medals can be made on the site by bending the divider strip, or off site by cutting the water-jet.
When the terrazzo was completely healed, the maids grinded it with a terrazzo grinder, which was rather like a floor polisher, only much heavier. The slight depression left by the mill is filled with suitable grout material and hand-trowel for smooth and uniform surfaces; then cleaned, polished, and sealed.
Types and Systems
Terrazzo installations include bound and unbound methods. The bonded system includes: underbed, monolithic, chemically bonded, and most recently, thin-set (epoxy-resin) method. The bonded terrazzo is applied over the sand mortar cement that is above the concrete slab. The cement-sand layer allows for variation in the finished concrete slab that sits on it. The monolithic terrazzo is applied directly on a very flat, high-quality concrete floor. The thin terrazzo does not require concrete floors. Conversely, a flexible membrane can be mounted so that cracks do not appear on the surface. Unbonded includes a sand cushioning method that uses wire boosters, insulation sheets, and dust sand that absorbs any movement of the concrete plate.
Relationship to Mosaic
Although terrazzo comes from a mosaic artform, it does not place individual pieces in a decorative pattern. Instead, small pieces thrown into the mortar base create a more uniform surface appearance. The decorative pattern is made by using a divider that creates a line between different colored terrazzo mixes.
Deterioration
Cracking is the most common form of failure and is usually caused by a structural system that supports terrazzo topping rather than the material itself. Contact with bases or acids may aggravate the binder agent used in the terrazzo. If most of the floor must be replaced due to cracks, first must be cut, after which the structural surface should be checked before trying to find a compatible replacement. Terrazzo replacements should get a sustainable look by having the same colored marble chips with the rest of the floor. There is a general terrazzo formula that can be obtained. Otherwise, a "bracketing" system can be used that tries to recreate the original formula by mixing and matching different chips.
See also
- Stone engineering
- Mosaic
- Polished concrete
- Portuguese sidewalks
References
Source of the article : Wikipedia
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