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jeudi 16 octobre 2014

Abcs Of Concrete Color Pigment

By Estelle Larsen


The invention of reinforced concrete is often attributed to builder William Wilkinson, who asked in 1854 a patent for a system that included iron armor for 'improving housing construction, warehouses and other fire-resistant buildings. Sydney Opera House, a building designed by Danish architect Jorn Utzon in 1957 and opened in 1973, in Sydney, Australia used concrete color pigment.

Embedding the rebar (ie steel bars) increases the tensile strength significantly. It is called reinforced slabs. This characteristic is used, inter alia, in beams, as they break easily without reinforcement. With reinforcement beam power is increased considerably. The slabs are an old invention. In Ancient Greece and the Etruscans produced a material similar to it. It was used for buildings such as houses, aqueducts and bridges. And a large part of them still exist, including Pantheon's dome, spanning 45 meters.

There are no signs of its use found until the thirteenth century, when it was reused in the foundation of Salisbury Cathedral and the famous Tower of London, England. During the Renaissance, its use was low and not significant. In some cities, large structures built by Mayans and Aztecs in Mexico or Machu Pichu in Peru used cement.

There are some studies which suggest that during the construction of the Great Pyramid of there was production of artificial sandstone - a form of concrete-material. Previously deposited debris of demolished structures was also used. Today crushed waste is increasing, so it can be reused as a base for new roads. Along with crushed asphalt included in recycling stable.

Concretes by their stone characteristics withstand compression forces, and other types of cracking stress (bending, tension, torsion, shearing); inclusion of metal rods optimize their characteristics and their widespread use in many engineering and architecture projects. The world's tallest buildings have steel structures, such as the Petronas Towers in Kuala Lumpur, Malaysia (452 meters, 1998), the Taipei 101 in Taiwan (509 meters, 2004), or the Burj Dubai city of Dubai (818 meters, 2009), in the XXI century.

The hemispherical dome, which is 43.44 m in diameter has resisted reforms for nineteen centuries without reinforcements. The bulk murario ring is brick and tile works (concrete bricks) and dome lightened using pumice as aggregate. In ancient Greece, around 500 BC. C., they mixed compounds calcined limestone with water and sand, adding crushed stones, broken tiles or bricks, creating the first concretes history, using tuff taken from the island of Santorini.

Since one of the harmful effects to the environment is that cement production generates large volumes of carbon dioxide, the cement replacement technology plays an important role in efforts to reduce emissions of carbon dioxide. It is typically included in certain catalysts which allow its 'autolavado' such as titanium dioxide mixtures. It is also used to confine radioactive waste.

And there is a variety of them: colorants, accelerators, retarders, flow, sealants, fibers, etc. Conventional concretes normally used in pavements, buildings and other structures have a specific gravity (density, volumetric weight, unit weight) ranging from 2200-2400 kg / cubic meters (137-150 lb / ft 3). The density of concrete varies depending on the quantity and density of aggregates, the amount of trapped air (occluded) or intentionally included and the amounts of water and cement.




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