WORLD CHANGERS

 Hello ladies and gents this is the Viking telling you that today we are talking about

Concrete

• Concrete is one of the most widely used man-made material. It's a composite material composed of rough composite bonded together with a fluid cement which hardens over time.
• Most concretes used are lime-based, asphalt concrete, and polymer concretes. Earlier, Limestone was used as a crude cement. As the materials and combinations improved, modern concrete was invented.
• One of the key ingredients of concrete is cement. The foundation to cement was laid in 1300 BC.
• Middle eastern builders coated the outside of their clay fortresses with a thin, and moist burned limestone, which chemically reacted with gasses in the air to form a hard, protective surface.
• Around 6500 BC, the first concrete-like structures were built by the Nabataea traders or Bedouins in the southern Syria and northern Jordan regions.
• By 700 BC, the significance of hydraulic lime was known, which led to the development of mortar supply kilns for the construction of rubble-wall houses, concrete floors, and underground waterproof cisterns.
• By 3000 BC, the Egyptians were using early forms of concrete to build pyramids.
• In 1824, the most used Portland cement was invented by Joseph Aspdin of England. George Bartholomew had laid down the first concrete street in the US during 1891, which still exists.
• By the end of the 19th century, the use of steel-reinforced concrete was developed. In 1902, using steel- reinforced concrete, August Perret designed and built an apartment building in Paris. This building a wide admiration and popularity to concrete and also influenced the development of reinforced concrete
• In 1921, Eugène Freyssinet pioneered the use of reinforced- concrete construction by building two colossal parabolic-arched airship hangars at Orly Airport in Paris.

And as always have a chilled day from the Viking