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Sunday 22 June 2014

Concrete

The ancient Romans had concrete at least as early as 200 BC making it with pozzolana, a volcanic ash from Mount Vesuvius, near Pozzuoli, Italy. Pozzolana is still used today.

Pozzolana concrete was at first used it only for terrace walls and foundations, as, for example, at the Temple of Fortuna Primigenia at Palestrina, erected about 80 BC.

It was the emperor Nero who first used the material on a grand scale to rebuild a region of the city of Rome around his palace, the expansive Domus Aurea (Golden House), after the great fire of AD 64.

Roman concrete was a fluid mixture of lime and small stones poured into the hollow centers of walls faced with brick or stone and over curved wooden molds, or forms, to span spaces as vaults.

The development of concrete used in conjunction with brick, along with a great deal of engineering skill, allowed the construction of buildings such as the Pantheon, (100-125), and the Coliseum.(72-80).

The Romans also used concrete for aqueducts, bridges and domes..

The Pantheon in Rome, built in 120 AD, is still the largest reinforced concrete dome in the world. With no metal skeleton, it fails current health and safety legislation.

Although the Romans used plenty of concrete, after the fall of the Empire the technology fell out of practical human knowledge for over 700 years.

Concrete was little used until 1752 when John Smeaton, an English engineer, rediscovered how to make waterproof cement and used it as mortar for a stone lighthouse at Eddystone, England.

Filipino churches built during Spain's colonial period used millions of egg whites in the concrete to make it more durable.

By 1900 concrete had taken the place of a great deal of masonry and wood.


Just over 5 million barrels of concrete were required to build the Hoover Dam on the border of Arizona and Nevada. Even though it was built between 1931 and 1936, that concrete is not expected to completely set till at least 2035.

On January 7, 2019, 32,315.5 m³ (1,141,211.1 ft³)  of concrete was poured at the site of Polavaram Dam Project, in Polavaram, Andhra Pradesh, India. It set two Guinness World Records, one for Largest Continuous Concrete Pour and one for Most Concrete Continuously Poured in 24 Hours. Navayuga Engineering Company Limited's record attempt took place at the spill channel of the Polavaram Dam Project site which aims to provide irrigation and electricity to the region.


The concrete used by the Roman Empire has been proposed as an alternative to modern concrete. It's believed that it would have a substantially smaller environmental impact than our own in addition to being far more durable, surviving thousands of years in harsh conditions nearly unscathed.

NASA developed a form of concrete that doesn't need water, to be used as a construction material on the Moon.

The world record for the fastest time to break 16 concrete blocks on the body is 4.75 seconds, achieved by Ali Bahçetepe from Turkey in Milas Cumhuriyet Square, Muğla, Turkey, on March 18, 2017. Ali Bahçetepe broke his previous record of 6.33 seconds recorded exactly three years earlier.



China consumed 6.6 gigatons of concrete between 2011 and 2013, That’s more than the US used in the entire 20th century.

Concrete is the second-most-used substance on earth after water.

The weight of the world’s tallest building, Dubai’s Burj Khalifa, is 440,000 tons. It is the equivalent to about 100,000 elephants.

Source Compton's Interactive Encyclopedia © 1998 The Learning Company, Inc.

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