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The first reinforced concrete skyscraper in the world was built in 1902-03
in Cincinatti, Ohio. The 16-storey structure demonstrated for the first time the
safety and economy of reinforced concrete frames for high-rise construction,
and was a vital stimulus for using reinforced concrete in fireproof construction.
Concrete was chosen as the structural material chiefly for economics; it
offered the equivalent of steel frames in load bearing capacity and other
physical properties, yet was somewhat lower in cost. Engineers all over the
world watched with great interest as construction proceeded smoothly along its
16-storey route. Today this building is recognized by engineers as having
revolutionized the building industry.
Text E. Sand concrete
For many, many years nature has been destroying stone, changing it into
sand. Now man is learning to do the opposite: he is using sand and cement to
create materials which could compete with stone in strength and beauty.
At first the idea of making concrete by using sand was completely
rejected. It is common knowledge that concrete is made from gravel and
cement, while a mixture of sand and cement is considered useful only to bind
bricks. This idea has gripped the attention and minds of scientists and engineers
to such an extent that it is no easy task to cast doubt upon this universally
accepted truth.
“Sand” concrete is made by putting the matrix under vibration which
almost completely eliminates its weak points. Sand concrete has now become
almost twice as strong as ordinary concrete with a course aggregate, and much
cheaper as well. At present several varieties of sand concrete have been
developed.
1. Render it in Russian:
Gas concrete containing fly ash and blast furnace slag is often used as
structural. The method of substituting heavy aggregates by light ones is a rather
common practice today. There are several chemical reactions taking place
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