Concrete

Concrete

Concrete is a manufactured mixture of cement and water, with aggregates of sand and stones, which hardens rapidly by chemical combination to a stonelike, water-and-fire-resisting solid of great compressive but low tensile strength. Reinforced concrete was developed to add the tensile strength of steel to the compressive strength of mass concrete, the metal is embedded by being set as a mesh into the forms before pouring, and in the hardened material the two act uniformly. Doing the concrete be inexpensive.

Three 20th-century developments are:

** __Concrete-shell construction__ ** : permits the erection of vast vaults and domes with a concrete and steel content so reduced that the thickness is comparatively less than that of an eggshell.


 * __Precast-concrete construction__ **: employs bricks, slabs, and supports made under optimal factory conditions to increase waterproofing and solidity, to decrease time and cost in erection, and to reduce expansion and contractions.
 * __Prestressed concrete__** : provides bearing members into which reinforcement is set under tension to produce a live force to resist a particular load. Since the member acts like a spring, it can carry a greater load than an unstressed member of the same size.





Kresge Auditorium, MIT campus
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__**What is the difference between tiltwall construction, tilt-up panel construction and pre-cast concrete construction? **__

Tilt-up and tiltwall are two terms used to describe the same precast concrete process. The innovative method of construction til-up is used in the outside of the constuctions. Don't exist limitations about the size of the structrures and is more flexibility,but with this process the weather can be a problem, while the tiltwall are made in a manufacturing and later are transported till the construction increasing the cost.

