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.



**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.

** 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. The combination is much more versatile than either product; it serves not only for constructing rigid frames but also for foundations, columns, walls, floors, and a limitless variety of coverings, and it does not require the addition of other structural materials.

** Precast Concrete, Tilt-up Construction and Tiltwall: What's the Difference in These Terms? **

Tilt-up and tiltwall are two terms used to describe the same process. For a tilt-up concrete building, the walls are created by assembling forms and pouring large slabs of concrete called panels directly at the job site. this process does not require transportation and the size of the panels is limited only by the needs of the building and the strength of the concrete panels themselves. This panels can also be very wide and high so the architects have great flexibility to plan and create their buildings. The disadvantage of this technique is that the panels bedischarged outdoors, contractors are at the mercy of the weather, which can make construction schedules more difficult to meet.

The precast concrete building process is similar to tilt-up construction, but it addresses the challenges presented by weather.For precast concrete buildings, work crews do not set up forms at the job site to create the panels. Instead, workers pre cast concrete panels at a large manufacturing facility. Because the precast concrete forms are poured indoors, this activity can take place regardless the weather conditions. The disadvantage of this process is that the walls need to be transported, sometimes over long distances, and this imposes a limitation in height and width of the walls.

**Glossary **


 * Cement: a powdery substance made by calcining lime and clay, used in making mortar and concrete.
 * Coatings: a thin layer or covering of something
 * Concrete: a building material made from a mixture of gravel, sand, cement, and water, forming a stone-like mass on hardening.
 * Deck: A platform extending horizontally from one side of a ship to the other.
 * Domes: a rounded vault forming the roof of a building or structure.
 * Frame: a rigid structure surrounding a picture, door, etc.
 * Foundations: the lowest load-bearing part of a building, typically below ground level
 * Hardens: make or become hard or harder.
 * Hardscape construction: Hardscape, or "hardscaping," consists of the inanimate elements of landscaping, especially any masonry work or woodwork.
 * Mesh: material made of a network of wire or thread.
 * Pipes: a tube used to convey water, gas, oil, or other fluids.
 * Pouring: flow or cause to flow in a steady stream.
 * Pozzolan: type of volcanic ash used for mortar or for cement that sets under water.
 * Slabs: a large, thick, flat piece of stone or concrete.
 * Spring: An elastic device, such as a coil of wire that regains its original shape after being compressed or extended.
 * Stresses: To subject to mechanical pressure or force.
 * Tension: a strained state or condition resulting from forces acting in opposition to each other.
 * Traction: the action of pulling a thing along a surface.
 * Vaults: a roof in the form of an arch or a series of arches, typical of churches and other large, formal buildings.
 * Waterproofing: Impervious to water