מתוך socialsciences

קפיצה אל: ניווט, חיפוש

Concrete is often a composite construction substance composed principally of aggregate, cement and water. You'll find several formulations which have diverse properties. The aggregate is usually a coarse gravel or crushed rocks these as limestone, or granite, in addition to a wonderful aggregate these as sand. The cement, frequently Portland cement, and also other cementitious resources such as fly ash and slag cement, serve as being a binder for your aggregate. Various chemical admixtures may also be additional to achieve different properties. Water is then mixed with this dry composite which enables it to become formed (ordinarily poured) and after that solidified and hardened into rock-hard energy through a chemical course of action often known as hydration. The h2o reacts with all the cement which bonds one other elements jointly, sooner or later developing a robust stone-like stuff. Concrete has reasonably high compressive energy, but much reduce tensile strength. For that reason is often strengthened with supplies which might be solid in stress (often metal). Concrete can be damaged by numerous processes, such because freezing of trapped water.

Concrete is widely useful for building architectural structures, foundations, brick/block partitions, pavements, bridges/overpasses, motorways/roads, runways, parking structures, dams, pools/reservoirs, pipes, footings for gates, fences and poles and even boats. Famous concrete structures incorporate the Burj Khalifa (world's tallest making), the Hoover Dam, the Panama Canal plus the Roman Pantheon.

Concrete technological innovation was identified from the Ancient Romans and was broadly utilized inside the Roman Empire. After the Empire handed, usage of concrete became scarce right until the technologies was re-pioneered in the mid-18th century.

The environmental impact of concrete is usually a sophisticated mixture of not entirely unfavorable consequences; even though concrete is actually a significant contributor to greenhouse gasoline emissions, recycling of concrete is progressively prevalent in structures that have reached the stop in their living. Structures made of concrete may have a lengthy support existence. As concrete has a substantial thermal mass and very lower permeability, it may possibly make for electricity effective housing.

Historical past

The phrase concrete arises from the Latin word "concretus" (indicating compact or condensed), the proper passive participle of "concrescere", from "con-" (collectively) and "crescere" (to mature).

Concrete was useful for building in lots of ancient structures.

During the Roman Empire, Roman concrete (or opus caementicium) was comprised of quicklime, pozzolana and an aggregate of pumice. Its prevalent use in lots of Roman structures, a essential occasion from the history of architecture termed the Roman Architectural Revolution, freed Roman design in the limits of stone and brick stuff and permitted for innovative new patterns with regards to both equally structural complexity and dimension. Hadrian's Pantheon in Rome can be an illustration of Roman concrete construction.

   Concrete, for the reason that Romans knew it, was a new and innovative material. Laid from the form of arches, vaults and domes, it rapidly hardened into a rigid mass, absolutely free from many  in the inner thrusts and strains that troubled the 

builders of comparable structures in stone or brick.

Modern-day exams demonstrate that opus caementicium had as significantly compressive energy as contemporary Portland-cement concrete (ca. 200 kg/cm2). Nonetheless, a result of the absence of steel reinforcement, its tensile power was far lessen and its mode of application was also diverse:

   Modern structural concrete differs from Roman concrete in two important information. To begin with, its  blend consistency is fluid and homogeneous, allowing it being poured into forms alternatively than requiring hand-layering together with the placement 

of aggregate, which, in Roman apply, frequently consisted of rubble. 2nd, integral reinforcing metal gives present day concrete assemblies good power in pressure, whereas Roman concrete could rely only upon the power on the concrete bonding to resist stress.

The widespread utilization of concrete in many Roman structures has ensured that lots of survive towards the current day. The Baths of Caracalla in Rome are merely one case in point. Quite a few Roman aqueducts and bridges have masonry cladding on a concrete core, as does the dome with the Pantheon.

Some have stated the magic formula of concrete was misplaced for thirteen centuries until finally 1756, when the British engineer John Smeaton pioneered the usage of hydraulic lime in concrete, employing pebbles and powdered brick as aggregate. Nonetheless, the Canal du Midi was constructed utilizing concrete in 1670. Furthermore you can find concrete structures in Finland that day again on the 16th century.[citation needed] Portland cement was to begin with utilised in concrete during the early 1840s.


Concrete additives are actually utilized since Roman and Egyptian moments, when it absolutely was found out that adding volcanic ash to your blend permitted it to set underneath water. Similarly, the Romans knew that including horse hair created concrete considerably less liable to crack although it hardened and including blood created it a lot more frost-resistant.

In modern day periods, researchers have experimented along with the addition of other supplies to generate concrete with improved homes, this sort of as higher strength or electrical conductivity.


You will find lots of forms of concrete offered, developed by varying the proportions on the primary elements down below. In this way or by substitution for that cemetitious and aggregate phases, the completed solution can be tailored to its application with various energy, density, or chemical and thermal resistance qualities.

Recently using recycled supplies as concrete ingredients has long been gaining reputation as a result of increasingly stringent environmental laws. Essentially the most conspicuous of these is fly ash, a by-product of coal- fired strength plants. This use lowers the amount of quarrying and landfill room demanded as the ash functions as being a cement replacement so lowering the amount of cement required.

The mix style depends around the type of construction staying designed, how the concrete will probably be combined and delivered and the way it's going to be put to form this composition.

Ready-mixed concrete share is continually rising from the construction of concrete output and utilizing. In European Union the share of ready-mixed concrete reached ninety three.39% in 2010.

More info on concrete at Champaign IL Decorative Concrete and Decorative Concrete Decatur Illinois Article by fox and austin concrete

כלים אישיים