Definition of cementOn this website you will find one or more meanings in your language for the word or expression: cement. As well as definitions of Wikipedia pages and other Web pages related to the cement floor and, of course, synonym of cement with appropriate images related to the use of this expression.
1. Concept of cementCement is a conglomerate formed from a mixture of calcined and then ground limestone and clay that has the property of harden upon contact with water. Mixed with stone aggregates (gravel and sand) and water, creates a mixture, malleable and plastic that forge and hardens, acquiring stony consistency, called concrete (in Spain, part of South America and the Spanish Caribbean) or concrete (in Mexico and part of South America). Its use is very widespread in construction and civil engineering.
Pastes and mortars made with clay or Marl, gypsum and lime for masonry buildings were used from antiquity. It was in the ancient Greece when they began to use volcanic Tuff taken from the island of Santorini, the first natural cements. In the 1st century BC started to use the natural cement in ancient Rome, obtained in Pozzuoli, near Mount Vesuvius. The dome of the Pantheon is an example of this. In Century XVIII John Smeaton built the foundations of a lighthouse on the cliff of Eddystone, on the Cornwall coast, using a calcined lime mortar. The 19th century, Joseph Aspdin and James Parker patented Portland Cement, named for its dark greenish gray color similar to the Portland stone in 1824. Isaac Johnson, in 1845, obtain the prototype of modern cement, with a mixture of limestone and clay calcined at high temperature. In the 20th century comes the rise of the cement industry, due to the experiments of Vicat and Le Chatelier French chemists and the German Michaelis, who manage to homogeneous quality cement; the invention of the rotary kiln for calcination and tubular mill and the methods of transporting fresh concrete by Juergen Heinrich Magens that patents between 1903 and 1907.
Two basic types of cements can be:
1. of clay origin: obtained from clay and limestone in proportion 1 to 4.
2. of Pozzolanic origin: pozzolan cement may be organic or volcanic origin.
There are several different types of cement, by its composition, due to its properties of strength and durability, and therefore for their destinations and applications.
From the chemical point of view it is generally a mixture of silicates and calcium aluminates, obtained through the stew of limestone, clay and sand. The material obtained, ground finely, once mixed with water hydrates and gradually solidifies. Since the chemical composition of the cement is complex, specific terminologies are used to define the compositions.
2 Meaning of cementCement is a material that results from the combination of clay ground with chalk powder materials, insofar as possible, once they come into contact with the water solidifies and becomes hard. It is mostly used at the behest of the construction, just for that strength which, as adherent and Binder.
There are two types of cements, depending on the source that presents the same: clay source, made from clay and limestone; and on the other hand the Pozzolanic, containing pozzolana, a material aluminium silicon that they used in ancient Rome to produce cement until the appearance of cement portland in the 19th century. The aforementioned pozzolan can come from volcanoes or have an organic origin.
Therefore to cement it's considered as a given Binder material that is able to unite parts of various materials and give cohesion from different chemical change in mass.
Noteworthy is that when it is mixed with water, sand and gravel gets concrete or concrete, a mixture of malleable and uniform type which also features an extended in engineering and construction usage.
Its most notable properties include: chemical invasion and resistance to temperatures high among the most important.
Since ancient times it took special construction mixtures. In ancient Greece it was frequent the use of volcanic Tuff for the production of cement, i.e. more got it is only in a natural way, meanwhile, in the 19th century, precisely in the year 1824, was a revolution when the British Joseph Aspdin patented cement portland, named so by analogy, dark green coloration to the Portland stone.
Portland cement is a hydraulic cement that once mixed with water, steel fibres and aggregates becomes a mass of stone, solid features and it stands out because of its long duration. It is the star of the constructions to prepare the concrete.
3. Definition of cement
A material for livingThe history of cement is the story of man and his search for a space to live with maximum safety, protection and comfort. Since its inception and until today, technical advances have transformed this material into an indispensable element for social development and the improvement of the quality of life of the people.
Since the beginning of mankind, the evolution of the construction activity has been closely linked to the knowledge and the use of materials, originally in its natural state, and later in a more elaborate State. The first buildings were limited to simple walls and roofs, creating areas protected from the outside by means of the use of natural plant and mineral materials as unique elements of structures. Use of minerals with hydraulic characteristics - such as gypsum and lime known by the name of cements (from the latin cementum), thus achieving the union's primary elements was later made.
Cements have been used historically, at least 8,000 years, to:
-cement (cement + water)
-mortar (cement + water + sand)
-concrete (cement + water + sand + aggregates)
Portland cement - as we know it today - is a hydraulic Binder invented in the 18th century and obtained the joint grinding of portland clinker - product derived from the roasting at high temperatures of limestone - gypsum and certain additions.
The ages of the cement
Prehistory8,000 Years ago, the mix of cement with water, sand and aggregates resulted a new material that could be moledar easily and that, when it hardened, acquired characteristics of remarkable strength, resistance and durability. This new material was the origin of the concrete.
According to historical sources, the oldest building in concrete is the floor of a hut in Lepensky Vir (Yugoslavia), dating from 5,600 BC
Ancient ageThe Egyptian people had already used a mortar - mix sand with cementitious material - to join stone blocks and lift its prodigious buildings. Part of one of the pyramids of Giza (2600 BC) was built with concrete, and scenes of men manufacturing concrete and applying it in a work are preserved in the wall of Thebes (1,950 BC).
Greek and Roman builders discovered that certain materials from volcanic deposits, mixed with limestone, sand and water, produced a mortar of great strength, able to resist the action of the fresh and salt water. Roman civilization used the concrete in the construction of large buildings, and also in the drinking water supply and wastewater evacuation.
Among other Roman use of concrete examples, the following can be highlighted:
-The Amphitheatre of Pompeii, built in 75 B.c., shows rings of concrete on its perimeter.
-The Colosseum in Rome, built in A.d. 82, contains concrete in the foundations, the interior walls and structure.
-The Pantheon of Rome, built in the year 127 ad, where a lightweight concrete was used to build the dome, 50 m in diameter.
-In different pipes of water, with numerous examples.
Medieval concreteAfter the great role of concrete in structures of the Roman Empire, samples of its use are not up to the year 1200, in that it gets used for the construction of great works as the Salisbury Cathedral in England, whose foundations are made of concrete.
Portland cementFrom the mid-18th century, began to conduct a series of research related to the cement and concrete. Thus, 1.759, John Smeaton, an engineer from Leeds, in the United Kingdom, developed a new mortar to attach the stone blocks of the Eddystone Lighthouse. Few years later, the Reverend James Parker created a new cement accidentally burn some limestones. This new cement, called Roman cement because it was thought that it was that had been used in the Roman period, was patented and used in various works in the United Kingdom.
In 1824, James Parker and Joseph Aspdin patented a new artificial hydraulic cement, manufactured by the joint combustion of limestone and coal, called Portland Cement by its dark, color similar to the Isle of Portland stone. In the beginning this material was not too employee, because of its complex manufacturing process, that affected his production.
Towards the end of the 19th century, the process of industrialization and the introduction of rotary kilns led to the extension of its use for all applications. Currently, and in spite of all the introduced technical improvements, the Portland cement continues to be, in essence, very similar to the first one that is patented, although its impact and benefits have improved very significantly.