The oldest concrete buildings were created earlier than we would suppose. So in this case it is valued this famous ” yet the old Roman’s …”

Yes. The Roman’s used concrete in a quite ordinary way and very much {especially over empire]. It is true however, that the certain kinds of concrete wall had been using in Greece and even yet in Egypt, it was using sporadic and to say truly ” it was not it.’ Concrete became the concrete till during Roman’s. The natural conditions helped them in a certain measure, especially the volcanic area to the west from Naples, near today’s costal town Pozzuoli. There was possible to find fine powder [so called poculan}, which after melting with water got hard. This getting hard was made by the mutual chemical reaction between the powder and water. Roman’s valued especially two characters of concrete: the great hardness and great resistant against water. They used concrete this way, that created concrete mortar melted with small stones or fragments from bricks and they it trampled or poured into the planking if need was between outer and inner facial masonry, which formed as matter of fact ” planking” this way {so the same way how so called skvarobeton = slag – concrete have been used recently]. Roman’s used concrete especially for building of spaces, bridges and aqueducts: a lot of them have been standing till today.

As in many other branches of human activity, so in this case together with the end of Roman’s empire had been starting the thousand time of ” darkness”.

Englishman James Parker produced so-called Roman’s cement only in 1796. He was brought to it by the discovery of John Smeaton, who found that aluminum lime together with water create hard up mortar. In 1774 Sameon built a lighthouse in Eddystone along his discovery. This way building material was appeared again in new time, which was used in a common way once..

The first concrete bridge was built in Souillac in France in 1816. American ” are discovering” concrete over building of Erie Canal in 1825. They used cement produced from ” hydraulic lime”, which was found out in New York Madison and on other places of The USA.

At that time Europe had known so called Portland cement, which overcame all previous ones with its characters. Englishman Joseph Aspdin invented it. His practical using and spreading was obstructed with imperfect producing procedures first. Only before the end of 19th century the production could offer fair Portland cement even if his price was nearly three times higher than ” normal cement”.

In spite of the high hardness of Portland cement it could not fill all dreams of brave architects. It was from this reason, that when we are speaking about hardness at the concrete, we have on our mind the tenacity in a press. This had known ” old Roman yet” and they constructed their builds [for example the rolling vault]. If the concrete is exerted with a pull it doesn’t stand in it. But in these cases, where builders wanted the buildings became slender and ”airy” they could not make it without ” a pull”. After it came to the word so called prestresed concrete or ferroconcrete. Engineer Lambolt had his idea, to strengthened concrete with steel [not quite right iron] bars, patented in 1855, but the time of ferroconcrete started only with coming 20^th century, where August Perret started with the realization of his works of French modern. Already in 1903, during the realization of dwelling house in Paris, he created first ferroconcrete skeleton. The using of this skeleton got him possibility to reach a row of advantages in solving the disposition of house [with a nice view on Seina and Eiffel’s tower]. Two years later he constructed a building of floor’s garages, it was only from ferroconcrete and glass this time.

The thinking of using the ferroconcrete was genial. It puts two materials together, which are complemented one another by their mechanical and physical characters. While concrete controls the great force in a press [if itself steel bar was forced this way on a brace it would curve], the steel bar ensures enough great hardness during forcing in a pull [itself concrete can not be force on a pull practically]. At the same time both materials have the same thermal expandability.

The advantages of ferroconcrete were applied in engineering works quickly in the beginning of 20^th century. The construction of ferroconcrete bridges were spreading systematically, which were taking specific form and a new elegant style with the subtle profiles. Consequently the ferroconcrete was used also for constructions of great halls without the inner supports. The important work of engineer E. Freyssinet testifies to it and he realized huge hangars for airships on the airport in Orly at Paris in 1916 yet.

The Sport hall in Roma is famous from the buildings after The Second World War by P. L. Nervi and A. Vittelozzi from 1957 and especially controversial Utzonov building in Sydney, which became a symbol of town. From the buildings realized in our country we could name for example the famous and excellent realized in a projecting way Zdakovsky most[ bridge].