Why in the concrete adds eggs?

Humanity is building thousands of years, it should be noted, reached in this case a lot of height: That there is only the evolution of building materials from the ancient clay and wood to the aerated concrete, and TEPLOBLOK.

But how was built the ancient, if the cement in the modern sense of the word it was not until 1824, when Joseph Aspdin invented a mixture of Portland cement, which, together with river sand, gravel and water afforded concrete. Such concrete excellent resistance to compression and have the necessary strength characteristics.

But the idea is to add concrete iron beams came up with another Frenchman - Jean-Louis Lambeau only in 1850.

Prior to that time in Russia (and not only) as a binding element used eggs - more precisely, their yolks. Egg yolk tied with lime sand and a few days gained sufficient strength solution. Remember, as in Soviet times, often unsuccessfully tried to blow up the pre-revolutionary buildings of concrete, mixed with the egg yolk? Standing and today the building built in 15-19 centuries - the best proof of the effectiveness of the addition of egg yolk in the concrete.

It is noteworthy that the yolks were added to the solution of not only Russian architects. Construction of the bridge over the Vltava River in Prague imposed on local farmers duty to bring to the court of fresh eggs.

Sometimes, as a link to the solution was added lime, clay, and the river even manure and sand. However, not all areas of the river yl possessed bonding properties, and therefore the eggs fortified solution.