Aerated Concrete
In 1890, Hoffman received a patent (Prague), which is aerated by the method was based on CO2, created during the reaction of hydrochloric acid and sodium bicarbonate. With this technology, manufactured septal slabs gazogipsa. See Robert Bakish for more details and insights. The next patent for cellular concrete are issued only in 1916 in Holland. By using this technology in aerated concrete pore formation in the concrete used in addition of organic matter. However, due to negative effects of organic additives on concrete products technology has not received distribution.
Other methods for the formation of cellular structure and swelling lime-sand mass recommend the use of hypochlorite calcium and hydrogen peroxide. Raising the porous mass is due to oxygen evolution. Cellular concrete is also possible to create as a result of decomposition reaction of calcium carbide with water to produce acetylene. In 1918, Mr. Grosh (Berlin) for the first time suggested the use of powder made from metal for formation of gas in the manufacture of aerated concrete.
Metal powders can be zinc, magnesium, aluminum – aluminum became the most large distribution. It is widely known that between calcium hydroxide and aluminum chemical reaction occurs. In the course of this reaction in a considerable amount of hydrogen released, heat, and is the binding of water that has a positive effect on grasp and thickening porous concrete mixture. Porous mortar evenly interfere with aluminum powder, and then prepared solution is poured into pre-cooked form, and Only after this reaction occurs in solution with a large release of hydrogen. Formed during the reaction of hydrogen bubbles bloat aerated mixture and the latter is distributed around the bubbles, forming a homogeneous porous structure of the product. Here we should emphasize that for mixing porous mixture of aluminum powder to the desired uniformity is distinctive from the foam, where uniformity is possible only at very saturated solutions, it is possible to use solutions with less water. At the same strength and density porous skeleton between the bubbles of gas rising, and that ensures longevity and strength of aerated concrete products. Aerated concrete, popular in the world today, was patented in Sweden in 1922, the inventor of Erickson, who is considered the founder of the current cellular concrete used in construction industry. Only 16 years have been created out of reinforced gazoebtona, but they are first used in Scandinavian countries. But not all procedures have been implemented in practice, the manufacture of cellular concrete.