What is Pozzolana?
Pozzolana is a volcanic ash that is used as a mixture in cement to ensure strength and resistance to wear and chemical disintegration. It is named around the city where it was first discovered, Pozzuoli in the Ital Region of Campania. It was used in ancient Roman times, like the way it is used today. Some structures created by IT lasted more than 2,000 years.
Originally, the back -up ash was mixed with the lime to form a strong cement mixture. The first structures, which are known to be built with a background, were created somewhere around the 3rd century B.C. In addition to being strong and robust, structures created with cement were able to construct underwater due to the fact that the cement could set or harden while still submerged.
The original pozzolana was made purely from the ash of volcanoes, but today is often made of synthetic material such as fly ash, micro-silica or metacaolin. These modern incarnations are referred toas puzzlanic materials. Regardless of their origin, the back -up materials contain some type of material, usually silica or aluminum oxide, in reactive form; When they are in the presence of water, finely divided forms of materials form cement pozzzolana when they react with calcium hydroxide.
In modern times, the cements of Pozzolana are usually a mixture of natural and synthetic background in combination with Portland cement, which is a mixture of concrete, mortar, stucco and grout and the most common cement. The resulting cement mixture is very resistant to water and also the most common forms of corrosion. In addition to being strongly resistant to water, it has many modern cements of pozzolan magnetic properties that further increase the strength of cement.
Although a number of modern puzolanic materials are used, the most common is ash. This is a finely divided rest usually made of burning of drunk coal or lignite. Ashis collected from different types of power plants and industrial plants. In addition to being cheaper than Portland cement, the use of ashes can improve the production time because it is easier to produce than pure cement.
As evidence of the durability of Pozzzolan, it is only necessary to look at the structures built with him, which still stands. These include the Pantheon and the Colosseum in Rome as well as the aqueducts that pass through the city. The Roman port in Cosa was also built from Pozzolany about 2,000 years ago, and the three -built underwater mols are still visible and in excellent condition since 2012.