The material from which the Roman Colosseum was completely built is called travertine. What it is? Let's figure it out.
Travertine - what is it?
Lime tufa is called travertine - a polycrystalline fine-grained rock. The name of the stone comes from the Italian travertino. In the first century BC, the material was called a stone from Tibur (lapis tiburtinus). Travertine is an intermediate form of stone between limestone and marble.
How is formed
Travertine is a product of the precipitation of calcium carbonate (aragonite or calcite) from cold or hot carbon dioxide sources. The rock is formed by removing carbon dioxide solutions from soluble calcium bicarbonate:
Ca (HCO 3 ) 2 → CaCO 3 + H 2 O + CO 2 .
The main reason for this is the pressure drop that can occur when groundwater emerges to the surface, with diffusion into the atmosphere associated with intense water movement, and also with assimilation by plants. Travertine stone often contains prints of plants. It may also contain various organic residues.
Natural travertine: basic characteristics
The stone is characterized by a porous structure, which distinguishes it from limestone, which is a dense material. The porosity of the material ranges from 2 to 40%. The cells in the structure of travertine are formed due to bubbles of sulfur dioxide rising upward and passing through the calcareous layers. You can see the round holes remaining from the outlet of sulfur dioxide by making a cut parallel to the direction of sediment formation.
Travertine is a stone with a low hardness (easily cut with a circular saw). Its density is an average of 1400-1800 kg per cubic meter. meter.
What colors is travertine?
Travertine is characterized by light colors of different shades. The breed can be white, yellowish, grayish, cream, etc. Due to the presence of iron salts in the travertine, it can change color as a result of their oxidation. For example, a white stone can acquire a sand or yellow tint. This does not affect the material properties.
Stone is also found in darker shades (brownish, brownish-gray, etc.). Travertines with a darker color are characterized by the best technical qualities.
There are also stones with intense coloring. An example of such material is yellow and red travertine in Iran. What it is? This is calcareous tuff containing certain pigments that give it a very bright shade.
Factors Affecting Travertine Properties
The properties of the resulting material depend on many factors - the content of dissolved carbon dioxide, flow turbulence, temperature indicators, etc.
Solid quality travertine forms in stagnant water. In places characterized by a strong current (for example, at waterfalls), as a rule, jelly travertine is obtained. What it is? Unevenly colored, with large, tufa calcareous pores grouped into groups.
The greater the number of impurities of biological origin will be involved in the formation of the rock, the higher will be its porosity.
The density of travertine depends on the pressure of the overlying layers on the lower, as well as the intensity of the new deposition of calcium carbonate on the layers that were previously formed. Sometimes it turns out that the upper layer of sediments can pass a new sediment through itself, due to which the pores and voids formed in the rock are filled. The result of this is a solid and very strong material.
The color of travertine largely depends on whether calcium carbonate was subjected to additional external influences during the deposition process. If not, it will be white (or as close to white as possible), which rarely happens. The main part of travertines due to the presence of particles of sand, silt, plant residues is characterized by shades ranging from light beige to walnut. When a layer of white travertine is contaminated by particles of river origin, it can also acquire a gray color.
Some materials include brown blotches or layers of clay origin. This is due to the fact that the formation of travertine occurred in different periods, that is, the sources did not always go out equally to the ground, their course changed.
Where are travertine deposits located?
The most famous travertine deposits are located in Italy (Tivoli, located near Rome), Germany (near Stuttgart), Turkey (the city-museum of Pamukkale, classified as a UNESCO World Heritage Site).
The largest deposits in the territory of the former USSR are in Azerbaijan and Armenia. So, the Ararat region is famous for its mines, which are one of the largest in the world. Travertine lying there is characterized by a high degree of crystallization, and therefore, high strength.
In Russia, deposits of calcareous tuff are located in the Pyatigorsk region and in Kamchatka.
Also travertine deposits are available in Tajikistan, Ukraine, Kyrgyzstan.
Where is travertine used? Main applications
Lime tufa is highly durable and can be processed well, which is why it is successfully used as a building and facing stone. Since ancient times, houses, bridges, amphitheaters and other buildings were built from it. The most famous and largest building is the Colosseum, which was completely built from light yellow Roman travertine (from the Sabini mountains).
The stone is also used for the production of building materials and the fight against high soil acidity in agriculture.
But the most widely used today travertine is used as a decorative material for interior decoration both inside and outside.
Travertine as a decoration material
Travertine, the price of which is relatively low (from 5000 rubles / m 2 ), due to its qualities, allows it to produce various types of decoration materials for decoration, which differ in a number of advantages. The main among them are environmental friendliness, durability, frost resistance and moisture resistance.
Most often, travertine is used in a cut version in the form of tiles that differ in a nosy surface and stacked according to the mosaic principle. Due to its strength, the material can be used both for wall decoration and for covering terraces or floors. Tuff flooring is abrasion resistant. Caring for them is similar to caring for marble material.
Also travertine is used for the manufacture of countertops, window sills, stairs, bar counters and a number of other interior elements.
The porous structure of the material allows you to fill its cells with a special solution, thanks to which the attractiveness of travertine is preserved. Some varieties of this breed have an external resemblance to a tree, due to which they combine quite well with some other materials and furniture.
Travertine is widely used to create an interior in the antique style. In this case, its surface is treated in order to increase the porosity and randomness of the spread of cells.
Along with a natural mineral, its imitation - artificial travertine - has become widespread. This material is similar in color and texture, however, differs in composition and some properties.
Due to the fact that cement is used in the production, artificial travertine lining is much more resistant to aggressive environments.