Technical Supports
Travertine Utilization
Date:11/25/2006 Read:528
Travertine are particular carbonate rocks, easily distinguished from other limestone for their different appearance: in fact, they have a very compact paste made up of grains so fine they are invisible to the naked eye and feature vacuoles, natural holes that typify the surface, known in sector jargon as taroli and sometimes entirely covered with tiny crystals. This aspect is quite visible if the material is cut al contro (as is generally the case with travertine), with the vacuoles riddling the surface and only sometimes showing the Barcelona. The Sant Jordi sports arena, seating 17,000, designed by A. Isozaki, with a dark, symmetrical roof and travertine-clad entrance S4 stratified or zoned structure of the material, often visible only under close observation. Even in the cut verso (with the grain) the vacuoles are visible, but less. evident: the material reveals the circular and nearly circular shapes typical of concretion, in some varieties quite evident and in others merely hinted at. The vacuolar nature of travertine is a typical characteristic, although in reality not all travertine have cavities, at least not in an evident fashion. Travertine are often used filled-in, and in this case it is the particular non-crystalline, sometimes porous, look of the material that distinguishes it. In addition, the material always reveals concretion motifs, most often in the form of small spheroid shapes and frequently along the stratification planes which, unlike those in normal sedimentary rocks, are not linear but very wavy, variegated, thanks also to these little round forms that give further motion to the pattern. The particular appearance of travertines that differentiates them from other limestones - and commercially sets them into a class by themselves - is due to their different origin; in fact, these are concretion rocks, similar to alabasters and stalactites, while the other carbonate rocks are generally marine in origin. This means that travertines were formed mostly near the surface, while rocks in general were formed at great depths, often subjected to pressures and tectonic thrusts that provoked phenomena of re crystallization and rock hardening. Furthermore, travertines are geologically recent rocks (formed in the same geological age in which we live, the Quaternary: for example, the average age of Roman travertine is estimated at only 100,000 years, while the most common compact limestones are hundreds of millions of years old (Mesozoic era). The color of travertine varies quite a bit: generally it is pale beige tending to white (such as historical Roman travertines) but can be completely white, like most of the travertine used in modern architecture, which is installed unpolished and gives buildings a suggestive appearance thanks to its warm white color, very different from the cold white typical of polished marbles. In any case, travertines can also have darker, brownish tints, such as walnut travertine. Finally, there are also highly colored travertines, such as the reds and yellows from Iran: their pigmentation gives the material a very bright, dense hue devoid of any transparency. In fact, yellow travertine is reminiscent of the most colorful varieties of yellow Verona marbles, whose shades are particularly intense. However, even the pale travertines, including the white ones, can be made interesting from a chromatic standpoint by means of filling them in, which enhances their appearance while protecting them from water and the accumulation of dust. They are generally filled in with stucco in the same tint as the stone, but sometimes with pastes in contrasting colors, such as red, that stand out from the rock. This gives the material a very different look and to the inattentive observer the fills may not appear as such but seem to be special structural motifs or even fossils. Travertines have excellent physical-mechanical properties and are also very hard, to the point that Piericonsiders them second in hardness only to granites and beo/as. Which might seem strange when you realize that, newly extracted, travertine has physical characteristics still in a phase of change. In fact, in contact with air a block of travertine continues to harden and become more compact, due to an ongoing transformation of calcium bicarbonate into calcium carbonate. Moreover, even the color of travertine tends to change after extraction: for example, the paler varieties tend to yellow due to oxidation of its ferrous salts. Thanks to its excellent compression resistance travertine has always been used for structural purposes, to construct entire buildings: examples are the major Roman monuments and the city''s myriad churches, St. Peter''s Basilica for instance. On the other hand, travertine wears badly and so is inadvisable for large-scale paving. Nowadays travertines are used not only for structural works or cladding but, since they can be polished, are also marketed as ornamental slabs, although not premium and for routine use; before they are polished, vacuolar travertines are generally filled in. Red and yellow travertines are, on the other hand, used to create very decorative effects and are often installed unpolished to confer a rustic aged appearance. They are among the materials most commonly given an aging treatment to create particular decorations, often for flooring, which are currently quite in vogue. Travertines generally have a very affordable price, even the colored ones, which cost just a bit more. Italy is a region especially rich in travertines , especially in Lazio, Tuscany and the Marches. The best-known Italian travertines on the market are the Roman (meaning those from Tivoli, Latina, Guidonia, Fondi and other nearby areas) in the numerous varieties (classic, Navona, golden, walnut, etc.) and the Tuscan and Ascoli, both marketed in many varieties; also well known are the aforementioned red and yellow travertines from Iran. [size=4]文字[/size]
Date:11/25/2006 Read:528
Travertine are particular carbonate rocks, easily distinguished from other limestone for their different appearance: in fact, they have a very compact paste made up of grains so fine they are invisible to the naked eye and feature vacuoles, natural holes that typify the surface, known in sector jargon as taroli and sometimes entirely covered with tiny crystals. This aspect is quite visible if the material is cut al contro (as is generally the case with travertine), with the vacuoles riddling the surface and only sometimes showing the Barcelona. The Sant Jordi sports arena, seating 17,000, designed by A. Isozaki, with a dark, symmetrical roof and travertine-clad entrance S4 stratified or zoned structure of the material, often visible only under close observation. Even in the cut verso (with the grain) the vacuoles are visible, but less. evident: the material reveals the circular and nearly circular shapes typical of concretion, in some varieties quite evident and in others merely hinted at. The vacuolar nature of travertine is a typical characteristic, although in reality not all travertine have cavities, at least not in an evident fashion. Travertine are often used filled-in, and in this case it is the particular non-crystalline, sometimes porous, look of the material that distinguishes it. In addition, the material always reveals concretion motifs, most often in the form of small spheroid shapes and frequently along the stratification planes which, unlike those in normal sedimentary rocks, are not linear but very wavy, variegated, thanks also to these little round forms that give further motion to the pattern. The particular appearance of travertines that differentiates them from other limestones - and commercially sets them into a class by themselves - is due to their different origin; in fact, these are concretion rocks, similar to alabasters and stalactites, while the other carbonate rocks are generally marine in origin. This means that travertines were formed mostly near the surface, while rocks in general were formed at great depths, often subjected to pressures and tectonic thrusts that provoked phenomena of re crystallization and rock hardening. Furthermore, travertines are geologically recent rocks (formed in the same geological age in which we live, the Quaternary: for example, the average age of Roman travertine is estimated at only 100,000 years, while the most common compact limestones are hundreds of millions of years old (Mesozoic era). The color of travertine varies quite a bit: generally it is pale beige tending to white (such as historical Roman travertines) but can be completely white, like most of the travertine used in modern architecture, which is installed unpolished and gives buildings a suggestive appearance thanks to its warm white color, very different from the cold white typical of polished marbles. In any case, travertines can also have darker, brownish tints, such as walnut travertine. Finally, there are also highly colored travertines, such as the reds and yellows from Iran: their pigmentation gives the material a very bright, dense hue devoid of any transparency. In fact, yellow travertine is reminiscent of the most colorful varieties of yellow Verona marbles, whose shades are particularly intense. However, even the pale travertines, including the white ones, can be made interesting from a chromatic standpoint by means of filling them in, which enhances their appearance while protecting them from water and the accumulation of dust. They are generally filled in with stucco in the same tint as the stone, but sometimes with pastes in contrasting colors, such as red, that stand out from the rock. This gives the material a very different look and to the inattentive observer the fills may not appear as such but seem to be special structural motifs or even fossils. Travertines have excellent physical-mechanical properties and are also very hard, to the point that Piericonsiders them second in hardness only to granites and beo/as. Which might seem strange when you realize that, newly extracted, travertine has physical characteristics still in a phase of change. In fact, in contact with air a block of travertine continues to harden and become more compact, due to an ongoing transformation of calcium bicarbonate into calcium carbonate. Moreover, even the color of travertine tends to change after extraction: for example, the paler varieties tend to yellow due to oxidation of its ferrous salts. Thanks to its excellent compression resistance travertine has always been used for structural purposes, to construct entire buildings: examples are the major Roman monuments and the city''s myriad churches, St. Peter''s Basilica for instance. On the other hand, travertine wears badly and so is inadvisable for large-scale paving. Nowadays travertines are used not only for structural works or cladding but, since they can be polished, are also marketed as ornamental slabs, although not premium and for routine use; before they are polished, vacuolar travertines are generally filled in. Red and yellow travertines are, on the other hand, used to create very decorative effects and are often installed unpolished to confer a rustic aged appearance. They are among the materials most commonly given an aging treatment to create particular decorations, often for flooring, which are currently quite in vogue. Travertines generally have a very affordable price, even the colored ones, which cost just a bit more. Italy is a region especially rich in travertines , especially in Lazio, Tuscany and the Marches. The best-known Italian travertines on the market are the Roman (meaning those from Tivoli, Latina, Guidonia, Fondi and other nearby areas) in the numerous varieties (classic, Navona, golden, walnut, etc.) and the Tuscan and Ascoli, both marketed in many varieties; also well known are the aforementioned red and yellow travertines from Iran. [size=4]文字[/size]
