What is the meaning of Tobermorite?
Tobermorite is a calcium silicate hydrate mineral with chemical formula: Ca5Si6O16(OH)2·4H2O or Ca5Si6(O,OH)18·5H2O. Tobermorite occurs in hydrated cement paste and can be found in nature as alteration mineral in metamorphosed limestone and in skarn.
What is aluminous Tobermorite?
An international group of scientists recently found that the key to the strength of ancient Roman concrete is the presence of aluminous tobermorite, a mineral that slowly forms within voids and prevents cracks from traversing through the concrete.
How is tobermorite formed?
Tobermorite is a mineral, which, thanks to its composition and properties, is an important phase in aerated concrete and it can be also used as an ion exchanger. Tobermorite crystallizes together with other calcium silicate hydrates from the system CaO–SiO2–H2O during hydrothermal reactions.
What is the density of Muscovite?
| Muscovite | |
|---|---|
| Specific gravity | 2.76 – 3 |
| Density | 2.83 g/cm3 |
| Melting point | approximately 1320°C |
| Diaphaneity | transparent or translucent |
Did the Romans have concrete?
The Romans made concrete by mixing lime and volcanic rock. For underwater structures, lime and volcanic ash were mixed to form mortar, and this mortar and volcanic tuff were packed into wooden forms.
How is Ettringite formed?
Gypsum and other sulfate compounds react with calcium aluminate in the cement to form ettringite within the first few hours after mixing with water. Most of the sulfate in the cement is normally consumed to form ettringite at early ages.
Is Tobermorite a zeolite?
This concrete, used in maritime harbors, contains Al-tobermorite, a mineral with a highly organized and very strong molecular structure, followed by crystallization of the zeolite crystal, phillipsite (Jackson et al., 2013).
Where is Portlandite found in nature?
Occurrence. Portlandite occurs in a variety of environments. At the type location in Northern Ireland it occurs as an alteration of calc–silicate rocks by contact metamorphism of larnite–spurrite. It occurs as fumarole deposits in the Vesuvius area.
What is muscovite hardness?
Muscovite has a Mohs hardness of 2–2.25 parallel to the [001] face, 4 perpendicular to the [001] and a specific gravity of 2.76–3. It can be colorless or tinted through grays, browns, greens, yellows, or (rarely) violet or red, and can be transparent or translucent.
Is Fuchsite transparent?
Verdite is a type of metamorphic rock made mostly of an impure, often multicolored, variety of fuchsite….
| Fuchsite | |
|---|---|
| Streak | White |
| Diaphaneity | Transparent to opaque |
| Specific gravity | 2.8–2.9 |
| References |
Why is Roman concrete not used today?
As it turns out, not only is Roman concrete more durable than what we can make today, but it actually gets stronger over time. This aggregate has to be inert, because any unwanted chemical reaction can cause cracks in the concrete, leading to erosion and crumbling of the structures.
Did the Romans invent the arch?
The Romans did not invent the arch. Indeed, arches have been used since prehistoric times. The ancient Egyptians, Babylonians, and Greeks all used it. As a result, Romans were able to build massive structures, such as aqueducts, which provided water to cities.