Definition and Characteristics
Limestone is a sedimentary rock composed of minerals such as silica, flint and calcium, making up 10% of the total sedimentary rock in the planet.
It is a soluble stone that erodes easily with weak acidic solutions or water.
It is usually a grey color, but depending on its chemical composition, it can be white, yellow or brown. Limestone is a soft rock that can easily be scratched.
Use in Buildings
Limestone is used in many different ways in the construction industry from structure to finishes.
During the middle ages, is was used as bricks in many medieval churches and castles, all with a Romanesque architectural style.
It is found commonly in European and North American buildings from the 19th to 20th century. Limestone was one of the most obtainable building materials and is easy to work with, but it is a relatively expensive. Train stations and banks commonly used limestone blocks. Skyscrapers would often use thin plate coverings for decorative purposes.
The most common structural use of limestone today is in cement and mortar. It is also used in tiles and for surface finishing.
Benefits and Drawbacks
Limestone, like marble, is reactive to acidic solutions. It weathers, erodes, stains, crumbles, chips, cracks, and flakes.
This becomes a problem for exterior limestone in areas that are unfortunate enough to be hit by acid rain.
This deterioration is commonly seen on historical buildings that date back to the age of the Egyptians.
Luckily for the Sphinx, the deterioration is only surface deep, and anything below is still intact.
A benefit is that it can often be a locally available material, meaning less CO2 (carbon dioxide) will be produced due to the reduced need of transportation.
- chemical feed-stock
- underground coal mines, suppressing methane explosions
- breads and cereals as a source of calcium