Cement

Cement is simply a 'binder,' a substance that when mixed with water will set and harden. It is able to bind materials together, or be used as a stand alone building material. The most common cement used in the modern world is Portland cement although there are other types such as Energetically Modified Cement and various cement blends.

Portland Cement is Made by Heating Limestone to a Temperature of 1,450 Degrees Celsius
Portland cement is made by heating limestone (calcium carbonate) with small amounts of other materials, usually clay, to a temperature of 1,450 degrees Celsius, in a kiln. This is known as calcination. When this occurs carbon dioxide is liberated from the limestone and forms quicklime, or calcium oxide, it also becomes blended with any other material that has been included in the mix. At this stage a hard product known as 'clinker' is created. The clinker is ground with small amounts of gypsum until it becomes a fine powder that is known as ordinary Portland cement, or OPC.

Cement is Mainly Used for the Making of Concrete
Portland cement is the basic ingredient required in the making of concrete, non-speciality grout and mortar. By far its greatest use is in the making of concrete that is the result of mixing Portland cement with gravel and sand (aggregate) and water. It is used widely in the construction industry because of its ability to be cast into almost any shape the architect desires. Once it dries it has great load bearing elements. Its natural colour is usually white or grey. Cement will set and harden independently as a concrete and is also able to bind other materials together as a mortar.

Romans Called Cement Opus Caementicium
The name cement originated with the ancient Romans who called it 'opus caementicium.' The Roman version of cement was made from burnt lime and crushed rock. Pulverised brick and volcanic ash was often added to the burnt lime to obtain a hydraulic binder that came to be called 'cementum.'

Portland Cement is hydraulic
Cement used for construction purposes can be either hydraulic or non-hydraulic. Portland cement is a hydraulic cement because it hardens as a result of the hydration effect caused by a chemical reaction that takes place between water and the anhydrous cement powder. This allows it to harden in wet conditions, even underwater. Non-hydraulic cement won't harden underwater. For example slaked lime requires atmospheric carbon dioxide to allow it to react and harden.

Cement was Used in Mesoptamia 300 Years B.C.
It is not known when cement was first used but it has been established that it was used in Mesopotamia at least 300 years B.C. This cement used a mixture of gravel, sand, lime and water to create concrete.

Modern hydraulic cement was developed during the Industrial Revolution in the 1800's.

This occurred because of three needs:
1. The need to develop strong concrete
2. The need to develop hydraylic mortars for masonry work in the building of structures that were in contact with salt water
3. The need for hydraulic cement render, often referred to as 'stucco' when finishing off brick building in wet climates

In Britain, as quality building stone became depleted and expensive, it was replaced with man made brick and finished off with stucco to give it the appearance of stone. Portland cement was developed by Joseph Aspdin in 1824. He named it Portland cement because its render colour was similar to that of Portland stone. Josephs Aspdin's son, William, made the first cement containing alite in the early 1840's. This was obtained by heating the lime to a higher temperature allowing the cement to set faster. This cement was what we refer to today as modern portland cement.