Description
Cement is a hydraulic binder, i.e. when mixed with water it forms a paste which sets and hardens (hydraulic properties). It is used in powder form to make concrete or mortar.
Cements can be classified into five main families and 27 main variants (see standard EN-197-1-2000) for more details:
Portland cement (CEM I rated)
Portland cement compound (rated CEM II)
Blast furnace cements (rated CEM III)
Pozzolanic cements (rated CEM IV)
Slag and ash cements or compound cement (rated CEM V)
Other names: The word “cement” can refer to different materials such as:
The plaster
common lime,
Natural pozzolan
Quick cement,
Portland cement or artificial cement
Glossary of cements:
Alumina cement
Aluminous cement was invented by J. Bied, scientific director of Ciments Lafarge, in 1908 and produced industrially in France from 1918. It is a cement based on calcium aluminates. Portland cements contain calcium silicates. These aluminates do not release lime during hydration and provide several special properties to alumina concrete or mortar:
A quick take
High chemical resistance
High wear resistance
Resistance to high temperatures
A cold weather setting accelerator
artificial cement
Artificial cement, or Portland cement, is an artificial (man-made) mixture of 76-80% carbonate of lime, and 24-20% clay, ground and mixed raw, then fired at a temperature of 1,450°C to obtain a very hard artificial rock, the clinker, ground again very finely, gives the artificial cement.
It is a slow cement, produced in large quantities from around 1850, used today for common concrete and reinforced concrete, as well as for high-tech work such as bridges and roads or engineering structures. Its long and complicated manufacture made it expensive for a long time. It was imitated cheaply by what can be called “artificial fakes”.
In 1897, the Materials Test Method Commission classified all slow-setting cements in the same category, and from 1902, the Lime and Cement Commission no longer used this term artificial and included it. in Portland cements.
White or extra-white cement
White or extra-white cement is a Portland cement without metallic oxide (a kind of heavy lime), intended for the manufacture of tiles or moldings. It is remarkable for its fineness and whiteness, producing no chapping on the smooth surface. It was invented in 1870. It is taken between 6 and 15 hours.
Burnt cement (or clinker)
Clinker, fired at 1,450°C and not yet ground, can be used as cement, in which case we speak of burnt cement. He is very tough. Its setting is much slower than cements moderately baked at 1000°C, but it exhibits quite extraordinary hardening and degree of cohesion.
Crushed and mixed with gypsum to delay setting, it is the basis of the common manufacture of modern ordinary cements (Portland cement). In the 19th century in Dauphiné, the moderately cooked pieces, often yellow in color, were called yellow frittes or logs. The overcooked pieces were called black frits. The word clinker, imported from the United Kingdom, was mainly used to designate the black frits of artificial portland cement.
ash cement
Ash cements were manufactured for the first time in France in 1951, by P. Fouilloux.
Molten cement
Cement from the beginning of the 20th century, very aluminous, of normal setting, whose hardening requires a lot of water, releases a lot of heat and is very fast. It is indecomposable in magnesian and selenitous waters, mixes poorly with other cements, and is expensive.
Grape cements
The production of grappiers’ cements began around 1870. Grappiers are the hard elements that the action of water cannot make fall into powder during the extinction of the lime, and that the bolters rejected. These were the uncooked, overcooked, borderline lime and parts that were too loaded with clay from the marl limestones.
Constituting a significant loss for the manufacturer, we ended up in Teil (Ardèche) to take advantage of it by creating grappier cement, the quality of which could be remarkable. This somewhat bastard product disappeared definitively from the market with the 1914 war, but it is found in the architecture manuals of the 1930s.
slag cement
Cement also called pozzolan cement, obtained from blast furnace slag mixed with slaked fat lime and hydraulic lime.
The slag, to acquire power, must have been cooled abruptly on leaving the furnace by being thrown into water. It contains sulphides of calcium which oxidize in the air, which give it a green tint.