Cement Composition: It is heavy and very fine powder in gray color. When mixed with water and sand, it forms a compact paste. Which slowly hardens like a Portland stone. For this reason, it is also called Portland cement.
Portland cement was discovered in 1824 by Joseph Seldin, a resident of Leeds in England. It is a very useful material and it is used in making buildings, bridges, etc.
What is cement made of?
Cement is the main mixture of calcium silicones and aluminates. Its composition depends on the raw materials and method of making it. Its organization is almost as follows.
- Calcium Oxide: – 50-60%
- Silica – 20-25%
- Alumina – 5-10%
- Magnesium oxide – 2-3%
- Ferric oxide – 1-2%
- Sulfur trioxide – 0-1%
- Gypsum – 2-5%
Cement Composition
To make cement, each stone is grinding separately by taking suitable quantities of sand and smooth clay.
These are then mixed and heated to about 1500°C in a revolving furnace. On doing this, calcium silicates and aluminates are formed. And gases like carbon dioxide, water vapor, etc., come out of the furnace. The green and gray granular material obtained in this way are called cement clinker.
The structure of silicates depends on the following structural unit.
On this basis, the following are the lists of Si2O64-, Si2O76- and Si3O96-.
The cement clinker is cooled and grinded the mixture by mixing 2 to 5% of gypsum. Thus Portland cement is obtained.
By adding gypsum to the cement clinker, it controls the freezing time of the cement and water mixture.
The setting of cement
After leaving the mixture of cement and water open, it slowly forms a hard substance. This action is called the setting of cement. This estimate is made. That in this action, the hydration of calcium silicates and laminates occurs. Water addition results in the formation of polymers with a long chain and hybrid joints.
Such structure polymers are obtained as a result of the water addition of silicates.
Due to the formation of polymer material, cement components are interconnected. And a hard substance is obtained. Which is called cement freezing.
Calcium silicates and aluminates are fast freezing substances. On adding water in the presence of gypsum, the hydrated substances combine with gypsum to form other substances which do not freeze quickly.
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