What is Cement
Cement is a powder which provide binding medium between fine & coarse aggregate. When it’s mixes with water in proper ratio after mixing it become paste and make bonds between soil and aggregate.
Its is different from lime (CaO) by properties that it is set readily but not slake. The setting power of cement is better than lime. Cement is a Calcareous material which is used in concrete & mortar for construction.
Types of Cement
Different types of cement are given below which are classified by its properties and the relevant Indian Standard.
- Ordinary Portland Cement (opc cement)
- Rapid Hardening Cement
- Low Heat Cement
- Sulphate Resisting Cement
- Quick Setting Cement
- High Strength Cement
- Portland Pozzolana Cement
- High Alumina Cement
- White Cement
Ingredients of cement
Mostly 8 type of ingredients is used to make Cement.
- Lime
- Silica
- Alumina
- Magnesia
- Sulphur trioxide
- Iron Oxide
- Calcium sulphate
- Alkaline
Note:- Normally Portland Cement is used for building and construction so we read about Portland Cement.
What is portland cement?
It is an extremely binding material which contains adhesive and cohesive properties which provide a medium for aggregate. Cement start chemical reaction with water & sets and harden with the help of air. It usually describes as hydraulic cement. Mostly typical raw material used for making Portland Cement are limestone, sand, state clay and iron oxide.
Portland Cement Manufacturing process
There are two way to manufacturing of cement known as “Wet” & “Dry” which are depending upon the whether mixing and grinding of materials.
Wet Process of Cement Manufacturing
In this process limestone crushed first to smaller fragments. Then put it in ball or tube mill where they mixed with clay & fine ground material. After that water is added to make slurry after that it pumped to slurry tank.
Slurry sprayed against hot surface of flexible chain; losses moisture become flakes in this process temperature reached up to 1500⁰C.
After that process material cooled under controlled conditions that fused material known as Clinker. Cooled clinker then ground in a ball mill with addition of 2 to 3% of gypsum.
Dry Process of Cement Manufacturing
According to its name in this process the raw material for cement is dried and ground to powder by grinding mill. Dry powder is blended and corrected for its right composition and mixed by table.
| Oxide | Percentage |
| Lime | 60-67% |
| Silica | 17-25% |
| Alumina | 3-8% |
| Iron Oxide | 0.5–0.6% |
| Magnesia | 1-3% |
| Sulphur Trioxide | 1-3% |
| Calcium Sulfate | 0.1–0.5% |
These oxide compositions are subjected to high temperature and combine with each other and form to complex material which are known as “Bogue’s compound”.
List of Bogue’s compound.
- Tricalcium silicate
- Dicalcium silicate
- Tricalcium aluminate
- Tetra calcium aminopherase.
Mixing of these compounds to make Portland Cement.
