FAQ’s About Cement
- A finely ground grey powder
- An inorganic compound of calcareous and argillaceous materials
- Used in combination with sand, aggregates, water and admixtures to get a versatile and economical construction material called “concrete”
- It is the main compound which binds all ingredients and gives strength to the concrete
Calcareous (limestone obtained from mines) and argillaceous (clay or bauxite) materials and iron ore are the most commonly used raw materials in the manufacture of cement.
- Extraction of limestone from the mines
- The blending of ground limestone, clay or bauxite and iron ore or laterite in the right proportions which is then clinkered in rotary kilns at a high temperature to form “clinker”
- Grinding of clinker with gypsum to form cement
- Finally, storing it in silos, testing and dispatch
Clinker is made by heating limestone with small quantities of corrective materials to 1400°C- 1500°C in a kiln. It is ground with gypsum to a powder to manufacture cement.
- Tri-calcium Silicate(C3S)
- Di-calcium Silicate(C2S)
- Tri-calcium Aluminate(C3A)
- Tetra-calcium Alumino-Ferrite(C4AF)
Commonly available cements are ORDINARY PORTLAND CEMENT(OPC) 53 GRADE conforming to IS 12269, ORDINARY PORTLAND CEMENT (OPC) 43 GRADE conforming to IS 8112, PORTLAND POZZOLANA CEMENT(PPC) conforming to IS 1489(PART I) AND PORTLAND SLAG CEMENT(PSC ) conforming to IS 455.