Introduction to Cement | Civil Engineering | Part I
- Cement is a material which has cohesive and adhesive properties in the presence of water.
- Cement is a product obtained by pulverizing clinker formed by calcinating raw-materials primarily consisting of Lime (CaO), Silicate (SiO2), Alumina (Al2O3) and Iron oxide (Fe2O3).
- It was invented by Joseph Aspdin of UK in 1824. He named it Portland Cement because the hardened concrete made out of the cement aggregate and water in definite proportion resembled the natural stone occurring at Portland in England.
- When cement is mixed with water it forms a paste which hardens and binds aggregates (fine and coarse) together to form a hard durable mass called concrete.
- Cement used in construction industry can be classified as hydraulic and non-hydraulic.
- Hydraulic cement set and harden in presence of water (due to chemical action bet. Cement and water called hydration) and results in water resistant product which is stable. E.g. Portland cement.
- Non-hydraulic cement are derived fro calcinations of gypsum or limestone because their products of hydration are not resistant to water; however, the addition of pozzolanic materials can render gypsum and lime cement hydraulic. E.g. Plaster of Paris.
- Cement can be manufactured either from natural cement stones or artificially by using calcareous and argillaceous material. E.g. of natural cements are Roman Cement, Pozzolona Cement and Medina Cement and of artificial cement are Portland cement and special cementsa.
Argillaceous
|
Calcareous
|
Shale and caly
|
Limestone
|
Cement rock
|
Chalk
|
Blast furnace slag
|
Marine shells
|
Marl
|
- Variuos varieties of artificial cement are available in the market at present.
Next Topic: Chemical Composition of Raw Materials
No comments:
Post a Comment