NAME
|
CHEMICAL NAME
|
SHORTLY CALLED AS
|
GENERAL FORMULA
|
LEVELS (%)
|
CHEMICAL FORMULA
|
Alite
|
Tricalcium silicate
|
C3S
|
3CaO.SiO2
|
45% to 65%
|
Ca3SiO5
|
Belite
|
Dicalcium silicate
|
C2S
|
2CaO.SiO2
|
15% to 32%
|
Ca3SiO4
|
Aluminate
|
Tricalcium aluminate
|
C3A
|
3CaO.Al2O3
|
7% to 14%
|
Ca3Al2O6
|
Ferrite
|
Tetra calcium alumino ferrite
|
C4AF
|
4CaO.Al2O3.Fe2O3
|
6% to 20%
|
Ca2AlFeO5
|
Gypsum
|
CaSO4.2H2O
|
2% to 10%
|
CaSo4.2H2O
|
C3S imparts early strength to cement(first 7 days strength).
C2S imparts later strength to cement (strength after 7 days).
C3A imparts setting to cement. Cement sets due to this C3A only.
C4AF imparts colour to cement.
Gypsum delays the setting time of cement. Without gypsum C3A in cement makes cement to flash set (to set immediately).
The following diagram gives you a rough idea about cement compound values:
The levels (%) of C3S, C2S, C3A & C4AF varies according to cement types. (for example to produce white cement, we require low C4AF etc.,)
C3S, C2S, C3A & C4AF are visible under microscope only. They are not predicted directly by lab tests, but they are indirectly calculated by using standard formulaes using lab chemical analysis results.
clinker microscopic images
where periclase is magnesium oxide (MgO)
