In the cement manufacturing process, the calcareous and argillaceous are collected in the kiln in proper proportion and burnt at a temperature of about 1400°C to 1500°C, this burnt material is then ground to form clinker of diameter 2 to 3mm.
Now the required amount of gypsum and water is added to the clinker, the added water reacts with ingredients chemically and results in the formation of complex chemical compounds which were identified first time by R.H. Bogue’s so called as bogues compounds.
When water is added to the cement it reacts with ingredients chemically and results in the formation of complex chemical compounds which were identified first time by R.H. Bogue’s so called as bogues compounds.
Basically there are four major bogues compounds namely Tricalcium Silicate, Dicalcium Silicate, Tricalcium Aluminate, and Tetracalcium Aluminoferrite.
The following table shows chemical composition of bogues compounds with their formula and abbreviated name.
|Name of Compound||Name||Formula||Abbreviated Formula||Percentage|
|Tricalcium Silicate||Alite||3CaO.SiO2||C3S||25 to 50%|
|Dicalcium Silicate||Belite||2CaO.SiO2||C2S||20 to 45%|
|Tricalcium Aluminate||Celite||3CaO.Al2O3||C3A||5 to 12%|
|Tetracalcium Aluminoferrite||Felite||4CaO.Alf2O3.Fe2O3||C4AF||5 to 10%|
As the chemical formulas of all the compounds are difficult to remember for simplicity abbreviated notations are used as shown in the table above like C- CaO, S- SiO2
Following are the properties and uses of tricalcium silicate
Following are the properties and uses of dicalcium silicate
Note: C3S and C2S contributesabout 70 to 80% of the cements overall strength.
Following are the properties and uses of tricalcium aluminate
following are the properties and uses of tetracalcium aluminoferrite
Note: C3A and C4AF hydrates rapidly but contribution to strength is insignificant.
Bogue’s equations are suggestions by bogue to calculate the percentage of all four bogues compounds. Bogues equations to calculate the percentage composition of bogues compounds are given below
C3S = 4.07 (CaO) – 7.60 (SiO2) – 6.72 (Al2O3) – 1.43 (Fe2O3) – 2.85 (SO3)
C2S = 2.87 (SiO2) – 0.754 (3CaO.SiO2)
C3A = 2.65 (Al2O3) – 0.754 (Fe2O3)
C4AF = 3.04 (Fe2O3)
The oxides inside the brackets represent the percentage composition of the same in the raw materials.
C3S > C2S > C3A > C4AF
C3A > C3S > C4AF > C2S
C3A > C3S > C4AF > C2S
Tricalcium Silicate results in long term strength of cement.
C3A gives out highest heat of hydration about 40% more than C3S.