Bogues Compounds in Cement | Calculation of Bogues Compound

Cement manufacturing employs raw materials like lime, silica, alumina, and iron oxide. These oxides react in the kiln during cement manufacture at a higher temperature to form complex compounds. These compounds are called Bogue's Compounds. 

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The various bogues compounds in cement are:

1. Tricalcium silicate (C3S) - Alite
2. Dicalcium Silicate (C2S) - Belite
3. Tricalcium aluminate (C3A) -Aluminate Phase
4. Tetracalcium Aluminoferrite (C4AF)- Ferrite Phase

Pictorial Representation of Bogues Compounds Present in Cement

Chemical Composition of Cement - Bogues Compounds

The basic chemical composition of cement, i.e. Bogues Compounds are given in table 1. For convenience, they are given short forms as shown in the table. The significance of each compound is discussed in the following sections. The proportion of raw materials i.e. the oxides influence the quality and quantity of Bogues Compounds in cement. 

Table.1 

Bogues Compounds in Cement

Bogues Equation for Cement

Bogues equation is used to calculate the approximate proportions of the four main minerals in portland cement i.e. C₃S, C₂S,C₃A, and C₄AF.

The calculation is as follows:

1. C₃S = 4.0710CaO-7.6024SiO₂-1.4297Fe₂O₃-6.7187Al₂O₃
2. C₂S = 8.6024SiO₂+1.0785Fe₂O₃+5.0683Al₂O₃-3.0710CaO
3. C₃A = 2.6504Al₂O₃-1.6920Fe₂O₃
4. C₄AF = 3.0432Fe₂O₃

Hydration of Bogues Compounds in Cement

The chemical reaction that takes place between the cement and water is referred to as the hydration of the cement. The hydration reaction is an exothermic reaction.

During the reaction, there is a particular order in which each bogue compound reacts.

READ ON STAGES OF CEMENT HYDRATION OF BOGUE COMPOUNDS

Each reaction of compounds results in certain hydration products that influence the strength of the concrete. A quick idea on different hydration reactions in cement is mentioned below

C₃S + water → C-S-H + C-H + Heat
i.e. 2(3CaO.SiO₂) + 6H₂O  → 3CaO. 2SiO₂. 3H₂O + 3Ca (OH)₂ + Heat  

2C₂S + 4H → C-S-H + C-H 
2C₃A + 21H → C₄AH₁₃ + C₂AH₈ → 2C₃AH₆ + 9H

C₃A + 32H +3CaSO₄ → C₃A. 3CSH₃₂ → C₆AS₃H₃₂

C₆AS₃H₃₂  =(Calcium Aluminate Tri Sulphate Hydrate or Ettringite)

 

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HYDRATION PRODUCTS OF CEMENT