Cement Ingredients and Their Functions in Construction

Almost every construction project requires cement in one capacity or another. Therefore, the composition of cement is a matter of great interest to engineers and cement manufacturers. There are 8 major ingredients used in cement, altering the amount of each of these during cement production, you can achieve the desired quality of cement.

Composition of cement

The general percentage of each of these ingredients used in cement is given below:

• Lime: 60–65%
• Silica: 17–25%
• Alumina: 3–8%
• Magnesia: 1–3%
• Iron oxide: 0.5–6%
• Calcium Sulfate: 0.1–0.5%
• Sulfur Trioxide: 1–3%
• Alkaline: 0–1%

Let’s talk about these in further detail and see how they affect the quality of the cement.

1. Lime:

It is one of the most important ingredients in cement. About 60–65 % of cement constitutes of lime which contributes to its strength. Proper care should be taken in maintaining proportion to make the cement strong and durable. An excess of lime makes the cement unsound and can cause the cement to expand and disintegrate. In the case where lime is deficient, the strength of the cement is reduced and it causes the cement to set quickly.

2. Silica:

Silica (also called Silicon dioxide) makes up about 17–25 % of the cement constituent. This addition contributes to the strength of cement due to the formation of dicalcium and tricalcium silicates. The excess presence of this ingredient increases the cement strength but prolongs the cement’s setting time.

3. Alumina:

Alumina (also called Aluminium oxide) makes up about 3–8% of the total cement composition. This material imparts quick setting quality to the cement. The downside of this material is that it leads to the reduction of strength when present in excess amounts.

4. Magnesia:

If this material is used in the correct quantity, 1–3% in cement, it imparts the cement with its characteristic color and hardness. If it is used in excess amount, the quantity seriously affects the soundness of the cement.

5. Iron oxide:

This material (also called Ferric oxide) helps to impart color to the cement. If used in the right amount, usually 0.5–6%, it helps to impart the cement with its characteristic hardness and strength.

6. Sulfur trioxide:

It is present in very low quantity, only about 1–3%, to make the cement sound. Having this material in excess amount only contributes to making the cement unsound.

7. Alkaline

Alkaline should never exceed more than 1%. Excess of this material leads to efflorescence (the white chalky powder residue often found on the surface of concrete or brick walls)

8. Calcium sulfate

Calcium sulfate is present in cement in the form of gypsum. It is usually packed along with calcareous materials. It forms about 0.1–0.5% of the cement. Its main function is to increase the initial setting period of cement.

The chemical composition of Tansen OPC Cement, one of the best cement in Nepal grants it extra strength and high durability making it ideal for all kinds of construction works. Tansen OPC Cement’s manufacturing process is highly monitored at all phases to ensure that only the best quality product reaches the market.

Tansen cement is proud to manufacture one of the Best Cement in Nepal