Question

The major component/ingredient of Portland Cement is :

• A. tricalcium aluminate
• B. dicalcium aluminate
• C. tricalcium silicate
• D. dicalcium silicate

Hint:

In cement production, Gypsum (\( \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \)) is added to slow down the setting process so it can be worked for a longer period.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Portland cement is a complex mixture of silicates and aluminates of calcium produced by heating limestone and clay.
Step 2: Detailed Explanation:
The approximate percentage composition of Portland cement is:
- Tricalcium silicate (\( 3\text{CaO} \cdot \text{SiO}_2 \)): \( 45-51% \)
- Dicalcium silicate (\( 2\text{CaO} \cdot \text{SiO}_2 \)): \( 20-25% \)
- Tricalcium aluminate (\( 3\text{CaO} \cdot \text{Al}_2\text{O}_3 \)): \( 5-10% \)
- Other oxides (MgO, \( \text{Fe}_2\text{O}_3 \)): Small amounts.
Tricalcium silicate is the major component and is responsible for the early strength of concrete.
Step 3: Final Answer:
Tricalcium silicate is the primary ingredient of Portland cement.