Remember the main components of Portland cement:
- \(C_3S\) (Tricalcium silicate or Alite) - Major component, early strength.
- \(C_2S\) (Dicalcium silicate or Belite) - Second major component, late strength.
- \(C_3A\) (Tricalcium aluminate or Celite) - Flash set.
- Gypsum is added to slow down the flash set caused by \(C_3A\).
Portland cement is a complex mixture of several compounds. The main constituents and their approximate percentages are:
1. Tricalcium silicate (Ca\(_3\)SiO\(_5\)), also known as Alite: This is the most abundant component, typically making up 50-60% of Portland cement. It is responsible for the initial set and early strength development.
2. Dicalcium silicate (Ca\(_2\)SiO\(_4\)), also known as Belite: This makes up about 15-30% of the cement. It hydrates more slowly and contributes to the long-term strength.
3. Tricalcium aluminate (Ca\(_3\)Al\(_2\)O\(_6\)), also known as Celite: This component is present in smaller amounts (5-10%). It reacts very quickly with water and contributes to the initial setting.
4. Tetracalcium aluminoferrite (Ca\(_4\)Al\(_2\)Fe\(_2\)O\(_{10}\)), also known as Ferrite phase: This makes up about 5-15% and contributes little to the strength.
Gypsum (CaSO\(_4\)\(\cdot\)2H\(_2\)O) is also added in small amounts (2-5%) to control the setting time by slowing down the rapid hydration of tricalcium aluminate.
Given the percentage of 51%, the major ingredient is Tricalcium silicate, Ca\(_3\)SiO\(_5\).
