Water absorbing Portland cement

Water absorbing Portland cement is NOT a type of Portland cement. The correct answer is option 'C'.

Portland cement is a widely used construction material that is typically used as a binder in concrete and mortar. It is known for its strength and durability. There are several types of Portland cement available, each with its own unique properties and characteristics.

Types of Portland cement:

1. Ordinary Portland cement (OPC): This is the most commonly used type of Portland cement. It is suitable for general construction purposes and has a moderate setting time.

2. Rapid hardening Portland cement: This type of cement has a higher rate of strength development compared to ordinary Portland cement. It is often used in situations where quick strength gain is required, such as in cold weather concreting or for emergency repairs.

3. Water resistant Portland cement: This type of cement is designed to reduce the permeability of concrete, making it more resistant to water penetration. It is commonly used in structures that are exposed to water or moisture, such as basements, swimming pools, and water tanks.

4. Water repellent Portland cement: This type of cement contains additives that help to repel water and prevent its absorption into the concrete. It is often used in areas with high humidity or in structures that are exposed to frequent wetting and drying cycles.

5. Water proof Portland cement: This type of cement provides a higher level of water resistance compared to water repellent Portland cement. It is used in applications where a high degree of water tightness is required, such as in tunnels, dams, and underground structures.

Conclusion:

Among the given options, water absorbing Portland cement is not a type of Portland cement. The other options, including water proof Portland cement, water repellent Portland cement, and rapid hardening Portland cement, are all valid types of Portland cement with specific properties and applications.