Understanding Cement in Building Strong Structures

Important Considerations

• Grade and Date Check: Always check the grade and date of production of the cement bag to ensure it meets your project’s requirements. Using the correct grade of cement is crucial for the specific demands of your construction project.

1.  Grade 33 Cement:

• Usage: Typically used for plastering and finishing works.
  
• Strength: Achieves a compressive strength of 33 MPa (Mega Pascals) after 28 days of setting.
• Note: Less commonly used now due to the availability of higher strength cements.

2. Grade 43 Cement:

• Usage: Suitable for general construction work, including residential buildings, roads, and small bridges.
• Strength: Reaches a compressive strength of 43 MPa after 28 days.
• Note: Widely used in Bangladesh for its balanced strength and cost.

3. Grade 53 Cement:

• Usage: Ideal for high-strength construction projects like bridges, high- rise buildings, and heavy structures.
• Strength: Attains a compressive strength of 53 MPa after 28 days.
• Note: This grade is popular for projects requiring early strength gain.

• Always verify the grade:  Ensure that the cement grade matches the specific needs of your project. For example, for residential buildings, Grade 43 cement is usually sufficient, while for larger infrastructure, Grade 53 may be required.

• Covered Consignment:  Ensure the cement is covered during transportation, especially during the rainy season. Moisture can easily penetrate the bags during transit, leading to compromised quality.

•  Wet Cement Rejection: Do not accept wet cement under any circumstances as it compromises the quality and strength of the structure. Wet cement can start the hydration process prematurely, making it ineffective for construction use.

By understanding these aspects of cement, you can ensure that your construction materials are of the highest quality, leading to stronger and more durable structures. Proper selection, testing, and storage of cement are critical steps in building safe and long-lasting buildings.

Best Practices for Using Cement in Bangladesh

• Selecting the Right Cement for the Climate

In hot areas, using PPC (Portland Pozzolana Cement) is better because it sets slower and generates less heat, reducing the risk of cracks. Experts suggest that PPC is more durable in hot weather.

•  Ensuring Quality

Check Certifications: Make sure the cement has proper certifications like the Bangladesh Standards and Testing Institution (BSTI).

•  Proper Storage

Store cement in a dry place to avoid moisture, which can weaken its strength.

Mixing and Proportioning

• Proper Mixing:  Ensure that cement is mixed thoroughly with aggregates and water to achieve the desired consistency and strength.

• Correct Proportioning:  Use the correct ratio of cement, sand, and aggregates as specified for different types of construction.

Storage of Cement
Proper storage of cement is essential to maintain its quality and effectiveness. Here are some key storage tips:

• Shelf Storage: Cement should be kept on shelves in the house or warehouse to avoid direct contact with the floor. This prevents moisture from the ground from seeping into the cement bags.

• Distance from Walls: Cement bags should be kept at least 600 millimeters (2 feet) away from warehouse walls to prevent moisture absorption. Walls can transfer moisture, especially during the rainy season, which can compromise the quality of the cement.

•  Wooden Pallets: Store cement bags on wooden pallets or spread wood powder or husk on the floor of the warehouse to protect from ground moisture. This helps in creating a barrier between the cement bags and the ground.

• Stacking: When arranging, cement bags should be kept in stacks. A maximum of 10 bags can be placed one on top of the other. Ensure enough space between two piles for easy movement. Proper stacking prevents the bags from tearing and allows for better air circulation.

•  Water Protection: Cement should always be kept away from contact with water to prevent it from hardening. Ensure that the storage area is dry and well-ventilated to prevent moisture buildup.

• Opening: Cement bags should be opened only before mixing to retain their quality. Once exposed to air, cement can absorb moisture and lose its effectiveness.

• Storage Duration: Cement should not be stored for more than 6 months as it can lose its properties. Over time, cement can undergo chemical changes that reduce its strength and effectiveness.

• First-In-First-Out (FIFO): Use the old cement first before the new bags to ensure the cement remains fresh and effective. This practice helps in maintaining the quality of the cement used in construction.

By paying attention to the quality of cement through simple tests, understanding the different types of cement available, and ensuring proper storage practices, you can make informed decisions that enhance the integrity of your constructions.

Remember to always check the grade and production date, protect the cement from moisture during transportation and storage, and use the older stock first to maintain the quality of the cement. With these guidelines, you can ensure that your construction projects are built on a strong foundation, leading to safer and more resilient structures.