Proper storage of cement is essential to preserve its quality and effectiveness in construction. Due to its hygroscopic nature, cement readily absorbs atmospheric moisture, which can cause it to harden into a stone-like substance that becomes unusable for construction purposes. This article outlines key precautions in storing cement, detailing specific measures for protecting it from factors like atmospheric moisture, storage duration, location, arrangement of bags, and withdrawal processes.
Key Precautions for Cement Storage
Maintaining the quality of cement depends on several critical storage conditions. Here are the factors influencing cement storage:
- Atmospheric moisture content: Cement’s ability to absorb moisture necessitates stringent measures to minimize exposure to damp environments.
- Duration of storage: Longer storage times impact cement strength, so managing the length of storage is vital.
- Place of storage: Properly constructed storage areas protect against moisture damage.
- Arrangement of cement bags: Organizing cement bags correctly helps prevent unnecessary exposure and prolongs shelf life.
- Withdrawal process: A systematic method of removing bags ensures the oldest cement is used first, maintaining overall quality.
Precautionary Steps for Proper Cement Storage
1. Moisture Content at Place of Storage
Moisture in the atmosphere is a primary threat to cement. Even trace moisture can cause cement to become unusable. Cement should always be stored in airtight bags to minimize exposure. High-quality cement with a fine grain absorbs moisture more aggressively, requiring extra care to prevent contamination.
If cement is exposed to atmospheric moisture, it’s essential to test the material for usability. A moisture content above 5% generally renders the cement unfit for construction, as its chemical integrity may be compromised. Therefore, controlling exposure and monitoring moisture levels is a fundamental aspect of cement storage.
2. Duration of Cement Storage
Storage duration is another factor that impacts cement’s effectiveness. Over time, cement’s strength diminishes, with recommended storage time capped at three months for optimal results. When cement must be stored beyond this period, it’s crucial to test its strength before using it in any construction. The table below illustrates how extended storage reduces cement strength:
| Period of Storage | Fresh Stage | 3 Months | 6 Months | 1 Year | 5 Years |
|---|---|---|---|---|---|
| % Reduction in Strength | 0% | 20% | 30% | 40% | 50% |
For cement stored for long periods with decreased strength, techniques like vibro grinding can help restore usability. This process improves the fineness of older cement, reactivating it to meet construction requirements. However, prevention through limited storage time is always the preferred approach.
3. Place of Cement Storage
Cement bags should never be stored in open or unprotected spaces. A specially designed storage shed is recommended for optimal protection, featuring waterproof floors, walls, and roofs to shield against moisture. The floor of the storage shed should be raised above ground level to avoid any ground moisture from seeping in.
The shed should have minimal openings, with small, airtight windows and doors, as well as proper drainage systems to prevent water accumulation. For effective space planning, each cubic meter of storage accommodates about 20 cement bags, each weighing approximately 50 kg. Storage shed dimensions should be designed according to the expected volume of cement to ensure a suitable environment.
4. Arrangement of Cement Bags
Inside the storage shed, cement bags should be arranged in a structured manner to prevent unnecessary exposure to moisture. A wooden platform, 150 to 200 mm high, should be placed above the floor to keep bags from contacting it directly. Bags should be stacked no more than 10 high to prevent the risk of collapse, with each stack at least 300 mm away from walls to improve air circulation.
A passage of 900 to 1000 mm should separate stacks to allow easy access and ventilation. Stacks should be arranged crosswise, which stabilizes them and reduces the likelihood of shifting or collapsing. Covering stacks with a waterproof layer ensures protection over long storage durations, and marking each stack with the storage date helps track their age and ensures the most recently stored cement is used first.
5. Withdrawal of Cement Bags
When it’s time to use the stored cement, the bags should be withdrawn using a First-In, First-Out (FIFO) approach. This means the cement bags placed in storage first should be withdrawn first. This method ensures the cement does not remain stored longer than necessary, thus preserving its quality and strength.
Conclusion
Proper storage of cement is crucial for maintaining its quality and strength, which directly affects the durability of the construction. From protecting it against atmospheric moisture to organizing its arrangement in the storage shed, each precaution helps ensure that cement remains in optimal condition. With these steps, construction projects can benefit from the full strength and effectiveness of the cement, avoiding costly rejections and maintaining structural integrity over time.