Sample Detailed Specification for Cement
Ordinary Portland Cement (OPC) 53 Grade shall conform to IS 12269 and be suitable for structural concrete, masonry, plastering, and other civil engineering applications. The cement shall be free from lumps, impurities, or foreign matter and be supplied in fine, dry powder form with a uniform grey color. Packaging shall be in 50 kg moisture-proof bags.
The chemical composition of the cement shall meet the following requirements:
| Component | Permissible Limit (%) |
|---|---|
| Lime (CaO) | 60 - 67 |
| Silica (SiO₂) | 17 - 25 |
| Alumina (Al₂O₃) | 3 - 8 |
| Iron Oxide (Fe₂O₃) | 0.5 - 6 |
| Magnesia (MgO) | ≤ 6 |
| Sulphur Trioxide (SO₃) | ≤ 3 |
| Loss on Ignition (LOI) | ≤ 4 |
| Insoluble Residue | ≤ 2 |
Physical properties shall comply with IS 12269 standards. The specific gravity shall be 3.15 ± 0.03, and the fineness, as determined by Blaine’s method, shall not be less than 225 m²/kg. Standard consistency shall range between 26% and 33%. The initial setting time shall not be less than 30 minutes, while the final setting time shall not exceed 600 minutes. The compressive strength shall meet the following minimum requirements:
| Age of Test | Compressive Strength (MPa) |
|---|---|
| 3 days | 27 MPa |
| 7 days | 37 MPa |
| 28 days | 53 MPa |
Cement shall be stored in a dry, well-ventilated area on an elevated platform to prevent moisture absorption. Stacking shall be limited to ten layers of bags to avoid lump formation. The material shall be used within 90 days from the date of manufacture to ensure quality retention.
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Testing and quality control shall be carried out as per IS 4031, including fineness testing using Blaine’s air permeability apparatus, consistency testing with the Vicat Apparatus, and setting time determination. Compressive strength shall be tested using cube specimens of mortar at 3, 7, and 28 days, and the soundness of cement shall be checked through the Le Chatelier method.
Tolerances shall comply with IS limits, ensuring that compressive strength does not fall below the specified values, and fineness variation shall not exceed ±10% from the standard. The initial setting time shall not be less than 30 minutes, and the final setting time shall not exceed 600 minutes.
Measurement shall be based on the actual quantity used at the site and recorded accordingly. The unit of measurement shall be per metric ton or per 50 kg bag. Payment shall be made based on verified site records.
Handling precautions shall be followed to minimize health and environmental risks. Workers shall wear protective gear such as masks and gloves to avoid respiratory and skin issues. Disposal of excess cement shall be done following environmental regulations, ensuring that the material is not discharged into water bodies.
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