The sand, as a natural fine aggregate, shall be obtained from approved sources and shall be used in concrete, mortar, and other construction works. The material shall be clean, washed, and free from organic matter, silt, clay, and other deleterious materials that could adversely affect the performance of the finished product. It shall conform to the requirements of the applicable standard (for example, IS 383 or its equivalent) and shall exhibit a uniform color and texture, indicating that no contaminants are present.
The material properties shall include a specific gravity of not less than 2.60 and a bulk density within the acceptable range specified by the referenced standard. In addition, the sand shall be well graded and have a fineness modulus within the typical range of 2.3 to 3.1. Sieve analysis shall be performed in accordance with standard test methods, and the percentage of material passing each sieve shall conform to the prescribed gradation requirements. Zone wise classification is used to indicate the coarseness or fineness of sand, where Zone I represents a coarser grading (with a higher proportion of larger particles), Zone II represents a medium grading, and Zone III represents a finer grading (with a higher proportion of smaller particles). Below is a table showing the approximate percentage passing for selected sieve sizes in each zone:
| Sieve Size (mm) | Zone I (% Passing) | Zone II (% Passing) | Zone III (% Passing) |
|---|---|---|---|
| 4.75 | 100 | 100 | 100 |
| 2.36 | 95 – 100 | 90 – 100 | 80 – 90 |
| 1.18 | 80 – 90 | 70 – 80 | 60 – 70 |
| 0.60 | 65 – 75 | 50 – 60 | 40 – 50 |
| 0.30 | 50 – 60 | 35 – 45 | 25 – 35 |
| 0.15 | 30 – 40 | 20 – 30 | 10 – 20 |
| 0.075 | 5 – 10 | 0 – 5 | 0 – 3 |
The natural moisture content of the sand shall not exceed 4% by weight. If the moisture content is higher, the sand shall be dried to the specified level prior to use to ensure consistency in the mix design and to prevent variability in the concrete work. The percentage of material passing the 75-micron sieve shall not exceed 5% so that excessive fines do not affect the workability and strength of the concrete.
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Quality control of the sand shall be maintained by conducting regular tests for gradation, specific gravity, water absorption, and the presence of deleterious substances, following the standard test methods prescribed in the applicable standards. All test results shall be documented, and the material shall be rejected if the test results deviate from the prescribed limits.
Storage and handling of the sand shall be carried out in a dry, covered area to prevent moisture absorption and contamination. During handling and transportation, care shall be taken to avoid segregation of particles by size, thereby maintaining the uniformity of the sand. The storage area shall also be protected from environmental factors that could lead to degradation of the material quality.
The quantity of sand delivered shall be measured by weight using calibrated equipment to ensure accuracy, and payment shall be based on the verified weight of sand delivered to the site, as recorded in the delivery documentation and confirmed by onsite testing where applicable.
Environmental considerations shall be addressed by ensuring that the sand is free from hazardous substances and that it complies with local environmental regulations. The supplier shall provide documentation confirming that the sand is sourced and handled in an environmentally responsible manner and that all applicable safety and occupational health guidelines have been observed.
The supplier shall furnish a certificate of compliance with the applicable standard (e.g., IS 383) along with detailed test reports for each batch delivered. Records of all quality control tests, including gradation analysis, moisture content, and specific gravity, shall be maintained and made available for review by the Engineer. Finally, the specifications for sand shall be cross-referenced with the relevant sections of the contract documents and drawings, and any discrepancies between these documents shall be resolved in accordance with the established contractual dispute resolution procedures, with the specifications taking precedence.
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