Grading Limits for Grit (रोड़ी) or Coarse Aggregates as per IS code 383:2016 Clauses 6.1 and 6.2. This table outlines the percentage passing for different IS sieve sizes for both Single-Sized and Graded Coarse Aggregates.
ग्रिट (रोड़ी) या दरदरे भराव की ग्रेडिंग सीमा – IS कोड 383:2016 के क्लॉज 6.1 और 6.2 के अनुसार
यह तालिका विभिन्न IS छन्नियों (sieve) के लिए एकल-आकार और मिश्रित आकार दरदरे भराव की प्रतिशत पासिंग को दर्शाती है।
Table 7: Coarse Aggregates (IS 383:2016, Clauses 6.1 and 6.2)
Part 1: Percentage Passing for Single-Sized Aggregate of Nominal Size
This section specifies the percentage of coarse aggregate passing through various sieve sizes for single-sized aggregates with nominal sizes of 63 mm, 40 mm, 20 mm, 16 mm, 12.5 mm, and 10 mm.
| SI No. | IS Sieve Designation | 63 mm | 40 mm | 20 mm | 16 mm | 12.5 mm | 10 mm |
|---|---|---|---|---|---|---|---|
| i) | 80 mm | 100 | |||||
| ii) | 63 mm | 85–100 | 100 | – | – | – | – |
| iii) | 40 mm | 0–30 | 85–100 | 100 | – | – | – |
| iv) | 20 mm | 0–5 | 0–20 | 85–100 | 100 | – | – |
| v) | 16 mm | – | – | – | 85–100 | 100 | – |
| vi) | 12.5 mm | – | – | – | – | 85–100 | 100 |
| vii) | 10 mm | 0–5 | 0–5 | 0–20 | 0–30 | 0–45 | 85–100 |
| viii) | 4.75 mm | – | – | 0–5 | 0–5 | 0–10 | 0–20 |
| ix) | 2.36 mm | – | – | – | – | – | 0–5 |
Part 2: Percentage Passing for Graded Aggregate of Nominal Size
This section specifies the percentage of coarse aggregate passing through various sieve sizes for graded aggregates with nominal sizes of 63 mm, 40 mm, 20 mm, 16 mm, 12.5 mm and 10 mm.
| SI No. | IS Sieve Designation | 40 mm | 20 mm | 16 mm | 12.5 mm |
|---|---|---|---|---|---|
| i) | 80 mm | 100 | – | – | – |
| ii) | 63 mm | – | – | – | – |
| iii) | 40 mm | 90–100 | 100 | ||
| iv) | 20 mm | 30–70 | 90–100 | 100 | 100 |
| v) | 16 mm | – | – | 90–100 | – |
| vi) | 12.5 mm | – | – | – | 90–100 |
| vii) | 10 mm | 10–35 | 25–55 | 30–70 | 40–85 |
| viii) | 4.75 mm | 0–5 | 0–10 | 0–10 | 0–10 |
| ix) | 2.36 mm | – | – | – | – |
Annotations
Single-Sized vs. Graded Aggregates:
- Single-Sized Aggregates: These are aggregates with a predominant particle size within a narrow range, used for specific applications like drainage layers or high-strength concrete. The table ensures that most particles pass through the nominal size sieve but are retained on the next smaller sieve.
- Graded Aggregates: These have a wider range of particle sizes, providing better packing and workability in concrete mixes. Graded aggregates are commonly used in structural concrete.
Nominal Sizes:
- Nominal sizes (e.g., 63 mm, 40 mm) refer to the maximum size of the aggregate particles. The table ensures that aggregates meet specific grading requirements for each nominal size.
Sieve Sizes:
- The sieve sizes listed (e.g., 80 mm, 63 mm, down to 2.36 mm) are standard IS sieves used to determine the particle size distribution of coarse aggregates per IS 2386 (Part 1).
Percentage Passing:
- The ranges (e.g., 85–100, 0–5) indicate the acceptable percentage of aggregate passing through each sieve. A range like 0–5% means minimal material should pass through that sieve, ensuring the aggregate is retained above it.
Missing Values:
- Blank cells in the table indicate that the sieve size is not applicable for testing that particular nominal size (e.g., 80 mm sieve is irrelevant for 10 mm nominal size).
Application:
- Single-Sized Aggregates: Used where uniform particle size is critical, such as in high-performance concrete or drainage systems.
- Graded Aggregates: Preferred for general concrete works (e.g., RCC) due to better workability and strength from varied particle sizes.
Compliance:
- Aggregates must comply with Clauses 6.1 (general requirements for coarse aggregates) and 6.2 (grading requirements) of IS 383:2016. Additional tests for deleterious materials, alkali-aggregate reactivity, and physical properties (e.g., specific gravity, water absorption) are required per IS 2386.
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