IS 2386:1963 Part 3 is the Indian Standard (BIS) for methods of test for aggregates for concrete - part 3: specific gravity, density, voids, absorption and bulking. This standard specifies the methods for determining the specific gravity, apparent specific gravity, water absorption, bulk density, voids, and bulking of fine and coarse aggregates to evaluate their suitability for concrete mixes.
Covers methods for determining specific gravity, bulk density, voids, water absorption, and bulking of fine aggregates.
Specific gravity, water absorption, bulk density and voids of concrete aggregates.
| Reference | Value | Clause |
|---|---|---|
| Specific gravity — typical natural aggregate | 2.6–2.8 | Cl. 3 (typical) |
| Specific gravity — basalt | 2.8–3.0 | (typical) |
| Specific gravity — light-weight (LECA) | 0.6–1.4 | (typical) |
| Pycnometer method — coarse aggregate | for 4.75–10 mm size | Cl. 3.2 |
| Wire-basket method — coarse aggregate | for ≥ 10 mm | Cl. 3.1 |
| Pycnometer method — fine aggregate | for ≤ 4.75 mm | Cl. 4.2 |
| Test temperature | 27 ± 2 °C | Cl. 1.2 |
| Soaking duration before test | 24 ± 0.5 hours | Cl. 3.1.4 |
| Water absorption — typical natural aggregate | 0.5–2.0 % | Cl. 3.5 (typical) |
| Water absorption — limestone | 1–4 % | (typical) |
| Water absorption — limit (IS 383) | ≤ 2 % (most aggregate) | (IS 383 Cl. 5.2) |
| Bulk density — loose (rodded) | ≈ 1500–1600 kg/m³ (typical) | Cl. 6 (typical) |
| Bulk density — compacted | ≈ 1600–1750 kg/m³ (typical) | Cl. 6 (typical) |
| Voids in aggregate — typical | 30–45 % | Cl. 6 (typical) |
| Voids formula | % voids = 100 (1 − bulk/SG ratio) | Cl. 6.4 |
| SSD condition (saturated surface dry) | drained but with absorbed water | Cl. 3.1.4 |
| Apparent specific gravity | = mass dry / volume permeable solids | Cl. 3.1.5 |
| Absolute volume basis (mix design) | = mass / (SG × 1000) | (applied in IS 10262) |
| Sample mass — coarse aggregate (40 mm) | 5 kg | Cl. 2.2 (Table 1) |
| Sample mass — coarse aggregate (20 mm) | 2 kg | Cl. 2.2 (Table 1) |
IS 2386 Part 3 (1963) provides Methods of Test for Aggregates for Concrete — Part 3: Specific Gravity, Density, Voids, Absorption + Bulking. The companion test reference for concrete aggregates alongside Part 1 (gradation), Part 5 (soundness) + other parts.
Use when: - Determining bulk density of aggregates for mix design - Calculating water absorption + porosity of coarse aggregate - Computing specific gravity for concrete mix design (per IS 10262:2019) - Checking bulking of sand for water-cement ratio adjustments - Aggregate acceptance testing per IS 383
Specific gravity (SSD - Saturated Surface Dry): 2.6-2.9 typical for granite / basalt; 2.2-2.6 for limestone
Water absorption: ≤ 2 % (preferred); ≤ 5 % acceptable for general concrete
Bulk density (loose / compacted): - Coarse aggregate: 1400-1700 kg/m³ (loose); 1600-1900 (compacted) - Fine aggregate: 1500-1700 kg/m³
Voids: typically 35-45 % loose; 30-40 % compacted
Bulking of sand: factor varies with moisture; max ~25-30 % at 4-6 % moisture
Test procedures per IS 2386 Part 3: - Specific gravity via pycnometer or wire-basket - Absorption: 24-hour soaking, SSD weighing - Density: standard cylinder + tamping - Voids = (1 - bulk density / specific gravity) × 100 - Bulking: dry vs wet sample volumes
Specific gravity (typical Indian aggregates): - Granite: 2.65-2.75 - Basalt: 2.7-2.9 - Sandstone: 2.4-2.6 - Limestone: 2.4-2.7
Water absorption acceptance: - ≤ 2 %: high-quality (preferred) - 2-3 %: acceptable for general concrete - > 3 %: requires moisture control in mix design
Bulk density use: - For mix design ratios (per IS 10262:2019) - For volume estimation in BOQ - For aggregate procurement planning
1. Wet sample tested without drying → false specific gravity. 2. Wrong saturated condition → SG variable. 3. Bulking of sand ignored in volume batching → wrong cement quantity. 4. Single sample for whole stockpile → variability not captured. 5. Lab equipment not calibrated → results inaccurate.
1. Aggregate source qualified per IS 2386 Part 3 + other parts. 2. Mix design uses SG + absorption per IS 10262:2019. 3. Production: periodic verification per shipment. 4. Quality control: site cube tests verify mix performance. 5. Long-term: aggregate quality contributes to concrete service life.
IS 2386 Part 3 is a routine but essential test reference for Indian concrete construction.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Standard Sieve Series (Coarse) | 80, 63, 40, 20, 10, 4.75 mm | 75 (3"), 50 (2"), 37.5 (1.5"), 25 (1"), 19 (3/4"), 9.5 (3/8"), 4.75 mm (No. 4) | ASTM C136 / C136M |
| Flakiness Criterion | Thickness < 0.6 × mean sieve size | Particles passing through slots of a bar sieve with opening D/2 (where D is sieve size) | BS EN 933-3 |
| Elongation Criterion | Length > 1.8 × mean sieve size | Ratio of length to width > specified value (e.g., 3:1); value is not fixed by the standard. | ASTM D4791 |
| Separator for Fine/Coarse Aggregate | 4.75 mm IS Sieve | 4.75 mm (No. 4) Sieve | ASTM C136 / C136M |
| Sieving Time (Mechanical Shaker) | Not less than 2 minutes. Sieving is complete when no more than 1% of residue passes a sieve in 1 minute. | No specific time, but sieving is complete when no more than 0.5% by mass of the total sample passes any sieve during 1 minute. | ASTM C136 / C136M |
| Shape Test Apparatus | Thickness Gauge (for flakiness) and Length Gauge (for elongation). | Proportional Caliper Device. | ASTM D4791 |
| Basis of Calculation (Shape) | Index is the mass of flaky/elongated particles as a percentage of the total mass tested. | Percentage by mass or by particle count of particles exceeding a specified dimensional ratio. | ASTM D4791 |