IS 2720:1986 Part 17 is the Indian Standard (BIS) for methods of test for soils - part 17: determination of compaction properties (standard proctor). This standard details the laboratory method to determine the relationship between moisture content and dry density of soils using light compaction (Standard Proctor test). It is used to identify the Optimum Moisture Content (OMC) and Maximum Dry Density (MDD) crucial for field compaction control.
Describes the standard Proctor test for determining the moisture-density relationship of soils.
Standard and modified Proctor compaction tests. MDD, OMC, sample preparation.
| Reference | Value | Clause |
|---|---|---|
| Method 1 — Standard Proctor (light) | 2.6 kg rammer, 310 mm fall | Cl. 4 (Method I) |
| Method 2 — Modified Proctor (heavy) | 4.9 kg rammer, 450 mm fall | Cl. 5 (Method II) |
| Mould — small (≤ 20 mm aggregate) | 100 mm dia, 1000 cm³ | Cl. 4.1 / 5.1 |
| Mould — large (> 20 mm aggregate) | 150 mm dia, 2250 cm³ | Cl. 4.1 / 5.1 |
| Layers — Standard Proctor | 3 layers (small mould) | Cl. 4.4.2 |
| Layers — Modified Proctor | 5 layers | Cl. 5.4.2 |
| Blows per layer — small mould | 25 (Standard) / 25 (Modified) | Cl. 4.4.2 / 5.4.2 |
| Blows per layer — large mould | 56 (Standard) / 56 (Modified) | Cl. 4.4.2 / 5.4.2 |
| Compactive effort — Standard | 595 kJ/m³ | Cl. 4 (informative) |
| Compactive effort — Modified— ≈ 4.5× Standard | 2700 kJ/m³ | Cl. 5 (informative) |
| Number of points on compaction curve | ≥ 4 (preferably 5) | Cl. 4.5 |
| Moisture spacing between trials | ≈ 2 % increments | Cl. 4.4.1 |
| Maximum dry density (MDD) — typical clay— value reported by test | 1.55–1.85 g/cm³ | (typical) |
| Optimum moisture content (OMC) — typical clay— value reported by test | 12–22 % | (typical) |
| MDD — typical sand | 1.85–2.10 g/cm³ | (typical) |
| OMC — typical sand | 8–14 % | (typical) |
| Reuse of compacted soil | Not permitted (changed structure) | Cl. 4.4.4 |
| Sample passing — small mould test | 20 mm | Cl. 4.2 |
| Sample passing — large mould test | 40 mm | Cl. 4.2 |
| Reporting accuracy | MDD to 0.01 g/cm³, OMC to 0.1 % | Cl. 4.7 |