This comprehensive guide explains flyash embankment construction in accordance with IRC: SP: 58-2001 and MoRT&H specifications. Learn materials selection, core design, earth cover, compaction methods, quality control, and safety measures for flyash embankment construction.
All materials must be approved by the Engineer. The core material is flyash, encapsulated by earth cover to ensure stable flyash embankment construction and durability for highway projects.
| Property | Typical Range | Notes |
|---|---|---|
| Appearance | Fine powder, grey to tan | N/A |
| Fineness | Mostly < 0.075 mm | Fine-grained material suitable for embankment cores |
| Specific Gravity | 1.90–2.55 | Lower than most soils |
| Dry Density (Loose) | 0.9–1.2 g/cc | Minimum required for compaction |
| Compacted Dry Density | 1.0–1.4 g/cc | Varies with compaction method |
| Permeability | 10⁻⁴–10⁻⁷ cm/sec | Low but higher than cohesive soils |
| Plasticity | Non-plastic | Ideal for embankment cores |
| pH | 8–10 (Alkaline) | Influences leachate |
| Parameter | Typical Range | Notes |
|---|---|---|
| Angle of Internal Friction (φ) | 25°–35° | Good frictional strength |
| Cohesion (c) | Low–Moderate | Often assumed zero in design |
| Maximum Dry Density (MDD) | 0.9–1.6 g/cc | IS: 2720 Pt 8 |
| Optimum Moisture Content (OMC) | 18%–38% | Helps achieve compaction |
| Location / Condition | Minimum MDD | Plasticity Index (PI) | Notes |
|---|---|---|---|
| Embankment H ≤ 3 m | ≥ 1.52 g/cc | 5–9% | No expansive soils |
| Embankment H > 3 m / Flooding | ≥ 1.60 g/cc | 5–9% | Chemical testing needed |
| Subgrade / Shoulder | ≥ 1.75 g/cc | N/A | Top 0.5 m of embankment |
Download All Flyash Embankment Reference Documents (PDF)
| Roller Type | Max Loose Layer |
|---|---|
| Vibratory Roller (80–100 kN) | 400 mm |
| Static Roller (80–100 kN) | 200 mm |
| Location | Required Density |
|---|---|
| General Embankment | ≥ 95% MDD |
| Bridge Abutments | ≥ 100% MDD |
| QC Test | Code | Frequency |
|---|---|---|
| Atterberg Limits | IS: 2720 Pt 5 | 2 / 3000 m³ |
| Modified Proctor | IS: 2720 Pt 8 | 2 / 3000 m³ |
| Moisture Content | IS: 2720 Pt 2 | 1 / 250 m³ |
| Field Density | IS: 2720 Pt 28 | 1 / 1000 m² |
Standard construction methodologies for highway works as per MoRTH 5th Revision and IRC Specifications.
