Building a Bituminous Trunk Road Across 76.2 km of Niger State
The Beji–Jangara–Wushishi Section III contract delivered 76.2 km of trunk road to bituminous-pavement standard. Every quantity below was measured and certified by the Engineer.
Key facts
- Road length: 76.2 km
- Site clearance: 105 hectares
- Cut and excavation: 710,000 m³
- Fill and embankment: 2,281,130 m³
- Cement-treated subbase: 184,404 m³ (200 mm)
- Asphalt wearing course: 50,000 m³ (1,000,000 m², 50 mm)
Clearing the corridor
Work started with site clearance across 105 hectares and topsoil stripping of 149,000 m³. Topsoil is removed because it is too soft and organic to support a road.
Earthworks
Cut and excavation in road cuttings totalled 710,000 m³. Of this, 480,000 m³ of soft material was reused as fill, 180,000 m³ of soft material went to spoil, and 50,000 m³ was rock.
Fill and embankment reached 2,281,130 m³, made up of 2,101,600 m³ of soft material and 179,530 m³ of hard material. Reusing cut material as fill reduces haulage and the need for borrow pits. Improved subgrade, in two layers (ISG 1 and ISG 2), totalled 553,212 m³.
| Earthworks activity | Executed quantity |
|---|---|
| Site clearance | 105 hectares |
| Topsoil stripping | 149,000 m³ |
| Cut and excavation | 710,000 m³ |
| – soft material reused as fill | 480,000 m³ |
| – soft material to spoil | 180,000 m³ |
| – rock | 50,000 m³ |
| Fill and embankment | 2,281,130 m³ |
| – soft material | 2,101,600 m³ |
| – hard material | 179,530 m³ |
| Improved subgrade (ISG 1 and ISG 2) | 553,212 m³ |
About two-thirds of the excavated material (480,000 of 710,000 m³) went back into the road as fill.
The pavement layers
| Pavement layer | Executed quantity |
|---|---|
| Cement-treated subbase, 200 mm | 184,404 m³ |
| Graded crushed stone base, 150 mm | 138,303 m³ |
| Prime coat | 1,083,820 m² |
| Dense bitumen macadam (DBM) base course, 75 mm | 62,865 m³ |
| Tack coat | 838,200 m² |
| Asphalt concrete wearing course, 50 mm | 50,000 m³ (1,000,000 m²) |
Why each layer matters
The cement-treated subbase adds strength and stiffness, helping the road resist deformation under heavy trucks. The crushed stone base spreads loads further before they reach the subgrade.
The prime coat seals the base, while the tack coat bonds the asphalt layers together. The DBM base course carries much of the traffic load, and the asphalt concrete wearing course provides a smooth, durable surface for road users.
Together, these layers form a pavement designed to serve as a trunk road for Niger State.
More on the Beji–Jangara–Wushishi Road
This article is part of a five-part series on the project:
- ICCO Completes 76.2 km Section III of Beji–Jangara–Wushishi Road – the scope, timeline and completion of Section III.
- On Time and On Budget: The Beji–Jangara–Wushishi Road – the contract record: on time and on budget.
- Ten Bridges and 100 Culverts on the Beji–Jangara–Wushishi Road – the ten bridges, 100 culverts and drainage.
- Road Safety and Service Ducts on Beji–Jangara–Wushishi Road – the road safety installations and HDPE service ducts.
Frequently asked questions
How much earth was moved on the road?
Cut and excavation totalled 710,000 m³, and fill and embankment reached 2,281,130 m³. Improved subgrade added 553,212 m³.
How much excavated material was reused?
Of the 710,000 m³ excavated, 480,000 m³ of soft material was reused as fill. Reusing it reduces haulage and the need for borrow pits.
What are the pavement layers?
A 200 mm cement-treated subbase, a 150 mm graded crushed stone base, a prime coat, a 75 mm DBM base course, a tack coat and a 50 mm asphalt concrete wearing course.
Why is topsoil stripped before building a road?
Topsoil is too soft and organic to support a road, so it is removed first. On this project 149,000 m³ was stripped.
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