Solver Engineering Consultancy PLC

1. Sub-Grade (150 – 300 mm):-

The bottommost layer, typically made of compacted soil or natural ground. It provides the foundation for the road structure.

2. Sub-Base (100 – 300 mm):-

A layer above the sub-grade, often made of granular material. It helps distribute loads and improves drainage.

3. Base Course (100 – 300 mm):-

Provides structural support to the road. It's usually made of crushed stone or other granular materials.

4. Binder Course (50 – 100 mm):-

A layer of asphalt mix that provides additional strength and helps bind the surface course to the base.

5. Surface Course (25-50 mm):-

The topmost layer of the road, made of asphalt or other surfacing material. It's designed for direct traffic interaction, providing a smooth and durable surface.

6. Tack Coat:-

A thin layer of bituminous material applied between layers (like between the binder course and surface course) to ensure bonding.

7. Seal Coat:-

A thin layer applied on top of the surface course to protect the road from water ingress and improve surface texture.