Road construction vocabulary

Roads are made up of four layers. These include: 

parts of a road

Layers of road construction

  • Sub-grade: Native soil underneath a road.
  • Sub-base: Layer of aggregate materials on top of the sub-grade
  • Base (also base course): Layer of material under the surface course.
  • Surface (also surface course): The upper layer of the road.

The surface can consist of asphalt, concrete, cobblestones, tiles or earth materials. Asphalt and concrete are the most common surface materials.
  • Asphalt: Black or brown sticky substance, mixed with crushed stone, sand or gravel, which is used for construction of road surfaces.
  • Concrete: Building material created by mixing together cement, sand, gravel and water.
  • Cobblestone: Rounded stone used to make the surfaces of roads.
  • Tile: Concrete or baked clay of various shapes and colors, used for covering walls, roofs or surfaces.
  • Earth materials: Soil, sand, gravel or granular products.

Road drainage

  • Gutter: Channel at the side of a road to collect rainwater and carry it away from the roadway.
  • Ditch: Long hole dug at the side of a road to channel water.
  • Culvert: Tunnel that channels water under the roadway from one side to the other.

Road surface marking

  • Yellow lines: Lane of traffic moving in opposite directions.
  • White lines: Lane of traffic moving in the same direction.
  • Solid lines: Unsafe to cross the line
  • Broken lines: Safe to cross the line if the way is clear.

Road machinery

  • Grader: Vehicle with a long blade used for grading surface.
  • Roller: Heavy vehicle used to make surface flat by compacting soil, gravel, asphalt, or concrete.
  • Paver: Vehicle used to lay asphalt or concrete on surface.

Road surface

Sentence examples:

Culverts help control water flow.
The ditches play important roles in agriculture.
Graders are often used to remove snow.
Cobblestones date back to ancient times.