The materials which are used in the construction of the highway are called highway materials. Some of the materials used in the construction of the highway are soil, sand, aggregate, cement, bitumen, etc.
Highway materials are classified under the following three headings :
- Binding materials.
- Mineral materials.
- Other materials.
The materials which are used to unite or bind two or more road/highway/mineral materials are called binding materials. Binding materials are further classified as follows:
- Inorganic materials.
- Organic materials.
Inorganic materials: These materials produce a rigid bond between the particles. Example: Cement.
organic materials: These materials produce a flexible bond between the particles. Example: Bitumen.
Soil dust: These materials produce a semi-rigid or semi-flexible bond between the particles. Example: Clay.
Mineral materials used in highway construction are stone chips, bricks, rubble, blast furnace slag. They are either naturally occurring or semi-process.
These are materials other than binding and mineral materials used in the construction of highway like steel reinforcement, timber, which are classified as other materials.