Roads are classified based on various criteria, and each of these criteria is further classified into different types of roads. The following factors are used to categorise different types of roads:
- Construction materials
- Location & function
- Traffic volume
- Usage of road
- Traffic type
- Surface type
- Geometric elements
- Accessibility and speed
In this post, I will provide a brief overview of the various types of roads based on their construction materials.
What are the Different Types of Roads?
These are roads that are built with the available soil on the site. They are less expensive than all other types of roads. Earthen roads are intended for very light traffic.
The available soil is laid in two to three layers, and the road surface is compacted with a rammer to expel the excess voids in the soil.
A good drainage system that provides excellent performance over a longer period of time should be provided.
These roads are also known as temporary roads because they are usually laid to move construction vehicles while constructing a structure or to move army vehicles during wartime.
It is not recommended to use earthen roads during the monsoon season because the soil may wash away during the rain.
Gravel roads are the second cheapest of all road types, and they are also superior to Earthen roads.
In this type of road, a mixture of gravel and earth (local soil) is paved and compacted on the surface. Metal roads are another name for gravel roads. These roads are simple to construct and are typically found in villages.
Murram is a gravelly lateritic material formed by weathering agencies during the disintegration of igneous rocks. Murram roads are those that are built with Murram as the primary material. Murram has a higher density than gravel and provides a better surface finish and compaction than the other two types of roads.
Kankar is a type of impure limestone. Kankar roads are built where there is a sufficient supply of lime. Kankar road is a low-quality road, but it is better than earthen and gravel roads.
Water Bound Macadam Roads [WBM]: Crushed stone aggregate is used in the base course of Water Bound Macadam (WBM) roads. After sprinkling water on the surface, the aggregates are spread and rolled. WBM roads outperform earthen, gravel, murrum, and kankar roads in terms of performance.
WBM roads are built in layers of about 10cm thickness. They are extremely rough and may disintegrate immediately when subjected to traffic.
Bituminous is a black viscous and adhesive material that forms during the distillation of gasoline. Bituminous roads are widely used throughout the world because they are simple to construct and provide a smooth, even surface finish. The thickness of the bitumen road is determined by the subgrade soil at the site. It is always recommended that bitumen roads be laid in two layers.
These road types are low-cost and appropriate for driving conditions.
Concrete roads are those that are constructed using cement concrete as a base material. These are the most expensive roads of all types. This type of road is recommended in areas with high traffic volumes, and it takes longer to build concrete roads because the concrete requires proper curing. A concrete road has an average life of 40 years, whereas a bituminous road has an average life of 3 years.