What is the relationship between the base course and the surface course in road construction?

In road construction, the base course serves as a foundational layer, providing structural support and stability for the road. It is typically constructed using aggregate materials that help distribute loads and enhance the road's overall durability. The surface course, on the other hand, is the top layer that comes into direct contact with traffic and environmental elements. This layer is designed to provide a smooth riding surface and can be composed of asphalt, concrete, or other materials that improve traction and resist weathering.

Understanding the structure of a road is crucial, and the base course is specifically placed beneath the surface course to fulfill its role in load distribution and protection against subgrade failure. This hierarchical relationship is fundamental in ensuring the longevity of the road, as the surface course relies on the strength and stability provided by the base course below it.