Which layer contributes significantly to the structural strength of the pavement?

The base course plays a crucial role in contributing to the structural strength of pavement. It is situated directly beneath the surface course and is designed to distribute loads from the pavement surface to the underlying layers. The base course typically consists of granular materials that provide adequate support and stability to withstand traffic loads and environmental conditions.

This layer acts as a buffer, helping to absorb and mitigate stresses that would otherwise be transferred to the subgrade, the layer beneath the base course. Properly designed and constructed base courses enhance the overall durability and longevity of the pavement structure. The material composition and thickness of the base course are critical factors in ensuring that it can effectively carry the anticipated traffic loads, which in turn minimizes deformation and potential failure of the pavement.

In contrast, while the surface course is essential for providing a safe riding surface and protecting the underlying layers from weather and wear, it does not bear the primary load. The intermediate course could serve specific purposes in certain pavement designs but generally works in conjunction with the base course rather than acting as the principal strength contributor. The subgrade, while foundational, is not engineered to provide structural strength; its primary role is to support the layers above it.