What is a typical layer sequence in asphalt pavement structure?

In a typical asphalt pavement structure, the correct layer sequence consists of the base layer, binder layer, and surface layer. This order is essential for the performance and durability of the pavement.

The base layer serves as the foundational support that distributes loads to the subgrade beneath it. It typically consists of granular materials that can provide strength and stability to the overall structure. The binder layer, situated above the base, provides additional structural integrity and is usually made of a thicker asphalt mix than the surface layer. This layer helps to bind the aggregate particles together and contributes to the overall strength of the pavement.

Finally, the surface layer, often referred to as the wearing course, is the topmost layer that directly interacts with traffic and environmental factors. This layer is designed to resist wear, provide skid resistance, and protect the underlying layers from water infiltration and weathering.

The arrangement is crucial because having the layers in the proper order maximizes load-bearing capacity, minimizes deformation, and extends the lifespan of the pavement. Each layer serves a specific function that contributes to the overall effectiveness and longevity of the asphalt pavement structure.