The pavement structure layer refers to the paving layers that make up the pavement. According to its layer position and function, there are mainly surface layer, base layer and bottom base layer.

The pavement not only has to bear the wheel load, but also has to be affected by natural environmental factors. Due to the influence of traffic load and atmospheric factors on the pavement, it generally gradually weakens with depth. Therefore, the pavement is usually a multi-layer structure. Good quality materials are laid on the upper layer with greater stress, and poor quality materials are laid on the lower stress.

The lower layer of the roadbed forms a pavement structure in which materials of different specifications and requirements are used on the roadbed, and the cushion layer, base layer and surface layer are respectively laid.

The surface layer is located at the uppermost layer of the entire pavement structure. It directly bears the vertical force and horizontal force of the driving load, as well as the repeated action of the vacuum suction generated behind the car body. At the same time, it is most adversely affected by rainfall and temperature changes. It is the level that most directly reflects the performance of the road surface.

Therefore, compared with other layers, the surface layer should have higher structural strength, rigidity, high and low temperature stability, and wear-resistant, impervious to water, and its surface should also have good skid resistance and flatness. The higher the road grade and the higher the design speed, the higher the requirements for road anti-skid and smoothness.

The materials used in the construction of high-grade road surfaces mainly include asphalt concrete and cement concrete.