Pavement classification

1. The surface materials of the advanced surface course are cement concrete, asphalt concrete, factory-mixed asphalt macadam and clean stone, and the applicable highway grades are expressway, Grade I and Grade II.

2. The surface materials of the secondary high-grade surface course are asphalt permeable macadam, road-mixed asphalt macadam, asphalt surface treatment and semi-clean block stone, and the applicable highway grades are expressway, first-class highway and second-class highway.

3. For the middle surface course, the surface course material is granular materials such as mud bound or graded macadam, hydraulic bound macadam and irregular block stone, and the applicable highway grades are high-speed, first-class and second-class highways.

4. For the low-grade surface course, the surface course material type is various granular materials or local material improved soil, such as slag soil, crushed stone soil and gravel soil. The applicable highway grades are high-speed, first-class and second-class highways.

Extended data

Classification of pavement grade structure layers:

1. surface course: the surface course is located at the top of the whole pavement structure. It directly bears the repeated action of vertical force, horizontal force and vacuum suction behind the car body, and is most adversely affected by rainfall and temperature change, which is the level that directly reflects the pavement performance.

2. Base course: the base course is located below the surface course and above the cushion or subgrade. The base mainly bears the wheel vertical force transmitted by the surface layer and spreads to the cushion layer and soil foundation, and may also be eroded by surface seepage and groundwater. Therefore, materials with high strength, high rigidity and sufficient water stability should be selected.

3. Cushion: Not all pavement structures need cushion. Cushion should be set only when the soil foundation is in a bad state, such as wet zone, wet soft soil foundation, frost heave soil foundation in northern China, etc. In order to eliminate the free water stranded in the pavement and subgrade and ensure that the pavement structure is in a dry or moderately wet state.

Baidu encyclopedia-pavement