Section I: classification and classification of urban roads

Urban roads are divided into Expressway 、 The main road 、 Secondary road And Access Rd Four levels ;

1. Expressway , Also known as urban expressway , Fully serve the traffic function , It is to solve the problem of large urban capacity 、 City distance 、 The main road of rapid traffic ;
2. The main road Mainly traffic function , It is a trunk road connecting the main districts of the city , It is the main framework of the urban road network ;
3. Secondary road It is a regional trunk road in the city , Serve for regional traffic distribution , It also has service functions , Combined with trunk roads to form a trunk road network ;
4. Access Rd It is a secondary trunk road and residential area 、 industrial area 、 Connecting lines of internal roads such as traffic facilities , It is to solve local traffic problems , Focus on service functions .

The road surface is divided into Asphalt pavement 、 Cement concrete pavement and Block pavement Three broad categories ;

• Asphalt pavement The type of surface course includes asphalt mixture 、 Asphalt penetration and asphalt surface treatment . Asphalt mixture is applicable to all traffic grade pavement , Asphalt penetration type and asphalt surface treatment are applicable to 、 Light traffic road .
• Cement concrete pavement The type of surface course includes ordinary concrete 、 reinforced concrete 、 Continuously graded concrete and steel fiber concrete , It is applicable to roads of various grades .
• Block pavement Applicable to branch 、 square 、 The parking lot 、 Sidewalk 、 Pedestrian street .

Flexible pavement ： The deflection deformation under load is large 、 Low flexural tensile strength , Cumulative deformation under repeated load , Its failure depends on the ultimate vertical deformation and bending tensile strain . Flexible pavement is mainly represented by various asphalt pavement , Including asphalt concrete surface course 、 Asphalt macadam surface course 、 Asphalt penetration crusher （ gravel ） Stone surface course .
Rigid pavement ： Under the action of driving load, the plate will act , High flexural tensile strength , The deflection deformation is very small , Showing greater rigidity , Its failure depends on the ultimate flexural tensile strength , Rigid pavement is mainly represented by cement concrete pavement .