Pavement of an expressway engineering construction Technical Guidelines
Project overview A highway has a total length of 93km, subgrade width of 26m, and two-way four lane. There are 13 major bridges, 7 medium bridges, 25 small bridges, 84 passageway overpasses, 117 culverts, 5 interchanges, 19 separation overpasses, 6 toll stations, and 1 service area along the line. The earthwork quantities along the line are 15.1764 million m3. Pavement works include main line, interchange ramp pavement, pavement drainage system, curb and earth shoulder, bridge deck pavement and expansion joints. Key points of pavement engineering design The standard axle load of pavement structure design is Bzz-100, the design speed is 100km/h, and the design service life is 15 years. Among them, SBS modified asphalt was used for the first time in expressway construction in Liaoning Province. The main line pavement structure is divided into cushion, base course and surface course. The cushion filling section uses 15cm gravel, and the excavation (stone) section uses 5cm gravel leveling layer; The 37cm base course is made of cement stabilized gravel mixed with crushed gravel, which is divided into two parts: the lower base course (19cm) and the upper base course (18cm); The 15cm surface layer is composed of upper, middle and lower parts, the upper layer is 4cm 5% SBS modified asphalt concrete anti sliding layer (AK-13A), the middle layer is 5cm 3% SBS modified medium grained asphalt concrete (AC-20I), and the lower layer is coarse grained asphalt concrete (AC-25I). In order to improve the pressure resistance of the pavement and prevent early damage of the pavement, the middle and lower layers are closely graded to reduce rain and snow infiltration; The upper layer is anti sliding surface layer, and the porosity of each layer is controlled within 3-5%.
