There are two types of asphalt pavement surface layers constructed by the spreading method: asphalt surface treatment and asphalt penetration. Asphalt surface treatment is to use asphalt and fine mineral aggregates to lay a thin layer of pavement surface layer with a thickness of no more than 3cm. It is usually constructed by layer paving. According to the number of layers of spreading asphalt and spreading mineral aggregates, it can be divided into single-layer, double-layer and three-layer types. Single-layer and double-layer types are part of the three-layer type.
Three-layer surface treatment construction:
Clean the base layer. Before the surface treatment construction, the road base layer should be cleaned so that most of the mineral aggregates on the base layer are exposed and kept dry; if the overall strength of the base layer is insufficient, it should be reinforced first.

Spread the penetration layer (or adhesive layer) asphalt. The first layer of asphalt should be spread evenly. When it is found that there are gaps or missing edges after spreading asphalt, it should be immediately filled with workers. If there is accumulation, it should be scraped off immediately. Asphalt spreaders should be used to spray asphalt during construction, and the spreading length should be coordinated with the mineral aggregate spreading capacity. The asphalt spreading temperature should be determined according to the construction temperature and the asphalt grade. Under normal circumstances, petroleum asphalt should be 130℃～170℃, coal asphalt should be 80℃～120℃, and emulsified asphalt should be spread at room temperature.
Spread the first layer of mineral material: After spreading the main layer of asphalt, the first layer of mineral material should be spread immediately with a mineral material spreader or in the workplace. The mineral material should be spread evenly to achieve full coverage, uniform thickness, no overlapping of mineral materials, and no exposure of asphalt. If there is a shortage or excess of material in some places, it should be properly filled or cleared.
Rolling: After spreading a section of mineral material, roll it with a 60~80kN double-wheel roller. When rolling, it should be rolled from one side of the road edge to the middle of the road. It is advisable to roll 3~4 times. The speed should not exceed 2km/h at the beginning, and it can be appropriately increased later.
Spread the second layer of asphalt, spread the second layer of mineral material, roll it, then spread the third layer of asphalt, spread the third layer of mineral material, and roll it.
Initial maintenance: After the asphalt surface is treated, initial maintenance should be carried out. When oil spills are found, caulking materials with the same specifications as the last layer of mineral materials should be spread evenly on the oil spilled area; when there are too many floating mineral materials, they should be swept out of the road; when there are other damage phenomena, they should be repaired in time.
Penetration pavement construction:
Asphalt penetration pavement is a porous structure. In order to prevent the intrusion of surface water and enhance the water stability of the pavement, the top layer of its surface layer should be spread with sealing materials or a mixing layer. When the asphalt penetration layer is used as a connecting layer, the surface sealing material may not be spread. Asphalt penetration pavement is suitable for roads of level 2 and below, and its thickness should be 4 to 8 cm, but the thickness of emulsified asphalt penetration pavement should not exceed 5 cm. When the asphalt mixture surface layer of the mixing layer is added on the top of the penetration layer, the total thickness should be 6 to 10 cm, of which the thickness of the mixing layer should be 2 to 4 cm.
The construction process of asphalt penetration pavement is as follows: clean the base layer → sprinkle penetration layer or tack layer asphalt (emulsified asphalt penetration or asphalt penetration thickness is less than 5cm) → sprinkle main layer mineral material → rolling → sprinkle the first coat of asphalt → sprinkle the first coat of caulking material → rolling → sprinkle the second coat of asphalt → sprinkle the second coat of caulking material → rolling → sprinkle the third coat of asphalt → sprinkle sealing layer material → rolling → initial maintenance.