1. Phenomenon:

The surface of the asphalt mixture is relatively smooth after manual paving, leveling, and rolling. When traffic is opened, the road surface appears wavy or has "dish" pits or "pimples" pits.

2. Reason analysis:

(1) The flatness of the bottom layer is poor, because all kinds of asphalt mixtures have certain compaction coefficients. After paving, the surface is flattened. Because the bottom layer is uneven, the paving is false. The thickness may be thin or thick. After rolling, if the thin part has less settlement, it will be higher. If the thick part has more settlement, it will be lower. The surface flatness will be poor.

(2) The paving method is improper. In a virtual pavement layer of equal thickness, the asphalt mixture is compacted due to high throwing of a shovel during paving, or the impact force during transportation and unloading, or people , the car trampled and rolled over the empty mixture, and then rolled over it, resulting in inconsistency between the actual and actual conditions. The virtual part is lower, the real part is higher, and the flatness is poor.

(3) The bottom of the material is not completely removed, the asphalt mixture is dumped directly on the bottom layer, and the bottom of the material bonded to the bottom layer is not completely removed. Or just spread the day’s leftovers randomly on the bottom floor. Serves as part of the paving material. But it has been compacted and condensed, greatly reducing the compaction factor. When the new material is replenished, flattened and compacted, local protrusions, lumps, and unevenness are formed.

3. Hazards:

(1) Pavement smoothness is the main function of road engineering. If the road is uneven, it will reduce driving speed, increase driving turbulence, increase impact force, damage vehicle parts, reduce comfort, reduce safety, and reduce economic and social benefits.

(2) The more uneven the road surface is, the greater the impact of the vehicle will be, and the more serious the damage will be to the road, which will greatly reduce the investment efficiency of road engineering construction.

4． Governance methods:

(1) First of all, the problem of flatness of the bottom layer must be solved. The bottom layer referred to here refers to it in general. If the asphalt mixture surface layer is laid in three layers, then the bottom layer of the surface layer is the mid-surface layer (black gravel or coarse-graded asphalt concrete), the bottom layer of the mid-surface layer is the bottom layer (asphalt gravel), and the bottom layer of the bottom layer is It is the road base. The bottom layer of the base layer is the road bed (soil road bed), and the smoothness of each layer is crucial to the smoothness of the previous layer. Therefore, the requirements for each layer of the pavement must be strictly controlled and carefully inspected in accordance with the quality inspection and assessment standards. Especially on the basis of ensuring the density and vertical and horizontal elevation of each layer, the flatness is raised to a higher standard and controlled, and finally the high quality of the surface layer flatness can be ensured. From the perspective of construction technology management, the five-point-five-line method should be used to encrypt checkpoints for the longitudinal and transverse elevations of the bottom layer (see Figure 1-4-6); in terms of technical operations, detailed repairs and trimming should be carried out in accordance with the requirements of elevation control; in terms of machine tools In terms of equipment, we actively create conditions and use graders to trim the flatness of the road bed and base layer.

(2) A paver should be used for paving the surface layer, and the elevation reference lines on both sides of each paving should be accurately positioned. The operator should control the screed to ensure high stability; small areas or unconditional When using a paver, pave in strict accordance with the methods stipulated in the operating procedures, that is, use the shovel buckling method. The spade is not allowed to be raised. The spades must be overlapped. When buckling the spade, it is required to scrape back slightly with the spade head to make the thickness uniform. consistent. When using trolleys and loaders to transport materials, use a hot shovel to loosen the solid bottom part of the material and then spread it flat to ensure that the material is consistent everywhere. During the leveling process, you must not step on the uncompacted virtual pavement. It is necessary to go back and flatten once to survive. If you find any unevenness again, you can prepare a special long scraper to find and flatten it.

(3) The asphalt mixture should be unloaded on the iron plate and cannot be dumped directly on the paving base layer. If it is to be disposed on the bottom layer, it must be cleaned cleanly. The remaining cold material cannot be laid directly on the bottom layer to serve as part of the layer thickness. It should be heated and used for other purposes.