Preventive maintenance can prevent pavement diseases and has become a very important aspect of road maintenance. It slows down the deterioration of pavement performance, extends the service life of the pavement, improves the service efficiency of the pavement, and saves maintenance and repair funds. It is usually used for situations that have not yet occurred. Pavement that is damaged or has only minor disease.
From the perspective of preventive maintenance of asphalt pavement, compared with other technologies, synchronous gravel sealing technology does not put forward higher requirements for construction conditions. However, in order to improve maintenance performance, it is necessary to give full play to the advantages of this new technology. Advantages still require certain conditions. First of all, it is necessary to diagnose the road surface damage and clarify the key issues that will be repaired; fully consider the quality standards of asphalt binder and aggregate, such as its wettability, adhesion, wear resistance, pressure resistance, etc.; Carry out paving operations within the scope allowed by technical specifications; correctly and reasonably select materials, determine grading, and operate paving equipment correctly. Synchronous gravel sealing construction technology:

(1) Commonly used structures: Intermittent gradation structures are commonly used, and there are strict requirements on the particle size range of the stone used for the gravel seal, that is, stones of equal particle size are ideal. Taking into account the difficulty of stone processing and the different requirements for anti-skid performance of the road surface, there are five grades, including 2 to 4mm, 4 to 6mm, 6 to 10mm, 8 to 12mm, and 10 to 14mm. The more commonly used particle size range is 4 to 6mm. , 6 to 10mm, and 8 to 12mm and 10 to 14mm are mainly used for the lower layer or middle layer of transitional pavement on low-grade highways.
(2) Determine the particle size range of the stone based on the road surface smoothness and anti-skid performance requirements. Generally, a gravel seal layer can be used for road protection. If the road smoothness is poor, stones of suitable particle size can be used as the lower seal layer for leveling, and then the upper seal layer can be applied. When the gravel seal layer is used as a low-grade highway pavement, it must be 2 or 3 layers. The particle sizes of the stones in each layer should be matched with each other to produce an embedding effect. Generally, the principle of thicker at the bottom and finer at the top is followed;
(3) Before sealing, the original road surface must be carefully cleaned. During the operation, a sufficient number of rubber-tired road rollers should be ensured so that the rolling and positioning process can be completed in time before the asphalt temperature drops or after the emulsified asphalt is demulsified. In addition, it can be opened to traffic after sealing, but the speed of the vehicle should be limited in the initial stage, and the traffic can be fully opened after 2 hours to prevent the splashing of stones caused by fast driving;
(4) When using modified asphalt as a binder, in order to ensure a uniform and equal thickness of asphalt film formed by mist spraying, the temperature of the asphalt must be within the range of 160°C to 170°C;
(5) The height of the injector nozzle of the synchronous gravel sealing truck is different, and the thickness of the asphalt film formed will be different (because the overlap of the fan-shaped mist asphalt sprayed by each nozzle is different), the thickness of the asphalt film can be made to meet the requirements by adjusting the height of the nozzle. Require;
(6) The synchronous gravel sealing truck should drive evenly at a suitable speed. Under this premise, the spreading rate of the stone and the binding material must match;
(7) The condition for use of the gravel seal layer as the surface layer or wearing layer is that the smoothness and strength of the original road surface meet the requirements.