First, the meaning of preventive maintenance of asphalt concrete pavement structure is introduced, and the current research, development and application status of preventive maintenance of asphalt concrete pavement structure at home and abroad are summarized. The commonly used construction methods of preventive maintenance of asphalt concrete pavement structure are introduced, and the post-treatment and other key issues of preventive maintenance of asphalt concrete pavement structure are analyzed and summarized, and the future development trend is prospected.

Preventive maintenance
Preventive maintenance refers to a maintenance method implemented when the pavement structure has not yet been damaged. It improves the operating status of the pavement structure and delays the damage of the asphalt pavement without increasing the structural bearing capacity. Compared with traditional maintenance methods, preventive maintenance is more proactive and requires reasonable planning to achieve the desired effect.
Since 2006, the former Ministry of Transport has promoted the use of preventive maintenance nationwide. Over the past decade, my country's highway engineering maintenance staff have begun to accept and use preventive maintenance, and the technology of preventive maintenance has become more and more mature. During the "Twelfth Five-Year Plan" period, the proportion of preventive maintenance in my country's maintenance projects increased by five percentage points each year, and achieved remarkable road performance results. However, at this stage, preventive maintenance work is not yet mature, and there are still many areas to be studied. Only through a lot of accumulation and research can preventive maintenance technology become more mature and achieve better use results.
Main methods of preventive maintenance
In my country's highway engineering maintenance, according to the scale and difficulty of the maintenance project, the maintenance project is divided into: maintenance, minor repairs, medium repairs, major repairs and renovation, but there is no separate category of preventive maintenance, which will greatly affect the implementation of preventive maintenance projects. Therefore, in the future maintenance development, preventive maintenance should be included in the maintenance scope. At present, the construction methods commonly used at home and abroad for preventive maintenance of asphalt concrete pavement structure include sealing, slurry sealing micro-surfacing, fog sealing and crushed stone sealing.
Sealing mainly includes two forms: grouting and grouting. Grouting is to apply engineering glue for sealing directly at the location where cracks occur on the road surface. Since the cracks are sealed with glue, the size of the cracks cannot be too large. This method is only suitable for diseases with mild diseases and small crack widths. When repairing, a gel with good viscoelasticity and high temperature stability should be used to treat cracks, and cracks that appear need to be treated in time. Sealing refers to heating the damaged part of the road surface and cutting it open, and then using sealant to seal the seams in the grooves.
Slurry sealing micro-surface technology refers to the method of spreading a mixed material formed by mixing a certain grade of stone, emulsified asphalt, water, and filler on the road surface using a slurry sealer. This method can effectively improve the road performance of the road surface, but it is not suitable for the treatment of road surface diseases with large-scale diseases.
Mist sealing technology uses an asphalt spreader to spray highly permeable modified asphalt on the road surface to form a road surface waterproof layer. The newly formed road surface waterproof layer can improve the water resistance of the road surface and effectively prevent moisture from further damaging the internal structure.
Chip seal technology uses an automatic sprayer to apply an appropriate amount of asphalt on the road surface, then spreads gravel of a certain particle size on the asphalt, and finally uses a tire roller to roll it into shape. The road surface treated with chip seal technology has greatly improved its anti-skid performance and water resistance.