Analysis on common diseases and treatment of highway asphalt pavement?

Since the reform and opening up, my country's expressways have gone through stages from scratch to rapid development. The take-off of the national economy has brought new opportunities and challenges to my country's highway construction. Most of the highway pavements under construction at this stage are paved with asphalt. After they are officially opened to traffic, various diseases will inevitably occur due to the increase in service life and the increase in traffic pressure. This will affect traffic operations at least, and cause traffic safety accidents at worst, which will have a negative impact on driving. causing irreparable loss of life and property. In this regard, the highway traffic management department must regularly repair and maintain problematic asphalt pavements to nip possible safety hazards in the bud.

1. Overview of common diseases of highway asphalt pavement

(1) Subsidence

Subsidence is one of the most common diseases of highway asphalt pavement at present. It is caused by insufficient compactness of the roadbed. In addition, the soil used for the roadbed is too loose, which is also an important reason for the subsidence of the road surface. When groundwater infiltrates into the foundation soil or surface water seeps into the soil, the overall stable structure of the roadbed is destroyed. Under the action of external forces (such as vehicle rolling, etc.), it is extremely easy to produce vertical settlement, causing deformation, cracking, and cracking of the road surface. Subsidence conditions. The country has also promulgated relevant standards for this, stipulating that all overall or partial subsidence of the road surface exceeding 1cm can be defined as road subsidence. Vehicles traveling on highways travel at high speeds and some of them are loaded vehicles with large actual loads. Once the vehicle sinks or the road surface suddenly subsides, resulting in major traffic accidents such as rollover or rear-end collision, it will cause great casualties and property damage. losses, and may even cause extremely negative social impacts.

(2) Potholes

In addition to subsidence, potholes are also one of the most prominent safety hazards on asphalt highway pavements at this stage. Usually, the overall or partial detachment of aggregates caused by external forces acting on asphalt pavement is called potholes. The depth of potholes is generally more than 3cm, and the area of ??potholes is also greater than 10dm2/

(3) Ruts

People will form ruts with a depth of more than 1cm due to repeated rolling over by heavy-duty vehicles over time. The striped grooves are called ruts. After a highway has been used for a certain period of time, if it is not maintained and repaired regularly, it is possible that the asphalt pavement will undergo plastic deformation due to long-term load-bearing rolling and form ruts. It not only affects the cleanliness and beauty of the road surface, but also brings potential traffic safety hazards and provides conditions for traffic accidents.

(4) Cracks

1. Transverse cracks

Transverse cracks are load-type cracks. They are mostly caused by insufficient construction technology, poor quality of building materials or moving vehicles. Transverse fracture caused by the load exceeding the actual load capacity of the road. Due to inferior building materials or substandard construction technology during construction, the actual tensile stress of the asphalt pavement surface layer will exceed the fatigue resistance of the asphalt pavement under the action of external forces, thus increasing the burden on the surface layer. If things go on like this, the surface layer will be overwhelmed and develop. fracture, forming load-type cracks.

2. Longitudinal cracks

Different from load-type cracks, the causes of longitudinal cracks can be roughly divided into two categories. One is that the asphalt joints are not properly handled during construction, leaving There is a safety hazard. After it is put into use, it is affected by factors such as repeated rolling by vehicles and penetration of rainwater, causing longitudinal cracks to appear inside the concrete. Secondly, the soil of the roadbed is loose or insufficiently tight, and under the action of natural factors or external forces, Subsidence occurs below, causing internal cracks in the concrete.

3. Network cracks

During the construction process of expressways, not all high-strength concrete and asphalt will be used to lay them. The road will contain some particles composed of gravel, earth and stone. With the passage of time and repeated rolling by vehicles, the gaps between the granular layers will expand day by day, and then the slurry phenomenon will appear. After being rolled over again by heavy trucks, block cracks or network cracks will appear on the highway pavement. This poses a hidden danger to driving safety.

(5) Bridge deck movement

Normally, the asphalt layer is laid directly on top of the concrete layer of the highway, and the friction between the two is small, making the asphalt road surface After use, it is continuously pushed by vehicles and produces longitudinal displacement, causing the bridge deck to move.

2. Effective countermeasures to deal with common diseases of highway asphalt pavement

(1) Countermeasures to deal with subsidence problems

Maintenance personnel should first find the subsidence area and use Professional tools are used to cut through the asphalt layer and water-stabilized layer laid on the road, repair the diseased layer from the source, follow the standardized construction process, and promptly clean up the waste materials or sand and other debris left in the repair layer after the repair is completed, in accordance with The asphalt proportions are re-mixed to create a coating to repair the asphalt layer, repair the water-stabilized layer and asphalt layer, compact and smooth them with a road roller, and open to traffic after the asphalt temperature drops to normal temperature.

(2) Countermeasures for repairing potholes

Maintenance personnel must first use professional cutting equipment to cut the asphalt pavement where potholes occur according to the geometric outline, and then cut the roadbed Conduct a comprehensive inspection to ensure that no safety hazards are missed. If there is indeed no problem, the roadbed should be cleaned directly, and then the asphalt mixture should be prepared and used to fill and compact the potholes with a tightness of up to 95 After the above and it is confirmed that the old and new asphalt mixtures have been completely bonded together, traffic can be resumed after the asphalt temperature drops to normal temperature.

(3) Countermeasures for dealing with rutting problems

Technical maintenance personnel must first conduct a careful inspection of the road surface where rutting occurs, determine the level of the disease, and formulate a response plan based on the severity of the disease. After the judgment is completed, the obtained data information should be classified and summarized to summarize the number and location of rutting diseases in a certain area, laying the foundation for maintenance and construction work. Then place safety warning signs at locations where construction is required to remind passing vehicles that construction is underway. Then the rutted road surface is milled, emulsified asphalt is sprayed on it, and asphalt mixture is laid, and a smooth wheel roller is used to compact the road surface to restore it to smoothness. Finally, the safety warning signs were removed and the road was opened to traffic. The asphalt mixture used to fill ruts must adopt a new proportioning method to achieve higher high-temperature stability and prevent the recurrence of ruts.

(4) Countermeasures to deal with the problem of bridge deck shifting

Once the problem of bridge deck asphalt shifting occurs, the displaced asphalt pavement must be eradicated as soon as possible, and the upper part of the concrete layer and the asphalt layer must be A rough cement layer is laid at the connecting parts to increase the contact friction between the two levels, reduce the probability of displacement, and further ensure the safety and stability of highway traffic. In addition, construction technicians can also increase the proportion of gravel particles in the asphalt mixture to increase friction. When paving asphalt, technicians should try their best to avoid segregation. They should abide by industry regulations and carry out construction operations in accordance with the professional process requirements for asphalt paving, so as to clear obstacles for highway traffic safety, effectively extend the service life of highways, and promote highway construction. industry towards healthy and long-term development.

(5) Countermeasures for dealing with highway cracks

Although there are various forms of highway cracks, there is only one solution, which is to pour hot liquid asphalt into the cracks and wait until the asphalt Complete filling after cooling. Before the formal filling of joints, technicians must use a professional high-pressure air pump to complete the work of removing foreign matter from the joints. They must clean out the tiny stones, gravel, dust or garbage trapped in the joints, and use the wind power of the air pump to make the joints clear. The body dries quickly, paving the way for grouting. After the joint filling work is completed, gravel with smaller particle size should be evenly sprinkled on the surface of the joint in time to reduce the viscosity of the asphalt and prevent it from being stuck by passing vehicles, which will greatly reduce the effect of joint filling.

3. Conclusion

In summary, economic development has brought vitality and vitality to the highway construction industry, and the improvement of living standards has made people’s demand for transportation increasingly How to meet the public's travel and transportation needs as much as possible is an important issue facing relevant departments. The development of expressways can effectively alleviate transportation pressure, facilitate people's travel, and pave the way for the country's economic development.

However, due to the increase in traffic pressure, the problem of highway pavement disease has gradually emerged, which has seriously restricted the smooth progress of transportation and is not conducive to creating a comfortable, safe and efficient driving environment. In this regard, relevant management departments must take urgent action to strengthen road inspection and management, promptly discover safety problems and solve them promptly, without leaving any safety hazards that may lead to major traffic accidents, and lay a solid foundation for social stability and economic prosperity.

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