On-site management measures for road surface damage in highway projects?

On-site management measures for pavement damage in highway projects are very important. The harm caused by pavement damage can be large or small. When managing, it is necessary to try not to affect traffic. Zhongda Consulting would like to introduce to you the on-site management measures for road surface damage in highway projects.

1. Analysis of the causes of highway pavement damage

(1) Impact of road water sources

Due to the fact that mountains and rivers are arranged in series and alternately distributed, the terrain is undulating. , forming a complex geographical environment, making highways prone to features such as many tunnels, many bridges, many downhill slopes, and many curves. Many driving vehicles are equipped with brake sprinkler systems. Coupled with the abundant precipitation in some areas, a large amount of water enters the pavement structure layer and subgrade, making the pavement structure and subgrade in a wet or excessively wet state. Under the action of driving loads, Resulting in early damage to the highway pavement.

(2) Highway pavement cracks

First, block cracks: irregular large-grid network cracks appear on the road surface, and the spacing between these cracks is mostly small. After such cracks appear on the asphalt pavement, when it encounters rainy weather, the rainwater gradually penetrates along the cracks into the base layer, making the path softer and softer, which in turn causes its bearing capacity to become lower and lower, ultimately leading to more damage to the pavement. serious. For this reason, when encountering such cracks, corresponding repair measures must be taken promptly to avoid serious consequences.

Secondly, longitudinal cracks: There are many main factors leading to longitudinal cracks on highway pavements, which can be summarized into four aspects: First, due to uneven solidity of the roadbed, for example: half-filled roadbed Longitudinal cracks usually appear in the semi-excavated part; secondly, when paving the asphalt surface layer in sections, if the joint between the two sections is not handled properly, it is very easy to be unable to withstand the load after passing through and longitudinal cracks will occur; thirdly, , the groundwater level dropped, causing the roadbed to be affected. If a section of highway is under construction, due to the high groundwater level, a large space is reserved for it. However, as the climate changes, the climate becomes dry or the rainfall gradually decreases, the groundwater level decreases. Changes in the groundwater level affect the consolidation of weak soil layers and other aquifers, causing the foundation to sink. At the same time, due to uneven path settlement, the road surface is damaged; fourth, its weight exceeds the ability of the road surface. tolerance range. Long-term exposure to overloaded vehicles may cause damage to the wheel tracks. Secondly, transverse cracks: Transverse cracks are a common type of damage to asphalt surface layers. According to relevant survey data, it is understood that basically every asphalt pavement highway will have transverse cracks to varying degrees. The factors that lead to the occurrence of this kind of cracks are mainly divided into non-loading cracks and loading cracks. The occurrence of load-induced cracks is mainly due to the fact that the actual conditions are not taken into account when designing the pavement, resulting in improper design or construction quality that does not meet the regulations, or long-term operation of overweight vehicles, which makes the semi-rigid base or asphalt surface The internal shear stress and tensile stress of the layer will eventually cause cracks due to long-term fatigue use. Non-load cracks are the main form of transverse cracks, which can be divided into two types: base reflective cracks and asphalt surface temperature shrinkage cracks. Among them, asphalt surface layer temperature shrinkage cracks, because asphalt is a viscoelastic material that is very sensitive to temperature changes, when the temperature changes, the asphalt mixture will also change with the temperature change, for example: when the temperature drops , the asphalt mixture will also become hard, brittle, and shrink. When the tensile strength of the asphalt concrete cannot withstand the shrinkage stress, the asphalt pavement will crack, and the cracks will develop deeper and deeper, resulting in transverse cracks that are wide at the top and narrow at the bottom. In areas with cold temperatures, when freezing occurs in winter, the transverse cracks of asphalt pavement mainly manifest in two situations: first, when entering winter, due to the sharp drop in temperature, the asphalt surface layer changes and shrinkage cracks occur; second, Changes in temperature cause the temperature stress of the asphalt surface layer to undergo great changes. In addition, the repeated action of temperature stress causes cracks in the asphalt surface layer due to temperature changes.

Reflective cracks in the base layer, on the one hand, occur when the base layer is formed. They are mainly caused by the shrinkage of the base material due to water loss and regular cracks; on the other hand, they are mainly caused by changes in the base material due to temperature changes. , mainly due to shrinkage caused by temperature drop, resulting in cracking. Both of the above situations cause the asphalt surface layer to bear excessive tensile force due to shrinkage and deformation. When it cannot bear the excessive tensile force, cracks will eventually appear at the bottom of the asphalt surface layer, and then displacement will occur. As the humidity and temperature change, Changes and the long-term effects of overload weighing cause cracks to extend from the bottom to the road surface, forming transverse cracks in the asphalt pavement.

Finally, cracks: The main reason for cracks is due to uneven base quality and poor cushion quality, which are also the main factors causing damage to highway pavement. The base layer serves as a supporting force to ensure that the cement concrete pavement slab is always uniform and plays an important role in preventing misalignment and mud. It can be said to be an important structure that determines the service life of the highway. During the use of highways, it is common for cracks to appear on the road surface, and cracks are usually accompanied by slurry. For example, when subsidence and cracking occur, they are not treated in time. After being washed and soaked by rainwater, potholes appear at these cracks, which in turn causes damage to the road surface. For this reason, it is important to repair the cracked road surface in time. Important way to avoid damaging extensions. The main reasons for cracks are: first, the quality of the base layer is poor. Since the overall quality of the fly ash gravel semi-rigid base is closely related to many factors such as the materials used, mixing, curing and paving, problems in any link may lead to a decrease in its overall strength, causing problems due to base quality problems. The cracking of the asphalt surface layer, coupled with the long-term rainwater penetration, gradually softens the surface of the base layer. When it cannot bear the driving load, the slurry is gradually pressed to the surface through the cracks in the surface layer and slurry will occur. With this phenomenon As the road surface evolves, the base layer will gradually be hollowed out, causing the road surface to sink and crack, eventually turning into potholes. The main construction factor that leads to this phenomenon is that during the construction process, poor construction quality causes cracks, especially the compaction of each structural layer plays a key role. The better the compaction, the less likely it is to avoid the occurrence of cracks. the higher. Drainage is also the main factor related to the occurrence of cracks. At the same time, the better the surface joint treatment effect, the better the effect. These are important factors to ensure cracks; secondly, the car is overloaded. As the traffic volume in our country is getting higher and higher, and highways, as important transportation lines, bear huge traffic volume, and the increase in traffic volume makes the road surface load very high. In the case of long-term overloading, the road surface cannot bear the load. And cracks appear; third, other factors. Due to the aging of the pavement caused by asphalt concrete being used for too long or shrinking, the pavement will crack and eventually develop into network cracks. (3) Maintenance management In the current maintenance operation, the compaction equipment is not matched, and the three processes of initial pressure, re-pressure, and final pressure are difficult to realize in maintenance practice. It is difficult to achieve the necessary compaction degree of the compacted mixture. Lack of actual equipment conditions is a major cause of road repair damage. At the same time, due to the small construction area during curing, it is difficult to compact and compact, the void ratio is larger, and surface water can easily seep down. When repairing pavement defects, the mixing and compaction of asphalt concrete are difficult to meet the requirements, so the phenomenon of damage before repairing and later after repairing often occurs.

2. Construction technical measures to solve highway pavement damage

(1) Do a good job in on-site construction management

For highway pavement damage, there are also reasons Improper construction management leads to pavement damage. Therefore, we cannot ignore the importance of management for highway pavement construction. As construction technicians and supervisors, we need to do a good job in on-site construction control and management from the beginning of highway construction to pavement construction. Only in this way can it be possible to minimize the probability of damage to the construction pavement, and only in this way can we It can ensure that the quality of highway pavement is not affected in any way.

(2) Specific construction measures - concrete slab grouting treatment

First, the choice of grouting plates: When grouting the original concrete slab, it is often necessary to combine the plates The difficulty of cracks and grouting plate sections, combined with whether the original concrete slab needs grouting, is used to determine whether to grout the original concrete slab or to dismantle it; secondly, the layout of the drilling holes. The specific drilling locations will be arranged based on the specific conditions of cracks and subsidence of the original concrete panel, but it must be ensured that there are at least 5 drilling holes for each panel. In addition, when determining the location of the drill hole, it must also be ensured that it is more than 30 cm away from the edge of the crack and the free edge of the plate. Third, grouting material requirements and mortar ratio. Combined with the characteristics of the grouting construction process, it ensures that the grouting mixture has good fluidity and can be transported to the bottom of the slab; it has very good strength after forming. For this reason, it is very important to select the materials used for grouting, and the mix ratio also has a very critical effect.

(3) Specific construction measures - pavement damage maintenance

1. Maintenance of pavement cracks

Under the simultaneous action of driving load and rainwater Grouting occurs at cracks, cement-stabilized gravel falls off and becomes loose due to water, the pavement structure has insufficient bearing capacity, edge gnawing occurs, and may develop into network cracks or pits, subsidence, etc. If there are many cracks, emulsified asphalt slurry sealing layer should be used. For network cracks caused by insufficient strength of the base layer, the asphalt concrete pavement should be milled to treat the base layer, and then the asphalt concrete surface layer should be paved; secondly, grouting should be done during preventive maintenance.

2. Maintenance of pavement deformation

Subsidence mainly refers to the phenomenon of local depressions on the surface of the highway pavement. Generally speaking, it is due to irregularities in the roadbed. It is caused by uniform settlement, or it is caused by the failure to compact the backfill after excavation. As the structure of the highway pavement is damaged, if it is not repaired in time, it can also lead to the continued development of pavement diseases. In maintenance, generally speaking, it is necessary to deal with the subsidence of the subsidence first. After the settlement becomes stable, the subsidence can be milled with a milling machine and paved in layers to ensure that the road surface can be restored to a smooth state. .

3. Conclusion

For the damage of highway pavement, we need to take into account the actual situation on site and adopt different methods to carry out targeted repair plans, know how to make use of strengths and avoid weaknesses, and rationally use road damage Only in this way can the remedial plan save costs to the maximum extent while ensuring the smooth repair, and can also complete the repair as soon as possible to ensure that highway operations will not be greatly affected.

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