Asphalt pavement has the advantages of high flatness, comfortable driving and low noise, but its porosity is large and its waterproof and impermeability is limited.Continuous rainfall in rainy season, short-term rainstorm, road ponding immersion, rainwater scouring and infiltration are easy to cause road cracks, pits, looseness, subsidence, water damage and other diseases, which not only reduce road traffic comfort, but also destroy subgrade structure, shorten road service life, and cause road safety hazards in serious cases.Therefore, it is the core measures to ensure the road integrity and traffic safety to do a good job in the normalization and fine maintenance of asphalt pavement in rainy season, adhere to the principles of prevention first, inspection in place, timely disposal and long-term protection.Combined with highway maintenance technical specifications, this paper combs the comprehensive maintenance methods of asphalt pavement in rainy season in detail.
Preventive maintenance before rain: build up waterproof line of pavement
Preventive maintenance before rainy season is the key to prevent road water damage, which can reduce the erosion of rainwater to road surface and subgrade from the root, focusing on drainage dredging, disease pretreatment and road surface protection.
Fully dredge the drainage system to eliminate hidden dangers of ponding
Ponding is the primary factor inducing asphalt pavement diseases. Rainwater retention for a long time will penetrate into the base through pores and fine cracks of the pavement, resulting in subgrade softening, bearing capacity reduction, and then cause pavement subsidence and cracking.Maintenance personnel shall conduct all-round inspection and cleaning of drainage facilities of the whole section in advance, thoroughly dredge road drainage gaps, shoulder drainage ditches, side ditches, culverts and rainwater wellheads, remove fallen leaves, sediment, gravel, garbage and other deposited sundries, so as to ensure smooth drainage section and smooth water flow.At the same time, repair damaged and collapsed drainage structures, repair cracked and fallen ditch walls, ensure that rainwater can be quickly drained during rainfall, without ponding, overflow and backflow, and fundamentally avoid long-term soaking of pavement subgrade by rainwater.
Pretreatment of early pavement diseases
Rainwater in rainy season will quickly enlarge minor road diseases, fine cracks, looseness, peeling and other small hidden dangers, which will rapidly expand into large pits and large area network cracks after being washed and soaked by rain.Before rain, it is necessary to carry out full coverage inspection on the road surface, accurately mark all kinds of disease points and timely dispose of them.For fine cracks of 3- 5mm, special sealing tape shall be used for sealing treatment; medium cracks of 5- 15mm shall be filled with emulsified asphalt and modified emulsified asphalt; wide cracks with width greater than 15mm shall be filled with hot asphalt after grooving and cleaning, so as to prevent rainwater infiltration along cracks.For the slightly loose and peeling areas of the road surface, the loose aggregate shall be cleaned in time, the viscous emulsified asphalt shall be painted, and the surface layer shall be sealed and protected to prevent the disease from spreading continuously in rainy season.
Strengthen the overall waterproof protection of the pavement
For old asphalt pavement with large porosity and aging surface layer, preventive waterproof maintenance can be carried out before rainy season.Emulsified asphalt slurry sealing layer, thin layer covering and other processes are adopted to seal the whole pavement, fill the fine pores of the pavement, form a dense waterproof protective layer, and improve the overall waterproof, impermeability and scour resistance of the pavement.At the same time, check the integrity of shoulder and slope, fill potholes on shoulder in time, compact loose soil, trim slope, and avoid road edge void and collapse caused by rain washing shoulder.
Dynamic patrol in rain: real-time control of traffic and diseases
Rainfall is the peak period for road diseases to break out and hidden dangers to escalate. It is necessary to implement regular dynamic inspections to deal with unexpected problems in a timely manner, ensure road traffic safety, and curb the deterioration of diseases.
In light rain and moderate rain weather, special personnel shall be arranged to patrol the road sections normally, focusing on low-lying road sections, curves, ramps, intersections and other points prone to ponding, timely cleaning up sundries and silt washed and accumulated by rainwater, dredging temporarily blocked drainage outlets, and preventing local ponding from intensifying.In rainstorm weather, the patrol frequency shall be increased, and the dangerous conditions such as sudden pit groove on road surface, water leakage on road surface, subgrade seepage and slope collapse shall be mainly investigated. The damaged points shall be marked in time, and temporary enclosure warning shall be given to remind passing vehicles to avoid, so as to avoid vehicle rolling and expanding diseases.
At the same time, the traffic state of roads shall be strictly controlled. In extreme rainstorm weather, temporary current limiting and closed control measures shall be taken in time for sections with excessive ponding and large soft road surface, and heavy vehicles shall be prohibited from passing through.Heavy vehicles rolling soaked in water soft road surface, will greatly aggravate the deformation of the road surface, subsidence, resulting in irreversible structural damage.
Emergency repair after rain: rapid disposal of various road diseases
After the rainfall ends and the road area water is drained, it is necessary to carry out a comprehensive road condition inspection as soon as possible to quickly deal with diseases derived from the rain. Follow the principle of "repair small diseases on the same day, and quickly control major diseases" to avoid the accumulation of diseases. Permanent hot-mix asphalt repair is strictly prohibited when the moisture of pavement is not completely volatilized after rain, and emergency treatment technology is preferred.
Emergency repair of pit and groove diseases
Pit is the most common asphalt pavement disease in rainy season, which is formed by rainwater infiltrating into the pores of mixture and aggregate falling off caused by vehicle rolling and suction. For small pits after rain, asphalt cold repair mixture is used for emergency repair, without heating, weather and road humidity restrictions, and can be quickly formed and opened to traffic. Construction shall be carried out in strict accordance with standardized procedures: marking and cutting the edge of pit groove, thoroughly cleaning the accumulated water, silt and loose aggregate in the groove, evenly painting adhesive layer oil, paving cold repair materials in layers, tamping and compacting, so as to ensure that the repair area is closely connected with the original pavement, smooth and free of drop. After the weather is fine and the road surface is completely dry, the hot mix asphalt mixture can be used to redo permanent repair according to the road condition to improve the repair durability.
Secondary treatment of cracks and loose diseases
After rain, recheck the sealing and filling points before rain, clean up the sealing materials washed off by rain, clean up the accumulated water and sundries inside the cracks again, fill the cracks for sealing for the second time after the cracks are dried, and prevent the continuous infiltration of rain water. For loose, pockmarked and peeling areas of pavement surface after rain, thoroughly clean off aggregates, spray emulsified asphalt to bond and seal the surface layer, and prevent the loose area from expanding continuously. For slight rutting and packing after rain, level the road surface in time, compact and repair, so as to ensure smooth driving.
Investigation and repair of subgrade hidden dangers
After rainstorm, focus on checking subgrade condition, timely find out depth and scope of hidden diseases such as local settlement of pavement, subgrade seepage, edge void, etc., clean soft base soil, backfill graded aggregate layer by layer and compact, and then redo asphalt pavement, so as to thoroughly solve hidden dangers of subgrade ponding and softening and avoid repeated damage in later period. At the same time, clean up slope siltation, repair small collapse points, and stabilize road auxiliary structures.
Long-term maintenance in rainy season: standardized management to delay pavement aging
In addition to emergency disposal, it is necessary to implement normalized long-term maintenance management in rainy season, standardize maintenance operation process, avoid maintenance errors and protect asphalt pavement performance in an all-round way.
Normalized cleaning and maintenance
Continue to do a good job of daily cleaning of the road surface, and timely clean up the gravel, sand and debris scattered on the road surface. Hard sundries will continue to wear and scratch asphalt pavement under rain soaking and vehicle rolling, destroy waterproof surface of pavement and accelerate disease generation. Keeping the road surface clean and tidy can effectively reduce road wear, water accumulation and other problems.
Strictly control the timing of maintenance operations
The permanent maintenance operation of asphalt pavement in rainy season shall avoid rainy and humid weather. When the pavement is not dry and the air humidity is high, the asphalt adhesive force will decrease greatly, and it is easy to fall off and crack after repair. Large-scale joint filling, surface covering and disease radical treatment shall be carried out in sunny and dry weather to ensure the quality of maintenance construction. At the same time, in accordance with the requirements of the specification, joint sealing and preventive maintenance operations should be carried out in advance to reserve sufficient time for the curing of construction effects.
Establish dynamic control of disease accounts
Detailed records shall be made for all kinds of pavement diseases, treatment methods and repair effects in rainy season, and dynamic maintenance accounts shall be established. Regularly re-open the sections with high incidence of diseases, optimize the maintenance scheme for pertinence, carry out special treatment for the repeatedly damaged sections, investigate the root causes from drainage, base layer, pavement structure and other dimensions, and realize accurate maintenance and long-term damage control.
Maintenance summary
The core inducement of asphalt pavement damage in rainy season is rainwater infiltration, ponding immersion and water flow erosion. All maintenance work should be carried out around the four cores of "waterproofing, drainage, damage control and repair". Adhere to the full-process maintenance mode of prevention before rain, control in rain, repair after rain and long-term maintenance, eliminate hidden dangers in advance, quickly dispose diseases and standardize operation flow, which can not only effectively reduce the probability of road surface water damage in rainy season, reduce large-area diseases, save maintenance cost in later period, but also continuously ensure the smoothness and integrity of asphalt pavement, safe and stable traffic, and prolong the service life of road to the maximum extent.
