China's construction of asphalt pavement history is short, mature maintenance and repair technology is less, coupled with the rapid development of China's national economy in recent years, resulting in rapid growth in traffic volume, large vehicles, serious overloading, vehicle channelization and other issues, so that many asphalt pavement has appeared early damage phenomenon. Cracks are the early manifestations of various diseases on the highway, so it is particularly important to treat cracks.
In the process of dealing with crack diseases on highways, through the promotion and use of new materials and new technologies, the construction quality is improved, the construction cost is reduced, and energy savings and ecological environment protection can be maximized.
<h1 class="pgc-h-arrow-right" data-track="6" >. Analysis of the types and causes of cracks in highway asphalt pavement</h1>
The manifestations are: a horizontal crack that is close to the perpendicular to the midline of the road; b A crack in the longitudinal seam that is roughly parallel to the midline of the road.
Causes: a deformation between the longitudinal plates of the compacted concrete slab or cast-in-place concrete slab or between the horizontal plates is uncoordinated, under the repeated action of vertical load stress and temperature warp stress, different vertical deformations appear between adjacent plates, causing the asphalt concrete at the seam to stagger, resulting in reflective cracks; b Due to temperature stress and horizontal load, the cement concrete plate produces horizontal deformation, and the deformation of cement concrete and asphalt concrete is uncoordinated and causes reflective cracks.
Manifestations: transverse, longitudinal, oblique and cracked.
Causes: Under the joint action of load fatigue stress and temperature fatigue stress, the main bearing layer - the corner corner of the cement concrete slab or the intersection of the construction joint and the oblique crack is broken due to the concentration of stress, and the asphalt surface layer on it is cracked with the fracture and serious deformation of the plate.
<h1 class="pgc-h-arrow-right" data-track="45" > second, the treatment scheme of highway asphalt pavement cracks</h1>
In the process of repairing cracks, in addition to the traditional hot-mix asphalt concrete method for repair, combined with the new materials and new processes developed in recent years, under the guidance of relevant experts, a variety of practical and economically applicable materials and methods for repairing asphalt pavement cracks have been tried.
Polymer grouting is used for pavement reflection cracks, and the grouting process is: positioning → drilling→ grouting preparation→ grouting → sealing holes and on-site cleaning→ controlling traffic (health maintenance 15min) → quality inspection.
Advantages: In practical applications to avoid large areas of damaged pavement, grouting 15min can resume traffic, normal use, with fast grouting process, small traffic interference, small grouting holes and other advantages, is a new technology for rapid maintenance.
Precautions: timely cleaning of wastewater, waste slurry and residue during the drilling process, timely cleaning of dirt after grouting, keeping the road surface clean; reasonable allocation of Baotong personnel to ensure safe construction; timely removal of construction waste, keeping driving smooth; inspection of machinery, preparation of grouting materials for proper storage.
Construction conditions: a construction is relatively convenient, can be carried out at room temperature; b after the completion of construction, there is no obvious color difference with the asphalt pavement, the performance effect is good; c after the completion of construction, it can open traffic in the shortest possible time to reduce the impact on traffic; d The material and construction requirements are not high.
Construction procedure: artificial seam clearance→ high-pressure air blowing seam→ glue injection → seam smearing.
Advantages: a can seal water, impermeable after sealing; b is well combined with asphalt concrete, and has a certain bonding strength; c has a certain strength and good ductility, deformation ability and tear resistance is strong (the maximum tensile elongation can reach 400%), can adapt to the change of crack width caused by temperature difference; d weather resistance and high temperature, low temperature stability are good; e wear resistance, aging resistance, with good durability; f corrosion resistance, non-toxic, non-polluting; g has repairability, new and old compatible.
Operating procedures: preparation → preparation materials→ slotting (along the crack direction) → clearing the seam (blowing with a blowgun or forest fire extinguisher) → irrigation seam (pressure irrigation machine) → observation → secondary irrigation → manual scraping to form a sealing film→ curing→ quality inspection → open traffic.
Precautions: a the depth of the groove should be greater than the width; b should ensure that the road surface is dry during construction; c the groove should be cleaned after the groove; d After filling the sealant into the groove, apply a scraper to scrape the seam flat
<h1 class="pgc-h-arrow-right" data-track="46" >3</h1>
Patching cracks in highway asphalt pavements is a recurring task. How to improve the crack repair process, improve the quality of repair, and extend the service life of the road surface is an important problem that needs to be solved urgently. In order to ensure the quality and life of the filling seam, three conditions must be met: a filling seam material should have good adhesion; b the filling seam material should have excellent elongation and elasticity at low temperatures; c the filling seam material should have long-lasting anti-aging and anti-fatigue ability.
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