Smooth high-quality road surfaces, which provide full traction of the wheels of the vehicle with the canvas, are the key to safe and quiet traffic. Due to the active use of the road, they constantly need to be repaired and updated.
Currently, the most popular type of pavement repair is patching. This method is used more often than others, because it is much more profitable, more economical and faster. However, there are many complaints from drivers who complain about the quality of road surfaces and the rapid destruction of patches after repairs. But here the reason may lie not in the technology itself, but in those who use it. The quality of such repairs depends on compliance with the patching technology. Quite often, negligent workers do not even pay attention to the conditions and requirements that must be observed in the process of repairing roads, so an unfair and careless attitude to work often causes damage to road surfaces.
Benefits
The patching of the road does not imply any work to restore communications, landscaping: asphalt is laid only in areas that need urgent repairs. In addition, it should be noted that such work should be carried out in strict compliance with all points of the process. This guarantees cost savings, long life and maximum quality. Patching allows you to restore continuity, strength, evenness, adhesion and waterproof performance of coatings. In addition, it provides a standard service life sites.
Patching has been relevant for decades. There are dozens of technologies for carrying out such repairs of pavements, while the optimal method is selected based on weather conditions, the condition of the canvas, the possibilities of the full use of special equipment and the specifics of the materials used. Patching pavement has several indisputable advantages:
- there is no need to completely block the movement on the freeway / highway;
- operational implementation of all necessary work (small areas are restored within a day);
- lack of need to attract heavy special equipment;
- patching of asphalt pavement does not require huge financial costs (in comparison with the implementation of major repairs).
Recipe for success
Usually unscrupulous workers repair only the top layer of damaged areas. However, in fact, the technology of patching involves the restoration of the underlying layer.
Before starting work, the boundaries of damage are determined, existing defects are identified, potential defects are determined, the scale of work and indicators of reliability, uniformity, strength and roughness of the coatings are calculated.
Asphalt rolling
Many domestic enterprises that carry out repair and road construction have skating rinks weighing more than 8 tons. Such road equipment is justified in full-scale operations, but it is not practical to apply it for patching. For compaction of several tens of meters of the road, it is better to use the “stamping” method, which is implemented by the use of manual vibration plates. Asphalt patching is also performed using small paving or vibratory rollers.
Traditional method
With this repair method, the damaged area is first separated from the coating, this is done using a road mill. Then the edges of the potholes are cut to give them a rectangular shape. Then, the defective sector is cleaned of dust and crumbs of its edge and the bottom is treated with liquid bitumen emulsion or heated bitumen, after which the asphalt mixture is poured.
The patching of the pavement, the technology of which is traditional, allows you to get a high-quality result of work, however, it requires a significant number of operations. It is used in the repair process of various types of coatings from bitumen-mineral and asphalt concrete materials.
Repair with heating coatings and reuse of its material
Such patching of the road is based on the use of special equipment for heating coatings - an asphalt heater. This method allows to obtain high-quality results, save on materials, facilitate the technology of work. But at the same time, patching of asphalt concrete pavement has significant limitations on weather conditions (air temperature and wind). This method is used in the repair process of various types of coatings from bitumen-mineral and asphalt mixtures.
Repair without cutting down or warming up the old coating
Destruction and deformation of the road surfaces are filled with cold polymer-asphalt concrete mixture, wet organic-mineral mixture, cold asphalt concrete, etc. The method allows for work in cold weather with wet and wet surfaces, is simple to implement, but is not able to provide high quality and durability of the coatings. This method is used in the process of repairing pavements with low traffic intensity, temporary, and also as an emergency measure on roads with high intensity.
Cold patching methods
This is a patching of the pavement, the technology of which is based on the use of cold asphalt concrete or bitumen-mineral mixtures as a repair material. These methods are mainly used in the process of repairing from cold asphalt concrete and black gravel on low-grade roads and, if necessary, temporary or urgent sealing of potholes.
Work begins in the spring at an air temperature of at least +10 degrees. At the repair site, the coating is formed under the action of moving vehicles for 20-40 days, and its quality depends on the properties of the bitumen emulsion or liquid bitumen, mineral powder, composition and intensity of movement, weather.
Carrying out repairs is also possible at low temperatures, while repair materials are procured in advance. The cost of repairs using this technology is less than with the hot method. The main disadvantage is the short service life of coatings on roads with the movement of buses and heavy trucks.
Hot ways
They are based on the use of hot asphalt mixes as materials: cast asphalt concrete, coarse and fine-grained, sandy, etc.
The methods are used in the repair of roads with asphalt surfaces. It is possible to perform work at air temperatures of at least +10 degrees with a dry coating and thawed base. When using a heater, repair at a temperature of at least +5 degrees is permissible.
Hot processes provide higher quality and longer coating life.
Preparatory operations
Before work is carried out preparatory operations:
- Fences of places, road signs and lighting devices are installed during work in the dark.
- Marked places (maps) of repair with a chalk or a taut cord. The repair map is outlined in straight lines perpendicular and parallel to the axis of the road, giving the contour a regular shape and capturing an intact coating.
- Damaged coatings are cut, broken or milled, removed material is removed. It is carried out on the thickness of the destroyed coating layer, but not less than 4 centimeters along the entire length of the repair. When the pothole affects the bottom layer, it is loosened and removed to its full thickness.
- Potholes are cleared of material residues, dirt and dust.
- The walls and bottom are dried during the repair by hot method.
- The walls and bottom are treated with bitumen or bitumen emulsion.
Basic operations
Only after preparation can the potholes be filled with repair material. The installation technique and the sequence of procedures depend on the volume and method of work, such as repair material.
With small volumes and the absence of mechanized means, styling can be done manually. Mixing is carried out in a card in 1 layer when cutting down to a depth of 50 millimeters and in 2 layers at a depth of more than 50 millimeters. In this case, a coarse-grained mixture of crushed stone can be laid in the lower layer, and a fine-grained mixture in the upper layer.
For mechanized laying, the mixture is fed from a thermos hopper.
When closing cards 10-20 square meters. m asphalt mixes are laid by the paver. In this case, laying is done in a pothole, and the mixture is evenly leveled over the entire area.
The compaction of the asphalt mixture in the lower layer of the coating is carried out by pneumatic rammers, manual vibratory rollers or electric rammers in the direction from the edges to the middle.
The mixture and mixture laid in the top layer, laid in 1 layer at a depth of up to 50 millimeters, are compacted by self-propelled vibratory rollers or smooth-type static light rollers, and then heavy rollers.
For low-grained and sandy mixtures, the compaction coefficient should be not less than 0.98, for multi- and medium-grained mixtures - 0.99.
Hot mixtures condense at maximum temperatures at which deformation during rolling is impossible.
Joints that protrude above the surface of the coating are removed by grinding or milling machines.
Final operations
Final operations include measures to bring the road surface in readiness for the movement of vehicles. Workers clean up the remaining waste, garbage, load it into dump trucks. Also at this stage, road signs and fences are removed, the marking line is restored at the patching site.
Important requirements
The quality and service life of repaired coatings primarily depend on compliance with the requirements:
- patching is carried out at air temperatures not less than permissible for a certain repair material on a clean and dry coating;
- in the process of cutting down the old coating, weakened material is removed from all parts of the pothole where there are breaks, cracks and spalling;
- it is necessary to clean and dry the repair card;
- it is necessary to make the correct form of the card, steep walls, a flat bottom;
- necessarily treating all surfaces of the pothole with an adhesive composition;
- repair material is laid at the optimum temperature for this type of mixture;
- the layer should have a thickness slightly greater than the depth of the pothole, taking into account the margin of the compaction coefficient;
- the formation of a layer of new materials on old coatings at the edge of the map is inadmissible in order to avoid jolts during collision of vehicles and rapid destruction of sections;
- repair material is well leveled and compacted flush with the road surface.
Quality control
The polymerization of asphalt occurs at a temperature of more than 100 degrees and under high pressure. After compaction of the mixture, asphalt is not afraid of water. On the contrary, it is desirable to water the restored road surfaces for quick cooling and restoration of traffic.
It should be noted that in case of incomplete compliance of the technology and violation of some rules, asphalt concrete patches made can last at least 2 years. With strict observance of the repair technique - at least 5 years.
The carriageway must comply (after patching) with GOST R 50597-93 - "Roads and Streets".