Maintaining the normal technical condition of roads involves regular maintenance and timely elimination of defects that inevitably arise during their operation.
One of the most widespread ways to restore the roadbed is patching, which is used when the damaged area is small. Such repair is notable for its cost-effectiveness and high speed.
Such a method of restoration of road surfaces is actual in the presence of potholes, cracks, swellings and other damages, the area of which allows to do with local patching and does not require major repairs.
What is the importance of regular patching?
The smooth and undamaged surface of the highway is one of the indispensable conditions for its safe and comfortable operation by all road users. The freshly laid surface corresponds to these requirements in full measure, but it is exposed to numerous loads and adverse factors on a daily basis: weight of a moving transport, precipitation, and treatment with chemicals in the winter period. As a result, even the highest quality coating over time is subjected to wear and tear and destruction.
It should be noted that the characteristics of pavements themselves are initially far from ideal, since organizations involved in the process of their construction, often make mistakes in the design and paving, using substandard materials in order to save money, which significantly reduces the time interval between ongoing repair measures.
It is important to eliminate the deformities at the initial stage because untimely repair activities can lead to a number of negative consequences:
- Improving the scale of the problem. Any crack or pothole under the influence of incessant loads is subjected to further destruction, which subsequently leads to the need to use more time-consuming and costly technologies for the restoration of asphalt concrete pavement.
- Deformation of the underlying pavement layers. A small surface hole or a crack breaks the impermeability of the road surface and as a result, the moisture from atmospheric precipitations and snow melting gets into its depth. Such a situation is especially detrimental during the interseasonal period, since regularly changing cycles of thawing and frost lead to a constant change of water volume, which destroys the road right from the inside.
- Reduced comfort and safety in using the road. Any bumps in the road surface, under certain conditions, can cause a road accident.
Technology for patching
The choice of optimal technology for road rehabilitation is often determined by the time of year since the climate in many regions of Russia is characterized by variability.
Optimal conditions for the work are dry weather and a fairly stable temperature of at least +5°C / 41°F. It is better not to neglect such recommendations, as it may lead to a decrease in the quality of work and rapid destruction of the repair patching.
The specifics of the patching methodology are to fill the areas of deformation with a special repair mixture on a bituminous basis. This rehabilitation option is acceptable if the total cumulative size of the damaged areas does not exceed 15% of the total area of the road.
Before the patching itself, a number of preparatory processes are obligatory:
- Punching of markings to cut the map.
- Dismantling of the damaged area. Cutting out the map is carried out by cold milling, with the use of floor saws, and with the help of a jackhammer. The last option is less common since it does not provide sufficient quality edge processing.
- Cleaning the map from debris and dirt and ensuring that it dries, if necessary, using a thermal lance or other equipment capable of providing a high-temperature effect.
Types of patching by material and technology used
The primary methods of patching include:
- Asphalting with hot mixes;
- Asphalting with cold mixtures;
- Patching with casting mixtures;
- Stroy-injection technology;
- Infrared repair of asphalt.
Asphalting with hot mixtures for patching
Hot asphalt patching is one of the most widespread ways of patching the road surface. In spite of the necessity to use special equipment for hot asphalt mixes delivery to the place of work and its subsequent maintenance at temperature, such method of asphalting is very widespread in repairing.
This is due to the highest level of adhesion of hot mixtures to the substrate, but in order to provide it, the restored areas need to be properly compacted, which complicates the technological process and increases the amount of time required for the work. In addition, the disadvantage of hot asphalting is a strong dependence on weather conditions.
The laying of such compositions is categorically prohibited at subzero temperatures.
Asphalting with cold mixes for patching repairs
From the point of view of weather restrictions, cold asphalting is more universal, since it may be performed even at low negative temperatures and in conditions of pronounced wetness, but in order to ensure the high quality of works it is still advisable to conduct them during the warm season.
In this case, it is necessary to take into account that the patching made by a method of cold asphalting has a lower durability, as a result of which such technology of road patching is used for the restoration of pavements on the roads.
Patching with casting mixtures
This repair variant is especially actual for urgent or emergency repair of road surfaces since it allows to perform the restoration of the damaged sections as quickly as possible. Liquid compounds with a temperature range of +180-250°C (356-482°F) are used to fill potholes and are poured into potholes. One of the main advantages of this technology is the ability to quickly repair large enough sections of road, the compound’s excellent adhesion to old materials and the lack of the need for compaction.
Jetting-injection technology
This method of repair is appropriate when small potholes, potholes and cracks must be repaired. The jet-injection technology is appreciated for its simplicity and high speed of processing, as well as its economical use of materials. When using this method of repair, a thin layer of water-bitumen emulsion is sprayed on a pre-prepared area to be restored, after which black crushed stone with a fine fraction is placed in the cavity and sprayed with the emulsion composition.
It should be noted that road patches made by this method are inferior to patching made by other technologies in terms of durability, so the jet-injection technology is used for the repair of road surfaces with low load and low traffic intensity.
Patching with infrared heating units
The usage of infrared systems allows for providing the highest quality of repair comparable with the result after the complete overhaul (provided that the condition of the road base is normal).
The main advantages of infrared heat treatments are:
- The absence of temperature differences when laying materials, allows cold joints to be avoided, which contributes to stronger joints between the patching and the old road surface.
- Economical use of resources.
- High speed of repair work.
Thermal profiling implies the use of special units for repairs.
