Pavements made according to standard construction standards must meet a wide range of requirements. The coating must be strong, durable and have optimal insulation of the upper layers. However, not in all areas it makes sense to equip multilayer canvases. More affordable and optimal in terms of characteristics is the filling of roads with a special filler. A correctly selected fraction will allow the formed base to be used for a long time without the need for regular repairs.
Backfill material
The basis for the dump material is usually the loose remains of old road surfaces - for example, particles of concrete, asph alt and even soil. The use of sand with gravel is also practiced, but such options are more expensive. Based on the combination of operational qualities, it is more expedient to use asph alt crumb. Such backfilling of roads with the addition of a binder bitumen after compaction provides a moisture-resistant and durable foundation. The reliability of the coating is due to the high density, but on condition that a high-quality plasticizer was used, and compaction was carried out with special equipment.
The advantages of asph alt filler include resistance toclimatic influences. Frost and precipitation are not terrible on such a basis. This, by the way, is the main difference from traditional road components. So, filling the road with rubble in practice can be washed away by rain. This also applies to sandy substrates, which, without a proper bituminous bond, only last for short periods. However, there are also disadvantages of asph alt dumps. Under the influence of sunlight, the plasticizer may melt and, as a result, soften the web.
Road Filling Technology
It should be noted right away that the use of several materials in one backfill is not allowed, except for special cases provided for by the project. Direct work is done from the edges of the base to the middle in layers. In this case, the entire width of the operated part should be covered, including sloped parts with soil. Secondary and additional dumping is not allowed due to its inefficiency. All subsequent inclusions will be washed off during use. However, in some cases, road filling provides for the possibility of expansion. After completion of the working steps, excess soil and filler are removed from the canvas. It is not necessary to take it out - if necessary, you can arrange additional filling along roadsides and exits.
Dump compaction
This part has a greater influence on the formation of the qualitative characteristics of the coating than the initial application of asph alt chips or crushed stone. Before compaction, each layer is leveled in accordance with the value of the longitudinal slope. Next, you can start rolling the canvasusing special equipment across the entire width of the road. In some tight spaces, spot compaction should be performed. In order for the roadbed to be solid along the entire horizontal, problem areas are rammed manually using vibro-impact actions. At the same time, tamping plates cannot be used in areas where engineering communications are laid.
When using loose fillers for the roadway, it is recommended to compact with lattice or cam rollers. This technique is used at the first stage, it is also possible to use machines on pneumatic tires, which have an incomplete load of ballast - by 10-15 tons. At the final stage of compaction, road filling is compacted with pneumatic tires, the mass of which reaches 25 tons.
Restoration of roads by backfilling
If the device of full-fledged canvases by backfilling is more often performed with asph alt chips, then in the case of repair of typical road structures, it is still recommended to use crushed stone. During capital restoration measures, a complete change of layers is carried out. Backfilling occupies only a separate part in such works when creating a preparatory layer. The road surface is sprinkled with crushed stone in several layers. The first is a layer of a large fraction, after which it is replaced by a fine-grained coating. This is exactly the case when backfilling can be combined with asph alt concrete, acting as an auxiliary technological layer. If the area of the deformed section on the road does not exceed 25 m2, then instead of backfilling it is recommended to carry outstandard patching.
When is backfill used?
In the traditional version, backfilling is performed in areas that do not experience even average traffic loads. In particular, the creation of such canvases on access surfaces outside the city is practiced. Also, with the help of this technology, a wide range of reconstruction works is carried out. By itself, backfilling is a necessary layer in typical constructions, therefore, in areas where there are no increased requirements for the upper layer, the road surface is left in the form of compacted asph alt chips. As for the use of material as a technological component, crushed stone, for example, can act as an effective drainage layer.
Conclusion
As technology advances, so does the quality of road surfaces. The use of modern technology, binder additives in solutions and effective laying principles allows the formation of durable road structures. But, high quality is achieved at the expense of an appropriate price, while in some cases laying a full-fledged coating does not justify itself. It is in such situations that it is advisable to use a roadbed formed by backfilling. The main advantage of this technology is its availability and low price. This is a recycled material, which, in essence, is recycled asph alt from old pavements - accordingly, it can be obtained with little or no investment. It remains only to fill and compact the mass of the canvas in accordance with the requirements for a particular site.
