Hundreds of thousands of kilometers of roads are laid and repaired annually. New construction, as a rule, is carried out taking into account modern loads and with the use of new technologies, but the repair of an existing canvas, the so-called patching, is often carried out in outdated unproductive ways.
The end result is of poor quality. Road geogrid is a modern cellular structure material used in the repair of roads. Technologies involving the use of this material are notable for the high quality of work performed.
The use of road geogrids
The construction of new and repair of existing roads for various purposes is the main industry where the road geogrid is used. Depending on the technology, laying can be carried out in all layers of the road surface. The main purposes of the road geogrid:
- Reinforcing plots during repair. The geogrid is laid on a damaged area of asphalt, and a new coating is placed on top of it. The structural properties of the mesh prevent the new coating from contacting the old cracks. In this case, the layer takes on most of the horizontal stresses.
- Dents and ruts may form at the places of greatest stress on the roadway. When repairing, the geogrid is laid in recesses on top of asphalt concrete. This allows you to distribute the load evenly over the entire area, preventing the formation of new dents.
- Laying the geogrid in the pavement is carried out by pairing various types of coatings (for example, asphalt and cement-concrete) to prevent cracking.
- Reinforcement of joints between concrete slabs. When applying asphalt pavement to the base of concrete slabs, weak points are formed at the joints, on which a road geogrid is laid to reinforce the canvas.
- When the road widens at the junction of the existing and new pavement, cracking is possible. To prevent this, the joint is reinforced with a geogrid.
- Modern technology often involves the preliminary reinforcement of soils. For this, a road geogrid is also used. The use of a reinforcing layer in the construction of a roadway is an integral part of the process.
Varieties of geogrids and their properties
The type of geogrid determines its application. In addition to the material and cell size, the material is distinguished by the method of formation: biaxial (double orientation) and uniaxial (mono-oriented). Biaxial products with rectangular cells are designed for the construction of roads, including on soft soils. Double orientation geogrids distribute loads well, which contributes to an increase in service life. Uniaxial layers of elongated cells have high tensile strength, are excellent for strengthening soils, landslide areas and sprinkling foundations.
Products for the reinforcement of asphalt concrete
The road geogrid for the reinforcement of asphalt concrete allows you to distribute local external loads throughout the entire volume of the nearby canvas. This material is used to extend the life of concrete-backed lines, which are becoming more and more every year. This grid also distributes internal stresses arising from the shrinkage of gradually hardening concrete.
Reinforcement of concrete with a metal mesh is short-lived and expensive. Fiberglass and polymer geogrids are a cheaper alternative to metal reinforcement and at the same time have all the necessary characteristics:
- The material of such products is chemically inert, not affected by temperature extremes and the alkaline environment of concrete.
- It has a unique ability to distribute local loads.
- It has a low weight, long service life, easy installation and affordable cost.
To improve performance, the foundation used in road construction is treated with bitumen.
Geogrid for road construction
The road surface is subjected to daily loads from traffic flows, which inevitably leads to its destruction and the formation of pits, potholes and cracks. The main reason for this is inadequate ground preparation. The geogrid of the pavement improves the strength characteristics of the asphalt concrete pavement, tensile strength and optimizes the perception of horizontal stresses.
The use of such materials both in the construction of new roads and in the repair of existing ones can significantly increase operational characteristics and increase the service life of the coating. The use of a geogrid for road construction in combination with geotextiles allows to reduce the necessary volume of non-metallic bulk materials during road construction, which will significantly reduce the cost of the project without changing the quality of the structure.
Polymer Geogrids
The road geogrid made of polyester fibers with a polymer coating is made using thread knitting and piercing technology. This allows you to maintain the original high strength of the material. The geogrid structure is fixed cells with a size that is larger than the material being filled. Due to this, the backfill interacts with the base (soil, rock, another base of materials used in construction).
Polymeric materials are used as a reinforcing layer in the lower layers of the base of the road. The use of polymer nets in road structures allows reinforcing the road base and preventing the interpenetration of materials of different contact layers. Reinforcement is achieved by restricting the movement of granules of bulk material of the base outside the cell. The formed composite layer (geogrid + granular material) has a high resistance to dynamic loads.
Fiberglass products
Fiberglass-based geogrids are used as reinforcing elements and protective separation layers in the construction and repair of federal and regional highways, airfields, bridges and overpasses. The use of fiberglass nets for reinforcing asphalt concrete coatings allows to increase the operating time between repairs by 2-3 times. The cost of maintaining roads in regions where fiberglass geogrids are actively used is reduced by 40%. Such materials have high technical and physical properties: resistance to aggressive environments, the ability to withstand high lateral and longitudinal loads. Fiberglass geogrids significantly improve the strength and mechanical characteristics of reinforced elements.
Production
To date, the following main types of geogrids are produced:
- extruded polymer;
- glued fiberglass;
- piercing nets made of polyester yarns and fiberglass.
Modern technologies and equipment with a wide variety of production methods make it possible to produce geogrids with various properties, from different raw materials and with different fasteners in nodes. The main requirements are:
- resistance to natural factors;
- resistance to aggressive environments in operating conditions;
- resistance to ultraviolet;
- resistance to pollution;
- strength and stability properties.
Material selection
From the variety of types of geogrids and their sizes, the choice should be based on the purpose, the method of forming the cells and the type of raw material. Interlayers are intended for reinforcement, separation of layers, erosion control, soil and base leveling. Having decided on the purpose, you need to choose a specific type of geogrid and its size. Depending on the properties of the raw material, the characteristics of the material are selected, which can be resistant to hydro-, bio-, thermo- and chemical effects.