In recent years, paving stones, colored and figured paving slabs and other architecturally expressive and practical small-piece paving elements have begun to return to the sidewalks and roadways of Russian cities. However, the culture of working with such materials does not always correspond to their functional and aesthetic capabilities.
Violations of the technology of laying small-piece paving elements, the use of materials that do not correspond to the purpose of the coating often leads to the fact that roads and sidewalks collapse, hump, individual elements loosen and collapse. Therefore, when laying small-piece paving elements, it is important to follow the technology, use the materials correctly and use special equipment to perform this type of work.
Work should begin with compaction of the roadbed to a stable state. In this case, special attention should be paid to the organization of its drainage. If the subsoil is wet with low bearing capacity, it is necessary to use geosynthetic materials. However, if the soil is sandy, it is often not necessary to lay the carrier layer at all.
Preparing the bed for a paved surface
The cross slope of the bed must match the cross slope of the outer covering. The thickness of the underlying layer is 2-5 cm. The upper limit must not be exceeded, otherwise the outer coating may deform under the action of the operating load.
Sand with fractions of 0-2 or 0-4 mm is most suitable as the material of the underlying layer. fine crushed stone with a size of 1-3 or 2-5 mm, as well as a mixture of crushed sand with crushed stone with a size of 0-5 mm. The size of large particles should not exceed 8 mm.
In areas with increased traffic loads, it is recommended to add cement or lime as a binder for the subbase.
In areas under roofs or sheds, the sub-base material is usually dry and loose. In this case, the paving stones are laid in a dry solution and the corresponding crushed stone mixture, and after laying all the gaps between the stones are filled with fine-grained sand.
All tiles or stones should be laid exactly in height, angle of inclination and taking into account the direction of the route (along the cord), leaving sufficient gaps for the joints.
With forced compaction (tamping), even the smallest placement errors cannot be eliminated. This also applies to gasket stones. However, gaskets cannot be considered a complete replacement for filling seams. They can only serve as an aid to ensure a certain joint width.
The location and dimensions of joints along the edges of curbs and other enclosing elements and structures must be planned in accordance with the modular grid. In this case, it is necessary to take into account dimensional deviations of ± 3 mm, due to the technology of manufacturing paving elements. This will allow the stones or tiles in the covering to be replaced if necessary.
To ensure the straightness of the seams, the cords are pulled approximately every 3 m in the longitudinal direction. When marking large areas, it is necessary to pull the cords in two directions and check the observance of right angles every 1-3 m.
As a framing of paved areas, curbs or edging stones placed in a concrete bed should be used, which, as a rule, reliably take the load on the edges of the pavement. These barriers are installed prior to laying the outside of the pavement to prevent cross mixing and settling of stones.
The plots adjoining buildings are laid so that surface water flows not to the building, but from it. Otherwise, it is necessary to provide gutters and drainage grates at the building itself.
In accordance with the requirements of the DIN 18318 standard, the unevenness of the outer surface within a 4-meter control section of a pavement made of concrete stones and concrete slabs should not exceed 10 mm. However, this criterion should always be considered in conjunction with the structure of the outer pavement. The difference in the height of concrete stones is usually compensated for by laying them in a relatively loose sandy bed.
Advantages of paving slabs
Paving slabs are a very technological material, they can be laid manually or with the help of tile-laying machines, and the presence of seam formers allows this to be done as quickly as possible without preliminary adjustment with a guaranteed gap.
There are no puddles on the surface of paving slabs. The presence of gaps allows moisture to freely penetrate and evaporate through the tile coatings and prevents the formation of water mirrors under the coating.
Recent studies have shown that asphalt pavement, when heated above 25 degrees Celsius, begins to release carcinogenic substances into the atmosphere. This means that it is dangerous to be in the city on sunny summer days!
Under natural climatic heating, paving slabs do not soften and retain their strength properties, do not emit, unlike asphalt, volatile harmful substances.
Unlike asphalt, it does not violate the natural need of green spaces for gas and water exchange, which has a beneficial effect on the appearance of the city and the health of citizens.
The service life of the paving stone is at least 25 years (since the frost resistance of the paving stone is 200-300 cycles). The porous structure allows water to escape through the tile into the substrate, so the tile surface does not deteriorate.
If it is necessary to carry out repair work (for example, the laying of underground communications, etc.), the paving slabs can be easily disassembled, the necessary work can be carried out and laid again. "Paving stone" is recommended to be used in urban conditions in places where underground communications are located.
The color scheme of the tiles can be varied, and the color saturation is not lost over time.