The organization of parking space in the local area or in a garage cooperative requires a serious engineering approach, since the load from passenger or freight transport differs significantly from pedestrian. Base under paving stones It is the foundation of the whole structure, and it depends on its quality whether the coating will pass through one winter or will serve for decades. Errors at the stage of preparation of the "pie" of road clothes is almost impossible to correct without a complete dismantling of the coating, which entails significant financial losses.
Modern building codes and regulations (SNIP) clearly regulate the composition of layers, their thickness and materials used for areas with heavy vehicle load. Ignoring geometrical And the requirements for soil compaction can lead to the formation of tracks, washing out seams and destruction of curbs. In this article, we will discuss in detail how to properly form the load-bearing layer so that it can withstand the weight of the car even during the spring slurring.
The key point is the understanding that the paving is only the finishing coating, which distributes the point pressure of the wheels, but does not take on the main load. The entire weight of the machine is transferred through sand or mixture to the gravel-baseAnd then on the ground. If at least one of the lower layers is made with a violation of technology, the entire structure will become unusable. Therefore, compliance with the regulations is not bureaucracy, but a necessity for the longevity of your travel.
Regulatory framework and classification of loads
When designing a parking lot, it is necessary to rely on existing regulatory documents, such as: SP 34.13330.2021 (formerly SNIP 2.05.02-85*) "Roads" and GOST R 58653-2019which regulates the use of paving slabs and paving stones. These documents divide the operating zones into pedestrian and zones with the possibility of entering vehicles. For a passenger car, the load on the axle is much higher than when walking, which requires strengthening all layers of road clothing.
It is important to note that the standards require the calculation of the thickness of the structure depending on the type of soil of the base. Pulled clay soils require a more powerful cushion to compensate for frosty overflow, whereas sandy soils have better drainage properties. The minimum thickness of the base for paving stones for passenger cars should be at least 20-30 cm without taking into account the finishing surface. Neglect of this rule often leads to the fact that the cover "floats" in the spring.
There is a division into temporary and permanent coverage. For temporary parking, less rigid structures are allowed, but for a permanent storage place of the car, saving on materials is unacceptable. load-bearing capacity should be calculated with a margin that takes into account the possible appearance of heavier equipment (for example, trucks with the delivery of building materials or snowplows in winter).
Preparation of the earthbed and earthworks
The first step in creating a reliable base is the removal of the fertile soil layer. Plant soil (black soil, sod) is organic, which over time bends, decreasing in volume, which inevitably leads to drawdown. roadwear. The depth of the excavation is calculated as the sum of the thicknesses of all the layers of the "pie" plus the thickness of the paving stone itself. This is usually between 30 and 50 cm depending on the type of soil.
After the excavation of the soil, it is necessary to make a layout and sealing of the bottom of the trench (trench). For this purpose, a vibrating plate or skating rink is used. The density of the soil should be high to exclude its further shrinkage. If the soil is weak (peat, sludge), it may be necessary to replace or use it. geotextiles to separate layers and prevent mixing of rubble with the ground.
⚠️ Warning: Never leave a fertile layer under the ground! Organics will rot in 2-3 years, forming voids, because of which the paving stones will fall into uneven areas, creating pits.
Particular attention should be paid to the creation of a transverse slope for water runoff. Normatives recommend a slope of 1.5% to 2.5% (1.5-2.5 cm per 1 meter width). This will ensure the rapid removal of melt and rainwater, preventing moisture stagnation in the underlying layers, which is especially critical in winter when freezing and thawing.
☑️ Preparation of the earthbed
Crushed cushion formation
The gravel layer is the main bearing element of the structure, perceiving and distributing the load from transport to the ground. For parking cars, it is recommended to use crushed fraction 20-40 mm or 40-70 mm. The use of small crushed stone (5-20 mm) is possible only as a proppant of the upper layer, but not as a main filler, since it has a lower load-bearing capacity.
The thickness of the crushed stone layer for passenger cars should be from 15 to 20 cm. The material is covered with layers of 5-7 cm, each of which is carefully trampled. Quality sealing gravel-base provides the effect of "lock", when the stones are interlocked and form a monolithic plate, resistant to deformation.
In some cases, especially on weak soils, between the ground and gravel, as well as between crushed stone and sand, are laid geotextile. This material prevents silting of rubble (getting soil particles from below) and washing out of sand from above. This significantly extends the service life of the parking lot, while maintaining the drainage properties of the structure.
| Type of rubble | Faction (mm) | Strength | Recommended application |
|---|---|---|---|
| Granite | 20-40 | High (M1000-M1200) | main-stack |
| Gravel | 20-40 | Medium (M400-M800) | Country access roads |
| Secondary | 40-70 | Low/Mediocre | Temporary coverage |
| Limestone | 20-40 | Low (M200-M400) | Not recommended for cars |
Why is granite crushed stone better than gravel?
Granite crushed stone has a rougher surface and a cubic shape, which provides better adhesion (clutch) between the stones when trampling. Gravel, being rolled in water in nature, smoother and can "swim" under load, requiring more careful proppant.
Layer-leveling and mounting of curbs
After laying and tampering the rubble, a leveling layer is formed. For areas with cars, a mixture of sand and cement (CPC) or clean sand of a large fraction (2-5 mm) is most often used. The thickness of this layer is usually 3-5 cm. It is on this layer that the paving stones will be laid.
A critical element is the installation road-lock (Burd). The board not only marks the boundaries of the parking lot, but also serves as a retaining wall that keeps the paving stones from creeping under load. The curb is installed on a concrete cushion (cone) and must be fixed with a solution from the outside. The upper face of the curb is usually made level with paving stones or slightly higher (by 1-2 cm).
If the CP is used (a mixture of sand and cement in a ratio of 1: 3 or 1: 4), then after laying the tiles and pouring it with water, the mixture hardens, creating a rigid base. When using pure sand, the coating remains more flexible, but requires a perfectly working drainage system so that the sand does not wash out of the seams. Installation of curbs It must be done before the main area of the paving is laid.
Use a strained cord (beacon thread) to control the height of the alignment layer. This will allow you to lay the sand or the CHP exactly the first time without constant checks by the rule.
Coating technology and sealing
Laying of paving elements is made from the curb to the center or according to the selected pattern. The gap between the tiles should be 2-3 mm to compensate for thermal expansion and filling the seam. When laying, it is necessary to constantly monitor the level and compliance with slopes using a long rule or level.
After filling the entire area, the coating is vibrating. For this purpose, a vibroplate with a rubber lining is used so as not to damage the surface of the paving stones. Vibration is necessary in order for the tile to "set" on the leveling layer, and the inter-seam material to compact. The process is repeated 2-3 times with the sand in the seams.
⚠️ Note: It is forbidden to use a vibroplate without a rubber lining directly on the paving stones - this will lead to chips and cracks on the face surface of the stone.
The final stage is the sprinkling of seams with dry quartz sand. The sand fills the voids and fixes the stones. For the base CCF, the method of “spilling” with water is often used to start the reaction of hardening the cement in the seams, turning them into strong bonds. Finished coating It is not recommended to operate at full strength (car) for several days, especially if cement is used.
Common Errors and How to Resolve Them
One of the most common mistakes is saving on the thickness of the rubble. An attempt to save 5 cm of rubble by replacing it with sand leads to the fact that a track is formed under the wheels. Sand, unlike rubble, does not hold the shape under a high point load and is shifted to the sides. Recover such a coating can only be a full bulkhead.
The absence or improper installation of storm sewers and drainage trays leads to the erosion of the base. Water accumulating on the surface penetrates the seams, blurs the sand and washes small fractions from the rubble, forming voids. drainage system It must be designed so that water leaves the site faster than it enters.
The main reason for the destruction of the parking lot is not the quality of the tiles themselves, but errors in the preparation of the base and the absence of drainage. Water and weak soil are the main enemies of paving stones.
Questions and Answers (FAQ)
Can you just lay the paving stones on the sand without rubble for the car?
It's not recommended. The sand does not have sufficient load-bearing capacity to hold the weight of the car. Under the load of the wheel, the sand will shift to the sides, forming a track, and the tile will begin to walk and break. The gravel is required to create a rigid skeleton of the road.
What is the minimum thickness of the paving stones needed for a passenger car?
According to the regulations, 40 mm is enough for pedestrian zones, but for parking cars, the minimum thickness of the tiles should be 60 mm. For trucks or areas with heavy traffic, a thickness of 80 mm or more is recommended.
Do you need concrete for the car?
Pouring concrete foundation under the pavement (hard base) is one of the options, but not the only one. More often used "flexible" base (crushed stone + sand / DTP), which is cheaper, faster to install and better drains water. Concrete is needed only on very weak soils or under special customer requirements.
How often should you put sand in the seams?
In the first year of operation, it is recommended to add sand to the seams 1-2 times, since there is an active shrinkage of the base. In the future - as needed, usually every 2-3 years, if it is seen that the level of sand in the seams has fallen below the surface of the tile.