Paving is one of the oldest construction methods for paving squares and streets. Even today, they are still omnipresent, e.g. in the streets of historic old towns. However, paving surfaces are also popular in public areas that need to be redesigned, in private gardens and driveways, on terraces and garden paths, as they can withstand high loads and offer a variety of design options with the choice of material, format and installation pattern.
18318 VOB C only covers paving surfaces and slabs that are laid using the unbound construction method. This is considered a standard construction method for paved areas. However, the unbound paving method is often not suitable for today's requirements resulting from road traffic (heavy goods traffic). Ruts, displacement of the paving stones, subsidence, etc. are the result. Unbound joints are also regularly damaged by sweepers and vacuum cleaners.
Public areas are therefore primarily designed in bound construction according to RStO (Guidelines for the Standardization of the Superstructure of Traffic Areas). The RStO describe standard construction methods for the reinforcement of traffic areas in public road space, which can also be used for the planning of the superstructure of private paved areas.
ofmaterials: When choosing the material for a paving surface, the material properties and functionality of the paving material, which must meet the usage and load requirements of the respective traffic area, are decisive for the planner in addition to design aspects (appearance of the material, paving format, laying pattern, etc.). These include, in particular, weather resistance, de-icing salt and abrasion resistance, fracture resistance, slip and slip resistance, but also the cleaning and maintenance effort involved. Natural stone paving is generally much more expensive than concrete block paving.
Formats: For the individual paving formats (classic formats, composite pavements, brick slips, slabs, quarry stones and pebbles), see lexicon article ►Paving coverings, formats.
Laying patterns: There are numerous laying patterns, which are often also subject to regional influences. For example, arch paving is mainly found in southern Germany, while passepflaster is widespread in northern Germany. However, the common laying patterns have mostly been created not only from a decorative point of view, but also from a practical point of view. An attempt is made to optimise the stability of the paving stones in relation to each other by means of the joint pattern and thus prevent later slipping or displacement. When planning drivable surfaces, it is important to avoid joints running parallel to the direction of travel, as these promote sagging of the paving stones and can thus lead to ruts. Installation patterns with joint courses at a 45° angle to the direction of travel are most favourable for roadways.
In order to avoid constraints or displacements in unbound construction, material- and format-dependent joint spacing in accordance with DIN 18318 must be observed. Wooden paving in particular swells strongly when damp, but paving slabs made of natural or concrete stone can also experience temperature-related changes in length due to intense sunlight that should not be underestimated.
For areas in design-demanding areas, it is advisable to create a laying plan. Frequently used laying patterns: see lexicon article ►Laying patterns for paving surfaces.
Breaking load, drivability: Paving surfaces made of concrete block, clinker brick and especially natural stone can also be suitable for high pressure loads, such as those that occur in heavily trafficked areas. The manufacturer's information on the respective product must be observed. The paving format and paving stone thickness are to be chosen depending on the expected traffic load. For example, highly frequented streets are usually designed as cobblestones, while footpaths or areas with little traffic are designed as small stone pavements. Mosaic stone pavements are usually found on impassable surfaces.
In the case of permeable concrete paving stones, it should be noted that concrete with porous debris generally has a lower load-bearing capacity than structurally dense concrete.
In the case of very high loads and heavy traffic, such as those that can occur on public roads, engineering planning according to RStO makes sense in order to meet the requirements for the load-bearing capacity of the pavement according to the RStO load classes.
Construction methods: When it comes to paved surfaces, a basic distinction is made between unbound and bound construction. The unbound construction method with binder-free materials is the norm for paving surfaces. In bonded construction, building materials containing binders are used for bedding, base course and usually also for the joint material.
Regardless of the type of construction, care must be taken to avoid the accumulation of moisture above and below the paving surface. The choice of the installation system should always be made taking into account the individual installation situation, taking into account in particular requirements for load-bearing capacity (e.g. due to road traffic), but also ease of repair and cleaning or expected costs. In the case of paving on roof terraces, the flat roof guideline must also be included in the planning.
Unbound construction: As a standard construction method for paved surfaces, the unbound construction method has been introduced in DIN 18318 VOB C. This is the laying of the paving stones in a bedding layer about 3 to 5 cm thick (crushed sand-chippings mixture), underneath which is a coarse-grained base course of a crushed sand-gravel mixture. If the risk of frost is high, an additional frost protection layer underneath the base course is necessary.
The sequence of layers and layer thicknesses of the superstructure (pavement, bedding, base and frost protection layer) are always based on the expected stress.
If it is not sufficiently permeable, the subgrade below is provided with a gradient of at least 2.5 % in order to safely drain water or direct it to a drainage system. All layers must be filter-stable in relation to each other in order to avoid material leaching.
In the case of unbound construction, an edge edging of the surfaces is mandatory.
Image: Layer structure in unbound construction - bauwion
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for concrete paving stones: Concrete paving stones are mainly made with spacers that sit on the side surface of the paving stone as a "concrete nose" and are no longer visible when the joints are filled. They are used to comply with the minimum joint width of 3 mm according to DIN 18318 VOB. However, direct contact of the concrete spacer with the neighboring paving stone should be avoided. The most favourable joint width for concrete paving stones is generally 3-5 mm, except for large stone thicknesses and special installations, such as eco-paving. This gives the paved surface the necessary elasticity and makes it easier to fill the joints.
Joint filling and shaking: The joint material has the task of elastically supporting the paving stones among themselves. It is therefore essential to completely fill the joints and shake the surfaces with the surface vibrator to compact the joint material and strengthen the position of the stones. With the filling material, it is important to make sure that it does not contain any colouring components such as clay and is completely dry. After sweeping in the joint material, the paving surface must be carefully swept and cleaned before the shaking process. A rubber mat under the vibratory plate prevents permanent scratches of the stone surfaces. After the shaking process, the joints are filled again. Filling and shaking processes may have to be repeated until the joint is completely filled.
Efflorescence: In so-called efflorescence, hydrated lime dissolved in water reacts with carbon dioxide from the air to form calcium carbonate and is visibly deposited on the surface of the paving stones. In a construction method with open joints, efflorescence caused by leaching from the joint and bedding material cannot be avoided, but does not constitute a defect. As a rule, they are rubbed off with stress on the pavement or come off due to weathering.
Cleaning and care: Sweeping with a broom and cleaning with water are usually sufficient to clean normal soiling. For heavier soiling, only specialized cleaning agents should be used for the respective paving material in order to avoid damage to the pavement. In principle, the water hardness must also be taken into account for the correct dosage of the recommended cleaning agent.
Soft soaps are generally considered harmless for concrete blocks .
For natural stone paving , manufacturer's recommendations should be followed when choosing a cleaning agent. For example, no acidic cleaning agents should be used on non-acid-resistant types of rock (e.g. limestone, marble). Alkaline cleaners should have a pH < 10.5 to avoid matting of surfaces. While alcohol cleaners may be used on hard rock, they can cause the surface to fade and gray on soft rock.
Wooden paving is not normally treated with chemical cleaners. In addition to washing up with water and natural soap, care with wood oils is possible.
The use of high-pressure cleaners is also critical, especially for water-permeable concrete paving stones (risk of reducing drainage due to surface injuries) and for soft natural stone paving surfaces, e.g. sandstone, whose surfaces are increasingly susceptible to dirt due to fine spalling. In addition, the jet of a high-pressure cleaner causes the joint material to wash out in the case of unbound joints, which can lead to instability of the covering.
The corresponding permissibility/harmlessness of cleaning agents that can get into the groundwater must be ensured in any case.
Impregnation: Natural stone, concrete block or clinker paving is often supplied with a factory impregnation. However, this can also be applied after installation or re-impregnated in use.
While layer-forming sealants are not advisable outdoors (risk of frost damage if moisture penetrates), the cleaning of a paved surface can be made easier by impregnation. Nano-effects protect in particular against stains (e.g. oils, red wine), but do not provide protection against acids, e.g. from fruit juices and lemonades. Overall, the adhesion of dirt particles to the paving material is made more difficult by impregnation.
The respective impregnating agent should always be coordinated with the manufacturer before use or suitable for the respective plaster material. The use of unsuitable impregnating agents can cause undesirable visual effects on the surfaces. A trial treatment makes sense.
To avoid damage, impregnations may only be applied to cleaned and dry surfaces.
DIN EN 1338, Concrete paving stones - Requirements and test methods
DIN EN 1338 Corrigendum 1, Concrete paving stones - Requirements and test methods; Corrigenda to DIN EN 1338:2003-08
DIN EN 1340, Concrete kerbstones - Requirements and test methods
DIN EN 1342, Natural stone paving stones for outdoor use - Requirements and test methods
DIN EN 1342/A20, Natural stone paving stones for outdoor use - Requirements and test methods; Amendment A20
DIN EN 1343, Natural stone kerbstones for outdoor use - Requirements and test methods
DIN EN 1343/A20, Natural stone kerbstones for outdoor use - Requirements and test methods; Amendment A20
DIN EN 1344, Paving bricks - Requirements and test methods
DIN EN 12440 Natural stone - Criteria for the designation
DIN EN 12670 Natural stone - Terminology
DIN 18318 VOB C Procurement and Contract Regulations for Construction Services - Part C: General Technical Contract Conditions for Construction Services (ATV) - Traffic Infrastructure Construction Works - Paving surfaces and slab coverings in unbound design, edging
DIN 18503, paving bricks - requirements and test methods
DIN 18507, paving stones made of porous concrete - terms, requirements, tests, monitoring
RStO - Guidelines for the standardization of the superstructure of traffic areas, Forschungsgesellschaft für Straßen- und Verkehrswesen
TL Paving - StB, Technical Terms and Conditions of Delivery for Construction Products for the Manufacture of Pavements, Slab Pavements and Edging in Road Construction
ZTV Pflaster - StB, Additional Technical Terms and Conditions and Guidelines for the Production of Pavements, Slab Pavements and EdgingEnd of Form
M FP - Leaflet for Surface Reinforcements with Pavement Surfaces and Slab Coverings in Unbound Design as well as for Edging, FGSV-Nr. 618/1, Publisher: Verlag der Forschungsgesellschaft für Straßen- und Verkehrswesen
Working Paper - Surface Reinforcements with Pavement Surfaces and Slab Coverings in Bound Design,FGSV-Nr
. 618/2, Publisher: Verlag der Forschungsgesellschaft für Straßen- und Verkehrswesen
M VV - Merkblatt für Verseeterungsfähige Verkehrsflächen, FGSV-Nr. 947, Publisher: Verlag der Forschungsgesellschaft für Straßen- und Verkehrswesen
FLL - Guideline for the Planning, Execution and Maintenance of Greenable Surface Reinforcements, Publisher Forschungsgesellschaft Landesentwicklung Landschaftsbau e.V.
Natural Stone Expert Talks, Series of the Journal Naturstein, Publisher: Ebner Verlag GmbH & Co KG
► Arbeitsgemeinschaft Pflasterklinker e.V.
Source: bauwion
