Permeable Gravel Stabilised paving

Transcription

1 Permeable Gravel Stabilised paving 1

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3 Index. A. The principle of Nidagravel gravel stabilisation... 5 B. Pavings: for what applications?... 5 C. Different types of paving... 6 C.1. Clinker and asphalt pavings. C.2. Gravel pavings. A) Benefits and problems B) Choice of gravel or shingle C.3 Nidagravel gravel stabilisation. D. Product description... 8 E. Specification text... 9 F. Installation F1. The substrate: practical advice. F2. Edge retainers F3. The Nidagravel gravel stabilisation sheets. A) General B) Installation on inclines F4. Filling the Nidagravel sheets with decorative gravel. G. Maintenance of Nidagravel gravel stabilisation G1. Nidagravel maintenance G2. Weeds G3. Salt /snow G4. Wear / ageing H. Contact details

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5 A. The principle of Nidagravel gravel stabilisation. Extruded polypropylene sheets with a honeycomb structure form the base material. The size of the honeycomb is selected according to the chosen gravel calibre. The substrate must be prepared according to the anticipated loads (see below). The Nidagravel gravel stabilisation sheets, which have already been provided with a geotextile on the underside, are placed on this. These sheets are filled with an excess of gravel so that the sheets are invisible. Benefits: - You retain a perfectly porous paving - Your paving offers you high functionality (for walking and driving comfort). - The gravel retains its colour - The paving requires very little maintenance B. Pavings: for what applications? The intended target groups of pavings for Nidagravel gravel stabilisation are: Driveways Public parking places Private car parks Cycle paths Cemeteries Terraces, gardens, patios Playgrounds Garden paths Roof-garden paving 5

6 C. Different types of paving. The advantages and disadvantages should always be weighed up when choosing a particular paving material. It goes without saying that one type of paving will not be the most suitable in all cases. The following table provides an overview of commonly used paving materials with a number of criteria that will influence the choice of paving. The table indicates how pavings behave with regard to these criteria. Gravel / shingle Clinkers / Asphalt Nidagravel gravel stabilisation Porosity Passability on foot Passability for cars and lorries Maintenance Formation of pits and ruts Colourfastness Aesthetic aspect Price cheap expensive moderate C.1. Clinker and asphalt pavings. Clinkers and asphalt are used very frequently because these types of paving offer good properties in terms of functionality. These pavings easily lend themselves to frequent use and heavy traffic. They also require very little maintenance. Notwithstanding the fact that concrete and clinker manufacturers place products on the market that are to a certain degree porous, we can say that during periods of heavy rain these products do not offer a satisfactory alternative to 100% porous surfaces. What is more, designers increasingly want to distance themselves from products that evoke images of busy roads, queues, etc. C.2 Gravel pavings. A) Benefits and problems Gravel pavings are 100% porous, always colourfast and offer a cost-effective paving solution. However, with frequent use ruts quickly form in this type of paving and pits will always require re-filling. This dramatically reduces functionality. A gravel type is always indicated by a name (e.g. dolomite) and a number which relates to the minimum and maximum calibre of the gravel (e.g. 5/15). With some types of gravel, the fraction of the minimum calibre is extremely small (e.g. dolomite 0/5). If the minimum calibre is 0, we refer to this as dust. The major benefit of such a type of gravel is that the paving material settles by itself because all the cavities in the gravel will be filled in by the dust. This does, however, have its consequences: - Significantly reduces porosity - During dry periods dust will easily be whipped up. - In periods of damp weather, the fine fractions will easily stick to shoes. - Dust from the vicinity sticks to the paving, and is not removed to the substrate because the paving is not very porous, causing the paving to change from yellow to beigebrown in a couple of years. 6

7 These pavings also have a tendency to form pits and ruts, creating a need for regular maintenance. B) Choice of gravel or shingle Shingle (round) Ideal for places used by children (round granules are less painful on contact with bare knees.) Gravel (broken) Make sure you always choose a gravel type that had its origin in hard rock. In this way you will avoid the gravel crumbling over time, thereby forming small fractions. In addition, soft rocks are also more porous, which can lead to the formation of green. Your gravel dealer will provide you with any advice in this respect. without Nidagravel without Nidagravel without Nidagravel C.3 Nidagravel gravel stabilisation By using Nidagravel gravel stabilisation, it is possible to it is to find a solution to the dilemma a to the dilemma of on the on the one one hand a perfectly a porous and colourfast paving and on the and other a functional paving. a paving.. with Nidagravel with Nidagravel with Nidagravel + Perfect stabilisation easily passable on foot or in vehicles, even for WHEELCHAIRS + Ruts and pits are a thing of the past dramatic drop in maintenance + Perfect drainage via the honeycombs the gravel does not turn green. + Weed formation limited by geotextile fewer herbicides + Your paving remains colourfast colour-fast paving + No oil stains pollutant-resistant + Your paving can bear loads of up to 100 tons/m 2 from footpaths to lorry park + Large sheets quick installation 7

8 D. Product description. Nidagravel is manufactured from extruded polypropylene. Nidagravel is chemically inert, resistant against ageing, accidental chemical contamination, microorganisms and rodents. It can also be recycled. The sheets with 37 mm honeycombs allow a gravel type to be used with a diameter of up to 18 mm. One sheet measures 2400 mm by 1200 mm. These dimensions guarantee quick installation. Each sheet is 40 mm in height. Your project will be realised with 5 cm gravel so that the sheets remain invisible. A porous geotextile has been applied to the underside of the sheet. This geotextile was applied for the following reasons: 1- It prevents the gravel from getting beneath the sheets and eventually pushing them up. 2- It prevents the gravel from sinking into the substrate under the influence of the loads on the paving, so that you no longer need to top up the gravel. 3- It slows down a root and weed formation. Attention: weeds do not come out of the ground. Weeds are caused by seeds that fall onto the paving (birds, wind, etc.). In moist ground combined with calciferous stones, these seeds will germinate. Gravel, however, does not provide a good medium. The roots will concentrate in one honeycomb, as it is almost impossible for them to pass through the root sheet. In the next dry period, the weeds will die off as they will experience a sudden water shortage, because in combination with the honeycomb structure gravel drains water perfectly. The geotextile on the base is larger than the actual sheet allowing for an overlap with the adjacent sheet. 8

9 E. Specifications text. Description: Extruded polypropylene sheets with a honeycomb structure used for gravel stabilisation. The honeycombs, with a diameter of 37 mm, have a porous geotextile on the underside. (hot-glued) The product is supplied in sheet form. The sheets are light and pressure-resistant; they are used to give cohesion to granular substrates so that they can allow passing traffic. They are used to strengthen and stabilise ground consisting of gravel or sand. They are highly resistant against aggressive products, microorganisms and rodents. Dimensions: standard sheets (mm): Length x Width: Thickness: Diameter of honeycombs: Other dimensions and thicknesses on request. Colour: 2400 x 1200 mm 40 mm 37 mm milky-white Main physical and mechanical properties: Mass per surface unit: ~ 2 kg/m 2 Resistance to compressibility (failure load) ISO Empty: ~ 40 T/m 2 - Filled: ~ 100 T/m 2 (depending on type of granulate) Resistance to chemical substances: very good Long-term storage: protect against ultra-violet light 9

10 F. Installation. F1. The substrate: practical advice. First, the necessary thickness for the Nidagravel sheets and the foundation layer must be dug out. The thickness of the foundation depends on the load-bearing capacity of the substrate and the anticipated traffic (light or heavy vehicles): When installing the sheets, the most important function is performed by the foundation layer. The foundation is responsible for transferring and spreading the loads to and over a substrate which can vary in strength. It goes without saying, therefore, that not all substrates require the same type of foundation. Nevertheless, we are able to provide some advice: For footpaths and cycle paths: 10 cm gravel (broken limestone or broken concrete e.g. 0-32) covered with several centimetres of fine gravel for levelling. For cars: 20 cm gravel (broken limestone or broken porphyry or broken concrete) covered with several centimetres of fine gravel for levelling If we are working with a broken stone foundation, granulates of a large calibre will often be used (e.g. brokenlimestone 0-32). This foundation is not level enough to lay Nidagravel sheets directly on it. We therefore recommend placing a flattening layer on top of this foundation layer with a gravel type (e.g. broken limestone 1-3) which if necessary must be compacted and then levelled off. 10

11 F2. Edge retainers Special attention must be paid to the edge retainers in order to protect the Nidagravel sheet against lateral mechanical loads. This is especially the case at those points where travelling loads enter the site. The edge retainer has a dual function: - It will make sure that the gravel does not enter the area adjacent to the paving. - It offers protection for the Nidagravel gravel stabilisation sheets. Possible finishes include: Clay or concrete clinkers Aluminium profiles Concrete marginal strips In each case, this marginal strip will protrude at least a couple of cm above the level of the gravel stabilisation sheets. F3. The Nidagravel gravel stabilisation sheets. A) General. One sheet has a surface area of almost 3 m. The geotextile that runs along the two edges of the Nidagravel sheet is placed directly beneath the adjacent sheet. The sheets do not need to be mechanically anchored, since one sheet when filled with gravel will weigh 230 kg. 11

12 Working on edges or holes is child s play. The sheets can be cut with a knife, grinding disc or jigsaw. B) Installation on inclines. The sheets can be placed on slope up to 45 % (or 24 ), without having to fix them. F4 Filling the Nidagravel sheets with decorative gravel. Due to the consolidation of the granulates during the first few days after the paving is put into use, we recommend filling the gravel to 2 centimeters above the sheets. This will keep the level 1 cm above over time. The high-pressure resistance of 100 tonn ieved at the time the sheets are filled with gravel. Until then it is advisable not to allow any travelling loads on the sheets. G. Maintenance of Nidagravel gravel stabilisation. G1. Nidagravel maintenance. Once the paving has been created, we recommend regularly inspecting the top layer (i.e. the layer of 1 to 2 cm that protrudes above the Nidagravel sheets). The purpose of the top layer is to avoid direct contact between travelling loads and Nidagravel sheets and also to make the sheets invisible. In the period immediately after installation, the gravel will sink a little further through natural compaction, which may expose the sheets. In this case the gravel will have to be topped up, for aesthetic reasons but also from a functional viewpoint. With regular use we recommend levelling the top layer occasionally. This can be carried out quickly using a skimmer. 12

13 G2. Weeds. In damp periods, weed seeds will germinate if they land on the gravel paving. This is certainly the case with calciferous stones. However, the presence of the geotextile makes it more difficult for roots to take hold. This means that the roots of weeds will concentrate mainly in the Nidagravel honeycombs. Since the Nidagravel paving is perfectly porous, many weeds will quickly suffer from a lack of water in dry periods, and most will dry out and die. The surviving weeds can easily be removed because the roots are not able to take hold in a gravel base. A broken stone foundation also makes it difficult for weeds to take hold. G3. Salt / snow. In contrast to grass squares, salt does not have a negative effect on gravel paving with Nidagravel. If a snowplough is used, you must make sure that the top layer of gravel is not scraped off. The best approach is to clear the paving to around three cm above the Nidagravel layer, after which salt can be used. G4. Wear / ageing. - Traffic If travelling loads are kept off the Nidagravel sheet by a top layer of gravel, the wear on the Nidagravel sheets will be minimal. Regular inspection is therefore absolutely essential to ensure the paving has a long life. - Weathering Nidagravel is UV-resistant. Nidagravel is insensitive to frost. - Earth - humus If after a number of years the hollow spaces in the gravel become filled in with humus or earth, it may be necessary to replace the gravel. The major advantage of working with Nidagravel is that only the top layer will have to be removed and replaced. This will give you a completely new paving, as it were, at an extremely low cost. 13

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15 H. Contact details. Do not hesitate to contact us should you require a sample of Nidagravel, reference addresses or a DVD containing a project demonstration. Address : - MD

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