Paving element

Abstract

Concrete paving element with an upper and a lower surface, wherein the upper surface of the paving element is provided with a first covering layer which is formed integrally on a sub-concrete, and the lower surface of the concrete paving element is provided with a second covering layer which is formed integrally on the sub-concrete, characterized in that both the first and the second covering layer are provided with a bevelled edge all around.

Description

The invention relates to a concrete pavement element having an upper side and a lower side, wherein the upper side of the pavement element has a first cover layer integrally formed on a sub-concrete and the lower side of the concrete pavement element has a second cover layer integrally formed on the sub-concrete.Such components are known in the prior art and are described, for example, in NO20180329A and JP H03-194004A. The top layer is usually made of cement and a fine aggregate such as crushed gravel, also called grit, fine sand (usually having a grain size of 2 mm or less) and possibly a colorant. This covering layer gives the paving stone the desired appearance and a fine surface structure. The underground concrete has a coarser structure, since it contains not only cement but also coarser grains of rock, such as coarser sand and gravelSuch pavement elements represent an improvement over pavement elements provided with a single covering layer having a limited life, as the pavement wears with use, so that the pavement elements have to be replaced after several years. In order to recycle the pavement elements, they must be broken into fractions of, for example, 4-16 mm and / or 16-32 mm, and the material thus broken may be re-incorporated into new concrete as aggregate. However, this recycling is very energy-intensive, and new raw materials such as cement are again required for the production of new elements. With plaster elements coated on both sides, the service life of the plaster elements is doubled and the energy-roughening recycling is clearly extended.If the covering layer of the pavement element is worn out, the element can be easily turned by a pavementr, for example, to give the pavement element a second life. The respective cover layer therefore preferably covers the entire visible surface of the plaster element.Here, "integrally molded" and "integral component" means that the sub-concrete and the covering layer are joined to each other so that the covering layer can no longer be separated from the sub-concrete without destroying the pavement member.The invention provides an improved pavement element of the kind mentioned in the opening paragraph and is for this purpose characterized in that both the first and the second cover layer are provided with a circular, bevelled edge. It has namely been shown that when laying pavement elements from the prior art, the edges, in particular the edges on the underside of the pavement elements, are frequently damaged. This is not a problem in the initial transfer, since the relevant edge is not visible on the underside. Such damage can also occur unnoticed when the floor is lowered, because friction then occurs at the edges. When pavement elements are turned over, such damage is frequently observed, resulting in significant failure of such pavement elements. By providing pavement elements with edges beveled round on both sides, the aforementioned disadvantages are substantially eliminated.If only a few pavement elements of a road or pavement are worn, it is advantageous if the first and second cover layers on the top and bottom sides of the pavement element are the same. Then, the road image remains the same when the pavement elements are turned over. This also facilitates the laying of new pavement, because the paver does not have to take care of which side needs to be laid at the top. This speeds up the laying process.The cover layer of the component according to the invention preferably has a thickness of 5-15 mm, more preferably 7-12 mm, most preferably 8-10 mm. This provides a structural element having the desired appearance and wear resistance.Between the first and second cover layers, the sub-concrete preferably has a thickness of 3-15 cm, preferably 3-10 cm.The skilled person knows the correct compositions and raw materials both for the sub-concrete and for the outer layer concrete. For example, the first and second facing layers are preferably made of a roof-layered concrete composition consisting of cement, water and inert particulate aggregate, the grain size of the aggregate being not more than 8 mm, preferably not more than 5 mm, and more preferably not more than 3 mm, and most preferably not more than 2 mm.The grain size of the rock grain in the cover layer is preferably at least 0.3 mm, preferably 0.5-8 mm, more preferably 1-5 mm. In practice, concrete components are currently produced, such as concrete clinkers, for example, in which the uppermost layer contains chips having a grain size of 1-3 mm or 2-5 mm.The aggregate is preferably selected from sand and crushed gravel, but may also contain organic material, such as particles of the stalk of elefant grass (miscanthus) or ground stalk. It may also contain, for example, a dye.It is also possible to use a crushed and broken product of calcined clay or natural stone fractions as aggregate for the top layer. Thereby, the pavement element maintains the appearance of a fired clay or natural stone product while maintaining the quality of the concrete structural member without having to fire the pavement element. Ground calcined clay products, also called "ground and / or crushed calcined clay products", are known in the art; for example, chamotte, available in various grain sizes, or ground porcelain may be advantageous.In an economical embodiment, the pavement element is selected from a concrete paving stone and a concrete slab, in particular a sidewalk slab or a terrace slab.Preferably, the dry fabric-based pavement element comprises 60-90% aggregate and 40-10% cement, preferably from 75-85% aggregate and 15-25% cement, and most preferably from 80% aggregate and 20% cement. At these ratios of grit and cement, a desired coating is achieved.The sides of the pavement elements may have one or more spacing lugs, preferably extending from bottom to top. These spacer cams ensure a fixed spacing between pavement elements laid next to each other. Such spacing cams are described, for example, in NO20180329A and EP3153625.The production of prior art pavement elements is described, for example, in EP4257315A and EP2055457A using matrices having a solid straight bottom. The pavement elements of the invention are advantageously obtained by a manufacturing method comprising the steps of: a. incorporating a first layer of a wet-faced concrete composition into a matrix defining the contours of the floor and sides of the structural member to form the first cover layer, the floor of the matrix being shaped to form a circumferentially beveled edge in the first cover layer incorporated into the matrix; b. applying a layer of wet-faced concrete sub-composition to the first over-concrete composition applied in step a. to form the concrete sub-composition; c. compacting the concrete layers incorporated in steps a. and b. after step b; d. applying a second layer of wet-faced concrete composition in the matrix to the concrete compacted in step c; e. compacting the product formed in step d in the die; f. drying the product compacted in step e.In step a., earth-moist concrete, i.e. concrete with a water content of typically 8-12% by weight, is introduced into a die. This may be a so-called arch typically used in the production of concrete paving stones or a tile press as known for the production of pavement and terrace slabs may be used. In the production of concrete paving stones according to the invention, the paving element is produced in the same way as conventional concrete paving stones are produced, with the change that a first covering layer is first cast into the die, wherein the circumferentially beveled edges are formed. Thus, a plurality of matrices can be placed side by side on a common base element, e.g. a plate or a wood board, and the matrices provided with a layer of a wet-earth coated concrete composition by a first filling carriage.The side walls of the die are advantageously shaped in such a way that one or more spacer lugs are formed on the side walls, which preferably extend vertically, i.e. from bottom to top. For this purpose, the side walls of the die may have vertically extending projections.In step b., the sub-concrete composition can then be poured into the matrices, e.g. with a second filling truck. Compositions for underground concrete are known. A suitable composition is obtained, for example, by mixing 350 kg of sand, 500 kg of gravel, 300 kg of cement, 100 kg of stone flour and 170 l of water, optionally supplemented by vegetable fibre material such as Miscanthus. However, there are several concrete recipes which are also suitable and known to the skilled person.In step c., the cast material is thickened or compacted, for example by vibrating the die or by briefly applying pressure under the action of a pressure plate, for example a knife, blade or punch, whereby the cast material "sets". This creates space on the upper side of the die for the application of the second layer, which is applied in step d.In an attractive embodiment, step a. comprises, prior to introducing the first layer of the wet-to-the-earth coating concrete composition into the die, introducing an insert having preformed slopes into the die. By casting the first layer of the wet-to-the-earth coating concrete composition, the beveled edges are thus formed.In step c. the poured material is preferably compacted to a volume of 80-90% of the volume of concrete material after step b. before a second layer of earth-moist concrete composition is applied in step d.After step d., the product obtained is further compacted, for example by a subsequent lowering process by shaking or compacting. The compaction is preferably carried out using a pressing plate (for example a knife, blade or punch) which is shaped such that a beveled edge is formed all around in the second cover layer.The press plate is preferably placed under pressure on the second coating.This step can be carried out with a striking press which exerts a high pressure on the shaped part and gives it the desired density. The compaction is preferably carried out in such a way that the volume decreases by 2-5%.Preferably, the shaped product is removed from the die before the drying step, e.g. by lowering a common bottom element of a plurality of dies, whereby the obtained dies can be supported by the bottom element and placed in a drying chamber. In the production of paving stones, wood boards are generally used for this purpose.The product is then dried in step f. to obtain a cured component according to the invention. The drying is carried out under known conditions for drying concrete products. These conditions typically include a temperature of about 25°C and a high humidity of up to 100% which are known to those skilled in the art for drying concrete products.In particular in the case of a colored coating, the matrices removed from the matrices can be subjected to a rinsing treatment, preferably with water. The surface of the size is rinsed with water, whereby any cement residues which cause grey mist are removed and the size thus obtains its fresh color. This rinsing can be effected, for example, by slightly tilting the common floor element on which the mouldings rest and subsequent spraying, followed by tilting in the opposite direction and re-spraying. After rinsing, the moldings are dried to give the end product, the plaster element of the invention.In an advantageous embodiment, the die has a height-adjustable base plate, as is known from an existing tile press known in the art. Thus, in the method, in particular for producing a tile product, the die has a base plate which is height-adjustable in the die and becomesin step a. the height of the die is adjusted to the intended thickness of the first coating, and the die is flattened on the upper side after the introduction of the first coating concrete composition in step a. in such a way that a first coating having a uniform thickness is obtained;in step b. the height of the die is adjusted to the intended thickness of the sum of the first cover layer obtained in step a. and the sub-concrete layer, and the die is leveled on the upper side after the sub-concrete composition has been introduced, namely in such a way that a layered intermediate product having a cover layer of uniform thickness and a sub-concrete layer of uniform thickness is obtained on the upper side;In step d. the height of the die is adjusted to the desired thickness of the sum of the concrete layers compacted in step c. and the second outer layer, and the die is flattened on the upper side after pouring out the second outer layer concrete composition.In this embodiment, the pavement element is made in the same manner as conventional tiles, with the variation that a second coating is applied to the sub-concrete. For this purpose, after the usual compacting step c. in step d. space is possibly left in the die by adjusting the bottom of the die to the correct height, whereupon the die is filled with covering layer material. If the material has set to such an extent that the setting already provides sufficient space for the second layer, further setting of the die base may no longer be necessary. After settling, the material is again compacted, preferably using a pressing plate as described above.ExamplesComposition of the subconcrete (in % by weight)36% 0 - 2 mm sand,26% broken ballast 2-8 mm,21% Comminuted construction debris 0-12 mm,15% cement, cement, cement, and cement,2% fly ash, fly ash, fly ash, and fly ash,The sub-concrete can optionally be supplemented with organic additives, such as Miscanthus, in an amount of, for example, 0.2-0.4%.Composition of the topcoat concrete (in wt %)40% 0 - 2 mm sand,41% Limestone split 2 - 4 mm,17% cement, cement, cement, and cement,2% Lime flour.With the above concrete compositions, bricks and bricks of the following sizes are prepared by standard conventional equipment under conventional conditions.Tiles: thickness (cm): 4.5; 5; 6; 7 and 8.Size (cm): 30 x 30; 15 x 30; 20 x 20; 15 x 20; 50 x 50 and 40 x 60.Stones: thickness (cm): 7; 8 and 10.Size (cm): 21 x 10.5; 10.5 x 10.5; 21 x 7; 21 x 5; and 20 x 5.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP H03-194004A

[0002] EP 3153625

[0016] EP 4257315A

[0017] EP 2055457A

[0017]

Claims

A concrete pavement element having an upper and a lower surface, wherein the upper surface of the pavement element is provided with a first cover layer integrally formed on a sub-concrete, and the lower surface of the concrete pavement element is provided with a second cover layer integrally formed on the sub-concrete, characterized in that both the first and the second cover layers are provided with a circumferentially chamfered edge.Concrete pavement element according to claim 1, characterized in that the first and the second cover layer are the same on the top and bottom sides of the pavement element.Concrete pavement element according to claim 1 or 2, characterized in that the thickness of the first and second cover layer is 5 - 15 mm, preferably 7 - 12 mm, particularly preferably 8 - 10 mm.Concrete plaster element according to one of the preceding claims, characterized in that the sub-concrete between the first and second cover layers has a thickness of 3 - 15 cm.A concrete pavement element according to any one of the preceding claims, wherein the first and second cover layers are made from a roof layer concrete composition comprising cement, water and inert particulate aggregates, wherein the particle size of the aggregates is 8 mm, preferably not more than 5 mm, more preferably not more than 3 mm and most preferably not more than 2 mm.Concrete pavement element according to any of the preceding claims, selected from a concrete pavement stone and a concrete slab, in particular a sidewalk slab.A concrete pavement element according to any preceding claim, manufactured by a method comprising the steps of: a. placing a first layer of a wet-faced concrete composition in a die defining the contours of the floor and sides of the structural member to form the first coating; b. applying a layer of wet-faced concrete composition to the first super-faced concrete composition applied in step a. to form the sub-concrete; c. compacting the concrete layers placed in steps a. and b. after step b; d. in the die, on the concrete compacted in step c. applying a second layer of wet-faced concrete composition; e. compacting the product formed in step d in the die; f. drying the product compacted in step e.The concrete pavement element of claim 7, wherein in step a. prior to introducing the first layer of the wet-to-the-earth coating concrete composition into the die, an insert floor element having preformed beveled edges is introduced into the die.A concrete pavement element according to claim 7 or 8, wherein in step c. the concrete is compacted to a volume of 80-90% of the volume of the concrete material after step b.Concrete plaster element according to one of Claims 7 to 9, characterized in that, in step e. the compaction takes place under the action of a press plate which is shaped in such a way that it forms a circumferentially beveled edge in the second covering layer.Concrete pavement element according to any of claims 7-10, wherein the press plate is laid under pressure on the second cover layer.Concrete pavement element according to any of claims 7-11, wherein in step e. the compaction is performed such that the volume decreases by 2-5%.Concrete plaster element according to one of claims 7 to 12, wherein the matrix has a base plate movable vertically within the matrix, and - in step a. the height of the matrix is adjusted to the intended thickness of the first coating, and the matrix is flattened on the upper side after the introduction of the first coating concrete composition in step a., namely in such a way that a first coating having a uniform thickness is obtained; - in step b. the height of the matrix is adjusted to the intended thickness of the sum of the first covering layer obtained in step a., and the sub-concrete layer and the matrix are flattened on the upper side after the introduction of the sub-concrete composition, namely in such a way that a layered intermediate product having a covering layer having a uniform thickness and a sub-concrete layer having a uniform thickness is obtained; in step d. the height of the die is adjusted to the nominal thickness of the sum of the concrete layers compacted in step c. and the second cover layer, and the die is flattened on the upper side after the introduction of the second cover layer concrete composition.