DE102017126345A1 - Reinforcement of 3D printed concrete bodies - Google Patents

Abstract

The invention relates to a method for producing a component (1) of hardenable material, wherein in a first method step at least one layer (2, 3) of the material is printed in one direction in a 3D printing method, in a second method step at least one reinforcing element in the Position (s) (2, 3) introduced, and the two process steps to the completion of the component (1) are repeated cyclically. Known such methods have the disadvantage that no large-area reinforcement is possible. The task of designing a method so that its reinforcement can withstand high loads is achieved in that each reinforcing element as in the direction of the layers (2, 3) extending strand (4) is formed with a perpendicular to the layers (2, 3) oscillating, periodic pattern and extending over at least two layers (2, 3). Furthermore, a corresponding component is provided.

Description

The invention relates to a method for producing a component made of hardenable material according to the preamble of claim 1 and to a corresponding component according to the preamble of claim 8.

Even in industrialized countries, the construction of concrete structures is still largely based on craftsmanship. In principle, such structures or parts of these structures can be produced in two different ways. On the one hand you can work with formwork on site, which are then poured with so-called in-situ concrete, with reinforcing reinforcements can be introduced in load-bearing parts. Then wait until the concrete is partially or fully cured, after which the formwork can be removed, cleaned and then reused. The process is time consuming and requires the deployment of a large number of site workers.

Another method is to pour the concrete parts of the structure beforehand in a factory, so to create as prefabricated components and deliver as such to the site. Not only walls or floor components, but entire room cells can be manufactured as prefabricated concrete parts and delivered to the construction site. This method is less expensive, but has a high degree of standardization and is therefore suitable only for the production of a large number of identical or similar structures or for very large structures which require a large number of identical spatial cells. An individual design is again possible only with high cost.

On the basis of these known techniques, a so-called additive manufacturing process has recently emerged in the manufacture of concrete structures, namely the 3D printing of concrete. Here, the building is designed on a computer and the data is then forwarded to a printer. The printer is a fully automatic gantry robot that is larger than the building or part of the building to be constructed. Instead of gantry robots, multi-axis or console robots or mobile robots can also be used. This has a print head and concrete feeds, via which the in-situ concrete is fed to the print head. This printhead then pours the structure to be created or its walls in several layers on top of each other, each layer has a thickness between 1 and 10 cm. The concrete used here is viscous enough to keep the stability until curing, or at least until hardening. In this way, the print head pours a wall in a plurality of layers arranged one above the other.

The problem is the creation of buildings by means of 3D printing process the reinforcement of the walls. In principle, finished steel frameworks or similar reinforcing elements can be incorporated, but this can only take place when the wall is at least partially printed, since otherwise the reinforcing elements would disturb or prevent the movement of the printing head. If one waits, however, until the wall is completely printed, the lower layers of the concrete are already completely or largely cured, so that subsequently no reinforcing elements can be introduced more.

The CN 106313272 A describes a 3D printing process for the manufacture of concrete structures where the concrete is reinforced with fibrous materials and where two printheads are used, one of which prints the concrete and the other steel elements. In this case, the introduced steel elements each overlap two superimposed layers of concrete and connect them thus.

The disadvantage here is that only a selective connection of adjacent concrete layers is possible, but no large-area reinforcement, as in classical manufacturing method, e.g. with steel mats is possible.

It is an object to provide a method for producing a component made of hardenable material, in particular concrete, in such a way that its reinforcement withstands high loads.

This problem is solved by the characterizing features of claim 1.

Furthermore, the object is to provide a corresponding component. This object is solved by the characterizing features of claim 8.

• 1: Einen Querschnitt durch ein teilweise erstelltes Bauteil nach dem erfindungsgemäßen Verfahren;
• 2: einen Querschnitt durch eine alternative Ausführungsform des Verfahrens;
• 3: einen Querschnitt durch eine weitere alternative Ausführungsform des Verfahrens.

Some embodiments of the invention will be explained in the following with reference to the accompanying drawings. These show:

• 1 : A cross section through a partially created component according to the inventive method;
• 2 a cross-section through an alternative embodiment of the method;
• 3 Fig. 3: a cross section through a further alternative embodiment of the method.

To carry out the method according to the invention - in so far as known per se - a 3D printer, for example in the form of a fully automatic gantry robot, which can print a wall or a whole room cell or other vertical units of a building in successive layers. In 1 a component in the formation process is shown, which consists of several layers of concrete printed on one another, wherein two middle layers by way of example with the reference numbers 2 and 3 are provided and wherein the uppermost position is still in the formation process - ie during the printing process - is.

In carrying out the process, the following process steps repeat cyclically until the completion of the structure.

In a first process step in each case one layer 2 or. 3 of the curable material, in this case concrete, applied in a 3D printing process and in a second process step becomes a strand acting as reinforcing elements 4 in the layers 2 or. 3 brought in. Both process steps are until the completion of the component 1 cyclically repeated. Every strand 4 exists at the in 1 illustrated embodiment of a rigid material, in particular metal, for example steel, and can in the not yet cured layers 2 or. 3 of the curable material are inserted after they have been printed.

Every strand 4 extends over at least two layers 2 or. 3 and the strands 4 extend in the direction of the layers 2 or. 3 with a perpendicular to the layers 2 or. 3 oscillating periodic pattern. In the illustrated embodiment, each strand extends 4 over two layers 2 or. 3 and the periodic training corresponds to a rectangular course. As 1 can be seen, are the oscillating in the manner of a rectangular course strands 4 within the layers 2 or. 3 of the component 1 arranged so that the phases of two superimposed strands 4 alternate. In this way, there is an overlap area in which the rectangular region of a strand extending from a lower to the upper layer 4 with the lower rectangular area of the overlying strand 4 covered or even exceeds, so that the intervening concrete a power flow between adjacent strands 4 enabling a stable reinforcement and a high stability of the component 1 is produced. In this approach, each strand 4 out of phase with the underlying strand 4 in the layers 2 or. 3 pressed.

In an alternative embodiment of the method, as in 2 is shown, the strands exist 4 not of a rigid material, but of a flexible material, such as a tensile thread, which may consist of a plastic, such as Kevlar. Due to the flexibility of the material here is an impression in the layers 3 or. 3 the already relatively hard but still plastic concrete mortar of the layers 2 or. 3 not possible. Rather, one uses oneself here, as in 2 is shown, for pressing in each case a rectangular loop of the strand 4 a guide pin 5 which consists in the illustrated embodiment of two adjacent pins whose distance to the width of the rectangle of the periodic course of the strand 4 equivalent. Using this guide pin 5 may be consecutive components of the rectangular course of the thread 4 in the still soft concrete mortar of the layers 2 or. 3 be pressed. Also in this embodiment are superimposed strands 4 of the reinforcement material preferably inserted in phase opposition, so that there is a partial overlap or overlapping of superimposed strands 4 resulting in increased stability in the region of adjacent parts of the strands after curing of the concrete.

In a further alternative embodiment, as in 3 is shown, a sinusoidal shape is chosen instead of a rectangular course of the periodicity of the strands. At the in 3 illustrated embodiment, the strands 4 also made of flexible threads, so that here too a guide pin 5 for impressing the strands 4 in the layers 2 or. 3 of the component 1 necessary is. In this embodiment too, the strands laid one above the other in an opposite phase overlap or overlap 4 , so that by their proximity in the overlapping region takes place a particularly high power transmission of adjacent strands and thus adjacent layers.

Further alternative embodiments are conceivable. So the periodic pattern, as in the 1 and 2 shown to be rectangular, or as in 3 shown to be sinusoidal. It can also be triangular or have a different periodicity. In all embodiments, instead of a rigid material, as in 1 is shown, also a flexible material, so eg a thread, are used, as it is in the 2 and 3 is shown.

Instead of concrete, the invention can also be realized with thixotropic geopolymer. Preferably, the lateral spacing of overlapping strands is at most five times the diameter of each reinforcing element. In this way, a particularly intimate connection and a particularly good flow of force between adjacent reinforcing elements by the intervening concrete.

As can be seen from the figures, the superimposed, periodic reinforcement elements overlap, wherein in the overlapping region they have the smallest possible lateral distance from one another, preferably a lateral distance which is less than the maximum lateral extent, ie half the periodicity, of each reinforcement element 4 , but preferably still significantly lower. Due to this small lateral spacing of superimposed reinforcement elements 4 In the overlapping region, an optimal force flow is ensured by the intervening, mediating concrete, and thus the highest possible stability of the reinforcement, which approaches the stability of a reinforcing steel mat, is achieved.

The inventive method and the thus created component have the advantage of a much more intimate connection of the reinforcing elements or strands 4 and a much firmer reinforcement, because of the strands 4 the same effect can be achieved as in the classic concrete casting by using a steel mat. The introduction of strands according to the invention makes it possible, even in 3D printing, where a continuous steel mat can not be used, to achieve the same or similar strength values as when using continuous structural steel mats in the concrete casting process.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• CN 106313272 A [0006]

Claims (14)

Method for producing a component (1) from a hardenable material, wherein in a first method step at least one layer (2, 3) of the material is printed in one direction in a 3D printing method, in a second method step at least one reinforcing element is in the layer (s) (2, 3), and the two process steps are repeated cyclically until completion of the component (1), characterized in that each reinforcing element as in the direction of the layers (2, 3) extending strand (4) with a perpendicular to the Layers (2, 3) oscillating, periodic pattern is formed and extends over at least two layers (2, 3). Method according to Claim 1 , characterized in that two superimposed strands (4) have the same periodicity with reversed phase and overlap in this way within a layer (2, 3). Method according to Claim 1 , characterized in that the hardenable material is concrete. Method according to one of the preceding claims, characterized in that the strands (4) made of a rigid material, in particular metal, in particular steel and are inserted into the uncured layers (2, 3) of the curable material. Method according to one of Claims 1 to 3 , characterized in that the strands (4) made of a flexible material, such as a tensile thread, eg made of Kevlar, and with the aid of a guide pin (5) in the uncured layers (2, 3) of the curable material are inserted. Method according to one of the preceding claims, characterized in that the periodic pattern is rectangular or triangular or sinusoidal. Method according to one of Claims 2 - 6 , characterized in that the lateral distance of overlapping strands (4) is at most five times the diameter of a reinforcing element (4). Component (1) made of a reinforced material, which has a multiplicity of layers (2, 3) produced in a 3D printing process and reinforcing elements which connect these layers (2, 3) to one another, characterized in that each reinforcing element is in the direction of the layers (2, 3) extending strand (4) is formed with a perpendicular to the layers (2, 3) oscillating, periodic pattern and extending over at least two layers (2, 3). Component after Claim 8 , characterized in that two superimposed strands (5) have the same periodicity with reversed phase and overlap in this way within a layer (2, 3). Component after Claim 8 or 9 , characterized in that the material is concrete. Component according to one of Claims 8 to 10 , characterized in that the strands (4) made of a rigid material, in particular metal, in particular steel. Component according to one of Claims 8 to 10 , characterized in that the strands (4) made of a flexible material, such as a tensile thread, eg Kevlar consist. Component according to one of Claims 8 to 12 , characterized in that the periodic pattern is rectangular or triangular or sinusoidal. Component according to one of Claims 9 - 13 , characterized in that the lateral distance of overlapping strands (4) is at most five times the diameter of a reinforcing element (4).

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