US20150368902A1

US20150368902A1 - Method for producing a multi-layered reinforced concrete element

Info

Publication number: US20150368902A1
Application number: US14/766,148
Authority: US
Inventors: Rolf Roers; Haval Khaffaf; Michael LOOF; Achim Symannek
Original assignee: Covestro Deutschland AG
Current assignee: Covestro Deutschland AG
Priority date: 2013-02-15
Filing date: 2014-02-10
Publication date: 2015-12-24
Also published as: EP2956283A1; CN104981330A; RU2015139040A; EP2956283B1; CN104981330B; WO2014124886A1; EP2767373A1; MX2015010227A

Abstract

The invention relates to a method for producing a multi-layered reinforced concrete element (10), comprising at least one first concrete wall section (11) in composite with a reinforcement body (13), wherein the concrete element (10) comprises an insulating layer (14), which lies at least indirectly against the first concrete wall section (11), and wherein the reinforcement body (13) is formed at least partially so as to protrude from the first concrete wall section (11) and so as to penetrate the insulating layer (14), involving the following steps of: preparing the composite of the first concrete wall section (11) with the reinforcement body (13) that at least partially protrudes therefrom; preparing a fill (15), in particular in an upwardly open fill container (23); arranging the first concrete wall section (11) with the reinforcement body (13) arranged thereon over the surface of the fill (15) such that a protruding section (13′) of the reinforcement body (13) is arranged on the underside of the first concrete wall section (11) and is only partially immersed into the fill (15) such that a vertical free space (16) remains between the surface of the fill (15) and the underside of the first concrete wall section (11); filling the free chamber (16) with a reaction mixture, and curing the reaction mixture (14) so as to form the insulating layer (14).

Description

The invention relates to a method for producing a multi-layered reinforced concrete element, the multi-layered reinforced concrete element having at least one first concrete wall in composite with a reinforcement body, the concrete element comprising an insulating layer bearing at least indirectly against the first concrete wall, and the reinforcement body being designed to project at least partially out of the first concrete wall and to penetrate the insulating layer.

PRIOR ART

Precast concrete parts play an important role in the building industry. In view of increasing energy efficiency requirements, precast concrete parts have for some years been equipped at the factory with integrated insulating layers, this referring particularly to walls and ceilings made from reinforced concrete with core insulation. Mostly, however, in the almost completely automated production process, insulating board stock composed particularly of mineral wool and polystyrene is introduced by hand.
EP 1 010 828 B1 shows a more advanced production of a precast wall part with an inner shell and outer shell made from concrete and connected to one another via bearers of a reinforcement body. After the production of the outer shell, PU foam is applied to its inside which points upward for the purpose of applying the PU foam. The complementary concrete shell is thereafter produced by dipping into a concrete bed and by subsequent setting. A defined cavity for the PU foam body is in this case not provided, and subsequent filling with further concrete takes place onto an undefined PU insulating layer surface. The not yet set PU foam body, which is applied as a reaction mixture, is distributed by means of an air stream. The height of the cured foam is in this case derived from the applied height of the reaction mixture, the height of the latter being determined in turn by the speed of application, with a given reaction time, and having irregular topography. A structurally geometric limitation of the cavity is therefore not provided, the disadvantage of this being that an insulating layer of defined thickness cannot be formed.
A similar method is disclosed in EP 1 106 745 A2. In this case, a method for producing a prefabricated ceiling element as a finished component is likewise described, two disks of reinforced concrete being spaced apart from one another by means of a plurality of lattice bearers, the lattice hearers being concreted into the respective disk, the end portions surrounding at least the longitudinal bars with welded-on strut junction fittings, and the space between the disks being filled completely with foamed polyurethane. The cavity arising between the two disks is filled with in-situ polyurethane foam as early as during production. The cured polyurethane layer is in this case intended to assist the structurally static function of the lattice hearers and of the concrete disks. In this case, furthermore, it is specified that such manufacture can advantageously take place efficiently in production on a circulating pallet installation. The required heat insulation can in this case be set via the thickness of the polyurethane layer, but the disadvantage is that the prefabricated ceiling element can be completed only in a sandwich type of construction, since it is absolutely necessary to have two concrete disk elements spaced apart from one another in order to define a cavity for introducing the reaction mixture for forming the polyurethane layer.

DISCLOSURE OF THE INVENTION

The object of the present invention is to provide an improved method for producing a multi-layered reinforced concrete element, and, in particular, the object of the invention is to be able in a flexible way to form the insulating layer from a PU foam preferably with different thicknesses.
The object on which the invention is based is achieved by means of a method as claimed in claim 1, advantageous refinements arising from the subclaims.
According to the invention, a method for producing a multi-layered reinforced concrete element is provided, the concrete element comprising a first concrete wall in composite with a reinforcement body and having an insulating layer bearing at least indirectly against the first concrete wall, the first concrete wall being connected to the insulating layer and, in particular, to a second concrete wall via a reinforcement body, in particular a GFRP or steel reinforcement body. The method according to the invention in this case comprises the steps mentioned below:
As the first step, the provision of the first concrete wall having a reinforcement body may take place, the reinforcement body being cast partially into the first concrete wall. This may take place by the casting and setting of the first concrete wall in a casting mold, during casting one portion of the reinforcement body being cast into the concrete wall (hereafter: cast-in portion), and a further portion of the reinforcement body being capable of projecting out of the first concrete wall (hereafter: projecting portion). This is then followed by the step of arranging the first concrete wall and the reinforcement body arranged on it with a vertical spacing from the underside of the first concrete wall via heaped loose material, in particular silica sand, which has previously been introduced into a heaping container and, for example, has been shaken or smoothed out. The projecting portion is in this case arranged on the underside of the first concrete wall and penetrates into the heap, and, in particular, the heap may subsequently be shaken. A predefined free space in this case remains between the surface of the heap and the underside of the first concrete wall. This is followed by filling up the free space with a reaction mixture to form polyurethane foam which constitutes an insulating layer. The step of curing the insulating layer subsequently follows. In a final step, the concrete wall, together with the reinforcement body and with the polyurethane insulating layer cured on this composite, can be removed from the heap and, in particular, be freed of the material of the heap.
The essence of the invention is, in particular, that the concrete wall provided with the reinforcement body, for example with integrated metallic lattice bearers or GFRP ties to form the reinforcement body, is placed upside down, that is to say with the reinforcement body pointing downward, over a preferably shakeable heaping container or the like, in which the heap of flowable solids, in particular of a fine-grained granulate, such as, for example, silica sand, is provided. The filling height of the heap or the height at which the concrete wall is held over the surface of the heap may be stipulated, as desired. Thus, the insulating layer can be formed in a most highly flexible way with different thicknesses. The thickness of the insulating layer may amount, for example, to a value of 2 cm to 40 cm, preferably of, for example, 5 cm to 30 cm and especially preferably of, for example, 10 cm to 25 cm, since these thicknesses can be foamed especially well with a reaction mixture. Reaction mixtures of polyol and isocyanate are especially suitable for the production of polyurethane insulating layers, although the insulating layer may comprise any further insulating material, for example even a phenol resin foam.
The reinforcement body does not have to be produced in one piece, and, for example, individual, preferably glass fiber-reinforced polymer bars or cages may also form the reinforcement body. Thrust pegs, as they may be referred to, are also known, and therefore the reinforcement body may also be constructed, in particular, from a thrust peg system composed of steel elements or fiber-reinforced polymer elements which form the thrust pegs.
The filling of the free space with the reaction mixture may take place by means of a flexible casting system, for example by means of a casting rake system, with a rigid or with an oscillating casting head or with a casting mandrel which is such that it can be moved between the concrete element and the heap surface in spite of the presence of the reinforcement body. Preferably, however, casting may also take place from the side, and the reaction mixture may run into the free space. The term “casting” in this case likewise embraces any type of spraying or injection of the reaction mixture.
The heap may be formed, in principle, by any type of flowable solids and may also comprise mixtures of different solids. The heap should in this case be suitable for forming a barrier for the reaction mixture, in order thereby to exert a shape-forming action, while the reaction mixture, which comprises, in particular, polyol and isocyanate as components, can fill with foam to a vertically defined height the free space which, for example, extends flat horizontally.
For this purpose, in particular, silica sand has proved suitable. The hollow space thus provided forms a defined cavity with an essentially flat extent, extending parallel to the first concrete wall, between the surface of the heap as the lower boundary and the underside of the first concrete wall as the upper boundary, and this hollow space may be filled, in particular by means of a distribution system, over its entire area with flowable reaction mixture or with another at least phasedly flowable mixture, in order, after curing, to form the insulating layer.
Subsequently, the second concrete wall may be cast onto the element produced or the insulated first concrete wall may be dipped into the still fresh (non-set) second concrete wall, so that a reinforced concrete sandwich element with two concrete walls and with the insulating layer, in particular PU hard foam core insulation, lying between them is obtained as a final component.
It has been shown that the use of polyurethane hard foam insulation, which can be introduced as a liquid reactive mixture into the free space, makes it possible to have marked advantages in terms of more efficient automated production and/or a more energy-efficient and more slender component. By means of the method according to the invention, the automated introduction of a polyurethane insulating layer as a liquid reaction mixture can be made possible and can be integrated into the overall production process.
In a first preferred refinement, after the curing of the insulating layer the following method step takes place: insertion of the first concrete wall together with the reinforcement body into a casting mold, the projecting portion and the insulating layer being arranged underneath the first concrete wall. The filling of the casting mold with concrete may subsequently take place, but preferably the insertion of the first concrete wall into the already reinforced and freshly concreted second wall may be carried out.
The casting of the concrete for the second wall therefore usually takes place before the insertion of the already set first wall. The second concrete wall is thus obtained, into which the projecting portion of the reinforcement body is likewise at least partially cast. In this refinement, therefore, the projecting portion projects downward. The casting mold is delimited upwardly by the concrete wall. The free space is thus filled up in a targeted manner, depending on the quantity of liquid concrete which is introduced into the casting mold.
In this case, selectively, by the free space being filled up completely, the second concrete wall may also be formed in such a way that the second concrete wall bears at least indirectly against the insulating layer. There is therefore then no longer any interspace present in the finished product between the second concrete wall and the insulating layer. Alternatively, however, there may also be provision whereby the free space in the casting mold between the bottom of the casting mold and the insulating layer is filled only partially with liquid concrete, so that an interspace remains between the insulating layer and the second concrete wall. Such an interspace may, for example, be filled up with concrete later on the building site.
In a second preferred refinement, there is provision whereby, after curing, the composite of the insulating layer and of the first concrete wall, together with the reinforcement body, is inserted into the casting mold, the projecting portion of the reinforcement body and the insulating layer being arranged above the first concrete wall. In this case, the insulating layer can form the bottom of the casting mold thus provided. The result of subsequently filling up this casting mold with liquid concrete will then be that the second concrete wall is necessarily brought at least indirectly into bearing contact with the insulating layer. Preferably, for this method step, too, the composite of the first concrete wall with the reinforcement body and of the insulating layer is dipped into an already concrete-filled casting mold, with the insulating layer pointing downward, and the concrete is subsequently set. In this refinement, there is no interspace generated between the second concrete wall and insulating layer.
Indirect bearing in this case also means a set-up in which a further material ply, for example an insulating foil, is provided between the concrete wall and the insulating layer bearing against it. However, should a free, in particular air-filled interspace be provided between two layers, the two layers are no longer in bearing contact with one another.
During the filling-up operations, the concrete walls, which, in principle, may be plate-shaped, are oriented essentially horizontally.

PREFERRED EXEMPLARY EMBODIMENTS OF THE INVENTION

Further measures which improve the invention are illustrated in more detail below, together with the description of preferred exemplary embodiments of the invention, with reference to the figures in which:

FIG. 1 shows the first part of the production method in several steps,

FIG. 2 shows the second part of the production method in a first refinement in several steps, and

FIG. 3 shows the second part of the production method in a second refinement in several steps.

FIG. 2 c shows a finished reinforced concrete element 10 which has been produced by means of a method according to the invention. The reinforced concrete element 10 comprises a first concrete wall 11 arranged on top and a second concrete wall 12 spaced apart from this. Between the two concrete walls 11 and 12, an insulating layer 14 is provided. The insulating layer 14 hears against the first concrete wall 11, and a free interspace 20 is formed between the insulating layer 14 and the second concrete wall 12.
FIG. 3 c shows an alternative reinforced concrete element 10. This corresponds largely to the set-up of the reinforced concrete element according to FIG. 2 c, the free interspace 22 being dispensed with. In that respect, then, the insulating layer 14 also bears against the second concrete wall 12. For example, plastic films or other material plies may be arranged between the insulating layer 14 and the concrete walls bearing against it.
In the refinement according to FIG. 2 c, a reinforcement body 13 in the form of a steel reinforcement cage, which can be seen in the interspace 20, is shown. In FIG. 3 c, the reinforcement body 13 is surrounded completely by concrete or the insulating layer 14 and therefore cannot be seen.
With reference to FIG. 1, then, a first part of the production method according to the invention is described. In FIG. 1 a, the reinforcement body 13 is inserted in a first casting mold 17. The first casting mold 17 is then partially filled with liquid concrete 22. The concrete subsequently sets to form the first concrete wall 11, see FIG. 1 b. A portion 13″ of the reinforcement body 13 is then cast into the first concrete wall 11. Another portion 13′ of the reinforcement body 13 projects out of the first concrete wall 11.
Subsequently, the element obtained, composed of the first concrete wall (11) and of the reinforcement body (13), is overturned, so that the projecting portion 13′ is arranged on the underside of the first concrete wall 11. The reinforcement body 13 is then dipped, virtually upside down, into a heap 15 of defined depth which is introduced into a heaping container 23 (see FIG. 1 c). The heap 15 is formed by sand, in particular by silica sand. However, only the reinforcement body 13 is dipped with its projecting portion 13′ into the heap 15. The first concrete wall 11 remains completely above and is arranged so as to be spaced from the heap 15. A vertical free space 16 thus remains between the first concrete wall 11 and the heap 15 in the heaping container 23, see FIG. 1 d.
The heap 15 may be shaken by means of a shaking device. Particularly after the dipping of the reinforcement body 13, the shaking of the heap 15 is expedient, in order thereby to distribute the heap as uniformly as possible and to obtain as planar a surface as possible.
The free space 16 is then filled completely with a flowable reaction mixture, in the present example PU foam composed of polyol and isocyanate. At the same time or thereafter, the reaction mixture becomes solid and forms a composite of the insulating layer 14 with the first concrete wall 11 and of the reinforcement body, see FIG. 1 e. FIG. 1 f, then, shows the intermediate product which comprises the first concrete wall 11, the insulating layer 14 bearing against it and the reinforcement body 13.
With reference to FIGS. 2 (first refinement) and 3 (second refinement), then, the further processing of the inlet mediate product according to FIG. 1 f into the finished reinforced concrete element 10 is explained. However, depending on the application, the intermediate product according to figure if may also even constitute a finished reinforced concrete element.
In the first refinement, the intermediate product is inserted into a second casting mold 18, see FIG. 3 a. The reinforcement body 13 is inserted, with its projecting portion 13′ downward, into the second casting mold 18. Spacers, not illustrated, can ensure that the reinforcement body 13 has, in principle, a certain spacing from the bottom 19 of the casting mold 18. It can be seen in FIG. 2 b that a free space 21 is then formed between the insulating layer 14 and the bottom 19 of the casting mold 18. The projecting portion 13′ of the reinforcement body 13 is arranged therein. This free space 21 is then filled up at least partially with concrete 22. An interspace 20 remains, since the free space 21 is only partially filled up. However, it is also possible that the free space 21 is filled up completely. The second concrete wall 12 is then also thereby brought into bearing contact with the insulating layer 14.
In the second refinement, the intermediate product according to figure if is inserted into the second casting mold 18 such that the projecting portion 13′ of the reinforcement body 13 points upward, and so that the first concrete wall 11 is arranged underneath the insulating layer 14, see FIG. 3 a. FIG. 3 b, then, shows the intermediate product according to FIG. 1 f inside the second casting mold 18. The first concrete wall 11 lies on the bottom 19 of the second casting mold 18. The casting mold 18 is then filled up with concrete 22 from above. On account of gravity, the concrete 22 introduced then comes to lie against the insulating layer 14, so that, in this refinement, there is no provision for an interspace 20 to occur between the insulating layer and the second concrete wall 12.
It is not necessary that the filling of the casting molds 17, 18 with concrete 22 (FIG. 1 a, 2 b, 3 b) or the filling of the free space 16 above the heap 15 with the insulating layer 14 (FIG. 1 e) must unavoidably take place after the insertion of the reinforcement body 13. Instead, the reinforcement body 13 may also be dipped into the mold already filled with concrete or with the insulating layer 14. The casting molds may be shakeable in order to achieve compaction of the concrete.
The invention is not restricted in its implementation to the preferred exemplary embodiment specified above. On the contrary, a number of variants are conceivable which make use of the illustrated solution even in versions which are of a fundamentally different kind. All the features and/or advantages, including structural details or spatial arrangements, which may be gathered from the claims, the description or the drawings may be essential to the invention both in themselves and in the most diverse possible combinations.

LIST OF REFERENCE SYMBOLS

10 Concrete element
11 First concrete wall
12 Second concrete wall
13 Reinforcement body
13′ Projecting portion of the reinforcement body
13″ Cast-in portion of the reinforcement body
14 Insulating layer
15 Heap
16 Vertical free space
17 Casting mold
18 Casting mold
19 Bottom
19 Interspace
20 Free space
21 Liquid concrete
23 Heaping container

Claims

1.-7. (canceled)

8. A method for producing a multi-layered reinforced concrete element (10), having at least one first concrete wall (11) in composite with a reinforcement body (13), the concrete element (10) comprising an insulating layer (14) bearing at least indirectly against the first concrete wall (11), and the reinforcement body (13) being designed to project at least partially out of the first concrete wall (11) and to penetrate the insulating layer (14), comprising the following steps:

provision of the composite of the first concrete wall (11) with the reinforcement body (13) projecting partially out of this,

provision of a heap (15), in particular in an upwardly open heaping container (23),

arrangement of the first concrete wall (11), together with the reinforcement body (13) arranged on it, above the surface of the heap (15), in such a way that a projecting portion (13′) of the reinforcement body (13) is arranged on the underside of the first concrete wall (11) and is dipped only partially into the heap (15), so that a vertical free space (16) remains between the surface of the heap (15) and the underside of the first concrete wall (11),

filling of the free space (16) with a reaction mixture, and

setting of the reaction mixture to form the insulating layer (14).

9. The method as claimed in claim 8, characterized by the preceding step of the casting and setting of the first concrete wall (11), wherein, by means of the casting, a portion (13″) of the reinforcement body (13) is cast into the first concrete wall (11) and a further portion (13′) of the reinforcement body (13) projects out of the first concrete wall (11).

10. The method as claimed in claim 8, characterized by the further method steps, provided after the formation of the insulating layer (14):

provision of a casting mold (18),

insertion of the composite of the first concrete wall (11), of the reinforcement body (13) projecting partially out of this and of the insulating layer (14) formed into the casting mold (18), in particular, already filled with liquid concrete, the projecting portion (13′) of the reinforcement body (13) and the insulating layer (14) formed being arranged underneath the first concrete wall (11),

filling of the casting mold (18) with liquid concrete (22) if this is not already prefilled with concrete,

setting of the second concrete wall (12), into which the projecting portion (13′) and the reinforcement body (13) is at least partially cast.

11. The method as claimed in claim 10, characterized in that, during the filling of the casting mold (18) with liquid concrete (22) and the generation of the second concrete wall (12), a free space (21) formed between a bottom (19) of the casting mold (18) and the underside of the insulating layer (14) is filled only partially with liquid concrete (22), so that a free interspace (20) is formed between the insulating layer (14) and the second concrete wall (12).

12. The method as claimed in claim 10, characterized in that, during the filling of the casting mold (18) with liquid concrete (22) and the generation of the second concrete wall (12), a free space (21), formed between a bottom (19) of the casting mold (18) and the underside of the insulating layer (14), in the casting mold (18) is filled completely with liquid concrete (22), so that the insulating layer (14) and the second concrete wall (12) are formed so as to bear at least indirectly one against the other.

13. The method as claimed in claim 8, characterized by the further method steps, provided after the formation of the insulating layer (14):

insertion of the composite of the first concrete wall (11), of the reinforcement body (13) projecting partially out of this and of the insulating layer (14) formed into the casting mold (18), the projecting portion (13′) and the insulating layer (14) being arranged above the first concrete wall (11),

filling of the casting mold (18) with liquid concrete (22), as a result of which, after setting, a second concrete wall (12) is formed, the projecting portion (13′) of the reinforcement body (13) being cast in at least partially and preferably completely with the concrete of the second concrete wall (12).

14. The method as claimed in claim 8, characterized in that, during the operations of filling the casting molds (18), the first concrete wall (11) and/or the insulating layer (14) are/is oriented essentially horizontally.