METHOD AND DEVICE FOR PRODUCING CONCRETE COMPONENTS

Abstract

In the process of the invention for producing concrete components, carbon fibers which have been prestressed by means of tensile stress or tensile-stressable fibers of at least one textile structure comprising carbon fibers are embedded in a concrete matrix. At least one textile structure comprising carbon fiber bundles is laid in a mold. The carbon fiber bundles are inserted, in each case at a distance from one another, into two accommodation elements which are arranged at two diametrical end faces of the mold and can be connected on the end walls of the mold or thereto through openings so that hollow spaces within the accommodation element are filled with a rapid-curing viscous composition having a mineral basis or a rapid-curing polymer. After curing of the composition or of the polymer, tensile forces act on one or both accommodation element(s) in the longitudinal direction of the carbon fiber bundles at at least one end face by means of a tensioning device. While the tensile forces are acting, the interior of the mold is subsequently filled completely with viscous concrete. After curing of the concrete, the tensile forces on the prestressed carbon fiber bundles are largely transferred to the cured concrete and the concrete component can then be removed from the mold.

Claims

1. A process for producing concrete components in which carbon fibers prestressed by means of tensile stress or tensile-stressable fibers of at least one textile structure made of carbon fibers are embedded in a concrete matrix, wherein at least one textile structure comprising carbon fiber bundles (8) is laid in a mold (4), where the carbon fiber bundles (8) are inserted, in each case at a distance from one another, into two accommodation elements (1) which are arranged at two diametric end faces of the mold (4) and are arranged, supported or connectable on/to the end walls of the mold (4) through openings (3) so that hollow spaces within the accommodation element (1) are filled with a rapid-curing viscous composition having a mineral basis or a rapid-curing polymer and, after curing of the composition or of the polymer, tensile forces act in the longitudinal direction of the carbon fiber bundles (8) by means of a tensioning device (7) on one or both accommodation element(s) (1) at at least one end face and while the tensile forces are acting the interior of the mold (4) is subsequently filled completely with viscous concrete, and after curing of the concrete, the tensile forces of the prestressed carbon fiber bundles are largely transferred to the cured concrete and the concrete component is then removed from the mold and compressive forces are exerted perpendicular to the tensioning direction at at least two diametrically opposite sides of the accommodation element (1) during the filling of the hollow spaces in the accommodation element (1) and until after curing of the composition or of the polymer.

2. The process as claimed in claim 1, characterized in that the compressive forces are increased further after curing.

3. The process as claimed in claim 1, characterized in that the carbon fiber bundles (8) are kept in position within the accommodation element (1) by means of spacers (5) and/or transverse clamping elements (6).

4. The process as claimed in claim 1, characterized in that a lay-up comprising carbon fibers is used.

5. The process as claimed in claim 1, characterized in that a plurality of accommodation elements (1) which are preferably connected to one another in a pivotable manner and at which tensile forces preferably act in different axial directions are arranged at at least one end face of the mold (4).

6. The process as claimed in claim 1, characterized in that the carbon fiber bundles (8) are inserted into an accommodation element (1) curved in at least one direction relative to a plane and fixed therein.

7. The process as claimed in claim 1, characterized in that particles, in particular mineral particles, are applied to the surface of carbon fibers within the accommodation elements (1) and fixed there.

8. An apparatus for carrying out the process as claimed in claim 1, characterized in that at least one textile structure comprising carbon fiber bundles (8) can be laid in a mold (4) and carbon fiber bundles (8) can be inserted through openings into two accommodation elements (1) arranged at opposite end faces and be positioned at a distance from one another and hollow spaces within the accommodation elements (1) can be filled with a rapid-curing composition having a mineral basis or a rapid-curing polymer and a device by means of which tensile forces are exerted on the carbon fiber bundles (8) is present at at least one of the accommodation elements (1) and a device (6) which exerts compressive forces on the side walls of the accommodation elements (1) is present on the accommodation elements (1) at each of at least two diametrically opposite sides.

9. (canceled)

10. The apparatus as claimed in claim 8, characterized in that spacers (5) for positioning and fixing of the carbon fiber bundles (8) are present within the accommodation elements (1) and/or a clamping coating which is preferably composed of an elastomeric material is present in/in the openings (3) through which carbon fiber bundles (8) are inserted into the accommodation elements (1).

11. The apparatus as claimed in claim 8, characterized in that the interior surface of the accommodation element (1) is rough or profiled.

Description

[0036] The figures show:

[0037] FIG. 1 an example of an apparatus according to the invention in plan view;

[0038] FIG. 2 a detail B from FIG. 1;

[0039] FIG. 3 the section A-A from FIG. 1;

[0040] FIG. 4 the section C-C from FIG. 1;

[0041] FIG. 5 an example of an apparatus in which tensile forces act in various axial directions;

[0042] FIG. 6 a plan view of a part of an accommodation element having a gripping tensioning device;

[0043] FIG. 7 a section D-D from FIG. 6;

[0044] FIG. 8 a side view of a part of an example of an apparatus according to the invention and

[0045] FIG. 9 the section E-E from FIG. 8.

[0046] FIG. 1 shows a plan view of part of an example of an apparatus according to the invention. In the depiction, an accommodation element 1 is arranged at an end face of a mold 4 and rests against this end face and/or closes-off/seals the mold 4. In an analogous way, a second accommodation element 1 is present at the opposite end face, but this is not shown here.

[0047] Openings 3 are present at the end face of the accommodation element 1 which is arranged at the end face of the mold 4 and the carbon fiber bundles 8 of a lay-up made up of carbon fibers are inserted through these openings into the interior of the accommodation element 1. Spacers 5 for the carbon fiber bundles 8 of the lay-up are additionally present in the accommodation element 1. At two opposite sides of the accommodation element 1 there are transverse clamps 6 by means of which compressive forces which act on the corresponding outer walls of the accommodation element 1 can be applied.

[0048] A clamping coating composed of an elastomer is in each case present in the openings 3. The clamping coatings seal the accommodation element 1 from the interior of the mold 4 and exert a clamping action on the carbon fiber bundles 8. A slight prestressing of the carbon fiber bundles 8 within the accommodation element 1 can be achieved by means of this clamping action when the accommodation element 1 is drawn to the left here by means of a screw drive or a pressure cylinder 7.

[0049] After attainment of a particular degree of prestressing of the carbon fiber bundles 8 within the accommodation element 1, the hollow spaces can be filled with polymer concrete as viscous composition having a mineral basis in a suitable viscous consistency. After about one hour, the polymer concrete has been sufficiently cured and has a strength by means of which secure material-to-material bonding between polymer concrete and carbon fiber bundles 8 can be achieved. The carbon fiber bundles 8 can now be tensioned by drawing back the pressure cylinder 7. The interior of the mold 4 through which the carbon fiber bundles 8 of the lay-up are conducted to and into the other accommodation element 1 (not shown) can be filled completely with concrete, so that virtually no voids are formed.

[0050] Before filling of the mold 4 with the concrete, the carbon fiber bundles 8 are subjected to tensile forces by actuation of the cylinder 7. Here, the yoke-shaped element 9 and a pin 10, which can also be a flange, which are connected to the accommodation element 1 are moved in the direction pointing away from the mold 4. The tensile forces acting on the carbon fiber bundles 8 at least in the interior of the mold 4 are then, for example, in the range from 50 kN to 100 kN at a fiber cross section of 50 mm.sup.2.

[0051] It can be sufficient for these prestressing forces to be applied only from one side and the compressive forces to act only at one accommodation element 1 while the other accommodation element 1 is kept fixed.

[0052] FIG. 2 shows a detail from FIG. 1 in enlarged form. The end face 2 of the accommodation element 1 closes off at the end face of the mold 4 in order to prevent concrete from flowing out of the mold at a later time. The openings 3, in which a clamping coating is present in each case, through which the carbon fiber bundles 8 are conducted through the mold 4 and from there into the interior of the accommodation element 1 are present in this end face 2. A clamping coating can, for example, consist of polyurethane. The internal diameter of the openings 3 is, in combination with the thickness of the clamping coating, made such that a free cross section which is smaller than the outer cross-sectional dimensions of the carbon fiber bundles 8 is obtained.

[0053] The section A-A from FIG. 1, as shown in FIG. 3, makes it clear that spacers 5 for the carbon fiber bundles 8 of the carbon fiber lay-up, as an example of a textile structure, can be present in the interior of the accommodation element 1.

[0054] The section C-C shown in FIG. 4 again clarifies the arrangement of transverse clamping elements 6 on the side walls of the accommodation element 1. Instead of the transverse clamping element 6, it is also possible to use pressure punches which exert force on the opposite sides of the accommodation element 1.

[0055] FIG. 5 is intended to show that even relatively geometrically complex concrete components can be produced by means of the invention. Here, a plurality of lay-ups made of carbon fibers are present in a mold. The carbon fiber bundles 8 of these are oriented in different axial directions, so that they are prestressed by the tensile forces applied corresponding to this respective axial direction. At a yoke-shaped element 9 which is appropriately bent or kinked, the tensile forces can act in the axial direction assigned to the respective force application position corresponding to the orientation of the carbon fiber bundles 8 at various positions by means of a screw drive or a cylinder 7 when the polymer concrete has cured sufficiently in the accommodation element 1.

[0056] However, it is also possible to connect a plurality of yoke-shaped elements 9 to one another in a pivoting manner. Here, the linkages can be formed with the aid of the pin 10. The orientation of the individual yoke-shaped elements 9 then depends on the respective tensile force direction acting on a yoke-shaped element 9.

[0057] FIG. 6 shows a plan view of part of an apparatus of the example shown in FIG. 5.

[0058] FIG. 7 corresponds to the section D-D of FIG. 6.

[0059] FIG. 8 shows a cut side view of an apparatus. It can be seen from the section E-E shown in FIG. 9 that a mold 4 which has one or more curves and optionally correspondingly curved accommodation element(s) 1 can be used and it is in this way possible to produce a wavy or otherwise curved concrete component in which the carbon fiber bundles 8 are embedded in prestressed form in the concrete. Here, a plurality of transverse clamps 6 are arranged along the mold 4 and the accommodation elements 1 so that compressive forces can be exerted from two opposite sides.