ES2973045T3 - Procedure and installation to manufacture concrete slabs - Google Patents

Abstract

The object of the invention is a method of manufacturing prefabricated slabs by pouring concrete or similar on a platform (1), characterized in that it comprises at least one stage before pouring the concrete, during which a matrix (2) profiled following a relief (a, b, c, d, e) and completely covering the platform, so that once the concrete has set and the slab is unmolded, said relief is printed on the underside of the slab. said matrix. The invention also relates to the prefabricated concrete slabs thus obtained, as well as a facility to implement the process. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Procedure and installation to manufacture concrete slabs

The invention relates to a procedure and an installation for the manufacture of prestressed concrete slabs. Prefabricated prestressed concrete floor slabs, hollow core or solid, are generally manufactured on manufacturing benches traditionally composed of a flat metal platform 10 to 12 mm thick and 1.20 to 2.40 m wide, with one side flat and uniform bottom.

These manufacturing benches generally extend over 100 to 200 m in length.

In certain architectural applications, the lower part of these slabs constitutes a ceiling for which no subsequent finish such as false ceiling, formwork or cladding is foreseen.

For this reason, the flat bottom part of these slabs, which only receives a glaze or paint to give it color and which must present an architecture with moldings, was until now technically difficult to manufacture and very expensive.

To obtain such a result, until now it was necessary to design and manufacture a base platform with high mechanical resistance. For this, a 10 to 12 mm sheet was used and architectural elements fixed by welding or mechanical intermediate elements were added.

This arrangement had several drawbacks, such as being very expensive, permanently fixing the architectural finish of the base platform and offering a low quality finish due to the images left by the welding and fixings.

To modify the architecture, it was necessary, in fact, to completely remake the base platform of 10 to 12 mm sheet metal and weld or fix new architectural profiles to it, hiding the welds and profile joints as much as possible, to avoid burrs.

Thus, the patent document US 3 938 922 A describes, for example, a slab prefabricated by pouring concrete, obtained according to a manufacturing procedure that includes at least one stage before pouring the concrete, during which it is placed on the base platform a matrix profiled according to a relief visible in figure 2 of the patent document US 3938922 and that completely covers the base platform, so that once the concrete has set and the slab is unmolded, said relief is printed on the underside of the slab of said matrix. However, the matrix cannot be a single-piece sheet because the retention of the prestressing cables induces the displacement of the constituent elements of the matrix that are generated by its reasons when the concrete contracts. On the contrary, the matrix is expected to be made up of several elements with spaces between each of them, these spaces being reduced when the concrete is prestressed.

These financial and technical limitations have meant that until now no prestressed architectural slab was economically viable.

Patent document JP S59 21764 B2 describes a procedure for manufacturing prestressed slabs, prefabricated by pouring concrete or the like on a platform extending over a length of 100 to 200 m, comprising at least:

- a stage prior to the pouring of concrete, during which the active reinforcements are stretched along the entire length of the platform to form prestressed slabs,

- a stage of pouring the concrete by spreading and vibration or by means of a dosing-extruder. This document also discloses a facility for preparing prestressed and prefabricated concrete slabs or the like by pouring according to the preamble of claim 5.

The objective of the invention is to totally or partially overcome the aforementioned drawbacks by profiling a one-piece matrix, preferably made of thin sheet metal, according to the architect's wishes and placing it on the flat platform that guarantees mechanical resistance during the pouring of the concrete.

This matrix can integrate, thanks to its high-quality relief, also called profile, a large number of architectural elements such as slots, gaps, rounded elements and elements not at right angles, which are defined by the architect.

More precisely, the object of the present invention is a process for manufacturing precast prestressed slabs by pouring concrete or the like on a platform according to claim 1.

Optional, complementary or substitute features of the invention are set out below.

The matrix profiled according to a predefined relief can be formed by a single piece of sheet metal, without welding or joints, for long lengths of up to 200 m.

The matrix profiled according to a predefined relief can be a thin steel sheet.

The procedure may include at least one step before concrete pouring during which passive reinforcing structures are placed on the platform covered with the matrix to manufacture solid or honeycomb elements. The concrete pouring stage can be followed by:

- a drying stage, which consists of heating the poured concrete to a temperature between 35 and 60°C, - a relaxation stage of the active reinforcements,

- a stage of demolding and then storage of the slabs.

Reference is also made to a prestressed and prefabricated slab by pouring concrete not claimed and obtained according to a manufacturing process according to an embodiment of the invention, so that the slab extends over a length of 100 to 200 m and has a surface state free of joints and burrs.

By “surface condition free of joints and burrs” is understood the fact that the slab has a surface condition corresponding to that of concrete poured on a surface devoid of roughness visible to the naked eye. In other words, the surface state of the slab according to the invention is free of burrs resulting from the welds and joints of profiles present in the state of the art.

The object of the invention is also an installation for molding prestressed and prefabricated concrete slabs or similar according to claim 5.

The matrix profiled according to a predefined relief is formed by a single-piece sheet.

The matrix profiled according to a predefined relief can be a thin steel sheet.

The matrix profiled according to a predefined relief is a thin sheet, preferably with a thickness between 0.5 and 1 mm.

Other advantages and particularities of the invention will appear upon reading the detailed description of embodiments and embodiments, which are not limiting, and the following attached drawings:

- Figure 1 is a section view of examples of architectural profiles of slabs obtained by the procedure according to the invention.

- Figure 2 is a perspective view of a slab manufacturing bench according to the invention.

- Figure 3 is a section view of a slab manufacturing bench according to the invention.

For the purposes of clarity and conciseness, references in the figures correspond to the same elements.

The present invention consists of profiling a matrix of thin sheet metal, according to the architect's wishes, and placing it on the flat platform which, in turn, ensures mechanical resistance.

This very fine matrix can integrate, thanks to its profiling, precise architectural elements such as slots, gaps, rounded elements, elements not at right angles, ribs.

These profiles or reliefs extend longitudinally and are concave and/or convex.

Figure 1 illustrates a certain number of profiles or reliefs a, b, c, d, e that can be obtained.

These profiles or reliefs are mainly formed by grooves and ribs that extend longitudinally. These profiles are illustrated for informational purposes only and are in no way limiting. They can be modified and declined in different variants according to the architect's wishes.

By having a complete set of dies, it is possible to easily change the profile of the slabs and offer tailor-made production.

With reference to Figure 2 and Figure 3, a manufacturing bench of an installation for molding prefabricated prestressed concrete slabs or the like according to the invention is shown.

The bench particularly comprises a platform 1 made of sheet metal whose thickness is preferably between 10 and 12 mm.

The installation is completed with a dosing machine capable of pouring concrete and with heating means to harden it, elements not represented in the figures.

The bottom of the platform is covered with a matrix 2 profiled according to a relief such as a, b, c, d, e, capable of completely covering the platform on which the concrete is poured.

According to the invention, the matrix 2 is composed of a single piece sheet. Therefore, the array is made in a single length, more precisely that of the bench, which extends between 100 and 200 m.

The fact that there are no splice joints or longitudinal joints guarantees a perfect finish on the lower part of the slab.

This platform-supported array can be used for about a hundred cycles.

To ensure sufficient mechanical strength even if the stresses are mainly absorbed by the platform during the manufacturing of the slabs, the matrix 2 is a thin sheet, for example, made of steel.

To minimize its weight, the matrix is a thin sheet, preferably with a thickness between 0.5 and 1 mm. To reinforce the matrix, the present invention proposes housing in the concave part of the profiles or reliefs supports that are thus interposed between the monobloc matrix and the platform.

This prevents the concrete from deforming the profiles or reliefs under its weight during pouring.

Figure 3 clarifies an exemplary embodiment in which steel cables 4 extend within the longitudinal slots.

Next, the manufacturing process of precast prestressed slabs by pouring concrete or similar will be explained.

According to the invention, the procedure comprises at least one stage before pouring the concrete, during which a matrix 2 profiled according to a relief, which completely covers the platform, is placed on the platform 1. The concrete is poured preferably using a batching machine with mobile cores to form a prestressed hollow core slab or without a core to form a solid slab.

Thus, the manufactured slabs can be solid or honeycomb. Honeycomb slabs are generally manufactured using a dosing machine or an extruder that incorporates metal cores the size of each alveolus. These nuclei have reciprocating movements. The concrete descends onto these cores and, through their swaying movements, ensures its distribution. The concrete is also subjected to vibrations and then compressed enough so that it is very compact and remains stable after leaving the batcher.

Once the cores are removed, alveoli the size of the cores remain in the concrete.

As regards the procedure, 2 steel prestressing cables 3 are laid on the platform 1 covered with the matrix, which constitute wire-shaped reinforcing structures, these cables also being called strands or braided wires.

These wire-shaped reinforcements protrude in the longitudinal direction of the slab to allow the anchoring of the floor in the wall braces. Of course, any other type of reinforcement may be suitable.

These active reinforcements, called strands, are tensioned according to the characteristics of the steel and then relaxed to prestress the concrete.

Once the matrix and accessory reinforcements have been placed, we proceed to the concrete pouring stage by spreading and vibration or by using a dosing machine that moves on the manufacturing track at a speed of 2.5 m/minute.

The concrete pouring stage is followed by a tempering or curing stage, which consists of heating the poured concrete to a temperature between 35 and 60°C.

The strip of cured and still fresh concrete, which is the size of the deck, is then cut to the desired length for each slab.

When the concrete has sufficient resistance, prestressing is carried out by cutting the strands to separate each slab from each other.

During prestressing, the slab contracts as do the grooves and ribs of the relief modeled by matrix 2. In this way, the assembly slides on matrix 2 without affecting the surface state of the slab. Each floor slab is then unmolded with its structured lower part that presents a surface state free of joints and burrs.

The matrix placed on the platform can be used for about one hundred cycles and replaced at will by a new profile that responds to a new requirement of the architect.

Delivery to site and installation are the same as for an ordinary slab.

The present invention provides architects with the ability to design and customize the underside of concrete load-bearing floors at a low additional cost using the existing facilities of factories producing solid or hollow core prestressed slabs.

The manufacturing procedure described is easily industrializable. It allows the manufacturing of prestressed concrete architectural slabs, for construction, with adapted, controlled and reproducible technical characteristics. The slabs thus obtained offer an optimized architectural finish as they are free of joints and burrs, for a controlled production cost.

From this description it is clear that the invention makes it possible to achieve the set objectives. The present invention is not limited to the described embodiments, but extends to any modifications and variations obvious to a person skilled in the art while remaining within the scope of the protection defined in the appended claims.

Furthermore, the different characteristics, forms, variants and embodiments of the invention can be associated with each other in various combinations as long as they are not incompatible or mutually exclusive.

Claims (5)

1. A procedure for manufacturing prestressed slabs, prefabricated by pouring concrete or similar on a platform (1) that extends over 100 to 200 m, comprising at least: - a stage prior to pouring the concrete, during which a monobloc matrix (2) is placed on the platform (1), both the platform and the matrix extending over a length of 100 to 200 m, the matrix being made of thin sheet metal, preferably between 0.5 and 1 mm thick, profiled according to a relief (a, b, c, d, e) and that completely covers the platform, so that once the concrete has set and the slab has been unmolded , the lower face of the slab is printed with the relief of said matrix, and - a stage prior to the pouring of the concrete, during which active reinforcements (3) are laid along the entire length of the platform (1) covered by the matrix (2) to form prestressed slabs, - a stage prior to the pouring of the concrete, during which supports (4) are placed in the concave part of the reliefs between the monoblock matrix and the platform, to prevent the concrete from deforming the reliefs under its weight during pouring, - a stage of pouring the concrete by spreading and vibration or using a sliding formwork dispenser or extruder. 2. The method according to claim 1, characterized in that the matrix (2) profiled according to a relief (a, b, c, d, e) is a thin steel sheet. 3. The procedure according to any of the preceding claims, characterized in that it comprises at least one stage prior to pouring the concrete, during which solid or hollow elements are placed on the platform (1) covered with the matrix (2) to form slabs. alveolar. 4. The procedure according to any of the preceding claims, characterized in that the concrete pouring stage is followed by: - a tempering or curing stage, which consists of heating the poured concrete to a temperature between 35 and 60°C, - a cutting stage of the still fresh tempered concrete that has the dimensions of the platform, according to the desired length for each slab, - a stage in which active reinforcements or reinforcements are relaxed (3), - a stage of demolding and storage of the slabs. 5. An installation for molding prestressed and prefabricated concrete slabs or similar, the installation comprising in particular a platform (1), a sliding formwork extruder or means for pouring the concrete by spreading and vibration, heating means and, advantageously , active armor. characterized in that it further comprises a one-piece matrix (2), both the platform and the matrix extending over a length of 100 to 200 m, the matrix consisting of a thin metal sheet, preferably with a thickness of between 0.5 and 1 mm, and profiled according to a relief (a, b, c, d, e) capable of completely covering the platform, supports (4) housed in the concave part of the reliefs, between the monobloc matrix and the platform, to avoid that the concrete deforms the reliefs under its weight during pouring.