FI66138C - CONTAINER MASKINELL BETONGGJUTNING DAER MAN MED HJAELP AV EN ENGAONGSMATRISREMSA AOSTADKOMMER MOENSTRING AV BETONGENS YTA - Google Patents

Description

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Use of a disposable matrix strip in the continuous casting of concrete blanks, in particular for shaping the outer surfaces of concrete screed elements

The invention relates to the use of a disposable matrix strip with a casting carriage with a negative pattern of the desired pattern, not more than the width of the casting platform and at least the length of the casting platform, discharged from the moving roll under concrete, in particular for shaping the outer surfaces of concrete wall elements.

It is already known to cast concrete wall and other elements into a mold so that the molded concrete forms shapes depressed by the mold surface, so that the surface of the concrete element against the mold can be shaped by making protrusions or recesses in the mold surface. The shaped surface can also be cast with a smooth surface mold by placing a plate or mat on the bottom of the mold that is smooth on one surface and shaped on the other surface to provide the desired concrete surface shapes. Usually, such a mat is a material that can be molded or otherwise shaped, such as reinforced plastic or rubber-based mass. In addition, it is usually used several times.

Another way to shape a concrete surface is the so-called washed concrete technique. It applies a retarder to the surface of the mold, which acts in such a way that the cement in the thin surface layer of the element to be cast against the mold does not harden during the lifting of the element from the mold. In this case, the uncured cement can be washed away and the aggregate granules in the concrete are exposed. By varying the size and color of the concrete aggregate granules, the desired appearance is then obtained on the concrete surface after washing. It is also known to use paper in which the retardant is impregnated instead of a liquid retardant in the production of small concrete pieces, for example yard tiles. In this case, the possibility of errors in connection with the application of the retardant (retarder is not everywhere), odor nuisances (retarders contain solvents dangerous to health) and the work of cleaning the mold are used, because when using a liquid retarder some

The new method of manufacturing wall elements, known from patent application 783461, differs from conventional mold production in that instead of a conventional mold it has a mold base 100-120 meters long, on which the elements are cast in one piece and cut into elements of the desired length after curing. The use of the above-mentioned concrete surface shaping means in connection with this manufacturing method entails a number of disadvantages, the most important of which are the following: A) In the case of washed concrete surfaces, a liquid retarder causes problems in the formwork substrate method. This is very slow and there is a high chance that the same amount of retardant will not come to each substrate, which in turn will result in an uneven surface in the end result. In addition, the resulting health hazards are greater than normal because the volatile solvent is present on a larger surface at the same time. An additional difficulty is that the retarder requires a certain waiting time before casting begins, which slows down the entire manufacturing process. After dismantling the molds, part of the cement layer remains on the casting substrate, which considerably increases the need to clean the casting substrate and slows down the process.

B) When using formwork mats, an entire mat the length of the mold base is required instead of a mold-length plate. Depending on the carpet material, this may be downright impossible or at least a difficult and expensive way to shape a concrete surface. In addition, when a long mold base is used, I0.Q4.84 3 661 38 the various thermal movements between the molding mat and the molding base and the possible unforming elongation caused by the load (casting pressure) become detrimental. Because of the high cost of the molding mat, it must be used several dozen times to achieve an economical result, the number of economic elements to be cast on the same molding mat becomes unreasonably large, up to ten times that of conventional mold making.

The object of the present invention is to eliminate or substantially reduce the above-mentioned disadvantages in the production of concrete elements by the casting substrate method. The invention is based on the use of a matrix strip as defined above, such that the matrix strip is used in the mechanical and continuous casting of concrete blanks so that the pattern is transferred from the matrix strip on the casting surface to the adjacent surface of the cast concrete blank.

The sheet or film acting as a matrix strip is applied to the formwork substrate immediately before the concrete is poured, thus eliminating the previously used preparation time. A further essential feature of the method is that the sheet or film material used is so inexpensive that it allows for single use, making the method flexible. The most preferred method is when the film material to be used is located on a roller placed in a rack at the front of the concrete casting machine to be used, from which the film material is fed to the casting substrate just before the concrete mass is applied and compacted.

A technique similar to the use of a disposable matrix strip is disclosed in the following publications: U.S. Pat. No. 3,683,760 discloses a strip which serves as a water distribution channel. According to the publication, concrete objects are poured in such a way that dry concrete is driven from 10.04.84 4 66138 vehicles moving along rails to a casting platform with said strip. After casting, water is fed through the strip to the concrete, where the water rises to the concrete due to the capillary action and wets this and thus causes the concrete to harden.

DD 1202 discloses a method for overlapping structural elements by applying a foil over a finished element, on which a new structural element is cast.

DE-OS 19 28 875 describes a method for cutting and mixing paper impregnated with a retarder in a rotary casting table system.

DE-AS 12 11 098 discloses a method in which a paper film is used between the surface of a cast concrete element and a mold, the elongation of which due to moisture in the concrete is greater in one direction than in the other, leaving the paper wrinkled and leaving small patterns in the cast concrete body.

DE-OS 28 20 576 discloses a method for providing a washed concrete surface using a mold with surfaces of different heights. These surfaces can be treated with a retarder and / or toner.

DE-OS 25 25 011 discloses a matrix in which the surface patterns are formed in such a way that the matrix is formed by two films attached to each other, the air-filled spaces between which provide corresponding recesses in the concrete object to be cast.

The invention will now be explained in light of the following examples: Preparation of a washed concrete surface In this case, a paper impregnated with a retardant is used as the film. The paper is on a roll having a width equal to the width and length of the concrete surface to be washed, or most preferably a multiple thereof. Roll of paper

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s 66138 is placed in a rack at the front of the casting machine with respect to the direction of travel. With the casting machine at the end of the casting tray, retarder paper is pulled from the roll for a distance of about the length of the casting machine and the edge of the paper is attached to the end of the casting tray. The paper is tightened on the casting substrate, e.g. by means of a spring in the roll and a possible spring-loaded roll under the roll in the plane of the surface of the casting substrate. Of course, other known methods for tightening paper can be used. Once the casting begins, the paper impregnated with the retarder is released from the roll at the rate of the advancing speed of the casting machine.

When the casting tray is completely cast, the paper is cut off and the casting machine is moved away. When the string of elements has hardened sufficiently, it is sawn into elements of the desired length, which are lifted one by one from the casting base. The paper is removed before washing and recycled into a waste container, for example, so the casting tray is ready for new use immediately after the elements have been dismantled. After removing the paper, the concrete surface is washed normally.

Preparation of a shaped concrete surface In this example, a multilayer structure is used as the film, for example a two-layer film, one of which is smooth and the other shaped, for example corrugated, and the films are glued together so that air spaces remain between the films. In practice, the film may be, for example, corrugated cardboard, in which the corrugated part is made of a material which does not adhere to concrete, for example silicone-treated paper. The film is used in the same manner as in the previous example. In addition to the corrugated pattern, several other patterns can be considered, which can be achieved, for example, by passing corrugated cardboard over a shaped roll, whereby the depressions made by the roll in the cardboard are visible as protrusions on the concrete surface.

Of course, other uses based on the same inventive idea can be considered.

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Advantages of the invention

Compared to the methods currently in use, the invention offers the following obvious advantages: - occupational safety problems associated with the use of a liquid retarder are eliminated - the manufacturing process is considerably speeded up - , and the cumbersome handling and storage of rigid and heavy shaping mats is eliminated from the work steps.