JP2010005805A - Precast type concrete block and its method of manufacturing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precast type concrete block restrained in the generation of recesses in the surface due to air bubbles, and provide its method of manufacturing. <P>SOLUTION: On the molding surface that makes at least the undersurface, of the forms of an outside form, core form and the like, there is arranged a permeable sheet whereinto a ready-mixed concrete can penetrate, such as a non-woven fabric, paper, woven cloth and knitted cloth, and the ready-mixed concrete is poured into the forms and demolded after it has hardened. By the above, on at least part of the molding surface of the concrete block or in the vicinity under its surface there is embedded the permeable sheet 30 consisting of the non-woven fabric, paper, woven cloth, knitted cloth or the like that permits the ready-mixed concrete to penetrate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention mainly relates to precast concrete blocks such as variable side groove blocks and box culverts, and a method for manufacturing the same. In particular, the present invention relates to a concrete block in which bubbles generated on the surface of the concrete block are reduced or a method for producing the concrete block.

  In a precast type concrete block such as a variable side groove block, a box culvert or the like, a type of concrete block that is molded using a core mold, as shown in FIG. Many recesses made of bubbles are formed. This occurs because when the ready-mixed concrete is put into the mold, the air trapped in the concrete rises and hardens while remaining as bubbles on the molding surface on the lower side of the core mold. To do. Since the smoothness is greatly impaired by the concave portions generated by the bubbles, conventionally, the concave portions are filled with mortar to be repaired or shaved and post-smoothing is performed.

  On the other hand, several methods for preventing the occurrence of recesses due to bubbles have been proposed. For example, there is a method of removing bubbles by putting ready-mixed concrete into a mold 1 having an outer mold 2 and a middle mold 3 according to the following procedure. First, the mold 1 is tilted, and the lower molding surface 3b of the middle mold 3 is tilted. And the ready concrete is thrown in from the left side space part 1a in the mold 1 which is relatively lowered, and at least the bottom space part 1c in the mold 1 is filled with the ready concrete 10. At this time, the air in the bottom space 1c is sequentially pushed out to the ready-mixed concrete 10 rising obliquely along the lower molding surface 3b of the middle mold 3 so that the right space in the mold 1 Exit from 1b. Next, the direction of the mold 1 is set to the direction during curing. Then, ready-mixed concrete is put into the mold 1 to a predetermined position. By adopting such a configuration, the raw concrete is completely charged without air being confined in the bottom space portion 1c, and the concrete block 10 having no bubble recess is produced (Patent Document 1).

  Also, in a manufacturing method in which ready-mixed concrete is poured into a formwork to form a concrete block, a mixed liquid of a release agent and a mortar adhesive is applied to the inner surface of the formwork, and after drying, the transfer concrete is applied and solidified. After that, a method of manufacturing a concrete block has been proposed in which the mold is assembled, the ready-mixed concrete is poured into the mold, and then demolded after curing (Patent Document 2). According to the method for producing a concrete block, since the concrete block surface is formed as a transfer concrete layer by applying concrete to the inner surface of the mold and forming the transfer concrete layer in advance, the concrete block surface is not formed with a recess. This is effective in terms of a smooth surface.

  However, in the invention described in Patent Document 1, since the entire mold must be tilted, a dedicated facility must be prepared, which increases the cost for capital investment. Further, since the ready-mixed concrete cannot be put into the entire block until the air is exhausted, the ready-mixed concrete has to be put in twice and there is a problem that the manufacturing process increases.

  Further, in the invention described in Patent Document 2, a solution in which a mold release agent and a mortar adhesive are separately mixed is applied to the mold, and after drying, the transfer concrete must be applied and solidified. Therefore, it is necessary to wait for the solution to dry. Also, the coating process is a complicated operation and takes a very long time. Therefore, there is a problem that it takes too much time to produce a concrete block.

JP-A-10-180727 JP 2004-351813 A

  The present invention has been devised in view of the above problems, and is not limited to, but is made using a core mold such as a variable side groove block or a box culvert, and is a precast concrete block surface. An object of the present invention is to provide a precast-type concrete block in which the generation of recesses due to air bubbles is suppressed and a method for producing the same.

  In order to solve the problems as described above, the measures taken by the present invention are as follows.

  In the precast concrete block according to claim 1 of the present invention, a permeation sheet made of nonwoven fabric, paper, woven fabric, knitted fabric or the like capable of permeating concrete is formed on at least a part of the concrete block molding surface or in the vicinity below the surface. The gist is that it is buried.

  By adopting such a configuration, the permeation sheet can be embedded on the surface of the concrete block or in the vicinity of the surface, and the occurrence of recesses due to air bubbles on the concrete surface can be greatly reduced. In addition, if the permeation sheet is arranged at the very end of the concrete surface, a part of the surface of the permeation sheet can be exposed on the concrete surface, and the permeation sheet can be visually recognized as a surface pattern, and a concave portion due to some bubbles is generated. But it can be inconspicuous.

  In the precast concrete block according to claim 2 of the present invention, the permeation sheet is embedded in the surface of the concrete block formed by placing the formwork on the upper surface during the production of the concrete block. The gist of this is.

  By adopting such a configuration, it is possible to embed the permeation sheet on the concrete surface formed by the lower surface of the mold or the core mold at the time of production. Accordingly, it is possible to embed the permeation sheet by concentrating on the part where bubbles are likely to be generated, and it is possible to remove most of the recesses of the bubbles generated on the concrete surface.

The method for producing a precast concrete block according to claim 3 of the present invention is a non-woven fabric, paper, woven fabric, in which ready-mixed concrete can permeate the molding surface that forms at least the lower surface of the molds such as the outer mold and the core mold. By placing a permeation sheet such as a knitted fabric, pouring the ready-mixed concrete into the mold, and demolding after curing,
Producing a precast concrete block in which a permeation sheet made of non-woven fabric, paper, woven fabric, knitted fabric, etc., through which ready-mixed concrete can permeate, is embedded in at least a part of the molding surface of the concrete block or in the vicinity below the surface. Is the gist.

  By adopting such a configuration, a concrete block having a permeation sheet disposed on the surface or in the vicinity of the surface can be produced.

  The effects obtained by adopting the above means are as follows.

  According to the precast concrete block according to the present invention, a permeation sheet made of non-woven fabric, paper, woven fabric, knitted fabric, etc., through which ready-mixed concrete can permeate, is disposed on the surface of at least a part of the concrete block and in the vicinity below the surface. Therefore, the recessed part by the bubble which generate | occur | produces on the surface which has arrange | positioned the osmosis | permeation sheet can be reduced. Therefore, a concrete block having a surface with excellent aesthetics can be obtained, and work such as refilling a concave portion due to air bubbles with mortar or reshaping the surface, which has been conventionally performed, becomes unnecessary.

  The best mode for carrying out the “precast concrete block and method for producing the same” of the present invention will be described.

  The precast-type concrete block according to the present invention is obtained by embedding a permeation sheet such as non-woven fabric, paper, woven fabric, knitted fabric or the like which can permeate ready-mixed concrete in at least a part of the surface of the concrete block. . The vicinity of the surface refers to a position from a concrete surface where the permeation sheet can be visually recognized to a depth of about 5 mm, which is a depth at which the surface cannot be visually recognized at all from the position of the surface 0 mm. Preferably, it is embedded at a depth of 0 mm to 1 mm. More preferably, it is desirable that the entire permeation sheet is embedded at an even depth in an extremely shallow range of 0 mm to 0.3 mm or less. Visually, it is preferable that a part of the surface of the permeation sheet is slightly visible from the entire surface.

  The permeation sheet is not particularly limited as long as it has a permeability that allows the ready-mixed concrete to permeate from the back side to the front side when the ready-mixed concrete is poured in a state where it is placed on the concrete surface. Absent. Preferably, non-woven fabric, paper, woven fabric, knitted fabric, etc., through which ready-mixed concrete uniformly permeates are used. As a material, it is preferable to use a non-woven fabric made of synthetic fibers which are difficult to corrode. More preferably, a nonwoven fabric of polypropylene or polyethylene is used.

  The surface on which the permeation sheet is embedded is not limited, and a surface that is desired to suppress the generation of a concave portion due to bubbles may be appropriately selected. In particular, the surface of the concrete block may be embedded in the surface on which the mold is disposed on the upper surface when the concrete block is manufactured. Since this surface has the most tendency for air bubbles to stay, the concave portions due to most of the air bubbles are generated by this surface. Therefore, by embedding the permeation sheet on the surface, it is possible to efficiently prevent the occurrence of recesses due to bubbles with a small number of sheets.

  The precast type concrete block mentioned above is produced as follows. First, an osmosis sheet is installed in a place corresponding to the surface on which the osmosis sheet is to be embedded, in a mold or core. This installation method may be attached with a mechanism that allows the permeation sheet to be attached to the mold itself (see FIG. 2), or simply attached to the mold with tape or the like (see FIG. 6). . In addition, it is not always necessary to install it so as to stick to the surface of the formwork. This is because even if the permeation sheet floats slightly from the formwork, if the ready-mixed concrete is poured, it will naturally come close to the surface due to the pressure of the concrete. However, it goes without saying that when it is desired to embed uniformly at a position very close to the surface, it is preferable to attach it so as to adhere to the surface of the mold.

  The place where the permeable sheet is disposed is not particularly limited as described above. It is efficient if it is placed on a surface where the bubbles in the concrete move upward during curing, such as the lower molding surface of the core mold, and bubbles are likely to be generated. At this time, a plurality of air vent holes may be formed on the core-shaped surface.

  Then, by pouring the ready-mixed concrete into the mold, the ready-mixed concrete penetrates into the infiltrated sheet, and the concrete is cured in a state where the infiltrated sheet is embedded on the concrete surface or near the surface. And after hardening, it demolds and the precast type concrete block of the present invention is completed.

  The precast concrete block in which the permeation sheet thus created is embedded can greatly reduce the occurrence of bubble recesses on the surface. Moreover, even if the recessed part by a bubble generate | occur | produces, it can be set as a small recessed part compared with the recessed part of the bubble produced | generated in the state which has not embed | buried the permeable sheet.

  Hereinafter, the optimal example of the precast type concrete block 100 and its manufacturing method is described along FIGS. In addition, the Example and drawing demonstrated below illustrate the optimal form of the Example of this invention, and is not used for the objective limited to these structures.

  The first embodiment will be described in detail based on a precast concrete block called a so-called variable side groove block. The precast concrete block 100 according to the first embodiment includes two side wall portions 10 and 10, an upper surface plate portion 20, and a permeation sheet 30 embedded in the vicinity of the surface of the inner wall surface 21 of the upper surface plate portion 20. . The variable side groove block shown in the figure is drawn upside down from the state of the variable side groove block actually constructed.

  In Example 1, the osmotic sheet 30 is a non-woven fabric made of polypropylene fibers having a thickness of 0.15 mm and allowing ready-mixed concrete to permeate. In this nonwoven fabric, the entire permeation sheet is embedded at an even depth in an extremely shallow range of 0 mm to 0.3 mm or less, so that a part of the surface of the permeation sheet can be seen slightly from the surface of the inner wall surface 21. Has been.

  The variable side-groove concrete block 100 as described above is manufactured as follows. As shown in FIG. 2, the mold 50 for producing the precast concrete block 100 includes an outer mold 51 and a core mold 52. The outer mold 51 includes a bottom plate 51b, side plates 51a and 51a that are attached to both sides of the bottom plate 51b in a freely retractable manner, and a tread plate that is also attached to the front and rear in a manner that is also retractable (not shown). ) The core mold 52 includes a core mold bottom plate 52b and core mold side plates 52a and 52a that are detachably attached to the core mold bottom plate 52b. The core bottom plate 52b has a plurality of air vent holes (not shown). The core-type bottom plate 52b and the core-type side plates 52a, 52a are formed so as to be able to sandwich the permeation sheet 30 made of the above-mentioned nonwoven fabric made of polypropylene, and the entire surface of the core-type bottom plate 52b. Can be attached so as to be covered with the permeation sheet 30.

  As shown in FIG. 2, ready-mixed concrete is poured into the space between the outer mold 51 and the core mold 52 of the mold 50 configured as described above. Then, the mold 50 is cured while being filled with ready-mixed concrete (FIG. 3). In this state, the ready-mixed concrete permeates into the permeation sheet and is buried at a very shallow depth near the block surface. Thereafter, as shown in FIG. 4, the side plates 51 a and 51 a are tilted, and the permeation sheet 30 made of a nonwoven fabric attached to the bottom plate 52 b of the core mold 52 is removed from the core mold 52 while being removed. Take out the concrete block 100. Then, the penetration sheet 30a (refer FIG. 5) which is not embed | buried in the concrete block 100 is cut off with a cutter etc., and the precast-type concrete block 100 is completed.

  The precast concrete block 100 manufactured in this way can be a concrete block in which the concave portions of bubbles on the surface are greatly reduced. Therefore, it is not necessary to perform surface treatment in a later process, and the product can be shipped immediately.

  In addition, this invention is not limited to embodiment mentioned above. For example, the method of disposing the permeation sheet is not particularly limited to the present embodiment. For example, as shown in FIG. 6, a conventional core mold is used and a tape is applied to the core mold surface. For example, the permeation sheet may be attached and disposed. Such an installation method has the advantage that it is not necessary to cut out the permeation sheet 30 with a cutter or the like because all the permeation sheets are embedded in the precast concrete block. Further, in the present embodiment, the permeation sheet is provided only on the inner wall surface 21 of the upper surface plate portion 20 where the concave portions due to bubbles are most likely to occur, but it is not excluded to embed the permeation sheet 30 in other parts. Absent.

  Further, a concrete block other than the concrete block for the variable side groove, such as a box culvert or another block, may be used.

1 is a perspective view of a precast concrete block 100 according to Embodiment 1. FIG. It is a side view which is a part of process of producing the precast-type concrete block 100 which concerns on Example 1, and shows the state which pours ready-mixed concrete. It is a side view which is a part of process of producing the precast type concrete block 100 which concerns on Example 1, and shows the state under curing. It is a side view which is a part of process of producing the precast-type concrete block 100 which concerns on Example 1, and shows the state of a demolding. 1 is a cross-sectional view of a precast concrete block 100 according to Example 1. FIG. It is a side view which is a part of process of producing the precast type concrete block 100 which concerns on Example 1, and shows another Example of the arrangement | positioning method of a permeable sheet. It is a figure showing the surface in which the recessed part by a bubble has generate | occur | produced.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Precast type concrete block 10 Side wall part 20 Upper surface plate part 21 Inner wall surface 30 of an upper surface plate part Penetration sheet 50 Form 51 Outer type 52 Core type

Claims (3)

A precast-type concrete block, wherein a permeation sheet made of a nonwoven fabric, paper, woven fabric, knitted fabric or the like capable of permeating concrete is embedded in at least a part of the surface of the concrete block molding surface or in the vicinity below the surface. 2. The precast concrete block according to claim 1, wherein the permeation sheet is embedded in a surface of a surface of the concrete block that is formed by arranging a mold on the upper surface when the concrete block is manufactured. Arrangement of permeation sheets such as non-woven fabric, paper, woven fabric, knitted fabric, etc. in which ready-mixed concrete can permeate at least on the molding surface forming the lower surface of the outer mold, core mold, etc.
Pour the ready-mixed concrete into the mold, and after removing the mold,
A method for producing a precast concrete block in which a permeation sheet made of non-woven fabric, paper, woven fabric, knitted fabric, etc., through which ready-mixed concrete can permeate, is embedded in at least a part of the molding surface of the concrete block or in the vicinity below the surface. .

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