JPH0130986B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gypsum board casting form used for rationally and economically finishing the surface layer of a concrete structure with gypsum board, and a concrete construction method using the same.

Conventionally, plywood, aluminum, iron, etc. have been mainly used as concrete formwork materials. However, although aluminum and iron materials have the advantage of finishing accuracy and long formwork life, they are difficult to process on site and are used for complex structures such as columns and beams, air conditioning ducts, and penetrations for water, gas, and electric wires. It has the disadvantage that it is unsuitable for processing and is expensive. On the other hand, wood-based formwork materials such as plywood,
Currently, it is most commonly used because it is lightweight, easy to work with, and easy to nail and saw, taking advantage of wood's high tensile strength and comparative properties.
However, using these wood-based formworks is difficult because oil treatment and cleaning work for peeling is difficult, and water absorption from concrete and strong alkalinity cause warping or deformation during nailing and demolding, etc., resulting in repeated use. This method has disadvantages such as being limited to about 2 to 4 times.

As an alternative to the conventional concrete formwork materials mentioned above, gypsum board (i.e., gypsum mixed with fibers such as sawdust), which is produced in large quantities as a by-product of the petrochemical industry and whose quality is stable, has recently become available. It has also been proposed to use plaster (a board material made by sandwiching plaster between cardboard-like reinforced paper and hardening) as a formwork material (for example, in ``Architectural Technology'').
1980.4, No. 344, pp. 131-136). The use of gypsum board as a formwork material is not only economical, but also has excellent workability, such as being easy to process with a cutter knife, and is virtually non-stretchable compared to wooden formwork. It has the advantage of good dimensional stability.
However, according to research conducted by the present inventors, the following problems were found in using such a gypsum board as a molding form.

(a) Reinforced paper used for gypsum board has a high water absorbency, and its water absorption cannot be suppressed by applying paraffin, and it deteriorates when it comes into contact with strongly alkaline concrete.

(b) Lateral pressure during concrete placement causes initial deformation and creep deformation.

(c) During demolding, peeling may occur not only at the interface between the concrete and the gypsum board, but also at the interface between the gypsum board and the reinforced paper.

In the course of further research into the use of the above-mentioned gypsum board formwork, the present inventors noticed that gypsum board is often attached to concrete structures as a surface finishing layer (usually a base layer). Conventionally, such a gypsum board finish layer is provided by first forming a concrete structure using a formwork, then pasting it on top of it with an adhesive, etc., and then applying various types of decorative paper, etc. on top of it. It is used to give interior walls and other surfaces a decorative finish by pasting or painting. however,
By using the gypsum board formwork as a cast formwork that remains in the concrete instead of removing it after concrete is placed like normal formwork, the above-mentioned use of the gypsum board formwork is achieved. It has been found that the problem (c) has been solved, the requirements regarding the durability of the formwork have been eased, and furthermore, the above-mentioned gypsum board surface-finished concrete structure can be manufactured all at once. And the problem with (b) above is,
Rather than supporting the lateral pressure of the concrete with the gypsum board itself, the gypsum board should be made thinner to give it some flexibility, and the lateral pressure of the concrete can be supported by a reinforcing plate on the back side of the gypsum board. It is advantageous both economically and in that warping of the gypsum board itself can be corrected using lateral pressure during concrete pouring. In order to use gypsum board as a cast formwork in this way, it is necessary to give the gypsum board adhesion to concrete rather than releasability, and to form a separate water-stopping layer to solve the above problem (a). It is preferable to eliminate it.

The gypsum board casting form for concrete placement of the present invention is based on the above-mentioned knowledge, and more specifically, a rough sheet having water-stop properties and adhesion to concrete is pasted on one side of the gypsum board. It is characterized by: Further, the concrete construction method of the present invention includes placing a back support on the opposite side of the gypsum board formwork to which the rough sheet is attached, and pouring concrete on the rough sheet side.
This method is characterized by removing the back support after the concrete has hardened.

Hereinafter, the present invention will be explained in more detail with reference to the drawings. In the following description, "%" and "part"
is based on weight.

FIG. 1 shows a conceptual laminated structure of an embodiment of the gypsum board casting form of the present invention, and the casting form A has waterproof properties and concrete adhesion on one side of the gypsum board 1. A rough surface sheet 2 having a rough surface is pasted thereon. The gypsum board 1 is made by mixing calcined gypsum or hemihydrate gypsum with wood fibers such as sawdust or reinforcing fibers such as glass fibers and kneading it with water. (1b is the cured substrate of the gypsum compound).
As such gypsum board (as is clear from the above definition, it includes what is generally called glass fiber reinforced gypsum board (GRG)), commercially available gypsum boards can be used as they are, but for the purpose of the present invention For this reason, it is preferable to use paper having an average thickness of 3 to 30 mm (error within ±3 mm) including the reinforced paper 1a. If the thickness is less than 3 mm, it will be difficult to handle due to poor impact resistance, and if it exceeds 30 mm, it will be too heavy and will be difficult to handle, and it will be economically unsuitable. 3~9mm
(error within ±3 mm) gypsum board is particularly preferably used.

As shown in FIG. 1, the rough sheet 2 has water-stop properties by itself, and as shown in FIG. (The laminated structure is not shown in the drawings) and has water-stop properties in combination with this water-stop layer.

Examples of the rough sheet 2 which has water-stop properties by itself include polystyrene, polyethylene, polypropylene, vinyl chloride resin, cellulose acetate, polyurethane, area resin, acrylic resin,
Examples include various plastics such as epoxy resins and silicone resins, and rubber foams (generally referred to as plastic foams). The reason why these plastic foams form an adhesive layer with poured concrete is that the exposed air bubbles of the foam, which is a porous material, are filled with cement, creating a mechanical anchoring effect. ~4
Adhesive strength of Kg/cm ² can be obtained. In order to have affinity with concrete, about 2 to 70 parts of inorganic powder can be added to each 100 parts of each resin. As the inorganic powder, calcium sulfate, calcium carbonate, magnesium oxide, calcium oxide, aluminum oxide, titanium dioxide, magnesium sulfate, aluminum sulfate, calcium hydroxide, aluminum hydroxide, etc. can be used, and among them, magnesium oxide and magnesium sulfate are used. preferable. When blending the above inorganic powder with each of the above resins, the blend can be stabilized by adding unsaturated aliphatic carboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, acrylic acid, or their anhydrides as blending aids. can be done.

Further, in order to improve the affinity between the above-mentioned resin and concrete, surface treatments such as flame treatment and corona discharge treatment may be performed, and these surface treatments and the above-mentioned blending of the inorganic powder may be used in combination.

The plastic foam itself is preferably made of closed cells and has an expansion ratio of about 5 to 40 times in order to provide a sheet that has low hygroscopicity and has good adhesion to concrete. Among the above plastic foams, polyethylene foam is most preferred because it can be easily formed into a thin sheet and has excellent non-water absorbing properties, weather resistance, chemical resistance, and especially alkali resistance.

These plastic foam sheets 2 are formed by foam extrusion lamination on the gypsum board 1,
Alternatively, it can be formed by once forming a plastic foam sheet and then melting one side of the sheet and attaching it to a gypsum board. Rubber adhesives such as nitrile rubber, styrene butadiene rubber, and natural rubber; polyvinyl acetate resin, acrylic resin, ethylene-vinyl acetate copolymer resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyvinyl chloride resin, Thermoplastic synthetic resin adhesive such as polyamide resin; thermosetting synthetic resin adhesive such as phenol resin, resorcinol resin, urea resin, melamine resin, unsaturated polyester resin, polyurethane resin; or adhesive such as asphalt. Good too.

On the other hand, examples of the rough sheet 2a which does not have waterproof properties by itself include natural fibers such as cotton; chemical fibers such as rayon and acetate; synthetic fibers such as nylon, acrylic, polyester, vinylon, and polypropylene; rock wool; Alkali-resistant glass wool, nonwoven fabrics such as asbestos and other mineral fibers, spunbond, woven fabrics, knitted fabrics, flocked fabrics, or synthetic papers, as well as kraft paper, Darpolin paper, felt, and other sheet materials made of intertwined various alkali-resistant fibers. is used. As in the case of the above-mentioned plastic foam, these fiber sheet materials also have a concrete composition filled in the gaps between the entangled fibers, and have good adhesion to concrete due to its anchoring effect. Alternatively, plastic foam having open cells can also be used.

These rough fibrous sheets 2a have poor water-stopping properties by themselves. Therefore, as shown in FIG. 2, it is necessary to separately attach the gypsum board 1 via a water-stop layer 2b to provide water-stop properties.
Such a water stop layer 2b can be formed by pasting a water-impermeable sheet such as plastic film or aluminum foil together with a plasterboard when forming the sheet 2a in advance, or by bonding it to a gypsum board. It can also be obtained by laminating the fiber sheet 2a and the gypsum board 1 via a melt-extruded film of a hydrophobic thermoplastic resin, in which case the thermoplastic resin film as an adhesive layer also acts as a water stop layer. . In addition, asphalt is also used as an adhesive suitable for bonding a fiber sheet to a gypsum board and capable of forming a water-stop layer. Furthermore, for materials that have already been waterproofed, such as waterproof paper for plastering, the formwork material of the present invention can be obtained by bonding the waterproof surface of the paper to a gypsum board using a suitable adhesive. In addition, it is not inconceivable that the above-mentioned water-stopping layer may be produced by forming reinforcing paper 1a in advance, and then sandwiching and curing the gypsum paste to produce a gypsum board having a water-stopping layer. If you do this, you will not be able to obtain a gypsum board with a uniform thickness, and the subsequent warping will be large.

For the purposes of the present invention, the thickness of the roughened sheet 2 (or 2a+2b) is between 0.005 and 100 mm, especially 0.02
A range of ~20 mm is preferred. If it is less than 0.005 mm, the anchoring effect due to cement filling will not be sufficient or
If it exceeds 100 mm, it will be economically disadvantageous.

As shown in FIG. 3, a primer layer 3 may be further provided on the contact surface of the above-mentioned formwork material with the concrete to further improve the adhesion strength with the concrete. As the primer used for this purpose, those based on ethylene-vinyl acetate copolymer resins or those generally commercially available as mortar adhesion enhancers are suitably used. More specifically, resin emulsions such as phenolic resins, ethylene-vinyl acetate copolymers, acrylics, and acrylic-styrene copolymers, cationic SBR latex, and solutions of methyl cellulose, polyvinyl alcohol, or vulcanized rubber, etc. or a mixture thereof with one or more types of inorganic particles or powders such as cements, talc, limestone, silica, sand, and crushed stone in an amount of 0.3 to 500 parts per 100 parts of resin is used. These primers can be used as a resin solid content of 3.
It is applied at a rate of ~500g/ ^m2 .

The driving formwork of the present invention can be manufactured by using the above-mentioned laminated formwork materials as they are, or by processing them into a suitable shape with a cutter knife or the like and then combining them.

Next, a concrete construction method using the gypsum board casting form of the present invention as described above will be explained.

For example, to explain the manufacture of the inner wall of a typical building with reference to FIG. Then, the back reinforcing plate 6 is placed along the exposed back surface of the gypsum board 1 and fixed in the same manner. On the other hand, a formwork B (which can also be the casting form A of the present invention) is provided opposite to the surface of the casting formwork A on which the rough sheet 2 is provided, and a concrete composition is placed in the gap between the two formworks. 8. After the concrete has hardened, by removing the opposing formwork B and the back reinforcing plate 6, an inner wall structure as shown in FIG. It will be done.

As mentioned above, the gypsum board formwork of the present invention is relatively thin and cannot support the lateral pressure of concrete by itself, and on the contrary, it has some flexibility due to its thinness. Therefore, the back reinforcement plate 6
has the function of supporting the lateral pressure of concrete transmitted through this formwork A. As described above, in the concrete construction method of the present invention, the gypsum formwork itself does not require much strength, so the height of the concrete structure is restricted by the strength limit of the gypsum formwork (because the lateral pressure of the concrete is Wall structures of arbitrary height and width can be obtained without the pressure acting on the formwork proportional to its height and being greatest near the bottom. this is,
Conventionally, when using plaster formwork, the height of the concrete structure obtained was 45 to 60 mm due to its strength constraints.
It can be said that this is a dramatic improvement compared to when we were only able to obtain something similar to cm and the basics of a house.

The back reinforcing plate or material 6 can be any material as long as it is a substantially rigid body that has the strength to support the lateral pressure of concrete; for example, like formwork B, it may be made of conventional plywood, aluminum material, or steel material. Formwork materials such as or honeycomb materials are also used.

When fixing the driving formwork A to the foundation 5, a jig for this purpose and a water stop treatment at the joint between the formwork A and the foundation 5 are required. Various joint structures can be considered for this purpose, but for example,
As shown in the figure, it is conceivable to prepare a formwork in which the waterproof roughened sheet 2 is extended to the bottom end face of the gypsum board 1, and to fix this to the floor 5 with L-shaped fixtures 9. In such a case, it is also possible to separately prepare a water-stopping layer 10 made of a foamed plastic sheet or the like, join the bottom surface of the formwork A to this, and fix it with an L-shaped fixture 9 or the like (see Fig. 7). ). As shown in FIG. 8, a more preferable embodiment is a guide rail 11 made of a plastic molded body or an alkali-resistant metal molded body, which has the effect of positioning and fixing the formwork and stopping water at the joints.
The bottom of the formwork A is accommodated in the groove of the guide rail 11 via a water-stopping sheet layer 12 preferably made of a foamed plastic sheet or the like. This guide rail 11 preferably has three boundary walls 11a, 11b, and 11c that are substantially perpendicular to the foundation surface 5, and accommodates the bottom of the formwork A in the groove between the boundary walls 11a and 11b. The bottom part of the back reinforcement support 6 is accommodated in the groove between 11c. After pouring the concrete 8, when the back reinforcing support 6 is removed, the boundary wall 11c will protrude from the foundation, but such small protrusions should be sufficiently hidden with mortar or plaster pouring material, flooring material such as carpet or tile, etc. There is no problem because it can be done. On the other hand, pouring formwork A
It is extremely convenient if the border wall 11b adjacent to the border wall 11b is made relatively high so that it can be used as a baseboard as it is.

Formwork A can be easily obtained with a considerable width, for example, 1200 x 2400 mm. However, when finishing a nice wide wall, or when using unit formwork with a narrow area for decorative effects or other reasons, these unit formworks A are connected two-dimensionally to create a wide formwork, as shown in Figure 9. It is necessary to construct a frame. In such a case, the connecting portion 13a,
13b, 13c, etc., tend to cause problems such as a decrease in strength and finish accuracy due to deflection, and water leakage. For this reason, it is advisable to use a back reinforcing plate 6 in addition to the one used at the bottom for reinforcement at these connecting parts, if necessary. It is not necessarily necessary to reinforce all the connecting parts 13a to 13c, but in that case, the connecting parts 13 of three or more formworks
Reinforcement may be performed in the order of priority: c, vertical connecting portion 13c, and horizontal connecting portion 13a.

In addition, the water-stopping effect at the joints is enhanced and the formwork A
For the purpose of preventing peeling between the hardened concrete 8a and the hardened concrete 8a, at least one part of the formwork A is
A form board AA is used in which the rough surface sheet 2 is made longer than the plasterboard 1 to form side pieces 2c and 2d at the ends of the directions (two directions in FIG. 10, but up to four directions are possible). It is preferable. A pair of such formwork boards A are connected as shown in FIG. 11, one side piece 2c is folded into the end face of the plasterboard 15, and glued as necessary (preferably glued in advance). The end face of the other gypsum board 16 is brought into contact with this, and the side piece 2d of the gypsum board 16 is overlapped with the rough sheet 21 on the gypsum board 15.
In this way, the side pieces 2d are pressed against the roughened sheet 21 by the lateral pressure exerted by the concrete 8 being cast, and the water-stopping property at the joint is significantly improved along with the presence of the side pieces 2c between the end faces. Further, by providing several holes 2e in the side piece 2d by punching or the like, the concrete hardens through these holes and has an anchoring effect, so that peeling between the formwork A and the hardened concrete becomes less likely to occur. A similar effect can also be obtained by making some cuts in the side piece 2d. If necessary, the side pieces 2d may be temporarily fixed to the rough surface sheet 21 using staples or the like before concrete placement. Note that the use of the guide rail 11 explained with reference to FIG. 8 is also effective for holding down and fixing such side pieces at the bottom of the formwork. Furthermore, although the water stop prevention effect is considerably reduced (although it still exists to some extent), in the sense of improving the adhesion strength with the hardened concrete, it is possible to cut the side pieces 2c and 2d of the formwork material shown in Fig. 10. Alternatively, if a fibrous rough-surfaced sheet 2 is used, its ends are defibrated to form whiskers or thin strip-like ends 2f and 2g, and these are beaten as shown in FIG. It can also be buried in the concrete layer 8.

A decorative wall is further formed on the gypsum board surface of the resulting inner wall structure shown in FIG. 5 by pasting cloth or vinyl cloth, decorative cloth, decorative paper, or painting. One of the important advantages of the concrete construction method of the present invention is that decorative finishing can be performed immediately after concrete is poured and hardened. In contrast, conventionally, after obtaining the concrete frame, it was necessary to prepare the base by adhering gypsum board using a so-called "direct adhesive bond" and then apply a decorative finish.

When plastic foam is used as the roughened sheet in the above, since the plastic foam has heat insulating properties, it is possible to construct a wall surface that has the following advantages over a conventional wall in which a heat insulating material is poured. Conventionally, for example, a polystyrene foam or polyurethane foam material with a thickness of about 30 mm was placed inside the plywood form and concrete was poured.
A gypsum-based adhesive called "direct adhesive bond" is deposited thickly on the surface of the foam material in spots of 150 to 350 mm, and a gypsum board is pasted on the surface, or "direct adhesive adhesive" is applied to the surface of the concrete structure. In the same way, plasterboard with a foam material on the back is applied with a thick layer of "direct adhesive bond", but with either method, 20% Since it has an air layer of about 25 mm, it has the disadvantage that mold and stains due to dew condensation can reach the decorative surface. However, in the present invention, such a "direct adhesive bond" is not used, and therefore there is no air layer, so no condensation occurs, and furthermore, it has water-stopping properties, so there are no drawbacks such as mold or stains. It does not reach the surface. This effect of the present invention can be achieved by using a thick plastic foam, and by extending the ends of the plastic foam as explained using FIGS. 6 to 8 and FIGS. 10 and 11. This is especially noticeable when water-stopping treatment is applied to the ends, such as by wrapping the ends in the water.

In the above, the application of the construction method of the present invention to side chains has been explained. However, in the method of the present invention, almost no strength is required of the formwork itself, so construction of ceilings, floors, etc. can be similarly facilitated. In addition, concrete structures are not directly formed on-site as described above, but are obtained in a factory using concrete structural materials with plasterboard attached to the surface in substantially the same manner as above, and then transported to the site. Needless to say, an assembly method is also possible.

As described above, according to the present invention, it is possible to manufacture a gypsum board casting form for concrete placement that has excellent water-stopping properties and adhesion to concrete, and a concrete structure having a simple gypsum board finishing layer using the same. method (i.e. concrete construction method)
is provided. As is clear from the above, there are many advantages of the casting formwork of the present invention and the construction method using the same, but they can be summarized as follows.

(b) It has stable quality as a formwork, and has good workability and dimensional stability.

(b) Since the formwork is poured, there is no need for chiseling work after pouring.

(c) For example, 4×8
Formwork of large dimensions such as shaku can be easily cut.

(d) Since it is thin, it has a light weight per unit area and is economically advantageous.

(E) After the concrete is poured and hardened, the gypsum board base is formed at the same time, so decorative finishing such as cross-laying, painting, tiling, etc. can be easily performed.

(f) There is no staining due to wood scum, stains, sap, oil, etc. when using wooden formwork, and no staining due to rust, scum, oil, etc. when using metal formwork.

(G) By making the plates larger, the joints are reduced and the holo area, which is the weak point of plaster, can be reduced.

(h) As a result of water stop treatment, interaction between gypsum and concrete is suppressed, and embrittlement due to concrete neutralization can be prevented.

[Brief explanation of drawings]

FIGS. 1 to 3 are partial sectional views showing a conceptual laminated structure of an embodiment of the casting formwork of the present invention, and FIG.
5 and 5 are cross-sectional views in the thickness direction of the formwork to explain the steps of the concrete construction method of the present invention using the same formwork, and FIGS. 6 to 10 respectively show the fixing structure at the bottom of the formwork. 9 is a side view showing an additional mode of use of the back support, FIG. 10 is a partial sectional view of another example of the formwork of the present invention, and FIGS. 11 and 12 are It is a partial sectional view showing the state of connection between a pair of formworks performed using such a formwork. 1, 15, 16... Gypsum board (1a... Reinforced paper, 1b... Gypsum base material), 2... Rough surface sheet, 3
... Primer layer, 5 ... Foundation, 6 ... Back support, 8 ... Concrete composition (8a ... after curing), 11 ... Guide rail (11a, 11b,
11c...boundary wall), 13a, 13b, 13c...
Formwork connection part, 2c, 2d...side piece, 2e...through hole, 2f, 2g...beard-shaped or thin strip-shaped end,
A...Gypsum board cast formwork, B...Formwork.

Claims (1)

[Scope of Claims] 1 A formwork comprising a roughened sheet having both water-stop properties and adhesion to concrete adhered to one side of a gypsum board, the formwork having the following configuration: A gypsum board pouring formwork for concrete pouring. (a) The rough-surfaced sheet is a fiber sheet made of intertwined alkali-resistant fibers, and has water-stop properties by being adhered to the gypsum board via a water-stop adhesive layer. (b) At least one end of the formwork, the roughened sheet is longer than the gypsum board and forms an unrestricted side piece. (c) The unrestricted side piece of the rough sheet has a plurality of through holes formed by punching. 2. The gypsum board has an average thickness of 3 to 30 mm,
The formwork according to claim 1. 3. The gypsum board has an average thickness of 3 to 9 mm,
The formwork according to claim 1. 4. A patent claim in which side pieces are formed at the ends of the formwork in at least two directions, one of the side pieces is adhered and fixed to the end face of the gypsum board, and the remaining side pieces form unrestricted side pieces. The formwork for the first term in the range. 5. The formwork according to claim 1, wherein the roughened sheet is longer than the gypsum board at an end portion in at least one direction of the formwork, and has a whisker-like or thin strip-like end portion. 6. A back support on the opposite side of the gypsum board casting formwork, which is made by pasting a rough sheet with waterproof properties and adhesion to concrete on one side of the gypsum board, to which the rough sheet is pasted. A guide rail having a groove for accommodating the bottom of the formwork is fixed to the joint between the foundation and the driving formwork, and the bottom of the formwork is accommodated in the groove via a water-stopping sheet layer. After fixing, concrete is poured, and after the concrete has hardened, the back support is removed, and one of the pair of boundary walls that forms the groove for the guide rail that accommodates the bottom of the formwork, on the side opposite to the poured concrete. A concrete construction method characterized in that the boundary wall forms a baseboard after construction. 7. Enforcement law of claim 6, in which the guide rail is made of plastic or an alkali-resistant metal molded body.