JPH10184002A - Space-forming member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily remove a plug body, by covering at least a part of a plug body for forming a space with a water-absorbing sheet to shape a space-forming material. SOLUTION: A through hole 6 connecting both end faces 4, 5 is formed along the nearly axial direction, in a plug body 1. And a pipe 7 is projected from the through hole 6. A base material sheet is formed with non-woven cloth made of hydrophobic fiber such as polyester, polypropylene, etc., for instance. A water-absorptive polymer is prepared by polimerizing a water-soluble ethylene unsaturated monomer which is chiefly composed of acrylic acid, acrylic acid salt, or (metha) acrylic acid containing sulfonic acid radical or the salt thereof, or to which a bridging agent is added as the case may be. And this polymer is fixed to a base material to form a water-absorptive sheet 2. And further, the plug body 1 is covered with the sheet 2 to shape a space-forming material 3. In this way, since the sheet 2 gets swelled and a gel layer is formed, the plug body can be easily removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for forming voids in a cured product (concrete) of a water-curable composition such as cement milk. More specifically, after a plug having the same shape as that of a cured body (concrete) void of a water-curable composition such as cement milk is installed in a water-curable composition such as ground or cement, after a lapse of time, The present invention relates to a gap forming material that forms a target gap by removing a plug.

[0002]

2. Description of the Related Art It is necessary to form various kinds of voids required for post-processing, cavities and voids for passing wirings and pipes inside and outside the foundations and walls of civil engineering and buildings. Conventionally,
As the foundation pile driving method, a driving pile method was used in which the foundation pile was driven directly into the underground supporting ground until the tip penetrated, but this method generated a large vibration and impact sound,
It is becoming an unfavorable construction method due to environmental problems.

[0003] The method of embedding foundation piles has spread instead. In this method, after excavating the ground to a predetermined depth using an excavator such as an earth auger, cement milk is injected into the excavation hole, and then an open-end hollow concrete pile is buried in the hole, and a foundation pile is formed. Is what you do. In this method, when embedding the pile, it is easy for cement milk to rise to the head of the pile and fill the space above the pile, and after hardening of the cement milk, a reinforcing steel cage for connection to the base is installed. It is necessary to form a space in the pile head by filing work or the like so that it can be inserted.

In order to form this space, a filler such as a paper tube, a metal body, or a synthetic resin molding is attached to a pile head,
After the cement has hardened, a method of forcibly removing the filler by using a heavy machine or a method of dissolving a synthetic resin molded product with a solvent have recently been developed.

However, since a great deal of power is required to forcibly remove the filler, a special heavy machine is indispensable, and there are problems in terms of complexity and safety. Also,
In a site with a small work space, heavy equipment could not enter, and it was sometimes impossible to remove the filler. In addition, the removed packing had to be treated as waste.
On the other hand, when the worker removes directly, it is extremely difficult and complicated to crush the hardened cement.Therefore, there is a problem that the working efficiency is poor and the construction period is prolonged. Care needed to be taken.

Therefore, in order to reduce such filing work, Japanese Patent Application Laid-Open No. Hei 4-922015 discloses a hollow body of a pile head made of a cylindrical body such as expanded polystyrene having a powdery water-absorbing polymer applied to the inner and outer surfaces. Insertion methods have been proposed. This is a method for preventing the cement from adhering to the inner wall of the pile by preventing the cement from adhering to the inner wall of the pile due to the water-absorbing polymer absorbing and swelling the moisture of the cement milk.

However, according to this method, in order to fix the water-absorbing polymer on the surface of the cylindrical body, it is necessary to form a coating film using a coating medium or a bonding agent such as a binder. Although the film of the bonding agent to be formed contributes to fixation of the water-absorbing polymer, water absorption of the water-absorbing polymer,
This significantly limits the swellability, and if the amount of the bonding agent is small, the polymer will fall off. Further, the adhesion distribution of the polymer was likely to be uneven. Therefore, even if pure water has a water absorption ratio of several tens of times, the water in cement milk has a high salt concentration, so its water absorption becomes extremely low, and the adhesion of cement to the pile inner wall is completely eliminated. It was not something that could be prevented. Further, the process of applying the water-absorbing polymer to the surface of the cylindrical body itself is extremely troublesome, and the work of fraying the cement flowing into the inside of the cylinder is still indispensable and complicated. This publication also proposes a method of applying a water-absorbing polymer to the inner wall surface of the pile. However, according to this method, since it is difficult to remove the coating film, the coating film remains on the inner wall surface of the pile even after the void is formed in the pile head,
There is a problem that the adhesion strength between the reinforcing steel member for the base inserted into the void hole of the pile head and the pile is reduced.

In Japanese Patent Application Laid-Open No. Hei 4-333770, a water-absorbing and swelling material itself in which a water-absorbing polymer is blended with rubber or soft resin is used as a mold material, and the water-absorbing and swelling material is sufficiently absorbed and swelled into concrete (not yet). During curing, the concrete is cured and dried, and then cured, and then the water-swellable material that has dried and shrunk is removed to form a cavity in the concrete.

However, also in this method, as in the case of the former publication, the water-absorbing polymer is mixed with a substance that suppresses the water-absorbing and swelling properties of the water-absorbing polymer such as rubber or soft resin. It was low.
Therefore, it is difficult to sufficiently swell by absorbing water having a high salt concentration in concrete, and it is preferable to sufficiently absorb pure water in advance to cause swelling. It took a lot of time to swell to the size required. Further, another mold material for controlling to a predetermined size and shape has been required.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate the need for a special heavy machine, to greatly facilitate the removal of a filler (plug) used for forming a gap, and to form a gap on site. An object of the present invention is to provide a void-forming material that makes the operation extremely simple and reduces the amount of waste material by reusing the filler (plug).

[0011]

The above objects are achieved by the following (1) to (3).

(1) A material for forming a void for installing a structure, wherein at least a part of the void forming plug is covered with a water-absorbing sheet.

(2) The void-forming material according to (1), wherein the water-absorbent sheet is obtained by polymerizing a polymerization component containing a water-soluble unsaturated monomer on a substrate.

(3) The void forming member according to (1) or (2), wherein the void forming plug has at least one through hole formed to communicate with both end surfaces substantially in the axial direction. Wood.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 and FIG. 2 show an embodiment of a void forming material for a cured product of the water-curable composition according to the present invention. That is, a cylindrical void-forming plug 1,
A gap forming material 3 comprising a water-absorbing sheet 2 covering at least the outer surface of the gap forming plug 1, for example, as shown in FIGS. The gap forming plug 1 may be provided with a through hole 6 communicating with both end faces 4 and 5 substantially along the axial direction, if necessary. The through-hole 6 is formed by forming a cavity in the plug 1 for forming a void, and inserting a pipe 7 with its tip protruding. Although one through hole 6 is usually sufficient, a plurality of through holes 6 may be provided in the case of the large void forming plug 1.

Further, the water-absorbent sheet 2 which has been swollen later.
In order to facilitate the removal, a string 8 may be attached to each end of the water absorbent sheet 2.

FIG. 3 shows another embodiment of the void-forming material according to the present invention. In the void-forming material 3 having the same structure as that shown in FIGS. This shows an example in which a pipe is not inserted into a through hole 6 provided along the axial direction. Note that, in the figure, the same reference numerals as those in FIGS. 1 and 2 indicate the same members.

FIG. 4 shows still another embodiment of the void forming material according to the present invention. In the void forming material 3 having the same structure as that shown in FIGS. It is formed by the body. In this case, the through hole 6
The pipe 7 is inserted as necessary with its tip protruding. Note that, in the figure, the same reference numerals as those in FIGS. 1 and 2 indicate the same members.

FIG. 5 shows another embodiment of the void forming material according to the present invention, in which the void forming plug 1 is formed of a bottomed cylindrical body. Note that, in the figure, the same reference numerals as those in FIGS. 1 and 2 indicate the same members.

FIG. 6 shows still another embodiment of the void forming material according to the present invention, wherein the void forming plug 1 is formed of a bottomless cylindrical body. In this case, the water-absorbent sheet 2 covers both the inner and outer surfaces of the bottomless cylindrical body. In addition,
In the figure, the same reference numerals as those in FIGS. 1 and 2 denote the same members.

FIGS. 7 and 8 show another embodiment of the void forming material according to the present invention, which is an example of a split type in the case of a large void forming material. That is, for example, as shown in FIG. 7, a column-shaped plug 1 for forming a void having a fan-shaped cross section.
And a bag-shaped water-absorbing sheet 2 covering at least the outer surface of the space-forming plug 1, for example, as shown in FIG. The gap forming plug 1 may be provided with a through hole 6 communicating with both end faces 4 and 5 substantially along the axial direction as necessary.
Alternatively, a pipe (not shown) may be fitted with its tip protruding further.

Further, the water-absorbent sheet 2 which has been swollen by water later.
In order to facilitate the removal, a string 8 may be attached to each end of the water absorbent sheet 2.

The void forming material 3 having such a structure is as follows.
A plurality of, for example, three are combined and used as shown in FIG. 8 to form a columnar or cylindrical shape.
Thus, in the embodiment of FIGS. 7 and 8, an example in which three divided members are combined is shown, but the gap forming material 3 is formed in two or several divisions according to a desired gap size. , May be used in combination.

In the above, the embodiment in which the cross section is circular has been described. In addition to this, polygons such as ellipse, triangle, quadrangle, hexagon, octagon, trapezoid, star, irregular shape, etc. There is a combination of these shapes and the like, and a shape having a shape whose longitudinal section attenuates as the width decreases downward facilitates removal of the plug, and examples thereof include an inverted truncated cone. The shape of the void forming plug is not particularly limited as long as it is easily removable.

However, from the viewpoint of workability such as workability and weight reduction of the void forming plug, a cylindrical or bottomed cylindrical or hollow body is preferred. In the case of a bottomed cylindrical body,
It may be used with a lid, and air, water, a lightweight material, or the like may be filled in the cavity of the bottomed cylindrical body or the hollow plug. This makes it easier to remove the plug.

The water-absorbing sheet used in the present invention is a sheet in which a water-absorbing polymer is directly fixed to a sheet-like substrate.

As the water-absorbing polymer in the present invention,
For example, it is obtained by polymerizing a water-soluble ethylenically unsaturated monomer containing acrylic acid or an acrylate or a (meth) acrylic acid ester containing a sulfonic acid group or a salt thereof as a main component and optionally adding a crosslinking agent. And a water-absorbing polymer that absorbs and swells water 10 to 1000 times its own weight, and is preferably used.

Examples of water-absorbing polymers other than those described above include:
For example, cross-linked polyvinyl alcohol, cross-linked polyethylene oxide, cross-linked polyvinyl pyrrolidone, cross-linked sulfonated polystyrene, cross-linked polyvinyl pyridine, starch-
Saponified poly (meth) acrylonitrile graft copolymer, starch-poly (meth) acrylic acid (and salt thereof) graft cross-linked copolymer, reaction product of polyvinyl alcohol and maleic anhydride (salt), cross-linked polyvinyl alcohol sulfonic acid Salts, polyvinyl alcohol-acrylic acid graft copolymers and the like can also be exemplified. Further, a water-absorbing polymer obtained by polymerizing a monomer component having a water-soluble nonionic unsaturated monomer as an essential component is exemplified.

Examples of the sheet-like substrate used in the present invention include hydrophilic or hydrophobic porous materials such as woven fabric, nonwoven fabric, knitted fabric, paper, sponge and the like.
It is preferable that the base material has voids therein, because a space allowing swelling of the water-absorbing polymer can be secured and the cement water can effectively contact the water-absorbing polymer. As the material used for the base material, when the base material is a fiber base material, hydrophilic materials include wood pulp, cotton, wool, rayon, acetate, and vinylon, and hydrophobic materials include polyester. , Polyacrylonitrile, nylon, polypropylene, polyethylene, polyvinyl chloride, polyurethane, glass wool, and rock wool fibers. When the base material is sponge-like, examples thereof include polyacetal, polyolefin, polyurethane, cellulose, and phenol resin. Among them,
From the viewpoints of workability, flexibility, and economy of the obtained water-absorbent sheet, it is preferable to use a nonwoven fabric made of a hydrophobic fiber such as polyester or polypropylene as a preferable substrate. Although the thickness of the substrate is not particularly limited, it is generally 0.01
10 to 10 mm, preferably 0.1 to 5 mm. The basis weight is 10 to 500 g / m ^2, preferably 20 to ²⁰ g / m ^2.
The range is 0 g / m ² .

In the present invention, the weight ratio of the water-absorbing polymer to the sheet-like substrate is in the range of 10 to 1000 parts by weight, preferably 80 to 500 parts by weight, based on 100 parts by weight of the substrate. . When the amount of the water-absorbing polymer is less than 10 parts by weight, the lubricating effect at the time of pulling out the plug for forming the void of the water-absorbing polymer is unfavorably small. On the other hand, when the amount exceeds 1,000 parts by weight, the flexibility of the obtained water-absorbent sheet is reduced, which is not preferable from the viewpoint of workability.

As a method for obtaining a water-absorbing sheet in which these water-absorbing polymers are directly fixed to a sheet-like substrate, there is a method of (A) directly pressing a water-absorbing polymer softened with water on a substrate and, if necessary, drying. B) A method in which a water-soluble polymer that can be converted into a water-absorbing polymer by crosslinking is applied to a substrate, and then the crosslinking is performed. C) If the water-absorbing polymer can be directly fixed to the sheet-like substrate without a binder, such as a method of applying a monomer capable of being converted to a water-absorbing polymer by polymerization to a sheet-like substrate and then polymerizing the method, the method is particularly preferable. Not limited.

Above all, from the viewpoint of easiness of production, economy and durability of the obtained water-absorbent sheet, a monomer which can be converted into a water-absorbent polymer by polymerization is adhered to a substrate, and then the monomer is formed into a sheet. A method of polymerizing on a substrate is preferred. According to this production method, a water-absorbing sheet in which a water-absorbing polymer is directly fixed to a sheet-like substrate can be obtained more easily.

Examples of the monomer which can be converted into a water-absorbing polymer by polymerization include acrylic acid, methacrylic acid and their alkali metal salts and ammonium salts; 2- (meth) acryloylethanesulfonic acid,
(Meth) acryloylpropanesulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid,
Vinyl sulfonic acid, (meth) allyl sulfonic acid and their alkali metal salts and ammonium salts; (meth) acrylamide, N, N'-dimethylaminoethyl (meth)
Acrylates and their quaternaries; hydroxyalkyl (meth) acrylates, polyalkylene glycol (meth) acrylates, and the like; one or more of these can be used.

From the viewpoint of swelling property of cement water,
(Meth) acryloylethanesulfonic acid, 2- (meth)
Water-soluble ethylenic acid having a sulfonic acid group such as acryloylpropanesulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, vinylsulfonic acid, (meth) allylsulfonic acid and alkali metal salts and ammonium salts thereof. Saturated monomers are more preferred. The pore-forming material of the present invention using a water-absorbing sheet obtained by adhering a water-soluble ethylenically unsaturated monomer having a sulfonic acid group to a substrate and polymerizing / crosslinking the same is a polyvalent material such as calcium contained in cement water The water-absorbing polymer of the present invention can be used as a void-forming material that has high water-absorption swelling property of cement water even for a long period of time because it is hardly affected by metal salts and pH, and that pulls out the void-forming plug more easily. It can also be obtained by polymerizing a monomer component essentially comprising a water-soluble nonionic unsaturated monomer in the presence of a crosslinking agent if necessary. Examples of the water-soluble nonionic unsaturated monomer include (meth) acrylamide such as acrylamide, methacrylamide, (meth) acryloylmorpholine, diacetone (meth) acrylamide, N-isopropyl (meth) acrylamide, and N, N′-dimethyl (meth) acrylamide. And its derivatives; polyalkylene glycol (meth) acrylates represented by polyethylene glycol (meth) acrylate and methoxy polyethylene glycol (meth) acrylate; hydroxy represented by hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate Alkyl (meth) acrylate; N- represented by N-vinylpyrrolidone and N-vinylsuccinimide
Vinyl monomer; N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide,
N-vinyl amide monomers such as N-vinyl-N-methylacetamide; vinyl methyl ether;

Among them, one or more selected from acrylamide, methacrylamide, methoxypolyalkylene glycol and hydroxyalkyl (meth) acrylate are preferred.

In the present invention, a water-soluble anionic monomer or a water-soluble cationic monomer can be used in addition to the water-soluble nonionic unsaturated monomer.

The water-soluble anionic unsaturated monomers used include acrylic acid, methacrylic acid, 2- (meth)
Acrylamide-2-methylpropanesulfonic acid, 2-
Sulfonic acid group-containing (meth) acrylates represented by sulfoethyl (meth) acrylate and the like, and alkali metal salts or ammonium salts thereof are exemplified.

Examples of the water-soluble cationic unsaturated monomer include N, N'-dimethylamino (meth) acrylate and amino group-containing (meth) acrylate represented by a quaternized product thereof.

Among these monomers, acrylic acid, methacrylic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid are preferred in terms of the water-absorbing performance of the resulting water-absorbing polymer and the pull-out performance of the plug for forming a void. -It is preferable to copolymerize a water-soluble anionic unsaturated monomer such as sulfoethyl (meth) acrylate and its alkali metal salt or ammonium salt with the water-soluble nonionic unsaturated monomer.

It is preferable that the water-soluble nonionic unsaturated monomer is used in an amount of 10 mol% or more, preferably 20 to 99 mol%, more preferably 50 to 95 mol% in the monomer component. The ratio of nonionic unsaturated monomers is 10 mol%
If the amount is smaller than the above, when a steel stopper is used, rust is likely to be generated on the surface of the steel material, which may not be preferable in terms of pullability and reuse of the drawn steel material. And sufficient water absorption performance may not be exhibited in cement water, or water absorption performance may be significantly reduced with time. Also,
If the proportion of the nonionic unsaturated monomer is more than 99 mol%, the resulting water-absorbing polymer may have a low water absorption capacity, and may not be able to exhibit sufficient lubricity in cement water or soft ground.

The void-forming material of the present invention is provided with a water-absorbing sheet containing a water-absorbing polymer obtained by polymerizing a monomer component essentially containing the water-soluble nonionic unsaturated monomer.

Among the above-mentioned water-absorbing polymers, those obtained by polymerizing a monomer component essentially containing a water-soluble nonionic unsaturated monomer in the presence of a crosslinking agent, if necessary, are preferable.

In the above monomers, divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate,
Triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, A polyfunctional water-soluble ethylenically unsaturated monomer represented by N, N-methylenebisacrylamide, triallyl isocyanurate, trimethylolpropane diallyl ether and the like can be added. The use of a crosslinking agent can improve the durability and shape retention of the obtained lubricant. The amount of the crosslinking agent to be used can be appropriately selected depending on the type of the above-mentioned monomer and polymerization conditions, but is generally in the range of 0.001 to 10 mol% (based on the monomer), preferably 0.01 to 5 mol% ( To monomer).

The method for adhering the above-mentioned monomer to the substrate is not particularly limited. For example, in a state of an aqueous solution, a monomer aqueous solution is printed on the substrate, sprayed, impregnated, or the like.
The monomer can be attached to the substrate by a method such as squeezing after impregnation. The monomer thus adhered to the substrate can be polymerized by a known means to directly fix the water-absorbing polymer to the substrate. As a method of polymerizing, for example, a method using heat, light, an electron beam, ultraviolet light, or the like can be employed. If necessary, a water-soluble radical polymerization initiator such as a persulfate or a water-soluble amino compound and other additives may be added to the aqueous solution of the above-mentioned monomer.

The thus obtained water-absorbent sheet of the present invention has a thickness of 10 to 10,000 μm, preferably 100 to 5,000 μm. That is, if the thickness is less than 10 μm, not only the mechanical strength is insufficient, but also the water absorption is insufficient, so that the lubricating property for pulling out the plug for void formation is insufficient. On the other hand, when the thickness exceeds 10,000 μm, the water-absorbent sheet lacks flexibility.

The material of the plug for forming a void is not particularly limited as long as it can form a void in the structure. For example, iron, zinc, metals such as alloys, natural materials such as wood,
Examples include papers such as cardboard, paper tubes, and void tubes, and various synthetic resins such as vinyl chloride resin, polyethylene, polystyrene, fiber-reinforced plastics, and rubber. From the viewpoints of workability, handleability (light weight), and economy, those foams or porous bodies are preferable.

If the surface of the plug for forming a void has a surface sliding property such as a smooth metal surface or a smooth polymer molded surface, the plug is pulled out from the structure or extruded by air pressure. In the case of extracting, etc., the resistance becomes small, and the workability is improved, which is preferable.

The plug for forming a void may be covered with a covering material having slipperiness in advance. Examples of the coating material having slipperiness include various synthetic films or sheets made of polyethylene, polypropylene, polyester, nylon, Teflon, vinyl chloride, vinylidene chloride, etc., metal foil films such as aluminum foil, metal vapor-deposited films, metal thin plates, etc. Is mentioned. Further, various types of slip agents or release agents may be sprayed or applied to the surface of the plug. A polyolefin film is preferably used from the viewpoint of processability, handleability, and economy. Examples of the method of coating the plug with a coating material having slipperiness include a method of wrapping, sticking, and hitting with a pin-shaped object. Furthermore, use of a shrink film is also preferable from the viewpoint of workability.

The void forming material of the present invention having such a structure is used as follows to form desired voids in the cured product of the water-curable composition.

The structure according to the present invention means materials formed into various shapes used in the field of construction or civil engineering.

First, as shown in FIG. 9 (A), for example, after the void forming material 3 is installed in a hole formed in the soil by excavation, cement milk (fresh concrete) is injected or excavated into the soil 10 by excavation. Cement milk 12 is injected into the formed hole, and after a certain amount is injected, the space forming material 3 is inserted and buried. As a result, the cement milk 12 or the cement milk 12 mixed with earth and sand (not shown) fills the gap between the earth wall and the gap forming material 3. During this time, the water containing the calcium salt and other salts in the cement milk and the water-absorbent sheet 2 come into contact with each other to absorb the water.
Swells.

After the cement milk loses its fluidity or hardens, if the plug 1 for forming a void is pulled up, it can be easily removed due to the slipperiness of the water-absorbing and swollen water-absorbent sheet 2. . In this case, when the through-hole 6 is provided in the gap forming plug 1, when the embedded gap forming plug is pulled out from the cured product of the water-curable composition, the plug is not depressurized. 9 (B), it can be easily extracted. Further, it is particularly preferable that a tube (not shown) is connected to the protruding end 7 of the through hole 6 to positively feed air, so that the plug can be easily removed. Is not particularly limited pressure for feeding the air required for extracting the plug member is preferably less than 150 kg / cm ^2, particularly preferably less than 3 kg / cm ^2. 15 pressure
If the pressure exceeds 0 kg / cm ² , ordinary gas cylinders and small compressors are not sufficient, and special devices for feeding air are required.

When the plug is pulled out from the cured product of the water-curable composition, the withdrawal force per unit contact surface area of the plug (the contact area with the cured product of the water-curable composition) is 0.
It is preferably less than 1 t / m ² . The pulling force is 0.1t /
If it is more than m ² , special drawing equipment may be required.

The method of embedding or setting the void forming material in soil or a hydraulic composition is not particularly limited.

The void forming material is preferably placed in advance in a drill hole or a mold, and then the soil or the hydraulic composition is preferably placed in the mold, but the soil or the hydraulic composition is preferably placed in the mold. After that, the space forming material may be embedded or installed.

The gap forming material to be embedded or installed may be used not only by itself but also by contacting a plurality of plugs. In particular, when the scale of the gap forming material is difficult to handle, it is preferable to divide and embed the gap forming material into a plurality of small scales because the work is easier (see FIGS. 7 and 8).

The void-forming material of the present invention is a material for forming voids in a cured product of a ground, concrete composition, or a water-curable composition such as water glass. In addition, as a method of forming a void, as described above, a plug covered with a water-absorbent sheet is placed in a water-curable composition, and the water-curable composition loses fluidity, or the plug after curing. This is a method of removing air bubbles, and a void can be easily formed.

[0059]

Next, the present invention will be described in more detail with reference to examples.

Example 1 An aqueous monomer solution consisting of 70 mol% of acrylamide and 30 mol% of sodium acrylate (monomer concentration 35
% By weight), N, N-methylenebisacrylamide 0.
1 mol% (relative to monomer), 1 g / mol of 2,2'-azobis (2-amidinopropane) dihydrochloride (relative to monomer) and 1.5% by weight of hydroxyethylcellulose (relative to monomer) are added. The dissolved oxygen inside was removed. A nonwoven fabric made of polyester having a basis weight of 60 g / m ² was immersed in the aqueous monomer solution, and impregnated with the aqueous solution. When this impregnated product was heated and radical polymerization was performed, 80
A water-absorbent sheet was obtained in which g / m ² of the water-absorbent polymer was directly adhered to the sheet-like substrate. This water-absorbent sheet was immersed in cement breathing water for 24 hours, then subjected to suction filtration, the weight of the sheet after filtration was determined and divided by the weight before immersion to determine the water absorption ratio. As a result, the water absorption ratio was 9 times.

Next, as shown in FIGS.
The water-absorbent sheet 2 of 14 mm × 1225 mm was folded in two, and the joined portion was sewn on a sewing machine with a 10-mm seam allowance and a 8-mm wide string. In addition, a string 8 having a width of 8 mm was overlapped on the fold, and sewing was performed by sewing. In this way, the opening diameter is 380 mm (opening circumference 1194 mm),
A water-absorbent sheet bag 2 to which two strings 8 each having a length of 1215 mm were attached was produced.

Next, a foamed polystyrene diameter of 370 m
m, 935 mm long cylinder, inner diameter 1 from top to bottom
A through-hole (air hole) 6 was provided by penetrating a 5 mm hard vinyl chloride resin pipe 7. Next, a 0.1 mm thick polyethylene film (not shown) having a slippery property was covered and fixed so as not to block the mouths of the pipe pipes at the top and bottom of the cylindrical body, thereby producing a plug 1 for forming a void. .

Next, the plug 1 for forming a void was inserted into the water-absorbent sheet bag 2 to obtain a void-forming material 3 wrapped and covered with the water-absorbent sheet as the water-absorbent sheet 2. After filling the void-forming material 3 covered with this water-absorbent sheet into a 200-liter drum, a water-curable mortar composition in which the weight ratio of river sand, cement, and water is 2: 1: 0.65, respectively. Things were injected.

One week later, when air was introduced at a pressure of 1 kg / cm ² from the through hole 6 of the plug 1 for forming a void, the plug 1 for forming a void was extruded above the drum can and easily formed into a cured mortar. Voids (holes) could be formed.
The water-absorbent sheet bag 2 adhered to the inner wall of the formed void (hole), but could be easily removed by pulling the string attached to the bag. Furthermore, the removed void-forming plug 1 was hardly damaged and could be reused. Therefore, the plug 1 for forming a void did not need to be treated as a waste material.

Example 2 A container made of a vinyl chloride resin having an opening diameter of 370 mm and a height of 935 mm having a through-hole 6 having a hole diameter of 15 mm at the bottom of the container, which is not covered with a polyethylene film and has a surface slippery in the container itself, is provided with a gap The plug 1 was formed. Example 1 was carried out under the same conditions as in Example 1 except that the plug 1 was used instead of the plug for forming voids in a column made of expanded polystyrene of Example 1.

One week later, when air was introduced at a pressure of 1 kg / cm ² from the through hole of the gap forming plug 1, the gap forming plug 1 was pushed out above the drum can, and was easily formed in the cured mortar. Hole) could be formed. The water absorbent sheet bag 2 adhered to the inner wall of the formed void (hole), but could be easily removed by pulling the string 8 attached to the bag. Furthermore, the removed void-forming plug 1 was hardly damaged and could be reused. Therefore, the plug 1 for forming a void did not need to be treated as a waste material.

Comparative Example 1 A powdery water-absorbing polymer was made of expanded polystyrene having a diameter of 3
An acrylic binder was applied to the surface of a cylindrical body having a length of 70 mm and a length of 935 mm. The coating film on this surface was peeled off, immersed in cement breathing water for 24 hours, suction-filtered, and the sheet weight after filtration was calculated by dividing by the weight before immersion to determine the water absorption ratio. The water absorption ratio was 2.5 times. It was low.

Next, the cylindrical body is moved from the upper part to the lower part with an inner diameter of 1.
A comparative plug 1 was produced by providing a through hole by penetrating a 5 mm hard vinyl chloride resin pipe.

Next, after filling the comparative stopper 1 into a 200-liter drum, a water-curable mortar composition having a weight ratio of river sand, cement and water of 2: 1: 0.65 respectively was added to the drum. Was injected.

One week later, 1 kg was passed through the through hole of the comparative plug 1.
Although air was blown in at a pressure of / cm ² , the comparative plug 1 could not be pushed out above the drum. Further, the wedge was driven in and attempted to be pulled out, but the comparative plug 1 could only be cracked and could not be removed at once. For this reason, it was unavoidable to remove the file, but it was time-consuming, troublesome, and complicated. Therefore, the comparative plug 1 could not be reused and had to be disposed of as waste material.

Comparative Example 2 A 370 m diameter was used instead of the expanded polystyrene cylinder.
The procedure was performed under the same conditions as in Comparative Example 1 except that an iron cylinder having a length of 935 mm was used.

One week later, the comparative stopper 2 was pulled out above the drum with a force of 0.3 tf. However, the comparative stopper 2 could not be pulled out, and it took time and trouble to perform the filet operation.
It was quite complicated. Further, the comparative plug 2 could not be reused and had to be disposed of as waste material.

Example 3 An inner diameter of 202 mm, a thickness of 6.5 mm and a length of 1000 m
m PVC pipe 10 (VU200)
A 5 mm thick rigid vinyl chloride flat plate was welded to both ends, and an outer diameter of 15 mm and an inner diameter of 10 m
The hard vinyl chloride resin pipe 11 (named VP10) was welded as shown in FIG. As shown in FIG. 10 (B), a water-absorbent sheet bag 13 having a width of 350 mm and a length of 1250 mm obtained by sewing the same water-absorbent sheet as in Example 1 was placed in the above-mentioned vinyl chloride resin container (a plug for forming a void). ) To form a void forming material 14. FIG.
As shown in (C), the gap forming material 14 is fixed vertically so that it does not float in the reinforced concrete formwork.
210-8-20N ready-mixed concrete 15 manufactured at an IS-designated factory was poured to the upper end. After curing for 10 days, compressed air of 1.0 kg / cm ² was introduced from the air inlet (through-hole), and the inner container made of vinyl chloride resin was easily extruded. Further, the water absorbent sheet bag 13 could be easily removed. Furthermore, the extruded container made of vinyl chloride resin could be reused without any damage.

The formed gap can be used as a high-quality buried hole when burying a metal pillar or the like without damaging the reinforcing steel bar 16 or concrete because no scoring work such as core removal is performed.

Example 4 Inner diameter 154 mm, wall thickness 5.1 mm and length 800 mm
A handle 17 as shown in FIG. 11A was attached to one end of the hard vinyl chloride resin pipe 10 (namely, VU150). As shown in FIG. 12 (B), the same water-absorbent sheet as in Example 1 was sewn to obtain a width of 270 mm and a length of 780 m.
m of the water-absorbent sheet bag 13 was coated on the above-mentioned vinyl chloride resin pipe (gap forming plug) to obtain a gap forming material 14.
As shown in FIG. 12 (C), the gap forming material 14 is fixed vertically so as not to float in the reinforced concrete formwork 18 and 210-8-2 manufactured at a JIS designated factory.
0N ready-mixed concrete 600mm from the bottom of the void forming material
Was buried up to the height of After 7 days of curing,
When the handle was pulled and pulled out, the pipe made of the vinyl chloride resin was easily pulled out. Further, the water absorbent sheet bag 13 could be easily removed. Furthermore, the pulled-out polyvinyl chloride resin pipe could be reused without any damage.

The formed voids can be used as high-quality buried holes when metal pillars or the like are buried without damaging the reinforcing steel bars or concrete because no scoring work such as coring is performed.

[0077]

According to the present invention, the water-absorbent sheet swollen with water is interposed between the plug for forming a void and the cured product of the water-curable composition. As a result, the edge can be cut off at the interface between them, and the adhesion can be prevented. In particular, when extracting the plug for forming a void, the thick gel layer formed by swelling of the water-absorbent sheet exhibits lubrication and peeling effects, and the plug can be extracted very easily. In addition, since the void forming plug is easily extracted and can be reused without any damage, the amount of waste material can be significantly reduced.

Examples of the method of coating the water-absorbent sheet with the plug for forming a void include a method of wrapping, affixing with a bonding agent, and striking with a pin-shaped material. A method of wrapping is preferable from the viewpoint of reusing the plug for void formation and water swellability. Make a bag of water-absorbent sheet in advance,
It is particularly preferred in terms of work to put a plug in the bag.

The method of absorbing water in the water-absorbent sheet is a method of absorbing water and swelling with pure water before coating, a method of supplying water after coating, and a method of injecting water into groundwater or a wellbore. And a method of absorbing the water content of a water-curable composition such as cement milk. From the viewpoint of workability, a method of absorbing the moisture of the water-curable composition injected is preferable.

Therefore, the pores can be easily formed by using the pore forming material of the present invention. Also,
By forming a plurality of gaps continuously or intermittently, an arbitrary groove can be formed over a long distance, and a groove for vibration isolation and various water channels such as a railway and a road can be constructed. In addition, the gap forming material of the present invention is installed at the pile head of the cast-in-place concrete pile, and the plug is removed, thereby making it possible to easily break the concrete at the pile head pile.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a gap forming material according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a cross-sectional view similar to FIG. 2, showing another embodiment of the void forming material according to the present invention.

FIG. 4 is a cross-sectional view similar to FIG. 2, showing still another embodiment of the gap forming material according to the present invention.

FIG. 5 is a sectional view similar to FIG. 2, showing another embodiment of the void forming material according to the present invention.

FIG. 6 is a sectional view similar to FIG. 2, showing still another embodiment of the void forming material according to the present invention.

FIG. 7 is a perspective view showing another embodiment of the void forming material according to the present invention.

FIG. 8 is a perspective view showing a state where the gap forming material shown in FIG. 5 is used in combination.

FIG. 9 is a cross-sectional view showing a use state of the gap forming material according to the present invention, wherein (A) shows a state where the gap forming material is filled, and (B) shows a state after removing the gap forming plug. Show.

FIG. 10 is a sectional view showing a use state of the gap forming material according to the present invention, wherein (A) is a plug for forming a gap, and (B) is a plug.
The water-absorbent sheet (C) shows the filling state of the void forming material.

FIG. 11 is a cross-sectional view showing a use state of the gap forming material according to the present invention, wherein (A) is a plug for forming a gap, and (B) is a plug.
The void forming material, (C), shows the filling state of the void forming material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Plug for void formation, 2 ... Water absorption sheet, 3 ... Material for void formation, 6 ... Through-hole.

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[Procedure amendment]

[Submission date] January 21, 1997

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6

FIG. 7

FIG. 8

FIG. 9

FIG. 10

FIG. 11

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoyuki Shirane 4-1-1 Komyobashi, Chuo-ku, Osaka-shi, Osaka Inside Nippon Shokubai Co., Ltd. (72) Inventor Yoshihiro Ikeda 1575 Mizue, Kurashiki-shi, Okayama Pref. In-house (72) Inventor Isao Yanagisawa 18-22 Yotsuyanagi, Maruoka-machi, Sakai-gun, Fukui Prefecture Inside Hokuriku Fine Chemical Co., Ltd.

Claims (3)

[Claims] 1. A material for forming a space for installing a structure, wherein at least a part of the plug for forming a space is covered with a water-absorbent sheet. 2. The void-forming material according to claim 1, wherein the water-absorbent sheet is obtained by polymerizing a polymerization component containing a water-soluble unsaturated monomer on a substrate. 3. The gap forming material according to claim 1, wherein the gap forming plug has at least one through-hole formed so as to communicate with both end faces substantially in the axial direction.