JP2986472B1 - Concrete waterproofing tools - Google Patents

Abstract

An object of the present invention is to provide a concrete water-stopping tool which adheres well to places where the roughness of the latence is severe, and which is immersed in rainwater or its accumulated water but does not have a risk of a water-stopping agent flowing out. Kind Code: A1 Abstract: A knitting yarn for suppressing expansion of a synthetic fiber which is tubularly knitted in a seamless tube form from synthetic fibers which can be dissolved by receiving strong alkaline water of concrete and which cannot be dissolved by the alkaline water, along a longitudinal direction thereof. A waterproofing agent (10) composed of bentonite, sepiolite, and other clay-dried particles or powders, which becomes a water-absorbing gel, was sealed in the inside of the wrapper (11) into which the 12) was knitted and integrated almost completely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete waterproofing tool.

[0002]

2. Description of the Related Art Japanese Patent Application No. 7-115662 proposes a water-stopping device for closing a boundary between a separator of a concrete molding form and its cast concrete and a joint between concrete and the like. This is considered to be the closest approximation to the present invention.

In the prior invention, a water-stopping agent (21) (3) of a highly water-absorbing compound is used as a water-stopping tool for a concrete joint.
1) using an elongated bag of synthetic resin film (20) (30)
4 and 5, and a capsule form in which the same water-stopping agent (11) as a water-stopping tool of the separator (4) is air-tightly filled in a synthetic resin container (10) (FIG. 1, FIG. 2) and the bag (2
0) Both (30) and the container (10) are made of a synthetic resin material that can be decomposed under alkaline conditions.

[0004]

However, regarding the above-mentioned water-stopping device in the form of a string, the elongated bag (20) (3) is required.
Even if 0) is made of a synthetic resin material such as an aliphatic polyester that is hydrolyzed by provisional alkaline water, the above-mentioned bags (20) and (30) are films because of the structural requirements that are limited to such a conceptual description. In addition to the fact that the filling ratio of the waterproofing agents (21) and (31) is not specified in the correlation with this, the bags (20) and (30)
When the water-stopping agents (21) and (31) are filled in a full state, it is difficult to freely bend and deform. Particularly, the waterproofing agent (31) is added to the mesh sheet (32) and the bag (3).
Due to 0), it is impossible to flexibly deform the water-stopping tool having high rigidity (see FIG. 5) which is double-coated.

For this reason, for example, H embedded in concrete
When used in places where the curved surface of the mold steel or other irregularities of the latence are severe, the bags (20) and (30) cannot be adhered well to these places unless they are softened by flooding. May be broken.

[0006] If the bags (20) and (30) are torn, they will be left for a long time at the construction site until the placement of the retrofitting concrete, and during that time, if they are subjected to rainfall or immersed in accumulated water, The water-stopping agents (21) and (31) are swollen and gelled as soon as possible, and are washed away from places where water-stopping is required, which impairs the degree of adhesion to the concrete surface. I have to do it again.

[0007] The bags (20) and (30) are also damaged when the workers at the site are repeatedly stepped on during installation and use, or when a building material such as steel strikes the bag. In any case, the water stopping effect largely depends on the construction place, construction time, weather conditions and the like.

On the other hand, regarding the water-stopping device in the form of a capsule, since the synthetic resin container (10) is a solid product, it may be damaged when bundled for transportation or storage. Is filled with a water blocking agent (11) in a state of directly touching the separator (4).
It is also difficult to pass this quickly through the separator (4), which means that the container (10) and its lid (10)
Even if the cut (10a) is provided in 1), it will not be solved, but it will be a task of heavy labor.

In order to facilitate the penetration into the separator (4), the filling amount of the waterproofing agent (11) must be reduced, so that the boundary between the separator (4) and the cast concrete is reduced. It is impossible to stop water without shortage, and there is a problem that the stability and reliability of the water stopping effect are also poor.

[0010]

DISCLOSURE OF THE INVENTION The present invention is intended to improve such problems, and as a water-stopping tool for concrete which is useful for this purpose, a seamless fiber made of synthetic fiber which can be dissolved in strong alkaline water of concrete. Tubular knitted in a tubular shape, and into the inside of a wrapper in which the knitting yarn for suppressing the expansion of synthetic fibers that cannot be dissolved by the alkaline water is knitted and integrated along the longitudinal direction, bentonite or sepiolite that becomes a water-absorbing gel, The present invention is characterized in that a water-blocking agent made of other clay-like dry particles or powder is sealed in a substantially full state.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a concrete joint according to a first embodiment of the present invention; FIG. However, the water-stopping device (A) reacts the water-absorbing gelled clay-like dry particles or powdered water-stopping agent (10) with strong alkaline water of concrete without reacting to fresh water such as rainwater or tap water. Thus, it is sealed almost completely in the inside of a wrapper (11) made of a circular knitted fabric of synthetic fibers which can be dissolved thereby.

[0012] The water stopping agent (1)
As 0), bentonite or sepiolite may be used alone or separately, or the ratio of bentonite to sepiolite may be from about 50:50 to about 70:30.
Use under mixing.

The physical properties and chemical analysis values of the bentonite used are as shown in Tables 1 and 2 below. According to this, since water absorbs and swells and gels, the water channel is surely closed and stable. A water stopping effect can be achieved.

[0014]

[Table 1]

[0015]

[Table 2]

The physical properties and chemical analysis values of sepiolite (for example, trade name “Aid Plus” of Mizusawa Chemical Industry Co., Ltd.) are as shown in Tables 3 and 4 below.
If it is used as 0), not only fresh water and rainwater absorbed by the bentonite but also its three-dimensional chain-like tunnel structure (crystal structure) absorbs and gelates seawater (salt) and oil, etc. In addition, it has a dry consolidation property, and can also close waterways, and is useful as a waterstopping agent (10) for use in landfills, especially at seaside.

[0017]

[Table 3]

[0018]

[Table 4]

On the other hand, as synthetic fibers used for the material of the wrapper (11), biodegradable polylactic acid fibers which are not dissolved by neutral water of PH7 but are dissolved by strong alkaline water of PH11 or more. (For example, the product name “Lactron” of Kanebo Synthetic Fiber Co., Ltd.), heat-fusible polylactic acid fiber obtained by blending a natural polymer polysaccharide and a plasticizer with starch as a main component is preferable.

The knitting yarn of the biodegradable synthetic fiber is knitted in a tubular manner (warp knitting or knitting) to finish a wrapping bag (11) in a seamless tube form. That is, for example, by using a 75 denier knitting yarn in which about 24 long fibers of about 3.125 deniers are alternately twisted in the left and right direction and rotated while heating appropriately, the fibers are not twisted in one direction, and A bulky and stretchy wrapper (1
It is created as 1).

The knitting state of the wrapper (11) is as suggested in FIG. 3. Since the knitting yarn of Z twist and S twist is structured so as not to generate twisting habit, it is dried. The water-stopping agent (10) in the state can also be filled in very easily.

However, in the tubular knitting process of the wrapper (11), a knitting yarn (12) of polyethylene, nylon, vinylon, or other synthetic fiber insoluble in alkaline water is transferred to the circumference of the wrapper (11). The braid is integrated along the longitudinal direction of the radially symmetric distribution position that divides the surface substantially equally. The reason is as follows.

That is, after the water-stopping tool (A) of the present invention is installed at a concrete splicing portion or the like, the cleaning surface of the concrete surface called water curing is artificially received, or the construction site is extended for a long time by extending the construction period. In the case where the water-stopping agent (10) is repeatedly subjected to rainfall or immersed in the accumulated water during standing, the water-absorbing water-stopping agent (10) swells and gels to form a cohesive mass, and the zipper (11) is accordingly formed. The result is expansion before placing the retrofitting concrete. At this time, the wrapper (11) does not react to the fresh water such as the cleaning water or the rainwater, and of course, does not dissolve even if it receives them.

The wrapper (11) is made of a circular knitted fabric. Since the loop of the knitting yarn forming the wrapper (11) freely deforms and is rich in elasticity and flexibility, the wrapping bag (11) is made before the concrete is cast. If unrestricted expansion is allowed, excessive expansion along the longitudinal direction will not hinder, but excessive expansion in the radial direction will turn the water-stopping tool (A) into excessive foreign matter (impurities) to be embedded in concrete. In addition to giving a feeling of resistance to the concrete, the swelling and gelation of the water-stopping agent (10) ends before the concrete is put into place and the swelling action does not accumulate. The swelling effect in response to the moisture penetrating into the seam with the concrete is no longer exhibited, and the secondary water stopping effect of completely closing the seam may not be achieved.

For this purpose, the knitting yarn (12) of the synthetic fiber which is insoluble in the alkaline water is knitted and integrated, and the knitting yarn (12) suppresses the excessive expansion of the wrapper (11) and encloses therein. The water-stopping agent (10) thus kept is kept in a state of accumulation of swelling action. Such a knitting yarn for suppressing expansion (1)
Even if we knit and integrate 2), the wrapper (11)
Can be freely bent and deformed without loss of flexibility.

As is apparent from FIGS. 1 and 2, the expansion suppressing knitting yarn (12) is arranged along the longitudinal direction at a radially symmetric position that divides the circumferential surface of the wrapper (11) into approximately four equal parts. Preferably, the inflation limit of the wrapper (11) is set to about 1.5 times. By knitting the knitting yarn (12), it is possible to mechanically knit the wrapper (11) mechanically from the synthetic fiber very easily and smoothly.

Although the stitches of the wrapper (11) are of course finer than the particles or powder of the waterproofing agent (10), the wrapped wrapper (11) is poured into hot water of about 100 ° C. The stitch is heat shrunk more finely by a method such as passing through, and the wrapper (11) expands in response to the swelling and gelation of the water stopping agent (10).
It is desirable to determine so as not to leak out.

In any case, the wrapper (11) knitted as shown in FIG. 3 is cut into a length (L) of about 2 to 5 m, and is cut in the longitudinal direction of the wrapper (11). One end (13a) of the opening is sealed first, and then the other end (13a) of the remaining opening is sealed.
b) water-stopping agent of the above clay-like dry particles or powder (10)
Is filled almost completely (about 90% or more), and the other end (13b) of the opening is finally sealed.

It is preferable that the diameter (D) of the product-water-stopping device (A) in a state where the water-stopping agent (10) is sealed in the wrapper (11) is set to about 10 to 20 mm. If it is thinner than about 10 mm, the temporary water-stopping agent (10) becomes thicker due to swelling gelation, but there is a concern that the water-stopping effect may still be insufficient. ) Due to the swelling effect,
This is because, as an excessive foreign substance (impurity) to be embedded in concrete, it gives a sense of resistance to its use. In this regard, the expansion limit along the radial direction of the wrapper (11) is set to about 1.5 times by the weaving of the expansion suppressing knitting yarn (12) before placing the retrofitting concrete. Is as described above.

The reason why the water-stopping agent (10) is almost completely filled in the wrapper (11) is that the water-stopper (10) in a dry state is freely positioned in the wrapper (11). This is for preventing the water from moving and causing the water stopping tool (A) to partially change in diameter (D) like a snake swallowing an egg. It can be said that the fact that the knitting yarn (12) for suppressing the expansion of the wrapper (11) is knitted and integrated into this also works organically.

The length (L) of the wrapper (11) is about 2
The reason why it is cut to 5 m is to allow it to be used as a water-stopping tool (A) such as a concrete splicing part in the greatest common denominator or for general use, and its length (L) is shorter than about 2 m. Must be used frequently,
On the other hand, if it is longer than about 5 m, one worker cannot conveniently handle and carry on the construction site.

As a means for sealing the wrapper (11), a separate fixing device (14) such as a tying strap, a clasp, or an adhesive can be used in addition to the heat sealing. The method of filling the water wrapping agent (10) into the wrapping bag (11) can be freely selected. However, based on light particles or powder in a dry state, the wrapping bag (11) is wrapped by wind power such as a blower. It can be said that blowing into the bag (11) is effective for mass production.

As shown in FIGS. 1 and 2, the water-stopping tool (A) of the present invention is a wrapper (11) made of a circular knitted fabric having high elasticity and flexibility.
Is filled with a water-blocking agent (10) of dry clay particles or powder. By freely bending and deforming the water-blocking agent (10), for example, the bent surface of H-shaped steel embedded in concrete, The water-stopping device (A) can be installed and used in a familiar and close contact state so as to follow a place where the irregularity of the latencies is severe, and it can be repeatedly trampled in the installed and used state but does not break. .

[0034] In this respect, even though it is composed of synthetic fibers which can be dissolved by receiving strong alkaline water, the warp and the weft are interlaced in a binding state in the wrapping as a woven fabric, so that the elasticity and the flexibility are increased. In particular, when the water-stopping agent is filled in the inside of such a wrapper in a full state, the water-stopping agent is still in a state of a solid rod even though the water-stopping agent is still a dry particle or a powder. It cannot be freely bent and deformed, and may be broken. This is true even when the waterproofing agent is surrounded by a coating film or a plastic film instead of the woven fabric.

In the case of a wrapper made of a non-woven fabric of the same synthetic fiber, it is difficult to finish the thickness and strength of the wrapper uniformly, so that the wrapper is forcibly bent and deformed or repeatedly trampled at a location with severe unevenness. If it does, it will rupture from the thin and weak part, and it is inevitable that the waterproofing agent will leak out.

Next, FIGS. 4 and 5 show a second embodiment of the present invention suitable for stopping water at the boundary between the separator (15) of the concrete molding form (M) and the cast concrete (C).
According to the embodiment, in this embodiment, the water-stopping tool (A) of the first embodiment is wound into a donut shape that can be inserted into the separator (15).

In other words, the water-stopping device (B) of the second embodiment has a structure in which the water-stopping device (B) is formed into a seamless tubing (11) from the biodegradable synthetic fiber into a seamless tube. After filling the agent (10) almost completely, the one end (13a) of the wrapper (11) and the other end (13b) of the opening are abutted or overlapped with each other to perform heat sealing or bonding. By fixing and integrating through a means, a donut form in which the center is opened as a through-hole (16) to the separator (15) is exhibited.

In this case, the diameter (S) of the through hole (16) is the same as the diameter of the separator (15) or a diameter smaller than that of the wrapper (11) by, for example, about 8 mm. , So that it can adhere to the circumferential surface of the separator (15).

Also in the second embodiment, since the wrapper (11) of the water-stopping tool (B) is also made of a circular knitted fabric having high elasticity, the separator (15) of the concrete molding form (M) is used. ) Can be used easily and lightly and can be used. Also, there is no danger of breakage during transporting or storage as well as during the work.

In using the water-stopping tool (A) of the first embodiment, as is apparent from various examples of use in FIGS. 6 to 9, the water-stopping tool (A) is connected to a joint between concrete (C1) and (C2). Along with the reinforcing steel (17) of the existing concrete (C1) with a binding wire (18) and the like. In order to prevent the tool (A) from floating or shifting, the tool (A) is stably sandwiched between the joint (P) between the existing concrete (C1) and the retrofit concrete (C2).

When the joints of the concretes (C1) and (C2) form a vertical surface or a ceiling surface as shown in FIGS. 7 to 9, binding of the water-stopping tool (A) to the reinforcing reinforcing bar (17), etc. In addition, the spindle stud (19) is fixedly installed on the vertical surface or the ceiling surface, and the spindle stud (1) is fixed.
The water-stopping tool (A) is bound to the needle of 9), pressed against a vertical surface or a ceiling surface by a separate saddle band (20), or stuck with an adhesive to form the water-stopping tool (A). A) is positioned and fixed stably.

If the length (L) of the water-stopping tool (A) is insufficient when the water-stopping tool (A) is installed and used, the water-stopping tool (A) is added to the water-stopping tool (A), and a plurality of adjacent added portions (X) are connected with a binding wire. It is fixed by a fastener, a hook-and-loop fastener, a hook-and-loop fastener (so-called Velcro fastener or Velcro fastener), or other suitable fasteners (21).

In any case, if the water-stopping tool (A) is fixedly installed at the joint between the concretes (C1) and (C2) as described above, water is poured before the post-installation concrete (C2) is poured. Then, the water stopping agent (1) of the water stopping tool (A)
0), and is kept in a state where primary water can be stopped by the action of swelling and gelation.

If the water-stopping agent (10) is swollen and gelled by relying only on the water contained in the concrete (C2) to be cast, the water originally required for hardening of the concrete (C2) is taken away. Therefore, the above-mentioned flooding is called as water curing and is given as cleaning water for the existing concrete (C1) because it has a bad influence on its hardening.

However, the water-stopping tool (A) is repeatedly subjected to rainfall or immersed in the accumulated water until the post-installation concrete (C2) is poured, and the water-stopping agent (10) is absorbed by the water absorption. ) Swells and gels to achieve the primary water-stop state, the above artificial watering is not necessarily required.

Then, the retrofitting concrete (C
When 2) is cast, the concrete (C2)
After 3 days, the concrete (C
Water may permeate through the joint (P) with 1), but the wrapper (11) that has received the strong alkaline water of the concrete (C2) begins to dissolve over time and disappears after about one week. As a result, the water-stopping agent (10) in the course of the swelling gelation is in a so-called bare state, is about 20 times or more larger than the initial dry particles or powder state, and swells freely, and the existing The joint (P) between the concrete (C1) and the retrofit concrete (C2) is shown in FIG.
As in the case of 1, the entirety is closed, and a reliable secondary water stopping effect can be achieved.

Since the wrapper (11) of the water-stopping tool (A) is made of a circular knitted fabric having high elasticity and flexibility, the H-shaped steel (22) embedded in concrete as shown in FIG. 12 is bent. It can be freely wrapped around the surface and can be used, and it can follow even places with severe irregularities and adheres well, so it is almost completely filled inside the wrapper (11). Together with the water-stopping agent (10) provided, a complete water-stopping effect can be achieved.

Incidentally, the wrapper (11) was not completely dissolved due to lack of strong alkaline water, and the concrete (C)
1) Even if it remains in (C2), the wrapper (11) is composed of biodegradable synthetic fibers, and is eventually decomposed into carbon dioxide and water by the action of bacteria and microorganisms. Disappears after about one to two months.

On the other hand, the water stopping tool (B) of the second embodiment
In the case of using a water-stopping tool (B), the water-stopping tool (B) may be inserted into the separator (15) as shown in FIGS.

[0050] Then, the strong alkali water of the concrete (C) poured into the form (M) also dissolves the wrapper (11) of the water-stopping tool (B) with time, and The water-stopping agent (10) that has absorbed the water turns into a swelling gel, closing the boundary between the separator (15) and the cast concrete (C) to complete the water-stopping action. Reference numeral (23) in FIG. 13 denotes a pair of opposing dam plates forming the form (M), (24) denotes a form tie fastened to both ends of the separator (15), and (25) denotes a cone. I have.

In particular, when a concrete structure is to be constructed in a seaside landfill, as the water-stopping agent (10) of the water-stopping tools (A) and (B) according to the present invention, sepiolite instead of the bentonite is used. Which is also filled in the inside of the wrapper (11) in a full state.

In this case, since the sepiolite of the water-stopping agent (10) absorbs seawater (salt) and oil to form a gel and exhibits a large swelling action and has a dry consolidation property, the first and second embodiments are described. Concrete (C1) (C
Starting from the joint in 2), the concrete molding form (M)
Separator (15) and its cast concrete (C)
In addition, the water can be reliably stopped at the boundary with the water, and the deodorizing effect can be expected. In addition, depending on the construction site of the concrete structure, as the water stopping agent (10) in which the bentonite and sepiolite are mixed,
The fact that it may be used is as described above.

[0053]

As described above, the concrete waterproofing tools (A) and (B) according to the present invention are knitted in a seamless tube form from synthetic fibers which can be dissolved by receiving strong alkaline water of concrete. In addition, bentonite, sepiolite, and other water-absorbing gels are formed along the longitudinal direction of the wrapper (11) into which the knitting yarn (12) for suppressing the expansion of synthetic fibers that cannot be dissolved by the alkaline water is knitted and integrated. Waterproofing agent consisting of dry clay particles or powder (10)
Is almost completely filled, so that the problems of the prior art described at the beginning can be completely improved.

That is, according to the above-described structure of the present invention, the wrapper (11) of the water-stopping tools (A) and (B) is made of a synthetic fiber which can be dissolved by receiving strong alkaline water of concrete to form a seamless tube. It is knitted in a tube and is rich in elasticity and flexibility. Moreover, the waterproofing agent (10) enclosed in this is
Since it is a clay-like dry particle or powder such as bentonite or sepiolite, it can be freely and flexibly deformed freely even if it is almost completely filled inside the wrapper (11).

As a result, the water-stopping device (A) is designed to follow not only places where the latence of the concrete is extremely uneven, but also curved surfaces of H-shaped steel embedded in the concrete. (B) can always be installed and used in a stable close contact state, and there is no need to perform a special ground leveling operation on the concrete surface.

The wrapper (11) is made of a circular knitted fabric of synthetic fibers soluble in strong alkaline water of concrete and does not dissolve in fresh water. Until the retrofitting concrete is poured, the water-stopping agent (10) which has received artificial administration of cleaning water, has repeatedly received rainfall, or has been immersed in the pool water has been absorbed. Although it swells and gels, it dissolves the zipper (11) and waterproof agent (10)
There is no danger of water loss, and the primary water stopping effect can be achieved by the water stopping agent (10).

In particular, the wrapper (11) has a knitting yarn (12) for suppressing expansion of synthetic fibers which does not dissolve in alkaline water.
However, since it is knitted and integrated along the longitudinal direction, the wrapper (11) expands excessively in accordance with the swelling and gelation of the waterproofing agent (10) before the placement of the retrofitting concrete. Can be limited by the expansion suppressing knitting yarn (12), which not only gives no resistance to use but also has a swelling effect for the secondary water stop following the water stop agent (10). It is possible to accumulate it.

As a result, when the post-installation concrete is continuously poured, the wrapping bag (1) receives the strong alkaline water.
1) is dissolved, and the water-stopping agent (10) becomes so-called naked, so that it swells freely and further swells, so that seams and the like with the existing concrete can be reliably stopped. A secondary water stopping effect can be achieved.

In particular, if the structure of claim 2 is adopted,
The above effect can be achieved more efficiently, and the mechanical knitting of the wrapper (11) becomes easy. In addition, the wrapper (11) may be placed in the concrete due to, for example, lack of strong alkaline water. Even if the burial remains, there is an effect that it can be completely eliminated by its biodegradability.

According to the third aspect of the present invention, the water stoppage tool (B) is connected to the separator (M) of the concrete molding form (M) by the through-hole (16) opened to the center of the donut shape. 15) into the separator (15) and the cast concrete (C) in a reliable and stable manner. In addition, the convenience of handling at the construction site and carrying is also enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG.

FIG. 3 is a plan view showing a knitted state of the wrapper.

FIG. 4 is a schematic front view showing a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line 5-5 in FIG. 4;

FIG. 6 is a cross-sectional view showing a state in which the water stoppage tool of the first embodiment is installed and used in a concrete splicing portion (plane).

FIG. 7 is a cross-sectional view of a state where the same is installed and used in a concrete joint portion (vertical plane).

FIG. 8 is a cross-sectional view of a state where it is installed and used in a concrete joint portion (right-angled surface).

FIG. 9 is a cross-sectional view showing a state where the same is installed and used in a concrete joint portion (ceiling surface).

FIG. 10 is an enlarged sectional view showing a water stopping state of a concrete splicing portion by the water stopping tool of the first embodiment.

FIG. 11 is a sectional view taken along line 11-11 of FIG. 10;

FIG. 12 is a perspective view of the water-stopping tool according to the first embodiment in a used state in which the water-stopping tool is wound around an H-shaped steel.

FIG. 13 is a cross-sectional view of a used state in which the water stoppage tool of the second embodiment is passed through a separator.

FIG. 14 is an enlarged sectional view taken along line 14-14 of FIG.

[Explanation of symbols]

 (10) Waterproofing agent (11) Clothes wrapper (12) Knitting yarn for suppressing expansion (13a) Opening one end (13b) Opening other end (14) Fixing device (16) (A) · Water stoppage tool (B) · Water stoppage tool (C) · Casting concrete (C1) · Existing concrete (C2) · Retrofit concrete (M) · Concrete formwork (P) · Joint (D) · Diameter (L) · Length

Claims (3)

(57) [Claims] 1. A knitting yarn for suppressing expansion of a synthetic fiber which is cylindrically knitted in a seamless tube form from synthetic fiber which can be dissolved and melted by receiving strong alkaline water of concrete, and which cannot be dissolved by said alkaline water along a longitudinal direction thereof. A water-blocking agent (10) composed of bentonite, sepiolite, or other dry clay particles or powder that becomes a water-absorbing gel was sealed almost completely inside the wrapper (11) into which (12) was knitted and integrated. A water stoppage for concrete, characterized in that: 2. An expansion suppressing knitting yarn (1) is provided at a radially symmetric position where a circumferential surface of a tubular wrapper (11) formed of a biodegradable polylactic acid fiber in a tubular shape as a seamless tube is substantially equally divided into four.
2. The concrete waterproofing tool according to claim 1, wherein 2) is knitted and integrated. 3. A water-blocking agent (10) is filled almost completely into the inside of a wrapper (11) knitted into a seamless tube form, and one end (1) of an opening of the wrapper (11) is filled.
The concrete according to claim 1, characterized in that, by fixing and integrating the opening (3a) and the other end (13b) of the opening, the center is rolled and bent into a donut shape which is opened as a through hole (16). Water stoppage tool.