JPH065122Y2 - Non-woven fabric for water-permeable formwork and water-permeable formwork to which it is attached - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to a water-permeable non-woven fabric for concrete formwork and a non-woven fabric which is attached to the concrete placing side of the concrete formwork to remove water and air from the concrete. The present invention relates to the attached water-permeable formwork.

(Prior art) Recently, attention has been paid to effectively removing water and air separated from concrete by attaching a special sheet material to the formwork for the purpose of aesthetic appearance of concrete surface and improvement of durability of concrete surface. Various types of water-permeable sheets such as non-woven fabrics, porous films, and woven fabrics are used as this type of water-permeable sheet.

Each of these water-permeable sheets is made so that air and excess water can be degassed and dehydrated from the surface, and can be easily demolded from the solidified concrete surface. It is formed to enhance the drainage effect, and its back side is fixed with an adhesive or stapler to firmly fix it to the formwork, and also inside the sheet and from the backside to the formwork to the outside of the permeable sheet. It is designed for easy drainage.

However, the water-permeable sheet as described above usually has to be used several times from the economical point of view, without being stopped once.

Therefore, recently, a sheet material that can withstand such use several times has been studied, and one example thereof was proposed in Japanese Patent Laid-Open No. 63-63858.

As is clear from the description in the above publication, this sheet material has a good releasability for pouring concrete, and a surface layer having a large number of water-permeable and air-permeable pores, and a surface layer provided on the back surface of the surface layer. A large number of water passages and air passages communicating with the pores are provided in the thickness direction, and the structure has a layer-holding base layer that does not buckle or bias the pressure of the cast concrete.

On the other hand, the present applicant also aimed to develop the above-mentioned sheet material using a non-woven fabric as a base material, and further proposed a non-woven fabric for water absorption and drainage which was improved in JP-A-63-282851.

This is a method in which a fiber layer made of synthetic fibers and a synthetic fiber base cloth are integrated by needle punching, and then only the surface of the fiber layer is formed into a fluff-free smooth surface layer by heat processing, and the subsequent fiber layer. And a relatively dense intermediate layer made of a base cloth, and an adhesive backing layer formed by integrating the fibers on the back surface of the base cloth with the base cloth surface by heat treatment. Aeration rate is 2.0-0.5cc / cm ² / se
c, the vertical hydraulic conductivity is 10 ⁻² to 10 ⁻⁴ / sec, and the surface layer portion is a nonwoven fabric having small holes or fiber gaps that do not allow the solid content of the cement paste to permeate.

(Issues to be solved by the device) However, the water permeable sheet was found to be
It was found that if the water absorption performance and drainage performance are different in each part of the sheet, color unevenness occurs on the concrete surface.

That is, the surface that has sufficiently absorbed excess water becomes dark (this is also the effect of the water-permeable mold), and the insufficient water absorption surface becomes whitish.

The dark areas are dense and have a high surface strength, while the whitish areas are not so dense, and are slightly porous and have a low surface strength.

This will be described in more detail. For example, in FIGS.
Shown below is an example of a water-permeable formwork in which a non-woven fabric (2) of about 2 mm is attached to a formwork (1) with a thickness of several cm. In these figures, the water absorbed from the concrete side (3) is the non-woven fabric (2). Inside, the vertical direction perpendicular to the figure, the horizontal direction shown in the figure, and the formwork (1)
It flows through between and is discharged to the outside.

However, a nonwoven fabric generally has a horizontal hydraulic conductivity (1 × 10 °) one digit higher than a vertical hydraulic conductivity (1 × 10 ⁻¹ ). Especially in the case of non-woven fabrics for water permeable form, the vertical permeability coefficient is set to a small value of 10 ^-3 to 10 ^-4 in order to break the rapid water absorption from the concrete surface. The amount of water absorbed from the concrete surface is larger at the side edges than at the center of the frame.

Therefore, as described above, the central portion becomes whitish and the side edge portions become blackish, resulting in uneven color.

The present invention aims to deal with the above-mentioned situation and to prevent the above-mentioned color unevenness and improve the aesthetic appearance of the concrete surface by eliminating the drainage from the end face.

(Means for Solving the Problems) That is, one of the features of the present invention that achieves the above-mentioned object is that one of them has a required size, has a good releasability for pouring concrete, and has a large number of fibers between constituent fibers. The point is that the end faces of both side edge portions of the non-woven fabric for water permeable form having the water passage and ventilation gaps are sealed so that the suction and drainage from the end faces of both side edge portions cannot be performed.

Further, the invention according to claim 2 is one in which the above characteristics are further embodied. The non-woven fabric for formwork proposed by the present applicant, that is, a fiber layer made of synthetic fibers and a synthetic fiber base cloth are needle punched. End face of both sides of a non-woven fabric of a required size constituted by three layers, that is, a surface layer that is made into a smooth porous structure and an intermediate layer that follows the surface layer and a back layer that has the above-mentioned base cloth by heat melting or caulking. Sealed by use,
The structure is characterized in that it is impossible to absorb and drain water from the end faces of the both side edge portions.

Further, the invention according to claim 3 is characterized in that the non-woven fabric is laminated on a mold to form a water-permeable mold itself.

(Operation) The non-woven fabric for water-permeable formwork of the present invention having the above-mentioned configuration,
It is used by pasting on a water-permeable formwork, when placing concrete inside the formwork, the placed concrete is through a large number of voids in the nonwoven fabric, especially when the surface layer is a smooth porous surface, Water is slowly absorbed through the holes,
This absorbed water is discharged as it is from the back surface of the non-woven fabric by removing the water from the back surface of the non-woven fabric by closing the end faces on both side edges as it is and discharged from the lower end surface of the non-woven fabric by flowing in the vertical direction. Thus, the water absorption and drainage performance on the front surface of the non-woven fabric is averaged to eliminate black and white color unevenness on the concrete surface.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a state in which the non-woven fabric according to the present invention is attached to a form, (1) is the form, (2) is the non-woven fabric, (3) is the concrete side, and the non-woven fabric (2) is The end faces (4) on both side edges are hermetically sealed and bonded to the formwork (1) to form a water-permeable formwork.

Here, the formwork (1) usually has a size of about 90 cm in width and 180 cm in length, and therefore the non-woven fabric (2) also has a size corresponding to this, and its thickness is about 1 to 2 mm. The end faces of both side edges are sealed.

Incidentally, as a means for sealing, when the nonwoven fabric is made of synthetic fiber, it is usually easiest to melt and seal the end face, and in some cases, it is possible to simply seal by performing hot melt cutting. is there.

However, the method is not limited to heat melting, and it is of course possible to use a caulking agent, for example, a rubber-based adhesive, a filler, etc. for sealing, and it is also possible to use other possible means.

In addition, various types of non-woven fabrics are attached to the above-mentioned form, and they have a required size, good releasability from the cast concrete, and a large number of water passages and ventilation gaps between the constituent fibers. Any non-woven fabric can be used, but the non-woven fabric previously proposed by the present applicant, that is, a fiber layer made of synthetic fibers and a synthetic fiber base fabric are integrated by needle punching, and the surface thereof is subjected to heat treatment or the like. A non-woven fabric having a three-layer structure of a surface layer having a smooth porosity, a rough intermediate layer mainly composed of a fiber layer following the surface layer, and a back layer including a base cloth on the back side is most suitable and effective. Is.

Further, in addition to the above-mentioned constitution, a synthetic resin plate having small irregularities forming a continuous drainage passage in the vertical direction is attached to the back side base fabric of the non-woven fabric, or the concrete side of the non-woven fabric is bonded. It is also preferable to provide uneven creases that similarly form a continuous drainage passage in the up-down direction on the water absorption layer located at and the drainage layer located at the drainage side.

Thus, make a form with the above non-woven fabrics attached,
When concrete is placed inside this, drainage from the end face of the non-woven fabric disappears, the horizontal water flow that has been actively occurring in the non-woven fabric is stopped in the non-woven fabric, and only the vertical flow exists in the non-woven fabric, and the concrete surface The effect of absorbing and draining water from is extremely good.

(Effect of the Invention) The present invention is a non-woven fabric that prevents drainage from both end edges by sealing both end edges of the non-woven fabric for permeable form as described above. The horizontal flow is active in the non-woven fabric, and the side edge part absorbs more water from the concrete surface than the center part of the form,
Although the central part was whitish and the side edges were dark and uneven color was generated, the horizontal flow was eliminated by stopping the drainage from the end face, and the water absorbed from the concrete surface was discharged from the back side of the nonwoven fabric. And, it flows up and down inside the nonwoven fabric, and as the water is drained from the lower end surface, the water absorption and drainage on the entire surface of the concrete is averaged to eliminate the occurrence of the color unevenness, and the surface of the concrete is sufficiently absorbed to make the concrete surface dense, and However, there is a remarkable effect that the surface strength can be increased and a good concrete surface can be obtained.

In addition to the above effects, the device according to claim 2 is particularly effective in improving the mold releasability and enhancing the water absorption and drainage efficiency, and the device according to claim 3 is practically applicable as a water-permeable mold. It is a rich formwork.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view in which a non-woven fabric according to the present invention is used and superposed on a mold, and FIGS. 2 and 3 are cross-sectional schematic views showing the flow of water absorption and drainage in a conventional non-woven fabric pasting mold. . (1) …… Formwork, (2) …… Nonwoven fabric, (3) …… Concrete side,

Claims (3)

[Scope of utility model registration request] 1. A non-woven fabric for a water-permeable mold, which has a required size, has good releasability from cast concrete, and has a large number of water passages and ventilation gaps between constituent fibers. A non-woven fabric for a water permeable formwork, characterized in that the end faces of the parts are hermetically sealed so that water cannot be absorbed and drained from the end faces of the side edges. 2. A surface layer in which a fiber layer made of synthetic fibers and a synthetic fiber base cloth are integrated by needle punching, a large number of water passages and ventilation voids are provided between constituent fibers, and the surface is made smooth and porous. The end faces of both side edges of a non-woven fabric of a required size constituted by three layers of an intermediate layer following the surface layer and a backing layer having the above-mentioned base cloth are sealed by heat melting or caulking, and sucked from the end faces of both side edges. Non-woven fabric for permeable formwork, which is characterized by preventing drainage. 3. A water-permeable mold which is formed by laminating a non-woven fabric having a required size on a mold, and has a smooth surface,
Further, a water-permeable formwork characterized in that the end faces of both side edges of a non-woven fabric having a large number of water passages and air passages in the thickness direction are hermetically sealed so that water cannot be absorbed and drained from the end faces.