JP2014195957A - Manufacturing method of fiber-reinforced hydraulic inorganic molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a fiber-reinforced hydraulic hardened body having high strength and designability, by an efficient process in which kneading and extrusion are omitted.SOLUTION: A manufacturing method at least includes: a mixing process in which water, a hydraulic inorganic material, and a hydraulic material that at least includes an alkali resistance fiber are mixed; an input process in which the mixed hydraulic material is input into a mold form without being kneaded; and a pressing process in which the hydraulic material input in the mold form is pressed by a press. In the mixed hydraulic material, a ratio of an amount that passes a mesh having a sieve opening of 20 mmΦ is at least 95 wt.%, and a ratio of an amount that does not pass a mesh having a sieve opening of 3 mmΦ is at least 95 wt.%.

Description

  The present invention relates to a method for producing a fiber-reinforced hydraulic cured body having high strength and design properties in an efficient process in which kneading and extrusion are omitted, and a fiber-reinforced hydraulic inorganic molded body produced by the method. .

  Molded products using hydraulic materials are widely used as construction materials and civil engineering materials such as slate and tile. In order to improve the strength of such a molded product, reinforcing fibers are used.

For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 11-117458), in a thick slate formed by embedding reinforcing fibers in mortar, a lap step portion is provided on a side edge, and the boundary of the wrap step portion is provided. A thick slate having a vertical rib portion in which a reinforcing fiber is embedded is disclosed.
In this document, a mixture of cement, fine aggregate, lightweight aggregate, reinforcing fiber, and the like is used for a back surface molding die in which a reinforcing fiber mixed mortar obtained by adding water and kneading is laminated on a top surface with a water-permeable sheet. After the supply, the upper surface molding die is lowered, and the supplied reinforcing fiber mixed mortar is squeezed to form a thick slate.

  Further, Patent Document 2 (Japanese Patent Laid-Open No. 5-329823) discloses a method for producing a hydraulic inorganic molded body characterized in that a composition comprising a hydraulic inorganic substance and water is extruded and then subjected to vibration press molding. Is disclosed.

  In this document, a mixture of a hydraulic inorganic substance, water and, if necessary, a reinforcing fiber, a water-soluble polymer substance, and an inorganic filler is extruded with an extruder having a screw, and further obtained continuously. It is described that a body is cut, supplied to a vibration press molding die, and molded into a desired shape by vibration press molding to produce a hydraulic inorganic molded body.

Japanese Patent Laid-Open No. 11-117458 JP-A-5-329823

  However, Patent Documents 1 and 2 both require a kneading step for kneading the mixture, and the material cannot be homogenized without the kneading step. Moreover, when performing the extrusion process using an extruder, production speed is slow and efficiency is bad.

An object of the present invention is to provide a hydraulic inorganic material in which the kneading step and the extrusion step are omitted and the production efficiency is improved in a method for producing a hydraulic inorganic molded body usually performed by a mixing step, a kneading step, an extrusion step, and a pressing step. It is providing the manufacturing method of a molded object.
Another object of the present invention is to provide a production method that can easily and uniformly fill a mold having a complicated shape, and can efficiently produce a high-strength and design-reinforced fiber-reinforced hydraulic cured body. It is in.
Still another object of the present invention is to provide a fiber-reinforced hydraulic inorganic molded body obtained by such a production method.

  The inventors of the present invention, as a result of intensive studies to achieve the above object, show that a hydraulic material in a state containing water, a hydraulic inorganic substance, and an alkali-resistant fiber is used even when fibers are used. In a production method comprising a mixing step adjusted to have a specific particle size distribution, the subsequent kneading step and extrusion step are omitted, and the design and strength of the molded product obtained even when this mixture is directly put into a formwork Has been found to be comparable to conventional products, and the present invention has been achieved.

That is, the present invention includes a mixing step of mixing water, a hydraulic inorganic substance, and a hydraulic material containing at least alkali-resistant fibers, and a charging step of charging the mixed hydraulic material into a mold without kneading. And a pressing step of pressing the hydraulic material put into the mold by pressing,
The mixed hydraulic material is a fiber-reinforced water in which the ratio of the amount passing through a mesh having a sieve opening of 20 mmΦ is 95% by weight or more and the ratio of the amount not passing through a mesh having a sieve opening of 3 mmΦ is 95% by weight or more. The present invention relates to a method for producing a hard inorganic molded body.

  The alkali-resistant fiber may be at least one selected from the group consisting of alkali-resistant glass fiber, carbon fiber, polyvinyl alcohol fiber, polyethylene fiber, polypropylene fiber, acrylic fiber, and aramid fiber, and preferably polyvinyl. Alcohol fibers may be used.

  The fiber diameter of the alkali resistant fiber may be, for example, about 2 to 1000 μm, and the aspect ratio may be about 5 to 1000. Moreover, the alkali-resistant fiber may have a fiber strength of 5 cN / dtex or more. The ratio of the alkali resistant fiber to the solid content of the hydraulic material may be, for example, 0.1 to 5% by mass.

  After the charging step, vibration may be applied to the mixture charged into the mold. The vibration may be performed before the pressing step or may be performed during the pressing step.

  Furthermore, the present invention includes a fiber-reinforced hydraulic inorganic molded body produced by such a production method.

According to the present invention, among the mixing step, the kneading step, the extrusion step, and the pressing step, the kneading step and the extrusion step can be omitted and the hydraulic inorganic molded body can be manufactured, so that the production efficiency is greatly improved. be able to.
In addition, even with such a production method with improved production efficiency, it is possible to easily and evenly fill a complex-shaped formwork, and to produce a high-strength and designable fiber-reinforced hydraulic cured body. Can do.

The present invention is a method for producing a fiber-reinforced hydraulic inorganic molded body, wherein the production method comprises mixing a hydraulic material containing at least a hydraulic inorganic substance, water, and alkali-resistant fibers;
A charging step of charging the mixed hydraulic material into the mold without kneading;
A pressing step of pressing the hydraulic material put into the mold with a press;
At least.

(Mixing process)
In the mixing step, a hydraulic material containing at least water, a hydraulic inorganic substance, and an alkali-resistant fiber is mixed.

  Examples of the hydraulic inorganic substance include cement and gypsum. Examples of the cement include ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, medium-heated Portland cement such as Portland cement, alumina cement, and blast furnace cement. , Silica cement and fly ash cement. Examples of gypsum include dihydrate gypsum, α-type or β-type hemihydrate gypsum, and anhydrous gypsum. These hydraulic inorganic substances may be used alone or in combination of two or more.

(Alkali resistant fiber)
The alkali-resistant fiber used in the present invention is not particularly limited as long as it has chemical durability against cement alkali, whether it is an organic fiber or an inorganic fiber. Examples of the alkali-resistant inorganic fiber include alkali resistance. Examples thereof include glass fiber, steel fiber (steel fiber), stainless fiber, and carbon fiber. Examples of the alkali-resistant organic fiber include polyvinyl alcohol (hereinafter sometimes referred to as PVA) fiber, polyolefin fiber (polyethylene fiber, polypropylene fiber, etc.), ultrahigh molecular weight polyethylene fiber, polyamide fiber (polyamide 6, Polyamide 6,6, polyamide 6,10, etc.), aramid fiber (particularly para-aramid fiber), polyparaphenylenebenzobisoxazole fiber (PBO fiber), acrylic fiber, rayon fiber (polynosic fiber, solvent-spun cellulose fiber, etc.), Examples include various alkali-resistant fibers such as polyphenylene sulfide fibers (PPS fibers) and polyether ether ketone fibers (PEEK fibers). These alkali resistant fibers may be used alone or in combination of two or more.

  Among these, alkali resistant glass fiber, carbon fiber, PVA fiber, polyolefin fiber (polyethylene fiber, polypropylene fiber, etc.), acrylic fiber, aramid fiber, etc. can be manufactured at low cost while having concrete reinforcement. Can be advantageously used.

  In particular, PVA fibers are preferred because of their good adhesion to hydraulic inorganic substances. The PVA fiber may be spun by a wet, dry-wet, or dry method using a spinning stock solution in which a PVA polymer is dissolved in a solvent.

  The fiber diameter of the alkali-resistant fiber is not particularly limited as long as the mixed hydraulic material exhibits a predetermined particle size, and can be selected from a wide range of 1 to 1000 μm, for example, 2 to 1000 μm. However, it may be about 3 to 900 μm (for example, 5 to 100 μm), more preferably about 5 to 800 μm (for example, 10 to 90 μm).

  The aspect ratio of the alkali-resistant fiber is not particularly limited as long as the mixed hydraulic material exhibits a predetermined range of particle sizes, but is usually used for short fibers. For example, the aspect ratio of the fiber is, for example, It may be about 5 to 1000, preferably about 8 to 900.

  The fiber strength of the alkali-resistant fiber is not particularly limited as long as the mixed hydraulic material exhibits a predetermined particle size, but may be, for example, 5 cN / dtex or more, preferably 6 cN / It may be dtex or more, more preferably 7 cN / dtex or more. In addition, although the upper limit of fiber strength is suitably set according to the kind of fiber, for example, 30 cN / dtex may be sufficient. In addition, fiber strength shows the value measured by the method described in the Example mentioned later.

  The ratio of the alkali-resistant fiber to the hydraulic material can be set as appropriate according to the type of fiber, fiber diameter, aspect ratio, etc., and the mixed hydraulic material has a predetermined range of particle sizes. Although not particularly limited, the ratio of the alkali-resistant fiber to the solid content of the hydraulic material may be, for example, about 0.1 to 5% by mass, and preferably about 0.3 to 4.5% by mass. Preferably, it may be about 0.5 to 4% by mass.

  The hydraulic material may contain various aggregates as necessary. Examples of such aggregates include fine aggregates, lightweight aggregates, and coarse aggregates. These aggregates may be used alone or in combination of two or more.

  Examples of the fine aggregate include fine particles having a particle size of 5 mm or less. Although not particularly limited as long as such particle size is satisfied, for example, sand such as river sand, mountain sand, sea sand, crushed sand, silica sand, slag, glass sand, iron sand, ash sand, calcium carbonate, artificial sand and the like It is done.

  Examples of lightweight aggregates include natural lightweight aggregates such as volcanic gravel, expanded slag and charcoal, and artificial lightweight aggregates such as foamed pearlite, foamed perlite, foamed black stone, vermiculite, and shirasu balloon.

  Coarse aggregates include those having a particle size of 5 mm or more and 85% or more by weight. For example, various gravels, artificial aggregates, recycled aggregates, and the like can be used.

  For hydraulic materials, various admixtures, for example, AE agents, fluidizing agents, water reducing agents, high performance water reducing agents, AE water reducing agents, high performance AE water reducing agents, thickeners, water retention agents, as appropriate. , A water repellent, a swelling agent, a curing accelerator, a setting retarder, and the like may be mixed therein. These admixtures may be used alone or in combination of two or more.

  If necessary, a water-soluble polymer substance may be added to the hydraulic material. Examples of the water-soluble polymer substance include cellulose ethers such as methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and hydroxypropyl methyl cellulose, polyvinyl alcohol, polyacrylic acid, and lignin sulfonate. You may use these individually or in combination of 2 or more types.

  The ratio of water contained in the hydraulic material may be, for example, about 20 to 80% in terms of water cement ratio (W / C), preferably 25 to 70%, more preferably 30 to 60%. Also good.

  In the present invention, a fiber-reinforced hydraulic cured body having high strength and design is produced by omitting the kneading step and the extrusion step by setting the mixed hydraulic material in a specific state. It becomes possible.

  The hydraulic material containing water is mixed by mixing means such as a known or conventional mixer. Further, the mixing order of the constituent materials can be carried out without any particular limitation.

  In the present invention, it is possible to directly feed the mixed hydraulic material into the mold without performing the kneading step. Here, a kneading | mixing process means the process changed from the state in which the hydraulic materials containing water are not integrated to the state which can show the tendency integrated as a whole. As the process of mixing hydraulic materials, after materials other than water are mixed, water is introduced and the materials come into contact with water, but the hydraulic materials in contact with water first come into contact with water. Reflecting this state, the mixing proceeds while existing independently in various sizes, and the whole becomes a small and uniform independent shape. In the present invention, the process up to this point is defined as a mixing process. In this case, the mixed hydraulic material shows a ratio of mesh-on and mesh-pass in a predetermined range described later.

  In the kneading step, the mixing further proceeds, and the integration proceeds gradually while the independent materials are bonded together. The term “integrated” also means a state in which the whole is in a bowl shape, or a state in which the whole flows without any interruption when it is poured into another container. The integrated material no longer shows the mesh-on, mesh-pass ratio that the mixed hydraulic material had.

In the mixed hydraulic material, the ratio of the amount passing through the mesh having a sieve opening of 20 mmΦ is 95% by weight or more, and the ratio of the amount not passing through the mesh having a sieve opening of 3 mmΦ is 95% by weight or more. is necessary. This is very important both for producing a homogeneous molded body and for uniformly filling the formwork uniformly. If a material larger than this rule is used, not only will there be many defects in the molded body, but defects will occur in the upper surface and end shape of the molded body, which is not preferable. On the other hand, it is not preferable to use a material smaller than this specification because the handling property is insufficient.
Preferably, in the mixed hydraulic material, the ratio of the amount passing through the mesh having a sieve opening of 15 mmΦ is 95% by weight or more and the ratio of the amount not passing through the mesh having a sieve opening of 2 mmΦ is 95% by weight or more. May be.
More preferably, the mixed hydraulic material has a ratio of an amount passing through a mesh with a sieve opening of 10 mmΦ being 95% by weight or more and a ratio of an amount not passing through a mesh with a sieve opening of 1 mmΦ being 95% by weight or more. There may be.

(Input process)
In the charging step, the hydraulic material mixed so as to have a predetermined particle size is charged into the mold without kneading. The injection into the mold can be performed without using an extruder. The mixed hydraulic material is weighed to a predetermined amount according to the size of the mold and is appropriately put into the mold by a feeder or the like.

  As long as the hydraulic material put into the mold can obtain a hydraulic inorganic molded body, it may be used as it is for the pressing step, but if necessary, the hydraulic material may be applied to the hydraulic material before the pressing step. Vibration may be applied. The vibration is usually performed by vibrating the formwork. By applying vibration, the hydraulic material can be more evenly distributed inside the mold.

  The frequency at the time of vibrating may be, for example, a frequency of 10 to 1000 Hz, preferably 20 to 900 Hz, more preferably 30 to 800 Hz. The amplitude may be, for example, about 0.1 to 20 μm, preferably about 0.5 to 18 μm, more preferably about 1 to 15 μm.

(Pressing process)
In the pressing step, the hydraulic material put into the mold is pressed by a press using an upper surface mold or a roll.
The pressure at the time of pressing can be appropriately set depending on the state of the hydraulic material, the form of the formwork, etc.
10-150 MPa, preferably 20-140 MPa, more preferably 30-130 MPa. If the pressure is lower than 10 MPa, the integration of the materials becomes insufficient. On the other hand, if the pressure exceeds 150 MPa, the fibers are damaged by pressing with the aggregate, not only the fiber strength is lowered, but also the durability of the formwork is impaired. It is.

  If necessary, vibration may be applied to the hydraulic material during the pressing step. The vibration is usually performed using a vibration press molding machine or the like. By applying vibration, the hydraulic material can be more evenly distributed inside the mold.

  The frequency at the time of vibrating may be, for example, a frequency of 10 to 1000 Hz, preferably 20 to 900 Hz, more preferably 30 to 800 Hz. The amplitude may be, for example, about 0.1 to 20 μm, preferably about 0.5 to 18 μm, more preferably about 1 to 15 μm.

  Moreover, you may perform a press, heating as needed. For example, the heating temperature may be about 40 to 90 ° C, preferably about 45 to 85 ° C, and more preferably about 50 to 80 ° C.

  A fiber-reinforced hydraulic inorganic molded body can be obtained by performing a curing process, a drying process, and the like on the pressed pressed object as necessary.

(Fiber reinforced hydraulic inorganic molding)
The fiber-reinforced hydraulic inorganic molded body obtained by such a manufacturing method has design properties according to the shape of the mold, and the hydraulic inorganic molded body has, for example, a thickness in the main body, for example, , About 5 to 100 mm, preferably about 10 to 90 mm.

Further, since the fibers are well dispersed in the hydraulic material even though it does not have a kneading step, the fiber has sufficient strength for use. For example, the bending strength is 5 N / mm ^{2 to} 30 N. / Mm ² is obtained.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to these Examples.

[Fiber strength measuring method (cN / dtex)]
Evaluation was made according to JIS L1015 “Testing method for chemical fiber staples (8.5.1)”.

[Measurement method of fiber diameter and aspect ratio]
Evaluation was made according to JIS L1015 “Testing method for chemical fiber staples (8.5.1)”.

[Particle size evaluation of hydraulic materials]
Take out 1kg of mixed hydraulic material, vibrate for 30 seconds against various sieves with sieve openings of 1mm to 20mm, screen, do not pass the mesh and the proportion of mesh passing The amount (mesh-on) ratio was investigated respectively.

[Evaluation of formability]
Visual evaluation was performed from the surface roughness and shape of the molded body after the mixed hydraulic material was put into a predetermined mold and press-molded. Visual evaluation was made into the following five-step evaluation.
○: The surface roughness is smooth and has the same shape as the mold.
○ △: A part of the surface is rough, but has the same shape as the mold,
Alternatively, the surface roughness is smooth, but a defect exists in a part of the shape.
(Triangle | delta): A part of surface is rough and a defect exists also in a part of shape.
Δ ×: The entire surface is rough, but the shape defect is only a part,
Alternatively, a part of the surface is rough, but there are many defects in the shape.
X: The entire surface is rough, and there are many defects in the shape.

[Bending strength]
From the specimen, three strip-shaped specimens having a length of about 150 mm and a width of about 50 mm were cut out per specimen. Then, in order to adjust the moisture content at the time of measurement of a test piece uniformly, the cut-out test piece was dried for 72 hours with the dryer adjusted to 40 degreeC. The bending strength was measured according to JIS A 1408. The bending strength was measured using an autograph AG5000-B manufactured by Shimadzu Corporation with a test speed (loading head speed) of 2 mm / min and a central loading method with a bending span of 100 mm. The bending strength was evaluated as follows.
◯: When the bending strength is 95% or more of a molded product having the same composition obtained through kneading and extrusion.
(Circle) (triangle | delta): When bending strength is 85-95% of the molded object of the same composition obtained through kneading | mixing and extrusion.
(Triangle | delta): When bending strength is 75-85% of the molded object of the same composition obtained through kneading | mixing and extrusion.
Δ ×: When the bending strength is 65% or more and less than 75% of a molded body having the same composition obtained through kneading and extrusion.
X: When bending strength is less than 65% of the molded body of the same composition obtained through kneading and extrusion.

[Example 1]
(Mixing process)
About the mixing | blending mixing | blending, the following were used.
Normal Portland cement: 50% by mass
No. 8 quartz sand: 7.5% by mass
Silica fume (EFACO manufactured by Sakai Kogyo Co., Ltd.): 4.5% by mass
Calcium carbonate (Sankyo Flour Milling Co., Ltd. Grade 1, Brain value 4000): 34% by mass
Pulp (dry pulverized pulp): 3% by mass
Reinforcing fiber: PVA-1 (manufactured by Kuraray Co., Ltd., fiber diameter 7 μm, aspect ratio 571, fiber strength 14 cN / dtex): 1% by mass
Among the above blended blends, the pulp was first put into a van type mixer manufactured by MG Co., Ltd., kneaded at 800 rpm for 60 seconds, and then the rest was added and further mixed for 180 seconds. Thereafter, 23% by mass of water was added to the total mass of the mixture and further mixed for 240 seconds.

  The mixed hydraulic material is 100% by weight mesh pass for a mesh with a sieve opening of 20 mm, 100% by weight mesh pass for a mesh with a sieve opening of 15 mm, 96% by weight mesh pass for a mesh with a sieve opening of 10 mm, It was 100% by weight mesh-on for a mesh having a mesh opening of 1 mm, 100% by weight on for a mesh having a mesh opening of 2 mm, and 96% by weight on a mesh having a mesh opening of 3 mm.

(Input process)
The mixed hydraulic material was filled in a 300 mm × 300 mm mold with a target thickness of 40 mm.

(Pressing process)
The hydraulic material filled in the mold was pressed using a vibration press machine at 70 ° C. under a pressure of 4 MPa and a vibration frequency of 200 Hz and an amplitude of 1 μm.

  The pressed product to be pressed was demolded and then subjected to natural curing at 20 ° C. for 2 weeks in a sealed state so as not to evaporate moisture with a plastic film. Table 1 shows the properties of the obtained fiber-reinforced hydraulic inorganic molded body.

[Example 2]
A fiber-reinforced hydraulic inorganic molded body in the same manner as in Example 1 except that PVA2 (manufactured by Kuraray Co., Ltd., fiber diameter 26 μm, aspect ratio 231, fiber strength 12 cN / dtex) is used as the reinforcing fiber instead of PVA1. Got. Table 1 shows the properties of the obtained fiber-reinforced hydraulic inorganic molded body.

  In addition, the mixed hydraulic material is 100% by weight mesh for a mesh with a mesh opening of 20 mm, 98 wt% mesh for a mesh with a mesh opening of 15 mm, and 92 wt% mesh for a mesh with a mesh opening of 10 mm. It was 100% by weight mesh on a pass, mesh opening of 1 mm, 100% by weight mesh on mesh of 2 mm, and 98% by weight mesh on mesh of 3 mm.

[Example 3]
The fiber reinforced hydraulic property is the same as in Example 1 except that PP (Kuraray prototype, fiber diameter 12 μm, aspect ratio 429, fiber strength 10.5 cN / dtex) is used as the reinforcing fiber instead of PVA1. An inorganic molded body was obtained. Table 1 shows the properties of the obtained fiber-reinforced hydraulic inorganic molded body.

  The mixed hydraulic material is 100% by weight mesh for a mesh with a mesh opening of 20 mm, 99% by weight for a mesh with a mesh opening of 15 mm, and 94% by mesh for a mesh with a mesh opening of 10 mm. It was 100% by weight mesh on a pass, 1 mm mesh mesh, 100% by weight mesh on 2 mm mesh screen, and 97% by weight mesh on 3 mm mesh screen.

[Comparative Example 1]
A hydraulic inorganic molded body was obtained in the same manner as in Example 1 except that the reinforcing fiber was not used. Table 1 shows the properties of the obtained hydraulic inorganic molded body.

  The mixed hydraulic material is 100% by weight mesh for a mesh with a mesh opening of 20 mm, 100% by weight for a mesh with a mesh opening of 15 mm, and 100% by mesh for a mesh with a mesh opening of 10 mm. It was 98 wt% mesh-on for a pass, 1 mm mesh mesh, 91 wt% mesh-on for 2 mm mesh screen, and 85 wt% mesh-on for 3 mm mesh screen.

[Comparative Example 2]
A fiber-reinforced hydraulic inorganic molded body in the same manner as in Example 1 except that PVA3 (manufactured by Kuraray Co., Ltd., fiber diameter 7 μm, aspect ratio 1142, fiber strength 14 cN / dtex) is used as the reinforcing fiber instead of PVA1. Got. Table 1 shows the properties of the obtained fiber-reinforced hydraulic inorganic molded body.

  The mixed hydraulic material is 54 wt% mesh pass for a 20 mm mesh opening, 38 wt% mesh pass for a 15 mm mesh opening, and 22 wt% mesh for a 10 mm mesh opening. It was 100 wt% mesh-on for a pass, 1 mm mesh mesh, 100 wt% mesh-on for 2 mm mesh screen, and 100 wt% mesh-on for 3 mm mesh screen.

[Reference Example 1]
(Mixing process)
In Example 1, mixed in the same manner as in Example 1 except that 33% by weight of calcium carbonate and 1% by weight of Metroise SNB-60T manufactured by Shin-Etsu Chemical Co., Ltd. were newly added. Carried out.

(Kneading process)
The hydraulic material mixed through the mixing step was kneaded for 5 minutes with a Kneader Luder manufactured by MIG Corporation. The kneaded hydraulic material was 100 wt% mesh-on with respect to a mesh having a sieve opening of 20 mm.

(Extrusion process)
The mixed hydraulic material was put into a vacuum extrusion molding machine manufactured by MIG Co., Ltd., and extrusion was performed from a die having a width of 50 mm and a thickness of 10 mm. The obtained hydraulic molded body was cut into six pieces having a length of 300 mm, and these were placed in parallel to be put in a 300 mm × 300 mm mold.

(Pressing process)
The hydraulic material contained in the mold was pressed using a vibration press machine at 70 ° C. and a pressure of 4 MPa while applying vibration of 200 Hz and amplitude of 1 μm.

The pressed product to be pressed was demolded and then subjected to natural curing at 20 ° C. for 2 weeks in a sealed state so as not to evaporate moisture with a plastic film.
Table 1 shows the properties of the obtained fiber-reinforced hydraulic inorganic molded body.

As shown in Table 1, Examples 1 to 3 can have the same degree of design as Reference Example 1 formed by standard extrusion molding, although the kneading step is not performed. Further, the bending strength is almost the same level as in Reference Example 1.
On the other hand, since Comparative Example 1 does not have fibers, the strength of the molded body is insufficient. Moreover, in the comparative example 2 in which the mixed hydraulic material does not show a specific particle size distribution, both the design properties and the strength are inferior.

  In the method for producing a fiber-reinforced hydraulic inorganic molded body of the present invention, it is possible to omit the steps of kneading and extruding, thereby improving productivity and easily and evenly forming a complex-shaped formwork. Since it can be filled, a molded body comparable to the design and strength of the conventional molded body can be obtained by an efficient manufacturing method.

Claims (8)

A mixing step of mixing water, a hydraulic inorganic substance, and a hydraulic material including at least an alkali-resistant fiber;
A charging step of charging the mixed hydraulic material into the mold without kneading;
A pressing step of pressing the hydraulic material put into the mold with a press;
Comprising at least
The mixed hydraulic material is a fiber-reinforced water in which the ratio of the amount passing through a mesh having a sieve opening of 20 mmΦ is 95% by weight or more and the ratio of the amount not passing through a mesh having a sieve opening of 3 mmΦ is 95% by weight or more. A method for producing a hard inorganic molded body.   2. The production method according to claim 1, wherein the alkali-resistant fiber is at least one selected from the group consisting of alkali-resistant glass fiber, carbon fiber, polyvinyl alcohol fiber, polyethylene fiber, polypropylene fiber, acrylic fiber, and aramid fiber. Method.   The manufacturing method according to claim 1 or 2, wherein vibration is applied to the mixture charged into the mold.   The manufacturing method according to any one of claims 1 to 3, wherein the alkali-resistant fiber has a fiber diameter of 2 to 1000 µm and an aspect ratio of 5 to 1000.   The manufacturing method according to any one of claims 1 to 4, wherein the alkali-resistant fiber has a fiber strength of 5 cN / dtex or more.   The manufacturing method as described in any one of Claims 1-4 WHEREIN: The ratio of the alkali resistant fiber with respect to solid content of a hydraulic material is 0.1-5 mass%.   The manufacturing method according to any one of claims 1 to 6, wherein the alkali-resistant fiber is a polyvinyl alcohol fiber.   The fiber reinforced hydraulic inorganic molded object manufactured with the manufacturing method as described in any one of Claims 1-7.