JP2007217220A - Method for manufacturing porous concrete formed product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous concrete formed product instantly releasable from a formwork even in case of a high formed product in height or in case of using coarse aggregate having a big maximum particle size. <P>SOLUTION: The method for manufacturing the porous concrete formed product comprises the steps of casting a kneaded mixture of a cement powder, coarse aggregate and water into a formwork provided with nozzles in a plurality of directions of the vertical part, compacting the mixture, spraying a quick setting agent from the nozzles, instantly releasing it from the formwork and thereafter curing it. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a porous concrete molded body that can be instantly demolded even when the molded body height is high or when coarse aggregate having a large maximum particle size is used.

Porous concrete is porous concrete having continuous voids obtained by kneading coarse aggregate adjusted to a substantially constant particle size with cement paste in a predetermined composition, molding with a mold, and curing.
Porous concrete has the property that water and air can freely pass through continuous voids, so it has high water permeability and is used as a drainage pavement to improve the safety of automobile traffic and absorbs sound. Since it has, it has been utilized as a sound absorbing material that absorbs noise when the automobile travels. In addition to on-site porous concrete, porous concrete molded bodies are used for interlocking concrete blocks such as sidewalks as road concrete.
Furthermore, in recent years, a porous concrete molded body has been put into practical use for river revetment in order to protect the ecosystem while maintaining flood safety.

  As a method for producing such a porous concrete molded body, Patent Document 1 specifies the consistency and coating thickness of paste or mortar covering coarse aggregate, vibration conditions and pressure conditions during molding, Discloses an immediately-destructed porous concrete molded body having a bending strength and a large water permeability, and a method for producing the same.

  Patent Document 2 is suitable as a pavement material such as a roadway, has a high water permeability of a porosity of 25% or more, and can obtain a bending strength equal to or higher than that of ordinary concrete with a small polymer cement ratio. Disclosed are porous concrete compacts and cast-in-place porous concrete that are instantly demolded.

  Patent Document 3 has a large water permeability coefficient and strength by using cement powder, water reducing agent, fine aggregate, coarse aggregate, gypsum and water in a specific blending ratio, and kneading. There is disclosed an immediate-removed porous concrete molded body in which the workability of an object is good and work such as molding is easy.

  In any of the methods described above, a porous concrete molded body is produced by immediate demolding using a coarse aggregate having a porous concrete molded body having a height of 80 mm or less and a maximum particle size of 20 mm or less. However, when producing a porous concrete molded body using a coarse aggregate having a high height of the porous concrete molded body or a large maximum particle size, it cannot be removed immediately and the initial setting time of the paste (2 If the mold was not removed after a lapse of time, the molded body was broken.

JP-A-9-87053 Japanese Unexamined Patent Publication No. 2000-119074 JP 2003-12361 A

  In view of the situation of the prior art as described above, the present invention eliminates immediate removal even when the height of the porous concrete molded body is high or when the porous concrete molded body using coarse aggregate having a large maximum particle size is manufactured. It aims at providing the manufacturing method of the porous concrete molded object which can be shape | molded.

  As a result of diligent research in view of the above problems, the inventor poured a cement-based powder, coarse aggregate and water kneaded material into a mold in which nozzles are installed in a plurality of directions of the vertical portion, and after compaction, the nozzle By spraying a quick setting agent from the above, it is possible to produce a porous concrete molded body by immediate demolding even when the height of the molded body is high or when coarse aggregate with a large maximum particle size is used. And found the present invention.

That is, the present invention
(1) A mixture of cement-based powder, coarse aggregate and water is poured into a mold with nozzles installed in multiple directions in the vertical part, and after compaction, a rapid setting agent is sprayed from the nozzles for immediate removal. Molding and then curing, a method for producing a porous concrete molded body;
(2) The method for producing a porous concrete molded body according to (1), wherein the vertical height of the porous concrete molded body is 80 mm or more;
(3) The method for producing a porous concrete molded body according to (1) or (2), wherein a coarse aggregate having a maximum particle size of more than 20 mm is used;
I will provide a.

According to the method for producing a porous concrete molded body of the present invention, even if the molded body is high or a coarse aggregate having a large maximum particle size is used, immediate demolding is possible. The use rotation efficiency of the frame can be increased.
In addition, because it is possible to immediately demold a porous concrete molded body with a high height, it is also possible to use a vertical formwork, which can increase the number of molds installed and increase the production efficiency of the porous concrete molded body. Can do.

  Hereinafter, embodiments of the present invention will be described in detail.

  According to the present invention, the method for producing a porous concrete molded body that is immediately removed from the mold includes kneading the cement-based powder, coarse aggregate and water with a kneader, pouring the kneaded material into a mold with a nozzle installed, and vibrating with a compacting machine. After the compaction, the concrete is rapidly solidified by spraying a rapid setting agent from the nozzle, immediately demolded, and then cured.

  The cementitious powder used in the present invention is not particularly limited, for example, ordinary, early strength, ultra-early strength, moderate heat, low heat, sulfate resistant and other portland cement, blast furnace, fly ash, silica, etc. Can be used.

As the coarse aggregate used in the present invention, crushed stone, gravel, recycled aggregate or a mixture thereof, lightweight aggregate and the like can be used. As described above, when a coarse aggregate having a maximum particle size of 20 mm or more is used, immediate demolding cannot be performed. However, in the present invention, as described later, the maximum particle size is obtained by spraying a quick setting agent after compaction. Even if a coarse aggregate having a diameter of 20 mm or more is used, immediate demolding is possible.
Therefore, in the present invention, the particle size range of the coarse aggregate is appropriately determined according to the use of the porous concrete molded body, and there is no restriction that the maximum particle size must be 20 mm or less.
The compounding amount of the coarse aggregate in the kneaded product is 300 to 800 parts by weight, preferably 400 to 700 parts by weight, with respect to 100 parts by weight of the cementitious powder. If it is 800 parts by weight or more, the strength becomes too low, and if it is less than 300 parts by weight, the porosity becomes small and continuous voids cannot be secured.

  If necessary, fine aggregates such as crushed sand, river sand, sea sand, and quartz sand can also be blended.

The amount of water blended varies depending on the type of cementitious powder and the type and amount of water reducing agent, but is about 12 to 45 parts by weight with respect to 100 parts by weight of cementitious powder.
If it is 45 parts by weight or more, the paste becomes too soft and dripping, the bottom surface becomes clogged and the required strength cannot be secured, and if it is less than 12 parts by weight, the paste is too hard and gives vibration. In this case, the required strength cannot be ensured.

As the water reducing agent, a known high performance water reducing agent, AE water reducing agent, high performance AE water reducing agent, etc. can be used in a normal addition amount, and the addition amount is 0.25 to 5 weights with respect to 100 parts by weight of cement. About a part.

The kneading machine is not particularly limited, and a normal concrete kneading machine can be used. Examples thereof include a biaxial forced kneading mixer, an omni type mixer, and a pan type mixer.
As a kneading method, a porous concrete material is charged into a kneader and kneaded. The kneading time is about 0.5 to 3 minutes, and the kneading is continued until the granules independent of each other with the cement paste coated on the coarse aggregate are formed.

  The formwork is the same as that for producing a general concrete molded body, and a metal plate such as an iron plate or an aluminum plate, a rectangular parallelepiped shape using wood or the like, a columnar shape, etc. can be used. A frame can also be used. The mold used in the present invention is provided with a hole into which a nozzle for spraying a quick setting agent is inserted.

As the compacting machine, a form vibration method, a shaking table method, or the like can be used.
As a compaction method, the kneaded material is put into a predetermined mold and compacted by a compaction machine. The frequency is preferably 40 Hz to 130 Hz, and the vibration time is preferably 3 seconds to 15 seconds. Further, compaction may be performed under pressure, and a hydraulic or pneumatic pressurizing device or the like can be used.

As the nozzle for spraying the quick setting agent, either a one-fluid nozzle or a two-fluid nozzle may be used. From the viewpoint of ease of handling, a one-fluid nozzle is preferable, and a nozzle capable of spraying at a wide angle is preferable. .
The installation position (height, direction) and the number of installation of the spray nozzle in the vertical part of the formwork vary depending on the height of the molded body, the maximum particle size of the coarse aggregate used, etc., but at least 1/2 of the height of the molded body It is preferable to provide four rows in the height, and when it is preferable to increase the number of installations, such as when the height of the molded body is high, a plurality of rows are provided with the height of the mold frame vertical portion (molded body height) divided equally. This is effective for a self-supporting molded product that can be immediately removed.

As the quick setting agent, the kind is not particularly limited as long as it can quickly set the cement paste, and inorganic salt type, cement mineral type, natural mineral type, organic type and the like can be used, preferably Satisfies the Japan Society of Civil Engineers standard (JSCE-D102-2001: Quality standard for quick setting agent for sprayed concrete).
Since the liquid quick setting agent is excellent in terms of ease of handling such as cleaning of the nozzle part, in the case of a powder type quick setting agent, it can be sprayed as it is, but it can be used as a milk by kneading with water. preferable.

The total spray amount of the quick setting agent varies depending on the size of the porous concrete molded body and the like, but it is sufficient that the molded body is released immediately and the molded body is self-supporting.
In the present invention, “immediate demolding” means that after the quick setting agent is sprayed from the nozzle to the compacted compact, it is placed for several seconds to several minutes, and after the setting by the quick setting agent spraying, the mold is demolded. To do.

  The curing method of the molded product immediately removed is not particularly limited, and can be cured by a commonly used method such as air curing, steam curing, autoclave curing, and the like.

  EXAMPLES Next, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited only to these Examples.

Examples 1 to 7, Comparative Examples 1 and 2
Materials and Equipment The raw materials and equipment used in the examples and comparative examples are as follows.
<Raw material of porous concrete compact>
Coarse aggregate: Crushed stone 4020 and Crushed stone 2013 (from Takatsuki, Osaka Prefecture)
Cement: Ordinary Portland cement (manufactured by Sumitomo Osaka Cement Co., Ltd.)
Water reducing agent; High-performance AE water reducing agent "Mighty 3000S" (trade name) (manufactured by Kao Corporation)
Water; tap water quick set; liquid quick set based on water-soluble aluminum salt "Meiko SA Ecoshot" (trade name) (manufactured by NM Co., Ltd.)
<Kneading machine>
Biaxial forced kneading mixer (manufactured by Taiheiyo Kiko Co., Ltd.) Capacity 55L
<Compacting machine>
Shaking table type vibrator (manufactured by EXEN) Frequency 47.5Hz
<Formwork>
PVC cylindrical shape with a diameter of 30 cm, height: the same as the height of the compact <quickening agent spray nozzle>
Wide-angle fan type nozzle (manufactured by Ikeuchi Co., Ltd.)
Spray angle: 140 °, spray pressure: 0.15 MPa, spray flow rate: 10 L / min
The nozzle positions shown in Table 1 were provided in four directions.

The raw material of the molding methods porous concrete shaped bodies coarse aggregate: 1394kg / m ^3, cement 253 kg / m ^3, water: 76 kg / m ^3, water reducing agent: were charged into a kneader at a rate of 3.54kg / m ^3, 2 Kneaded for a minute.

Prepare a PVC cylindrical formwork that has the same vertical height as the product height in Table 1 and a quick setting agent spray nozzle at the nozzle position in Table 1. Molding was performed at 47.5 Hz for 10 seconds. However, when the height of the molded body exceeded 20 cm, compaction was performed in multiple steps every 20 cm.

  After compaction, the molded product obtained by spraying the rapid setting agent from the nozzle for 3 seconds and immediately demolded after 15 seconds was cured in the air to obtain a porous concrete molded body.

Evaluation of the self-supporting property of the demolded compact When the self-supporting property of the porous concrete demolded compact that has been immediately demolded is visually evaluated and the vertical end surface of the porous concrete demolded compact is self-supporting without collapsing, “○”, some However, when it collapsed, it was set as “x”. The results are shown in Table 1.

  Examples 1 to 3 use a coarse aggregate (crushed stone 2013) having a maximum particle size of 20 mm, a molded body height of 20 cm or more, and a rapid setting agent sprayed from a nozzle to immediately demold the porous concrete demolded body. It is. On the other hand, Comparative Example 1 is a porous concrete demolding body using a coarse aggregate (crushed stone 2013) having a maximum particle size of 20 mm, having a molded body height of 20 cm, and immediately demolding without spraying a quick setting agent. .

  Examples 4 to 6 use a coarse aggregate (crushed stone 4020) having a maximum particle size of 40 mm, a molded body height of 10 cm or more, a rapid setting agent sprayed from a nozzle, and immediately demolded to remove porous concrete. Is the body. On the other hand, Comparative Example 2 is a porous concrete demolding body using a coarse aggregate (crushed stone 4020) having a maximum particle size of 40 mm, having a molded body height of 10 cm, and immediately demolding without spraying a quick setting agent. .

  From the results shown in Table 1, the porous concrete demolded body of the example was self-supporting without collapsing the upper end portion, and the porous concrete demolded body could be manufactured. It turns out that a part collapse | crumbles and cannot become independent and a porous concrete molded object cannot be manufactured.

It is a figure which shows the characteristic of the porous concrete molded object manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Formwork 2 Nozzle 3 Coarse aggregate 4 Cement paste 5 Space | gap a, b, c The installation position of the nozzle in a formwork

Claims (3)

The mixture of cement powder, coarse aggregate and water is poured into a mold having nozzles installed in a plurality of directions in the vertical part, and after compaction, the rapid setting agent is sprayed from the nozzle and immediately demolded. A method for producing a porous concrete molded body, which is then cured. The manufacturing method of the porous concrete molded object of Claim 1 whose vertical height of a porous concrete molded object is 80 mm or more. The method for producing a porous concrete molded body according to claim 1 or 2, wherein a coarse aggregate having a maximum particle size exceeding 20 mm is used.

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