JP2011057514A - Concrete panel molded article and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete panel molded article in which filling property is good and moldability is good, which has high strength, in which there is neither a crack nor warpage, and which is flat and suitable for mass production, and a method for manufacturing the same. <P>SOLUTION: The concrete panel molded article is a concrete panel which comprises pressurization vibration forming a concrete composition which includes: (A) cement; (B1) a synthetic spherical silicon dioxide fine powder or (B2) a fine powder of a special silica quality which has silicon dioxide as a principal component and contains zirconium oxide; (C) an aggregate; (D) a fiber; and water. In the component (B1), a silicon dioxide content is 99 mass% or more, an ignition loss at 1,000±50°C is 0.3 mass% or less, and a BET specific surface area is 1-4.8 m<SP>2</SP>/g. The component (B2) contains 91-95 mass% of silicon dioxide and 3-5 mass% of zirconia, and has a BET specific surface area of 1-20 m<SP>2</SP>/g. In the concrete composition, a content of the component (B1) or the component (B2) is 10-40 pts.mass based on the component (A) of 100 pts.mass a mass ratio of water/[sum total of the component (A), and the component (B1) or the component (B2)] is 0.16-0.28, and a unit water amount is 100-175 kg/m<SP>3</SP>, and the component (D) is included by 1-5 volume%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a concrete panel molded body and a method for producing the same, and more particularly to a flat concrete panel molded body having excellent filling properties, high strength, suppressing cracking, and no warpage, and a method for producing the same.

Conventionally, as a method for repairing the inner surface of an existing waterway such as agricultural water and sewerage, a so-called concrete replacement method is generally used in which a defective portion of the existing concrete on the inner surface is removed and concrete is re-launched on the removed portion. is there.
In this method, there are operations such as shaving off a defective portion of existing concrete, carrying it out, and driving in new concrete, which increases the construction period.

For this reason, JP 2007-146604 A (Patent Document 1) discloses that a repair panel having a contact leg attached to a wall to be repaired is connected and spread on the inner surface of an existing water channel, and itself is used as a formwork. A method of injecting concrete into the gap is shown.
Japanese Patent Application Laid-Open No. 2001-270761 (Patent Document 2) includes at least a repair panel comprising a hardened body of a mixture containing cement, pozzolanic fine powder, aggregate having a particle diameter of 2 mm or less, water, and a water reducing agent. It is shown to be applied as a repair panel.

The sewer repair panel is a part of the sewer concrete that has deteriorated due to the erosion of sulfuric acid, etc., and then refills the cross-sectional defect with mortar, concrete, etc., and the surface is bonded with mortar, etc. A panel for surface coating that is used by being fixed by a method.
Examples of the pozzolanic fine powder include silica fume, silica dust, fly ash, slag, volcanic ash, silica sol, and precipitated silica.

In general, in concrete using Portland cement, cement hydrate itself as a binder is mainly composed of a calcium salt that is highly reactive with acids, and therefore has little resistance to strong acids.
Therefore, when concrete products using Portland cement are used for the purpose of draining acidic water, or when hydrogen sulfide is generated from the wastewater and sulfuric acid is generated by the action of sulfur-oxidizing bacteria, There is a problem that the life is short due to erosion due to expansion and collapse due to calcium sulfate generation, and repair is required at an early stage.
As a general repair method in such a case, there is a method in which a deteriorated portion is applied, mortar is applied if necessary, and an organic resin is lined thereon, but the resin is manually applied to the surface. For this reason, there are problems such as very poor construction efficiency and the fact that the organic solvent to be used is harmful to the human body, and there is a need for a solution especially in the repair of deteriorated sewer concrete.

  In addition, when a thin-walled concrete panel is manufactured with high-strength mortar or high-strength concrete with a large amount of binder powder and water, the amount of self-shrinkage and drying shrinkage is large, and cracking occurs early due to repeated drying and wetting. There are problems such as warping on the panel board.

In order to improve the flowability and increase the strength of concrete, silica fume is generally mixed with various cements as an admixture.
This silica fume is a spherical ultrafine particle material with a particle size of about 0.1 to 0.3 μm mainly composed of amorphous silicon dioxide produced as a by-product during the production of metallic silicon and ferrosilicon, and when mixed with mortar or concrete It is known that the cured body is densified and its strength is enhanced by its high pozzolanic activity and microfiller effect.
However, the primary particles of silica fume are ultrafine particles having a particle size of about 0.1 to 0.3 μm, and usually aggregate to form secondary particles of several to several tens of μm in size. Dispersibility is not good.
Silica fume is a by-product of the production of metallic silicon and ferrosilicon, so the quality is not stable and contains several percent of various impurities such as unburned carbon, sulfur trioxide, and magnesium oxide. When the silica fume is used as an admixture for cement, impurities need to adjust the required amount of a chemical admixture such as a high-performance water reducing agent or an AE agent each time.

  On the other hand, a method has been proposed in which fine silica fume is melted and spheroidized in a burner flame to produce spherical silica particles having an average particle size of less than 8 μm and a relatively large particle size (Patent Document 3). Although these spherical silica particles have good handleability and have the effect of improving the fluidity of the concrete composition, inorganic impurities such as magnesium oxide mixed in silica fume cannot be removed, and the quality of the concrete is stabilized. There is a problem that it is difficult.

JP 2007-146604 A JP 2001-270761 A JP 2001-97712 A

An object of the present invention is to overcome the above-mentioned problems, and to provide a concrete panel molded body that is flat and suitable for mass production and has good strength, good moldability, high strength, no cracks and warpage, and a method for producing the same. Is to provide.
Therefore, it can be effectively used particularly as a concrete panel for repairing water channels.

In order to solve the above-mentioned problems, a synthetic spherical silicon dioxide fine powder having a specific shape or a special silica fine powder having a specific surface area of 1 to ²⁰ m ² / g according to the BET method is used at a specific ratio with respect to the cement. By adding fiber and applying pressure vibration molding, concrete panel moldings, especially for waterways, with high strength and compactness, with low self-shrinkage and small dry shrinkage and reduced warpage. Found that the body can be obtained.

The concrete panel molded body of the present invention comprises (A) cement, (B1) synthetic spherical silicon dioxide fine powder or (B2) special siliceous fine powder containing silicon oxide as a main component, (C) aggregate, D) A concrete panel formed by pressure-vibration molding of a concrete composition containing fibers and water, wherein the component (B1) has a silicon dioxide content of 99% by mass or more and is ignited at 1000 ± 50 ° C. Weight loss is 0.3% by mass or less, BET specific surface area is 1 to 4.8 m ² / g, (B2) component contains 91 to 95% by mass of silicon dioxide and 3 to 5% by mass of zirconia, and has a BET ratio Surface area is 1-20 m < ² > / g, In the said concrete compound, content of (B1) component or (B2) component is 10-40 mass parts with respect to 100 mass parts of (A) component, water / [ (A) component and Component (B1) or (B2) the sum of the components] and unit water mass ratio is from 0.16 to 0.28 is 100~175kg / ^{m 3,} to include 1-5 volume% component (D) It is a concrete panel molded body characterized.
Preferably, in the concrete panel molded body of the present invention, the concrete panel molded body further includes (E) a water reducing agent and / or (F) an expanding material.

In addition, the method for producing a concrete panel molded body of the present invention includes (A) cement, (B1) synthetic spherical silicon dioxide fine powder, or (B2) special siliceous fine powder containing silicon oxide as a main component, and (C ) Aggregate, (D) Fiber and water are added, and the component (B1) has a silicon dioxide content of 99% by mass or more, an ignition loss at 1000 ± 50 ° C. of 0.3% by mass or less, and BET The specific surface area is 1 to 4.8 m ² / g, the component (B2) contains 91 to 95% by mass of silicon dioxide and 3 to 5% by mass of zirconia, and the BET specific surface area is 1 to ²⁰ m ² / g. The (B1) component or the (B2) component is blended so that the content of the (B1) component or the (B2) component is 10 to 40 parts by mass with respect to 100 parts by mass of the (A) component, and water is added. Water / [(A) component and (B1) component or (B2 The total] weight ratio of the components is formulated to and unit water is 0.16 to 0.28 is 100~175kg / ^{m 3,} the concrete mix was prepared by uniformly kneading was prepared A method for producing a concrete panel molded body, comprising: putting a concrete composition into a panel form, forming by compaction by pressure vibration, and immediately removing the mold and performing a curing treatment.

  Preferably, in the concrete panel molded body of the present invention, (E) a water reducing agent and / or (F) an expanding material is further added.

The concrete panel molded body of the present invention can be made into an inexpensive concrete panel molded body having good filling properties and being dense, exhibiting high strength, excellent moldability, and free from cracks and warpage.
Furthermore, in addition to the above effects, the concrete panel molded body of the present invention can improve wear resistance, that is, surface smoothness.
Moreover, the method for producing a concrete panel molded body of the present invention can efficiently produce the concrete panel molded body in a large amount at a low cost.

An exemplary embodiment for carrying out the present invention will be described below.
The concrete panel molded body of the present invention comprises (A) cement, (B1) synthetic spherical silicon dioxide fine powder or (B2) special siliceous fine powder containing silicon oxide as a main component, (C) aggregate, D) A concrete panel formed by pressure-vibration molding of a concrete composition containing fibers and water, wherein the component (B1) has a silicon dioxide content of 99% by mass or more and is ignited at 1000 ± 50 ° C. Weight loss is 0.3% by mass or less, BET specific surface area is 1 to 4.8 m ² / g, (B2) component contains 91 to 95% by mass of silicon dioxide and 3 to 5% by mass of zirconia, and has a BET ratio Surface area is 1-20 m < ² > / g, In the said concrete compound, content of (B1) component or (B2) component is 10-40 mass parts with respect to 100 mass parts of (A) component, water / [ (A) component and Component (B1) or (B2) the sum of the components] mass ratio is 0.16 to 0.28 at and unit water is 100~175kg / ^{m 3,} comprises 1-5 volume% component (D), concrete Panel molded body.

There is no restriction | limiting in particular as cement (A) in the concrete compound used for the concrete panel molded object of this invention, From the cement currently used for the conventional concrete product, it is a use of the obtained concrete panel molded object. Depending on your choice, you can make the right choice.
Examples of such cement include at least one selected from ordinary portland cement such as normal, moderate heat, low heat, early strength, ultra-early strength, sulfate resistance, mixed cement such as blast furnace cement, fly ash cement and silica cement. Can be illustrated.

Further, the concrete composition contains a siliceous component of (B1) synthetic spherical silicon dioxide fine powder or (B2) special siliceous fine powder having silicon dioxide as a main component and the balance being zirconium oxide.
The synthetic spherical silicon dioxide fine powder used as the component (B1) is a fine particle material mainly composed of amorphous silicon dioxide. For example, the metal silicon powder is ignited in an oxygen-containing atmosphere to form a combustion flame. Thus, it is a synthetic product produced by continuously oxidizing and burning metal silicon powder.
Moreover, the silicon dioxide powder may coexist at the time of oxidative combustion of the metal silicon powder to burn impurities in the silicon dioxide powder.
Because it is such a synthetic product, unlike silica fume, which is a by-product during production of other materials and contains a large amount of impurities, the silicon dioxide content is 99% by mass or more, and the ignition loss at 1000 ± 50 ° C. is 0.3%. It is a high purity of less than wt%, contains almost no impurities harmful to mortar and concrete such as unburned carbon, sulfur trioxide and magnesium oxide, and has a BET specific surface area of 1 to 4.8 m ² / g. It is a spherical silicon dioxide fine powder having a large particle size.
Here, the ignition loss is measured by JIS A 6201 “fly ash for concrete”, and the BET specific surface area is measured by “nitrogen adsorption method”.
In addition, since the silicon dioxide content is 99% by mass or more and the loss on ignition at 1000 ± 50 ° C. is 0.3% by weight or less, since it contains almost no harmful impurities in mortar and concrete, it has a stable nature. Can be obtained.

The synthetic spherical silicon dioxide fine powder used in the present invention has a BET specific surface area in the above range, a particle size of several μm to several tens of μm, several times to several tens of times larger than silica fume, and a large bulk density. It has good properties, does not agglomerate in the concrete composition, has excellent dispersibility and is easy to knead, and a highly fluid concrete composition can be obtained.
For example, such synthetic spherical silicon dioxide fine powder is commercially available under the trade names Admafine SO-E3, SO-E5, SO-E6, SO-C3, SO-C5, and SO-C6 manufactured by Admatechs. be able to.

  Further, the shape of the synthetic spherical silicon fine powder is a true sphere, an ellipse, or a spherical shape that is slightly distorted and uneven, and is included in the “spherical shape” in the present invention.

The special silica fine powder as the component (B2) is a powder composed of fine particles containing silicon dioxide (SiO ₂ ) as a main component and containing zirconia (zirconium oxide, ZrO ₂ ).
The content of silicon dioxide in the special siliceous fine powder is 91 to 95% by mass, and the content of zirconia is 3 to 5% by mass.
Moreover, the specific surface area of this special silica fine powder is 1-20 m < ² > / g. By using the special silica fine powder having such a composition, the fluidity of mortar and concrete can be improved, and good moldability can be obtained.
Here, the BET specific surface area is measured by the “nitrogen adsorption method”.
Examples of such special siliceous fine powder include zirconia-derived siliceous fine powder produced as a by-product when producing electrolytic zirconia.
As the special siliceous fine powder, SF-SILICAFUME manufactured by Sakai Industry Co., Ltd. can be obtained and used on the market.

  Such (B1) spherical silicon dioxide fine powder and (B2) special silica fine powder (1) have a large particle size compared to silica fume, and therefore have a low degree of aggregation and excellent dispersibility. It can be used in large quantities even at a cement ratio, (2) high sphericity, excellent fluidity and low viscosity, and (3) even if used in large quantities with little impurities, it adversely affects the properties of concrete. It is possible to produce a high-strength concrete panel product that has the characteristics such as absence and excellent instant moldability.

  The content of the synthetic spherical silicon dioxide fine powder of the component (B1) or the special silica part powder of the component (B2) in the concrete composition is the workability, compaction, and surface finish required for pressure vibration molding. In view of properties and strength, the content of the component (B1) or the component (B2) is 10 to 40 parts by mass, preferably 20 to 30 parts by mass with respect to 100 parts by mass of the (A) cement component.

In the concrete composition, the aggregate used as the component (C) includes a fine aggregate and a coarse aggregate. Examples of the fine aggregate include mountain sand used in ordinary mortar and concrete, Land sand, sea sand, river sand, crushed sand, blast furnace slag fine aggregate, ferronickel slag fine aggregate, copper slag fine aggregate, electric furnace oxidation slag, and the like.
The fine aggregate preferably has a fine particle amount of 5% by mass or less, preferably 3% by mass or less, as determined by the method of JIS A 1103 “Aggregate Fine Particle Amount Test Method”. Can be used.
Moreover, as a coarse aggregate, river gravel, mountain gravel, land gravel, sea gravel, crushed stone, blast furnace slag coarse aggregate, electric furnace oxidation slag, etc. can be used, for example.
It is desirable to select the fine aggregate and the coarse aggregate to be used that have a quality satisfying a compressive strength of 200 N / mm ² .
The aggregate (C) preferably has a particle size of 3 mm or more and 20 mm or less from the viewpoint of fluidity improvement, moldability, shrinkage reduction, and kneading performance.

Furthermore, in the said concrete compound, arbitrary fibers, such as steel fiber, a synthetic fiber, a natural fiber, can be used as a fiber used as (D) component.
Examples of the synthetic fiber include vinyl chloride, nylon, polyamide, polyester, polyurethane, vinylon, polyethylene, aramid fiber, and carbon fiber.
These fibers can be used in any length, but those having a length of preferably 1 mm to 20 mm are preferable, and those having a length of 2 mm to 10 mm are further improved in dispersibility, bending toughness, and cracks. Desirable in terms of suppression. The fiber diameter is preferably 0.001 mm to 2 mm.
The said fiber is mix | blended 1-5 volume% in a concrete compound. If it is less than 1% by volume, the reinforcing effect is not so great. If it exceeds 5% by volume, the compaction property of the concrete is remarkably lowered and the strength is lowered.
Examples of synthetic fibers available on the market include “Polypropylene microfiber” manufactured by Grace Chemicals, Kuraray vinylon fiber “Kratec”, “Powerlon”, and the like.

Furthermore, the concrete composition may contain a water reducing agent as the component (E) as necessary.
Examples of the water reducing agent include a high performance water reducing agent and a high performance AE water reducing agent that is a polycarboxylate-based water reducing agent. A general water reducing agent such as lignin sulfonate having a small water reducing rate has an effect of improving fluidity. Is difficult to obtain.
The high-performance water reducing agent is mainly composed of either a polyalkylallyl sulfonate system or a melamine formalin resin sulfonate system.

For example, polyalkylallyl sulfonate-based high-performance water reducing agents include methyl naphthalene sulfonic acid formalin condensate, naphthalene sulfonic acid formalin condensate, anthracene sulfonic acid formalin condensate, and the like. Trade name “FT-500” and its series, product names “Mighty-100 (powder)” and “Mighty-150” and its series, manufactured by Kao Corporation, Daiichi Kogyo Seiyaku Co., Ltd. Product name "Selflow 110P (powder)", Takemoto Oil & Fats Co., Ltd. product name "Pole Fine 510N", etc. Floric Co., Ltd. product name "Sunflow PS" and its series, Floric Co., Ltd. A typical product is the aromatic amino sulfonate-based high-performance water reducing agent of the product name “Palic FP200H” series.
The melamine formalin resin sulfonate-based high-performance water reducing agent includes Grace Chemicals' product name “FT-3S”, Showa Denko Co., Ltd. product names “Molmaster F-10 (powder)” and “Molmaster F”. -20 (powder) ".

In addition, as the polycarboxylate-based high-performance AE water reducing agent, the product name “Leo Build SP8” series manufactured by BASF Pozzolith Co., Ltd., the product name “Floric SF500” series manufactured by Floric Co., Ltd., Takemoto Yushi Co., Ltd. ) Product name “Chupol HP8,11” series manufactured by company, product name “Darlex Super 100, 200, 300, 1000” series manufactured by Grace Chemicals Co., Ltd., “Mighty 21WH, 3000S” manufactured by Kao Corporation, etc. Can be obtained and used on the market.
The blending amount of the high performance water reducing agent or the high performance AE water reducing agent is usually 1.0 to 2.5 mass with respect to a total of 100 mass parts of the component (A) and the component (B1) or (B2). It is desirable that it is about a part.

Moreover, the said expansion | swelling material can be added to the said concrete compound in the quantity generally used as (F) component as needed.
Furthermore, an inorganic admixture can be mix | blended with the said concrete compound as needed. As the inorganic admixture, known materials such as fine powder of blast furnace slag, fine powder of limestone, fly ash and the like can be used, but as the particle size, fine powder having a specific surface area of 2000 to 10000 cm ² / g is used. Is preferable from the viewpoint of the effect of reducing the necessary amount of the admixture.
This is because the blending amount is 15 to 40 parts by mass with respect to 100 parts by mass of (A) cement, and if the blending is in this range, the strength and fluidity are not adversely affected.

Moreover, although the concrete composition contains water, the mass ratio of water / [(A) component and (B1) component or (B2) component]] is 0.16 to 0.28, and It mix | blends so that unit water amount may be 100-175 kg / m < ³ >. Moreover, when an expansion | swelling material is mix | blended as needed, water / [(A) component, (B1) component or (B2) component, and the sum total of an expansion | swelling material)] mass ratio is 0.16- It is desirable to be 0.28.
By making the amount of water blended in such a small amount within the above range, a high-strength product having a high self-supporting property without losing its shape even after immediate demolding and having good moldability can be obtained. .

Next, a method for producing a concrete panel molded body using a concrete blend obtained by blending the above materials will be described.
The concrete panel molded body of the present invention comprises (A) cement, (B1) synthetic spherical silicon dioxide fine powder or (B2) special siliceous fine powder containing silicon oxide as a main component, (C) aggregate, D) Fiber and water are added, and the component (B1) has a silicon dioxide content of 99% by mass or more, an ignition loss at 1000 ± 50 ° C. of 0.3% by mass or less, and a BET specific surface area of 1 4.8 m ² / g, the component (B2) contains 91 to 95% by mass of silicon dioxide and 3 to 5% by mass of zirconia, has a BET specific surface area of 1 to ²⁰ m ² / g, and (A) The component (B1) or the component (B2) is blended so that the content of the component (B1) or the component (B2) is 10 to 30 parts by mass with respect to 100 parts by mass of the component. The combination of component A) with component (B1) or component (B2) ] Mass ratio is formulated as and unit water is 0.16 to 0.28 is 100~175kg / ^{m 3,} the concrete mix was prepared by uniformly kneading, the concrete mix prepared Is put into a panel form, molded by compaction by pressure vibration, and then immediately demolded and cured.

  Further, as described above, (E) a water reducing agent, (F) an expanding material, and the like can be added as necessary when preparing the concrete blend.

That is, the above-mentioned material components used in the concrete blend used for the production of the immediate demolding concrete product of the present invention, the uniaxial or biaxial forced kneading pug mill type mixer, the forced kneading pan type with the above-mentioned prescribed ratio of blending The concrete composition is prepared by kneading using a mixer or a tiltable mixer.
Subsequently, this concrete compound is put into a concrete panel form having a desired shape and molded.
At the time of molding, a pressure vibration molding process is added. Thereby, the filling property of the obtained concrete panel molded body becomes better, it is densified, cracks and warpage do not occur, and it is more effective.
The pressure vibration molding process depends on the output of the machine used and the frequency, but the applied pressure is 0.04 to 0.49 MPa, the frequency is 47 to 108 Hz, the amplitude is 0.3 to 2.5 mm, and the vibration time is The maximum acceleration is about 41 to 442 m / s ^{2 for 1} to 60 s.

The concrete composition subjected to the pressure vibration molding treatment is immediately demolded from the panel formwork.
The curing method is not particularly limited, and any method can be applied as long as it is a normal concrete curing method. For example, steam curing is preferably applied. As specific curing conditions, after curing for about 2 to 6 hours at room temperature, the temperature is increased to about 60 to 80 ° C. at a rate of temperature increase of about 10 to 30 ° C. per hour and about 2 to 6 hours. The method of hold | maintaining and then naturally cooling can be illustrated.

The present invention will be illustrated by the following examples and comparative examples, but is not limited thereto.
(Materials used)
・ Cement C: Ordinary Portland cement (manufactured by Sumitomo Osaka Cement Co., Ltd.)
Density 3.15 g / cm ³
-Fine aggregate S: mountain sand (produced in Kakegawa, Shizuoka Prefecture) density 2.58 g / cm ³
Coarse aggregate G: crushed stone (Okutama, Nishitama-gun) density 2.64 g / cm ³
・ Expansion material: Brand name Saks (manufactured by Sumitomo Osaka Cement Co., Ltd.) Density 2.93 g / cm ³
・ Fiber: Polypropylene microfiber (Grace Chemicals)
・ Water W: Tap water ・ High-performance water reducing agent: SP (Tupol SSP-104) Takemoto Yushi Co., Ltd. ・ Special siliceous fine powder ZSF: Trade name SP-SILICA FUME (Sakai Industry Co., Ltd.)
Density 2.25 g / cm ³
Synthetic spherical silicon dioxide powder (spherical silica): shown in Table 1 below.
Table 1 below shows the composition and BET specific surface area of the special siliceous powder and the synthetic spherical silicon dioxide powder. For comparison, the composition of ordinary silica fume is also shown.

In Table 1 above, the content of silicon dioxide is the Cement Association method “chemical analysis method of siliceous raw materials”, and the content of SO ₃ (sulfur trioxide) and MgO is JIS R 5202 “chemical analysis method of Portland cement” The ZrO ₂ content was measured using a wavelength dispersive X-ray fluorescence apparatus (semi-quantitative analysis by a powder method). The ignition loss was measured at 1000 ± 50 ° C. according to JIS A 6201 “Fly Ash for Concrete”. Further, as an index of the amount of unburned carbon (unburned carbon), the amount of methylene blue adsorbed was measured according to the “Methylene Blue Adsorbed Amount Test” of the Cement Association Method. The BET specific surface area was measured by the “nitrogen adsorption method”.
When observed at a magnification of 5,000 to 50,000 times using a FE-SEM (field emission scanning electron microscope), the synthetic spherical silicon dioxide powder and the special siliceous fine powder have a particle size of about 0.5 to 50 μm. Spherical primary particles were hardly aggregated.

Further, from Table 1, the synthetic spherical silicon dioxide powder and the special siliceous fine powder have a silicon dioxide content equal to or higher than that of silica fume, and the contents of impurities SO ₃ and MgO are extremely low. In addition, the synthetic spherical silicon dioxide powder and the special siliceous fine powder are judged to have less unburned carbon (unburned carbon) because the ignition loss and methylene blue adsorption amount are remarkably less than silica fume. Moreover, it turns out that a synthetic | combination spherical silicon dioxide powder and special siliceous fine powder are significantly smaller than a silica fume in a BET specific surface area.

(Examples 1-13, Comparative Examples 1-4)
Using each of the above materials, each concrete blend having the blend composition shown in Table 2 was prepared.
Specifically, cement (C), fine aggregate (S), coarse aggregate (G), synthetic spherical silicon dioxide powder (spherical silica), special siliceous fine powder (ZSF), expansion material, fiber, high performance A water reducing agent (SP) is put into a biaxial forced kneading mixer at a ratio shown in Table 2, and after stirring for 30 seconds, tap water (kneading water) is water / [cement + synthetic spherical silicon dioxide powder or special siliceous powder. The mass ratio of 0.16 to 0.28 and the unit water amount to 100 to 175 kg / m ³ were further added at the blending amounts shown in Table 2 and mixed for 3 minutes to prepare each concrete blend.

In order to produce a concrete panel having a size of 100 cm × 100 cm × thickness 2 cm as a formwork, the concrete compositions of Examples 1 to 13 and Comparative Examples 1 to 4 were used by using a formwork of 100 cm × 100 cm × height 5 cm. Each concrete panel specimen was manufactured using this method.
Since Comparative Examples 1 to 3 are self-filling type mortars excellent in fluidity, each concrete composition is charged directly into the panel formwork so as to have a thickness of 2 cm, without particularly giving vibration or the like. Each concrete panel was manufactured.
Since Comparative Example 4 and Examples 1 to 13 are kneaded mortars, the mass that theoretically becomes a height of 2 cm with a porosity of 0% is measured, and the amount corresponding to the mass is introduced into the mold. Then, compaction was performed using a plate runner (EVC40A) manufactured by EXEN, and each concrete panel was created.

The concrete panel molded bodies of the above Examples 1 to 13 and Comparative Examples 1 to 4 were each subjected to the following steam curing to obtain each concrete panel molded body.
Steam curing: pre-curing for 4 hours (room temperature), heating at 20 ° C./hour, holding at 70 ° C. for 4 hours, and then naturally cooling.

(Test example)
Test example 1
Formability In evaluating the formability of each obtained concrete panel molded body, concrete test bodies were prepared by the following method using the concrete mixtures of Examples 1 to 13 and Comparative Example 4 in Table 2 above. evaluated.
In addition, since Comparative Examples 1-3 were concrete which has self-filling property, it cast and shape | molded.
As a formwork, a concrete strength test form having an inner diameter of 10 cm and a height of 20 cm was used, and each of the above concrete compositions was put into the formwork. The amount to be added was measured by measuring the mass of 10 cm in height with a theoretical porosity of 0%, and the amount corresponding to the mass was added.

  Subsequently, pressure vibration was added to the concrete composition in the mold by using the one accompanying the marshalling test runner described in JP-A-2005-241371. Since each concrete composition is tamped through the pressing plate and pressed down by 40 compactions, the distance A from the upper end of the formwork to the upper surface of the concrete was measured by removing the rammer.

In this way, if the distance A from the upper end of the formwork to the top surface of the concrete is measured, the concrete height B in the formwork can be obtained by subtracting from the height of the formwork, and the maximum compaction height By dividing 10 cm by the height B, the concrete filling rate (consolidation degree) when a heavy object was dropped at a certain number of times was determined.
Formability was evaluated by the filling rate of each concrete specimen prepared with each of the above marshall rammers.
○: Filling rate 95% or more, Δ: Filling rate 90 to 95% or more, ×: Filling rate 90% or less

Test example 2
The compressive strength of the concrete panels obtained in Examples 1 to 13 and Comparative Examples 1 to 4 was evaluated.
Compressive strength The compressive strength is a value measured according to JIS A 1108.
The concrete specimen subjected to steam curing is one day old, and the concrete specimen subjected to accelerated curing is a compressive strength test using each concrete specimen subjected to hot water curing for 7 days after steam curing. Carried out.

Mortar flow The mortar flow value is determined by placing a cylindrical container of φ5 × 10 cm on a horizontal glass plate, and pouring the prepared mortars of Comparative Examples 1 to 3 into the top so that the cylindrical shape is filled. This was a value obtained by gently lifting the container vertically and measuring the flow value spread most widely on the glass plate and the flow value in the direction perpendicular thereto.

Cracks Cracks were measured and evaluated with a crack scale (manufactured by Shinwa Measurement Co., Ltd.).
◎: No, ○: 1m ² per 0.06mm or less of cracks three following occurrence △: The following cracks 1m ² per 0.06mm is four or more generated ×: width 0.10mm or more of crack occurrence.

Degree of warpage Each concrete panel was placed on a horizontal surface, and the degree of warpage of each panel was measured with a ruler and evaluated.
○: Less than 3 mm, Δ3 mm or more to less than 5 mm, × 5 mm or more

From Table 3, the concrete panels of Comparative Examples 1 to 3 obtained a high strength of 150 N / mm ² or more in terms of strength, but manufactured a panel with a thickness of 2 cm × 1 m square and exposed to the outside for one month. As a result of the test, cracks and warpage occurred in Comparative Examples 1 to 3. It turns out that there is a problem as a large panel material.
Moreover, Examples 1-13 obtained high intensity | strength with respect to the mixing | blending of the plain of the comparative example 4, and also about Example 13, generation | occurrence | production of a micro hair crack was not recognized at all by addition of an expansion material, and Example 2 was used. About -5 and 7-13, it turns out that generation | occurrence | production of the warp was not recognized by the outdoor exposure test of the panel.

  The concrete panel molded body of the present invention can be applied to concrete panels that are inexpensive and mass-consumed in the field of construction and civil engineering, such as repairs for waterways.

Claims (4)

(A) cement, (B1) synthetic spherical silicon dioxide fine powder or (B2) special siliceous fine powder containing silicon oxide as a main component and containing zirconium oxide, (C) aggregate, (D) concrete blend containing fiber and water A concrete panel formed by pressure vibration molding of an object, wherein the component (B1) has a silicon dioxide content of 99% by mass or more, an ignition loss at 1000 ± 50 ° C. of 0.3% by mass or less, and The BET specific surface area is 1 to 4.8 m ² / g, the component (B2) contains 91 to 95% by mass of silicon dioxide and 3 to 5% by mass of zirconia, and the BET specific surface area is 1 to ²⁰ m ² / g. Yes, in the concrete composition, with respect to 100 parts by mass of component (A), the content of component (B1) or (B2) is 10 to 40 parts by mass, water / [(A) component, and (B1) Component or (B2) combined with component ] And unit water mass ratio is from 0.16 to 0.28 is 100~175kg / ^{m 3,} characterized in that it contains 1-5 volume% component (D), concrete panels molded body.   The concrete panel molded body according to claim 1, further comprising (E) a water reducing agent and / or (F) an expansion material. (A) cement, (B1) synthetic spherical silicon dioxide fine powder or (B2) special siliceous fine powder mainly containing silicon dioxide and containing zirconium oxide, (C) aggregate, (D) fibers and water, The component (B1) has a silicon dioxide content of 99% by mass or more, an ignition loss at 1000 ± 50 ° C. of 0.3% by mass or less, and a BET specific surface area of 1 to 4.8 m ² / g. The component (B2) contains 91 to 95% by mass of silicon dioxide and 3 to 5% by mass of zirconia, has a BET specific surface area of 1 to ²⁰ m ² / g, and (B1) with respect to 100 parts by mass of the component (A) (B1) component or (B2) component is mix | blended so that content of a component or (B2) component may be 10-40 mass parts, and also water / [(A) component and (B1) component or (Total with (B2) component] The mass ratio is 0.16 to 0.28 and the unit The amount is formulated so as to 100~175kg / m ^3, the concrete mix was prepared by uniformly kneading, it was charged the concrete mix prepared in the panel formwork, compaction by pressure vibration A method for producing a concrete panel molded body, characterized in that it is demolded immediately after being molded and subjected to curing treatment.   4. The method for producing a concrete panel molded body according to claim 3, wherein (E) a water reducing agent and / or (F) an expanding material is further added.