JP2005082470A - Concrete board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete board capable of holding a harmony with the surrounding landscape over a long period and used for the construction of a hydraulic structure such as a sediment control dam or river revetment. <P>SOLUTION: The concrete board comprises a hardened body of a composition containing at least cement, pozzolan fine powder, fine aggregate having ≤2 mm particle diameter, a water reducing agent and water and has a pseudo rock pattern on the surface. The concrete board has a surface where a natural stone is exposed and the concrete comprises a hardened body of a composition containing at least the cement, the pozzolan fine powder, the fine aggregate having ≤2 mm particle diameter, the water reducing agent and water. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a concrete plate used for construction and repair of hydraulic structures such as sabo dams and river revetments.

In recent years, in the construction of hydraulic structures such as sabo dams and river revetments, in addition to saving labor and shortening the construction period, maintaining the scenery around the construction site has become an important issue. Therefore, in the construction of sabo dams, etc., in order to harmonize with the scenery around the construction site, a large number of pseudo stones protrude from the surface of the main plate such as hexagons and rectangles, and the main plate is connected to the center of the back via a connecting part. It has been proposed to use a building block provided with a locking part with a slanted top and bottom of the connecting part formed in a vertical direction with respect to the construction of a sabo dam (patent) Reference 1).
JP-A-9-151439

Since the building block described in Patent Document 1 is a building block that also functions as a self-supporting formwork, it can be constructed by stacking the blocks and placing concrete in the interior. In addition, it is possible to achieve harmony with the scenery around the construction site by projecting many pseudo stones on the surface.
However, the building block described in Patent Document 1 has low wear resistance such as a pseudo-stone part, so when it is used for construction of hydraulic structures such as sabo dam overflows, paddles, river revetments, etc. There is a problem that it is difficult to maintain an excellent landscape for a long period of time.

  As a result of diligent research to solve the above-mentioned problems, the present inventor has found a concrete plate made of a hardened body of a compound containing a specific material and having a pseudo-rock pattern on the surface, or a specific material with natural stone exposed on the surface. If it is a concrete board consisting of a hardened body of a composition containing it, it is possible to construct hydraulic structures such as sabo dams and river revetments that can maintain harmony with the surrounding landscape over a long period of time. The present invention has been completed by finding that labor can be saved and the construction period can be shortened in the construction and repair work of hydraulic structures such as dams and river revetments.

That is, the present invention is a concrete plate comprising a hardened body of a composition containing at least cement, pozzolanic fine powder, fine aggregate having a particle size of 2 mm or less, a water reducing agent, and water, and has a pseudo-rock pattern on the surface. A concrete board characterized in that (Claim 1).
The present invention also relates to a concrete plate having a natural stone exposed on the surface, wherein the concrete comprises at least a cement, a pozzolanic fine powder, a fine aggregate having a particle size of 2 mm or less, a water reducing agent, and water. A concrete board comprising a hardened body (claim 2).
The concrete board may contain inorganic particles having a Blaine specific surface area of 2500 to 30000 cm ² / g and having a Blaine specific surface area larger than that of the cement.
The inorganic particles may be composed of inorganic particles A of Blaine specific surface area 5000~30000cm ² / g, the Blaine specific surface area 2500~5000cm ² / g and inorganic particles B (claim 4).
The said concrete board can contain the 1 or more types of fiber chosen from the group which consists of a metal fiber, an organic fiber, and a carbon fiber in a compound (Claim 5).

Since the concrete board of the present invention is made of a cured body that exhibits a compressive strength of 120 MPa or more and a bending strength of 20 MPa or more, the thickness can be reduced and the weight can be reduced. Therefore, it is easy to handle when used for construction and repair of hydraulic structures such as sabo dams and river revetments.
Moreover, since the concrete board of this invention can be used as a buried formwork in construction of hydraulic structures, such as a sabo dam and a river revetment, it can aim at labor saving of a construction and shortening of a construction period.
In addition, the concrete board of the present invention has a hydraulic structure such as a sabo dam or river revetment that has a pseudo-rock pattern on the surface, or natural stone is exposed on the surface, so that it can be harmonized with the scenery around the construction site. Can be built. Furthermore, since the concrete board of this invention is excellent also in abrasion resistance, it can construct hydraulic structures, such as a sabo dam and a river revetment, which can maintain harmony with the surrounding scenery over a long period of time.
Moreover, since the concrete board of this invention is manufactured using the compound excellent in fluidity | liquidity, the manufacture (especially shaping | molding) is easy.

Hereinafter, the present invention will be described in detail.
Examples of the cement used in the present invention include various Portland cements such as ordinary Portland cement, early-strength Portland cement, medium heat Portland cement, and low heat Portland cement.
In the present invention, when trying to improve the early strength of the concrete board, it is preferable to use early-strength Portland cement, and when trying to improve the fluidity of the blend, It is preferred to use low heat Portland cement.

Blaine specific surface area of the cement, preferably ^{2500~5000cm 2 / g, 3000~4500cm 2 /} g is more preferable. If the value is less than 2500 cm ² / g, the hydration reaction becomes inactive and the strength of the concrete plate is reduced. If it exceeds 5000 cm ² / g, it takes time to grind the cement. Moreover, since the amount of water for obtaining a predetermined fluidity increases, there are disadvantages such as a large dimensional change of the concrete board.

Examples of the pozzolanic fine powder include silica fume, silica dust, fly ash, slag, volcanic ash, silica sol, and precipitated silica.
In general, silica fume and silica dust have a BET specific surface area of 5 to 25 m ² / g and do not need to be pulverized, and thus are suitable as the pozzolanic fine powder of the present invention.
BET specific surface area of the pozzolanic substance fine powder is preferably ^{5~25m 2 / g, 8~25m 2 /} g is more preferable. When the value is less than 5 m ² / g, there are disadvantages such as a decrease in the strength of the concrete plate. When the value exceeds 25 m ² / g, the amount of water for obtaining a predetermined fluidity increases, There are drawbacks such as reduced strength.
The blending amount of the pozzolanic fine powder is 5 to 50 parts by mass, preferably 10 to 40 parts by mass with respect to 100 parts by mass of cement. When the blending amount is out of the range of 5 to 50 parts by mass, the fluidity is extremely lowered, so that there is a drawback that it takes time to manufacture the concrete plate.

In the present invention, a fine aggregate having a particle size of 2 mm or less is used. Here, the particle size of the fine aggregate is an 85% mass cumulative particle size. When the particle size of the fine aggregate exceeds 2 mm, the strength and the like of the concrete plate are lowered, which is not preferable.
In the present invention, it is preferable to use a fine aggregate having a maximum particle size of 2 mm or less, and more preferably a fine aggregate having a maximum particle size of 1.5 mm or less in view of the strength of the concrete board. From the viewpoint of fluidity of the blend, it is preferable to use a fine aggregate having a particle content of 75 μm or less of 2.0% by mass or less, and a fine aggregate having a particle content of 75 μm or less of 1.5% by mass or less. It is more preferable to use
As the fine aggregate, river sand, land sand, sea sand, crushed sand, silica sand and the like, or a mixture thereof can be used.
The blending amount of the fine aggregate is preferably 50 to 250 parts by weight, preferably 80 to 200 parts by weight with respect to 100 parts by weight of cement, from the viewpoint of the fluidity of the blend and the strength of the concrete board. More preferred.

As the water reducing agent, a lignin-based, naphthalenesulfonic acid-based, melamine-based, or polycarboxylic acid-based water reducing agent, an AE water reducing agent, a high-performance water reducing agent, or a high-performance AE water reducing agent can be used. Among these, it is preferable to use a high performance water reducing agent or a high performance AE water reducing agent having a large water reducing effect, and it is particularly preferable to use a polycarboxylic acid-based high performance water reducing agent or a high performance AE water reducing agent.
The blending amount of the water reducing agent is preferably 0.1 to 4.0 parts by mass, more preferably 0.1 to 2.0 parts by mass in terms of solid content with respect to 100 parts by mass of cement. If the blending amount is less than 0.1 parts by mass, kneading becomes difficult, fluidity is lowered, and it takes time to produce a concrete plate. If the blending amount exceeds 4.0 parts by mass, material separation and significant setting delay occur, and the strength and the like of the concrete plate may decrease.
The water reducing agent can be used in a liquid or powder form.

  The amount of water is preferably 10 to 30 parts by mass, more preferably 12 to 25 parts by mass with respect to 100 parts by mass of cement. If the amount of water is less than 10 parts by mass, kneading becomes difficult, fluidity is lowered, and it takes time to produce a concrete plate. If the amount of water exceeds 30 parts by mass, the strength and the like of the concrete plate will decrease.

In the present invention, from the viewpoint of improving the fluidity of the blend, the strength development and durability of the cured body, the blend has a brane specific surface area of 2500 to 30000 cm ² / g and a brane larger than the cement. It is preferable to include inorganic particles having a specific surface area.
Examples of the inorganic particles include slag, limestone powder, feldspar, mullite, alumina powder, quartz powder, fly ash, volcanic ash, silica sol, carbide powder, and nitride powder. Among these, slag, limestone powder, and quartz powder are preferably used in terms of cost and quality stability after curing.
Inorganic particles, Blaine specific surface area of preferably 2500~30000cm ² / g, more preferably at 4500~20000cm ² / g, and has a large Blaine specific surface area than the cement particles. If the specific surface area of the inorganic particles is less than 2500 cm ² / g, the difference in the specific surface area of the brane with the cement will be small, making it difficult to ensure high fluidity (self-filling). There are drawbacks such as taking time, and if it exceeds 30000 cm ² / g, it takes time to grind, making it difficult to obtain materials, and it becomes difficult to obtain the prescribed fluidity, so it takes time to manufacture concrete plates, etc. There are disadvantages.

The inorganic particles have a larger Blaine specific surface area than cement, so that the inorganic particles have a particle size that fills the gap between the cement and the pozzolanic fine powder, ensuring high fluidity (self-filling) and the like. Can do.
The difference in the Blaine specific surface area between the inorganic particles and the cement is preferably 1000 cm ² / g or more, more preferably 2000 cm ² / g or more, from the viewpoints of fluidity before curing and strength development after curing.
The blending amount of the inorganic particles is preferably 55 parts by mass or less, more preferably 10 to 50 parts by mass with respect to 100 parts by mass of cement.

In the present invention, two different kinds of inorganic particles A and inorganic particles B can be used in combination as the inorganic particles.
In this case, the inorganic particles A and the inorganic particles B may use the same type of powder (for example, limestone powder) or different types of powder (for example, limestone powder and quartz powder).
The inorganic particles A have a brain specific surface area of 5000 to 30000 cm ² / g, preferably 6000 to 20000 cm ² / g. In addition, the inorganic particles A have a larger Blaine specific surface area than the cement and the inorganic particles B.
If the Blaine specific surface area of the inorganic particles A is less than 5000 cm ² / g, the difference in the Blaine specific surface area with the cement or the inorganic particles B becomes smaller, and the fluidity and the like than when using the above-mentioned one kind of inorganic particles. Not only is the effect of improving the resistance small, but since two kinds of inorganic particles are used, it takes time to prepare the material, which is not preferable. When the specific surface area of the branes exceeds 30000 cm ² / g, it takes time to grind, so it is difficult to obtain the material, and it is difficult to obtain a predetermined fluidity. is there.

In addition, the inorganic particles A have a grain size that fills the gap between the cement and the inorganic particles B and the pozzolanic fine powder because the inorganic particles A have a larger Blaine specific surface area than the cement and the inorganic particles B. Thus, more excellent fluidity and the like can be ensured.
The difference in the specific surface area of the branes between the inorganic particles A and the cement and the inorganic particles B (in other words, the difference in the specific surface area of the inorganic particles A and the larger one of the cement and the inorganic particles B). From the viewpoint of the fluidity of the product and the strength development of the cured product, it is preferably 1000 cm ² / g or more, more preferably 2000 cm ² / g or more.

The Blaine specific surface area of the inorganic particles B is 2500 to 5000 cm ² / g. The difference between the Blaine specific surface area of the cement and the inorganic particles B is preferably at least 100 cm ² / g, from the viewpoint of strength development of the fluidity and curing of the formulation, 200 cm ² / g or more is more preferable.
If the Blaine specific surface area of the inorganic particles B is less than 2500 cm ² / g, the fluidity decreases and it becomes difficult to obtain self-filling properties, so there is a drawback that it takes time to manufacture the concrete plate, and 5000 cm ² / g When the value exceeds 1, the numerical value of the Blaine specific surface area approaches that of the inorganic particles A, so that the effect of improving the fluidity and the like is reduced as compared with the case of using the one kind of inorganic particles. Since it is used, it takes time to prepare the material, which is not preferable.
Further, when the difference in the Blaine specific surface area between the cement and the inorganic particles B is 100 cm ² / g or more, the filling property of the particles constituting the compound is improved, and more excellent fluidity and the like can be secured. .

The compounding amount of the inorganic particles A is preferably 10 to 50 parts by mass and more preferably 15 to 40 parts by mass with respect to 100 parts by mass of cement. The blending amount of the inorganic particles B is preferably 5 to 35 parts by mass, more preferably 10 to 30 parts by mass with respect to 100 parts by mass of cement. When the blending amount of the inorganic particles A and the inorganic particles B is out of the above numerical range, the effect of improving fluidity and the like is reduced as compared with the case where the one kind of inorganic particles is used, and two kinds of inorganic particles are used. This is not preferable because it takes time to prepare the material.
In addition, 55 mass parts or less are preferable with respect to 100 mass parts of cement, and, as for the total amount of the inorganic particle A and the inorganic particle B, More preferably, it is 10-50 mass parts.

In the present invention, from the viewpoint of greatly increasing the bending strength, breaking strength, etc. of the cured body, it is preferable to blend one or more fibers selected from the group consisting of metal fibers, organic fibers and carbon fibers into the blend. .
The metal fiber is blended from the viewpoint of greatly increasing the bending strength and the like of the cured body.
Examples of metal fibers include steel fibers, stainless fibers, and amorphous fibers. Among these, steel fibers are excellent in strength and are preferable from the viewpoint of cost and availability. The size of the metal fiber is preferably 0.01 to 1.0 mm in diameter and 2 to 30 mm in length from the viewpoint of preventing material separation of the metal fiber in the composition and improving the bending strength of the cured body. Is more preferably 0.05 to 0.5 mm and the length is 5 to 25 mm. The aspect ratio (fiber length / fiber diameter) of the metal fiber is preferably 20 to 200, more preferably 40 to 150.

The shape of the metal fiber is preferably a shape that imparts some physical adhesion (for example, a spiral shape or a waveform) rather than a straight shape. If it is in a spiral shape or the like, the stress is secured while the metal fibers and the matrix are pulled out, so that the bending strength is improved.
Preferable examples of metal fibers include, for example, an interfacial adhesion strength (adhesion) to a matrix of a cementitious hardened body made of steel fibers having a diameter of 0.5 mm or less and a tensile strength of 1 to 3.5 GPa and having a compressive strength of 120 MPa. The maximum tensile force per unit area of the surface is 3 MPa or more. In this example, the metal fiber can be processed into a corrugated or helical shape. Moreover, the groove | channel or processus | protrusion for resisting the motion (longitudinal slip) with respect to a matrix can also be attached on the surrounding surface of the metal fiber of this example. The metal fiber of this example has a metal layer having a Young's modulus smaller than the Young's modulus of the steel fiber on the surface of the steel fiber (for example, one or more selected from zinc, tin, copper, aluminum, etc.) It is good also as what provided.

  The blending amount of the metal fiber is preferably 6% or less, more preferably 0.5 to 5%, and particularly preferably 1 to 4% in terms of volume percentage in the blend. If the blending amount exceeds 6%, many fibers are exposed on the surface of the concrete plate and the surface properties are remarkably deteriorated. Also, so-called fiber balls are easily formed during kneading, which is not preferable.

The organic fiber and the carbon fiber are blended from the viewpoint of increasing the breaking energy of the cured body.
Examples of the organic fiber include vinylon fiber, polypropylene fiber, polyethylene fiber, and aramid fiber. Among these, vinylon fibers and / or polypropylene fibers are preferably used in terms of cost and availability.
Examples of the carbon fiber include PAN-based carbon fiber and pitch-based carbon fiber.
The dimensions of the organic fibers and carbon fibers are preferably 0.005 to 1.0 mm in diameter and 2 to 30 mm in length from the viewpoint of preventing material separation of these fibers in the formulation and improving the fracture energy after curing. More preferably, the diameter is 0.01 to 0.5 mm and the length is 5 to 25 mm. Further, the aspect ratio (fiber length / fiber diameter) of the organic fiber and the carbon fiber is preferably 20 to 200, more preferably 30 to 150.

  The blending amount of the organic fiber and the carbon fiber is preferably 10% or less, more preferably 1 to 9%, and particularly preferably 2 to 8% by volume percentage in the blend. If the blending amount exceeds 10%, a large number of fibers are exposed on the surface of the concrete plate and the surface properties are remarkably deteriorated. Also, so-called fiber balls are easily formed during kneading, which is not preferable.

In the present invention, fibrous particles or flaky particles having an average particle size of 1 mm or less may be blended in the blend. By blending the fibrous particles or flaky particles, the toughness of the cured product can be increased. The particle size of the particle is the size of the maximum dimension (particularly, the length of the fibrous particle).
Examples of fibrous particles include wollastonite, bauxite, mullite, and examples of flaky particles include mica flakes, talc flakes, vermiculite flakes, and alumina flakes.
The blending amount of the fibrous particles or the flaky particles is preferably 35 parts by mass or less, more preferably 25 parts by mass or less with respect to 100 parts by mass of the cement, from the strength and toughness of the cured body.
In addition, it is preferable to use a fibrous particle having a needle-like degree represented by a ratio of length / diameter of 3 or more from the viewpoint of increasing the toughness of the cured body.

The kneading method of the blend is not particularly limited. For example, (1) materials other than water and a water reducing agent are mixed in advance to prepare a premix material, and the premix material, water and water reduction (2) Prepare a powdery water reducing agent, mix materials other than water in advance to prepare a premix material, and mix the premix material and water with the mixer. (3) A method in which each material is individually fed into a mixer and kneaded, etc. can be employed.
The mixer used for kneading may be of any type used for ordinary concrete kneading. For example, a rocking mixer, a pan type mixer, a biaxial kneading mixer, or the like is used.

A concrete plate having a pseudo-rock pattern on the surface is produced by pouring the kneaded mixture into a predetermined form and then curing it.
Concrete boards with exposed natural stone on the surface, for example, (1) after embedding a large number of natural stones at a depth sufficient to fix the natural stone on one side of the composition before curing, It can be produced by curing. Also, (2) a large number of natural stones are placed in the mold, and the compound is poured into the mold to be molded, and the compound is washed out before the compound is cured to expose the natural stone. it can.
The natural stones exposed on the surface are those whose physical properties are described in “JIS A 1121 (Coarse Aggregate Testing Method with Los Angeles Testing Machine)”, with a reduction in grinding amount of 35% or less, “JIS A 1110 (coarse Aggregate density and water absorption test method) ”, the absolute dry density is 2.5g / cm ³ or more, the water absorption is 3.0% or less, and the chemical properties are“ JIS A 5308 (Ready mixed concrete). In the method described in Annex 7 or 8, it is preferable to use natural stones whose alkali silica reactivity is determined to be harmless.
The concrete plate may be cured by steam curing, air curing, or the like.

The composition used in the present invention is a value measured in the method described in “JIS R 5201 (Cement physical test method) 11. Flow test” without performing 15 drop motions (in this specification, (Also referred to as “0 stroke flow value”) is excellent in fluidity of 230 mm or more and has self-filling properties, so that the production (particularly molding) of the concrete board can be performed easily.
Further, the cured body of the composition of the present invention expresses a compressive strength of 120 MPa or more and a bending strength of 20 MPa or more, and the concrete board of the present invention made of the cured body can be reduced in thickness. Can be reduced in weight.
Moreover, the hardened | cured material of the compound of this invention is excellent in abrasion resistance, and the concrete board of this invention which consists of this hardening body is also excellent in abrasion resistance.

The concrete board of the present invention can be used for construction and repair of hydraulic structures such as sabo dams and river revetments.
The concrete board of the present invention can also be used as a buried form in the construction of hydraulic structures such as sabo dams and river revetments. Therefore, hydraulic structures such as sabo dams and river revetments can be constructed by stacking the concrete plates of the present invention and placing concrete therein, so that labor savings and shortening of the construction period can be achieved.
In addition, the concrete board of the present invention has a pseudo-rock pattern on the surface or exposed natural stone on the surface, so that it can be harmonized with the scenery around the construction site, such as a sabo dam or river revetment. Can be built. Furthermore, since the concrete board of this invention is excellent also in abrasion resistance, hydraulic structures, such as a sabo dam and a river revetment which can maintain harmony with the surrounding scenery over a long period of time, can be constructed.

Hereinafter, the present invention will be described by way of examples.
[1. Materials used]
The following materials were used.
(1) Cement; Low heat Portland cement (manufactured by Taiheiyo Cement)
; Blaine specific surface area 3200cm ² / g)
(2) Pozzolanic fine powder; silica fume (BET specific surface area 10 m ² / g)
(3) Inorganic particles A; quartz powder A (Blaine specific surface area 7500 cm ² / g)
(4) Inorganic particles B; quartz powder B (Blaine specific surface area 4000 cm ² / g)
(5) Fine aggregate: silica sand (maximum particle size 0.6mm, content of particles less than 75μm 0.3% by mass)
(6) Metal fiber: Steel fiber (diameter: 0.2mm, length: 13mm)
(7) Water reducing agent; polycarboxylic acid-based high performance AE water reducing agent (8) Water; tap water

Example 1
Low heat Portland cement 100 parts by mass, silica fume 32 parts by mass, quartz powder A 39 parts by mass, silica sand 120 parts by mass, high performance AE water reducing agent 1.0 part by mass (solid content with respect to cement), water 22 parts by mass, Kneaded.
The flow value of the blend was measured in the method described in “JIS R 5201 (Cement physical test method) 11. Flow test” without performing 15 drop motions. As a result, the flow value was 265 mm.
Further, the blend was poured into a mold of φ50 × 100 mm, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The cured body had a compressive strength (average of 3) of 210 MPa.
The blend was poured into a 4 × 4 × 16 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The bending strength (average value of 3 pieces) of the cured product was 25 MPa.
The blend was poured into a 30 × 30 × 5 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The cured product was subjected to an abrasion resistance test. In the abrasion resistance test, the abrasion resistance was evaluated by the “ASTM C 779” method (slip depth test) and the “ASTM C 418” method (sand blast test). As a comparison, the wear resistance test of high strength concrete having a compressive strength of 70 MPa was also conducted. As a result, when the grinding depth of the cured product of the present invention was 100, it was 205 in the comparative example. When the sandblast test result of the cured product of the present invention was 100, it was 270 in the comparative example.

Example 2
Low heat Portland cement 100 parts by weight, silica fume 32 parts by weight, quartz powder A26 parts by weight, quartz powder B13 parts by weight, silica sand 120 parts by weight, high performance AE water reducing agent 1.0 part by weight (solid content with respect to cement), water 22 parts by weight It put into the shaft mixer and kneaded.
The flow value of the blend was measured in the method described in “JIS R 5201 (Cement physical test method) 11. Flow test” without performing 15 drop motions. As a result, the flow value was 285 mm.
Further, the blend was poured into a mold of φ50 × 100 mm, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The cured body had a compressive strength (average of 3) of 230 MPa.
The blend was poured into a 4 × 4 × 16 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The bending strength (average value of three pieces) of the cured body was 28 MPa.
The blend was poured into a 30 × 30 × 5 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The cured product was subjected to an abrasion resistance test. In the abrasion resistance test, the abrasion resistance was evaluated by the “ASTM C 779” method (slip depth test) and the “ASTM C 418” method (sand blast test). As a comparison, the wear resistance test of high-strength concrete having a compressive strength of 70 MPa was performed in the same manner. As a result, when the grinding depth of the cured product of the present invention was 100, it was 210 in the comparative example. When the sandblast test result of the cured product of the present invention was 100, it was 280 in the comparative example.

Example 3
Low heat Portland cement 100 parts by weight, silica fume 32 parts by weight, quartz powder A26 parts by weight, quartz powder B13 parts by weight, silica sand 120 parts by weight, high performance AE water reducing agent 1.0 part by weight (solid content with respect to cement), water 22 parts by weight, steel The fiber (2% of the volume in the formulation) was put into a biaxial mixer and kneaded.
The flow value of the blend was measured in the method described in “JIS R 5201 (Cement physical test method) 11. Flow test” without performing 15 drop motions. As a result, the flow value was 265 mm.
Further, the blend was poured into a mold of φ50 × 100 mm, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The cured body had a compressive strength (average of 3) of 210 MPa.
The blend was poured into a 4 × 4 × 16 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The bending strength (average value of 3 pieces) of the cured product was 47 MPa.
The blend was poured into a 30 × 30 × 5 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The cured product was subjected to an abrasion resistance test. In the abrasion resistance test, the abrasion resistance was evaluated by the “ASTM C 779” method (slip depth test) and the “ASTM C 418” method (sand blast test). As a comparison, the wear resistance test of high-strength concrete having a compressive strength of 70 MPa was performed in the same manner. As a result, when the depth of wear of the cured product of the present invention was 100, it was 215 in the comparative example. When the sandblast test result of the cured product of the present invention was 100, it was 285 in the comparative example.

Claims (5)

  A concrete plate comprising a hardened body of a composition containing at least cement, fine powder of pozzolana, fine aggregate having a particle diameter of 2 mm or less, a water reducing agent, and water, and having a pseudo-rock pattern on the surface Board.   It is a concrete plate with a natural stone exposed on the surface, and the concrete consists of a hardened body of a composition containing at least cement, pozzolanic fine powder, fine aggregate having a particle size of 2 mm or less, a water reducing agent, and water. A featured concrete board. The formulation, by Blaine specific surface area of 2500~30000cm ² / g, and according to claim 1 or 2 concrete slab according containing inorganic particles having a large Blaine specific surface area than the cement. Inorganic particles, and inorganic particles A of Blaine specific surface area 5000~30000cm ² / g, concrete board according to claim 3, wherein comprising an inorganic particles B of Blaine specific surface area 2500~5000cm ² / g.   The concrete board in any one of Claims 1-4 which contains 1 or more types of fiber chosen from the group which consists of a metal fiber, an organic fiber, and carbon fiber in a compound.