JP4298247B2 - High fluidity concrete - Google Patents

Description

【００３６】
［２．コンクリートの配合及び混練］
表１に示す配合の結合材及びその他の材料を使用して、表２に示す配合のコンクリートを調製した。混練は、２軸強制練りミキサ（0.1m³）を用いて、180秒間行なった。
【００３７】
【表１】

【００３８】
【表２】

【００３９】
［３．評価］
調製されたコンクリートの物性を次のようにして評価した。
（１）スランプフロー
「JIS A 1150（コンクリートのスランプフロー試験方法）」に準じて、スランプフロー値を求めた。
（２）50cm到達時間
上記スランプフロー試験において、スランプフローが50cmに達するまでの時間を測定した。
（３）Ｖロート通過時間
土木学会規準コンクリート標準示方書「JSCE-F 512」に準じて、Ｖロート通過時間を測定した。
（４）圧縮強度
各配合物を、φ10×20cmの型枠を用いて成形した。成形後、２日間型枠内で養生し、脱型した。その後、材齢28、91日まで水中養生し、「JIS A 1108（コンクリートの圧縮強度試験方法）」に準じて圧縮強度を測定した。
結果を表３に示す。
【００４０】
【表３】

【００４１】
表３から、本発明の高流動コンクリート（実施例１〜１８）では、水／結合材比が１３〜２０質量％と小さい場合であっても、スランプフロー値が６７〜７５ｃｍ、スランプフローの５０ｃｍ到達時間が７〜２７秒、Ｖロート通過時間が２７〜６９秒であり、作業性や施工性に優れることがわかる。また、本発明の高流動コンクリートでは、材齢２８日で１００Ｎ／ｍｍ^２以上、材齢９１日で１４０Ｎ／ｍｍ^２以上の高強度を発現することがわかる。
一方、セメントと微粒子（シリカフューム）のみを含む結合材を用いた比較例１、２のコンクリートでは、スランプフロー値、スランプフローの５０ｃｍ到達時間、及びＶロート通過時間が、高流動コンクリート（実施例１〜１８）における値と比べて劣り、作業性や施工性が劣るものであった。
また、セメントと無機粒子のみを含む結合材を用いた比較例３、４のコンクリートでは、スランプフロー値、スランプフローの５０ｃｍ到達時間、及びＶロート通過時間が、高流動コンクリート（実施例１〜１８）における値と比べて劣り、作業性や施工性が劣るものであった。
【００４２】
【発明の効果】
本発明の高流動コンクリートは、硬化前には、自己充填性（高い流動性）及び良好な材料分離抵抗性を有し、施工性に極めて優れるとともに、硬化後には、120MPaを超える圧縮強度を有する等、機械的特性に優れる。[0001]
BACKGROUND OF THE INVENTION
The present invention has a self-filling property (high fluidity) and good material separation resistance before curing, is extremely excellent in workability, and is highly fluidized in mechanical properties such as compressive strength after curing. Concerning concrete.
[0002]
[Prior art]
Conventionally, concrete having excellent mechanical properties such as compressive strength has been developed.
For example, inorganic solid particles A (for example, silica dust particles) having a particle size of 50 to 0.5 μm and solid particles B (for example, at least 20% by mass of Portland cement having a particle size of 0.5 to 100 μm and at least one order larger than the particle A) A surface active dispersant (for example, a concrete superplasticizer such as a highly condensed naphthalene sulfonic acid / formaldehyde condensate) and an additional material C (selected from the group consisting of stone, metal fibers, etc.) A hydraulic composite material (concrete) is known (see, for example, Patent Document 1).
The hydraulic composite material described in this document has a compressive strength of 100 MPa or more after curing and is excellent in mechanical properties.
[0003]
[Patent Document 1]
Japanese Patent Publication No. 60-59182 (claim, page 32, column 63, table 1)
[0004]
[Problems to be solved by the invention]
In general, concrete having excellent mechanical properties (such as compressive strength) has the following advantages.
(1) When building buildings on site, the thickness of the concrete layer can be reduced, reducing the amount of concrete placement, reducing labor, reducing costs, and increasing use space. Etc. can be achieved.
(2) When manufacturing a precast member, the thickness of the precast member can be reduced, so that the weight can be reduced, and transportation and construction are facilitated.
(3) Abrasion resistance and durability against neutralization and creep are improved.
In view of these advantages {circle around (1)} to {circle around (3)}, there is a demand for concrete that is superior in mechanical properties to the hydraulic composite material (concrete) disclosed in Patent Document 1 described above.
[0005]
In addition, when building buildings etc. on site and manufacturing precast members, shortening the time for placing concrete and shortening the time required for vibration applied to concrete after placing, etc. From the viewpoint, it is advantageous to use high fluidity concrete having excellent fluidity and material separation resistance.
[0006]
However, the hydraulic composite material (concrete) disclosed in Patent Document 1 described above achieves both improvement in fluidity and material separation resistance before curing and improvement in mechanical properties (such as compressive strength) after curing. That was difficult. For example, in order to develop a compressive strength exceeding 120 MPa, it is necessary to reduce the water / binder ratio, so that the fluidity is reduced and the self-filling property cannot be obtained. On the other hand, if it is intended to ensure self-fillability, the water / binder ratio and the amount of water reducing agent increase, and it is difficult to develop a compressive strength exceeding 120 MPa.
Therefore, the present invention has a self-filling property (high fluidity) and good material separation resistance before curing, excellent workability, and has a compressive strength exceeding 120 MPa after curing. It aims at providing the high fluidity concrete which is excellent in a characteristic.
[0007]
[Means for Solving the Problems]
As a result of earnest research to achieve the above object, the present inventor obtained knowledge that the above object can be achieved by mixing a material having a specific particle size at a specific mixing ratio. Reached.
That is, the high fluidity concrete of the present invention (Claim 1) includes a cement 100 parts by weight of (A) Blaine specific surface area 2,500~5,000cm ² / g, (B) particles having a BET specific surface area of 5~25m ² / g 10 and 40 parts by weight, (C) inorganic particles A10~50 parts by weight of the Blaine specific surface area 5,000~30,000cm ² / g and, (H) inorganic particles B5~35 parts by weight of the Blaine specific surface area 2,000~5,000cm ² / g And (D) fine aggregate, (E) coarse aggregate, (F) water reducing agent, and (G) water, and the inorganic particles A are more than the cement and the inorganic particles B. It has a large specific surface area of brain, the difference between the specific surface area of the cement and the inorganic particles B is 100 cm ² / g or more, and the total amount of the inorganic particles A and the inorganic particles B is More than 10 parts by mass and less than 55 parts by mass with respect to 100 parts by mass, and the amount of water is a total amount of the cement, fine particles, inorganic particles A, and inorganic particles B. Characterized in that 10 to 30 parts by weight with respect to part.
The high-fluidity concrete configured in this way has self-fillability (high fluidity) and good material separation resistance before curing, and has excellent workability, and after curing, has a compressive strength exceeding 120 MPa. Excellent mechanical properties such as
[0009]
The high-fluidity concrete can include one or more kinds of fibers selected from the group consisting of metal fibers, organic fibers, and carbon fibers (Claim 2 ).
By including fibers such as metal fibers in this way, bending strength and the like can be improved.
The above high-fluidity concrete has a slump flow value measured according to “JIS A 1150 (concrete slump flow test method)” of 45 to 80 cm, and has a compressive strength after being cured under water until the age of 91 days. It can have a physical property of 120 N / mm ² or more (claim 3 ).
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, various Portland cements such as ordinary Portland cement, early-strength Portland cement, moderately hot Portland cement, low heat Portland cement and the like can be used as the cement used in the present invention to explain the present invention in detail.
In the present invention, when improving the early strength of concrete, it is preferable to use early-strength Portland cement. When improving the fluidity of concrete, medium-heated Portland cement or low-heat Portland cement is preferred. It is preferable to use an agent.
[0011]
The brane specific surface area of the cement is 2,500 to 5,000 cm ² / g, preferably 3,000 to 4,500 cm ² / g. If that value is less than 2,500 cm ² / g, the hydration reaction becomes inactive, there are drawbacks such as hard compressive strength is obtained in excess of 120 MPa, when it exceeds 5,000 cm ² / g, grinding of cement In addition, it takes time, and since the amount of water for obtaining a predetermined fluidity increases, there is a disadvantage that the amount of shrinkage after curing increases.
[0012]
Examples of the fine particles used in the present invention 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 fine particles of the present invention.
[0013]
The BET specific surface area of the fine particles is 5 to 25 m ² / g. When the value is less than 5 m ² / g, since the compactness of the particles constituting the concrete lacks a compactness, there is a drawback that it is difficult to obtain a compressive strength exceeding 120 MPa, and when it exceeds 25 m ² / g, Since the amount of water for obtaining a predetermined fluidity increases, there is a drawback that it is difficult to obtain a compressive strength exceeding 120 MPa.
[0014]
The compounding amount of the fine particles is 10 to 40 parts by mass, preferably 20 to 40 parts by mass with respect to 100 parts by mass of cement. When the blending amount is less than 10 parts by mass, it becomes difficult to develop a compressive strength exceeding 120 MPa, the mechanical properties are lowered, and the fluidity is extremely lowered. On the other hand, when the amount exceeds 40 parts by mass, the fluidity is lowered.
[0015]
Inorganic particles A and inorganic particles B blended as necessary are inorganic particles other than cement. 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.
In addition, the same kind of powder may be used for the inorganic particles A and the inorganic particles B, and different kinds of powders may be used.
[0016]
The inorganic particles A have a Blaine specific surface area of 5,000 to 30,000 cm ² / g, preferably 6,000 to 20,000 cm ² / g. Two or more inorganic particles may be used as the inorganic particles A as long as they are within the numerical range of the Blaine specific surface area.
Moreover, the inorganic particle A has a larger Blaine specific surface area than the cement and the inorganic particle B blended as necessary.
If the Blaine specific surface area of the inorganic particles A is less than 5,000 cm ² / g, the difference between the Blaine specific surface area of the cement is small, has drawbacks such that it becomes difficult to ensure the self-filling, 30,000 ² When it exceeds / g, it takes time and effort to grind, so that there are disadvantages such as difficulty in obtaining the material and difficulty in obtaining a predetermined fluidity.
Further, the inorganic particles A have a larger Blaine specific surface area than the cement and the inorganic particles B blended as necessary, so that the inorganic particles A are mixed with the cement and the inorganic particles B as needed. Therefore, self-filling properties and the like can be ensured.
[0017]
Difference Blaine specific surface area of the inorganic particles A and the cement, from the viewpoint of the strength developing property after curing and workability before curing (workability), preferably at least 1,000 cm ² / g, more at least 2,000 cm ² / g preferable.
In addition, when the inorganic particles B are blended, the difference in the Blaine specific surface area between the inorganic particles A and the inorganic particles B is 1,000 cm ² / g from the viewpoints of workability before curing (workability) and strength development after curing. The above is preferable, and 2,000 cm ² / g or more is more preferable.
[0018]
The compounding quantity of the inorganic particle A is 10-50 mass parts with respect to 100 mass parts of cement, Preferably it is 15-40 mass parts. When the blending amount is less than 10 parts by mass, the fluidity is lowered. On the other hand, when the blending amount exceeds 50 parts by mass, it is difficult to ensure self-filling properties when trying to develop a compressive strength exceeding 120 MPa after curing, and the workability is extremely lowered.
[0019]
The Blaine specific surface area of the inorganic particles B is 2,000 to 5,000 cm ² / g. The difference between the Blaine specific surface area of the cement and the inorganic particles B are workability (workability) before curing from the viewpoint of the strength developing property after curing, preferably 100 cm ² / g or more, more preferably 200 cm ² / g or more.
If the Blaine specific surface area of the inorganic particles B is less than 2,000 cm ² / g, it may be difficult to ensure self-filling properties.
[0020]
The compounding amount of the inorganic particles B is 35 parts by mass or less, preferably 5 to 35 parts by mass, and more preferably 10 to 30 parts by mass with respect to 100 parts by mass of cement. If the blending amount exceeds 35 parts by mass, the fluidity may be lowered and the workability may be lowered when trying to develop a compressive strength exceeding 120 MPa after curing.
When mix | blending the inorganic particle B, the total amount of the inorganic particle A and the inorganic particle B exceeds 10 mass parts with respect to 100 mass parts of cement, and is 55 mass parts or less, Preferably it is 25-55 mass parts. When the total amount exceeds 55 parts by mass, it is difficult to ensure self-filling properties when compressive strength exceeding 120 MPa is to be achieved after curing, and workability may be extremely reduced.
[0021]
As the fine aggregate, a fine aggregate used for ordinary concrete can be used. Specifically, for example, river sand, land sand, sea sand, crushed sand, silica sand, etc., or a mixture thereof can be mentioned.
The blending amount of the fine aggregate is preferably based on 100 parts by mass of the total amount of cement, fine particles, inorganic particles A, and inorganic particles B blended as necessary from the viewpoint of workability of the high fluidity concrete. 30 to 100 parts by mass.
The fine aggregate is preferably one having a content of particles of 75 μm or less of 2.0% by mass or less. By using the fine aggregate, the workability and the like of high-fluidity concrete in which the amount of the binder is large in the binder not containing the inorganic particles B is improved.
[0022]
As the coarse aggregate, coarse aggregate used for ordinary concrete can be used. Specifically, for example, gravel, crushed stone, or a mixture thereof can be used.
The amount of the coarse aggregate is preferably 100 parts by mass with respect to the total amount of cement, fine particles, inorganic particles A, and inorganic particles B blended as necessary, from the viewpoint of workability of the high fluidity concrete. 50 to 150 parts by mass.
[0023]
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.
[0024]
The blending amount of the water reducing agent is preferably 0.1 to 4.0 parts by weight in terms of solid content with respect to 100 parts by weight of the total amount of cement, fine particles, inorganic particles A, and inorganic particles B blended as necessary, and 0.2 to 1.0 parts by weight. Part by mass is more preferable. If the blending amount is less than 0.1 parts by mass, kneading becomes difficult and fluidity is lowered, so that self-filling properties cannot be obtained. When the blending amount exceeds 4.0 parts by mass, material separation and significant setting delay occur, and mechanical properties after curing may be deteriorated.
The water reducing agent can be used in a liquid or powder form.
[0025]
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 the total amount of cement, fine particles, inorganic particles A and inorganic particles B blended as necessary. is there. When the amount of water is less than 10 parts by mass, kneading becomes difficult, fluidity is lowered, and self-fillability cannot be obtained. If the amount of water exceeds 30 parts by mass, the mechanical properties (such as compressive strength) after curing will decrease.
[0026]
In the present invention, it is preferable to include one or more kinds of fibers selected from metal fibers, organic fibers and carbon fibers in the high fluidity concrete from the viewpoint of greatly increasing the bending strength after curing.
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 high-fluidity concrete and improving the bending strength after curing. More preferably, the diameter is 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.
[0027]
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.
[0028]
Preferable examples of metal fibers include, for example, interfacial adhesion strength (unit of adhesion surface) to high-fluidity concrete made of steel fibers having a diameter of 0.5 mm or less and a tensile strength of 1 to 3.5 GPa and a compressive strength of 120 MPa. The maximum tensile force per area) 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.
[0029]
The blending amount of the metal fiber is preferably 4% or less, more preferably 0.5 to 3%, and particularly preferably 1 to 3% in terms of volume percentage in the high fluidity concrete. If the blending amount exceeds 4%, the unit water amount increases in order to ensure workability at the time of kneading, and even if the blending amount is increased, the reinforcing effect of the metal fiber is not improved. Since it becomes easy to produce what is called a fiber ball in a kneaded material, it is not preferable.
[0030]
Examples of the organic fiber include vinylon fiber, polypropylene fiber, polyethylene fiber, and aramid fiber.
The size of the organic fiber is preferably 0.005 to 1.0 mm in diameter and 2 to 30 mm in length from the viewpoint of preventing material separation of the organic fiber in the high-fluidity concrete 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. The aspect ratio (fiber length / fiber diameter) of the organic fiber is preferably 20 to 200, more preferably 30 to 150.
The blending amount of the organic fiber is preferably 10% or less, more preferably 1 to 9%, and particularly preferably 2 to 8% as a volume percentage in the high fluidity concrete. If the blending amount exceeds 10%, the unit water amount increases in order to ensure workability at the time of kneading, and even if the blending amount is increased, the reinforcing effect of the organic fiber is not improved. Since it becomes easy to produce what is called a fiber ball in a kneaded material, it is not preferable.
Examples of the carbon fiber include PAN-based carbon fiber and pitch-based carbon fiber.
The dimensions and blending amount of the carbon fiber are the same as those of the organic fiber described above.
[0031]
In the present invention, the slump flow value of the high-fluidity concrete is preferably 45 to 80 cm, more preferably 50 to 78 cm, from the viewpoint of workability and prevention of material separation.
In the present specification, the slump flow value means a value measured according to the test method of “JIS A 1150 (concrete slump flow)”.
In the above slump flow test, the time until the slump flow reaches 50 cm is preferably 35 seconds or less, more preferably 30 seconds or less, from the viewpoint of workability and the like.
[0032]
In the present invention, the V funnel passage time of the high fluidity concrete is preferably 85 seconds or less, more preferably 75 seconds or less from the viewpoint of workability and the like.
In addition, in this specification, V funnel passage time means the value measured according to the test method of Japan Society of Civil Engineers standard concrete standard specification "JSCE-F 512".
In the present invention, the compressive strength after the high fluid concrete is cured under water until the age of 91 days is preferably 120 N / mm ² or more, more preferably 130 N / mm ² or more, still more preferably 140 N / mm ² or more, particularly preferably. Is 150 N / mm ² or more.
In the present invention, the compressive strength after cured in water of high flow concrete until age of 28 days, preferably 100 N / mm ² or more, more preferably 105N / mm ² or more, and particularly preferably 110N / mm ² or more.
In the present specification, the compressive strength means a value measured according to the test method of “JIS A 1108 (Concrete compressive strength test method)”.
[0033]
The kneading method of the high fluidity concrete of the present invention is not particularly limited. For example, (a) materials other than water, water reducing agent and coarse aggregate (specifically, cement, fine particles, inorganic particles A, inorganic Particle B and fine aggregate) are mixed in advance to prepare a premix material, and the premix material, water, water reducing agent and coarse aggregate are put into a mixer and kneaded, (b) powdery Prepare a premixed material by mixing materials other than water and coarse aggregate (specifically, cement, fine particles, inorganic particles A, inorganic particles B, water reducing agent and fine aggregate) in advance. The premix material, water, and coarse aggregate can be prepared and mixed in a mixer and kneaded. (C) Each material can be individually added to the mixer and kneaded. .
[0034]
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. Further, the curing method is not particularly limited, and air curing, steam curing, or the like may be performed.
[0035]
【Example】
Hereinafter, the present invention will be described by way of examples.
[1. Materials used]
The following materials were used.

[0036]
[2. Mixing and kneading of concrete]
Using the binders and other materials shown in Table 1, concretes shown in Table 2 were prepared. The kneading was performed for 180 seconds using a biaxial forced kneading mixer (0.1 m ³ ).
[0037]
[Table 1]

[0038]
[Table 2]

[0039]
[3. Evaluation]
The physical properties of the prepared concrete were evaluated as follows.
(1) Slump flow The slump flow value was determined according to “JIS A 1150 (concrete slump flow test method)”.
(2) Time to reach 50 cm In the above-described slump flow test, the time until the slump flow reached 50 cm was measured.
(3) V funnel passage time The V funnel passage time was measured according to the Japan Society of Civil Engineers Standard Concrete Standard Specification “JSCE-F 512”.
(4) Compressive strength Each compound was molded using a mold of φ10 × 20 cm. After molding, it was cured in a mold for 2 days and demolded. Thereafter, it was cured in water until the age of 28 and 91 days, and the compressive strength was measured according to “JIS A 1108 (Method for testing compressive strength of concrete)”.
The results are shown in Table 3.
[0040]
[Table 3]

[0041]
From Table 3, in the high fluidity concrete of the present invention (Examples 1 to 18 ), even when the water / binder ratio is as small as 13 to 20% by mass, the slump flow value is 67 to 75 cm and the slump flow is 50 cm. The arrival time is 7 to 27 seconds and the V funnel passage time is 27 to 69 seconds, which indicates that the workability and workability are excellent. Moreover, in the high fluidity concrete of this invention, it turns out that the high intensity | strength of 100 N / mm < ² > or more is expressed at the age of 28 days and 140 N / mm < ² > or more at the age of 91 days.
On the other hand, in the concrete of Comparative Examples 1 and 2 using a binder containing only cement and fine particles (silica fume), the slump flow value, the 50 cm arrival time of the slump flow, and the V funnel passage time are high fluid concrete (Example 1). It was inferior compared with the value in ~ 18 ), and workability and workability were inferior.
Further, the concrete of Comparative Examples 3 and 4 using a binder containing only cement and inorganic particles, the slump flow value, 50 cm arrival time of slump flow and V funnel transit time, high fluidity concrete (Example 1-18 ) And inferior workability and workability.
[0042]
【The invention's effect】
The high-fluidity concrete of the present invention has a self-filling property (high fluidity) and good material separation resistance before curing, has excellent workability, and has a compressive strength exceeding 120 MPa after curing. Excellent mechanical properties.

Claims (3)

(A) and cement 100 parts by weight of the Blaine specific surface area 2,500~5,000cm ² / g, and the fine particles 10 to 40 parts by weight of (B) BET specific surface area of 5~25m ² / g, (C) Blaine specific surface area 5,000 to 30,000 and cm ² / g of the inorganic particles A10~50 parts by weight inorganic particles B5~35 parts by weight (H) Blaine specific surface area 2,000~5,000cm ² / g, and (D) fine aggregate, (E) coarse aggregate Material, (F) a water reducing agent, and (G) water, and the inorganic particles A have a larger Blaine surface area than the cement and the inorganic particles B , and the cement and the inorganic The difference in Blaine specific surface area of the particles B is 100 cm ² / g or more, and the total amount of the inorganic particles A and the inorganic particles B exceeds 10 parts by mass with respect to 100 parts by mass of the cement, 55 parts by mass or less, the amount of the water, the cement, fine, high flow co, characterized in that the total amount 100 parts by weight of inorganic particles a and the inorganic particles B is 10 to 30 parts by weight Cleat. High fluidity concrete according to claim 1 comprising a metal fiber, one or more fibers selected from the group consisting of organic fibers and carbon fibers. The slump flow value measured according to “JIS A 1150 (concrete slump flow test method)” is 45 to 80 cm, and the compressive strength after underwater curing until the age of 91 days is 120 N / mm ² or more. The high fluidity concrete according to claim 1 or 2 .