JP2002068806A - Ultrahigh strength hydraulic composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrahigh strength hydraulic composition capable of producing a hardened body having an ultrahigh strength (compressive strength) of >=150 MPa even when the amount of an expensive ultrafine powder (e.g. silica fume) used is reduced. SOLUTION: In the ultrahigh strength hydraulic composition containing at least cement, a pozzolan-like fine powder, a fine aggregate of <=2 mm grain diameter, a water reducing agent and water, part or all of the pozzolan-like fine powder is diatomaceous earth. Preferably, metallic fibers and/or organic fibers, an inorganic powder of 3-20 μm average particle diameter and fibrous grains or flaky grains of <=1 mm average grain size are further contained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ultrahigh-strength hydraulic composition capable of exhibiting ultrahigh strength (compressive strength) of 150 MPa or more.

[0002]

2. Description of the Related Art In a hydraulic composition mainly composed of cement, in order to produce an ultra-high-strength cured product having a compressive strength of 150 MPa or more, an average particle size of silica fume or the like is 1.0 μm.
The following ultrafine powder is blended.

[Problems to be solved by the invention]

[0003] Ultrafine powders such as the silica fumes described above are generally expensive. In order to produce a cured product having an ultra-high strength of 150 MPa or more, it is necessary to use a large amount of the ultrafine powder, and the price of the hydraulic composition becomes considerably high.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, if a specific material is used, the amount of expensive ultrafine powder (such as silica fume) can be reduced. Also, the present inventors have found that a cured product having an ultra-high strength (compression strength) of 150 MPa or more can be produced, and have reached the present invention.

That is, the present invention provides at least cement,
Pozzolanic fine powder, fine aggregate having a particle size of 2 mm or less, ultra-high strength hydraulic composition containing water reducing agent and water, characterized in that part or all of the pozzolanic fine powder is diatomaceous earth It is an ultra-high strength hydraulic composition (Claim 1). further,
In the present invention, metal fibers and / or organic fibers (Claim 2), inorganic powder having an average particle size of 3 to 20 μm (Claim 5), fibrous particles or flaky particles having an average particle size of 1 mm or less (Claim 6) It is preferable to include

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Ultra-high strength hydraulic composition of the present invention, at least,
Cement, pozzolanic fine powder, fine aggregate with a particle size of 2 mm or less,
It contains a water reducing agent and water, and part or all of the pozzolanic fine powder is diatomaceous earth. In the present invention, the type of cement is not limited, and ordinary Portland cement, early-strength Portland cement, moderately heated Portland cement, various portland cements such as low-heat Portland cement, blast furnace cement, and mixed cements such as fly ash cement are used. be able to. In the present invention, when it is intended to improve the early strength after curing, it is preferable to use an early-strength Portland cement, and when it is intended to improve the fluidity when kneaded with water, a moderately heated Portland cement or It is preferred to use low heat Portland cement.

In the present invention, diatomaceous earth is used as the pozzolanic fine powder. Diatomaceous earth preferably has a particle size of 1 to 100 μm, more preferably 5 to 50 μm, and still more preferably 10 to 30 μm from the viewpoint of strength development and durability after curing. In the present invention, other pozzolanic fine powder (silica fume, silica dust, fly ash, slag, etc.) may be used as the pozzolanic fine powder together with the diatomaceous earth, In consideration of the price of the hard composition, etc., the amount of the other pozzolanic fine powder is preferably 100 parts by weight or less based on 100 parts by weight of diatomaceous earth. The blending amount of the pozzolanic fine powder is preferably 5 to 50 parts by weight based on 100 parts by weight of cement. When the amount of the pozzolanic fine powder is small, the strength after curing is undesirably reduced. If the amount of the pozzolanic fine powder is increased, the unit water amount is increased, so that the strength and durability after curing are undesirably reduced.

In the present invention, fine aggregate having a particle size of 2 mm or less is used. Here, the particle size of the fine aggregate in the present invention is an 85% weight cumulative particle size. If the particle size of the fine aggregate exceeds 2 mm, the strength after curing is undesirably reduced. In the present invention, it is preferable to use fine aggregate having a maximum particle size of 2 mm or less, and it is more preferable to use fine aggregate having a maximum particle size of 1.5 mm or less. As fine aggregate, river sand,
Land sand, sea sand, crushed sand, quartz sand or a mixture thereof can be used. The amount of the fine aggregate is 50 to 250 parts per 100 parts by weight of the cement, from the viewpoint of fluidity, strength after curing, and durability.
Part by weight is preferred, and 80 to 180 parts by weight is more preferred.

As the water reducing agent, a lignin-based, naphthalene-sulfonic acid-based, melamine-based, 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. The compounding amount of the water reducing agent is preferably 0.5 to 4.0 parts by weight in terms of solid content based on 100 parts by weight of cement. If the amount of the water reducing agent (in terms of solid content) is less than 0.5 part by weight with respect to 100 parts by weight of cement, kneading becomes difficult, and the fluidity is low and work such as molding becomes difficult. Water reducing agent amount (solid content conversion) is 4.0 per 100 parts by weight of cement
Exceeding the weight parts is not preferred because the strength and durability after curing are reduced. The water reducing agent can be used in either liquid or powder form.

The amount of water is 10 to 3 parts per 100 parts by weight of cement.
The amount is preferably 0 parts by weight, more preferably 15 to 25 parts by weight. If the amount of water is less than 10 parts by weight with respect to 100 parts by weight of cement, kneading becomes difficult, and the flowability is low, and the work such as molding becomes difficult. Cement 100
If the amount of water exceeds 30 parts by weight with respect to part by weight, the strength and durability after curing are undesirably reduced.

In the present invention, from the viewpoint of greatly increasing the flexural strength after curing, it is preferable that the ultrahigh-strength hydraulic composition contains metal fibers and / or organic fibers. Examples of the metal fiber include a steel fiber and an amorphous fiber. Among them, the steel fiber is excellent in strength, and is preferable from the viewpoint of cost and availability. The metal fiber preferably has a diameter of 0.01 to 1.0 mm and a length of 2 to 30 mm. When the diameter is less than 0.01 mm, the strength of the fiber itself is insufficient, and the fiber tends to be cut when subjected to tension. If the diameter is more than 1.0 mm, the number of pieces with the same compounding amount decreases, and the effect of improving the bending strength decreases. If the length exceeds 30 mm, fiber balls tend to be formed during kneading. If the length is less than 2 mm, the effect of improving the bending strength decreases. The amount of metal fiber
It is preferably less than 4%, more preferably less than 3% of the volume of the ultra high strength hydraulic composition. When the blending amount of the metal fiber increases, the unit water amount also increases in order to ensure workability during kneading, etc., so the blending amount of the metal fiber is preferably the above-mentioned amount.

Examples of the organic fiber include vinylon fiber, polypropylene fiber, polyethylene fiber, aramid fiber, carbon fiber and the like. Organic fibers are 0.005-1.0m in diameter
m and a length of 2 to 30 mm are preferred. The blending amount of the organic fiber is preferably less than 10%, more preferably less than 8% of the volume of the ultrahigh strength hydraulic composition. In the present invention, it is possible to use metal fibers and organic fibers in combination.

In the present invention, from the viewpoint of increasing the packing density after curing and improving the durability, the ultrahigh-strength hydraulic composition has an average particle size of 3 to 20 μm, more preferably 4 to 10 μm.
It is preferable to include a μm inorganic powder. Examples of the inorganic powder include quartz powder, limestone powder, carbide, and nitride. Among them, quartz powder is preferable from the viewpoint of cost and the stability of the quality of the cured product. Examples of the quartz powder include quartz and amorphous quartz, and opal and cristobalite silica-containing powders. The amount of the inorganic powder should be adjusted according to the fluidity, strength and durability after hardening.
It is preferably 50 parts by weight or less, more preferably 20 to 35 parts by weight, per 100 parts by weight.

In the present invention, from the viewpoint of increasing the toughness after curing, it is preferable that the ultrahigh-strength hydraulic composition contains fibrous particles or flaky particles having an average particle size of 1 mm or less. Here, the particle size of a particle is the size of its maximum dimension (in particular, its length for fibrous particles). Examples of the fibrous particles include wollastonite, bauxite, and mullite, and examples of the flaky particles include mica flake, talc flake, vermiculite flake, and alumina flake. The mixing amount of the fibrous particles or flaky particles is determined based on the flowability, strength and durability after curing, and the amount of cement 100
It is preferably 35 parts by weight or less, more preferably 10 to 25 parts by weight based on parts by weight. From the viewpoint of enhancing the toughness after curing, it is preferable to use fibrous particles having a needleiness expressed by a length / diameter ratio of 3 or more.

The method of kneading the ultrahigh-strength hydraulic composition of the present invention includes, for example, 1) mixing materials other than water and a water reducing agent in advance (premix), and mixing the premix, water, and the water reducing agent. Pour into mixer and knead. 2) Materials other than water are mixed in advance (a premix, but a water reducing agent of a powder type is used), and the premix and water are charged into a mixer and kneaded. 3) Each material is individually charged into a mixer and kneaded. And the like.

The mixer used for kneading may be of any type used for kneading ordinary concrete. For example, an oscillating mixer, a pan-type mixer, a biaxial kneading mixer and the like are used.

After kneading, the kneaded material is put into a predetermined mold, molded, then cured and cured. In addition, in this invention, what is necessary is just to perform air curing, steam curing, etc. for curing.

The ultrahigh-strength hydraulic composition of the present invention has a
A cured product exhibiting a compressive strength exceeding Pa and a bending strength exceeding 20 MPa can be obtained. The cured product of the ultrahigh strength hydraulic composition of the present invention is dense and has excellent durability.

[0019]

The present invention will be described below with reference to examples. 1. Materials used The following materials were used. 1) Cement; Low heat Portland cement (manufactured by Taiheiyo Cement Corporation) 2) Pozzolanic fine powder; diatomaceous earth (particle size: 10 to 30 μm) Weight ratio) Mixed product 4) Metal fiber; Steel fiber (diameter: 0.2 mm, length: 15 mm) 5) High-performance AE water reducing agent; Polycarboxylic acid-based high-performance AE water reducing agent 6) Water; tap water 7) Inorganic powder ; Quartz powder (average particle size 7μm) 8) Fibrous particles; Wollastonite (average length 0.3mm, length / diameter ratio 4)

Example 1 Biaxial kneading of 100 parts by weight of low heat Portland cement, 32.5 parts by weight of diatomaceous earth, 120 parts by weight of fine aggregate, 1.0 part by weight of a high-performance AE water reducing agent (solid content based on cement), and 22 parts by weight of water It was charged into a mixer and kneaded. The composition was molded in a mold of φ50 × 100 mm, placed at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours. The compressive strength (average value of three) of the cured product is 180M
Pa. The composition was molded in a mold frame of 4 × 4 × 16 cm, placed 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 product was 20 MPa.

Example 2 100 parts by weight of low heat Portland cement, 32.5 parts by weight of diatomaceous earth, 120 parts by weight of fine aggregate, 1.0 part by weight of high-performance AE water reducing agent (solid content based on cement), 22 parts by weight of water, 30 parts of quartz powder Parts by weight, 24 parts by weight of wollastonite, and steel fiber (2% of the volume in the hydraulic composition) were charged into a biaxial kneading mixer and kneaded. Compressive strength and flexural strength were measured as in Example 1.
As a result, the compressive strength was 200 MPa and the bending strength was 40 MPa.

[0022]

As described above, the ultra-high-strength hydraulic composition of the present invention has an ultra-high strength (compression strength) of 150 MPa or more even when the amount of expensive ultrafine powder (silica fume, etc.) is reduced. ) Can be produced.

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Claims (6)

[Claims] 1. An ultra-high-strength hydraulic composition comprising at least cement, pozzolanic fine powder, fine aggregate having a particle size of 2 mm or less, a water reducing agent and water, wherein part or all of the pozzolanic fine powder is silicon. An ultra-high-strength hydraulic composition characterized by being algae soil. 2. The ultra-high-strength hydraulic composition according to claim 1, comprising metal fibers and / or organic fibers. 3. The metal fiber has a diameter of 0.01 to 1.0 mm and a length of 2 to 30.
The ultrahigh-strength hydraulic composition according to claim 2, which is a steel fiber of mm. 4. An organic fiber having a diameter of 0.005 to 1.0 mm and a length of 2
The ultrahigh-strength hydraulic composition according to claim 2, which is at least one fiber selected from vinylon fiber, polypropylene fiber, polyethylene fiber, aramid fiber, and carbon fiber of up to 30 mm. 5. The ultrahigh-strength hydraulic composition according to claim 1, further comprising an inorganic powder having an average particle size of 3 to 20 μm. 6. The ultrahigh-strength hydraulic composition according to claim 1, comprising fibrous particles or flaky particles having an average particle size of 1 mm or less.