JPH06211550A - Hydraulic material - Google Patents

Abstract

PURPOSE:To prepare a hydraulic material having sufficient flowability and small in water to binder ratio by using a usual cement and accordingly capable of obtaining a hardened body extremely improved in workability and application property and excellent in strength and durability. CONSTITUTION:This hydraulic material contains at least cement and silica fume as the binder, a water soluble vinyl copolymer of <1wt.% based on the binder as a dispersing material and 60wt.% water based on the binder. This hydraulic material contains a granule made by flocculating the silica fume <=0.5mum in the particle diameter of the primary particle on the all or partial surface of the cement particle as a main material and a binder wherein the volume ratio of content of the particles having <=1mum particle diameters in these having 0.1-35mum particle diameters is <=10%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to hydraulic materials. Hydraulic materials such as concrete, mortar and grout are prepared by mixing a binder such as Portland cement, fly ash cement and blast furnace slag cement, water, aggregate and a trace amount of a dispersant. The strength and durability of a cured product obtained by curing such a hydraulic material are generally governed by the ratio of water to the binder, and the smaller the ratio, the better. However, the smaller the ratio of water to the binder, the lower the fluidity of the hydraulic material. As a result, even if the ratio of water to the binder is reduced to improve the performance of the hydraulic material, the performance cannot be improved beyond the limit of moldability. There is a contradictory relationship between the performance improvement and the fluidity improvement of hydraulic materials. The present invention solves the problems of such a hydraulic material, and is applicable to the preparation of high-strength mortar and high-strength concrete, and relates to a highly fluid hydraulic material with significantly improved workability and workability. is there.

[0002]

2. Description of the Related Art Conventionally, a large amount of a dispersant has been used as a hydraulic material, and fine particles of one order or more smaller than the particles are dispersed between cement particles in a uniform state without local agglomeration. It has been proposed that the fluidity of the material be improved, and as a result, the strength and durability of the hydraulic material be improved (Japanese Patent Publication No. 60-59182). However, in this conventional proposal, fine particles smaller than one order of magnitude are dispersed between cement particles in a uniform state without local aggregation, so that the viscosity of water between cement particles is apparently increased. There is a drawback that the action becomes strong and the action of improving the fluidity is limited.

Further, conventionally, as a hydraulic material, one using a capsule-type spheroidized cement in which silica fume is adhered and formed on the entire surface has been proposed (Japanese Patent Laid-Open No. 1924/1990).
39). However, this conventional proposal has a drawback that the spheroidized cement must be produced as a major premise because the fluidity of the hydraulic material is improved by the bearing action of the spheroidized cement itself.

[0004]

The problem to be solved by the present invention is that even if an attempt is made to prepare a hydraulic material capable of improving the strength and durability of a hardened body by using a conventional cement in the conventional proposal, it is sufficient. The point is that no fluidity can be obtained, and therefore only workability and workability that are extremely poor can be obtained.

[0005]

However, the present inventors have
As a result of diligent research to solve the above problems, a specific particle having a specific silica fume agglomerated on the surface of cement particles as a main material and a specific particle having a small particle size is a binder at a predetermined ratio or less, the bond. It has been found that a hydraulic material containing a specific dispersant in a predetermined proportion or less relative to the material and water in a predetermined proportion or less relative to the binder is properly suitable.

That is, the present invention is based on at least cement and silica fume as a binder, less than 1% by weight of a water-soluble vinyl copolymer as a dispersant with respect to the binder, and 60% by weight or less of water with respect to the binder. Which is a hydraulic material containing a main component is a particle in which silica fume having primary particles having a particle diameter of 0.5 μm or less is aggregated on the whole surface or a partial surface of cement particles and having a particle diameter of 0. 1-3
A hydraulic material comprising a binder having a volume ratio of particles having a particle diameter of 1 μm or less in particles having a diameter of 5 μm of 10% or less.

The binders used in the present invention are cement and silica fume. Examples of the cement include Portland cement, fly ash cement, blast furnace slag cement and the like, but Portland cement is 20% by weight.
The above content is preferable, and the one containing 30% by weight or more is more preferable. These cements usually have an average particle size of 5 to 50 μm, and contain about 5% by volume of particles having a particle size of 1 μm or less. As the silica fume, those having a primary particle diameter of 0.5 μm or less are used, but those containing 60% by weight or more of vitreous silica and having a specific surface area of 5 to 100 m ² / g are used. It is preferable to use one having a viscosity of 10 to 50 m ² / g. The content of silica fume in the binder is not particularly limited, but is preferably 5 to 35% by weight, and more preferably 10 to 30% by weight. This is because the hydraulic material to be prepared has higher fluidity, and the cured product exhibits higher strength and durability.

According to the present invention, 60% of the above binder is used.
Use up to wt% water. The proportion of water is preferably as low as possible to knead the hydraulic material, and in this sense, it is preferably used in the range of 20 to 40% by weight relative to the binder.

The gist of the present invention is a particle in which silica fume having a primary particle size of 0.5 μm or less is aggregated on the whole surface or a partial surface of cement particles (hereinafter referred to as a coated particle).
Particles having a particle diameter of 1 μm or less in the particles having a particle diameter of 0.1 to 35 μm as a main material and having the coated particles as a main material (hereinafter, referred to as fine particles). )
Is about 10% by volume or less.

Although it is difficult to specify the content of fine particles, it is usually the primary particles of silica fume.
Secondary particles of silica fume in which secondary particles are agglomerated, primary particles of cement having a particle diameter of 1 μm or less when slightly mixed in cement, secondary particles of cement in which primary particles are agglomerated, Includes composite particles in which such cement particles and silica fume particles are agglomerated with each other.

In the coated granule, the coverage of the surface of the cement particle with silica fume is preferably 50% or more on average with respect to the entire surface of the cement particle.
It is more preferably at least 5%. The coating ratio means the total average of the coated particles, and the numerical value can be roughly estimated from the laser microscope photograph and SEM photograph described later. It is necessary to use a specific dispersant in order to preferentially form the coated particles and reduce the fine particles to a predetermined ratio or less.

The dispersant used in the present invention is a water-soluble vinyl copolymer. Among them, a carboxylate group as a hydrophilic group,
Water-soluble vinyl copolymers having sulfonate groups and polyoxyalkylene graft chains are preferred. Examples of such water-soluble vinyl copolymers include those described in JP-A-1-226757 and JP-A-4-209613.
A salt of a highly condensed naphthalene sulfonic acid formalin or a salt of lignin sulfonic acid, which is generally used as a dispersant, cannot form the above-mentioned coated particles and the fine particles cannot be reduced to a predetermined ratio or less. In the present invention, the content ratio of the dispersant is less than 1% by weight with respect to the binder,
It is preferably 0.05% by weight or more and less than 1% by weight, and 0.2 to
0.8% by weight is more preferable. When the content of the dispersant is 1% by weight or more, particularly when it is a large amount exceeding 2% by weight, the content of the fine particles increases, and further, the aggregate is separated. Liquidity is not obtained.

When the dispersant is used in an amount of 1% by weight or more with respect to the binder, especially when used in a large amount exceeding 2% by weight, the ratio of fine particles increases, mainly because silica fume or cement is kneaded in water. In doing so, due to the action of the dispersant, mechanical factors, surface physical properties of the particles, etc., the primary particles of silica fume, the agglomerated particles of silica fume with a low degree of agglomeration, and the primary particles of finely mixed fine cement This is because, etc. are maintained in a stable dispersed state, and thus it is difficult to form a coated particle in which silica fume is aggregated on the surface of the cement particle. The fine particles having a particle size of 1 μm or less have an effect of increasing the viscosity of the water phase existing between them and decreasing the fluidity. Therefore, it is possible to obtain a desired fluidity by suppressing the ratio of such fine particles to a predetermined value or less. The proportion of such fine particles in the present invention is 10 in a particle having a particle size of 0.1 to 35 μm.
It is preferably not more than 8% by volume, but not more than 8% by volume.

In the present invention, the presence of relatively large silica fume agglomerated particles having a particle size of more than 1 μm causes further agglomeration, resulting in granules larger than the cement particles and not being stably dispersed. Unless there is a problem like this, there is no particular problem. This is because they reduce the shear deformation resistance of the prepared hydraulic material and improve the fluidity.

The hydraulic material of the present invention is prepared by kneading cement, silica fume, a dispersant and water. Although the present invention does not particularly limit the preparation method itself, a method is preferred in which an aqueous dispersion of silica fume is prepared in advance, and cement is added thereto and kneading. In this case, the dispersant may be dissolved in water in advance when preparing the aqueous dispersion of silica fume, or may be added later to the aqueous dispersion of silica fume.

In the present invention, the above-mentioned aqueous dispersion of silica fume has a particle diameter of 1 μm or less, preferably 0.5 to 1 μm, in the total particles of silica fume dispersed in water. The volume ratio is preferably 30% or more, more preferably 50% or more. The present invention is not particularly limited to a method for preparing an aqueous dispersion of silica fume having such a particle size distribution, but a mechanical dispersion method using ultrasonic waves in combination is preferable, and the water-soluble vinyl copolymer It is more preferable to use a dispersant comprising a combination.

The hydraulic material of the present invention contains cement and silica fume as a binder, a water-soluble vinyl copolymer as a dispersant, and water as described above, and further contains sand, stone, It includes mortar, concrete, reinforced concrete, and the like obtained by containing aggregates such as artificial lightweight aggregates, inorganic foams, and inorganic sintered bodies, and various reinforcing fibers.

[0018]

EXAMPLES Examples and the like will be given below to concrete the constitution and effects of the present invention. In the following Examples and the like, "parts" means "parts by weight" and "%" means "% by weight excluding the amount of air and the proportion of fine particles". Test Category 1 (Preparation and Evaluation of Concrete) -Preparation of Concrete Under the three types of mixing conditions shown in Table 1, cement, silica fume, fine aggregate and coarse aggregate were put into a pan-type forced mixer having a capacity of 50 liters, Further, the dispersant was added together with water and kneaded at 20 ° C. for 2 minutes to prepare concrete.
The proportion of silica fume in the binder and the type and amount of the dispersant added are shown in Tables 2 and 3.

-Evaluation-Measurement of slump, air content and compressive strength For each prepared concrete, slump, air content,
The compressive strength after 28 days is JIS-A110.
1, JIS-A1128, JIS-A1108 was measured. The slump was measured immediately after kneading. The results are shown in Tables 2 and 3. Further, in order to evaluate the viscosity of concrete, the L flow rate was measured immediately after mixing. What is the L flow rate?
297528 and the value measured by the L flow test method proposed in JP-A 1-297529, and the higher the L flow rate, the lower the viscosity of concrete and the better the fluidity.

..Measurement of proportion of fine particles Immediately after screening the concrete immediately after mixing with a 2.5 mm screen, the particle diameter is adjusted to a range of 0.1 to 35 .mu.m using a laser diffraction type particle size distribution measuring device. The particle size distribution of a certain particle was measured, and the volume ratio of the fine particle having a particle diameter of 1 μm or less was calculated. The results are shown in Tables 2 and 3.

[0021]

[Table 1]

In Table 1, binder: cement + silica fume Cement: ordinary Portland cement silica fume: average particle size 0.1 μm, specific gravity 2.3
5, specific surface area 14.1 m ² / g, vitreous silica content 93.8% Fine aggregate: specific gravity 2.61, sand absorption of 1.53% Coarse aggregate: specific gravity 2.70, water absorption 2.70% crushed limestone

[0023]

[Table 2]

[0024]

[Table 3]

In Tables 2 and 3, the amount of the dispersant added: the solid content ratio to the binder (%) A-1: sodium methacrylate / methoxy polyethylene glycol methacrylate / sodium methallyl sulfonate = 60/35/5 ( Molar ratio) Copolymer, average molecular weight 5000 (water-soluble vinyl copolymer described in JP-A-1-226757) R-1: Salt of highly condensed formalin naphthalene sulfonate R-2: Sodium lignin sulfonate Comparative Example 1 , 3: No slurry was formed, and kneading was impossible. Comparative Example 6: L flow rate and compressive strength were not measured because the aggregate was separated.

Test Category 2 (Preparation and Evaluation of Silica Fume-Cement Paste) Preparation of Silica Fume-Cement Paste Two types of silica fume-cement paste under the mixing conditions shown in Table 4 were subjected to the following methods A and B. Prepared. The types of dispersants used and the amounts added are shown in Table 5.

[0027]

[Table 4]

Method A: In all cases, the materials described in Test Category 1 were used. In a Hobart mixer, ordinary Portland cement, silica fume and a dispersant previously dissolved in kneading water were charged and kneaded for 5 minutes. Silica fume
A cement paste was prepared. Method B: All of the materials described in Test Category 1 were used, a dispersant previously mixed and dissolved in water and silica fume were put into an ultrasonic dispersion tank, and ultrasonic waves were applied at a frequency of 20 KHz to obtain silica. An aqueous dispersion of fume was prepared. The particle size distribution of the silica fume aqueous dispersion obtained here was measured. Then, an aqueous dispersion of ordinary Portland cement and silica fume was put into a Hobart mixer and kneaded for 5 minutes to prepare a silica fume-cement paste.

-Evaluation-Observation of granules Water was added to the prepared silica fume-cement paste to prepare a suspension. Dispersed particles were observed with a laser microscope photograph for this suspension. Also, add this suspension to filter paper (No.
5C), and after washing with water, the precipitate on the filter paper was observed with an SEM (freezing method) photograph. The results are shown in Table 5.

.. Measurement of proportion of fine particles Immediately after mixing the silica fume-cement paste with a laser diffraction type particle size distribution measuring apparatus, the particle size of the particles is in the range of 0.1 to 35 .mu.m. The distribution was measured and the volume ratio of fine particles having a particle diameter of 1 μm or less was calculated. The results are shown in Table 5.

[0031]

[Table 5]

In Table 5, * 1: In an aqueous dispersion of silica fume, the particle size is 1 μm in a particle having a particle size in the range of 0.1 to 35 μm.
Volume ratio (%) of the following particles * 2: In silica fume-cement paste, the volume ratio (%) of particles having a particle diameter of 1 µm or less among particles having a particle diameter of 0.1 to 35 µm. * 3: State of cement particles observed by laser microscope photograph * 4: State of cement particles observed by SEM photograph a ≧ b; consists of states a and b, where a and b are almost the same amount or a A little more a>b; consists of states a and b, and there are more a's a >>b; most of them are states a and a little b is included a; most of them are states a d >>c; C is included in d; most of the state is d. Comparative Example 7: Slurry was not formed and kneading was impossible.

1 and 2 are schematic diagrams showing the state of the cement particles of the example, and FIGS. 3 and 4 are schematic diagrams showing the state of the cement particles of the comparative example. 1 is silica fume 21 on all surfaces of cement particles 11 and 12,
22 shows an aggregated state a, and FIG. 2 shows cement particles 1
Silica fume 2 on the surface of 50% or more of 3,14
The state b in which 3, 24 are aggregated is further shown in FIG. 3 on the surface of the cement particles 15, 16 with silica fume 25, 2
6 shows an aggregated state c, and FIG. 4 shows cement particles 1
The states d in which silica fume is not aggregated on the surfaces of Nos. 7 and 18 are schematically shown.

[0034]

As is apparent from the above, according to the present invention described above, it is possible to prepare a hydraulic material having a sufficient fluidity and a small water binder ratio by using ordinary cement. The workability and workability are remarkably improved, and a cured product excellent in strength and durability is obtained.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a state of cement particles in an example of the present invention.

FIG. 2 is a diagram schematically showing a state of cement particles according to another embodiment of the present invention.

FIG. 3 is a diagram schematically showing a state of cement particles in a conventional hydraulic material.

FIG. 4 is a diagram schematically showing a state of cement particles in another conventional hydraulic material.

[Explanation of symbols]

11-18 ... Cement particles, 21-26 ... Silica fume

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Yonezawa 2-5-14 Minamisuna, Koto-ku, Tokyo Inside Takenaka Corporation Technical Research Institute (72) Kenro Mitsui 2-chome, Minamisuna, Koto-ku, Tokyo No. 14 Incorporated Takenaka Corporation Technical Research Institute (72) Inventor Kunio Yanagibashi 2-5-14 Minamisuna, Koto-ku, Tokyo Incorporated Takenaka Industrial Engineering Laboratory (72) Inventor Yosaku Ikeo Koto-ku, Tokyo 2-5-14 Minamisuna Technical Research Institute, Takenaka Corp. (72) Inventor Toru Okuno 8-21-1, Ginza, Chuo-ku, Tokyo Incorporated Takenaka Corp. Tokyo Head Office (72) Inventor Etsuro Asakura 1-297 Kitabukuro-cho, Omiya-shi, Saitama Cement Research Institute, Mitsubishi Material Co., Ltd. (72) Kuji Yoshida, 1-297 Kitabukuro-cho, Omiya-shi, Omiya-shi, Saitama Real Co., Ltd. Cement Research Institute (72) Inventor Mitsuo Sato 5-8-20 Konan, Minato-ku, Tokyo Keihin Ryoko Concrete Industry Co., Ltd. Shinagawa Plant (72) Inventor Mitsuo Kinoshita 2-5 Minatomachi, Gamagori City, Aichi Prefecture Takemoto Oil & Fat Co., Ltd.

Claims (4)

[Claims] 1. At least cement and silica fume as a binder, and 1% by weight with respect to the binder as a dispersant.
Less than water-soluble vinyl copolymer, as well as 6 for the binder
A hydraulic material containing 0% by weight or less of water, which is mainly composed of aggregated particles of silica fume having a primary particle size of 0.5 μm or less on all or partial surfaces of cement particles. Further, the volume ratio of the particles having a particle diameter of 1 μm or less in the particles having a particle diameter of 0.1 to 35 μm is 10%.
A hydraulic material comprising the following binder. 2. The hydraulic material according to claim 1, wherein the content of silica fume in the binder is 5 to 35% by weight. 3. Silica fume contains 60% by weight or more of vitreous silica and has a specific surface area of 5-10.
The hydraulic material according to claim 1 or 2, which has a viscosity of 0 m ² / g. 4. A particle in which silica fume is dispersed in water, wherein a volume ratio of particles having a particle diameter of 1 μm or less in all the dispersed particles is 30% or more.
The hydraulic material according to 2 or 3.