JPH0834645A - Portland cement for centrifugal forming, hydraulic compound and production of its hardened body - Google Patents

Abstract

PURPOSE:To obtain a high-strength hardened body capable of securing good operability and working time even in an extremely low water/binder ratio without using a high-strength admixture by specifying the hydraulic modulus, Blaine specific surface and residual oversize. CONSTITUTION:80 pts.wt. of a binder as the normal, high-early-strength portland cement having >=2.20 hydraulic modulus and 4000m<2>/g Blaine specific surface and contg. 15-25wt.% residue on 30mum oversize by an air-jet screen, the normal aggregate such as sand and ballast, an aggregate contg. a fine aggregate as the globular aggregate and with the 0.15mm undersize controlled to <=5wt.% and the fine aggregate/binder weight ratio to >=0.20, 0.1-10wt.%, based on 100 pts.wt. of binder, high-performance water reducing agent as the polycarboxylic compd. having 500-50,000 average mol.wt. and <=2.0 pts.wt. of calcium nitrite as the hydration accelerator are mixed, a hardening accelerator, a set accelerator, a reinforcing material, etc., are added, as required, and the mixture is filled or charged in a centrifugal forming device and formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a Portland cement for centrifugal force forming, a hydraulic compound, and a cured product thereof, and particularly for producing centrifugally molded articles such as high-strength concrete poles and concrete piles. The present invention relates to a Portland cement for centrifugal molding, a hydraulic compound, and a method for producing a cured product thereof.

[0002]

^2. Description of the Related Art Conventionally, centrifugal force molded articles such as high strength concrete poles and concrete piles exceeding 800 kgf / cm ² are cured under high pressure and high temperature by an autoclave or an anhydrous salt of calcium sulfate (high strength admixture) is blended. It is manufactured by adjusting concrete, steaming and curing it after centrifugal molding (Japanese Patent Publication No. S57-40105).
Issue). In order to obtain high strength in such a centrifugal force molded product, it is indispensable to reduce the water / binder weight ratio. (Trade name) and Showa Denko KK “Melment” (trade name), etc., the use of naphthalene sulfonic acid-based or melamine sulfonic acid-based high-performance water reducing agents reduces the water / binder weight ratio (water cement ratio 29 ~ 34
%) Is possible, and 800 kgf / cm ^{2 in} about 1 day
The above high-strength PC concrete piles have been obtained.

However, the high-strength centrifugal molded product is obtained by using an expensive high-strength admixture together, and further, the water / binder weight ratio is reduced to obtain an ultra-high-strength cured product. In the case of ordinary Portland cement and early-strength Portland cement that are generally used, especially when the water / binder weight ratio is 0.25 or less and the fine aggregate / binder weight ratio is 0.20 or more, the solid content is significantly increased. It was not possible to secure good workability and sufficient work time, for example, the material separation due to the kneading state or centrifugal force became large, or the phenomenon of fluidity rapidly disappearing with time appeared.

On the other hand, although the manufacturing cost is high, a high-strength cured product can be obtained by performing high-pressure high-temperature curing, but the final strength obtained by high-pressure steam curing is 7 to 8 when performing water curing at 20 ° C. However, it is practically difficult to obtain a compressive strength of 1200 Kgf / cm ² or more unless expensive high-strength admixtures such as anhydrous gypsum and silica fume are used.

[0005]

As described above, a high-strength centrifugal force molded product requires an expensive high-strength admixture, and when only a high-performance water reducing agent is added, an ultra-low water content of 0.25 or less can be obtained.
The water-reducing and fluidizing actions in the weight ratio of the binder are not sufficient, and there is a limit in obtaining an ultra-high-strength cured product by a normal centrifugal molding operation.

It is therefore an object of the present invention to use a water / binder weight ratio of 0.2 without the use of high strength admixtures.
Centrifugal force capable of obtaining a high-strength cured product by ensuring normal workability and sufficient work time even at an ultra-low water / binder ratio of 5 or less, and by ordinary centrifugal force molding work. It is intended to provide a method for producing Portland cement for molding, a hydraulic compound, and a cured product thereof.

[0007]

To achieve the above object, according to the Portland cement for centrifugal molding of the present invention, the hydraulic modulus is 2.20 or more and the Blaine specific surface area is 40.
According to the hydraulic composition for centrifugal molding of the present invention, the binder and the aggregate are characterized in that the residual value on the sieve of 00 cm ² / g or more and the 30 μm sieve is adjusted to 15 to 25% by weight. ,
Contains a high-performance water reducing agent and water, and the binder has a hydraulic modulus of 2.20.
With the above, the Blaine specific surface area of 4000 cm ² / g or more, 30
It is Portland cement adjusted to a residual value on the sieving sieve of 15 to 25% by weight (claim 2), contains a binder, an aggregate, a high-performance water reducing agent, and water, and the binder has a hydraulic modulus of 2.20. With the above, the Blaine specific surface area of 4000 cm ² / g or more, 30μ
80 parts by weight or more of Portland cement adjusted to a residual value on the sieve of 15 to 25% by weight, and a Blaine specific surface area of 1000
Fine aggregate of which particle size is adjusted so that the amount of particles passing through a sieve having a diameter of 0.15 mm is 5% by weight or less, comprising 20 parts by weight or less of ultrafine powder of 0 cm ² / g or more (claim 3). The fine aggregate / binder weight ratio is 0.20 or more (Claim 4), the fine aggregate is a spherical aggregate (Claim 5), and the high-performance water reducing agent is a polycarboxylic acid type. It is a high-performance water reducing agent (Claim 6) and has a water / binder weight ratio of 0.10.
Is 0.25 (claim 7), contains 2.0% by weight or less of a hydration accelerator with respect to 100 parts by weight (claim 8), and the hydration accelerator is calcium nitrite. (Claim 9).

Furthermore, according to the method for producing a centrifugally formed hydraulically cured product of the present invention, a binder, an aggregate, a high-performance water reducing agent,
When centrifugally molding a hydraulic composition containing water and water, the binder has a hydraulic modulus of 2.20 or more and a Blaine specific surface area of 4
000 cm ² / g or more, residual value on sieve of 30 μm 15 to 25
Use of Portland cement adjusted to 10% by weight (claim 10), the binder has a hydraulic modulus of 2.20 or more, a Blaine specific surface area of 4000 cm ² / g or more, and a residual value on the 30 μm sieve of 15 to 25% by weight. 80 parts by weight or more of adjusted Portland cement and a Blaine specific surface area of 10000 cm
20 parts by weight or less of ² / g or more of ultrafine powder (claim 11), steam curing or steam curing and autoclave curing after centrifugal molding (claim 12),
Kneading with a water / binder weight ratio of 0.10 to 0.25 and centrifuging (claim 13), so that the particle size of the aggregate that passes through a 0.15 mm sieve is 5% by weight or less. The adjusted fine aggregate, the fine aggregate / bonding material weight ratio is 0.20 or more (claim 14), the fine aggregate is spherical aggregate (claim 15), and the hydraulic compound. Contains 2.0% by weight or less of a hydration accelerator with respect to 100 parts by weight of the binder (claim 16), and the hydration accelerator is calcium nitrite (claim 17). To do. Hereinafter, the present invention will be described in detail.

In the present invention, the binder is a normal, early strength,
Various portland cements such as super early strength, moderate heat, sulfate resistance, white, etc. can be used, but in consideration of hydration reactivity, fluidity and strength development in a short-term age, the water hardness is 2.20. Thus, Portland cement adjusted so that the Blaine specific surface area is 4000 cm ² / g or more and the residual value on the 30 μm sieve by the air jet type sieving device is 15 to 25% by weight can be preferably used. If the hydraulic modulus is less than 2.20 and the Blaine specific surface area is less than 4000 cm ² / g, sufficient strength development cannot be obtained in a short-term age. Also, 30
The residual value on the μm sieve is in consideration of both fluidity and strength development, and the amount of particles remaining on the 30 μm sieve is 15
Below the weight%, sufficient fluidity cannot be obtained, which is 2
When it exceeds 5% by weight, strength development is lowered and coarse cement particles interfere with fine particles in the fine aggregate, so that fluidity is lowered.

In such Portland cement, in addition to the adjustment of the residual value on the 30 μm sieve, the particle size distribution index value (DI value) obtained by Equation 1 is 0.5 or less, preferably 0.3 or less. By further adjusting the particle size distribution, it is possible to obtain a centrifugally molded product having an extremely excellent fluidity, an ultra-low water / binder ratio, and a higher strength.

[0011]

[Equation 1]

In the formula 1, D ₁₀ , D ₅₀ and D ₉₀ represent particle diameters such that the residue on the sieve becomes 10% by weight, 50% by weight and 90% by weight, respectively, and these particle diameters are 10, 15,
Rosin-Ramula (Ros) was measured between the residual values (% by weight) on each sieve measured by an air-jet type sieving apparatus using 20, 30, 40, 50, 63 and 80 μm electrolytic mesh screens.
in-Rammler) formula is used to calculate the particle size distribution. Formula 1 represents the deviation from the optimum value of the spread of the particle size distribution with respect to fluidity, and the variable D ₉₀ in the formula represents the amount of the fine particle portion in the cement particles that greatly affects the hydration reactivity, and is a variable. D ₁₀ represents the amount of the coarse-grained portion that strongly affects the fluidity due to the interaction with the aggregate described later. As described above, the particle size distribution is adjusted with a classifier or the like so that the DI value becomes 0.5 or less, preferably 0.3 or less.

The above-mentioned binder is made of 20 parts by weight or less of Portland cement and has a Blaine specific surface area of 10,000 cm ²
It can be used by replacing it with an ultrafine powder having an amount of / g or more. The ultrafine powder enhances the fluidity by the bearing effect and makes the hydraulically hardened body dense by the microfiller effect, which greatly contributes to the strength development. When the Blaine specific surface area is less than 10000 cm ² / g, the ultrafine powder cannot sufficiently obtain the bearing effect and the microfiller effect, but when the Blaine specific surface area is 10000 cm ² / g or more, the shape and components are It can be used without limitation, and for example, silica fume, aerosil, calcium carbonate, blast furnace slag, fly ash and the like are preferably used. If the substitution amount of the ultrafine powder for Portland cement exceeds 20 parts by weight, the fluidity is lowered, which is not preferable, and if it is less than 5 parts by weight, almost no effect is obtained.

Next, aggregates include ordinary aggregates such as sand, gravel, and crushed stone used for ordinary mortar and concrete, metal aggregates such as iron and stainless steel, ceramic aggregates such as alumina, and expanded aggregates. It can be used regardless of the type of various aggregates such as lightweight aggregates such as shale. However, considering the fluidity of concrete, the fine aggregate in the aggregate is 0.15m.
It is desirable that the particle size is adjusted so that the particles passing through the m sieve are 5% by weight or less. By adjusting the particle size in this way, it is possible to prevent the fine aggregate particles from interfering with the coarse particles in the cement and obtain good fluidity.

Further, in the aggregate, when spherical aggregates are used as fine aggregates in the above-mentioned particle size adjustment, the fluidity can be remarkably improved, which is very preferable. The spherical aggregate here is usually one obtained by melting metal or ceramics, then scattering and cooling by atmospheric pressure and cooling, and its shape is a rounded spherical shape or something close to it, which constitutes the aggregate. There are no component restrictions.
As this type of spherical aggregate, quenching products of converter slag and blast furnace slag, iron spheres, stainless spheres, glass spheres, ceramic spheres such as alumina and zircon mullite can be preferably used, and fine aggregate / bonding material weight It is used so that the ratio becomes 0.20 or more.

Next, the high-performance water reducing agent used in the present invention includes Kaosha's "Mighty-150" (trade name), Showa Denko's "Melment" (trade name), and Pozoris Bussan's "NL-".
Various known materials such as naphthalene sulfonic acid-based, melamine sulfonic acid-based, lignin sulfonic acid-based, etc. can be used, among others, among which polycarboxylic acid and / or polycarboxylic acid salt as a main component. The carboxylic acid-based high-performance water reducing agent has extremely excellent water reducing and fluidizing effects at an ultra-low water / binder weight ratio of 0.25 or less, and in particular, Portland cement adjusted to have a hydraulic modulus of 0.20 or more as described above. It has excellent compatibility with and has the effect of significantly improving water reduction and fluidity without impairing hydration reactivity in short-term age.

Examples of the polycarboxylic acid-based high-performance water reducing agent include one or more polymers of a carboxyl group-containing polymerizable monomer or an anhydride thereof, or a carboxyl group-containing polymerizable monomer. A compound having a mean molecular weight of 500 to 50,000, which is a polymer of one or more kinds of the isomer or an anhydride thereof and another polymerizable monomer or a salt thereof, is preferably used. Specifically, polyacrylates, polymethacrylates, copolymers of acrylic acid and allyl ether, α
-Copolymers of olefin and ethylenically unsaturated dicarboxylic acid, water-soluble salts such as partially esterified products, partially amidated products and partially imidized products thereof are exemplified, and as typical ones currently marketed,・ SP Company, SP-8 series, HP-1 manufactured by Takemoto Yushi Co., Ltd.
1 series, Work 500 manufactured by Nippon Zeon Co., Ltd., 100PHX manufactured by Denka Grace Co., Ltd. and the like are preferably used, but not limited thereto.

The amount of the high-performance water-reducing agent added is adjusted in consideration of Portland cement for adjusting the particle size, the aggregate, and the required water-reducing effect. %, Preferably 1-5% by weight. If it is less than 0.1% by weight, the water-reducing effect is substantially absent, and if it is added in excess of 10% by weight, the effects of improving the water-reducing property and the fluidity reach a ceiling.

In addition to the above-described compounding ingredients, the present invention also provides various compounding agents and reinforcing materials such as quick-hardening / quick-setting agents, high-strength admixtures, chemical admixtures and the like, which are usually used in cement, mortar and concrete It is also possible to use various fibers and steels. In particular, the addition of calcium nitrite as a hydration accelerator has the effect of enhancing the hydration reaction of Portland cement and shortens the time during which good fluidity can be maintained, but it provides fast hardening, so The strength within can be greatly increased. The amount of calcium nitrite added is preferably 2.0 parts by weight or less with respect to 100 parts by weight of the binder, because the more the amount of calcium nitrite is added, the shorter the time during which fluidity can be maintained.

In the present invention, by combining the above-mentioned binder, aggregate and high-performance water reducing agent, water / water
With an ultra-low water / binder ratio of about 0.15 to 0.25 binder weight ratio, good workability and sufficient work time can be secured, and it is incorporated in a normal centrifugal molding device or pumped. Injection molding can be performed by pressure feeding or the like. As a matter of course, the introduction of prestress is the same as in the past. Also,
In centrifugal molding, there is no limitation on the mixing and kneading method of each of the above components, and any method can be used as long as it can be uniformly mixed and kneaded, but if kneading is performed under the atmospheric pressure in the mixer, it causes a decrease in strength. It prevents air entrainment during kneading and further enables reduction of the water / binder ratio by evaporation of water under reduced pressure. The pressure is preferably 0.5 atmospheric pressure or less, but the effect can be obtained if it is atmospheric pressure or less.
The order of adding the components is not particularly limited.

For the curing after centrifugal molding, various curing methods can be applied, and any of normal temperature curing, high temperature curing, normal pressure steam curing and high temperature and high pressure curing can be adopted. Can be combined to obtain a high-strength hydraulic cured product. In particular, the Portland cement for centrifugal force molding of the present invention and the hydraulic compound thereof are excellent in strength enhancement by steam curing and high temperature and high pressure curing, for example, 800 kg.
In order to obtain a high-strength centrifugal molded product having a strength exceeding f / cm ² , normal pressure steam curing and atmospheric curing after several hours of pre-curing after centrifugal molding are sufficient. In addition, by carrying out high temperature and high pressure curing by an autoclave, it is possible to obtain an ultra-high strength centrifugal molded product of 1500 kgf / cm ² or more. The temperature conditions, pressure conditions and the like for normal pressure steam curing, high temperature and high pressure curing may be within normal ranges.

[0022]

As described above, in order to obtain high strength in mortar, concrete, etc., it is necessary to use a high-strength admixture and reduce the water / binder weight ratio. This invention combines a binder, an aggregate, and a high-performance water reducing agent without using a high-strength admixture, and particularly, has a hydraulic modulus of 2.20 or more and a Blaine specific surface area of 4
000 cm ² / g or more, residual value on sieve of 30 μm 15 to 25
By using Portland cement adjusted to wt%, and further, by combining fine aggregate with a particle size adjusted so that particles that pass through a 0.15 mm sieve will be 5 wt% or less, and a high-performance water reducing agent, Prevention of interference between Portland cement particles and aggregate particles, extremely good compatibility with high performance water reducing agents, etc., these three acts synergistically, water / binder weight ratio of 0.25 or less and fine aggregate / Binder weight ratio of 0.
Under extremely severe conditions of 20 or more, good workability and sufficient work time can be ensured, and a centrifugally molded high-strength hydraulic cured product can be obtained.

[0023]

EXAMPLE As a binder, the hydraulic modulus was 2.22, the Blaine specific surface area was 4230 cm ² / g, and the residual value on the 30 μm sieve was 15.
Portland cement adjusted to 8% by weight, DI value 0.45 (Examples 1 to 6), hydraulic modulus 2.22, Blaine specific surface area 4230 cm ² / g, residual value on sieve of 30 μm 24.6.
Wt%, Portland cement adjusted to a DI value of 0.22 (Example 7), 90 parts by weight of the cement used in Examples 1 to 6 and silica fume as ultrafine powder (Example 8),
Blast furnace slag powder having a Blaine specific surface area of 15600 cm ² / g (Example 9), and Blaine specific surface area of 32400 cm
² / g calcium carbonate powder (Example 10) 1 each
For comparison with a binder made up of 0 parts by weight, a commercially available hydraulic modulus of 2.15 and a Blaine specific surface area of 3360 cm ² / g, 30
Ordinary Portland cement having a residue value on the μm sieve of 23.4% by weight, a DI value of 0.41 (Comparative Examples 1 and 2), and a water hardness of 2.1.
5, using the early strength Portland cement (Comparative Examples 3 to 4) having a Blaine specific surface area of 4390 cm ² / g, a residual value on the sieve of 30 μm of 12.7% by weight, and a DI value of 0.61 at the mixing ratio shown in Table 1. Was adjusted.

As fine aggregate, those having a particle size adjusted to 2.2% by weight of the amount passed through a 0.15 mm sieve (Examples 4 and 6),
Natural Ogasayama sand (excluding Examples 4 and 6) having a content of 5.3% by weight passed under a sieve of 0.15 mm, and a maximum size of 20 m as coarse aggregate.
Mighty-150 (commercial product) manufactured by Kao Corporation, except that Tupole HP-11 (trade name) manufactured by Takemoto Yushi Co., Ltd. was used in Example 5 as the crushed stone from Iwase, a high-performance water reducing agent. First name) was used.

[0025]

[Table 1]

This concrete was placed in a cylindrical centrifugal force forming mold for testing having an inner diameter of 200 mm and a length of 300 mm, and centrifugal force forming was carried out by an ordinary method, and then at room temperature (20
C.) was pre-cured for 4 hours and then steam-cured. In the steam curing, the temperature was raised to 65 ° C. in about 3 hours, kept for 3 hours and 30 minutes, stopped steam, and allowed to cool to room temperature. After demolding, some specimens were subjected to atmospheric curing up to each age and subjected to a compressive strength test, while the remaining specimens were autoclaved immediately after demolding (180 ° C,
After 10 atm for 5 hours, a compressive strength test was performed. The results are shown in Table 1.

[0027]

As described above, according to the present invention,
A high-strength hydraulically hardened product can be formed by ordinary centrifugal molding without using a high-strength admixture, and a water / binder weight ratio of 0.25 or less and a fine aggregate / binder weight ratio of 0 or less. Good workability and sufficient work time can be secured under extremely severe conditions of .20 or more, and an ultra-high strength hydraulically cured product can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C04B 24:26 HE 22:08) B 103: 14 103: 30 111: 56 (72) Inventor Shunichiro Uchida 2-4-2 Daisaku, Sakura City, Chiba Prefecture Central Research Laboratory, Onoda Cement Co., Ltd.

Claims (17)

[Claims] 1. A hydraulic modulus of 2.20 or more, a Blaine specific surface area of 4000 cm ² / g or more, and a 30 μm sieve residue value of 15 to 2
A Portland cement for centrifugal force forming, which is adjusted to 5% by weight. 2. A binder, an aggregate, a high-performance water reducing agent, and water, wherein the binder has a hydraulic modulus of 2.20 or more, a Blaine specific surface area of 4000 cm ² / g or more, and a residual value on a 30 μm sieve of 15 to.
A hydraulic compound for centrifugal molding, which is Portland cement adjusted to 25% by weight. 3. A binder, an aggregate, a high-performance water reducing agent, and water, wherein the binder has a hydraulic modulus of 2.20 or more, a Blaine specific surface area of 4000 cm ² / g or more, and a residual value on a 30 μm sieve of 15 to.
A hydraulic compound for centrifugal molding, which comprises 80 parts by weight or more of Portland cement adjusted to 25% by weight and 20 parts by weight or less of ultrafine powder having a Blaine specific surface area of 10000 cm ² / g or more. 4. An aggregate comprising fine aggregate whose particle size is adjusted so that 5% by weight or less of particles pass through a sieve of 0.15 mm, and a fine aggregate / binder weight ratio is 0.20 or more. The hydraulic compound for centrifugal force molding according to claim 2 or 3, characterized in that. 5. The hydraulic compound for centrifugal molding according to claim 4, wherein the fine aggregate is a spherical aggregate. 6. The hydraulic compound for centrifugal molding according to claim 2, wherein the high performance water reducing agent is a polycarboxylic acid type high performance water reducing agent. 7. A water / binder weight ratio of 0.10 to 0.25.
The hydraulic compound for centrifugal force molding according to any one of claims 2 to 6, wherein 8. A hydration accelerator of 2.0 wt% or less is included with respect to 100 parts by weight of the binder.
7. A hydraulic compound for centrifugal molding according to any one of to 7. 9. The hydraulic compound for centrifugal molding according to claim 8, wherein the hydration accelerator is calcium nitrite. 10. When centrifugally molding a hydraulic compound containing a binder, an aggregate, a high-performance water reducing agent, and water, the binder has a hydraulic modulus of 2.20 or more and a Blaine specific surface area of 4,000.
cm ² / g or more, residual value on sieve of 30 μm 15 to 25% by weight
A method for producing a centrifugally-formed hydraulically cured product, which comprises using the Portland cement prepared as above. 11. When centrifugally molding a hydraulic composition containing a binder, an aggregate, a high-performance water reducing agent, and water, the binder has a hydraulic modulus of 2.20 or more and a Blaine specific surface area of 4000 cm.
It is characterized in that it comprises 80 parts by weight or more of Portland cement adjusted to a residue value on the sieve of ² / g or more and 30 μm sieve of 15 to 25% by weight and 20 parts by weight or less of ultrafine powder having a Blaine specific surface area of 10,000 cm ² / g or more. Method for producing centrifugally molded hydraulically cured product. 12. The method for producing a centrifugally formed hydraulically cured product according to claim 10, wherein steam curing or steam curing and autoclave curing are performed after centrifugal molding. 13. A water / binder weight ratio of 0.10 to 0.2.
5. The mixture is kneaded in 5, and centrifugally molded.
The method for producing a centrifugally formed hydraulically cured product according to any one of 0 to 12. 14. An aggregate comprising fine aggregate whose particle size is adjusted so that the amount of particles passing through a sieve of 0.15 mm is 5% by weight or less, and the fine aggregate / binder weight ratio is 0.20 or more. The method for manufacturing a centrifugally formed hydraulically cured product according to any one of claims 10 to 13. 15. The method for producing a centrifugally-formed hydraulically cured product according to claim 14, wherein the fine aggregate is a spherical aggregate. 16. The centrifugal molding according to claim 10, wherein the hydraulic composition contains 2.0% by weight or less of a hydration accelerator with respect to 100 parts by weight of the binder. A method for producing a hydraulically cured product. 17. The method for producing a centrifugally formed hydraulically cured product according to claim 16, wherein the hydration accelerator is calcium nitrite.