JP2016121025A - Hydraulic composition for centrifugal molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic composition, such as concrete and mortar, where a cured body obtained therefrom by centrifugal molding shows sufficient strength.SOLUTION: A hydraulic composition for centrifugal molding comprises water, hydraulic powder, dispersant, aggregate, and persulfate, where the content of persulfate is 0.15 pts.mass or more and 4.3 pts.mass or less based on the hydraulic powder 100 pts.mass.SELECTED DRAWING: None

Description

  The present invention relates to a centrifugal molding hydraulic composition and a method for producing a cured body of the hydraulic composition.

Centrifugal molding is known as a method for producing hollow cylindrical concrete molded articles such as pipes, piles and poles. This centrifugal molding method is a method in which a concrete material kneaded in a mold is put and the concrete is pressed against the inner surface of the mold by a centrifugal force generated by rotating the mold at high speed.
In Japan, when producing a concrete pile that requires high strength, a high-strength admixture is added to the concrete and steam curing is performed in order to ensure the strength that can be shipped in seven days after kneading.

Patent Document 1 describes a process for producing a centrifugal force molded body in which one or two or more selected from oxymonocarboxylic acid and a salt thereof are added in producing a molded body by centrifugal force molding. Describes that by using a high-strength admixture in combination, the centrifugal clamping state is good and high strength can be obtained.
Patent Document 2 describes a high-strength centrifugal force molding concrete composition containing early-strength Portland cement, an admixture containing anhydrous gypsum and amorphous silica under predetermined conditions, a naphthalene-based dispersant, aggregate and water. ing.

Patent Document 3 discloses a Blaine specific surface area of 4000 cm mainly composed of free lime, calcium aluminoferrite and anhydrous gypsum obtained by heat treatment of a CaO raw material, an Al ₂ O ₃ raw material, an Fe ₂ O ₃ raw material and a CaSO ₄ raw material. ^A cement admixture for grouting comprising ² / g or more of an expansion material and a water reducing agent is disclosed, and it is described that the admixture can further contain a peroxide material as a gas foaming material. .
Patent Document 4 discloses 30 to 87% by weight of finely divided granulated slag, 2 to 50% by weight of finely divided slaked lime and / or finely divided quicklime, and a specific water-soluble sulfate such as persulfate. A ground consolidation improver containing 3 to 20% by weight is disclosed.
Patent Document 5 discloses a gypsum board using gypsum and persulfate.

JP 59-207863 A JP 2010-1000050 A JP 2001-163651 A JP 11-293244 A JP 2000-72521 A

  High-strength admixtures are effective in improving the strength of hardened concrete for centrifugal molding. However, if a large amount of high-strength admixture is used, the concrete product after curing will expand or the surface will be cracked at the manufacturing site. It turns out that there is a fear. Further, the use of a high-strength admixture increases the cost. Furthermore, when adding new equipment, it is necessary to invest in silos and measuring instruments. Therefore, there has been a demand for a strength improver that replaces a high-strength admixture, but no replacement has been achieved so far.

  The present invention provides a hydraulic composition such as concrete or mortar in which a cured product obtained by centrifugal molding exhibits sufficient strength.

  The present invention is a centrifugal molding containing 0.15 parts by mass or more and 4.3 parts by mass or less persulfate with respect to 100 parts by mass of water, hydraulic powder, dispersant, aggregate, and hydraulic powder. The present invention relates to a hydraulic composition.

Moreover, this invention relates to the manufacturing method of the hardening body of the hydraulic composition including the following process.
Process 1: Hydraulic composition containing 0.15 mass parts or more and 4.3 mass parts or less persulfate with respect to 100 mass parts of water, hydraulic powder, a dispersing agent, aggregate, and hydraulic powder. Preparing the step.
Step 2: A step of filling the formwork with the hydraulic composition obtained in Step 1.
Step 3: A step of clamping the hydraulic composition filled in the mold in Step 2 by applying centrifugal force.
Step 4: A step of condensing the hydraulic composition clamped in Step 3 in a mold.
Step 5: A step of steam curing the hydraulic composition condensed in Step 4 in a mold.

  Moreover, this invention relates to the dispersing agent composition for hydraulic compositions containing a persulfate and a dispersing agent.

  ADVANTAGE OF THE INVENTION According to this invention, hydraulic compositions, such as concrete and mortar, in which the hardening body obtained by centrifugal molding shows sufficient intensity | strength are provided. The hydraulic composition of the present invention can be used as an indicator of whether or not it can be shipped, for example, by centrifugal molding without using a high-strength admixture, and is important from the viewpoint of cycle time. The cured product after day shows sufficient strength.

  If a high-strength admixture is not used, the produced ettringite is reduced during steam curing, and the strength after 7 days cannot be obtained. Although the mechanism of action of the present invention is unknown, the persulfate can be used in a predetermined amount, so that the persulfate can be gradually decomposed in the hydraulic composition and the sulfate ions can be released gradually, thereby reducing the amount of ettringite. It is thought that it can be suppressed. By setting the persulfate to a predetermined amount, it is considered that a sufficient strength can be obtained by preventing a decrease in filling property due to the toughness of the hydraulic composition, which is a problem particularly during centrifugal molding.

[Hydraulic composition for centrifugal molding]
<Persulfate>
The centrifugal molding hydraulic composition of the present invention contains a persulfate. Examples of persulfate include alkali metal persulfate and ammonium persulfate. The persulfate is preferably one or more compounds selected from sodium persulfate, potassium persulfate, and ammonium persulfate. From the viewpoint of improving the strength for 7 days, sodium persulfate is more preferable.

  The hydraulic composition for centrifugal molding of the present invention contains a persulfate from 0.15 parts by mass to 4.3 parts by mass with respect to 100 parts by mass of the hydraulic powder from the viewpoint of improving the strength for 7 days. This content is preferably 0.3 parts by mass or more, more preferably 0.7 parts by mass or more, further preferably 1.2 parts by mass or more, still more preferably 1.7 parts by mass or more, and 2.1 parts by mass. The above is more preferable, and 2.4 parts by mass or more is even more preferable. Moreover, this content is preferably 3.7 parts by mass or less, more preferably 3.2 parts by mass or less, and even more preferably 2.6 parts by mass or less.

<Dispersant>
The hydraulic composition of the present invention contains a dispersant from the viewpoint of improving fluidity. Examples of dispersants include phosphate ester polymers, polycarboxylic acid copolymers, styrene sulfonic acid polymers, vinyl sulfonic acid polymers, naphthalene polymers, melamine polymers, phenol polymers, lignins. Examples thereof include a dispersant such as a polymer. The dispersant may be an admixture containing other components.

  The dispersant is preferably a naphthalene polymer from the viewpoint of 7-day strength.

  When the dispersing agent is a naphthalene polymer, the centrifugal molding hydraulic composition of the present invention is preferably 0.5 to 100 parts by weight of the hydraulic powder from the viewpoint of 7-day strength. More than mass part, More preferably, it is 0.7 mass part or more, Preferably it is 1.0 mass part or less, More preferably, it contains 0.9 mass part or less.

  The weight average molecular weight of the naphthalene polymer is preferably 1000 or more, more preferably 3000 or more, still more preferably 4000 or more, still more preferably 5000, and preferably 200000 or less, more preferably 100000 or less, still more preferably 80000. Hereinafter, it is more preferably 50000 or less. This weight average molecular weight is measured by gel permeation chromatography (GPC) shown below.

GPC conditions Column: G4000SWXL + G200SWXL (manufactured by Tosoh Corporation)
Eluent: 30 mM CH ₃ COONa / CH ₃ CN = 6/4 (pH = 6.9)
Flow rate: 1.0 mL / min
Column temperature: 40 ° C
Detection: UV (280 nm)
Sample size: 2 mg / mL, 0.01 mL
Standard substance: Polystyrene sulfonic acid equivalent

  Naphthalene polymers can be used in liquid and powder form. Moreover, a commercial item can be used for a naphthalene type polymer, for example, Kao Co., Ltd. Mighty 150 is mentioned.

  Examples of the method for producing a naphthalene polymer include a method of obtaining a condensate by a condensation reaction of naphthalenesulfonic acid and formaldehyde. You may neutralize the said condensate. Moreover, you may remove the water insoluble matter byproduced by neutralization. For example, in order to obtain naphthalenesulfonic acid, 1.2 to 1.4 mol of sulfuric acid is used with respect to 1 mol of naphthalene and reacted at 150 to 165 ° C. for 2 to 5 hours to obtain a sulfonated product. Next, formalin is added dropwise at 85 to 95 ° C. over 3 to 6 hours to form 0.95 to 0.99 mol as formaldehyde with respect to 1 mol of the sulfonated product, and condensed at 95 to 105 ° C. after the addition. Perform the reaction. If necessary, water and a neutralizing agent are added to the condensate, and a neutralization step is performed at 80 to 95 ° C. The neutralizing agent is preferably added in an amount of 1.0 to 1.1 moles per each of naphthalenesulfonic acid and unreacted sulfuric acid. Further, water-insoluble matter generated by neutralization may be removed, preferably separated by filtration. By these steps, an aqueous solution of a naphthalenesulfonic acid formaldehyde condensate water-soluble salt is obtained. This aqueous solution can be used as it is as a naphthalene dispersant. Further, if necessary, the aqueous solution can be dried and pulverized to obtain a powdery naphthalenesulfonic acid formaldehyde condensate water-soluble salt, which may be used as a powdery naphthalene dispersant. Drying and powdering can be performed by spray drying, drum drying, freeze drying, or the like. Although the naphthalenesulfonic acid formaldehyde condensate can be obtained by the above method, the desired product can be obtained under other conditions and methods.

<Hydraulic powder>
The hydraulic powder includes cement. Examples of the cement include various cements such as ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, mixed cement, and eco-cement (for example, JIS R5214). The hydraulic composition for centrifugal molding may include blast furnace slag, fly ash, silica fume and the like as hydraulic powder other than cement.

The hydraulic powder is preferably a hydraulic powder containing a hydraulic powder that hydrates to form ettringite. As a hydraulic powder that hydrates to produce ettringite, calcium aluminate C ₃ A (3CaO · Al ₂ O ₃ ) and / or calcium aluminoferrite C ₄ AF (4CaO · Al ₂ O ₃ · Fe ₂ O ₃ ) Specific examples include ordinary Portland cement, early-strength Portland cement, ultra-early strength Portland cement, moderately hot Portland cement, sulfate-resistant Portland cement, mixed cement, blast furnace cement, silica cement, fly ash cement , Alumina cement, expanded cement and the like. Whether the hydraulic powder hydrates to produce ettringite is determined by the presence of a peak derived from C ₃ A and / or C ₄ AF in the hydraulic powder by powder X-ray analysis (such as Rietveld method). It can be confirmed with.

<Aggregate>
The hydraulic composition for centrifugal molding of the present invention contains aggregate. Examples of the aggregate include fine aggregate and coarse aggregate. The fine aggregate is preferably mountain sand, land sand, river sand and crushed sand, and the coarse aggregate is preferably mountain gravel, land gravel, river gravel and crushed stone. Depending on the application, lightweight aggregates may be used. The term “aggregate” is based on “Concrete Overview” (published on June 10, 1998, published by Technical Shoin).

<Other components and properties of centrifugal molding hydraulic composition>
The hydraulic composition for centrifugal molding of the present invention contains water, hydraulic powder, a dispersant, an aggregate, and a predetermined amount of persulfate. The centrifugal molding hydraulic composition of the present invention can also contain other additives. For example, the following components can be mentioned.
-AE agent: resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, alkylbenzene sulfonic acid or its salt, alkane sulfonate, polyoxyalkylene alkyl (phenyl) ether, polyoxyalkylene alkyl (phenyl) ether sulfate Or salt thereof, polyoxyalkylene alkyl (phenyl) ether phosphate or salt thereof, protein material, alkenyl succinic acid, α-olefin sulfonate, etc., foaming agent, thickener, silica sand, foaming agent, waterproofing material: resin acid Or its salts, fatty acid esters, oils and fats, silicone, paraffin, asphalt, wax, etc., blast furnace slag, fluidizing agents;
-Antifoaming agents: dimethylpolysiloxane, polyalkylene glycol fatty acid esters, mineral oils, fats, oxyalkylenes, alcohols, amides, etc.-Antifoaming agents / rust inhibitors: nitrites, phosphates, zinc oxide Water-soluble polymers: Cellulose type such as methyl cellulose and hydroxyethyl cellulose, natural product type such as β-1,3-glucan and xanthan gum, polyacrylic acid amide, polyethylene glycol, ethylene oxide adduct of oleyl alcohol or vinylcyclohexene Synthetic systems such as reactants with diepoxides, etc. Polymer emulsion: Polymer emulsion using monomers such as alkyl (meth) acrylate

  In the hydraulic composition for centrifugal molding of the present invention, the ratio of the water content to the hydraulic powder content is (water content) / (hydraulic powder content) × 100 (hereinafter referred to as W / P, which is called W / C when the hydraulic powder is cement), preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 35% by mass. Hereinafter, it is more preferably 30% by mass or less. As the value of W / P is smaller, the difference in the effect of improving the smoothness of the inner surface and the appearance of the end surface in the centrifugal molded body becomes more prominent.

  The centrifugal molding hydraulic composition of the present invention has a fine aggregate ratio (s / a) of preferably 30% by volume or more, more preferably 35% by volume or more, and preferably 45% by volume or less, more preferably 40% by volume. % Or less. s / a is calculated by s / a = [S / (S + G)] × 100 (volume%) based on the volume of the fine aggregate (S) and the coarse aggregate (G).

The hydraulic composition for centrifugal molding of the present invention can contain fine aggregate and coarse aggregate. In that case, the fine aggregate is contained in an amount of 450 kg or more, more preferably 550 kg or more, and preferably 950 kg or less, more preferably 750 kg or less with respect to 1 m ^{3 of} uncured concrete (fresh concrete). The coarse aggregate is contained in an amount of 1000 kg or more, more preferably 1050 kg or more, and preferably 1300 kg or less, more preferably 1200 kg or less with respect to 1 m ^{3 of} uncured concrete (fresh concrete).

  The centrifugal composition for centrifugal molding according to the present invention has a slump value of preferably 0 cm or more and 8 cm or less from the viewpoint of reducing lozenges, and improving the filling property of the hydraulic composition into the mold and reducing lozenges. Therefore, it is preferably 0.5 cm or more, more preferably 1 cm or more, and preferably 6 cm or less, more preferably 4 cm or less. The slump value is measured according to JIS A 1101.

The hydraulic composition of the present invention can be used as concrete or mortar.
The hydraulic composition of the present invention is used for producing a cured product by centrifugal molding. In the hydraulic composition of the present invention, since a cured product obtained by centrifugal molding exhibits sufficient strength without using a high-strength admixture, the concern about expansion and cracking of a concrete product can be solved. If necessary, the high-strength admixture and the persulfate according to the present invention can be used in combination.

[Method for producing cured body of hydraulic composition]
The manufacturing method of the hardening body of the hydraulic composition of this invention includes the following process. The matters described in the centrifugal molding hydraulic composition of the present invention can be appropriately applied to the method for producing a cured product of the hydraulic composition of the present invention.
Process 1: Hydraulic composition containing 0.15 mass parts or more and 4.3 mass parts or less persulfate with respect to 100 mass parts of water, hydraulic powder, a dispersing agent, aggregate, and hydraulic powder. Preparing the step.
Step 2: A step of filling the formwork with the hydraulic composition obtained in Step 1.
Step 3: A step of clamping the hydraulic composition filled in the mold in Step 2 by applying centrifugal force.
Step 4: A step of condensing the hydraulic composition clamped in Step 3 in a mold.
Step 5: A step of steam curing the hydraulic composition condensed in Step 4 in a mold.

The manufacturing method of the hardening body of the hydraulic composition of this invention can include the following process 6 and also the process 7.
Process 6: The process of cooling a hydraulic composition after process 5 and demolding from a formwork.
Process 7: The process of curing the hardening body of the hydraulic composition obtained at the process 6 at normal temperature normal pressure.

  In step 1, the method of adding and mixing a mixture containing water, persulfate and a dispersant to the aggregate and the hydraulic powder can be easily and uniformly mixed even when producing the hydraulic composition. preferable.

  As a specific method of Step 1, hydraulic powder and aggregate are mixed, and a mixture containing water, persulfate, and a dispersant is added so as to have the addition amount as described above, and kneaded. And a step of preparing a hydraulic composition.

  The preferable range of the kneading amount of water and persulfate for the hydraulic powder in Step 1 is the same as the preferable range of the content of each component in the centrifugal molding hydraulic composition. In Step 1, W / P, preferably W / C, is preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 35% by mass or less, and still more preferably. It is preferable to prepare a hydraulic composition of 30% by mass or less.

  In step 2, the method of filling the mold with the hydraulic composition obtained in step 1 is a method of discharging the kneaded hydraulic composition from the kneading means and manually putting it into the mold. Can be mentioned.

  In step 3, the hydraulic composition filled in the mold is clamped by applying centrifugal force. At this time, it is preferable to change the centrifugal force at least once. In step 3, the hydraulic composition can be clamped by applying a centrifugal force that changes stepwise.

  In step 3, the hydraulic composition filled in the mold is preferably clamped with a centrifugal force of 0.5 G or more. The centrifugal force of centrifugal molding is preferably 0.5 G or more and 30 G or less, more preferably 25 G or less. From the viewpoint of energy cost reduction and formability, it is preferable to maintain the centrifugal force in a range of 15 G or more, 30 G or less, and further 25 G or less (also referred to as high centrifugal force) for at least 1 minute.

  The compaction with a centrifugal force is, for example, 0.5 G or more and 30 G or less, preferably 5 minutes or more, more preferably 7 minutes or more, still more preferably 9 minutes or more, and preferably 40 minutes or less. From the viewpoint of compacting the molded body smoothly, compaction by holding a high centrifugal force, for example, a centrifugal force of 20 G or more, is preferably 1 minute or more, more preferably 3 minutes or more, still more preferably 5 minutes or more, and preferably Perform for 15 minutes or less.

  Compaction with centrifugal force can be performed in stages, and a method of increasing the centrifugal force G in stages is preferable from the viewpoint of moldability. It can carry out until it becomes a desired centrifugal force on the step conditions as shown below. For example, in the case of five stages, (1) the initial speed of the first stage is 0.5 G or more and less than 2 G with a centrifugal force of more than 0 minutes and less than 15 minutes, and (2) the second speed of the second stage is 2 G or more and less than 5 G. Centrifugal force for more than 0 minutes and 15 minutes or less, (3) Third stage, 3rd speed is 5G or more and less than 10G, and centrifugal force of 0G or more, less than 15 minutes, (4) Fourth stage, 4th speed is 10G or more, 20G It is preferable to carry out with a centrifugal force of less than 0 minutes for 15 minutes or less, and (5) the fifth stage, the fifth speed, with a centrifugal force of 20G to 30G for 0 minutes to 15 minutes or less.

  In step 4, the hydraulic composition obtained in step 3 is condensed. Specifically, air curing is performed for 3 to 4 hours after kneading.

In step 5, the hardened concrete that has entered the mold obtained in step 4 is steam-cured. As curing conditions, it is preferable to perform steam curing at 60 ° C. or more and 85 ° C. or less after performing pre-curing for 1 to 4 hours at room temperature (20 ° C.). Steps 5 and 6 can be performed continuously under a series of temperature controls.
As specific curing conditions, as step 5, the ambient temperature of the mold is raised to 60 ° C. or higher and 85 ° C. or lower at a temperature rising rate of 10 ° C. or higher and 30 ° C. or lower per hour. Hold for 8 hours or less, and then, in step 6, cool to room temperature, for example, 20 ° C., at a temperature drop rate of 5 ° C. or more and 20 ° C. or less per hour, and demold the molded body.
As an example of preferable conditions, it is allowed to stand at room temperature, for example, 20 ° C. for 3 hours, kept at a heating rate of 20 ° C./hour and at 80 ° C. for 6 hours (step 5), and then cooled to room temperature at 10 ° C./hour Then, after 20 hours or more and 30 hours or less, the molded product is removed from the mold (step 6).
Further, it is possible to perform autoclave curing at 180 ° C.

  In step 7, the cured product of the hydraulic composition obtained in step 6 is cured at normal temperature and pressure. Specifically, it is stored at 20 ° C. under atmospheric pressure.

  As a manufacturing method of the hardening body of the hydraulic composition of this invention, the time from starting preparation of a hydraulic composition to demolding in the process 6 is 8 hours or more and 30 hours or less, The manufacturing method of this hardening body is mentioned. Here, the start of the preparation of the hydraulic composition is the time when the hydraulic powder and water first contact each other.

  The cured body of the hydraulic composition obtained by the production method of the present invention can be used as a centrifugal molded concrete product, and specifically includes a pile, a pole, a fume tube, and the like. The cured product of the hydraulic composition obtained by the production method of the present invention is excellent in initial strength and has a low generation amount of noro during production and can reduce waste at the production site of the product. In addition, because it is excellent in compaction, there are few irregularities on the inner surface and end surface of the product, it is excellent in surface aesthetics, and further, the inner surface of the product is finished smoothly, so that obstacles to the cutting machine during pile driving and Nakabori method are improved .

  The present invention relates to a powder for a centrifugal molding hydraulic composition comprising a hydraulic powder and a persulfate of 0.15 parts by mass to 4.3 parts by mass with respect to 100 parts by mass of the hydraulic powder. A composition is provided. This powder composition can be used as a premix cement or the like. Moreover, this powder composition can contain the said dispersing agent. In addition, the matters described in the centrifugal molding hydraulic composition of the present invention can be appropriately applied to this powder composition.

[Dispersant composition for hydraulic composition]
The present invention relates to a dispersant composition for a hydraulic composition containing a persulfate and a dispersant. As the persulfate and the dispersant, those described in the hydraulic composition of the present invention can be used, respectively, and the matters described in the hydraulic composition can be appropriately applied to preferred embodiments.

  In the dispersant composition of the present invention, the mass ratio of persulfate / dispersant is preferably 0.25 or more, more preferably 0.5 or more, and preferably 3.5 or less, more preferably 2.5. It is as follows.

  The dispersant composition of the present invention may be in any form of liquid or solid. In the case of a liquid, it is preferable to contain water. In the case of a liquid, a dispersant composition containing a persulfate, a dispersant and water is preferred. The dispersant composition containing a persulfate, a dispersant and water is preferably 5% by mass or more, more preferably 8% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass. Contain less than mass%. The dispersant composition containing a persulfate, a dispersant and water is preferably 15% by mass or more, more preferably 20% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass. % Or less. The dispersant composition for a hydraulic composition of the present invention can be suitably used for a centrifugal molding hydraulic composition.

<Persulfates and comparative compounds>
Sodium persulfate: manufactured by SIGMA ALDRICH, primary potassium persulfate: manufactured by Kanto Chemical Co., Ltd., special grade, purity 98% excess ammonium sulfate: manufactured by Wako Pure Chemical Industries, Ltd., special grade, purity 98% Super sodium sulfate: Wako Pure Chemical Industries, Ltd. Made, first grade, more than 99% purity <dispersant>
MY150: Naphthalenesulfonic acid formaldehyde condensate: weight average molecular weight 20,000, manufactured by Kao Corporation, Mighty 150 (effective mass 40% by mass), in Table 2, expressed as NSF, indicating the amount of addition in terms of effective mass. The weight average molecular weight was measured by GPC under the above conditions.

Contains mortar

The components in Table 1 are as follows.
W: Wakayama City tap water C: Ordinary Portland cement: Ordinary Portland cement manufactured by Taiheiyo Cement Co., Ltd./Sumitomo Osaka Cement Co., Ltd. Normal Portland cement = 1/1 (mass ratio) mixed cement S: Fine aggregate: Joyo Mountain sand W / C indicates mass% of (content of W) / (content of C) × 100.

Production of mortar Mortar was produced under the blending conditions shown in Table 1. Specifically, using a mortar mixer (all-purpose mixing stirrer model: 5DM-03-γ manufactured by Dalton Co., Ltd.), cement (C) and fine aggregate (S) were added and kneaded for 30 seconds to disperse. Add kneading water (W1) containing the agent and knead for 60 seconds at low speed rotation, add kneading water (W2) containing persulfate or comparative compound, and knead for 240 seconds at low speed rotation for centrifugal molding. Mortar was prepared. The total of the amount of W1 and the amount of W2 is the amount of W in Table 1. Further, the amount of the dispersant was included in the amount of W1, and the amount of persulfate or the comparative compound was included in the amount of W2. In addition, Table 2 shows the effective amount (parts by mass) of persulfate or comparative compound added to 100 parts by mass of cement.
A cured product can be produced by performing Steps 2 to 5 of the present invention, and further Steps 6 and 7 using the obtained mortar for centrifugal molding.

Compressive strength In accordance with JIS A1132, a mortar is filled in a cylindrical plastic mold (bottom diameter: 5 cm, height: 10 cm) by a two-layer packing method. Steam curing was performed at 70 ° C. for 4 hours. Thereafter, it was naturally cooled to room temperature and cured in the air to obtain a cured mortar. Then, after 7 days, for each cured body, the compressive stress of the cured body was measured based on JIS A1108 to determine the compressive strength. These results are shown in Table 2. In Table 2, the strength ratio of the compressive strength is a relative value with the measured value of Comparative Example 1 being 100. The compressive strength obtained here correlates with the compressive strength of the cured product obtained by centrifugal molding.

* 1 parts by mass per 100 parts by mass of cement

  From the results shown in Table 2, it can be seen that in Examples using a predetermined amount of persulfate, sufficient 7-day strength can be obtained without using a high-strength admixture.

Claims (9)

  Hydraulic composition for centrifugal molding containing water, hydraulic powder, dispersant, aggregate, and persulfate of 0.15 parts by mass to 4.3 parts by mass with respect to 100 parts by mass of hydraulic powder. .   The hydraulic composition for centrifugal molding according to claim 1, wherein the hydraulic powder is a hydraulic powder containing a hydraulic powder that hydrates to produce ettringite.   The hydraulic composition for centrifugal molding according to claim 1 or 2, wherein the persulfate is at least one selected from sodium persulfate, potassium persulfate, and ammonium persulfate.   The hydraulic composition for centrifugal molding according to any one of claims 1 to 3, wherein the persulfate is sodium persulfate. The manufacturing method of the hardening body of the hydraulic composition including the following process.
Process 1: Hydraulic composition containing 0.15 mass parts or more and 4.3 mass parts or less persulfate with respect to 100 mass parts of water, hydraulic powder, a dispersing agent, aggregate, and hydraulic powder. Preparing the step.
Step 2: A step of filling the formwork with the hydraulic composition obtained in Step 1.
Step 3: A step of clamping the hydraulic composition filled in the mold in Step 2 by applying centrifugal force.
Step 4: A step of condensing the hydraulic composition clamped in Step 3 in a mold.
Step 5: A step of steam curing the hydraulic composition condensed in Step 4 in a mold.   The manufacturing method of the hardening body of the hydraulic composition for centrifugal molding of Claim 5 whose hydraulic powder is a hydraulic powder containing the hydraulic powder which hydrates and produces | generates an ettringite.   The manufacturing method of the hardening body of the hydraulic composition for centrifugal molding of Claim 5 or 6 whose persulfate is 1 or more types chosen from sodium persulfate, potassium persulfate, and ammonium persulfate.   The manufacturing method of the hardening body of the hydraulic composition for centrifugal molding of any one of Claims 5-7 whose persulfate is sodium persulfate.   A dispersant composition for a hydraulic composition comprising a persulfate and a dispersant.