JP5536387B2 - Method for producing centrifugally formed concrete products - Google Patents

Description

  The present invention relates to a method for producing a centrifugally formed concrete product having a step of compacting with a centrifugal force.

  In recent years, the trend toward higher durability of concrete has increased, for example, the amount of water used in centrifugal molded concrete products has been reduced to increase strength, and this trend is expected to increase in the future. Is done. Such concrete has a low amount of water, and the relative water / hydraulic powder ratio in the concrete [weight percentage of water and hydraulic powder in slurry (wt%), usually abbreviated as W / P, Is abbreviated as W / C. Therefore, it has been a technical problem to improve the plasticity and compactness required at the time of centrifugal molding and the inner surface smoothness as a centrifugal molded body.

  Patent Document 1 proposes a method for producing a high-strength centrifugal concrete molding, in which an early-strength cement and a polycarboxylic acid-based admixture are molded and subjected to atmospheric steam curing. Furthermore, Patent Document 2 proposes a method for producing a centrifugally molded concrete product having a step of compacting centrifugally molded concrete containing a specific phosphate ester polymer with a centrifugal force of 0.5 G or more. Patent Document 3 proposes a method for producing a centrifugal molded cured product using a naphthalenesulfonic acid formaldehyde condensate water-soluble salt as a dispersant.

  In the production of centrifugally molded concrete, a retarder such as gluconic acid is used in combination for the purpose of improving workability, but the early strength tends to be reduced by the combined use of the retarder. Patent Document 4 discloses a cement dispersant such as naphthalene sulfonic acid formaldehyde condensate and acrylic acid for the purpose of preventing deterioration in fluidity of concrete and mortar including centrifugal compacted concrete and improving workability and workability. An anti-slump cement dispersing agent having an ester or methacrylate polymer as an essential component has been proposed. However, in order to cope with the recent increase in durability of concrete, there is a demand for a method for producing centrifugally molded concrete that is excellent in workability even in a region where the water / hydraulic powder ratio is lower.

Japanese Patent No. 2887561 JP 2007-137734 A JP 2008-7351 A JP-A-63-161365

  In obtaining centrifugal molded concrete products, the production time (from kneading to placing) is adjusted in consideration of the increase in the size of the product (pile, etc.) and seasonal temperature fluctuations. Even in this case, it is desired that workability and quality (formability, strength, etc.) can be maintained constant.

  An object of the present invention is to provide a method for producing a centrifugal molded concrete product, which is less affected by the production time and can produce a centrifugal molded concrete having a stable quality with good workability.

The present invention relates to a polymer (A) [hereinafter referred to as component (A)] comprising a structural unit containing 70% by weight or more of a structural unit derived from a monomer represented by the following formula (1), and formaldehyde naphthalene sulfonate. A centrifugal molded concrete product comprising a step of compacting a concrete containing a condensate (B) [hereinafter referred to as component (B)], a hydraulic powder, and water with a centrifugal force of 0.5 G or more. It relates to a manufacturing method.
H ₂ C═CHCOOCH ₂ CH ₂ OH (1)

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the centrifugal molding concrete product which is hard to be influenced by manufacturing time and can manufacture the centrifugal molding concrete with stable quality with sufficient workability | operativity is provided.

<(A) component>
(A) A component contributes to fluidity | liquidity fall suppression by progress of the manufacture time of concrete. Component (A) is a polymer in which 70% by weight or more of the structural unit is a structural unit derived from the monomer represented by the above formula (1) [hereinafter referred to as monomer (1)]. The component (A) is 75% by weight or more of the structural unit, more preferably 80% by weight or more, more preferably 85% by weight or more, and still more preferably 90% by weight or more, from the viewpoint of suppressing fluidity deterioration due to the progress of the concrete production time. A structural unit derived from the monomer (1) is preferred. By using together the component (A) in which the proportion of the structural unit derived from the monomer (1) in the structural unit is in this range with the component (B), it is difficult to be affected by the production time, and the quality is stable. Concrete can be manufactured with good workability. In addition, when there exists the salt of the acid or base neutralized in the structural unit of (A) component, the structural unit is converted with the weight of the acid type or base type before neutralization, Formula (1) The weight% of the structural unit derived from the monomer represented by is calculated.

  The weight average molecular weight of the component (A) is preferably 1000 to 100,000, more preferably 3000 to 80000, and further preferably 5000 to 60000, from the viewpoint of the quality stability of the centrifugally shaped concrete with respect to the passage of production time. The weight average molecular weight of the component (A) is measured by using size exclusion chromatography (GPC) and using polystyrene as a RI detector and a calibration substance. The measurement conditions are as in Synthesis Example 1 described later.

  The component (A) can be obtained by a known polymerization method, and the polymerization concentration is preferably 10% by weight or more from an industrial viewpoint. The polymerization method can be performed by a method such as radical polymerization, living radical polymerization, or ionic polymerization, and is preferably a radical polymerization method. The polymerization solvent is not limited as long as the monomer is soluble, but includes water, methyl alcohol, ethyl alcohol, isopropyl alcohol, benzene, toluene, xylene, cyclohexane, n-hexane, ethyl acetate, acetone, methyl ethyl ketone, and the like. Water, methyl alcohol, ethyl alcohol and isopropyl alcohol are preferred.

  As the polymerization initiator, known initiators such as an azo initiator, a peroxide initiator, a macro initiator, and a redox initiator may be used. In the case of a polymerization solvent containing water, as a polymerization initiator, an ammonium salt or alkali metal salt of persulfuric acid, hydrogen peroxide, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis ( Water-soluble azo compounds such as 2-methylpropionamido) dihydrate. In the case of a polymerization solvent not containing water, examples of the polymerization initiator include peroxides such as benzoyl peroxide and lauroyl peroxide, and aliphatic azo compounds such as azobisisobutyronitrile.

  Furthermore, you may use a chain transfer agent for the purpose of a molecular weight modifier etc. as needed. Examples of chain transfer agents include thiol chain transfer agents and halogenated hydrocarbon chain transfer agents, and thiol chain transfer agents are preferred.

As the thiol-based chain transfer agent, those having a -SH group are preferable, and further, a general formula HS-R-Eg (wherein R represents a hydrocarbon-derived group having 1 to 4 carbon atoms, E is —OH, —COOM, —COOR ′ or —SO ₃ M group, M represents a hydrogen atom, monovalent metal, divalent metal, ammonium group or organic amine group, and R ′ has 1 to 10 carbon atoms. Represents an alkyl group, and g represents an integer of 1 to 2). For example, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid , Octyl thioglycolate, octyl 3-mercaptopropionate, etc., from the viewpoint of the chain transfer effect in the copolymerization reaction containing monomers 1 to 3, mercaptopropion , Mercaptoethanol are preferable, more preferably mercaptopropionic acid. These 1 type (s) or 2 or more types can be used.

  Examples of the halogenated hydrocarbon chain transfer agent include carbon tetrachloride and carbon tetrabromide.

  Examples of other chain transfer agents include α-methylstyrene dimer, terpinolene, α-terpinene, γ-terpinene, dipentene, 2-aminopropan-1-ol and the like. A chain transfer agent can use 1 type (s) or 2 or more types.

  The polymerization temperature is not limited, but is preferably controlled in a region up to the boiling point of the polymerization solvent.

  As the component (A), a monomer other than the monomer (1) can be used as a constituent monomer. Examples thereof include (i) monocarboxylic acids such as (meth) acrylic acid and crotonic acid. Furthermore, for example, (ii) dicarboxylic acid monomers such as maleic acid, itaconic acid and fumaric acid, or acid anhydrides thereof may be mentioned. Among these, (meth) acrylic acid, maleic acid and maleic anhydride are preferable, and (meth) acrylic acid is more preferable. The acid or acid anhydride is a salt type such as an alkali metal salt, alkaline earth metal salt, ammonium salt, mono-, di- or trialkyl (carbon number 2 to 8) ammonium salt optionally substituted with a hydroxyl group, or It may be an ester such as an acrylic ester or a methacrylic ester other than the monomer (1). In addition, (meth) acrylic acid means acrylic acid and / or methacrylic acid (hereinafter the same).

<(B) component>
The component (B) is a naphthalenesulfonic acid formaldehyde condensate and contributes to improvement of the fluidity of the concrete immediately after kneading. The component (B) has a weight average molecular weight of preferably 200000 or less, more preferably 100000 or less, still more preferably 80000 or less, and even more preferably 50000 or less from the viewpoint of dispersibility of cement. Further, the weight average molecular weight is preferably 1000 or more, more preferably 3000 or more, further preferably 4000 or more, and more preferably 5000 or more. Therefore, 1000-200000 are preferable, 3000-100000 are more preferable, 4000-80000 are still more preferable, 5000-50000 are still more preferable. The (B) component naphthalenesulfonic acid formaldehyde condensate may be in an acid state or a neutralized product.

  Examples of the method for producing a naphthalenesulfonic acid formaldehyde condensate 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. Specifically, 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 or as a component (B) by appropriately adding other components. Although the solid content concentration of the aqueous solution depends on the application, the component (B) is preferably 30 to 45% by weight. Further, if necessary, the aqueous solution can be dried and powdered to obtain a powdery naphthalenesulfonic acid formaldehyde condensate water-soluble salt, which may be used as the powdery component (B). Drying and powdering can be performed by spray drying, drum drying, freeze drying, or the like.

  In the method for producing a concrete product of the present invention, concrete containing the component (A), the component (B), the hydraulic powder, and water is used. In the concrete, the content of the component (A) is preferably 0.01 to 0.5 parts by weight, more preferably 0.02 to 0.45 parts by weight, and still more 0 to 100 parts by weight of the hydraulic powder. From 0.05 to 0.4 parts by weight is preferable from the viewpoint of slump retention of concrete. In addition, the content of the component (B) in the concrete is preferably 0.1 to 4.0 parts by weight, more preferably 0.2 to 3.5 parts by weight, with respect to 100 parts by weight of the hydraulic powder. Further, 0.4 to 3.0 parts by weight is preferable from the viewpoint of dispersibility of cement.

  Moreover, (A) component is (A) / [(A) + (B)] = 0.01-0.43 with respect to the sum total of (A) component and (B) component, Furthermore, 0.02- The weight ratio is preferably 0.25, and more preferably 0.03 to 0.11, from the viewpoint of dispersibility of cement and slump retention of concrete.

  In addition to this, a dispersant having a structure other than the component (A) and the component (B) may be used in combination. Examples of the dispersant include oxycarboxylic acid or its salt such as sodium gluconate, melamine sulfonate formaldehyde condensate, polycarboxylic acid or ester or salt thereof, purified lignin sulfonic acid or salt thereof, polystyrene sulfonate, phenol Cement dispersant having a skeleton (for example, formaldehyde cocondensate with other monomers copolymerizable with phenolsulfonic acid), cement dispersant having anilinesulfonic acid as a main component (for example, cocondensation with anilinesulfonic acid) (Formaldehyde co-condensates with other possible monomers)) and the like, which are conventionally referred to as concrete admixtures or water reducing agents are preferred, and melamine sulfonate formaldehyde condensates are from the viewpoint of foam stability of fresh concrete More preferably used.

  Further, a polymer obtained by graft polymerization of an ethylenically unsaturated monomer to a polyether compound as described in the claims of JP-A-11-139855 can also be used.

Moreover, in the manufacturing method of the centrifugal-molded concrete of this invention, it is preferable to contain surfactant from a viewpoint of an improvement of a filling property and workability | operativity. Examples of the surfactant include the following compounds (a) to (c), and the following compound (a) is preferable.
Compound (a): Dialkylsulfosuccinate compound (b): An aliphatic hydrocarbon group having 8 or less carbon atoms or an aromatic hydrocarbon group having 18 or less carbon atoms, and a carboxyl group, a sulfonic acid group, a sulfate group, and An anionic compound [compound (I) having at least one polar group selected from phosphoric acid groups, wherein the counter ion of the polar group is a counter ion selected from a hydrogen ion, an alkali metal ion, and an alkaline earth metal ion. )except for〕
Compound (C): Nonionic compound having an alkyl group having 1 to 8 carbon atoms and an oxyalkylene group having an average addition mole number of less than 10 and having a Davis HLB of 7 to 9

  The content of the surfactant is more preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the total amount of the component (A) and the component (B) used in the present invention, from the viewpoint of workability of fresh concrete. 5 to 15 parts by weight is more preferable, and 1 to 10 parts by weight is still more preferable.

  Especially, in the manufacturing method of the centrifugal-molded concrete of this invention, it is preferable to use together the dialkyl sulfosuccinate of a compound (i). By using a dialkyl sulfosuccinate in combination, it is possible to widen the range of slump values at which a cured product with good moldability can be obtained. Examples of the dialkylsulfosuccinate include dialkylsulfosuccinate having an alkyl group having 4 to 12 carbon atoms, preferably 6 to 10 carbon atoms, more preferably 8 to 10 carbon atoms, and the like. From the viewpoint of expanding the range of the slump value in which a hardened body having good moldability can be obtained by reducing the concrete viscosity, dioctyl sulfosuccinate and di-2-ethylhexyl sulfosuccinate are more preferable. Is di-2-ethylhexyl sulfosuccinate. Examples of the salt include ammonium salts and alkali metal salts, alkali metal salts are preferable, and sodium salts and potassium salts are more preferable. The content of the dialkylsulfosuccinate is 0.01 to 0.00 with respect to 100 parts by weight of the hydraulic powder in the concrete containing the component (A), the component (B), the hydraulic powder and water. 5 parts by weight is preferable, and 0.05 to 0.3 part by weight is more preferable.

  Moreover, in the manufacturing method of the centrifugal molding concrete of this invention, an antifoamer can be used together. Antifoaming agents include (1) lower alcohols such as methanol and ethanol, (2) silicones such as dimethyl silicone oil and fluorosilicone oil, and (3) mineral oils such as blends of mineral oil and surfactant. (4) Trialkyl phosphate esters such as tributyl phosphate, (5) Fatty acids or fatty acid esters such as oleic acid, sorbitan oleic acid monoester, polyethylene glycol fatty acid ester, polyethylene glycol / polypropylene glycol fatty acid ester, (6 ) Polyoxyalkylenes such as polypropylene glycol and polyethylene glycol / polypropylene glycol alkyl ether. From the viewpoint of strength, the content of the antifoaming agent is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the total amount of the component (A) and the component (B) used in the present invention, and 0.05 to 5 parts. Part by weight is more preferable, and 0.1 to 3 parts by weight is even more preferable.

  Moreover, in the manufacturing method of the centrifugal molding concrete of this invention, a well-known additive (material) can be used together other than the said surfactant and an antifoamer. For example, AE agent, fluidizing agent, retarding agent, early strengthening agent, accelerator, foaming agent, water retention agent, thickener, waterproofing agent, shrinkage reducing agent, expansion material, water-soluble polymer, silica stone powder , Gypsum, blast furnace slag, fly ash, silica fume and the like.

<Manufacturing method of centrifugal molded concrete product>
In the method for producing centrifugally molded concrete of the present invention, concrete containing component (A), component (B), hydraulic powder, water and the like (hereinafter sometimes referred to as centrifugally molded concrete) is used.

  Hydraulic powder is a powder that has the property of reacting with water and hardening, and a single substance does not have curability, but when two or more types are combined, a hydrate is formed by interaction through water. A powder that hardens and hardens. Examples of the hydraulic powder 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). Centrifugal molded concrete may contain gypsum, blast furnace slag, fly ash, silica fume and the like as hydraulic powder other than cement.

  Centrifugal molded concrete may also contain 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).

  Furthermore, when the thing which has a specific particle size distribution is used as the fine aggregate which comprises centrifugally-molded concrete, the viscosity of the centrifugally-molded concrete of low W / P can further be reduced.

  That is, as fine aggregate of centrifugal molded concrete, the particle size distribution has a passing rate of a sieve having a nominal size of 0.3 mm used in JIS A 1102 (hereinafter referred to as 0.3 mm passing rate) of 1% by weight or more and less than 10% by weight. In addition, it is preferable to use a fine aggregate (hereinafter referred to as fine aggregate A) having a coarse particle ratio of 2.5 to 3.5.

  More preferably, the fine aggregate A has a passing rate in a sieve nominal size exceeding 0.3 mm within the range of the standard particle size distribution.

  In the present invention, the 0.3 mm passage rate of the fine aggregate A is preferably less than 10%, more preferably 9% or less, and even more preferably 7% or less, from the viewpoint of the fluidity of the centrifugally molded concrete. From the viewpoint of material separation resistance of the centrifugally molded concrete, the 0.3 mm passage rate is preferably 1% or more, more preferably 3% or more, and further preferably 5% or more.

  Therefore, from the viewpoint of fluidity maintenance and material separation resistance, the 0.3 mm passage rate is preferably 1% or more and less than 10%, more preferably 3% or more and 9% or less, and further preferably 5% or more and 7% or less. .

  In addition to the above requirements, the fine aggregate A preferably has a coarse particle ratio (JIS A0203-3019) of 2.5 to 3.5, more preferably 2.6 to 3.3, and still more preferably. 2.7 to 3.1. When the coarse particle ratio is 2.5 or more, the viscosity of the concrete is reduced, and when the coarse particle ratio is 3.5 or less, the material separation resistance is also good.

  Further, it is preferable that the passing rate of the fine aggregate A used in JIS A 1102 exceeds a nominal size of 0.3 mm is within the standard particle size range of sand in JIS A 5308 Annex 1 Table 1. More preferably, the passage rate of a sieve having a nominal size of 0.15 mm is less than 2% by weight, and more preferably less than 1.5% by weight. However, from the viewpoint of material separation resistance, it is preferably 0.5% by weight or more. For a sieve having a nominal size of 0.3 mm or more, it is sufficient that one or more nominal sizes have a passing rate within the range of the standard particle size, but preferably all are within the standard particle size range.

  As the fine aggregate A, known materials such as sand and crushed sand can be used in appropriate combination as long as the above particle size distribution and coarse particle ratio are satisfied. Examples of fine aggregates that can be used in the present invention include river sand in specific areas such as Minjiang, Fujian, China. River sand, mountain sand, and crushed sand are preferred to sea sand because they have few pores, low water absorption, and a small amount of water is sufficient to impart the same fluidity. The fine aggregate A preferably has an absolute dry specific gravity (JIS A 0203: number 3015) of 2.56 or more.

  In the concrete used in the present invention, the fine aggregate rate (s / a) is preferably 30 to 45% by volume, and more preferably 35 to 40% by volume. 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 concrete used in the present invention preferably contains fine aggregate and coarse aggregate. The fine aggregate is preferably contained in an amount of 450 to 950 kg and more preferably 550 to 750 kg with respect to 1 m ³ of the uncured hydraulic composition (fresh hydraulic composition). The coarse aggregate is preferably contained in an amount of 1000 to 1200 kg, more preferably 1050 to 1150 kg with respect to 1 m ³ of the uncured hydraulic composition (fresh hydraulic composition).

  Water / hydraulic powder ratio of centrifugally formed concrete [weight percentage (% by weight) of water and hydraulic powder in slurry, usually abbreviated as W / P, but when the powder is cement, W / C Sometimes abbreviated. ] May be 10 to 60% by weight, further 10 to 50% by weight, further 10 to 40% by weight, and further 10 to 35% by weight. As the value of W / P is smaller, the low viscosity characteristic of the centrifugally-molded concrete becomes more prominent, and thus the compaction effect becomes more prominent.

  In the present invention, there is a step of compacting the centrifugally molded concrete with a centrifugal force of 0.5 G or more, preferably 0.5 G to 30 G, more preferably 0.5 G to 25 G, and still more preferably 0.5 G to 20 G. By containing the component (A) and the component (B), it is possible to significantly reduce the manufacturing time constraint. From the viewpoint of energy cost reduction and moldability, it is preferable to maintain the centrifugal force in a range of 15 G to 30 G, further 15 to 25 G, and further 15 to 20 G (also referred to as high centrifugal force) for at least 1 minute.

  The compaction with a centrifugal force is preferably performed, for example, with a centrifugal force of 0.5 to 30 G for 5 to 40 minutes, further 7 to 40 minutes, and further 9 to 40 minutes. From the viewpoint of compacting the molded body smoothly, compaction by holding a high centrifugal force is preferably performed for 1 to 10 minutes, further 3 to 10 minutes, and further 5 to 10 minutes.

  Compaction with centrifugal force can be performed in stages. From the viewpoint of moldability, (1) the initial speed is 0.5 G or more and less than 2 G for 1 to 10 minutes, and (2) the second speed is 2 G. 1 to 10 minutes with a centrifugal force of less than 10 G, (3) 3rd speed for 1 to 10 minutes with a centrifugal force of less than 10G to 20G, and (4) 4th speed for 1 to 10 minutes with a centrifugal force of 20G to 30G. Is preferred.

  Moreover, it is preferable to cure after completion | finish of centrifugal molding. As curing conditions, it is preferable to leave it at room temperature for 1 to 4 hours and perform steam curing. The specific curing condition is that the heating rate is 10 to 30 ° C. and 60 to 85 ° C. per hour, held for 2 to 6 hours, and then naturally cooled to demold the molded body. . As an example of preferable conditions, a method of leaving at room temperature for 2 hours, holding at a temperature rising rate of 18 ° C./hour and holding at 65 ° C. for 4 hours, then naturally cooling and releasing the molded product after 20 hours is mentioned. It is done. Further, it is possible to perform autoclave curing at 180 ° C.

<Centrifuge molded concrete products>
Examples of the centrifugal molded concrete product obtained by the production method of the present invention include a pile, a pole, and a fume tube. Centrifugal concrete products obtained by the production method of the present invention are excellent in compaction, so that both the outer and inner surfaces of the product are less uneven, the surface is aesthetically pleasing, and the inner surface of the product is finished smoothly. The failure of the cutting machine during the Nakabori method is improved.

[Component (A)]
As the component (A), polymers of the following synthesis examples were used.

<Synthetic raw material>
Hydroxyethyl acrylate: Aldrich (96% effective content) [monomer (1)]
Acrylic acid: Aldrich (99% effective)
・ Mercaptopropionic acid: Aldrich
・ Ammonium peroxodisulfate: Wako Pure Chemical Industries, Ltd.

<Synthesis example>
Synthesis example 1
Into a four-necked flask of the reaction vessel, 84.2 g of ion-exchanged water was charged, and after deaeration, a nitrogen atmosphere was established. A monomer liquid was prepared by mixing 20.2 g of acrylic acid (hereinafter referred to as AA) and 83.5 g of hydroxyethyl acrylate (hereinafter referred to as HEA). An initiator aqueous solution (1) was prepared by dissolving 1.3 g of ammonium peroxodisulfate in 26.4 g of ion-exchanged water. 2.6 g of 3-mercaptopropionic acid was dissolved in 25 g of ion-exchanged water to prepare an aqueous chain transfer agent solution. The reaction vessel was brought to 80 ° C., and the monomer solution, the initiator aqueous solution (1) and the chain transfer agent aqueous solution were simultaneously added dropwise over 90 minutes. Thereafter, an aqueous initiator solution (2) obtained by dissolving 0.3 g of ammonium peroxodisulfate in 6.6 g of ion-exchanged water was added dropwise over 30 minutes, and further reacted at 80 ° C. for 60 minutes. After completion of the reaction, the reaction solution was brought to room temperature and neutralized with a 48% aqueous sodium hydroxide solution to obtain an aqueous solution of polymer A-1 having a pH of 5.
Preparation composition ratio:
AA / HEA = 19.5 / 80.5 (weight ratio) (HEA 80.5 wt%)
AA / HEA = 28.0 / 72.0 (molar ratio)
Weight average molecular weight: 34500
AA: 97% reaction rate (HPLC)
HEA: 98% reaction rate (HPLC)
The molecular weight was measured under the following GPC conditions.
[GPC conditions]
Standard material: Polystyrene conversion column: G4000PWXL + G2500PWXL (Tosoh)
Eluent: 0.2M phosphate buffer / acetonitrile = 9/1
Flow rate: 1.0mL / min
Column temperature: 40 ° C
Detector: RI

Synthesis example 2
Into a four-necked flask of the reaction vessel, 85.6 g of ion-exchanged water was charged, and after deaeration, a nitrogen atmosphere was established. A monomer solution was prepared by mixing 11.7 g of AA and 92.1 g of HEA. An initiator aqueous solution (1) was prepared by dissolving 1.3 g of ammonium peroxodisulfate in 25.2 g of ion-exchanged water. An aqueous chain transfer agent solution was prepared by dissolving 2.5 g of 3-mercaptopropionic acid in 25 g of ion-exchanged water. The reaction vessel was brought to 80 ° C., and the monomer solution, the initiator aqueous solution (1) and the chain transfer agent aqueous solution were simultaneously added dropwise over 90 minutes. Thereafter, an aqueous initiator solution (2) obtained by dissolving 0.3 g of ammonium peroxodisulfate in 6.3 g of ion-exchanged water was added dropwise over 30 minutes, and further reacted at 80 ° C. for 60 minutes. After the completion of the reaction, the reaction solution was brought to room temperature and neutralized with a 48% aqueous sodium hydroxide solution to obtain an aqueous solution of pH-5 polymer A-2.
Preparation composition ratio:
AA / HEA = 11.3 / 88.7 (weight ratio) (HEA 88.7% by weight)
AA / HEA = 17.0 / 83.0 (molar ratio)
Weight average molecular weight: 30600
AA: 97% reaction rate (HPLC)
HEA: 98% reaction rate (HPLC)
The measurement conditions for GPC are the same as in Synthesis Example 1.

Synthesis example 3
The reaction vessel was charged with 224.5 g of ion-exchanged water in a four-necked flask, and after deaeration, it was placed in a nitrogen atmosphere. An initiator aqueous solution (1) was prepared by dissolving 4.4 g of ammonium peroxodisulfate in 90 g of ion-exchanged water. A chain transfer agent aqueous solution in which 10.2 g of 3-mercaptopropionic acid was dissolved in 80 g of ion-exchanged water was prepared. The monomer vessel of HEA 280 g, the initiator aqueous solution (1) and the chain transfer agent aqueous solution were dropped simultaneously over 90 minutes at 80 ° C. Thereafter, an initiator aqueous solution (2) obtained by dissolving 0.6 g of ammonium peroxodisulfate in 10 g of ion-exchanged water was dropped over 30 minutes, and further reacted at 80 ° C. for 60 minutes. After completion of the reaction, the mixture was brought to room temperature and neutralized while stirring with a 48% aqueous sodium hydroxide solution. An aqueous solution of polymer A-3 having a pH of 5 was obtained.
Charge composition ratio: HEA 100 mol% (100 wt%)
Weight average molecular weight: 14200
HEA: 96% reaction rate (HPLC)
The measurement conditions for GPC are the same as in Synthesis Example 1.

[(B) component]
As component (B), Mighty 150 [Naphthalenesulfonic acid formaldehyde condensate admixture, manufactured by Kao Corporation] was used. This was designated as B-1.

Examples 1-5 and Comparative Examples 1-3
The dispersants shown in Table 2 were prepared using the above-obtained polymers [component (A)] and component (B) and the like, and evaluation was performed on centrifugal molded concrete having the following composition. The results are shown in Table 2.

(1) Centrifugal molded concrete components and amount

The components in the above composition are as follows.
W: tap water C: early strong cement (Pacific cement), density = 3.14 (g / cm ³ )
SF: Silica fume, density = 2.25 (g / cm ³ )
S: Crushed sand from Tsuchiyama, density = 2.65 (g / cm ³ ), coarse particle ratio = 3.01
G: Crushed stone from Iejima, Hyogo Prefecture, density = 2.63 (g / cm ³ )
W / P = [W / (C + SF)] × 100 (% by weight)
W / C = (W / C) × 100 (% by weight)
s / a = [S / (S + G)] × 100 (volume%)

(2) Preparation Method of Centrifugal Molded Concrete The concrete blending material was kneaded for 3.5 minutes with a forced biaxial mixer to adjust the slump to 2.0 to 4.0 cm. As an antifoaming agent, 0.1% by weight of Foam Rex 797 (manufactured by Nikka Chemical Co., Ltd.) was added with respect to the total amount of the polymer. That is, 0.1 part by weight was added to 100 parts by weight of the total amount of the component (A) and the component (B). The concrete temperature was 35 ° C.

(3) Change in slump with time The concrete was discharged from the mixer, and the slump of each time immediately after preparation, 30 minutes, 60 minutes and 90 minutes was measured according to JIS A1101.

(4) Formability Put 15kg of concrete into a centrifugal mold (φ20cm x height 30cm), initial speed 0.7G x 3 minutes, second speed 5G x 4 minutes, third speed 15G x 2 minutes, fourth speed 25G x 3 Centrifugal compaction was performed for 20 minutes, and 20 ° C. × 3 hr in advance, 18 ° C./hr in temperature increase, 80 ° C. × 8 hr in holding, and then allowed to cool for steam curing. After demolding, the thickness (mm) of the upper and lower portions of the cured body was measured at four locations (total of 8 locations), and evaluated according to the following criteria.
A: The difference between the maximum value and the minimum value of the thickness at 8 locations is less than 3 mm. B: The difference between the maximum value and the minimum value at the 8 locations is 3 mm or more and 5 mm or less. C: The difference between the maximum value and the minimum value of the thickness at 8 locations. Is over 5mm

(5) Compressive strength The compression area was calculated from the average value of the thickness of the cured product used for the evaluation of moldability, the compression stress was measured according to JIS A 1108, and the compression stress / compression area = compression strength was determined.

(Note) The amount of the dispersant added is equivalent to parts by weight in terms of the effective amount relative to 100 parts by weight of the hydraulic powder (the same applies hereinafter). Moreover, X-1 and X-2 are as follows. In Comparative Examples 2 and 3, these are used as the component (A), and the weight ratio and the addition amount are shown. In Example 6 and Comparative Example 4, the amount of component (B) added was increased, and the slump value (immediately after) was made larger than that in Example 1 or the like.
* X-1: “Ultra Gin Na” (manufactured by Borregard, lignin-based admixture)
* X-2: Sodium gluconate

Examples 7 and 8 and Comparative Example 5
In the same manner as in Example 1 and the like, the surfactant obtained as above (mixed with component (A)] and (B) is mixed with a surfactant [component (C)]. Molded concrete was prepared and evaluated. The results are shown in Table 3. In addition, the centrifugal-molded concrete used what increased the addition amount of (B) component, and made the slump value (immediately after) larger than Example 1 grade | etc.,.

(Note) In the table, C-1 is sodium di-2-ethylhexylsulfosuccinate. Moreover, the addition amount of (C) component is a weight part of conversion of an effective part with respect to 100 weight part of hydraulic powder.

  Usually, when the initial slump value of the centrifugally formed concrete is increased, the formability tends to be lowered. However, by comparing the Example 6 in Table 2 with the Example 8 in Table 3, it is carried out by adding the component (C). It can be seen that even if the slump value is larger than in Example 1 or the like, the moldability can be maintained in an excellent state. Therefore, by using the component (C) in combination with the component (A) and the component (B), the slump value can be set in a wide range when producing a centrifugally molded concrete product. That is, even if the fluidity of the concrete changes due to differences in the production lots of cement and aggregates, it becomes possible to reduce fluctuations in the physical properties of the product obtained by using the component (C) together.

Claims (6)

Ri Do from a monomer-derived constitutional unit a structural unit containing 80 wt% or more of the following formula (1), the polymer having a weight average molecular weight is 5000 to 60,000 (A) [hereinafter referred to as the component (A) ], A step of compacting concrete containing naphthalenesulfonic acid formaldehyde condensate (B) [hereinafter referred to as component (B)], hydraulic powder, and water with a centrifugal force of 0.5 G or more. A method for producing a centrifugal molded concrete product.
H ₂ C═CHCOOCH ₂ CH ₂ OH (1)   The weight ratio of the (A) component to the sum of the (A) component and the (B) component in the concrete is (A) / [(A) + (B)] = 0.01 to 0.43. A method for producing a centrifugally-molded concrete product according to 1.   The method for producing a centrifugal molded concrete product according to claim 1 or 2, wherein the content of the component (A) in the concrete is 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the hydraulic powder.   The centrifugally-molded concrete according to any one of claims 1 to 3, wherein the concrete further contains fine aggregate and coarse aggregate, and has a water / hydraulic powder ratio of 10 to 60% by weight. Product manufacturing method.   The method for producing a centrifugal molded concrete product according to any one of claims 1 to 4, further comprising a step of compacting with a centrifugal force at an initial speed of 0.5 G or more and less than 2 G for 1 to 10 minutes.   The method for producing a centrifugally-molded concrete product according to any one of claims 1 to 5, wherein the concrete further contains a dialkylsulfosuccinate.