JP2010030795A - Method for producing concrete product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of performing a molding good in filling property in low vibration even if temperature conditions are varied, and producing a concrete product excellent in early strength and beautiful surface appearance. <P>SOLUTION: When a concrete product is produced from concrete containing a polymer (A) composed of constitutive units containing a constitutive unit derived from a monomer represented by formula (1): H<SB>2</SB>C=CHCOOCH<SB>2</SB>CH<SB>2</SB>OH, in an amount of ≥70 wt.%, a naphthalenesulfonic acid-formaldehyde condensate (B), a hydraulic powder and water, wherein the polymer (A) is contained in an amount of 0.02-0.28 pts.wt. to 100 pts.wt. of the hydraulic powder, the concrete is placed while applying a vibration of ≤10G. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a concrete product.

  When manufacturing concrete products, vibration may be applied using a vibrator (vibrator). Usually, the smaller the fluidity (slump value) of concrete, the more vibration capacity is required. When vibration becomes large, in addition to the problem of noise, problems also arise in terms of the surface appearance of concrete products (such as the generation of water channels). In order to reduce vibration, for example, research has started to increase the fluidity of concrete and eliminate the need for vibrators, but simply adding water or a water reducing agent to increase fluidity causes material separation, Coarse aggregates are entangled and the filling property is deteriorated, and uniform concrete cannot be obtained, resulting in a decrease in strength.

Patent Document 1 proposes a manufacturing method that is effective for surface aesthetics even if the vibration output is reduced. Further, Patent Document 2 proposes a mortar composition that can obtain concrete that can satisfy both filling properties and surface aesthetics at a high level in a concrete product manufactured by vibration molding. Patent Document 3 also discloses that a concrete composition that provides a concrete product with excellent surface aesthetics can be provided by a dispersant containing a polycarboxylic acid polymer and a phosphate ester polymer.
Japanese Patent Laid-Open No. 2001-220195 JP 2001-233655 A JP 2007-210877 A

  Since fluctuations in temperature conditions during the manufacture of concrete products affect the quality of concrete products, it is one of the challenges of the industry to obtain products with stable quality throughout the year. Moreover, when manufacturing concrete products, it is desired that the workability such as filling is excellent even with low vibration. And after satisfying these conditions, it is desired that the obtained concrete product is excellent in early strength (for example, strength after 24 hours) and surface aesthetics. In the said patent document, the point which satisfies all these is not mentioned.

  An object of the present invention is to provide a method capable of producing a concrete product that can be molded with low vibration and good fillability and has excellent early strength and surface aesthetics even when there are variations in production time and temperature conditions. .

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 method for producing a concrete product comprising a step of placing concrete containing a condensate (B) [hereinafter referred to as component (B)], a hydraulic powder, and water under vibration of 10 G or less. In addition, the present invention relates to a method for producing a concrete product, wherein the concrete contains 0.02 to 0.28 parts by weight of the polymer (A) with respect to 100 parts by weight of the hydraulic powder.
H ₂ C═CHCOOCH ₂ CH ₂ OH (1)

  According to the present invention, there is provided a method for producing a concrete product capable of producing a concrete product excellent in early strength and surface aesthetics, which can be molded with low vibration and good fillability even when there are fluctuations in production time and temperature conditions. Provided.

〔concrete〕
In the present invention, (A) component, (B) component, hydraulic powder, and concrete containing water are used. Hereinafter, components and the like used for such concrete will be described.

<(A) component>
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 preferably 75% by weight or more of the structural unit, more preferably 85% by weight or more, and still more preferably 90% by weight or more of the structural unit derived from the monomer (1). By using the component (A) in which the proportion of the structural unit derived from the monomer (1) in the structural unit is in this range in combination with the component (B), flowability can be achieved even with low vibration (for example, vibration acceleration of 10 G or less). Well, it can be filled to every corner. 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.

  (A) As for the weight average molecular weight of a component, 1000-100,000 are preferable, More preferably, it is 3000-80000, More preferably, it is 5000-60000. The component (A) having a weight average molecular weight within this range is suitable for filling with low vibration irrespective of the production time (setting 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 'represents or -SO ₃ M group, M represents a hydrogen atom, a monovalent metal, a divalent metal, an ammonium group or an organic amine group, R' is from 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. For example, (i) monocarboxylic acids such as (meth) acrylic acid and crotonic acid or salts thereof (for example, alkali metal salts, alkaline earth metal salts, ammonium salts, mono-, di-, tri-alkyls in which hydroxyl groups may be substituted) Alkyl (C2-C8) ammonium salt) or esters thereof (for example, acrylic acid esters or methacrylic acid esters other than the monomer (1)). Further, for example, (ii) dicarboxylic acid monomers such as maleic acid, itaconic acid, fumaric acid, or the anhydrides or salts thereof (for example, alkali metal salts, alkaline earth metal salts, ammonium salts, hydroxyl groups are substituted) Mono, di, trialkyl (carbon number 2 to 8) ammonium salt) or ester may be mentioned. Among these, (meth) acrylic acid, maleic acid, and maleic anhydride are preferable, and (meth) acrylic acid or alkali metal salts thereof are more preferable. In addition, (meth) acrylic acid means acrylic acid and / or methacrylic acid (hereinafter the same).

<(B) component>
Component (B) is a naphthalenesulfonic acid formaldehyde condensate, and from the viewpoint of the fluidity of concrete, the weight average molecular weight is preferably 200000 or less, more preferably 100000 or less, still more preferably 80000 or less, and even more preferably 50000 or less. 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.

<Hydraulic powder>
Hydraulic powder is a powder that has the property of curing by reacting with water, and a single substance does not have curability, but when two or more types are combined, a hydrate is formed by interaction through water. It is a powder that hardens and hardens. Examples of the hydraulic powder include ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, mixed cement, and eco-cement (for example, JIS R5214). The concrete used in the present invention may include gypsum, blast furnace slag, fly ash, silica fume, and the like as hydraulic powder other than cement.

<Aggregate>
Moreover, the concrete used for this invention may contain an 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). The concrete used in the present invention preferably contains fine aggregate and coarse aggregate as aggregates.

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

  That is, as a fine aggregate of concrete, the particle size distribution is 1% by weight or more and less than 10% by weight of a screen having a nominal size of 0.3 mm used in JIS A 1102 (hereinafter referred to as 0.3 mm pass rate). And it is preferable to use the fine aggregate (henceforth the fine aggregate A) whose coarse-grain rate is 2.5-3.5.

  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 concrete. From the viewpoint of the material separation resistance of 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 maintaining fluidity and material separation resistance of the concrete, 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. It is.

  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.

<Other ingredients>
The concrete used in the present invention can contain powders other than hydraulic powders for the purpose of preventing material separation or recycling from the environmental aspect. As the powder other than the hydraulic powder, a powder suitable for blending with concrete and suitable for the above purpose is used. Specifically, the powder is selected from calcium carbonate, stone powder, and garbage incineration ash 1 More than seed powders are preferred. The powder other than the hydraulic powder preferably has an average particle size of 0.1 to 200 μm, and more preferably 1 to 100 μm.

  In addition, the concrete used in the present invention includes AE agent, fluidizing agent, retarder, early strengthening agent, accelerator, foaming agent, thickening agent, waterproofing agent, antifoaming agent, shrinkage reducing agent, expansion. Agents, water-soluble polymers, surfactants, and the like.

<Concrete composition, etc.>
In the concrete used in the present invention, the component (A) is 0.02 to 0.28 parts by weight, preferably 0.03 to 0.26 parts by weight, more preferably 0 to 100 parts by weight of the hydraulic powder. 0.05 to 0.20 parts by weight. By containing (A) component in this range, it can be filled with low vibration regardless of the production time (placement time), and the concrete surface has a good appearance.

  Moreover, the concrete used for this invention is 0.1-1.6 weight part of (B) component with respect to 100 weight part of hydraulic powder, Furthermore, 0.2-1.2 weight part, Furthermore, 0 It is preferable to contain 3 to 0.8 parts by weight.

  Moreover, when the concrete used for this invention contains powders other than hydraulic powder, it is 0.1-1. With respect to a total of 100 weight part of hydraulic powder and powder other than hydraulic powder. It is preferable to contain 6 parts by weight, further 0.2 to 1.2 parts by weight, and further 0.3 to 0.8 parts by weight.

  Moreover, in the concrete used for this invention, the weight ratio of (A) component and (B) component is (A) / (B) = 5 / 95-45 / 55, Furthermore, 10 / 90-40 / 60, Further, it is preferably 10/90 to 30/70 from the viewpoint of the fluidity and retention of the concrete.

  Water / hydraulic powder ratio of concrete used in the present invention [weight percentage (% by weight) of water and hydraulic powder in slurry, usually abbreviated as W / P. Sometimes abbreviated as / C. ] 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 concrete becomes more prominent, and the compaction effect becomes more prominent.

The concrete used in the present invention preferably contains fine aggregate and coarse aggregate. In that case, the fine aggregate ratio (s / a) is 35 to 55% by volume, and further 40 to 50% by volume. Is preferred. 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). Further, the fine aggregate is 600 to 800 kg, further 650 to 750 kg, and the coarse aggregate is uncured hydraulic composition (fresh) with respect to 1 m ³ of the uncured hydraulic composition (fresh hydraulic composition). The hydraulic composition in a state) It is preferable to contain 800 to 1200 kg, more preferably 900 to 1100 kg with respect to 1 m ³ .

[Concrete product manufacturing method]
In the present invention, there is a step of placing the specific concrete with a vibration acceleration of a low vibration of 10 G or less. The vibration method used for placing may be any vibration method such as a table, a formwork, the inside, or the surface. If the concrete has high fluidity, it can be placed without vibration. In addition, when a vibration stronger than 10G is applied, the “noise” is intense and lacks in safety, and concrete is separated and a water channel is generated in the product, thereby impairing the commercial value. The vibration acceleration (G) is obtained from 2 [pi ² × (amplitude cm) × (frequency Hz) ^2/981.

[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 (20 ° C.).
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 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-2 having a pH of 5 (20 ° C.).
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 added dropwise 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 (20 ° C.) 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.

[Preparation and evaluation of concrete]
Concrete was prepared using the above components (A) and (B) with the addition amounts shown in Tables 2 and 3 with respect to the components shown in Table 1, and the following evaluations were performed. The results are shown in Tables 2 and 3. The evaluation was performed for concrete temperatures of 30 ° C. and 20 ° C., Table 2 shows the results at a concrete temperature of 30 ° C., and Table 3 shows the results at a concrete temperature of 20 ° C.

The materials used in Table 1 are as follows.
W (water): tap water C (cement): normal Portland cement (ordinary Portland cement manufactured by Taiheiyo Cement Co., Ltd./ordinary Portland cement manufactured by Sumitomo Osaka Cement = 1/1 (weight ratio)), density = 3. 16 (g / cm ³ )
S (fine aggregate): River sand from Yodogawa, Gifu Prefecture, density = 2.60 (g / cm ³ )
G (Coarse aggregate): Crushed stone from Ieyamayama, Hyogo Prefecture, density = 2.60 (g / cm ³ )

(Performance evaluation)
(1) Method for evaluating slump of concrete 30L of the concrete composition shown in Table 1 and all materials, components (A) and (B) in Tables 2 and 3 were charged into a 60 L kneaded biaxial mixer and kneaded for 90 seconds. The slump was measured on the concrete immediately after the completion of kneading and after 30 minutes.

(2) Evaluation method of compressive strength After measuring the 30-minute slump of the concrete prepared in (1), it is filled into a cylindrical plastic mold having an inner diameter of 10 cm and a height of 20 cm in accordance with the use of a JIS A 1132 thrust rod. Then, air curing was performed at the evaluation temperature, and after 24 hours, the mold was removed and the strength was measured. A specimen that was pressed and deformed after 24 hours was evaluated as uncured.

(3) Evaluation method of surface aesthetics After measuring the 30-minute slump of the concrete prepared in (1), it was filled into a steel mold having a length of 10 cm, a width of 20 cm, and a height of 40 cm, and a table vibrator (amplitude 0.15 mm). The vibration accelerations shown in Tables 2 and 3 were loaded with the frequency of), and vibrated for 30 seconds. Two hours after the introduction, the temperature was raised to 18 ° C./hr, the retention was 65 ° C. × 4 hours, and then the steam curing was allowed to cool, followed by demolding after 24 hours. The surface of the specimen (20 × 40 = 800 cm ² ) was observed with the naked eye the number of bubbles (with a particle size of 5 mm or more) and the water channel caused by overdispersion. Was evaluated as a surface aesthetic (noted as “test system” in the table). In addition, the number of bubbles (having a particle size of 5 mm or more) was similarly measured for the concrete to which only the component (B) was added. (B) It means that the reduction effect of a bubble number is excellent, so that the reduction | decrease number of the bubble from the case of only a component is large. Moreover, from the observation result of the state of the water channel, the water channel judgment was evaluated with or without the water channel according to the following criteria.
(Waterway judgment)
A: None B: Very little C: Yes

  In Tables 2 and 3, the added amount is a part by weight as an effective component with respect to 100 parts by weight of the hydraulic powder.

Claims (3)

A polymer (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), a naphthalenesulfonic acid formaldehyde condensate (B), a hydraulic powder, A method for producing a concrete product comprising a step of placing concrete containing water with vibrations of 10 G or less, wherein the concrete contains polymer (A) with respect to 100 parts by weight of hydraulic powder. A method for producing a concrete product comprising 0.02 to 0.28 parts by weight.
H ₂ C═CHCOOCH ₂ CH ₂ OH (1) The method for producing a concrete product according to claim 1, wherein the concrete further contains an aggregate. The method for producing a concrete product according to claim 1 or 2, wherein the weight ratio of the component (A) to the component (B) is (A) / (B) = 5/95 to 45/55.