JPWO2020115790A1 - Additives for hydraulic compositions and hydraulic compositions - Google Patents

Abstract

Provided is an additive for a hydraulic composition having high material separation resistance while mitigating the influence of fine particles and clayey substances contained in an aggregate. It has a structural unit formed from acrylic acid and / or a salt thereof, and has a structural unit consisting of component A having a mass average molecular weight MA of 1000 or more and less than 100,000, and acrylic acid and / or a salt thereof, and has a mass average molecular weight MB. An additive for a water-hard composition and a water-hard composition containing a B component having a mass of 100,000 or more and 50,000,000 or less.

Description

The present invention relates to additives for hydraulic compositions. More specifically, the present invention relates to an additive for a hydraulic composition that can be suitably used for a cement composition or the like, which alleviates the influence of fine particles and clayey substances contained in an aggregate and has high material separation resistance. ..

Conventionally, in order to impart fluidity to a water-hard composition such as mortar or concrete, a lignin sulfonic acid-based dispersant, a naphthalene sulfonic acid-based dispersant, a melamine sulfonic acid-based dispersant, etc. Polycarboxylic acid-based dispersants and the like are used. In recent years, there have been many opportunities to use hydraulic compositions having further improved fluidity in order to improve filling property, labor saving, and workability. As such a hydraulic composition, for example, high-fluidity concrete having a slump flow of about 500 to 700 mm and medium-fluidity concrete having a slump flow of about 350 to 500 mm are used.

Various techniques have been proposed to obtain such hydraulic compositions. For example, in Patent Document 1, by using an admixture containing a specific polycarboxylic acid-based dispersant and a copolymer of a carboxylic acid monomer and a (meth) acrylic acid-based ester, the concrete is fluidized. It has been proposed that material separation resistance can be imparted. Then, Patent Document 1 describes a one-component admixture in which a specific polycarboxylic acid-based dispersant, which is a raw material component, and a copolymer of a carboxylic acid monomer and a (meth) acrylic acid-based ester are combined. It is disclosed that it can be supplied as.

Further, Patent Document 2 proposes that concrete having high filling property and high fluidity can be obtained by using a specific low-substituted hydroxypropyl cellulose.

Japanese Unexamined Patent Publication No. 2001-89212 Japanese Unexamined Patent Publication No. 4-139047

Coarse aggregates, fine aggregates and the like are used as the aggregates to be blended in the hydraulic composition. As these coarse aggregates and fine aggregates, natural aggregates such as gravel and sand produced from rocks by natural action and produced from rivers, mountains, seas and land, and rocks are artificially crushed with a crusher or the like. The crushed stone and crushed sand obtained from the above are used.

While high-quality natural aggregate is being depleted, in consideration of resource conservation and the impact on the environment during cleaning, fine particles and clay that adhere to natural aggregate are within the permissible range of quality. May be used without washing off.

In some cases, crushed stone and crushed sand with fine particles and clay attached when rock is artificially crushed to produce crushed stone and crushed sand are used.

If these fine particles and clay remain attached to the aggregate, it is necessary to increase the amount of the dispersant added. There is a problem that bleeding occurs more when the amount of the dispersant added is increased. Further, there is a problem that the material is easily separated when trying to obtain a hydraulic composition having a predetermined slump flow and high fluidity.

The composition of aggregate differs depending on the place and time of collection, and the quality also differs. There are problems that the fluidity of the hydraulic composition is not constant due to the difference in composition and quality of the aggregate, and that it is necessary to change the amount of the admixture added in order to obtain a predetermined fluidity.

Further, when hydroxypropyl cellulose having a low degree of substitution is used, there is a problem that the compatibility with the water reducing agent component is low and it cannot be liquefied as an aqueous solution.

The techniques disclosed in Patent Documents 1 and 2 have not been able to solve these problems. Therefore, the problem to be solved by the present invention is to alleviate the influence of the fine particles and the clay material contained in the aggregate even if the fine particles and the clay material attached to the aggregate are not washed away. Further, it is an object of the present invention to provide an additive for a hydraulic composition having high material separation resistance.

As a result of research to solve the above-mentioned problems, the present inventors have found that it is correct and suitable to use an additive for a hydraulic composition having a specific polymer. According to the present invention, the following additives for hydraulic composition are provided.

[1] An additive for a hydraulic composition containing the following component A and the following component B.
Component A has a structural unit formed from acrylic acid and / or salt thereof, the weight-average molecular weight _{M A} is less than 1000 to 100,000 polymer;
Component B has an acrylic acid and / or structural units from the salt, the weight-average molecular weight _{M B} is 100000 50000000 less polymer;

[2] The additive for a hydraulic composition according to the above [1], wherein the mass ratio A: B of the component A to the component B is 1:99 to 99: 1.

[3] The additive for a hydraulic composition according to the above [1], which further contains a carboxylic acid-based copolymer as a C component.

[4] The additive for a hydraulic composition according to the above [3], wherein the total mass% of the A component and the B component is 0.1 to 25% with respect to the mass of the C component.

[5] A hydraulic composition containing the additive for a hydraulic composition according to any one of the above [1] to [4].

[6] Further, the hydraulic composition according to the above [5], which contains a binder.

[7] The hydraulic composition according to the above [6], wherein the total mass part of the A component and the B component is 0.00005 to 0.04 parts by mass with respect to 100 parts by mass of the binder.

According to the additive for hydraulic composition of the present invention, the influence of the fine particles and the clay material contained in the aggregate is alleviated even if the fine particles and the clay material attached to the aggregate are not washed away. At the same time, it has the effect of increasing the material separation resistance.

Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments. Therefore, it should be understood that the following embodiments can be appropriately modified, improved, or the like based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. In the following examples and the like, unless otherwise specified,% means mass% and parts means parts by mass.

The additive for a hydraulic composition of the present embodiment is an additive for a hydraulic composition containing a component A and a component B.

The components A and B used in the additive for the hydraulic composition of the present embodiment are polymers having a structural unit formed of acrylic acid and / or a salt thereof. Here, the type of acrylate is not particularly limited, but for example, an alkali metal salt such as a sodium salt or a potassium salt, an alkaline earth metal salt such as a calcium salt or a magnesium salt, an ammonium salt, or a diethanolamine salt. And amine salts such as triethanolamine salts. From the viewpoint of ease of handling and availability, sodium salts and ammonium salts are preferable, and sodium salts are more preferable. Further, acrylic acid and / or a salt thereof may be only one kind or two or more kinds.

Polymer of component A to be subjected to hydraulic compositions for additives of the present embodiment, the weight average molecular weight _{M A} is less than 1000 to 100,000, preferably at 1000 to 50,000, it is 1000 to 30,000 Is more preferable, and more preferably 1000 or more and 10000 or less.

Polymer B component subjected to hydraulic compositions for additives of the present embodiment, the weight average molecular weight _{M B} is is 100000 or 50000000 or less, is preferably 300,000 or more 30 million or less, is 500,000 or more 20000000 less Is more preferable, and more preferably 800,000 or more and 10,000,000 or less.

In the additive for a water-hard composition of the present embodiment, the concentrations of the A component and the B component are not particularly limited, but if the ratio of the A component is too high, a sufficient separation suppressing effect cannot be obtained, and the B component is not obtained. From the viewpoint of preventing the fluctuation of the fluidity of the water-hard composition due to the fine particles in the aggregate from becoming large when the ratio of A: B is too high, the mass ratio A: B of the component A and the component B is 1: It is preferably 99 to 99: 1, more preferably 50:50 to 99: 1, further preferably 75:25 to 99: 1, and preferably 80:20 to 99: 1. Even more preferably, it is particularly preferably 80:20 to 96: 4.

The additive for the hydraulic composition of the present embodiment further preferably contains a carboxylic acid-based copolymer as the C component.

As the carboxylic acid-based copolymer of component C to be used as the additive for the water-hard composition of the present embodiment, a structural unit formed from an unsaturated carboxylic acid monomer and / or a salt thereof, and 1 to 300 in the molecule. Examples thereof include those having a structural unit formed from an unsaturated monomer having a polyoxyalkylene group composed of oxyalkylene units having 2 to 4 carbon atoms.

Examples of the unsaturated carboxylic acid monomer and / or a salt thereof include (meth) acrylic acid, crotonic acid, (maleic anhydride) maleic acid, (anhydrous) itaconic acid, fumaric acid and / or a salt thereof. The unsaturated dicarboxylic acid monomer having two or more carboxyl groups in one molecule may have an ester bond, an amide bond, or the like in addition to one carboxylic acid or a salt thereof. Here, the type of unsaturated carboxylate is not particularly limited, and for example, an alkali metal salt such as a sodium salt or a potassium salt, an alkaline earth metal salt such as a calcium salt or a magnesium salt, an ammonium salt, a diethanolamine salt or a triethanolamine. Examples include amine salts such as salts.

Examples of the unsaturated monomer having a polyoxyalkylene group composed of 1 to 300 carbon atoms 2 to 4 oxyalkylene units in the molecule include α-vinyl-ω-hydroxy (poly) oxybutylene (. Poly) oxyethylene, α-allyl-ω-methoxy- (poly) oxyethylene, α-allyl-ω-methoxy- (poly) oxyethylene (poly) oxypropylene, α-allyl-ω-hydroxy- (poly) oxy Ethylene, α-allyl-ω-hydroxy- (poly) oxyethylene (poly) oxypropylene, α-metharyl-ω-hydroxy- (poly) oxyethylene, α-metharyl-ω-methoxy- (poly) oxyethylene, α -Metalyl-ω-hydroxy- (poly) oxyethylene (poly) oxypropylene, α-metharyl-ω-acetyl- (poly) oxyethylene, α- (3-methyl-3-butenyl) -ω-hydroxy- (poly) ) Oxyethylene, α- (3-methyl-3-butenyl) -ω-butoxy- (poly) oxyethylene, α- (3-methyl-3-butenyl) -ω-hydroxy- (poly) oxyethylene (poly) Oxypropylene, α- (3-methyl-3-butenyl) -ω-acetyl- (poly) oxyethylene (poly) oxypropylene, α-acryloyl-ω-hydroxy- (poly) oxyethylene, α-acryloyl-ω- Methoxy- (poly) oxyethylene, α-acryloyl-ω-butoxy- (poly) oxyethylene, α-acryloyl-ω-methoxy- (poly) oxyethylene (poly) oxypropylene, α-methacryloyl-ω-hydroxy-( Poly) oxyethylene, α-methacryloyl-ω-methoxy- (poly) oxyethylene, α-methacryloyl-ω-butoxy- (poly) oxyethylene, α-acryloyl-ω-methoxy- (poly) oxyethylene (poly) oxy Propropylene, α-methacryl-ω-hydroxy- (poly) oxyethylene (poly) oxypropylene, α-methacryl-ω-acetyl- (poly) oxyethylene (poly) oxypropylene, active imino group of polyalkylene polyamine, active amino A polyalkylene polyamine-based monomer having an unsaturated bond such as a (meth) acryloyl group in the molecule with an alkylene oxide added to the group, and an active imino group of a polyamide polyamine obtained by condensing a dibasic acid and a polyalkylene polyamine. , Amino group, alkylene ok for amide residues Examples thereof include polyamide polyamine-based monomers having a sid added and having an unsaturated bond such as a (meth) acryloyl group in the molecule.

The mass average molecular weight of the carboxylic acid-based copolymer as the C component is preferably 2000 to 500,000, more preferably 5000 to 20000.

In the additive for hydraulic composition of the present embodiment, the total mass% of the A component and the B component is preferably 0.1 to 25%, preferably 0.2 to 15%, based on the mass of the C component. It is more preferably 0.3 to 10%, and even more preferably 0.5 to 5%.

Next, the hydraulic composition of the present embodiment will be described. The hydraulic composition of the present embodiment contains the additive for the hydraulic composition of the present embodiment.

As a method of adding the additive for the hydraulic composition to the hydraulic composition, the component A, the component B, and the component C may be added independently or at the same time. The A component, the B component, and the C component may be added to the water-hard composition slurry as a powder, or the A component, the B component, and the C component are dispersed in a liquid shrinkage reducing agent, a liquid defoaming agent, or the like. It may be added to the water-hard composition slurry in a state of being dissolved or in a dissolved state, and further, the component A, the component B and the component C may be added to the water-hard composition slurry in a state of being dissolved in water. The addition mode of each component may be different. For example, the A component and the B component may be added as a powder, and the C component may be added in a state of being dispersed in a liquid shrinkage reducing agent, a liquid defoaming agent, or the like, or other addition modes may be used.

The carboxylic acid-based copolymer as the C component may be used as an aqueous solution, and when used as an aqueous solution, the pH of the 1% by mass aqueous solution of the C component is 2 to 2 from the viewpoint of compatibility between the A component and the B component. It is preferably 7, more preferably 2 to 6, and even more preferably 2 to 5.

The hydraulic composition of the present embodiment is prepared by using the additive for the hydraulic composition of the present embodiment as described above, and may be a cement composition such as cement paste, mortar, or concrete. preferable. The cement composition uses at least cement as a binder, but cement may be used alone, or a pozzolanate or a fine powder admixture having latent hydraulic property may be used in combination with cement. good. Such cements include ordinary Portland cement, moderate heat Portland cement, low heat Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, various Portland cements such as sulfate-resistant Portland cement, blast furnace cement, and fly ash cement. Various mixed cements can be mentioned. Examples of the fine powder admixture include blast furnace slag fine powder, silica fume, fly ash, and limestone fine powder. Further, it may contain a swelling material, gypsum and the like.

The hydraulic composition of the present embodiment preferably contains an aggregate. As the aggregate, any suitable aggregate such as fine aggregate or coarse aggregate can be adopted. Among such aggregates, fine aggregates include river sand, mountain sand, land sand, silica sand, crushed sand, blast furnace slag fine aggregate, and coarse aggregates include river gravel, mountain gravel, and land gravel. , Crushed stone, blast furnace slag coarse aggregate, etc.

In the water-hardening composition of the present embodiment, the total mass part of the A component and the B component is preferably 0.00005 to 0.04 parts by mass with respect to 100 parts by mass of the binder, and 0.0002 to 0. It is more preferably 03 parts by mass, further preferably 0.0002 to 0.02 parts by mass, further preferably 0.0003 to 0.01 parts by mass, and 0.0004 to 0.008 parts by mass. It is particularly preferable that it is by mass.

The water-hard composition of the present embodiment is appropriately prepared as long as the effect is not impaired, as appropriate, for example, an AE modifier composed of an anionic surfactant, for example, an oxyalkylene-based antiseptic, for example, an oxycarboxylic acid salt. A setting retarder consisting of, for example, a curing accelerator made of alkanolamine, for example, a drying shrinkage reducing agent made of polyoxyalkylene alkyl ether, for example, a preservative made of an isothiazolin-based compound, for example, a waterproofing agent made of a higher fatty acid derivative. For example, a rust preventive made of nitrite or the like can be contained.

Hereinafter, examples and the like will be given in order to make the configuration and effect of the present invention more specific, but the present invention is not limited to the examples. In the following examples, unless otherwise specified,% means mass% and parts means parts by mass.

Test Category 1 (Polymer of acrylic acid and / or its salt as component A and component B)
The polymers of acrylic acid and / or salts thereof used are summarized in Table 1.

In Table 1,
A-1: Sodium polyacrylate (Aron T-210 manufactured by Toagosei Co., Ltd.)
A-2: Polyacrylic acid (5,000 polyacrylic acid manufactured by Wako Pure Chemical Industries, Ltd.)
A-3: Polyacrylic acid (polyacrylic acid 25,000 manufactured by Wako Pure Chemical Industries, Ltd.)
B-1: Polyacrylic acid (polyacrylic acid 250,000 manufactured by Wako Pure Chemical Industries, Ltd.)
B-2: Polyacrylic acid (Polyacrylic acid manufactured by Wako Pure Chemical Industries, Ltd. 1,000,000)
B-3: Sodium polyacrylate (Aron A-20P-X manufactured by Toagosei Co., Ltd.)
R-1: Hydroxypropyl methylcellulose (Metro's Hi90SH30000 manufactured by Shin-Etsu Chemical Co., Ltd.)
R-2: Hydroxypropyl methylcellulose (Metro's Hi90SH100000 manufactured by Shin-Etsu Chemical Co., Ltd.)
d-1: Constituent unit formed from sodium acrylate d-2: Constituent unit formed from acrylic acid d-3: Constituent unit formed from acrylic acid d-4: Constituent unit formed from acrylic acid d -5: Constituent unit formed from acrylic acid d-6: Constituent unit formed from sodium acrylate

Test Category 2 (Production of Carboxylic Acid Copolymer as C Component)

-Production Example 1 {Production of carboxylic acid-based copolymer (PC-1)}
A reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, and a nitrogen introduction tube containing 250 g of distilled water and 330 g of α- (3-methyl-3-butenyl) -ω-hydroxy-poly (n = 50) oxyethylene (hereinafter, (A similar one was used), and after uniformly dissolving with stirring, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was maintained at 65 ° C. in a warm water bath. Next, 16 g of 1% hydrogen peroxide solution was added dropwise over 3 hours, and at the same time, an aqueous solution in which 30 g of acrylic acid was uniformly dissolved in 80 g of ion-exchanged water was added dropwise over 3 hours, and at the same time, it was added to 14 g of ion-exchanged water. An aqueous solution prepared by dissolving 2 g of L-ascorbic acid and 3 g of thioglycolic acid was added dropwise over 4 hours. Then, the temperature of the reaction system was maintained at 65 ° C. for 2 hours to complete the polymerization reaction. Then, a 30% aqueous sodium hydroxide solution was added to the reaction system to adjust the pH to 3, and the concentration was adjusted to 40% with ion-exchanged water to obtain a reaction mixture. When this reaction mixture was analyzed by gel permeation chromatography (GPC), it had a mass average molecular weight of 35,000. This reaction product was designated as a carboxylic acid-based copolymer (PC-1).

-Production Example 2 {Production of Carboxylic Acid Copolymer (PC-2)}
150 g of distilled water was charged into the reaction vessel, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was maintained at 60 ° C. under the nitrogen atmosphere. Next, 150 g of distilled water, 20 g of methacrylic acid, 320 g of α-hydroxy-ω-methacryloyl-poly (n = 2) propylene poly (n = 113) oxyethylene, 10 g of hydroxyethyl acrylate, and 3.5 g of 3-mercaptopropionic acid were added. The mixture was uniformly mixed to prepare an aqueous solution of a monomer mixture. A radical copolymerization reaction was carried out by simultaneously dropping 24 g of this monomer mixture aqueous solution and 24 g of a 10% sodium persulfate aqueous solution into a reaction vessel over 4 hours, and further, 6 g of a 10% sodium persulfate aqueous solution was added dropwise over 1 hour. And reacted. Then, the temperature of the reaction system was maintained at 60 ° C., and the radical copolymerization reaction was carried out for 1 hour. Then, after cooling the reaction system to room temperature, an aqueous sodium hydroxide solution was added to adjust the pH to 5, and the concentration was adjusted to 40% with distilled water to obtain a reaction mixture. When this reaction mixture was analyzed by gel permeation chromatography (GPC), it had a mass average molecular weight of 43000. This reaction mixture was designated as a carboxylic acid-based copolymer (PC-2).

-Production Example 3 {Production of Carboxylic Acid Copolymer (PC-3)}
150 g of distilled water was charged into the reaction vessel, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was maintained at 60 ° C. under the nitrogen atmosphere. Next, 150 g of distilled water, 35 g of methacrylic acid, 300 g of α-methoxy-ω-methacryloyl-poly (n = 23) oxyethylene, 5 g of methyl acrylate, and 3.5 g of 3-mercaptopropionic acid were uniformly mixed to form a monomer. Aqueous mixture was prepared. A radical copolymerization reaction was carried out by simultaneously dropping 24 g of this monomer mixture aqueous solution and 24 g of a 10% sodium persulfate aqueous solution into a reaction vessel over 4 hours, and further, 6 g of a 10% sodium persulfate aqueous solution was added dropwise over 1 hour. And reacted. Then, the temperature of the reaction system was maintained at 60 ° C. and a radical copolymerization reaction was carried out for 1 hour. Then, after cooling the reaction system to room temperature, an aqueous sodium hydroxide solution was added to adjust the pH to 4, and the concentration was adjusted to 40% with distilled water to obtain a reaction mixture. When this reaction mixture was analyzed by gel permeation chromatography (GPC), it had a mass average molecular weight of 43000. This reaction mixture was designated as a carboxylic acid-based copolymer (PC-3).

Test category 3 (Measurement of mass average molecular weight of component A and component B)
The mass average molecular weights of the A component and the B component were measured by the following methods. The results are shown in Table 1.

[Measurement of mass average molecular weight of component A and component B]
The mass average molecular weight of the polymer of acrylic acid and / or a salt thereof is measured by gel permeation chromatography-multiangle light scattering method (GPC-MALS method) and / or gel permeation chromatography method (GPC method). The conditions were as follows. The polymers of acrylic acid and / or salts thereof used are shown in Table 1.
When the mass average molecular weight of polyacrylic acid exceeded 500,000, it could not be measured by the GPC method. Therefore, the GPC-MALS method was used for those having a mass average molecular weight exceeding 500,000. In B-1, the difference in molecular weight between the GPC-MALS method and the GPC method was within ± 3% and was considered to be the same.
[Measurement condition]
[GPC-MALS method]
Detectors: Differential Refractometer (RI), Multi-angle Light Scattering Detector (MALS)
Column: Showa Denko OHpak SB-807 HQ + SB-806M HQ
Eluent: 0.1 M Tris buffer (pH = 0.9, 0.1 M potassium chloride added) / acetonitrile mixed solvent (mixed volume ratio: 7/3)
Flow rate: 0.5 mL / min Column temperature: 40 ° C
[GPC method]
Detector: Differential Refractometer (RI)
Column: Showa Denko OHpak SB-G + SB-806M HQ + SB-806M HQ
Eluent: 50 mM sodium nitrate aqueous solution Flow rate: 0.7 mL / min Column temperature: 40 ° C
Standard substance: Agilent's sodium polyacrylate

[Measurement of mass average molecular weight of C component]
The mass average molecular weight of the carboxylic acid-based copolymer as the C component was measured by gel permeation chromatography (GPC), and the conditions were as follows.

[Measurement condition]
Detector: Differential Refractometer (RI)
Column: Showa Denko OHpak SB-G + SB-806M HQ + SB-806M HQ
Eluent: 50 mM sodium nitrate aqueous solution Flow rate: 0.7 mL / min Column temperature: 40 ° C
Standard material: Polyethylene glycol / oxide (PEG / PEO) manufactured by Agilent.

Test category 4 (confirmation of compatibility)
The compatibility of the solution was sufficiently stirred and mixed at the ratio of the A component and the B component shown in Table 2 when the carboxylic acid-based copolymer of the C component was 20%, and the compatibility was visually determined according to the following criteria. Tap water was used to adjust the concentration of the solution.
(Criteria for compatibility)
A: Precipitation and sedimentation could not be discriminated B: Light turbidity was confirmed C: Precipitation and sedimentation were confirmed

In Table 2,
* 1: It was used so that the mass ratio of B-2: B-3 was 50:50.
* 2: R-1 and R-2 were replaced with B component and added.

Test Category 5 (Preparation of Concrete Composition as Hydraulic Composition)
The concrete composition was prepared as follows under the compounding conditions shown in Tables 2 and 3. 50L pan-type forced kneading mixer, ordinary Portland cement (density 3.16 g / cm ³ ), fly ash (density 2.29 g / cm ³ , strong heat loss 2.3%), blast furnace slag fine powder (density 3.16 g / cm 3), blast furnace slag fine powder (density 3.16 g / cm 3) density 2.88 g / cm ³⁾ was charged, as a fine aggregate Oi aqueous production Rikusuna (density 2.58 g / cm ³⁾ and Okazaki producing crushed stone (density 2.68 g / cm ³⁾ were added as coarse aggregate , Table 3 Formulation No. In No. 2, bentonite (manufactured by Wako Pure Chemical Industries, Ltd.) was further added and kneaded for 10 seconds. After that, a defoamer (trade name AFK-2 manufactured by Takemoto Oil & Fat Co., Ltd.) was applied to 100 parts by mass of the binder so that the target slump flow was 600 ± 30 mm and the air volume was within the range of 2% or less. The mixture was added in the range of 0.01 parts by mass, and the additive for the water-hard composition used in Test Category 4 was added together with kneading water and kneaded for 90 seconds. Additives and antifoaming agents were regarded as part of water.

The kneading and testing of the compounded materials were carried out in an environment where the material temperature was set to 20 ± 3 ° C., the room temperature was set to 20 ± 3 ° C., and the humidity was set to 60% or more. For the prepared concrete compositions of each example, the slump flow immediately after kneading, the amount of air immediately after kneading, the separation resistance immediately after kneading, and the bleeding were determined as follows. Formulation No. Table 4 shows the results of No. 1 in Formulation No. The results of 2 are shown in Table 5.

-Slump flow: The concrete composition immediately after kneading was measured 3 minutes after the slump cone was pulled up in accordance with JIS-A1150.
-Amount of air: The concrete composition immediately after kneading was measured in accordance with JIS-A1128.
-Separation resistance: For the concrete composition immediately after kneading, the following criteria were visually observed 3 minutes after the slump cone was pulled up.
(Criteria for separation resistance)
A: Very good (no separation of aggregate and mortar paste)
B: Good (aggregate and mortar paste are slightly separated)
C: Bad (aggregate and mortar paste are separated)
D: Very bad (significant separation of aggregate and mortar paste)
-Bleeding: Measured according to JIS-A1123.
(Criteria for bleeding)
A: Very good (bleeding rate 0.00-4.00%)
B: Good (bleeding rate is 4.01 to 6.00%)
C: Bad (bleeding rate is over 6.00%)

In Table 4,
* 1: The total mass (solid content) of the components (A) and (B) with respect to 100 parts by mass of the binder.
* 2: By mass (solid content) of only component (C) with respect to 100 parts by mass of binder

In Table 5,
* 1: The total mass (solid content) of the components (A) and (B) with respect to 100 parts by mass of the binder.
* 2: By mass (solid content) of only component (C) with respect to 100 parts by mass of binder

(result)
As shown in Table 2, Examples 1 to 10 containing the A component and the B component have excellent compatibility as compared with Comparative Examples 7 and 8 which do not contain the A component and contain hydroxypropylmethyl cellulose instead of the B component. Was shown to be. Further, as shown in Table 4, Examples 11 to 20 containing the A component and the B component contain only the A component and the comparative examples 11 to 15 having only the B component without the A component. It was shown that the bleeding amount was small as well as showing sufficient separation resistance as compared with Comparative Example 16 containing the mixture. Further, as shown in Table 5, the A component and the B component are compared with Comparative Examples 21 to 25 containing only the B component without containing the A component and Comparative Example 26 containing only the A component without containing the B component. Examples 21 to 30 containing the components showed sufficient separation resistance and a small amount of bleeding. In addition, Comparative Examples 17, 18, 27, and 28, which did not contain the A component and contained hydroxypropylmethyl cellulose instead of the B component, were inferior in compatibility.

The additive for a hydraulic composition of the present invention can be used as an additive when preparing a hydraulic composition.

Claims (7)

An additive for a hydraulic composition containing the following component A and the following component B.
Component A has a structural unit formed from acrylic acid and / or salt thereof, the weight-average molecular weight _{M A} is less than 1000 to 100,000 polymer;
Component B has an acrylic acid and / or structural units from the salt, the weight-average molecular weight _{M B} is 100000 50000000 less polymer; The additive for a hydraulic composition according to claim 1, wherein the mass ratio A: B of the component A to the component B is 1:99 to 99: 1. The additive for a hydraulic composition according to claim 1 or 2, further comprising a carboxylic acid-based copolymer as a C component. The additive for a hydraulic composition according to claim 3, wherein the total mass% of the A component and the B component is 0.1 to 25% with respect to the mass of the C component. A hydraulic composition containing the additive for a hydraulic composition according to any one of claims 1 to 4. The hydraulic composition according to claim 5, further comprising a binder. The additive for a hydraulic composition according to claim 6, wherein the total mass part of the component A and the component B is 0.00005 to 0.04 parts by mass with respect to 100 parts by mass of the binder.