JP2017206427A - Multifunctional additive for concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-liquid type multifunctional additive capable of sufficiently solving following 5 problems at same time, 1) fluidity retention property, 2) material separation and generation bleeding water by precipitation of an aggregate, 3) strength enhancement of initial strength and material age 28 days, 4) crack by dry shrinkage and 5) freeze-thaw resistance when concrete relatively less in unit cement amount is prepared.SOLUTION: There is provided a one-liquid type multifunctional additive containing a specific water soluble vinyl copolymer as an A component, sodium silicate or a mixture of sodium silicate and calcium silicate as a B component, a specific sodium phosphate as a C component and specific polyalkylene glycol monoalkyl ether as a D component with the A component of 1 to 35%, the B component of 10 to 55%, the C component of 0.1 to 6% and the D component of 4 to 89.9% (total 100%) by mass% and used 0.4 to 5 pts.mass per 100 pts.wt. of a binder.SELECTED DRAWING: None

Description

  The present invention relates to a multifunctional admixture for concrete, and more specifically, imparts fluidity to concrete to suppress the generation of excessive bleeding water, and at the same time, exhibits sufficient early strength in the obtained concrete cured product, and further shrinks by drying. The present invention relates to a one-component type multi-functional admixture for concrete which is useful for reducing cracks due to corrosion and improving freeze-thaw resistance.

  Conventionally, in repair / reinforcement concrete work and on-site concrete work, in order to shorten the work period and save labor during construction by expressing sufficient early strength in the obtained concrete hardened material, as a binder in each application, Special cements such as hard cement, alumina cement, and ultra-high-strength Portland cement, and early-strength concrete using admixtures such as quick setting materials and hardening accelerators are used. Moreover, not only the improvement of early strength expression of hardened concrete but also the proposal of hardening acceleration technology for imparting a plurality of functions such as reducing cracks due to drying shrinkage has been made (see, for example, Patent Documents 1 to 6). ). However, when preparing concrete with a relatively small amount of unit binder, when using general-purpose Portland cement or mixed cement, the amount of bleeding water after preparation is large, and at the same time the early strength of the hardened concrete obtained There are many problems such as low expression and many cracks due to drying shrinkage in medium and long-term ages, and insufficient freeze-thaw resistance, and a one-component multi-functional admixture for concrete that solves these problems at the same time. desired.

  Japanese Patent Laid-Open No. 9-2855   JP 2007-254987 A   JP 2008-239416 A   JP-A-2015-124136   JP2015-147701A   JP2015-120630A

  The problem to be solved by the present invention is to provide a one-component multi-functional admixture for concrete that can simultaneously and sufficiently solve the above five problems. That is, in the case of preparing a concrete blend with a relatively small amount of unit cement as a binder, 1) poor flow retention over time to ensure pot life after preparation 2) settling of aggregate 3) Easily segregates material and generates a large amount of bleeding water. 3) Small initial strength at the age of one day and small strength enhancement at middle age. 4) Many cracks due to drying shrinkage. 5) Resistance to freezing and thawing. The present invention provides a multifunctional admixture for concrete that can solve the above five problems simultaneously and sufficiently.

  As a result of earnest research to solve the above-mentioned problems, the present inventors are a multi-functional admixture for concrete containing specific four components in a specific ratio, and are used in a specific ratio with respect to the binder. We have found that the multifunctional admixture for concrete is right and suitable.

  That is, the present invention comprises the following 4 components of the following A component, the following B component, the following C component and the following D component, and the A component is 1 to 35% by mass, the B component is 10 to 55% by mass, C It contains 0.1 to 6% by mass of components and 4 to 89.9% by mass (total 100% by mass) of component D, and a ratio of 0.4 to 5 parts by mass per 100 parts by mass of the binder The present invention relates to a multifunctional admixture for concrete characterized in that it is used in the above.

Component A: Polycarboxylic acid (salt) water-soluble vinyl copolymer

Component B: One or more selected from sodium silicate or a mixture of sodium silicate and calcium silicate.

Component C: One or two selected from disodium phosphate and monosodium phosphate.

Component D: an aliphatic polyether represented by the following chemical formula 1.

In chemical formula 1,
R ¹ : Aliphatic hydrocarbon group having 3 to 6 carbon atoms A ¹ : All polyalkylene glycols having a polyoxyalkylene group composed of 2 to 8 oxyethylene units and oxypropylene units in the molecule Residues excluding hydroxyl groups.

  The multifunctional admixture for concrete according to the present invention (hereinafter referred to as the admixture of the present invention) is a mixture composed of four components of an A component, a B component, a C component, and a D component. The component A is mainly composed of a water-soluble vinyl copolymer (hereinafter referred to as a vinyl copolymer) that plays a role as a dispersant. As the vinyl copolymer that can be used in the present invention, two types of vinyl copolymer X and vinyl copolymer Y can be used. As one of the two types, a vinyl copolymer having a mass average molecular weight of 2000 to 80000 having a constitutional unit E of 45 to 55 mol% and a constitutional unit F of 55 to 45 mol% (100 mol% in total) in the molecule. Compound X is mentioned. In the present invention, the mass average molecular weight of the vinyl copolymer of the component A is a polyethylene glycol equivalent mass average molecular weight measured by GPC method (gel permeation chromatography method, hereinafter the same).

  The structural unit E is one or more selected from a structural unit formed from maleic acid and a structural unit formed from maleic acid sodium salt. Specifically, 1) a structural unit formed from maleic acid, 2) a structural unit formed from maleic acid sodium salt, 3) a structural unit formed from maleic acid and a structural unit formed from sodium maleate Both are mentioned.

  The structural unit F is formed from α-allyl-ω-methyl-polyoxyethylene having a polyoxyethylene group composed of 10 to 80 oxyethylene units, preferably 15 to 60 oxyethylene units in the molecule. And one or two selected from structural units formed from α-allyl-ω-hydroxy-polyoxyethylene having a polyoxyethylene group composed of 10 to 80 oxyethylene units in the molecule More than one.

  The maleic acid (salt) -based vinyl copolymer X itself described as one type of the above component A is known and can be synthesized by a known method. For example, it can be synthesized using the methods described in Japanese Patent Registration No. 2541218, Japanese Patent Application Laid-Open No. 2005-132955, etc., but from the viewpoint that the high performance intended by the present invention is particularly easily obtained, It is preferable to use the synthesis method disclosed in the latter publication. That is, in the polymerization method of maleic anhydride and allyl ethers, those obtained by alkaline hydrolysis of a copolymer obtained by polymerization in a bulk state without using a polymerization solvent are preferable. Or a completely neutralized product. The vinyl copolymer has a mass average molecular weight of 2000 to 80000, preferably 3000 to 60000.

  Another one of the two types of vinyl copolymers is that 35 to 85 mol% of the structural unit G, 15 to 65 mol% of the structural unit H, and 0 to 5 mol% of the structural unit I in the molecule (total of 100 mol%). ) Having a mass average molecular weight of 5,000 to 100,000 (the GPC method). Preferably, those having a mass average molecular weight of 10,000 to 600,000 having 37 to 80 mol% of structural unit G, 20 to 60 mol% of structural unit H, and 0 to 3 mol% (100 mol% in total) of structural unit I preferable.

  The structural unit G is one or more selected from a structural unit formed from methacrylic acid and a structural unit formed from sodium methacrylate. Specifically, 1) a structural unit formed from methacrylic acid, 2) a structural unit formed from sodium methacrylate, 3) a structural unit formed from methacrylic acid and a structural unit formed from sodium methacrylate. Both are mentioned.

  The structural unit H is a structural unit formed from methoxypolyethylene glycol having a polyoxyethylene group composed of 7 to 90 oxyethylene units, preferably 15 to 80 oxyethylene units in the molecule.

  The structural unit I is a structural unit composed of (meth) allylsulfonic acid sodium salt. Specific examples include sodium allyl sulfonate and sodium methallyl sulfonate, with sodium methallyl sulfonate being preferred.

  The methacrylic acid (salt) -based vinyl copolymer Y itself described as one type of the above component A can be synthesized by a known method. For this purpose, for example, synthesis can be carried out using the methods described in JP-A-58-74552 and JP-A-1-226757.

  In the present invention, as the component A described above, any vinyl copolymer selected from vinyl copolymer X and vinyl copolymer Y can be used, but vinyl copolymer X having no ester bond is preferred. That is, when commercializing as a one-component aqueous solution of a multifunctional admixture, it is important that hydrolysis does not occur easily in an alkaline solution during storage. From the viewpoint that the one-component product is stable over time, Vinyl copolymer X is preferred over copolymer Y.

Component B is one or more selected from sodium silicate alone or a mixture of sodium silicate and calcium silicate. In the present invention, the role of the component B is used as a role of promptly stopping the fluidity after the filling work while ensuring the fluid retention time of the concrete for a certain period of time to accelerate the setting and accelerate the curing reaction. In the case of sodium silicate alone, it is preferable to use water glass containing sodium silicate as a main component from the viewpoint of industrial availability. The molecular formula of water glass is represented by Na ₂ O · nSiO ₂ and is not limited, but is a compound from No. 1 to No. 3 defined in JIS-K1408, in other words, silicon dioxide with respect to sodium oxide represented by the molecular formula The molar ratio (n) in the range of SiO ₂ / Na ₂ O = 1.8 to 3.5 can be advantageously used. Among these ranges, those having a high molar ratio are preferably used.

  When used in a mixture of sodium silicate and calcium silicate, the composition ratio of the mixture is 85 to 99.95% by mass of sodium silicate and 0.05 to 15% by mass of calcium silicate (100 in total). Silicate mixture containing sodium silicate in a proportion of 90-99.9% by mass and calcium silicate in a proportion of 0.1-10% by mass (total 100% by mass). . In the present invention, when calcium silicate is used, water of crystallization is usually contained, but when prepared as an aqueous solution or suspension, it is converted as a mass ratio excluding water of crystallization.

  Component C is one or two selected from disodium phosphate and monosodium phosphate. Of these, disodium phosphate is preferred from the viewpoint of good solubility in water. In the present invention, the role of the component C is to delay the rapid setting action of the component B causing a rapid hydration reaction of the cement for a certain period of time, and to secure the desired fluid retention time while reducing the setting time and early setting time of the cement. Used for adjustment purposes.

  The component D is a polyalkylene glycol monoalkyl ether represented by the following chemical formula 1.

However, in chemical formula 1,
R ¹ : Alkyl group having 3 to 6 carbon atoms A ¹ : Excluding all hydroxyl groups from polyalkylene glycol having a polyoxyalkylene group composed of a total of 2 to 10 oxyethylene units and oxypropylene units in the molecule Those that are compatible with the conditions of the compound consisting of the remaining residues can be used in the present invention.

As the compound of Chemical Formula 1 in the D component, preferably, R ¹ is a butyl group having 4 carbon atoms, and A ¹ is a polyoxyethylene unit composed of a total of 3 to 8 oxyethylene units and oxypropylene units in the molecule. The compound which consists of the residue remove | excluding all the hydroxyl groups from the polyalkylene glycol which has an oxyalkylene group is mentioned, The component D itself can use a liquid thing advantageously at normal temperature, and it can synthesize | combine by a well-known method. Further, in the present invention, the role of the component D is that each component is uniform and chemically stable without generating precipitates when the admixture of the present invention comprising a plurality of components is dissolved or dispersed in water. Is used to obtain a one-component type admixture for concrete, and at the same time, it is used as a function imparting a function of suppressing shrinkage cracking of the hardened concrete after hardening.

  The admixture of the present invention is composed of the four components of the A component, B component, C component and D component described above, the A component is 1 to 35% by mass, the B component is 10 to 55% by mass, and the C component is 0. 0.1 to 6% by mass and D component in a ratio of 4 to 89.9% by mass (total 100% by mass), preferably 5 to 30% by mass of A component and 15 of B component It is a one-component admixture containing ˜50 mass%, C component of 0.3-5 mass%, and D component of 15-79.7 mass% (total 100 mass%). If the ratio of A component, B component, C component and D component is out of the range, slump loss will occur within a certain required work time (for example, after 30 minutes of mixing) when preparing concrete. When it becomes large and workability deteriorates, and when compacted concrete is filled into the mold, vibration compaction is likely to cause material separation due to the settling of aggregates, resulting in a large amount of bleeding water. In the obtained cured product, the effect of improving the initial age strength is small, or in the durability of the cured product in the medium to long-term age, the drying shrinkage is large and the occurrence of cracking is further insufficient. It is difficult to simultaneously solve a plurality of problems targeted by the present invention in a balanced manner.

  The admixture of the present invention is used at a rate of 0.4 to 5 parts by mass per 100 parts by mass of the binder, but preferably 0.5 to 3 parts by mass. If the amount of the admixture of the present invention is out of this range, the effects of the present invention as described above cannot be obtained.

  The type of concrete binder using the admixture of the present invention is not particularly limited, and includes ordinary Portland cement, early-strength Portland cement, ultra-early strong Portland cement, moderately hot Portland cement, low heat Portland cement, and the like. Examples include various Portland cements, and also include mixed cements such as blast furnace cement containing blast furnace slag fine powder, fly ash cement containing fly ash fine powder, and silica fume cement containing silica fume fine powder. be able to. In the present invention, in the case of concrete prepared with a water binder ratio of 35 to 65%, it is preferable to use portland cement such as ordinary Portland cement and early-strength Portland cement which are easily available as a binder. When mixed cement is used, it is useful to apply it to concrete prepared with a water binder ratio of 35 to 65%, preferably 40 to 60%.

  When preparing concrete using the admixture of the present invention, kneaded water, fine aggregate and coarse aggregate are used in addition to the admixture and binder of the present invention. Tap water can be used as the mixing water, known river sand, mountain sand, crushed sand, etc. can be used as fine aggregate, and known river gravel, crushed stone, lightweight aggregate, etc. can be used as coarse aggregate. .

The admixture of the present invention has a water binder ratio of 35-65%, preferably 40-60% concrete, and a binder unit amount of 280-500 kg / m ³ , preferably 300-450 kg / m ³ . Especially useful for concrete. While maintaining the fluidity retention of the prepared concrete over time for a certain period of time, it suppresses material separation and suppresses the generation of bleeding water. Can reduce drying shrinkage and increase freeze-thaw resistance.

  Further, when preparing concrete using the admixture of the present invention, other than AE (air entrainment) agent, antifoaming agent, waterproofing agent, antiseptic agent, rust inhibitor, etc., within the range not impairing the effects of the present invention. These admixtures can be used in combination.

  The desired concrete can be prepared by kneading the admixture, binder, water, fine aggregate, coarse aggregate and the like of the present invention described above by a known method. Specifically, Portland cement as a binder, a part of water, fine aggregate and coarse aggregate are kneaded with a mixer, while the admixture of the present invention and an AE regulator as necessary are mixed with water. The desired concrete can be prepared by diluting the remainder and then kneading both. When preparing the concrete, the admixture of the present invention is prepared in advance as a one-part aqueous solution or water-dispersed suspension having a solid concentration (total concentration of component A, component B, component C and component D) of 10 to 50% by mass. It is preferable to adjust to a state from the viewpoint of easy handling and uniformity of kneading, and in particular, from the viewpoint of efficient storage and measurement of the admixture in a ready-mixed concrete plant.

  In the admixture of the present invention described above, in preparation of early-strength concrete with a relatively small amount of unit cement, 1) the fluidity retention over time for ensuring workability after kneading is not good. 3) Material separation due to sedimentation of aggregate is likely to occur, and generation amount of bleeding water is large. 3) Initial strength of material day is small and strength enhancement of medium age material is small. 4) Cracking due to drying shrinkage is large. ) Provided is a multi-functional admixture for concrete capable of simultaneously and sufficiently solving the above five problems, which have insufficient freeze-thaw resistance.

  Hereinafter, in order to make the configuration and effects of the present invention more specific, examples and the like will be described. However, the present invention is not limited to the examples. In the following examples and the like, unless otherwise indicated,% means mass%, and part means mass part.

Test Category 1 (Synthesis of component A water-soluble vinyl copolymer)
-Synthesis of (xa-1) as water-soluble vinyl copolymer X 98 g of maleic anhydride and 512 g of α-allyl-ω-methyl-poly (n = 33) oxyethylene were charged into a reaction vessel and gradually heated. Then, the mixture was uniformly dissolved with stirring, and the atmosphere in the reaction vessel was replaced with nitrogen. The temperature of the reaction system was maintained at 83 ° C. in warm water, and 2 g of benzoyl peroxide was added to initiate radical polymerization reaction. Further, 3 g of benzoyl peroxide was added in portions, and the radical polymerization reaction was continued for 4 hours. The obtained copolymer was hydrolyzed by adding water to obtain a 40% aqueous solution of the water-soluble vinyl copolymer (xa-1). When the water-soluble vinyl copolymer (b-1) was analyzed, structural unit formed from maleic acid / structural unit formed from α-allyl-ω-methyl-polyoxyethylene (n = 33) = 50 / It was a water-soluble vinyl copolymer having a mass average molecular weight of 42,000 (GPC method, converted to pullulan) at a ratio of 50 (molar ratio).

Synthesis of (xa-3) as water-soluble vinyl copolymer X α-allyl-ω-hydroxy-poly (n = 30) oxyethylene 1370 g (1.0 mol), maleic acid 116 g (1.0 mol) And 1760 g of water were charged in a reaction vessel and dissolved uniformly with stirring, and then the atmosphere was replaced with nitrogen. The temperature of the reaction system was kept at 70 ° C. in a warm water bath, and 8 g of a 20% aqueous solution of sodium persulfate was added to initiate radical polymerization reaction. Further, 5 g of a 20% aqueous solution of sodium persulfate was added and the radical polymerization reaction was continued for 5 hours to complete the reaction to obtain a water-soluble vinyl copolymer. Then, 167 g (2.0 mol) of a 48% aqueous sodium hydroxide solution was obtained. ) Was added to neutralize, and 390 g of water was added to obtain a 40% aqueous solution of the water-soluble vinyl copolymer (xa-3). When the water-soluble vinyl copolymer (xa-3) was analyzed, structural unit formed from sodium maleate / structural unit formed from α-allyl-ω-methyl-polyoxyethylene (n = 30) = 50. It was a water-soluble vinyl copolymer having a mass average molecular weight of 51600 (GPC method, converted to pullulan) at a ratio of / 50 (molar ratio).

Synthesis of water-soluble vinyl copolymer (xa-2), (xar-1), (xar-2), (xar-4) and (xar-5) Vinyl copolymers (xa-2), (xar-1), (xar-2), (xar-4) and (xar-5) were synthesized.

Synthesis of water-soluble vinyl copolymers (xar-3) and (xar-6) Water-soluble vinyl copolymers (xar-3) and (xar-6) were synthesized by the same synthesis method as (xa-3). did. The contents of the water-soluble vinyl copolymer B synthesized above are summarized in Table 1.

In Table 1,
* 1: GPC method, pullulan conversion L-1: maleic acid L-2: sodium maleate M-1: α-allyl-ω-methyl-poly (n = 33) oxyethylene M-2: α-allyl-ω -Methyl-poly (n = 68) oxyethylene M-3: α-allyl-ω-hydroxy-poly (n = 30) oxyethylene M-4: α-allyl-ω-methyl-poly (n = 90) oxy Ethylene M-5: α-allyl-ω-methyl-poly (n = 8) oxyethylene M-6: α-allyl-ω-hydroxy-poly (n = 8) oxyethylene

Synthesis of (ya-1) as water-soluble vinyl copolymer Y: 60 g of methacrylic acid, methoxypoly (23 oxyethylene units, hereinafter n = 23) 300 g of ethylene glycol methacrylate and 5 g of sodium methallylsulfonate, 3-mercapto After charging 3 g of propionic acid and 490 g of water into the reaction vessel, 58 g of 48% aqueous sodium hydroxide solution was added, and the mixture was partially neutralized with stirring and dissolved uniformly. After the atmosphere in the reaction vessel was replaced with nitrogen, the temperature of the reaction system was maintained at 60 ° C. in a warm water bath, 25 g of a 20% aqueous solution of sodium persulfate was added to start radical polymerization reaction, and the reaction was continued for 5 hours. The reaction was terminated. Thereafter, 23 g of a 48% aqueous sodium hydroxide solution was added to completely neutralize the reaction product, thereby obtaining a 40% aqueous solution of a water-soluble vinyl copolymer (ya-1). When the water-soluble vinyl copolymer (ya-1) was analyzed, it was formed from a structural unit formed from sodium methacrylate / a structural unit formed from methoxypoly (n = 23) ethylene glycol methacrylate / sodium methallylsulfonate. The structural unit was a water-soluble vinyl copolymer having a mass average molecular weight of 35500 (GPC method, converted to pullulan) at a ratio of 70/27/3 (mol%).

Synthesis of water-soluble vinyl copolymers (ya-2) to (ya-3) and (yar-1) to (yar-3) In the same manner as (ya-1), the water-soluble vinyl copolymer (ya -2) to (ya-3) and (yar-1) to (yar-3) were synthesized. The contents of the water-soluble vinyl copolymer Y synthesized above are summarized in Table 2.

In Table 2,
* 1: GPC method, pullulan conversion g-1: sodium methacrylate g-2: methacrylic acid h-1: methoxypoly (23 mol) ethylene glycol methacrylate h-2: methoxypoly (70 mol) ethylene glycol methacrylate i-1: meta Sodium rylsulfonate i-2: Sodium allylsulfonate i-3: Methyl acrylate

Test Category 2 (Preparation and evaluation of multifunctional admixture)
Example 1 {Preparation of Multifunctional Admixture (P-1)}
500 parts of 40% aqueous solution of (xa-1) of water-soluble vinyl copolymer X as A component, sodium silicate as B component (trade name: Showa Chemical Co., Ltd., water glass No. 3, molar ratio SiO ₂ / Na 625 parts of 40% aqueous solution (b-1) of ₂ O = 3 to 3.3), 20 parts of disodium phosphate (c-1) as C component, and poly (n = 2 mol) ethylene glycol as D component 530 parts of poly (n = 2 mol) propylene glycol monobutyl ether (d-1) and 825 parts of tap water are mixed and dissolved uniformly. A component / B component / C component / D component = 20/25/2 A multifunctional admixture (P-1) having an aqueous solution concentration of 40% by mass comprising / 53 (mass ratio, total 100%) components was prepared.

Examples 2 and 3
In the same manner as in the preparation of Example 1, multifunctional admixtures (P-2) and (P-3) having an aqueous solution concentration of 40% by mass were prepared.

Example 4
625 parts of a 40% aqueous solution of a water-soluble vinyl copolymer (xa-1) as component A, sodium silicate (trade name: water glass No. 1 manufactured by Showa Chemical Co., Ltd., molar ratio SiO ₂ / Na ₂ O, as component B) = 2 to 2.3) 40% aqueous solution (b-2), 750 parts, C component as monosodium phosphate (c-2), 30 parts, D component as poly (n = 2 mol) ethylene glycol poly ( n = 2 mol) 420 parts of propylene glycol monobutyl ether (d-1) and 675 parts of tap water are mixed and dissolved uniformly. A component / B component / C component / D component = 25/30/3/42 A multifunctional admixture (P-4) having an aqueous solution concentration of 40% by mass composed of components (mass ratio, total 100%) was prepared.

Example 5
375 parts of 40% aqueous solution of water-soluble vinyl copolymer (xa-1) as component A, sodium silicate (powder reagent product) / calcium silicate (powder reagent product) = 96/4 (mass ratio, 200 parts of a total (100) mixture (b-3), 20 parts of disodium phosphate (c-1) as C component, and poly (n = 3 mol) ethylene glycol poly (n = 3 mol) propylene as D component 630 parts of glycol monobutyl ether (d-2) and 1275 parts of tap water are mixed and dissolved, and A component / B component / C component / D component = 25/30/3/42 (mass ratio, total 100%) A multifunctional admixture (P-5) having an aqueous solution concentration of 40% by mass was prepared.

Examples 6-8
The multifunctional admixtures (P-6) to (P-8) having an aqueous solution concentration of 40% by mass were prepared in the same manner as in the preparation of Examples 1 to 3, except that the water-soluble vinyl copolymer Y was used as the component A. Prepared.

Example 9
A multifunctional admixture (P-9) having an aqueous solution concentration of 40% by mass was prepared in the same manner as in Example 4 except that the water-soluble vinyl copolymer Y was used as the component A.

Example 10
A multifunctional admixture (P-10) having an aqueous solution concentration of 40% by mass was prepared in the same manner as in Example 5 except that the water-soluble vinyl copolymer Y was used as the component A.

Comparative Examples 1 to 18 {Preparation of Multifunctional Admixtures (R-1) to (R-18)}
In the same manner as in the preparation of the multifunctional admixture (P-1) of Example 1, multifunctional admixtures (R-1) to (R-18) having an aqueous solution concentration of 40% by mass were prepared.
The contents of each multifunctional admixture prepared above are summarized in Table 3.

Evaluation of stability of aqueous solution of multifunctional admixture 40% aqueous solutions of prepared multifunctional admixtures (P-1) to (P-10) and (R-1) to (R-18) The sample was placed in a graduated cylinder and allowed to stand at room temperature for 1 week, then visually judged and evaluated according to the following criteria. The results are summarized in Table 3.
Evaluation criteria (circle): It is transparent and uniform, or it is slightly turbid, but it is uniform without isolate | separating.
X: Clearly separated.

In Table 3,
xa-1 to xa-3, xar-1 to xar-6: water-soluble vinyl copolymers of Table 1 synthesized in Test Category 1 ya-1 to ya-3, yar-1 to yar-3: Test Category 1 Water-soluble vinyl copolymer b-1 of Table 2 synthesized in Step 1: Sodium silicate (Product name: Showa Chemical Co., Ltd .: Water glass No. 3, molar ratio SiO ₂ / Na ₂ O = 3 to 3.3)
b-2: Sodium silicate (Product name: Showa Chemical Co., Ltd .: Water glass No. 1, molar ratio SiO ₂ / Na ₂ O = _{2 to} 2.3)
b-3: Sodium silicate / calcium silicate = 96/4 (mass ratio, total 100) mixture c-1: disodium phosphate c-2: monosodium phosphate cr-1: trisodium phosphate d -1: poly (n = 2 mol) ethylene glycol poly (n = 2 mol) propylene glycol monobutyl ether d-2: poly (n = 3 mol) ethylene glycol poly (n = 3 mol) propylene glycol monobutyl ether dr-1 : Poly (n = 6 mol) ethylene glycol monobutyl ether

Test category 3 (Preparation and evaluation of concrete)
Test Examples 1-10
Using a multifunctional admixture described in Table 3 prepared in Test Category 2, a binder (ordinary Portland cement (density = 3) was added to a 50-liter pan-type forced kneader mixer under the conditions of Formulation No. 1 described in Table 4. .16 g / cm ³ ), fine aggregate (river sand, density = 2.58 g / cm ³ ), kneaded water (tap water), multifunctional admixture (P-1) and air amount regulator (manufactured by Takemoto Yushi Co., Ltd.) AE agent, trade name AE300) were sequentially added and kneaded until the slurry was uniform, and the amount of multifunctional admixture used is shown in Table 5. Next, coarse aggregate (crushed stone, density) = 2.68 g / cm ³ ) and kneaded for 30 seconds to prepare the concrete of Example 1 with a target slump of 18 ± 1 cm and a target air amount of 4 ± 1%. 2 to 10 concretes were prepared and in each case kneaded The mixing temperature was 20 ° C.

Test Examples 11-20
In the same manner as in Test Examples 1 to 10, the concretes of Test Examples 11 to 20 were prepared under the conditions of blending number 2 described in Table 4. The kneading temperature was 20 ° C. in all cases. Table 5 summarizes the test results of the concrete after mixing, and Table 6 summarizes the test results of the cured body.

Test Examples 31-56
Using the multifunctional admixture of Comparative Example described in Table 3 prepared in Test Category 2, the target slump is 18 ± 1 cm and the target air amount is 4 ± 1% under the conditions of Formulation No. 1 described in Table 4. Concretes of Comparative Examples 21 to 38 were prepared. Further, concretes of Comparative Examples 39 to 56 having a target slump of 18 ± 1 cm and a target air amount of 4 ± 1% under the conditions of the blending number 2 shown in Table 4 were prepared. The kneading temperature was 20 ° C. in all cases. Table 7 shows the test results of the concrete after mixing, and Table 8 shows the test results of the cured body.

In Table 2,
* 1: Ordinary Portland cement (density = 3.16 / cm ³ )
* 2: Blast furnace cement type B (density = 3.04 g / cm ³ )
* 3: Fine aggregate (river sand, density = 2.58 g / cm ³ )
* 4: Coarse aggregate (crushed stone, density = 2.68 g / cm ³ )

-Evaluation of physical properties of concrete Slump and air amount immediately after mixing, slump and air amount 30 minutes after mixing, bleeding rate, compressive strength, drying shrinkage rate, freeze-thaw durability index Obtained and evaluated as follows, and the results are summarized in Tables 5 to 8.

-Slump (cm): It measured based on JIS-A1101 about the concrete which left still on the kneading boat for 30 minutes after it kneaded.
-Slump residual ratio (%): slump value after standing for 30 minutes / slump value immediately after kneading) x 100.
-Air amount (volume%): It measured based on JIS-A1128 about the concrete left still in the kneading boat for 30 minutes after it kneaded.
-Bleeding rate: It measured based on JIS-A1123.
The smaller the value, the smaller the upper surface settlement and the more homogeneous.
-Compressive strength (N / mm < ² >): It measured based on JIS-A1108 about the hardening body of material age 1 day, material age 3 days, and material age 28 days.
-Drying shrinkage: In accordance with JIS-A1132, a test specimen was prepared by filling a steel rectangular mold with dimensions of 10 cm x 10 cm x 40 cm, and the material age was 26 weeks (182) by the comparator method according to JIS-A1129. The drying shrinkage rate was measured on the day.
-Freezing and thawing durability index (300 cycles): About the concrete of each example, the value calculated by the durability index of ASTM-C666-75 was shown using the value measured based on JIS-A1148. This numerical value indicates that the maximum value is 100, and the closer to 100, the better the resistance to freezing and thawing.

In Tables 5 to 8,
Formulation number: Formulation number described in Table 4 * 1: Type of multifunctional admixture described in Table 3 * 2: Addition mass part of multifunctional admixture (as solid content) to 100 parts by mass of cement * 3: Multifunction Since the aqueous solution of the admixture was completely precipitated or phase-separated, it was not used and was not measured.
* 4: Measurement was not performed because the desired fluid concrete could not be obtained.

  As is clear from the results of Tables 5 to 8, according to the admixture of the present invention, when used for the preparation of a blend having a relatively small unit cement amount, the fluidity drop over time after kneading is reduced. The amount of air and the amount of air can be suppressed, the working time can be secured, the amount of bleeding water of the prepared concrete can be reduced, and the compressive strength of the initial ages (ages 1 and 3) is increased. Furthermore, drying shrinkage of the cured body is suppressed, shrinkage cracks are few, and at the same time, resistance to freezing and thawing is excellent, and high-quality early strength concrete can be prepared.

Claims (9)

It consists of 4 components of the following A component, the following B component, the following C component, and the following D component, and A component is 1-35 mass%, B component is 10-55 mass%, C component is 0.1 -6 mass% and D component are contained in the ratio of 4-89.9 mass% (total 100 mass%), and it should be used at a ratio of 0.4-5 mass parts per 100 mass parts of the binder. A multifunctional admixture for concrete, characterized by comprising:
Component A: One or two or more water-soluble vinyl copolymers selected from the following water-soluble vinyl copolymer X and the following water-soluble vinyl copolymer Y Water-soluble vinyl copolymer X: A water-soluble vinyl copolymer having a mass average molecular weight of 2000 to 80000 having a structural unit E of 45 to 55 mol% and a structural unit F of 55 to 45 mol% (100 mol% in total).
Structural unit E: One or two selected from a structural unit formed from maleic acid and a structural unit formed from maleic acid sodium salt.
Structural unit F: Structural unit formed from α-allyl-ω-methyl-polyoxyethylene having a polyoxyethylene group composed of 10 to 80 oxyethylene units in the molecule and 10 to 80 in the molecule One or two or more selected from structural units formed from α-allyl-ω-hydroxy-polyoxyethylene having a polyoxyethylene group composed of oxyethylene units.
Water-soluble vinyl copolymer Y: 35 to 85 mol% of the following structural unit G in the molecule, 15 to 65 mol% of the following structural unit H and 0 to 5 mol% of the following structural unit 1 (100 mol in total) %) A water-soluble vinyl copolymer having a mass average molecular weight of 2000 to 100,000.
Structural unit G: One or two selected from a structural unit formed from methacrylic acid and a structural unit formed from sodium methacrylate.
Structural unit H: a structural unit formed from methoxypolyethylene glycol having a polyoxyethylene group composed of 7 to 90 oxyethylene units in the molecule.
Structural unit I: a structural unit composed of (meth) allylsulfonic acid sodium salt.
Component B: One or more selected from sodium silicate or a mixture of sodium silicate and calcium silicate.
Component C: One or two selected from disodium phosphate and monosodium phosphate.
Component D: polyalkylene glycol monoalkyl ether represented by the following chemical formula 1

(In chemical formula 1,
R ¹ : Alkyl group having 3 to 6 carbon atoms A ¹ : Excluding all hydroxyl groups from polyalkylene glycol having a polyoxyalkylene group composed of a total of 2 to 10 oxyethylene units and oxypropylene units in the molecule Residue. )   The multifunctional admixture for concrete according to claim 1, wherein the component A is a water-soluble vinyl copolymer X and has a mass average molecular weight of 3000 to 50000. The multifunctional admixture for concrete according to claim 1 or 2, wherein the B component is sodium silicate, and the molar ratio of SiO ₂ / Na ₂ O represented by the molecular formula of the compound is 1.8 to 3.5.   B component is a mixture of sodium silicate and calcium silicate, and the composition ratio of the mixture is 90 to 99.9% by mass of sodium silicate, 0.1 to 10% by mass of calcium silicate (total 100% by mass) The multifunctional admixture for concrete according to claim 1 or 2, which is a silicate mixture contained in a ratio of   The multifunctional admixture for concrete according to any one of claims 1 to 4, wherein the component C is disodium phosphate.   The component D is a polyether of an aliphatic hydrocarbon group having 4 carbon atoms and is composed of a total of 3 to 8 oxyethylene units and oxypropylene units in the molecule, the oxyethylene units and the oxypropylene units The multi-functional admixture for concrete according to any one of claims 1 to 5, wherein and are polyalkylene glycol monoalkyl ethers added in block form.   A component is 5-30 mass%, B component is 15-50 mass%, C component is 0.3-5 mass%, and D component is contained in the ratio of 15-79.7 mass% (total 100 mass%). The multifunctional admixture for concrete according to any one of claims 1 to 6.   The multifunctional admixture for concrete according to any one of claims 1 to 7, which is for concrete which uses Portland cement as a binder and the water binder ratio is adjusted to 35 to 65%.   The multifunctional admixture for concrete according to any one of claims 1 to 7, which is for concrete using a mixed cement as a binder and adjusting the water binder ratio to 35 to 65%.