JPH0532338B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a hydraulic cement composition. Hydraulic cement compositions represented by cement paste, cement mortar, concrete, etc. include lignin sulfonate, hydroxycarboxylate, naphthalene sulfonate formalin condensate salt, polycyclic aromatic sulfonate, melamine sulfonate formalin. It is known to incorporate cement dispersants such as condensate salts and copolymer salts of α,β-unsaturated carboxylic acid and chain olefin. Among these, salts of formalin condensates of naphthalenesulfonic acid and salts of formalin condensates of melaminesulfonic acid are particularly widely used because of their excellent water-reducing performance. By the way, in hydraulic cement compositions, after the mixture is kneaded, hydration and aggregation of cement particles progress over time, resulting in a decrease in fluidity (hereinafter referred to as slump loss), resulting in a decrease in workability and workability. . In general, in the case of hydraulic cement compositions that do not contain cement dispersants, or in the case of hydraulic cement compositions that contain AE water reducers, foam entraining agents (AE agents), etc., the adverse effects of slump loss are comparatively low. However, in the case of hydraulic cement compositions containing highly water-reducing cement dispersants such as naphthalene sulfonate formalin condensate salts and melamine sulfonate formalin condensate salts, the slump The negative impact of loss is significant. Contains a cement dispersant with excellent water reduction performance,
In the case of a highly water-reduced hydraulic cement composition, the slump loss tends to be large, which reduces the workability and workability, and limits the pot life. For example, when manufacturing secondary concrete products, after kneading the mixture,
If slump loss occurs in the concrete over time for any reason, it will cause pump blockage when pumping the concrete, and if slump loss occurs in the concrete due to too much time filling the formwork, it will cause problems when forming the concrete. Generate unfilled areas. In the case of ready-mixed concrete, slump loss during transportation also causes pump blockage and reduces work efficiency. The present invention contains a cement dispersant with excellent water reduction performance, and even when water is reduced to a high degree, it has a high degree of fluidity and a small slump loss, thus improving ease of application and workability. The present invention relates to a hydraulic cement composition. <Prior art and its problems> Conventionally, as a means to prevent slump loss, there has been a method of incorporating retardant substances such as oxycarboxylic acid salts and lignin sulfonate (Japanese Patent Application Laid-open No. 17918-1983), and naphthalene sulfonic acid formalin condensate. Means of dividing or continuously blending a fluidizing agent such as salt
15856), means for blending fluidizing agents such as naphthalene sulfonic acid formalin condensate salts in powder or granule form (Japanese Patent Publication No. 54-139929), water-soluble salts of copolymers of olefins and ethylenically unsaturated dicarboxylic acids. A method of blending polycarboxylic acid-based water-soluble polymers such as polycarboxylic acid-based water-soluble polymers and other water-soluble polymers in combination with naphthalene sulfonic acid formalin condensate salt (Japanese Patent Application Laid-Open No. 1989-1999)
-16850, JP-A-60-161364, JP-A-61-183157,
JP-A No. 62-158151), Means for blending fine powder of copolymer of olefin and ethylenically unsaturated dicarboxylic anhydride (JP-A No. 61-26543, JP-A No. 63-
5346) etc. have been proposed. However, all of these conventional methods still have the problem of insufficient prevention of slump loss, and some methods are unsuitable for on-site work that requires simple and quick work, or are unsuitable for cement composition. There is a problem in that it has a negative effect on the original properties of things. <Problems to be Solved by the Invention and Means for Solving the Problems> The present invention provides a new hydraulic cement composition that solves the conventional problems as described above. Therefore, the present inventors have formulated a cement dispersant with excellent water reduction performance, which has high fluidity and small slump loss even when water is reduced to a high degree, and therefore has improved workability. As a result of intensive research to obtain a hydraulic cement composition with improved workability, we discovered that it is correct and suitable to mix a specified amount of a cement dispersant consisting of a specific two-component system with respect to the solid content of cement. The invention was completed. That is, the present invention relates to a hydraulic cement composition which essentially comprises blending 0.1 to 3.0 parts by weight of a cement dispersant consisting of the following components a and b to 100 parts by weight of cement solid content. Component a: alkali metal salt or alkaline earth metal salt of formalin condensate of aromatic sulfonic acid,
Or an alkali metal salt or alkaline earth metal salt of a formalin condensate of N-sulfomethylated melamine. Component b: It contains the following monomers A, B and C, and the copolymerization ratio of the monomers is A/B/C=57-5/3-25/85-40 (weight ratio )
A water-soluble vinyl copolymer. [However, R ¹ , R ² , R ³ are H or CH ₃ . R ⁴ is an alkyl group having 1 to 3 carbon atoms. X is −SO ₃ M ² or

[Formula] M ¹ and M ² are alkali metals, alkaline earth metals, ammonium, or organic amines. n is an integer from 5 to 50. ] In the present invention, known components can be used as component a. Among component a, the alkali metal salts or alkaline earth metal salts of formalin condensates of aromatic sulfonic acids include alkali metal salts or alkaline earth metal salts of formalin condensates of naphthalene sulfonic acids (for example, Japanese Patent Publication No. 41-11737 (as stated in the issue)
is preferred. For creosote oil, naphthalene oil, liquefied coal oil, etc., sulfonated compounds containing naphthalene rings contained in these oils can be co-condensed with formalin. Commercially available products include Mighty 150 (manufactured by Kao Corporation) and Paul Fine 510 (manufactured by Takemoto Yushi Co., Ltd.) can be advantageously used. Among component a, the alkali metal salt or alkaline earth metal of formalin condensate of N-sulfomethylated melamine is commonly known as melamine sulfonic acid formalin condensate salt, and is produced by the following method. It is something. That is, melamine is reacted with formaldehyde to form N-methylolated melamine, and further a bisulfite such as an alkali metal bisulfite salt or an ammonium salt is reacted to sulfomethylate a portion of the methylol groups. Next, a mineral acid such as sulfuric acid is added to make the reaction system acidic, and the methylol group and free amino group are dehydrated and condensed to form a formalin condensate. Then, the free sulfonic acid groups are neutralized by adding an alkali hydroxide or the like to obtain a salt of a formalin condensate of melamine sulfonic acid (for example, the method described in Japanese Patent Publication No. 37058/1983). As the alkali metal salt or alkaline earth metal salt of formalin condensate of N-sulfomethylated melamine, N-
It is preferable that the formalin condensate of sulfomethylated melamine has an average number of bonded sulfonic acid groups of 0.85 to 1.2 per triazine ring in terms of dispersibility and water solubility. ) and Pozolith NL-4000 (manufactured by Nisso Master Builders) can be used advantageously. In the present invention, component b is a monomer of A, B
and C are copolymerized in a specific ratio. Examples of the monomer A include alkali metal salts, alkaline earth metal salts, and alkanolamine salts of acrylic acid and methacrylic acid. Examples of the monomer B include alkali metal salts, alkaline earth metal salts, and alkanolamine salts of methallylsulfonic acid and P-methallyloxybenzenesulfonic acid. Furthermore, as the monomer of C, methoxypolyethylene glycol, ethoxypolyethylene glycol, propoxypolyethylene glycol,
An esterified product of monoalkoxypolyalkylene glycol such as isopropoxypolyethylene glycol, methoxypolyethylenepolypropylene glycol, ethoxypolyethylenepolypropylene glycol, and acrylic acid or methacrylic acid, the number of moles of polyalkylene glycol added is 5 to 50, and Examples include those soluble in water or hot water. In this case, in order to make the esterified product soluble in water or hot water, the ratio of the hydrophilic polyethylene glycol chain in the polyalkylene glycol chain and the number of added moles are appropriately selected within the above range. A constituting the water-soluble vinyl copolymer of component b,
The content ratio of each monomer of B and C is A/B/C=
It is 57-5/3-25/85 (weight ratio). If a vinyl copolymer in which the content ratio of each monomer A, B, and C is outside this range is used, the vinyl copolymer
When mixed with component A, precipitation separation occurs due to insufficient compatibility, and when the vinyl copolymer is mixed with component a and used as a dispersant for cement, sufficient slump loss prevention effect cannot be obtained. . Among the monomers A, B, and C constituting the water-soluble vinyl copolymer that is component b, monomer B is particularly important in terms of its performance. A vinyl copolymer composed of monomer A and monomer C has a sufficient slump loss prevention effect when mixed with component a and used as a cement dispersant. I can't. However, when a water-soluble vinyl copolymer composed of monomers A, monomers C, and monomer B is mixed with component a and used as a dispersant for cement, it has excellent properties. This is because the effect of preventing slump loss can be obtained. The water-soluble vinyl copolymer, which is component b, may be mixed with acrylamide, methacrylamide, or acrylonitrile for various purposes, such as improving compatibility with component a, within a range that does not impair its original effect. It may also contain 10% by weight or less of other monomer components such as acrylic acid ester. The number average molecular weight of the water-soluble vinyl copolymer that is component b is usually 3,000 to 50,000 (GPC method, polyethylene glycol equivalent, the same applies hereinafter), but component b can be mixed with component a to be used as a dispersant for cement. From the viewpoint of the slump loss prevention effect of the hydraulic cement composition mixed in a fixed amount and the strength of the molded product obtained from the hydraulic cement composition, it is preferably 5,000 to 30,000. In the present invention, the cement dispersant that is mixed in a predetermined amount with respect to the solid content of cement is a mixture of component a and component b.
In terms of compatibility with the components and the effect of preventing slump loss when using this cement dispersant, the mixing ratio of both components is component a/component b = 98/2 to 75/25 (weight ratio).
is preferable, and 95/5 to 80/20 (weight ratio) is more preferable. The hydraulic cement composition according to the present invention contains 0.1 to 3.0 parts by weight of the above-described cement dispersant to 100 parts by weight of cement solid content. If the amount of cement dispersant blended is too small,
A sufficient dispersion effect and slump loss prevention effect cannot be obtained, and if the amount is too large, the paste may separate or cause curing failure. The hydraulic cement composition according to the present invention includes cement mortar and concrete obtained by adding and kneading sand, gravel, etc. in addition to cement paste, but it is especially suitable for highly water-reduced concrete. It has a remarkable effect. Specifically, the concrete obtained by adding the dispersant of the present invention at a water reduction rate of 18 to 40% with respect to the unit water volume of plain concrete without adding a cement dispersant and kneading the core of the present invention. It's one of the things you do. Furthermore, the hydraulic cement composition according to the present invention exhibits even more remarkable effects in high-strength to ultra-high-strength concrete, which is characterized by a small water/cement ratio and a small unit water amount. specifically,
Unit water volume is 120-170Kg/ ^m3 and water/cement ratio is
Concrete containing an appropriate amount of the cement dispersant of the present invention at 20 to 40% has outstanding features such as improved workability, workability, fluidity, and slump loss, and has a high compressive strength after hardening. It has the characteristics of high-strength to ultra-high strength concrete with a strength of around 1000 Kg/cm ² . In this case, if a part of the cement, for example 5 to 25% of the cement, is replaced with ultrafine siliceous powder, the characteristics of high-strength to ultra-high-strength concrete with even further improved fluidity and slump loss can be achieved. Become what you have. Examples of the cement used in such a hydraulic cement composition include various Portland cements, fly ash cement, blast furnace cement, alumina cement, silica cement, and various mixed cements. In addition to the above-described cement dispersant, the hydraulic cement composition according to the present invention further has the following properties:
Air amount regulators, setting accelerators, setting retarders, swelling agents, preservatives, etc. may be added. The structure of the present invention has been explained above, and the reason why the cement dispersant comprising component a and component b exhibits an excellent slump loss prevention effect is surmised as follows. That is, first, the component a preferentially adsorbs to the cement particles, imparts a charge to the cement particles, and the cement particles are dispersed. Next is component b, which has a larger molecular weight than component a, has a larger range of possible molecular forms in water, and has a bulkier group.
By adsorbing the component near component a and forming an adsorption layer, progress of physical aggregation due to contact between cement particles is inhibited. It is presumed that slump loss is prevented by charging the cement particles and sustaining the charge in this way. Examples are given below to make the structure and effects of the present invention more concrete, but the present invention is not limited to these Examples. <Examples, etc.> ● Production reference example (synthesis of water-soluble vinyl copolymer b-1) 80 parts of methacrylic acid (parts by weight, the same applies hereinafter), 40 parts of sodium methacrylsulfonate, and methoxypolyethylene glycol monomethacrylate (ethylene oxide) 260 parts (number of moles added = 9) were placed in a flask, and further 620 parts of water was added. Subsequently, 124 parts of a 30% aqueous sodium hydroxide solution was added to neutralize the methacrylic acid, and the pH of the system was adjusted to 8.5.
Next, the temperature of the system was maintained at 60°C in a hot water bath, and after the inside of the reaction system was sufficiently purged with nitrogen, 45 parts of a 20% aqueous solution of ammonium persulfate was added to start polymerization.
The reaction was continued for an hour to complete the polymerization. after that,
To neutralize the acidic decomposition product, 5 parts of a 30% aqueous sodium hydroxide solution was added to complete neutralization, and a product was obtained. 100 parts of the obtained product was concentrated using an evaporator to a concentration of 50 wt%, and then precipitated in 500 parts of isopropyl alcohol to remove unreacted monomers. Separate the precipitate by furnace,
Water-soluble vinyl copolymer b purified by vacuum drying
-1 was obtained. The water-soluble vinyl copolymer b-1 had a number average molecular weight of 4200 (GPC method, polyethylene glycol equivalent), a carboxyl value of 140, and a sulfur content of 2.0 wt% by elemental analysis. From these analysis results, the copolymerization ratio of water-soluble vinyl copolymer b-1 is methacrylic acid sodium salt/methallylsulfonic acid sodium salt/methoxypoly(n=9) ethylene glycol methacrylate = 25/10/65 (by weight) ratio). In the same manner, each water-soluble vinyl copolymer listed in Table 1 was obtained.

[Table] ● Examples 1 to 10, Comparative Examples 1 to 7 Preparation of concrete composition Ordinary Portland cement (mixture of equal amounts of ordinary Portland cement manufactured by Onoda Corporation and ordinary Portland cement manufactured by Sumitomo Corporation) at 320 kg/m ³ , Fine aggregate (Oigawa sand, specific gravity 2.62) is 859Kg/ ^m3 , coarse aggregate (Hachiyama crushed stone, specific gravity 2.65) is 975Kg/ ^m3 (Fine aggregate ratio =
47%), and the unit water amount was 163Kg/m ³ (water/cement ratio = 51%). In this case, the unit water amount of plain concrete is 200 Kg/m ³ (Comparative Example 10 described later), and the water reduction rate is 18.5% in each example. The cement dispersant was added to the cement in an amount of 0.55 to 2.0% by weight in terms of solid content so that the target slump value was 21 cm in each case. In addition, for air volume adjustment, the target air volume is 4± in each example.
Add an AE adjuster (manufactured by Takemoto Yushi Co., Ltd.) so that the concentration is 1%.
AE-200). All materials (kneaded amount: 40) were put into a 60° tilting mixer under the above mixing conditions as shown in Tables 2 and 3, mixed at 20 rpm for 3 minutes, and made into a uniform state. A composition was prepared. ... Test method Concrete tests were conducted on the prepared concrete compositions using the following method to measure slump and air content, their changes over time, and compressive strength. The results are shown in Table 2 (Examples) and Table 3 (Comparative Examples). ... Method The concrete composition was sampled immediately after mixing, and its slump and air content were measured.
Measured under controlled humidity of 20°C x 80% RH. Continue 2r.
The mixture was mixed at a rotational speed of pm for a certain period of time, sampled, and the slump and air amount were similarly measured.
Furthermore, the compressive strength of concrete sampled immediately after mixing was measured after 1 week and 4 weeks. In addition, measurements of slump, air volume, and compressive strength are based on JIS-A1101, JIS-A1128, and JIS-A1101, JIS-A1128, and JIS-
Conducted in accordance with A1108.

【table】

【table】

[Table] ● Comparative Example 8 A-1/b-1 = 90/10 (solid content weight ratio) cement dispersant was added to 100 parts of cement solid content.
Concrete compositions were prepared in the same manner as in Examples 1 to 10, except that 0.05 part was added, and JIS-
When the slump was measured in accordance with A1101, only hard concrete with a slump value of less than 5 cm and extremely poor fluidity was obtained. ● Comparative Example 9 A-1/b-1 = 90/10 (solid content weight ratio) cement dispersant was added at 3.5 parts per 100 parts of cement solid content.
Concrete compositions were prepared in the same manner as in Examples 1 to 10, except that part of the concrete was added, and JIS-A1101
When the slump was measured according to the following, the slump value was 25 cm or more, and the coarse aggregate such as gravel was completely separated, and homogeneous concrete could not be obtained. ●Comparative Example 10 (Preparation of plain concrete corresponding to Examples 1 to 10 and Comparative Examples 1 to 9) Ordinary Portland cement (mixture of equal amounts of ordinary Portland cement manufactured by Onoda Corporation and ordinary Portland cement manufactured by Sumitomo Corporation) at 320 kg/m ^3. Fine aggregate (Oigawa sand, specific gravity 2.62) is 886Kg/ ^m3 , coarse aggregate (Hachiyama crushed stone, specific gravity 2.65) is 937Kg/ ^m3 (fine aggregate ratio =
49%) and the unit water amount was 200Kg/m ³ (water/cement ratio = 62.5%) to prepare plain concrete. The slump of this plain concrete immediately after mixing is 18.8 cm, and the amount of air is
It was 1.3%. ● Examples 11 to 14, Comparative Examples 11 to 14 550 kg/m ³ of ordinary Portland cement (mixture of equal amounts of ordinary Portland cement manufactured by Onoda Corporation and ordinary Portland cement manufactured by Sumitomo Corporation), fine aggregate (Oigawa sand, specific gravity 2.62) 605Kg/m ³ , coarse aggregate (crushed stone from Okazaki, specific gravity 2.66) 1040Kg/m ³ (fine aggregate ratio =
37%), and the unit water amount was 165Kg/m ³ (water/cement ratio = 30%). The cement dispersant was added in each case so that the target slump value was 21 cm. Further, the air amount was adjusted by using an AE regulator (AE-200 manufactured by Takemoto Yushi Co., Ltd.) so that the target air amount was 4±1% in each case. All materials (kneading amount: 30) were put into a forced mixer under the above mixing conditions as shown in Tables 4 and 5, and mixed at 76 rpm for 90 seconds to obtain a uniform state, and the concrete composition was determined. I prepared something.・・Test method After sampling immediately after mixing, the concrete composition was transferred to a 60 tilt mixer and continued to be mixed at a rotation speed of 2 rpm for a specified period of time. Summer. The results are shown in Table 4 (Examples) and Table 5 (Comparative Examples).

【table】

[Table] ● Examples 15 to 18, Comparative Examples 15 to 17 450 kg/m ³ of ordinary Portland cement (mixture of equal amounts of ordinary Portland cement manufactured by Onoda Corporation and ordinary Portland cement manufactured by Sumitomo Corporation), fine aggregate (Oigawa sand, 726Kg/m ³ (specific gravity 2.62) and 1102Kg/m ³ (fine aggregate ratio = coarse aggregate (crushed stone from Okazaki, specific gravity 2.66)
40%), and the unit water amount was 155Kg/m ³ (water/cement ratio = 34.4%). The cement dispersant was added to each example so that the target slump was 8 cm, and the air content was less than 2%, making it a non-AE concrete.Other than that, the mixing method and testing method were as described in Examples 11 to 14 above. I did it in the same way as in the case. The results are shown in Table 6 (Examples) and Table 7 (Comparative Examples).

【table】

[Table] ● Examples 19 to 22, Comparative Examples 18 to 19 512 Kg/m ³ of ordinary Portland cement (mixture of equal amounts of ordinary Portland cement manufactured by Onoda Corporation and ordinary Portland cement manufactured by Sumitomo Corporation), and microsilica 940US (manufactured by Elkem Corporation). silica hume)
128/ ^m3 , 576 fine aggregate (Oigawa sand, specific gravity 2.62)
Kg/ ^m3 , coarse aggregate (Hachiyama crushed stone, specific gravity 2.65) 1034
Kg/m ³ (fine aggregate ratio = 36%), and the unit water volume is
The weight was set at 160Kg/ ^m3 . In this case, the W/(C+S) ratio is 25% and S/(C+S) is 20%. [However, W: unit amount of water C: unit amount of cement S: unit amount of silica hume] The dispersant for cement was added so that the target slump value was 21 cm in each case, and the amount of air was 2.
As non-AE concrete of less than %, others,
The kneading method and test method are as described in Example 11~
This was done in the same manner as in case 14. The results are shown in Table 8 (Examples) and Table 9 (Comparative Examples).

【table】

[Table] <Effects of the Invention> As is clear from the results of each Example with respect to each Comparative Example, the present invention described above contains a cement dispersant with excellent water reduction performance, and when highly water reduced. Even in the case of dispersion, the dispersion fluidity exhibits excellent dispersion fluidity while providing an appropriate amount of air and good compressive strength, and there is also an extremely small change in the dispersion fluidity over time.

Claims (1)

[Claims] 1. 0.1 to 0.1 to 0.1 to 100 parts of a cement dispersant consisting of the following components a and b to 100 parts by weight of cement solid content.
A hydraulic cement composition containing 3.0 parts by weight. Component a: alkali metal salt or alkaline earth metal salt of formalin condensate of aromatic sulfonic acid,
Or an alkali metal salt or alkaline earth metal salt of a formalin condensate of N-sulfomethylated melamine. Component b: It contains the following monomers A, B and C, and the copolymerization ratio of the monomers is A/B/C=57-5/3-25/85-40 (weight ratio )
A water-soluble vinyl copolymer. [However, R ¹ , R ² , R ³ are H or CH ₃ . R ⁴ is an alkyl group having 1 to 3 carbon atoms. X is -SO ₃ M ² or [Formula] M ¹ and M ² are alkali metals, alkaline earth metals, ammonium, or organic amines. n is an integer from 5 to 50. ] 2 component a/component b = 98/2 to 75/25 (weight ratio)
The hydraulic cement composition according to claim 1. 3. The hydraulic cement composition according to claim 1 or 2, wherein the formalin condensate of aromatic sulfonic acid is a formalin condensate of naphthalenesulfonic acid. 4. The hydraulic cement composition according to claim 1, 2 or 3, wherein the hydraulic cement composition is concrete. 5 Water reduction rate (vs. plain concrete) is 18-40
% of concrete. 5. The hydraulic cement composition of claim 4. 6. The hydraulic cement composition according to claim 4, which is concrete having a unit water amount of 120 to 170 Kg/m ³ and a water/cement ratio of 20 to 40%. 7. The hydraulic cement composition according to claim 6, which is concrete mixed with ultrafine siliceous powder.