JPS61281054A - Concrete admixing agent - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an admixture for cement or cement mixtures, and more particularly to an admixture for concrete, mortar or paste which is a hydraulic cement mixture. The present invention relates to a cement admixture that maintains a certain amount of air, prevents a decrease in workability over time, and improves workability and workability.

[Conventional technology]

Conventionally, commonly used cement admixtures include ligninsulfonic acid (salt), oxycarboxylic acid, naphthalenesulfonic acid formalin m, melamine sulfonic acid formalin condensate, polycarboxylic acid, and the like.

Cement mixtures made by mixing cement, water, sand, gravel, and admixtures (agents) undergo physical and chemical aggregation of cement particles over time after mixing, and entrainment in the mixture. The amount of air decreases, fluidity is gradually lost, and workability and workability deteriorate over time. For this reason, cement compositions have the disadvantage that their workable time (pot life) is limited. Further, after being mixed, the cement mixture is often transported to the casting site by an agitator truck (ready concrete mixer truck), and the time required for transportation varies greatly depending on the transportation distance, traffic congestion, etc. For this reason, at the pouring site, the fluidity differs depending on the agitator car, making it extremely difficult to obtain consistent workability.

In the production of concrete factory products (piles, poles, pipes, etc.), the decline in concrete fluidity over time is a similar problem.

For example, when pumping a cement mixture, if the pumping is temporarily interrupted due to a lunch break or setup change, and then the pumping is restarted, the fluidity of the cement mixture in the piping will decrease, further reducing the amount of entrained air. As a result, workability is significantly reduced, and there are many problems such as sudden increase in pumping or blockage when pumping is restarted.

In order to solve these problems, various methods have been devised to prevent the decrease in workability of cement mixtures. For example, in order to prevent chemical agglomeration of cement, a large amount of hardening retarders such as polycarboxylic acid salts, oxycarboxylic acid salts, and lignin sulfonates are added, and high-performance water reducing agents and superplasticizers are granulated. This method attempts to prevent physical agglomeration of cement particles by adding an excessive amount of a cement dispersant. In particular, many attempts have been made to use these methods using lignin sulfonate.

[Problem that the invention seeks to solve]

However, in all of the above methods, the amount of air in the concrete becomes excessive, resulting in a decrease in strength. For this reason, for example, various attempts have been made to reduce the amount of low-molecular-weight substances using lignin sulfonate, such as through fractionation operations, and to modify the lignin sulfonate by air oxidation. In addition, attempts have been made to adjust the molecular weight of polycarboxylic acid salts by fractionation and to reduce air entrainment by examining manufacturing conditions, but these efforts have not been fully satisfactory. Furthermore, there have been many studies using antifoaming agents such as silicone-based, higher alcohol-based, and phosphate-based antifoaming agents, but these have hardly produced a satisfactory effect in reducing the amount of air in concrete. In particular, if the amount of air is forcibly reduced by a method such as increasing the amount of conventional antifoaming agent added, the amount of fine air that is effective for freeze-thaw resistance will decrease.1. Durability is extremely reduced.

As described above, in the prior art, when a dispersant with air-entraining properties is used, there are many problems in the amount of entrained air and freeze-thaw resistance.

[Means for solving problems]

The inventors of the present invention have conducted intensive research to improve the drawbacks of the conventional methods described above. By using a concrete admixture made of the specific compound shown below, the fluidity of the cement mixture can be maintained for a long time, and The present inventors have discovered that by preventing excessive entrainment of air, the workability and workability of the cement mixture can be improved without reducing the strength or impairing the durability of the cement mixture, leading to the completion of the present invention.

That is, the present invention contains the following components (a) and (b) as essential components, and the solid coulometric ratio of component (a)/component (b) is 99.9910.01 to 90/10. The present invention provides a concrete admixture characterized by the following.

(a) Component cement dispersant; (b) component nonionic surfactant containing one or more compounds represented by general formula (I);

R1-C-0-R2-R3- (I) (wherein, Ri is a saturated or unsaturated aliphatic hydrocarbon group having 14 to 22 carbon atoms, R2 is an alkylene oxide adduct that essentially includes propylene oxide, R8 is hydrogen or an alkyl group having 1 to 4 carbon atoms.) The present invention further contains the following component (c) as an essential component in addition to the above component (a) and (bl component), (component (a) + The present invention also provides a concrete admixture characterized in that the solid content weight ratio of component (b)/component (c) is from 99.9910.01 to 9515.

Component (c) Sulfate-based anionic surfactant As component (a) of the present invention, various known cement dispersants can be used. In general, genin sulfonic acid (
Salt) or a modified product thereof, polycarboxylic M (salt), and one or a mixture of two or more of naphthalenesulfonic acid formalin condensates are preferred. Particularly suitable is a dispersant that essentially contains ligninsulfonic acid (salt), a modified product thereof, or a polycarboxylic acid (salt). Lignosulfonic acid (
Examples of modification of the salt) include oxidation reaction, polymerization, and introduction of functional groups under various known conditions.

Although the cement dispersant of the present invention can be used as an acid,
Generally, it is preferable to use it in the form of a salt, and the cations formed include Li + Na + LCa + M g +
Examples include N H# I alkanolamine, N-alkyl substituted polyamine, ethylene diamine, polyethylene polyamine, polyethylene imine, and alkylene oxide adducts thereof.

The (bl component of the present invention) is a non-containing compound containing one or more alkylene oxide adducts of a saturated or unsaturated fatty acid having 14 to 22 carbon atoms represented by the general formula (I), with propylene oxide being essential. It is an ionic surfactant.The alkylene oxide adduct is preferably an alkylene oxide adduct in which 5 to 50 moles of propylene oxide are essential.A typical method for producing the compound represented by the general formula (I) is teeth,
There is a method of adding alkylene oxide to a fatty acid, and at this time, a small amount of diester form of the alkylene oxide adduct can also be included.

In addition to the compound represented by the general formula (I), component (b) also includes an alkylene oxide adduct of an alcohol having 1 to 3 carbon atoms represented by the following general formula (II), which essentially includes ethylene oxide. A species or a mixture of two or more species may be used.

R4-0-Rs-H -- (II) (In the formula, R4 is an alkyl group having 1 to 3 carbon atoms, and R6 is an alkylene oxide adduct that essentially includes ethylene oxide.) At this time, the above-mentioned general The solid content weight ratio of the compound represented by formula (I) and the compound represented by general formula (II) is 9515.
~70/30 is preferred. Preferred compounds represented by the general formula (II) are ethylene oxide 1-50
Examples include those in which 1 to 3 moles of propylene oxide are added to the terminal.

Component (c) of the present invention is a sulfate-based anionic surfactant, specifically, sulfates (salts) of α-olefins having 14 to 22 carbon atoms, aliphatic surfactants having 5 to 21 carbon atoms, Alternatively, sulfates (salts) of aromatic alcohol adducts with 1 to 5 moles of ethylene oxide may be used, and one or a mixture of two or more of these may be used. (c) The ratio of components is too large, that is, the ratio of the sum of components (a) and (b) to the ratio of component (c) ((a)
) + (b) ) / (c) is less than 9575, which is not preferable because the amount of air in the concrete increases or the amount of fine air decreases.

The concrete admixture according to the present invention can be added to a cement mixture in the form of an aqueous solution, an aqueous dispersion, or a powder or granules. It is possible to add it at the same time as the mixing of the cement mixture, that is, at the same time as pouring water into the cement, or immediately after pouring water until the end of mixing of the cement mixture, and it is also possible to add it to the cement mixture once it has been mixed. . Further, the admixture of the present invention can be added in its entirety at once or in several parts.

In addition, (al component and (b) component, and if necessary, (c1 component) may be mixed in advance, or after blending a part of it with cement or a cement mixture, or a part of it with a cement or cement mixture. It is also possible to mix and knead the ingredients and then mix the remaining ingredients.

In addition, other cement additives (materials), such as superplasticizers, high performance water reducers, (ultra) retarders, early strength agents, accelerators, water retention agents,
Thickeners, self-leveling agents, waterproofing agents, rust preventives, coloring agents, anti-mold agents, crack reducing agents, polymer emulsions, other surfactants, water-soluble polymers, swelling agents (materials) It is also possible to use it in combination with , glass fiber, fly ash, Xingu ash, tallinker ash, husk ash, blast furnace slag, silica hume, silica powder, etc.

These cement additives (materials) include "Concrete Engineering" by Takakazu Maruyasu and Shun Mizuno, Coronasha, Showa, 57.
2015 edition, “Knowledge of Cement Concrete” edited by Junji Yamada,
The ones described in the Economic Research Institute, 1982 edition, or "New Surfactant Comprehensive Data Collection" written by Ken-1 Higashi Toshihiro, Management Development Center Publishing, pages 941-958 are generally known. It is being

An example is as follows.

(Ultra) retardant; lignin sulfonate, oxycarboxylate, magnesium silicofluoride, phosphoric acid and its salts or esters, boric acids, aminocarboxylic acids and their salts, alkali-soluble proteins, polyacrylic acid compounds, Polyhydric alcohol fast-strengthening agents such as humic acid, tannic acid, phenol, and glycerin.
Accelerators; chlorides such as calcium chloride, iron chloride, magnesium chloride, sulfates, potassium hydroxide, sodium hydroxide, carbonates, thiosulfates, formic acid and formates, alkanolamines, alumina cement, calcined alunite waterproofing agents : Rust preventive agents such as fatty acids (salts), fatty acid esters, fats and oils, silicone, paraffin, asphalt, and wax; Crack reducers such as nitrites, phosphates, and zinc oxide; Polyoxyalkyl ether polymer emulsions; Water-soluble polymers; Cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, starch, starch phosphate, sodium alginate, gelatin, sodium polyacrylate, polyacrylamide, polyoxyethylene or polyoxypropylene polymers, or the like. Copolymers of acrylic acid having amino groups in the molecule and their quaternary compound expansion materials; It is also possible to add ettringite-based, lime-based, and AH agents that entrain high quality air to improve freeze-thaw resistance. It is.

Examples of such AU agents include resin soaps and alkenyl succinates.

The order of addition of the above cement additive (material) and the concrete admixture of the present invention is not particularly limited; for example, the above additive (material) may be added after the admixture of the present invention is added, or It is also possible to add the admixture of the present invention after adding the above additives (materials), and there are other methods of addition such as adding the above additives (materials) and the admixture of the present invention at the same time.

Further, examples of materials used in the hydraulic cement mixture that can be used in the present invention include the following.

Cement: Portland cement, blast furnace cement, fly ash cement, silica cement, silica hume blended cement, alumina cement, expansive cement, regulated set cement, colloidal cement, white cement,
Oil well cement aggregate: river sand (li), land sand (li), sea sand (li), crushed sand (li), slag sand (li), artificial (light) sand (li), natural lightweight aggregate Used in the present invention For the formulation (mixture) of the wet hydraulic cement mixture, the formulations described in "Concrete Engineering Handbook" published by Asakura Shoten, "Concrete Handbook" published by Gihodo, etc. can be used.

The appropriate amount of the concrete admixture according to the present invention is 0.005 to 5% by weight of solids based on the weight of cement. 0
．． If it is less than 0.5% by weight, the workability retention effect of the cement mixture will be poor, and if it exceeds 5% by weight, it will be economically disadvantageous or the strength will decrease, which is not preferable.

〔Effect of the invention〕

Even if a dispersant with a high air entrainment property is used according to the present invention,
The concrete admixture according to the present invention is specifically used in various applications because it has become possible to maintain an appropriate amount of air with excellent freeze-thaw resistance and maintain the workability of concrete for a long time.

For example, it is used as a pumping aid for concrete. Cement mixtures are increasingly being placed by pumping, but as mentioned above, if pumping is temporarily interrupted due to work lunch breaks, changeovers, or mechanical failures, if the interruption is prolonged, pumping may become impossible. The workability of the concrete in the piping has decreased, causing problems such as a sudden increase in pumping pressure when pumping is restarted, and blockages.

However, when the concrete admixture according to the present invention is added, the workability of concrete is kept constant, a decrease in fluidity is prevented, and it is possible to prevent an increase in pumping when restarting pumping after pumping is interrupted. This makes it possible to significantly improve the effectiveness of the pumping operation.

Further examples include grouting aids for cement milk or mortar, cement mixtures cast into tremie pipes, underwater concrete, concrete for continuous underground walls,
Spraying is also effective for maintaining fluidity and preventing material separation in concrete, centrifugally formed concrete, vibration compacted concrete, etc.

Furthermore, it has become possible to add a large amount of an inexpensive dispersant.

As another example, by adding a large amount of a dispersant, it has become possible to significantly reduce the unit amount of water and produce ultra-high strength concrete with suppressed air entrainment.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 11 and Comparative Examples 1 to 8 Any compound was selected from component (a) shown in Table 2, component (b) shown in Table 3, and component (c) shown in Table 4, and The concrete admixtures shown in the table were prepared and experiments were conducted on the workability retention effect and freeze-thaw resistance of concrete. The following materials were used for concrete, and the mixture was as shown in Table 1. Measurement of workability is based on JIS A
1101 slump test and JIS A 1128 air volume test.

In addition, the compressive strength test was conducted in accordance with JIS A 110B.

The experimental conditions are shown in Table 5, and the test results are shown in Tables 6 and 7.

Fine aggregate (S): Coarse aggregate from Kinoyo (specific gravity 2.57) (
G): Crushed stone from Takarazuka (specific gravity 2.59) Water (!A) Table 7 Note *1: Standard curing From the results in Tables 6 and 7, it is clear that the concrete admixture of the present invention has a slump residual rate and an appropriate air content. It is clear that it has extremely excellent effects in terms of volume retention and freeze-thaw resistance.

Claims (1)

[Claims] 1. Contains the following components (a) and (b) as essential components, and has a solid content weight ratio of component (a)/component (b) of 99.
．． A concrete admixture characterized by having a ratio of 99/0.01 to 90/10. (a) Component cement dispersant; (b) component nonionic surfactant containing one or more compounds represented by general formula (I); R_1-C-O-R_2-R_3...(I) (In the formula, R_1 is a saturated or unsaturated aliphatic hydrocarbon group having 14 to 22 carbon atoms, and R_2 is an alkylene oxide adduct that essentially includes propylene oxide. , R_3 is hydrogen or an alkyl group having 1 to 4 carbon atoms.) 2. The nonionic surfactant of component (b) has the above general formula (
The concrete admixture according to claim 1, which contains one or more compounds represented by the following general formula (II) in addition to the compound represented by I). R_4-O-R_5-H...(II) (In the formula, R_4 is an alkyl group having 1 to 3 carbon atoms, and R_5 is an alkylene oxide adduct that essentially includes ethylene oxide.) 3. Component (b) The solid content weight ratio (I) of the compound represented by the general formula (I) and the compound represented by the general formula (II) in
The concrete admixture according to claim 1 or 2, wherein /(II) is from 95/5 to 70/30. 4. Component (a) is one or a mixture of two or more of ligninsulfonic acid (salt) or a modified product thereof, polycarboxylic acid (salt), and naphthalenesulfonic acid formalin condensate. Concrete admixture according to any one of paragraph 3. 5. The concrete admixture according to any one of claims 1 to 3, wherein component (a) essentially contains ligninsulfonic acid (salt) or a modified product thereof. 6. The concrete admixture according to any one of claims 1 to 3, wherein component (a) essentially contains a polycarboxylic acid (salt). 7. The compound according to any one of claims 1 to 6, wherein R_2 of the compound represented by the general formula (I) is an alkylene oxide adduct in which 5 to 50 moles of propylene oxide are essentially added. Concrete admixture. 8. According to any one of claims 1 to 7, R_5 of the compound represented by the general formula (II) is a compound in which 1 to 50 moles of ethylene oxide are added and then 1 to 3 moles of propylene oxide are added. Concrete admixtures listed. 9. Contains the following (a) component, (b) component, and (c) component as essential components, {(a) component + (b) component}/
Solid content weight ratio of component (c) is 99.99/0.01-9
A concrete admixture characterized by being 5/5. (a) Component cement dispersant; (b) component nonionic surfactant containing one or more compounds represented by general formula (I); ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, R_1 is a saturated or unsaturated aliphatic hydrocarbon group having 14 to 22 carbon atoms, and R_2 is an alkylene oxide addition with propylene oxide as essential. (R_3 is hydrogen or an alkyl group having 1 to 4 carbon atoms.) (c) component sulfate-based anionic surfactant 10, component (b) component nonionic surfactant having the above general formula (I ) The concrete admixture according to claim 9, which contains one or more compounds represented by the following general formula (II) in addition to the compound represented by formula (II). R_4-O-R_5-H...(II) (In the formula, R_4 is an alkyl group having 1 to 3 carbon atoms, and R_5 is an alkylene oxide adduct that essentially includes ethylene oxide.) 11. Component (b) The solid content weight ratio of the compound represented by general formula (I) and the compound represented by general formula (II) in
)/(II) is 95/5 to 70/30, the concrete admixture according to claim 9 or 10. 12. Component (a) is one or a mixture of two or more of ligninsulfonic acid (salt) or a modified product thereof, polycarboxylic acid (salt), and naphthalenesulfonic acid formalin condensate. Concrete admixture according to any one of paragraph 11. 13. Claims 9 to 11 in which the component (a) essentially contains ligninsulfonic acid (salt) or a modified product thereof
A concrete admixture as described in any one of paragraphs. 14. The concrete admixture according to any one of claims 9 to 11, wherein component (a) essentially contains a polycarboxylic acid (salt). 15. R_2 of the compound represented by the general formula (I) is an alkylene oxide adduct in which 5 to 50 moles of propylene oxide are essentially added, according to any one of claims 9 to 14. Concrete admixture. 16. According to any one of claims 9 to 15, wherein R_5 of the compound represented by general formula (II) is a compound in which 1 to 50 moles of ethylene oxide are added and then 1 to 3 moles of propylene oxide are added. Concrete admixtures listed. 17. Component (c) is a sulfate (salt) of an α-olefin having 14 to 22 carbon atoms, a sulfate (salt) of an adduct of 1 to 5 moles of ethylene oxide to an aliphatic or aromatic alcohol having 5 to 21 carbon atoms The concrete admixture according to any one of claims 9 to 16, which is one type or a mixture of two or more types.