JPS61146747A - Cement dispersion - 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 a dispersant for cement or cement mixtures, and more particularly to a dispersant for cement or cement mixtures. The present invention relates to a cement dispersant that prevents deterioration caused by cement dispersion and improves its workability and workability.

[Conventional technology]

Conventionally, commonly used cement dispersants include lignin sulfonic acid (salt), oxycarboxylic acid, naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate, polycarboxylic acid, and the like.

A cement mixture made by mixing cement, water, sand, gravel, and admixtures (agents) gradually loses fluidity as the physical and chemical agglomeration of cement particles progresses over time after mixing. , construction efficiency and workability deteriorate over time.

For this reason, cement compounds have a workable time (pot life)
It has the disadvantage of being 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 (biles, balls, 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, and the pumping will be difficult when the pumping is resumed. There are also many problems such as sudden rise or blockage.

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 cement from chemically coagulating, hardening retarders such as oxycarboxylate or genin sulfonate are added to prevent cement particles from physically coagulating. This is a method that attempts to prevent this.

[Problem that the invention seeks to solve]

However, the above-mentioned method causes serious problems such as delayed setting of the concrete, and has drawbacks such as a decrease in strength and durability because the fluidizing agent remains locally.

As described above, these conventional methods for preventing reduction in workability of cement mixtures have a number of problems and cannot be said to be satisfactory.

[Means for solving problems]

As a result of intensive research to improve the drawbacks of the conventional methods described above, the present inventors found that a combination of a sulfonated melamine resin or its salt having a viscosity higher than a specific viscosity, an AE water reducer, a high performance water reducer, or a fluidizing agent. By using a cement dispersant whose essential component is a mixture with one or more cement admixtures, it is possible to maintain the fluidity of the cement mixture for a long time without delaying the setting time. The present invention has been completed by discovering that the workability and workability of cement mixtures can be improved without delaying the start time of finishing and marking.

That is, the present invention provides a cement dispersant characterized by having as an essential component a blend of the following components (a) and (2).

(a) A sulfonated melamine resin or a salt thereof whose viscosity in a 20% aqueous solution is 15 cP or more at 20° C. and pi (8,5).

(b) Cement admixture of one or more of AE water reducer, high performance water reducer or superplasticizer.

The sulfonated melamine resin or its salt according to the present invention is particularly preferably one having a molecular weight distribution characteristic FIO of 0,000 or more of 25% by weight or more.

The molecular weight distribution of the sulfonated melamine resin or its salt according to the present invention is determined by fractionation and collection by gel permeation chromatography using polystyrene sulfonic acid sodium salt as a reference material. That is, the term rFloo used herein indicating molecular weight distribution characteristics,
000 or more" refers to gel permeation chromatography with an average molecular weight of 100,000 in gel permeation chromatography measurements using a gel permeation chromatography column TSKgelG6000SW preparative use (manufactured by Toyo Soda Kogyo ■) and TSKgelG3000S & 4 preparative use (same as above). The fraction of sodium polystyrene sulfonate standard sample (manufactured by Showa Denki Kogyo ■) was collected up to the point where it flowed out, and the amount of sulfonated melamine resin or its salt in this fraction was measured. Or it is expressed as a weight percentage based on the amount of salt.

20 of the sulfonated melamine resin or its salt according to the present invention
The viscosity of the % aqueous solution is 15 cP at 20°C and pH 8.5.
When the particle size is smaller and the molecular weight distribution characteristic FIO0,000 or more is less than 25% by weight, the cement particles are well dispersed, but the slump loss prevention property decreases, and the concrete performance considering dispersibility and slump loss prevention performance is reduced. becomes lower.

In the present invention, the viscosity of a 20% aqueous solution of sulfonated melamine resin or its salt is 15 at 20°C and pH 8.5.
cP or more, and if the molecular weight distribution characteristic FIO0°000 or more is 25% by weight or more, the slump loss prevention performance will improve, but considering practical workability, a 20% aqueous solution viscosity is 1.000 cP, molecular weight distribution Characteristic FIO0,000
Above, up to 901iii% is preferable.

In the present invention, the molar ratio of bound formaldehyde to melamine in the sulfonated melamine resin or its salt having a viscosity higher than a specific viscosity is not particularly limited, but in general, 2 to 4 moles of bound formaldehyde per mole of melamine is suitable. It is. Furthermore, the molar ratio of the bonded sulfone group to melamine is not particularly limited, but generally the bonded sulfone group is 0 per mole of melamine.
．． 9 to 1.2 mol is suitable.

- The sulfonated melamine resin obtained in this way, which has a viscosity higher than a specific viscosity, can be used as a cement dispersant as it is, but if necessary, it can be further neutralized with an alkaline substance before use. . Examples of alkaline substances include hydroxides, chlorides, and carbonates of monovalent metals such as lithium, sodium, and potassium, and divalent metals such as calcium and magnesium, ammonia, and organic amines.

In the present invention, (AE water reducing agent, high performance water reducing agent, or fluidizing agent used as a BL component) includes a polyol complex, oxycarboxylic acid or its salt, polycarboxylic acid or its salt, ligninsulfonic acid or its salt, Melamine sulfonic acid formalin condensate or its salt, taleosote oil sulfonic acid formalin condensate or its salt, naphthalene sulfonic acid formalin condensate or its salt, sulfonation in which the viscosity of a 20% aqueous solution is less than 15 cP at 20°C and pH 8.5 Examples include melamine resin or its salt, polyoxyethylene alkylaryl ether type, etc. Among these, lignin sulfonic acid or its salt, naphthalene sulfonic acid formalin condensate or its salt, polycarboxylic acid or its salt, or 20% The viscosity of the aqueous solution is 20
A sulfonated melamine resin or a salt thereof having a value of less than 15 cP at a temperature of 8.5°C and a pH of 8.5 is preferred.

In the present invention, the blending ratio of the above-mentioned (Al component and (b) component) is preferably 1:99 to 80:20 (weight ratio).

The method of adding the cement dispersant according to the present invention to a cement mixture can be in the form of an aqueous solution, powder, or granules.
It can be added during tri-blending with cement, dissolving in mixing water, or at the start of mixing of the cement mixture, i.e. at the same time as water is poured into the cement, or immediately after water is poured until the end of mixing of the cement mixture. It is also possible to add it to the cement mixture once it has been mixed. Further, the cement dispersant of the present invention can be added in its entirety at once, or added in several portions.

The appropriate amount of the cement dispersant of the present invention to be added is 0.02 to 2% by weight based on the weight of cement.

If the content is less than 0.02% by weight, the workability retention effect of the cement mixture will be poor, and if it exceeds 2% by weight, it will be economically disadvantageous or the strength will decrease, which is not preferable.

The cement dispersant of the present invention includes cement additives (materials) other than the above (al component and component (b)), such as AE agents, (ultra) retarders, early strengthening agents, accelerators, foaming agents, blowing agents, and extinguishers. foaming agent,
Water retention agent, thickener, self-leveling agent, waterproofing agent, rust preventive agent, coloring agent, anti-mold agent, crack reducing agent, polymer emulsion, its low surfactant, water-soluble polymer, swelling agent (material), glass fiber, fly ash, cinder ash, tarinker ash, husk ash,
It is also possible to use it in combination with blast furnace slag, silica fume, silica powder, etc.

These cement additives (materials) include "Concrete Engineering" by Takakazu Maruyasu and Shun Mizuno, Coronasha, 1981 edition, "Cement Concrete Knowledge" edited by Junji Yamada, (
Generally known are those described in the Economic Research Institute, 1981 edition, or "New Surfactant Comprehensive Data Collection" written by Ken Hattori-9 Higashi Toshihiro, Business Development Center Publishing, pages 941-958, etc. ing.

An example is as follows.

AH agent; resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, ABS
5LAS, alkanesulfonate, polyoxyethylene alkyl ether, alkyl ether sulfonate or phosphate, lignin sulfonate, protein material,
alkenyl sulfosuccinic acid, α-olefin sulfonate, etc.

(Trend) 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 foaming Agents and blowing agents: Aluminum powder, resin soaps, synthetic surfactants, hydrolyzed protein antifoaming agents; Mineral oils: Seed oils, liquid paraffin oils: Animal and vegetable oils, sesame oil, castor oil, alkylene oxide adducts of these fatty acids Nioleic acid, stearic acid fatty acid ester diethylene glycol laurate, glycerin monolysyllate, alkenyl succinic acid derivative, sorbitol monolaurate, sorbitol trioleate, polyoxyethylene monolaurate, polyoxyethylene sorbitol monolaurate, natural wax Alcohol-based: octyl alcohol, hexadecyl alcohol, acetylene alcohol, glycols, polyoxyalkylene glycolamide-based: polyoxyalkyleneamide, acrylate polyamine phosphate ester, tributyl diphosphate, sodium octyl phosphate, metal soap, nialium stearate, calcium Oleate silicone type dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane, fluorosilicone oil waterproofing agents; Fatty acids (salts), fatty acid esters, fats and oils, silicone, paraffin, asphalt, wax, etc. rust inhibitors; Nitrate, phosphate, zinc oxide, etc. Crack reducers: Polyoxyalkyl ether polymer emulsions; Other surfactants: Anionic, cationic, nonionic and amphoteric surfactants Water-soluble polymers: Carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxy Cellulose derivatives such as propylcellulose, polyvinyl alcohol, starch, starch phosphate, sodium alginate, gelatin, sodium polyacrylate, polyacrylamide, polyoxyethylene or polyoxypropylene polymers or copolymers thereof, amino groups in the molecule. A copolymer of acrylic acid and its quaternary compound expanding material; Ettringite type, lime type It is also possible to add the above-mentioned additive (material) after adding the above-mentioned dispersant, or to add the dispersant of the present invention after adding the above-mentioned additive (material). There are methods of addition such as adding the dispersant 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 asche cement, silica cement, silica hieme blended cement, alumina cement, expansive cement, regulated 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 (lightweight) sand (li), natural lightweight aggregate Used in the present invention Mixing of Shiroru Hydraulic Cement Compound (Ri1
) is “Concrete Engineering Handbook” published by Asakura Shoten,
The mixture described in "Concrete Handbook" published by Gihodo etc. can be used.

[Effect]

The mechanism of prevention of decrease in workability in cement formulations containing the cement dispersant of the present invention is thought to be as follows.

That is, after kneading, cement particles in a cement mixture formed by kneading cement, water, sand, gravel, and a dispersant undergo chemical aggregation due to a hydration reaction and physical aggregation due to interparticle attraction. Gradual loss of liquidity. Therefore, by dispersing cement so that the cement particles are in a soft agglomerated state, the above-mentioned decrease in workability can be prevented.

In the cement dispersant of the present invention, the sulfonated melamine resin or its salt having a viscosity higher than a specific viscosity, as well as the sulfone group and carboxyl group contained in the AE @ water agent, high performance water reducing agent, and fluidizing agent are used. It adsorbs to the cement particles, negatively charges the entire cement particles, creates a repulsive force between the particles, and provides dispersibility. However, the viscosity of a 20% aqueous solution is 1
A sulfonated melamine resin or a salt thereof having a value of 5 cP or more (20° C., GIEI 8.5) forms a soft agglomerated state without highly dispersing cement particles having repulsive force or highly agglomerating them. Furthermore, specific molecular weight distribution,
In other words, a sulfonated melamine resin or a salt thereof having a molecular weight distribution characteristic F100.000 or more of 25% by weight or more can form a better soft aggregation state. Furthermore, the speed of transition from the soft agglomerated state to the agglomerated state can be supplementarily slowed down by the stable entrained air.

It is presumed that the synergistic effects of these three are responsible for maintaining the workability of the cement mixture for a long time.

〔Effect of the invention〕

Since the present invention makes it possible to maintain workability for a long time without causing concrete agglomeration delay, the cement dispersant according to the present invention is specifically used in various applications.

For example, it is used as a concrete pumping aid. 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 cement dispersant 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 the pumping from increasing when pumping is restarted after pumping is interrupted. This makes it possible to significantly improve the effectiveness of the pumping operation.

Further examples include grouting aids in cement milk or mortar, cement formulations cast by tremie tubes, 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.

〔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 9 and Comparative Examples 1 to 6 Using the dispersants of the present invention shown in Table 2, product numbers 1 to 70, and comparative dispersants of product numbers 8 to 13, an experiment was conducted to determine the workability retention effect of concrete in °C. . The following materials were used for concrete, and the mixture was as shown in Table 1. Workability was measured by the slump test of JIS A 1101 and the air volume test of JIS A 1128. Further, the setting time measurement test was conducted according to ASTM C403-65T, and the compressive strength test was conducted according to JIS A 1108.

Experimental conditions are shown in Table 3, and test results are shown in Tables 4, 5, and 6.

Najirisha Cement (C): Ordinary Portland cement (specific gravity 3.
17) Fine aggregate (S): Coarse aggregate (specific gravity 2.57)
G): Hidaka grade (specific gravity 2.59) water (W) AE agent: Vinsol (manufactured by Nuke Kagaku) The AE agent was used as necessary.

Method for preparing concrete Method-1: Dissolve the cement dispersant in mixing water in advance, mix 50β concrete for 2 minutes at 20°C using a 1001 tilting mixer, and then mix at low speed at 4 rpa+. At the same time, slump was measured at predetermined times.

Method-2: The same procedure as Method-1 was carried out except that the cement dispersant was added separately from the mixing water.

Teikin No. 1 and 3 Table ratio: Kawa Cement XX% (II!!) Type Table 4 Table 6 (Note) *: From the results of standard curing Tables 4, 5, and 6, It is clear that the cement dispersant of the present invention provides extremely excellent effects in terms of slump retention and setting time.

Claims (1)

[Scope of Claims] 1. A cement dispersant characterized by comprising as an essential component a blend of components (a) and (b) shown below. (a) A sulfonated melamine resin or a salt thereof whose viscosity in a 20% aqueous solution is 15 cP or more at 20° C. and pH 8.5. (b) Cement admixture of one or more of AE water reducer, high performance water reducer or superplasticizer. 2. The cement dispersant according to claim 1, wherein the sulfonated melamine resin or its salt as component (a) has a molecular weight distribution characteristic F100,000 or more of 25% by weight or more. 3. Component (b) is ligninsulfonic acid or its salt, naphthalenesulfonic acid formalin condensate or its salt, polycarboxylic acid or its salt, or the viscosity of the 20% aqueous solution is 2.
3. The cement dispersant according to claim 1 or 2, which is a sulfonated melamine resin or a salt thereof, which has a sulfonated melamine resin or a salt thereof, which has a value of less than 15 cP at 0° C. and pH 8.5. 4. The cement dispersant according to claim 1 or 2, wherein component (b) is ligninsulfonic acid or a salt thereof. 5. The cement dispersant according to claim 1 or 2, wherein the component (b) is a naphthalene sulfonic acid formalin condensate or a salt thereof. 6. The blending ratio of component (a) and component (b) is 1:99-8
The cement dispersant according to claim 4 or 5, which has a weight ratio of 0:20.