JPH024545B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a novel cement admixture composition, and more particularly to a polycarboxylic acid cement admixture composition containing an AE agent. (Prior Art) Generally, when producing concrete, mortar, paste, etc. using cement, admixtures called dispersants, water reducers, or fluidizers are used. This admixture is expected to have the following effects. That is, (1) increasing the workability of unset cement mixtures;
Also, if the workability is the same, the amount of water used will be reduced. (2) Since the amount of water used can be reduced, the strength after construction is increased as a result. Also, if the strength is the same, the amount of cement used can be reduced. (3) Increase watertightness, etc. Conventionally, such admixtures include ligninsulfonic acid, oxycarboxylic acid, β-naphthalenesulfonic acid/formalin condensate, melamine sulfonic acid/formalin condensate, and olefin.
α,β-unsaturated dicarboxylic acid copolymer system (hereinafter referred to as
Polycarboxylic acid admixtures (sometimes simply referred to as polycarboxylic acid-based admixtures) are known, and among them, polycarboxylic acid-based admixtures are known to exhibit good dispersion fluidity with a small amount added and also have excellent slump retention. Recently,
Research is being actively carried out (for example, the
(No. 18215, No. 53-38095, Special Publication No. 58-213663, etc.) (Problems to be Solved by the Invention) However, since polycarboxylic acid cement admixtures are generally non-air-entraining, they are not necessarily suitable for use as AE-type water reducers that require air-entraining properties; There is an operational difficulty in that an AE agent must be added separately according to the desired amount of air.
Therefore, there were restrictions on its use. Therefore, the present inventors conducted intensive studies to solve these drawbacks of the conventional technology, and found an AE agent that is compatible with polycarboxylic acid admixtures, and when it is added, it has the performance of an AE type water reducing agent. death,
They also found that the operability during blending is improved, and have completed the present invention. (Means for Solving the Problems) Thus, according to the present invention, olefins - α, β
- A cement admixture composition is provided, which is characterized in that a polyoxyethylene alkyl sulfate ester salt or an alkyl sulfate ester salt is blended into an unsaturated dicarboxylate copolymer-based cement admixture. The copolymer-based admixture used in the present invention is a copolymer composed of an α,β-unsaturated dicarboxylic acid and an olefin, or a salt thereof. The composition of such a copolymer can be selected as appropriate, but usually (a)
It consists of 40 to 85 mol% of α,β-unsaturated dicarboxylic acid, preferably 45 to 80 mol%, and (b) olefin 60 to 15 mol%, preferably 55 to 20 mol%, and has a number average molecular weight of Usually 300-20000, preferably 1000-10000. Here, the number average molecular weight refers to high performance liquid chromatography (tetrahydrofuran solvent, measurement temperature 40°C).
It means the polystyrene equivalent measured by. Specific examples of the component (a) constituting the copolymer include maleic acid, itaconic acid, citraconic acid, anhydrides thereof, and maleic anhydride is particularly industrially advantageous. On the other hand, specific examples of the component (b) include ethylene, propylene, isobutylene, butene-1, butene-2, pentene-1, pentene-2,2-methylbutene-1,2-methylbutene-2,4-methyl Chain olefins such as pentene-1 and hexene-1, cyclobutene, cyclopentene,
Examples include cycloolefins such as cyclohexene, cycloheptene, cyclooctene, cyclopentadiene, dicyclopentadiene, 2-ethyl-5-norbornene, 2-cyano-5-norbornene, and 2-acetyl-5-norbornene, among which C Chain olefins having ₄ to ₆ carbon atoms and cycloolefins having ₄ to ₆ carbon atoms are preferred. Furthermore, vinyl monomers such as acrylic acid, vinyl acetate, methyl methacrylate, methyl vinyl ether, acrylonitrile, and ethylene sulfonic acid may be copolymerized within a range that does not essentially impair the effects of the present invention. A part of the carboxyl group and/or acid anhydride group in the copolymer may be esterified or amidated before use. If the produced copolymer itself is water-soluble, it can be used as is, but usually some or all of the carboxyl groups and/or acid anhydride groups present in the copolymer are monovalent or It is used by converting it into a salt with polyvalent cations to increase its water-solubilizing ability. Specific examples of such salts include salts of alkali metals or alkaline earth metals such as sodium, potassium, magnesium, calcium, barium, etc., ammonium salts, amine salts such as trimethylamine, triethylamine, triethanolamine, etc., and salts of these salts. Composite salts are exemplified, and alkali metal salts are particularly preferred from the viewpoints of economy, safety, and dispersion. The AE agent (admixture that provides air entrainment) used in the present invention is an alkyl sulfate salt type or a polyoxyethylene alkyl sulfate salt type, and such AE agent is represented by the following general formula (). R—O—(—CH ₂ —CH ₂ —O)— _o SO ₃ Specific examples of R include, for example, octyl group,
Examples include nonyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, etc., and those having 8 to 18 carbon atoms are usually used.
In addition to 0, n indicating the amount of ethylene oxide added is usually a positive number of 2 or less, and examples of X include monovalent cations such as sodium ions and potassium ions. When the number of carbon atoms in R is too large or too small, the compatibility tends to be poor, and the same tendency occurs when n is too large. Various substances have been known as AE agents, but in the present invention, it is essential to use the specific AE agents mentioned above. , polyoxypropylene alkyl sulfate salts, high acid value resin acid salts, etc., cannot be used because of their poor compatibility with polycarboxylic acid admixtures. The blending ratio of the AE agent can be selected as appropriate depending on the desired amount of air, the type of cement or aggregate, the blending, etc.
Usually, the amount is 0.1 to 5% by weight based on the solid content of the polycarboxylic acid admixture. The form of use of the admixture composition obtained in the present invention is not particularly limited, and it can be used in either an aqueous solution form or a solid form such as powder, and can be used in combination with other cement admixtures as necessary. You can also do it. Examples of cement admixtures that can be used in combination include conventional cement dispersants, cement wetting and dispersing agents, swelling agents, waterproofing agents, strength enhancers, hardening accelerators, coagulation accelerators, and coagulation retarders. The amount of the cement admixture composition of the present invention may be appropriately selected depending on the required performance, but it is usually used in a proportion of 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight, based on the solid content of cement. be done.
As the amount used decreases, the workability improvement effect decreases. Furthermore, the timing of addition to the cement mixture can be selected as appropriate depending on the intended use. Specific methods include, for example, mixing it with cement in advance, adding it at the same time when mixing cement mixtures such as concrete, adding it after adding water or other admixtures and starting stirring, and adding it in advance. An example is a method in which the additive is added at appropriate intervals after the product is kneaded. The type of cement to which the cement admixture composition of the present invention can be applied is not particularly limited, and specific examples include ordinary Portland cement, early strength Portland cement, alumina cent, moderate heat Portland cement, alumina cement, fly ash cement, Examples include blast furnace cement, silica cement, slag cement, and various mixed cements. (Effects of the Invention) Thus, according to the present invention, a cement admixture composition is obtained which imparts air entrainment properties in addition to dispersion fluidity and slump retention properties of cement, and such a composition is particularly useful as an AE type water reducer. It is. (Example) The present invention will be described in more detail with reference to Examples below. Note that parts and percentages in Examples and Reference Examples are based on weight unless otherwise specified. Reference Example 1 1 A mixture of 98 parts of maleic anhydride, 110 parts of the _C5 olefin mixture shown in Table 1, 4 parts of benzoyl peroxide, and 400 parts of benzene was heated at 70 to 75°C under a nitrogen atmosphere in an autoclave. After the polymerization reaction was completed, the precipitated copolymer was separately collected and dried to obtain a C ₅ olefin-maleic anhydride copolymer. Table 1 iso-pentane approx. 16% n-pentane approx. 15% 2-methylbutene-1 approx. 42% pentene-1 approx. 27% Isoprene 0.1% or less Example 1 30% of the sodium salt of the copolymer obtained in Reference Example 1 % aqueous solution and 6% aqueous solution of various AE agents in equal amounts,
The compatibility was evaluated by observing the state immediately after mixing and after being left at 20°C for 30 days. The evaluation was ○ if they were compatible, and × if there was layer separation or precipitation of insoluble matter. The results are shown in Table 2. From the results in Table 2, it can be seen that only alkyl sulfate salts and polyoxyethylene sulfate salts exhibit good compatibility.

【table】

[Table] Example 2 100 parts of a 30% aqueous solution of the sodium salt of the copolymer obtained in Reference Example 1 and 7.1 parts of a 6% aqueous solution of an alkyl sulfate sodium salt (R=C ₁₀ - ₁₂ ) were mixed. The performance of the homogeneous aqueous solution as an AE type water reducing agent was evaluated as follows. The blending formula is as shown in Table 3, and the materials used are Asano ordinary Portland cement, fine aggregate (sand from Oigawa, specific gravity = 2.62, FM = 2.78), coarse aggregate (crushed stone from Ome, specific gravity = 2.65, F=6.60),
The mixture was kneaded for 3 minutes using a 50° force mixer. JIS A1101 and JIS A1128 are used to measure the slump and air of concrete that has not hardened yet.
Accordingly, the freeze-thaw test was conducted in accordance with JIS A6204 Annex 2, and the relative dynamic elastic modulus was measured. The results are shown in Table 4.

[Table] * Based on cement solid content Example 3 Same as Example 1 except that polyoxyethylene alkyl sulfate sodium salt (R = C ₁₈ to ₁₁ , n = 1.5) was used instead of alkyl sulfate sodium salt. I did the test. Comparative Example 1 A test was conducted in the same manner as in Example 2, except that the sodium salt of the copolymer obtained in Reference Example 1 was used alone and the formulation was changed as shown in Table 3. The results are shown in Table 4.

[Table] From the results in Table 4, it can be seen that in the case of the present invention, the relative dynamic elastic modulus is 95% or more, and AE concrete with extremely excellent freeze-thaw resistance can be obtained.

Claims (1)

[Claims] 1. A cement admixture composition comprising a cement admixture based on an olefin-α,β-unsaturated dicarboxylate copolymer and a polyoxyethylene alkyl sulfate salt or an alkyl sulfate salt.