JPH025699B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a novel admixture composition for hydraulic cement, and more specifically, it has air-entraining properties and has excellent performance as a dispersant, water-reducing agent, fluidizing agent, etc. This invention relates to a novel admixture composition for hydraulic cement. (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, aromatic compound sulfonate-based admixtures have been known as typical examples of such admixtures, and olefin-based admixtures have been used to improve their water-reducing performance.
α,β-unsaturated dicarboxylic acid copolymer system (hereinafter referred to as
A method of using an admixture (sometimes simply called polycarboxylic acid) is also known (for example,
No. 55-51863, Japanese Patent Publication No. 58-213663, etc.). (Problems to be Solved by the Invention) However, since aromatic compound sulfonate-based admixtures generally have antifoaming properties, and polycarboxylic acid-based admixtures are generally non-air-entraining, Combination systems are not necessarily suitable for formulation systems that require air entrainment, and may be difficult to adjust to the desired amount of air.
If AE agents (admixtures that impart air entrainment properties) are added after they have been blended, there is a problem in that the amount of air entrainment decreases, impairing durability. Therefore, the present inventors conducted intensive studies to solve these drawbacks of the conventional technology, and as a result, discovered an AE agent that is compatible with both aromatic compound sulfonate-based admixtures and polycarboxylic acid-based admixtures, and further developed the AE agent. The inventors have discovered that a cured cement product with excellent durability can be obtained by blending the above, and have completed the present invention. (Means for Solving the Problems) Thus, according to the present invention, (a) an aromatic compound sulfonate cement admixture and (b) an olefin-based cement admixture
A cement admixture composition is provided, which comprises (c) a polyoxyethylene alkyl sulfate salt or an alkyl sulfate salt added to a mixture of an α,β-unsaturated dicarboxylic acid copolymer cement admixture. (a) used as the first component in the present invention
An aromatic compound sulfonate admixture is a water-soluble compound having an aromatic compound sulfonate or an aromatic compound sulfonate unit in the molecule, and is effective as a dispersant, water reducing agent, or fluidizing agent. Examples include monocyclic or polycyclic fused formulas such as benzene, naphthalene, fluorene, anthracene, phenanthrene, pyrene, naphthacene, pentacene, coronene, hexacene, heptacene, octacene, nonacene, decacene, undecacene, dodecacene, acenaphthene, etc. Aromatic hydrocarbons and derivatives thereof having one or two substituents such as -NH ₂ , -OH, -COOH, alkyl groups of 1 to 2 carbons, or aromatization such as creosote oil and petroleum decomposition products Water-soluble salts of sulfonated products of monocyclic or polycyclic condensed aromatic compounds such as hydrogen mixtures with aliphatic aldehydes such as formaldehyde (for example, Japanese Patent Publications No. 35-9443, No. 41-11737,
No. 40-26249, No. 47-39208, JP-A-49-
No. 104919, No. 48-69824, No. 50-89423, No. 50
-29644), or a water-soluble salt of the co-condensed product obtained by condensing the sulfonated product with an aliphatic aldehyde and substituting a part of the sulfonated product with the above aromatic compound that does not contain a sulfonic acid group (for example, No. 58120 (Sho 50-58120), or similarly melamine,
Water-soluble salts of co-condensed products by substituting a part of the above sulfonated compounds with urea etc., or water-soluble salts of sulfonated polycyclic condensed aromatic compounds having three or more aromatic rings among the above aromatic compounds, etc. can be mentioned. These water-soluble salts include alkali metal salts,
It is used as an alkaline earth metal salt or a lower amine salt such as methylamine or morpholine. (b) used as the second component in the present invention
The copolymer-based admixture 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) 40 to 85 mol% of α,β-unsaturated dicarboxylic acid, preferably 45 to 80 mol%, and (b) α,β-unsaturated dicarboxylic acid.
It consists of 60 to 15 mol% of olefin, preferably 55 to 20 mol%, and the number average molecular weight is usually 300 to 20,000, preferably 1,000 to 10,000. 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 _4-6 chain olefins and _C4 - _C6 cycloolefins 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. Examples include complex salts, among which alkali metal salts are preferred from the viewpoint of economy, safety, and dispersibility. The ratio of the first component to the second component (based on weight) can be selected as appropriate, but is usually 95 to 5:5.
95, preferably 80-20:20-80, particularly preferably 70-30:30-70. (c) used as the third component in the present invention
The AE agent (admixture that provides air entrainment) is an alkyl sulfate salt or polyoxyethylene alkyl sulfate salt, and such AE agent
The agent is represented by the following general formula (). R-O--( _CH2 - _CH2 -O-) _{o SO3X}
...() (In the formula, R is a long-chain alkyl group, n is 0 or a positive number, and X represents a monovalent cation.) Specific examples of the above R include, for example, an 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 they have poor compatibility with the mixture of components (a) and (b). 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.
It is usually 0.1 to 5% by weight on a solids basis based on the total of the first and second components. 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. can also be done. 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 2% by weight, preferably 0.02 to 1.0% 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 appropriately selected 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 types of cement to which the cement admixture composition of the present invention can be applied are not particularly limited, and specific examples thereof include ordinary Portland cement, early strength Portland cement, moderate heat Portland cement, alumina cement, fly-ash cement, blast-furnace cement, Examples include silica cement, slag cement, and various mixed cements. (Effects of the Invention) Thus, according to the present invention, a cement admixture composition can be obtained which imparts air entrainment properties in addition to dispersion fluidity and slump retention properties of cement, and such a composition can be prepared by adding a dispersant, a water reducing agent, a fluidizing agent, etc. It is useful as a curing agent. (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 1 100 parts of β-naphthalene sulfonic acid and 20 parts of water
While maintaining the temperature at 85°C, 42 parts of 37% formalin was added dropwise over 3 hours. After formalin addition, further
The reaction was stirred at 100°C for 7 hours. During this time,
45 parts of water was added dropwise. After liming the condensation reaction product, sodation was further performed to obtain an aqueous solution of the sodium salt of naphthalene sulfonic acid formalin condensate (2) containing 8.5% of mononuclear substance. Reference Example 2 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 for 8 hours in an autoclave under a nitrogen atmosphere. The mixture was heated and stirred to react. After the polymerization reaction was completed, the precipitated copolymer was separately collected and dried to obtain a _C5 olefin-maleic anhydride copolymer. Table 1 iso-pentane approx. 16% n-pentane approx. 15% 2-methylbutene-1 approx. 42% pentene-1 approx. 27% Isobrene 0.1% or less Example 1 Water-soluble salt () obtained in Reference Example 1 70% and Reference example 2
Mix equal amounts of a 30% aqueous solution of a 30% mixture of the sodium salt () of the copolymer obtained in step 1 and a 6% aqueous solution of various AE agents, and observe the state immediately after mixing and after leaving it at 20°C for 30 days to determine whether it is compatible. Solubility was evaluated. 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. Example 2 Example 1 except that the usage ratio of water-soluble salt () and water-soluble salt () was changed to 30% for the former and 70% for the latter.
A compatibility test was conducted in the same manner as above. As a result, almost the same results as in Example 1 were obtained.

[Table] Example 3 Cement mortar with the following composition was prepared and JIS-
A mortar test was conducted according to R-5201. The amount of admixture added was adjusted so that the target flow was 230±5 mm. Note that the amount of air entrainment was measured according to JIS-A-1116. The mortar temperature was 20±2°C. Cement: Asano ordinary Portland cement Sand: River sand from Oigawa Mixed cement: 600 parts Sand: 1200 parts Water: 210 parts (Total amount including water in the admixture below) Cement admixture: As shown in Table 3 Cement/sand ratio = 1/2 cement/water ratio = 1/0.35

[Table] *2 Comparison with cement, non-volatile content standard example 4 The following concrete formulation was used to evaluate the formulation for general concrete. Concrete blended cement: 300Kg/m ² Asano ordinary Portland cement coarse aggregate: 1012Kg/m ² Ome crushed stone (maximum particle size 25mm) Fine aggregate: 815Kg/m ² Oigawa sand water: 1660Kg/m ² (with admixture Total amount) Hydraulic cement admixture: As shown in Table 4 Water/cement ratio: 55.3% Fine aggregate ratio: 44.6% Slump and air volume measurements of unhardened concrete are based on JIS A1101 and JIS A1128, respectively, and freeze-thaw resistance Sex test measurements are ASTM C666A
I followed the section. The results are shown in Table 4.

[Table] *2 Cement, non-volatile content standards From Table 4, it can be seen that even when used in concrete, it has good dispersibility and air is entrained. Also AE
It shows the same durability as when the agent is used alone.

Claims (1)

[Claims] 1 (a) Aromatic compound sulfonate-based cement admixture, (b) Olefin-α,β-unsaturated dicarboxylic acid copolymer-based cement admixture, and (c) polyoxyethylene alkyl sulfate ester salt or alkyl sulfate ester salt A cement admixture composition comprising: