JPH08295546A - Air entraining agent for fly ash-containing cement composition - Google Patents

Abstract

PURPOSE: To exhibit sufficient air entraining property and to prevent the lowering of the quantity of air to be entrained with the lapse of time or in a process such as transportation, pile-driving or compaction by composing an air entraining agent for cement composition of a specific amine or an amide derivative and an anionic surfactant. CONSTITUTION: This air entraining agent for cement composition consists of 99-1 pts.wt. compound (A) selected from the amine or amine derivative expressed by formulas I, II and III (each of R1 -R3 is an 8-22C alkyl or alkenyl group, each of A1 O, A2 O and A3 O is an oxyalkylene group, each of (m) and (n) is integer of >=1 and m+n=2-50, each of (a), (b) and (c) is integer of >=1 and a+b+c=3-50 and each of (p) and (q) is integer of >=1 and p+q=2-50) and 1-99 pts.wt. compound (B) selected from at least one kind of the anionic surfactant expressed by the formula R4 COOM (R<4> is an 8-30C alkyl or alkenyl group, M is an alkali (earth) metal or an alkanol amine).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an air entraining agent for cement compositions, especially for concrete and mortar.

[0002]

2. Description of the Related Art Generally, about 3 to 6 is usually added to concrete.
An air entraining agent (AE agent) is used to mix in% air. The main component of this air entraining agent is a surfactant, which introduces independent fine air bubbles into the concrete. As a result, due to the ball bearing effect of air bubbles in uncured concrete, the flowability is improved and workability is improved, and after curing, the expansion pressure when water in the capillary gap is condensed is relaxed, The resistance to the freeze-thaw action of the cured product is significantly improved.

Conventionally, an air entraining agent (AE agent) which is mainly a surfactant for entraining air in the cement composition.
Is used. Examples of such AE agents include polyoxyethylene alkyl ether sulfates or salts thereof, polyoxyethylene alkylphenyl ether sulfates or salts thereof, polyoxyethylene alkyl ether phosphates or salts thereof, polyoxyethylene alkylphenyl ether phosphorus. Anionic surfactants such as acid ester or its salt, alkylbenzene sulfonic acid or its salt, resin acid or its salt, fatty acid or its salt, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sorbitan ole Nonionic surfactants such as ates are known. Further, as a typical example, there is vinsol resin which is an aqueous solution obtained by adding an alkali to rosin obtained by solvent extraction purification of pine resin.

However, when air is entrained in a cement composition using a conventional air entraining agent, there are the following problems. One is that the air amount stability, that is, the entrained air amount decreases with time. Especially when using ready-mixed concrete, the air bubbles carried during production are
It will be lost in each process such as driving and compaction, and it will not be possible to obtain concrete of the target quality.
Further, due to the recent demand for highly durable and high-quality concrete, it is necessary to improve the quality of the air bubbles entrained along with the stability of the air amount. That is, it is to uniformly entrain fine bubbles to improve the freeze-thaw resistance of concrete. In view of such a current situation, there has been a strong demand for an air entraining agent that solves the above problems.

[0005]

An object of the present invention is to carry fine air bubbles having sufficient air entrainment in order to stably produce a cement composition having high freeze-thaw resistance and high quality. Another object of the present invention is to provide an air entraining agent for a cement composition, which prevents a decrease in the amount of entrained air in processes such as passage of time, transportation, driving, compaction and the like.

[0006]

As a result of intensive studies to solve the above problems, the present inventors have found that a composition comprising a certain amine or amide derivative and an anionic surfactant is a cement composition. Therefore, the present invention was found to be a composition effective for exerting an excellent air entrainment effect, stably maintaining a predetermined entrainment air amount, and improving freeze-thaw resistance, and thus reached the present invention. That is, the present invention is characterized in that the air entraining agent for cement composition is composed of the following compound A and compound B. (A) A compound A selected from at least one amine or amide derivative represented by the following general formula (1), general formula (2) or general formula (3).

[0007]

Embedded image _{(R 1, R 2, R} 3: an alkyl group or alkenyl group A ₁ O 8 to 22 carbon _{atoms, A 2 O, A 3 O} : oxyalkylene group m having a carbon number of 2 or 3, n: 1 or more respective M + n = 2 to 50 a, b, c: integers of 1 or more, a + b + c = 3
˜50 p, q: each an integer of 1 or more, p + q = 2 to 50) (B) Compound B selected from at least one anionic surfactant represented by the general formula (4) of the following chemical formula 4.

[0008]

Embedded image R ₄ COOM (4) (R _{4 is} an alkyl or alkenyl group having 8 to 30 carbon atoms M: alkali metal, alkaline earth metal or alkanolamine)

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The amine or amide derivative represented by the compound A of the present invention is obtained by adding an alkylene oxide to an amine or amide having an alkyl group or an alkenyl group by a conventional method. The number of moles of ethylene or / and propylene oxide added is
In the general formula (1), m + n = 2 to 50 mol, preferably 5
˜30 mol, a + b + c = 3 to 50 mol in the general formula (2), preferably 5 to 30 mol, p + q in the general formula (3).
= 2 to 50 mol, preferably 5 to 30 mol. In each of the general formulas (1), (2), and (3),
The addition form of alkylene oxide is an ethylene oxide adduct (EO), a block or random adduct of ethylene oxide (EO) / propylene oxide (PO). Examples of the alkyl group and alkenyl group in the amine or amide derivative include oleyl, stearyl, lauryl, coconut aliphatic (coconut alkyl), beef tallow aliphatic and soybean aliphatic.

The anionic surfactant represented by the compound B of the present invention is obtained by neutralizing a linear or branched fatty acid having an alkyl group, an alkenyl group and a carboxyl group having 8 to 30 carbon atoms. Is. The fatty acids mentioned here include the following. Caprylic acid, capric acid, lauric acid, stearic acid, oleic acid, linoleic acid, myristic acid, parimitic acid, coconut oil fatty acid, tall oil fatty acid, rapeseed fatty acid and other natural fats and oils, isostearic acid But you can
Particularly preferred are oleic acid, lauric acid, stearic acid, linoleic acid, coconut oil fatty acid, tall oil fatty acid and the like. By neutralizing these fatty acids with an aqueous solution of sodium hydroxide, potassium hydroxide, monoethanolamine, diethanolamine, triethanolamine or the like, the anion activator represented by the compound B of the present invention can be obtained.

The compound A and the compound B thus obtained are 1 to 99 parts by weight, preferably 10 to 90 parts by weight of the compound A.
Parts by weight, 99-1 parts by weight of compound B, preferably 90-
An air entraining agent having a desired effect can be obtained by blending it in a mixing ratio of 10 parts by weight. Even if the compound A and the compound B of the present invention are used alone, good quality air bubbles are not entrained and the stability of the air amount is lowered, so that the intended effect is not exhibited.

The air entraining agent in the present invention exerts an effect on the cement composition, but any known cement may be used, for example, Portland cement or early strength / super early strength / moderate strength. Heat / jet cement, fly ash cement, blast furnace cement, silica cement, alumina cement, etc., but it is desirable to use them for cement compositions other than fly ash cement. Further, low heat-generating Portland cement, high fluidity concrete cement, and high strength concrete cement, which have recently been used as high performance concrete cement, may be used.

The required amount of the air entraining agent of the present invention is such that when the amount of introduced air is in the range of about 3% to 7%, the effective amount of the air entraining agent is as a general added amount, and On the other hand, 0.0001 to 0.1% by weight, preferably 0.1.
It is in the range of 0005 to 0.05% by weight. In the present invention, the method of adding the air entraining agent is the same as in the case of a general air entraining agent, and is added at the time of kneading the cement composition, or by diluting the mixture in advance in kneading water, or adding the cement composition. It may be added after kneading and then kneaded again uniformly. Further, the two components of the compound A and the compound B of the present invention may be added separately at a predetermined ratio.

The air entraining agent of the present invention is an admixture conventionally used for improving the performance and properties of concrete, for example, a high performance water reducing agent, an AE water reducing agent, a high performance AE water reducing agent, a superplasticizer, It can be used in combination with various admixtures (agents) such as a curing accelerator, a curing retarder, a waterproofing agent, a rust preventive, a shrinkage reducing agent, an expanding material (agent) and a thickener.

[0015]

According to the air entraining agent of the present invention, a cement composition containing a desired amount of air can be stably and continuously produced. In addition, the produced cement composition has no reduction in entrained air at each stage of transportation, unloading, driving, and compaction, and fine bubbles remain sufficiently after curing, strength development, freeze-thaw resistance, etc. The durability of is also sufficient.

[0016]

EXAMPLES The air entraining agent for cement composition according to the present invention will be described below with reference to Examples and Comparative Examples. (1) Formulation example of air entraining agent Table 1 shows the contents and the component ratios of the compound A and the compound B used in the air entraining agent of the examples of the present invention. Table 1 also shows the component ratios of the compounds used as comparative examples.

[0017]

[Table 1]Table 1: Composition of air entrainment agent Airborne agent types Compound A Alkylene oxide mixture Symbol General formula Alkyl group type Type Number of moles added Compound B A / B A (1) Oleyl EO m + n = 10 Oleic acid Na 1/2 B (1) Oleyl EO m + n = 20 Oleic acid Na 1/1 C (2) Beef tallow EO a + b + c = 15 Oleic acid Na 2/1 D (3) Oleyl EO p + q = 5 Oleic acid Na 1/3 E (1) Palm EO / PO * m + n = 16 Oleic acid Na 1/2 F (2) Soybean EO a + b + c = 3 Na stearate 1/3 G (1) Oleyl EO m + n = 15 Tall oil fatty acid Na 1/1 H (3) Stearyl EO p + q = 10 Na 1/2 laurate I NP10 Na oleate / 1 J (1) oleyl EO m + n = 15 gum rosin K salt 1/1 K-oleic acid Na- L (1) Oleyl EO m + n = 10 − − NP10: Nonylphenol with 10 mol of ethylene oxide added (used in place of amine and amide derivative of compound A) *: 8 mol of EO, 8 mol of PO8 block polymer (2) Materials used Table 2 shows the materials used.

[0018]

[Table 2] Table 2: Materials used Cement (C) Normal Portland cement made by Onoda Cement Specific gravity 3.16 Fine aggregate (S) Fujikawa river sand Specific gravity 2.60 FM2.71 Coarse aggregate (G) Kisarazu crushed stone Specific gravity 2.65 FM6.54 Water (W) Tap water

(3) Test method Concrete production and evaluation were carried out according to the following rules. Mixing of concrete: JIS-A1138 Slump: JIS-A1101 Air amount: JIS-A1128 Air bubble spacing coefficient: ASTM-C457 Compressive strength: JIS-A1132 and 1108

(4) Manufacture of concrete Using a 200-liter forced mixer, the target air amount of the kneaded concrete was 5%, the target slump was 8 cm, and the materials shown in Tables 1 and 2 were used. It was manufactured using the formulation shown in Table 3. The amount of the air entraining agent was adjusted so that the amount of the entrained air was 5%, and the air entraining agent was dissolved in kneading water in advance and added to the concrete for production of concrete. With respect to the obtained concrete, the amount of air, slump, the amount of air after 30 minutes and 60 minutes after kneading, the slump, the compressive strength of 7 days and 28 days of age, and the cell spacing coefficient of the cured specimen were measured.

[0021]

[Table 3] Table 3: Formulation conditions W / C S / a formulation (kg / m ³ ) (%) (%) C W S G 61.0 45 300 300 183 776 995 S / a = [volume of fine aggregate / (Volume of fine aggregate + volume of coarse aggregate)] x 100 (%)

Examples 1 to 8 Compounds A to M were used according to the formulations shown in Table 4 and Example 1 was used.
-8, the slump, the amount of air, the cell spacing coefficient, and the compressive strength of the concretes obtained in Comparative Examples 1 to 4 were measured. These results are summarized in Table 4.

[0023]

[Table 4]Table 4: Slump (cm) Air volume (%) Compressive strength Air entrainment agent Immediately 30 minutes 60 minutes Immediately 30 minutes 60 minutes Bubble interval (kgf / cm²) Type Usage * After after After coefficient (μm) 7 days 28 days Example No. 1 A 0.0007 8.0 7.2 6.2 5.0 4.5 4.1 189 204 299 2 B 0.0010 8.2 7.1 6.0 5.2 4.5 4.0 190 198 288 3 C 0.0012 7.9 6.9 6.0 4.9 4.4 3.9 179 210 290 4 D 0.0009 8.1 7.3 6.1 5.2 4.6 4.0 201 189 279 5 E 0.0011 8.0 7.1 5.9 5.3 4.7 4.2 192 201 295 6 F 0.0010 7.9 7.0 6.0 5.0 4.4 4.0 190 210 302 7 G 0.0009 8.4 7.5 6.8 4.8 4.2 3.8 178 199 283 8 H 0.0012 8.1 7.2 6.4 5.1 4.3 3.9 195 205 301 Comparative Example No. 1 I 0.0040 8.1 5.2 3.6 4.8 3.2 2.4 320 179 270 2 J 0.0080 7.8 4.7 3.1 5.3 3.4 2.6 367 175 268 3 K 0.0097 8.4 5.3 3.5 5.0 3.5 2.4 411 181 271 4 L 0.0085 8.0 5.0 3.3 5.1 3.6 2.5 386 170 265 *: The amount used is% by weight of the active ingredient of the air entraining agent with respect to the cement.

The composition of the present invention, as shown in the examples in Table 4, has a low loading for entraining about 5% air,
Not only is it excellent in air entrainment, but it is also good in holding air volume for up to 60 minutes. The bubble spacing coefficient, which is an index of freeze-thaw resistance, was 300 to 400 μm in Comparative Example.
In contrast, the product of the present invention is as small as 200 μm or less, showing that fine bubbles are entrained, and it is suggested that the product of the present invention has sufficient freeze-thaw resistance. In addition, the product of the present invention also exhibits excellent effects on slump retention and compressive strength.

Claims (1)

[Claims] 1. A compound A selected from at least one amine or amide derivative represented by the following general formula (1), general formula (2) or general formula (3): ] _{(R 1, R 2, R} 3: an alkyl group or alkenyl group A ₁ O 8 to 22 carbon _{atoms, A 2 O, A 3 O} : oxyalkylene group m having a carbon number of 2 or 3, n: 1 or more respective M + n = 2 to 50 a, b, c: integers of 1 or more, a + b + c = 3
˜50 p, q: each an integer of 1 or more, p + q = 2 to 50) (B) Compound B selected from at least one anionic surfactant represented by the following general formula (4) (4) R ₄ COOM (4) (R _{4 is} an alkyl or alkenyl group having 8 to 30 carbon atoms, M is an alkali metal, alkaline earth metal or alkanolamine), and is air-entrained for a cement composition. Agent.