JPH08295545A - 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 incorporating a specific anionic surfactant and an amine derivative in a fly ash-containing cement composition. CONSTITUTION: This air entraining agent for the fly ash-containing cement composition consists of (A) 99-1 pts.wt. at least one kind of an anionic surfactant expressed by the formula R<1> COOM (R<1> is an 8-30C alkyl or alkenyl group, M is an alkali (earth) metal or an alkanol amine) and (B) 1-99 pts.wt. at least one kind of amine derivative expressed by the formula (R<2> is an 8-22C alkyl or alkenyl group, each of (m) and (n) is integer of >=1 and m+n=2-5). The air entraining agent is added and used in an amount of 0.001-0.1wt.% based on the total quantity of a binder in the cement and the fly ash.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air entraining agent for fly ash-containing cement composition. Here, the fly ash-containing cement composition means a hydraulic material such as mortar and concrete that is kneaded with water and an aggregate using cement containing fly ash as a hydraulic binding material.

[0002]

2. Description of the Related Art A cement composition containing fly ash is
Since the pozzolanic reaction (silicic acid in fly ash reacts with calcium hydroxide) to form strong crystals, the long-term strength of the hardened product is superior to that of general Portland cement, and calcium oxide, the main component of cement, is used. The heat generated by the hydration reaction decreases, the drying shrinkage decreases, and the fly ash particles are spherical, which increases the fluidity of fresh concrete and improves the workability. In addition, because of its low price, it is widely used as a building material, including mass concrete for dams.

Further, in recent years, as environmental and resource protection is being called for on a global scale, the problem of processing fly ash, which is a by-product of thermal power generation, is becoming serious. At present, waste disposal by landfill is the mainstream, but on the other hand, it is considered promising to use fly ash cement by partially adding fly ash to the cement as an effective use.

Generally, about 3-6% in concrete
Air entraining agent (AE
Agent) is used. The main component of the AE agent is a surfactant, which introduces independent fine bubbles into the concrete. As a result, in uncured concrete, the fluidity is improved and the workability is improved due to the ball bearing effect of air bubbles. Further, since the expansion pressure when water in the capillary gap is condensed after the curing is relaxed, the resistance of the cured product to the freeze-thaw action is significantly improved.

However, in the concrete using fly ash cement (fly ash concrete), there is a problem that it is difficult to control the amount of mixed air.
For example, with the usual amount of AE agent added, the amount of air entrained is significantly smaller than that of general concrete,
The fact is that the amount of air decreases over time.
It is said that the cause is that the unburned carbon contained in the fly ash adsorbs the AE agent, but the unburned carbon amount in the fly ash tends to increase due to the tightening of NOx regulations at thermal power plants. Therefore, in order to use these fly ash as a cement admixture,
The development of better AE agents was essential.

Also, from the viewpoint of quality control, the amount of unburned carbon in the fly ash varies depending on the operating conditions produced by the fly ash. Therefore, in order to keep the entrained air amount within the allowable range, the amount of unburned carbon must be adjusted in advance. Had to be determined by a methylene blue adsorption amount test or the like to determine the addition amount of the AE agent, and the work was very complicated and there was a real problem.

However, conventionally, the same AE agent as that which is usually used for a Portland cement-containing cement composition has been used to entrain air in the fly ash-containing cement composition. 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, and nonionic such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sorbitan oleate, etc. Surfactants are known. However, when these AE agents are used in a cement composition containing fly ash, there has been a problem that the addition amount increases and the air amount decreases as described above.

Further, as a combined system of an anionic surfactant and a nonionic surfactant, a resin acid salt and an amine derivative are used in JP-A-61-6020 to improve air entrainment and air amount stability. An air entrainment agent has been proposed, but when it is applied to a fly ash-containing cement composition, its effect is significantly reduced.

On the other hand, in order to solve the above problems, in recent years, as an air entraining agent for fly ash-containing cement compositions,
JP-A-58-55353 (polyoxyethylene sorbitan oleate), JP-A-59-174555 (polyoxyethylene sorbitol fatty acid ester), JP-A-1-157442 (polyoxyethylene polyhydric alcohol) Combined use of a fatty acid ester or a fatty acid ester of polyethylene glycol and a fatty acid salt), JP-A-2-6356 (ester-based nonionic surfactant starting from a special ether sulfate anionic surfactant having an aromatic ring and a polyhydric alcohol) JP-A-2-180739 (combination of fatty acid soap-based anionic surfactant and ester-based nonionic surfactant starting from polyhydric alcohol) has been devised. However, these AE agents lack stable and sufficient air entrainment and air amount retention with respect to variations in fly ash quality (amount of unburned carbon, etc.). Therefore, there has been a strong demand for an air entraining agent that suppresses adsorptivity to fly ash and entrains high-quality air bubbles to stably produce a fly ash-containing cement composition having high freeze-thaw resistance and high quality.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an air entraining agent for unburned carbon in fly ash in order to stably produce a fly ash-containing cement composition having high freeze-thaw resistance and good quality. Fly ash that suppresses adsorption and has sufficient air entrainment without being affected by fluctuations in the amount of unburned carbon, and at the same time prevents a decrease in the amount of entrained air during processes such as aging, transportation, driving, and compaction. An object is to provide an air entraining agent for a cement composition containing the same.

[0011]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors to solve the above problems, a composition comprising a certain anionic surfactant and an amine derivative was found to be a fly ash-containing cement composition. The present invention has been accomplished by discovering that the composition is effective for exerting an excellent air entrainment effect on an object and maintaining a predetermined entrained air amount stably. That is, the present invention is characterized in that the air entraining agent for fly ash-containing cement composition comprises the following components (A) and (B). (A) at least one kind of anionic surfactant represented by the following general formula (1): 99 to 1 part by weight,

[0012]

Embedded image R ¹ —COOM (1) (R ¹ : an alkyl group or an alkenyl group having 8 to 30 carbon atoms, M: an alkali metal, an alkaline earth metal or an alkanolamine) (B) the following general formula: At least one kind of the amine derivative represented by (2): 1 to 99 parts by weight

[0013]

[Chemical 4] (R ^2: an alkyl group or an alkenyl group m of 8 to 22 carbon atoms, n: each an integer of 1 or more, m + n = 2~50)

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The component (A) of the present invention is an anionic surfactant represented by the general formula (1) shown below.

[0015]

Embedded image R ¹ —COOM (1) (R ^{1 is} an alkyl or alkenyl group having 8 to 30 carbon atoms M: alkali metal, alkaline earth metal or alkanolamine)

The anionic surfactant represented by the general formula (1) 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. It is what is done. Examples of the fatty acid as used herein include caprylic acid, capric acid, lauric acid, stearic acid, oleic acid, linoleic acid, myristic acid, palmitic acid, coconut oil fatty acid, tall oil fatty acid, rapeseed fatty acid, and other natural fats and oils; Examples thereof include isostearic acid, and particularly preferable examples include 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, etc., an anionic surfactant represented by the general formula (1) of the present invention can be obtained. To be The component (B) of the present invention is an ethylene oxide adduct of an amine represented by the following general formula (2).

[0018]

[Chemical 6] (R ^2: an alkyl group or an alkenyl group m of 8 to 22 carbon atoms, n: each an integer of 1 or more, m + n = 2~50)

The amine derivative represented by the general formula (2) is a primary amine having an alkyl group or an alkenyl group, such as oleylamine, stearylamine, laurylamine, coconut alkylamine, tallow alkylamine, soybean alkylamine, and the like. Obtained by adding ethylene oxide by a conventional method. The number of moles of ethylene oxide added (m + n) to the amine is suitably 2 to 50 moles, preferably 5 to 30 moles.

The thus obtained compounds of the general formula (1) and the general formula (2) are added in an amount of 99 to 1 parts by weight, preferably 90 to 10 parts by weight, of the compound of (2). 1
The air entraining agent having a desired effect can be obtained by blending it in a mixing ratio of ˜99 parts by weight, preferably 10 to 90 parts by weight. In addition, even if the compounds represented by the general formulas (1) and (2) of the present invention are used alone, the amount used as an air entraining agent is increased, and high quality air bubbles are not carried. Does not have the effect.

The required amount of the air entraining agent of the present invention is
Almost unaffected by the blending ratio of fly ash to various cements and the amount of unburned carbon in fly ash,
When the amount of introduced air is in the range of about 3% to 7%, the amount of air entraining agent is generally 0.0001 to 0.0001 to the total amount of binder, which is the total amount of cement and fly ash.
It is in the range of 0.1% by weight, preferably 0.0005 to 0.05% by weight.

The fly ash in the present invention is JIS
It also refers to fly ash specified in A6201 and fly ash that does not conform to those standards. In particular, the amount of unburned carbon is 5% or less in the above JIS,
The present invention is extremely excellent in that it exerts a sufficient effect even if the amount of unburned carbon exceeds 5%. In particular, the air entraining agent of the present invention is suitable for a cement composition using a fly ash cement containing 0.1 to 95% by weight, preferably 1 to 60% by weight of fly ash, and carbon of 0. When it is used as an air entraining agent for a cement composition using a fly ash containing 0.1 to 20% by weight, preferably 0.1 to 15% by weight, it exerts its action effect.

The cement in the present invention may be any cement known in the art, and examples thereof include Portland cement, early-strength / super-early-strength / moderate heat / jet cement, blast furnace cement, silica cement, alumina cement and the like. . In the present invention, the method of adding an air entraining agent is the same as in the case of a general air entraining agent, or added at the time of kneading the fly ash-containing cement composition,
It may be diluted in the kneading water in advance and added, or the fly ash-containing cement composition may be added after kneading and then kneaded again uniformly. Further, two components of the compounds represented by the general formula (1) and the general formula (2) of the present invention may be added separately at a predetermined ratio.

Further, the air entraining agent of the present invention is an admixture material 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 A.
E Water-reducing agent, fluidizing agent, hardening accelerator, hardening retarder, waterproofing agent, rust preventive, shrinkage reducing agent, expanding agent (material), can also be used in combination with various admixture materials such as thickeners .

[0025]

According to the air entraining agent of the present invention, the amount of unburned carbon remaining in the fly ash does not affect the amount of air entrained. Therefore, the content of fly ash containing a desired amount of air is included. The cement composition can be stably and continuously produced. Further, the fly ash-containing cement composition produced by adding the air entraining agent of the present invention has no decrease in entrained air at each stage of transportation, unloading, driving and compaction, and fine bubbles after curing. It sufficiently remains and has sufficient durability such as strength development and freeze-thaw resistance.

[0026]

EXAMPLES The air entraining agent for fly ash-containing cement composition according to the present invention will be described below with reference to Examples and Comparative Examples. (1) Fly ash used The fly ash used was two kinds (and) of different unburned carbon amounts as shown in Table 1.

[0027]

[Table 1] Table 1: Characteristics of fly ash used Loss on ignition (%) MB adsorption amount (mg / g) Specific gravity fly ash 1.3 0.28 2.12 Fly ash 8.4 0.85 2.17

(2) Formulation example of air entraining agent General formulas (1) and (2) in the air entraining agent of the present invention
Table 2 shows the component ratio (based on weight) of the compound (1). Table 2 also shows the component ratios of the compounds used as comparative examples.

[0029]

[Table 2] Table 2: Blending component of air entraining agent and mixing ratio Compound blending ratio compound compound Entraining agent Compound (1) Compound (2) (1) / (2) A Sodium oleate R1EO 5 2/1 B Sodium oleate R1EO5 1/2 C Sodium oleate R1EO10 3/1 D Sodium oleate R1EO10 2/1 E Sodium oleate R1EO15 3/1 F Sodium oleate R1EO15 1/1 G Sodium stearate R2EO15 1/1 H Toll Oil fatty acid sodium R3EO10 2/1 I sodium laurate R4EO10 3/1 J gum rosin potassium salt R1EO15 1/1 K sodium oleate NP10 1/1 L sodium oleate --- M-R1EO10- N Vinsol (Yamasou Chemical Co., Ltd. ) made) R1EO 5: oleylamine Ethylene oxide 5 mol addition product R1EO10: Oleylamine 10 mol ethylene oxide addition product R1EO15: Oleylamine 15 mol ethylene oxide addition product R2EO15: Beef tallow alkylamine ethylene oxide 15 mol addition product R3EO10: Soybean alkylamine 10 mol ethylene oxide addition product R4EO10: Coconut alkylamine 10 mol ethylene oxide addition product NP10: Nonylphenol ethylene oxide 10 mol addition product

(3) Materials used Table 3 shows the materials used.

[0031]

[Table 3] Table 3: Materials used Cement (C): Normal Portland cement made by Onoda Cement Specific gravity 3.16 Fine aggregate (S): Fujisawa produced river sand Specific gravity 2.60 FM2.71 Coarse aggregate (G): Kisarazu crushed stone Specific gravity 2.65 FM6 .54 Water (W): Tap water

(4) 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

(5) Manufacture of concrete For the 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 Table 1, Table 2 and Table 3 were used. Used and made using the formulation shown in Table 4 for each fly ash species. The air entrainment agent has an entrainment air volume of 5%.
The amount of addition was adjusted so that it became, and it was dissolved in the kneading water in advance and added, and then used for concrete production. About the obtained concrete, air amount, slump, 30 minutes after kneading,
The amount of air after 60 minutes, slump, compressive strength on the 7th and 28th days of age, and the bubble spacing coefficient of the cured specimen were measured.

[0034]

[Table 4] Table 4: Concrete mix floor material W / FC S / a mix (kg / m ³ ) FA type (%) (%) FC W S G 58.3 44 300 175 763 1014 61.0 45 300 183 771 985 FC: fly ash + cement (fly ash content 20%) S / a = [volume of fine aggregate / (volume of fine aggregate + volume of coarse aggregate)] × 100 (%)

Examples 1 to 11 Examples 1 to 11, using the air entraining agents A to N shown in Table 2,
The results of evaluation of the concretes obtained in Comparative Examples 1 to 6 are summarized in Table 5.

[0036]

[Table 5]Table 5: Evaluation results FASlump (cm) Air volume (%) Between bubblesCompressive strength Air entrainment agent Immediately after seed 30 minutes 60 minutes Immediately 30 minutes 60 minutes Separation coefficient (kgf / cm²) Type Usage * After after (after) (μm) 7 days 28 days Example No. 1 A 0.0016 8.0 7.3 5.8 4.8 4.5 4.3 188 130 217 2 B 0.0014 7.7 6.8 5.7 5.2 4.9 4.5 185 128 222 3 C 0.0014 8.2 7.1 6.1 5.0 4.6 4.3 190 131 215 4 C 0.0015 8.1 7.0 5.9 4.8 4.5 4.2 173 125 219 5 D 0.0012 8.4 7.3 6.4 5.0 4.8 4.6 175 131 211 6 D 0.0013 8.2 7.2 6.0 5.2 4.9 4.6 179 126 221 7 E 0.0015 8.0 7.0 5.7 4.9 4.6 4.3 180 137 220 8 F 0.0016 8.2 7.0 5.6 5.1 4.6 4.4 181 125 217 9 G 0.0018 8.0 6.8 5.5 5.0 4.4 4.1 172 128 213 10 H 0.0017 7.9 6.7 5.5 5.1 4.4 4.0 196 133 22611 I 0.0018 8.2 7.1 6.0 5.0 4.5 4.1 201 134 214 Comparative Example No. 1 J 0.0042 8.1 4.8 3.8 4.8 3.3 2.3 490 120 188 2 K 0.0045 8.2 4.7 3.5 5.3 3.6 2.5 523 130 190 3 L 0.0089 8.3 4.7 3.3 5.0 3.4 2.4 578 115 178 4 M 0.0121 7.9 4.5 3.1 5.1 3.5 2.3 601 110 181 5 N 0.0036 8.0 5.0 3.2 4.7 3.5 2.7 488 123 191 6 N 0.0060 8.2 5.2 3.4 5.2 3.0 2.6 555 118 185 *: The amount used is% by weight of the active component of the air entraining agent relative to FC (fly ash + cement)

As can be seen from the examples in Table 5, the composition of the present invention has a small amount used for entraining about 5% of air, is not only excellent in air entrainment, but also has an air entrainment of up to 60 minutes. The quantity retention is also good. The bubble spacing coefficient, which is an index of freeze-thaw resistance, was 500 μm to 6 of Comparative Example.
Compared with 00 μm, the product of the present invention is as small as 200 μm or less,
It is suggested to have sufficient freeze-thaw resistance. In addition, the product of the present invention also exhibits excellent effects on slump retention and compressive strength. When different types of fly ash were evaluated with the same air entraining agent (Example 5,
6 and Comparative Examples 5 and 6), it can be seen that the product of the present invention exerts a stable effect without being affected by the amount of air entrained by the amount of unburned carbon remaining in the fly ash.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuaki Ukita Marunouchi No. 2-5, Takamatsu City, Kagawa Prefecture Techno Resources Co., Ltd. (72) Mitsuhiro Ishii No. 2-5 Marunouchi, Takamatsu City, Kagawa Prefecture Techno Re Source Co., Ltd. (72) Inventor Hironobu Murai No. 2-5 Marunouchi, Takamatsu City, Kagawa Techno Resources Co., Ltd. (72) Inventor Katsushi Matsui 1-3-7 Homsho, Sumida-ku, Tokyo Lion Shares In-house (72) Inventor Naoki Kobayashi 1-3-7 Main Office, Sumida-ku, Tokyo Lion Co., Ltd. (72) In-house Junichi Yamada 1-3-7 Main Office, Sumida-ku, Tokyo Lion Co., Ltd.

Claims (1)

[Claims] (A) At least one kind of anionic surfactant represented by the following general formula (1): 99 to 1 part by weight, and R ¹ -COOM (1) (R ¹ : Alkyl group or alkenyl group having 8 to 30 carbon atoms M: Alkali metal, alkaline earth metal or alkanolamine) (B) At least one kind of amine derivative represented by the general formula (2) of Chemical formula 2 below: 1 to 99 Parts by weight (R ^2: an alkyl group or an alkenyl group m of 8 to 22 carbon atoms, n: each an integer of 1 or more, m + n = 2~50)
An air entraining agent for a cement composition containing fly ash, which comprises: