JP3504346B2 - Air entrainer for cement composition and cement composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an air entraining agent used for cement compositions such as concrete, mortar, paste and grout. More specifically, the present invention relates to an air entraining agent having excellent air entrainment performance for a cement composition containing an unburned carbon-containing admixture such as fly ash and silica fume.

[0002]

BACKGROUND ART Conventionally, for the purpose of improving workability when using a cement composition and improving durability against freeze-thaw of the cement composition, an air entraining agent is added to the cement composition to generate an appropriate amount of air. Entrainment is widely practiced, and in general, this air entraining agent is an AE agent (hereinafter referred to as A
It is also referred to as “E agent”), and examples of the AE agent include resin acid salts, higher alcohol sulfuric acid ester salts, higher alcohol ethylene oxide adduct sulfuric acid ester salts, alkyl sulfonates, and alkyl aryl sulfonates. Those containing an anionic surfactant as a component have been used.

By the way, a cement composition containing an unburned carbon-containing admixture such as fly ash has the following two problems when air is entrained using an AE agent. 1) The air entrainment performance of the AE agent deteriorates. 2) The air entrained in the cement composition during transportation is reduced. It is understood that this is because the added AE agent is adsorbed by the unburned carbon contained in the fly ash, and the performance of the added AE agent is inhibited.

Further, in recent years, the combustion temperature of coal in a thermal power plant has been kept lower than before by environmental protection measures such as emission control of sulfur oxides and nitrogen oxides. The amount of unburned carbon contained in the ash tends to gradually increase. In addition, since coal, which is a fuel, is mostly dependent on imports, coal from different production areas is used at the same power plant, which causes fluctuations in the amount of unburned carbon contained in fly ash. It is a cause. Therefore, the quality variation between lots of fly ash becomes large, and as a result, the air content of the cement composition containing the fly ash also largely varies, and in the technical field, it is difficult to take measures against it. is there.

In such a situation, even when the content of unburned carbon in the fly ash is large, air is entrained at a low usage amount, there is no decrease in the amount of air over time, and the content of unburned carbon is contained. Various AE agents have been proposed in order to obtain an AE agent that does not affect the amount of air in the cement composition even if the amount changes. For example, Japanese Patent Fair 1-3
No. 0776, a cement comprising a fatty acid soap-based anionic surfactant, a nonionic component selected from the group consisting of a cleaning component of sulfonic acids, a higher alcohol sulfate ester salt, polyethylene glycol, an ethoxylated alkylphenol, and a diethanolamine adduct of a fatty acid amide. AE agents for the composition are described. But,
Since this AE agent has poor air bubble strength, the amount used as the AE agent is large, so there is a problem in economic efficiency, and since the amount used is large, the amount of air in the cement composition increases more than necessary over time. In some cases, this may cause the original function of the cement to deteriorate.

Further, JP-A-59-174555 discloses an AE agent for fly ash concrete which contains an ester type nonionic surfactant as a component.
Since the air entrainment performance of this AE agent is also small,
It is not economically satisfactory because the amount used as E agent increases.

Further, JP-A-2-180739 discloses an A for fly ash concrete comprising a fatty acid type anionic surfactant and an ester type nonionic surfactant.
Although the E agent is described, this AE agent does not have sufficient performance against variation in quality of fly ash and is not satisfactory.

As described above, at the present time, when an unburned carbon-containing admixture such as fly ash is used, an AE for obtaining a cement composition of stable quality is obtained.
There is a strong demand for the development of an AE agent that can be satisfied both practically and economically. Therefore, an object of the present invention is to improve the adsorbability of the AE agent to unburned carbon in the admixture to prevent a decrease in the air entrainment performance of the AE agent, and to carry and drive a cement composition such as fresh concrete. Provide an AE agent for a cement composition in which the amount of air entrained in the cement composition does not decrease so much and the amount of air entrained in the cement composition does not fluctuate even if the amount of unburned carbon in the admixture changes To do.

[0009]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above problems, the present inventors have found that a fatty acid-based surfactant and a nonionic surfactant obtained by addition-polymerizing ethylene oxide with alkylphenyl And a mixture obtained by further adding one or more salts selected from alkyl sulfonate, alkyl aryl sulfonate, higher alcohol sulfate ester salt, rosinate and the like to the mixture of Cement composition that has excellent air entrainment performance and stable air content for a long time in a cement composition containing a carbon-containing admixture, and that the air content does not fluctuate even if the unburned carbon content in the admixture fluctuates The inventors have found that it is an AE agent effective for economically producing AE and completed the present invention.

That is, the present invention is an air entraining agent for use in a cement composition containing an unburned carbon-containing admixture, which has the general formula RCOOH (R is a carbon atom having 12 to 24 carbon atoms).
Of a carboxylic acid or an alkali metal salt thereof, a lower alkylamine salt or a lower alkanolamine salt thereof represented by the formula (4), a general formula, R-substituted phenyl-O. −
_{(-CH 2 CH 2 O-) n} -H (R is 8 carbon atoms
9 alkyl group, n is an integer of 1 to 50) and a nonionic surfactant (B) represented by the formula, an air entraining agent for cement composition, an alkyl sulfonate, an alkyl An air entraining agent for a cement composition, which further comprises one or more salts (C) selected from aryl sulfonates, higher alcohol sulfate ester salts, and rosin acid salts. is there. Furthermore, the present invention provides a cement composition containing the air entraining agent and fly ash having a loss on ignition of 5% or more.

The present invention will be described in detail below. The AE agent of the present invention is the same as the fatty acid-based surfactant (A) described above.
To 90% by weight, 90 to 10% by weight as the nonionic surfactant (B), and alkyl sulfonates,
A mixture containing 20 wt% or less of one or more salts (C) selected from alkylaryl sulfonates, higher alcohol sulfates, and rosinates is preferable. The mixing ratio of the fatty acid-based surfactant (A) and the nonionic surfactant (B) is appropriately adjusted at a mixing ratio in the range of A = 10 to 90% by weight and B = 90 to 10% by weight. Excellent air entrainment performance is demonstrated depending on the amount used. The component of one or more salts (C) selected from alkyl sulfonates, alkyl aryl sulfonates, higher alcohol sulfate salts, and rosin acid salts are
A for obtaining a desired amount of air by adding at a ratio of 20% by weight or less with respect to the components (A) and (B)
The total amount of E agent used can be reduced, but 20% by weight
If it exceeds, the stability of the amount of air with time decreases, which is not preferable.

In the present invention, the fatty acid-based surfactant (A) consisting of the carboxylic acid represented by the above general formula RCOOH or a salt thereof has a structure in which the alkyl group or alkenyl group of R is a straight chain or a branched chain. Either may be used, as the salt of the carboxylic acid, alkali metal salts such as sodium and potassium, lower alkylamine salts such as triethylamine or lower alkanolamine salts such as triethanolamine are preferable, and specifically, tall oil fatty acid soap,
Examples thereof include oleic acid soap, linoleic acid soap and coconut fatty acid soap, and tall oil fatty acid soap is particularly preferable.

Further, the above general formula, R-substituted phenyl-O-
The _(-CH 2 _CH 2 O-) nonionic surface active agents represented by n-H (B), the alkyl group of the formula in which R may be linear, branched, specifically poly Examples thereof include oxyethylene nonyl phenyl ether and polyoxyethylene octyl phenyl ether. When the added mole number (n) of ethylene oxide is in the range of 1 to 50 moles, the effect of improving the adsorbability to unburned carbon in the admixture can be obtained. As the number of moles (n) of ethylene oxide added is smaller, the adsorbability is improved, the air entrainment performance can be improved, and the amount of the AE agent used can be reduced. Taking into consideration the tendency of the solubility to be reduced, those having a range of 20 to 30 moles are particularly preferable.

The alkyl group of the alkyl sulfonates and the alkyl aryl sulfonates may be linear or branched, and its salt is preferably an alkali metal salt such as sodium or potassium, or a triethanolamine salt. Include α-olefin sulfonate, alkylbenzene sulfonate, alkyl sulfate, and the like. The higher alcohol sulfate ester salts are those obtained by sulfating a higher alcohol having 12 or more carbon atoms or an ethylene oxide adduct thereof, and include polyoxyethylene alkyl ether sulfate ester salts and polyoxyethylene alkylphenyl ether sulfates. Ester salts may be mentioned. Examples of the rosin acid salt include rosin soap obtained by saponifying pine resin with sodium hydroxide and potassium hydroxide, sodium, potassium, and triethanolamine salts of abietic acid.

The AE agent of the present invention is particularly effective for an unburned carbon-containing admixture-containing cement composition. Examples of the unburned carbon-containing admixture material include fly ash and silica fume.

The unburned carbon contained in the fly ash adsorbs the AE agent, and when the content is high, the amount of the AE agent used remarkably increases in order to carry the desired amount of air, or However, there is a problem that the amount of air decreases remarkably over time, and it has been difficult in the prior art to entrain stable air bubbles in the cement composition. Further, when the ignition loss is significantly different due to the difference in the lot of fly ash, the amount of air entrained in the cement composition fluctuates greatly due to the fluctuation of the ignition loss. Is JIS
A 6201 specifies that the loss on ignition is 5% or less. The AE agent of the present invention, even when using fly ash having a loss on ignition of 5% or more in the cement composition, produces stable air at a low amount of use, as compared with the commonly used AE agent for fly ash. Since it can be carried and fly ash with different ignition loss can also reduce the fluctuation of the air amount, it has a large content of unburned carbon and a large ignition loss. Even if the fly ash which is incompatible with the above is used, it is possible to produce a cement composition of stable quality.

When the AE agent of the present invention is added to a cement composition, it is generally added in the form of an aqueous solution. The water reducing agent, AE water reducing agent, and high-performance agent that have been conventionally used in cement compositions. It can also be used in combination with a water reducing agent, a high-performance AE water reducing agent, a fluidizing agent, a waterproofing agent, a rust preventive, a shrinkage reducing agent, and the like.

The amount of the AE agent of the present invention to be used varies depending on the desired amount of air and the type of material used in the cement composition, but is calculated as solid content based on the total weight of the cement and the admixture in the cement composition. Can be used in the range of 0.001 to 0.1% by weight. However, it is not limited to this range.

【Example】

Example 1 1) Test method a. Mixing method of concrete Using a forced mixer of 100 liter capacity, fine aggregate,
Cement and kneading water (including AE water reducing agent and AE agent) were added and kneaded for 30 seconds, then coarse aggregate was added, kneaded for 90 seconds and discharged. b. Change of concrete with time Slump of mixed concrete (JIS A 11
01), after measuring the air amount (JIS A 1128), it was transferred to a tilting mixer with a capacity of 100 liters and agitated at a tilt angle of the mixer of 15 degrees and a rotation speed of the mixer of 2 rpm for 30 and 60 minutes. The amount of air afterward was measured.

2) Materials used a. Cement: Each ordinary Portland cement made by Onoda, Sumitomo, and Mitsubishi Materials (specific gravity = 3.16)
Were mixed in equal amounts and used. b. Fly ash: Commercial fly ash (specific gravity =
2.26, specific surface area = 3410 cm ² / g, loss on ignition =
3.9%, methylene blue adsorption amount = 0.9 mg / g) was used. c. Fine aggregate: Oi River water-based land sand (specific gravity = 2.64, coarse grain ratio = 2.76) was used. d. Coarse aggregate: Crushed stone from Ome, Tokyo (maximum size = 20 mm,
Specific gravity = 2.65, coarse grain ratio = 6.63) was used. e. Kneading water: Tap water was used. f. AE water reducing agent: An AE water reducing agent (trade name: Pozzolis No. 70) manufactured by NMB Co., Ltd. was used. g. AE agent: The components shown below were used.

As the fatty acid-based surfactant (A), potassium hydroxide saponification of tall oil, nonionic surfactant (B), ethylene oxide of polyoxyethylene nonylphenyl ether 10, 20, 25, 30, 40, 50
Molar adduct (hereinafter, respectively b1, b2, b3, b
4, abbreviated as b5, b6) As a component of (C), sodium dodecylbenzene sulfonate (hereinafter abbreviated as c1), potassium rosin acid saponified hydroxide (hereinafter abbreviated as c2), α-olefin sulfone Acid soda (hereinafter abbreviated as c3) Polyoxyethylene nonylphenyl ether sodium sulfate (hereinafter abbreviated as c4)

3) Mixing of concrete and test results Concrete mixing was performed with a target slump of 18 ± 2 cm.
The target air amount is 5 ± 0.5%, no fly ash is mixed, and fly ash is 20% of cement relative to cement.
The blending percentage was determined by trial kneading. The composition is shown in Table 1.

[0023]

[Table 1]

Concrete was produced with this composition, and the obtained concrete was tested for the amount of air and the change with time of the amount of air. The results are shown in Tables 2 and 3.

[0025]

[Table 2]

Experiment No. 2 in Table 2 13, No. 17-21
Is the addition mole number of ethylene oxide of polyoxyethylene nonylphenyl ether used as the nonionic surfactant (B) is 10 (b1), 20 (b2), 25
(B3), 30 (b4), 40 (b5), 50 (b6)
It is when changing to. The amount of the AE agent used tended to decrease as the number of moles of ethylene oxide added decreased. The solubility of the nonionic surfactant (B) in water decreases as the number of moles of ethylene oxide added decreases, and the solution stability of the AE agent decreases. Therefore, the number of moles of ethylene oxide added is not practical. 2
Those in the range of 0 to 30 mol are preferable.

Experiment No. 2 in Table 2 Nos. 1 to 7 are cases in which fly ash was not mixed, but when the mixing ratio of the component (B) was increased, the AE for obtaining the target air amount was obtained.
The amount of agent used is the case without addition of component (B) (Experiment No. 1)
The tendency was to increase compared to. However, the experiment No. containing the fly ash was mixed. In the case of 10 to 16, the amount of the AE agent used to obtain the target air amount when the mixing ratio of the component (B) is 10 to 90% is the same as that of the component (A) (Experiment N).
o. 10) and the component (B) alone (Experiment No. 16) decreased, and the ratio of the component (A) to the component (B) was 25:
In the case of 75% by weight, the smallest amount was used. (See Figure 1)

Experiment No. Nos. 8 and 9 are the cases where the rosinate-based commercially available AE agent (c2) was used, and although the target air amount was obtained immediately after kneading, when fly ash was mixed (Experiment No. 9), The amount of air greatly decreases with time.

Table 3 shows the components (A) and (B),
Further, as the component (C), sodium dodecylbenzene sulfonate (c1), a potassium hydroxide saponification product of rosin acid (c)
2), sodium α-olefin sulfonate (c3), sodium polyoxyethylene nonylphenyl ether sulfate (c)
It is a result when 4) is used together. Experiment Nos. 26 to 29 in Table 3 are cases in which fly ash was mixed, but the AE agent combined with these components (C) was excellent in air entrainment performance and stable for a long time with a smaller usage amount. Holds the amount of air. Experiment No. No. 30 is the case where the mixing ratio of the potassium hydroxide saponification product of rosin acid is 25% by weight, and the air amount decreases with the passage of time.

[0030]

[Table 3]

Example 2 1) Test method a. Mixing method of concrete Using a forced mixer with a capacity of 50 liters, add fine aggregate, cement and mixing water (including AE water reducing agent and AE agent), mix for 30 seconds, and then add coarse aggregate. Then, it was mixed for 90 seconds and discharged. The tests are concrete slump (JIS A 1101), air volume (JIS A 11
28) was measured.

2) Materials used a. Cement: Each ordinary Portland cement made by Onoda, Sumitomo, and Mitsubishi Materials (specific gravity = 3.16)
Were mixed in equal amounts and used. b. Fly ash: Eight lots (F1 to F8) of fly ash produced from the same power plant and having different ignition losses were used. Table 5 shows the specific gravity, loss on ignition, and methylene blue adsorption amount of these fly ash. c. Fine aggregate: Oi River water-based land sand (specific gravity = 2.64, coarse grain ratio = 2.76) was used. d. Coarse aggregate: Crushed stone from Ome, Tokyo (maximum size = 20 mm,
Specific gravity = 2.65, coarse grain ratio = 6.63) was used. e. Kneading water: Tap water was used. f. AE agent: The following AE agents were used.

AE1: 50% by weight of potassium hydroxide saponification of tall oil as the fatty acid surfactant (A), and 25 mol of ethylene oxide adduct of polyoxyethylene nonylphenyl ether as the nonionic surfactant (B). Mixed at a rate of 50% by weight. AE2: 35% by weight of potassium hydroxide saponification of tall oil as the fatty acid-based surfactant (A) and 60% by weight of 25 mol adduct of ethylene oxide of polyoxyethylene nonylphenyl ether as the nonionic surfactant (B). , And 5% by weight of saponified potassium hydroxide of rosin acid
Were mixed in the ratio.・ AE3: AE agent manufactured by NMB Co., Ltd. (trade name:
No. The main component is 303A, an alkylaryl sulfonate. ) ・ AE4: AE for fly ash manufactured by Toho Chemical Industry Co., Ltd.
Agent (commercial name: CEMEROL T-80, containing polyoxyethylene sorbitan monooleate as a main component)

3) Mixing of concrete and test results The amount of the AE agent used is determined so that an air amount of about 5% can be obtained when fly ash (F4) having an almost intermediate ignition loss is used. A test was conducted on the variation of the air amount due to the lot variation of fly ash when the determined amount of use was used. A composition in which fly ash was mixed in an amount of 20% based on the weight of cement was determined by trial milling. The formulation is shown in Table 4.

[0035]

[Table 4]

The test results are shown in Tables 5 and 6. As shown in Table 5, the coefficient of variation is 10.0% in the range of 3.7 to 5.2% for the air volume of AE1 and 3.7 to 5.2 for the air volume of AE2.
%, The coefficient of variation is 9.8%, while AE
The amount of air of 3 has a coefficient of variation of 3 in the range of 2.5 to 7.0%.
5.2%, the amount of air of AE4 is 2.7 to 6.4%, the coefficient of variation is 25.0%, AE1 and AE2 are
Compared with E3 and AE4, even if the ignition loss of fly ash fluctuated with a small amount used, the fluctuation of the air amount was extremely small, and a stable air amount was obtained.

[0037]

[Table 5]

[0038]

[Table 6]

Table 6 shows AE1, AE2, AE3, AE4.
It is the result of having tested the time-dependent change of the air volume of the concrete which used. The air content of the concrete using AE1 and AE2 shows almost no decrease even after 60 minutes have passed. However, in the case of AE3, AE1
As compared with AE2 and AE2, a desired amount of air can be entrained with a smaller amount of use, but the amount of air decreases significantly after 60 minutes. Further, in the case of AE4, although the decrease in the air amount after a lapse of 60 minutes is slight, the amount of use thereof is extremely large as compared with AE1 and AE2.

[0040]

The cement composition containing the air entraining agent according to the present invention has a small change in the amount of air over time, can hold stable air for a long time, and has unburned carbon in the admixture. It is possible to carry a stable amount of air even if the content of is changed.

[Brief description of drawings]

FIG. 1 shows the relationship between the mixing ratio of component (A) and component (B) and the amount of AE agent used.

Front page continuation (51) Int.Cl. ⁷ Identification code FI C04B 24/16 C04B 24/16 24/32 24/32 A 24/34 24/34 28/02 28/02 // C04B 103: 30 103: 30 103: 40 103: 40

Claims (5)

(57) [Claims] 1. An air entraining agent for use in a cement composition containing an unburned carbon-containing admixture, which has the general formula: RCO
A fatty acid-based surfactant (A, which is a carboxylic acid represented by OH (R is an alkyl group or alkenyl group having 12 to 24 carbon atoms) or its alkali metal salt, lower alkylamine salt or lower alkanolamine salt (A 10 to 90% by weight and the general formula, R-substituted phenyl-O
_{- (- CH 2 CH 2 O-} ) n -H (R is 8 carbon atoms
9. An air entraining agent for cement composition, comprising 90 to 10% by weight of the nonionic surfactant (B) represented by the alkyl group 9 and n is an integer of 1 to 50). 2. The composition further contains one or more salts (C) selected from alkyl sulfonates, alkylaryl sulfonates, higher alcohol sulfate ester salts, and rosin acid salts. Item 1. An air entraining agent for a cement composition according to Item 1. 3. The air entraining agent for a cement composition according to claim 2, which contains 20% by weight or less of the salt (C). 4. The air entraining agent for a cement composition according to claim 1, wherein an admixture containing fly ash is blended as the unburned carbon-containing admixture. 5. A cement composition comprising a fly ash having an ignition loss of 5% or more and the air entraining agent for cement composition according to any one of claims 1 to 3. object.