JP2905658B2 - Underwater non-separable concrete composition and defoamer for concrete composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-water inseparable concrete composition and an antifoaming agent for the concrete composition. More specifically, an underwater non-separable concrete composition which is cast in water or in a place with a lot of water, which is capable of separating materials such as aggregates and cement and which can easily control the amount of air. The present invention relates to an antifoaming agent for a concrete composition suitable for a non-separable concrete composition.

[0002]

2. Description of the Related Art When constructing a concrete structure in water, so-called underwater construction is generally performed in which concrete kneaded on land is introduced into water by a pump or the like and constructed. In underwater construction, the cement paste easily flows out due to the falling and moving of the concrete in water or exposure to running water, which not only causes pollution of the surrounding water quality,
There is also a quality problem that the composition of the concrete becomes very uneven and the strength after hardening decreases.
Therefore, underwater construction of concrete has been considered to be a difficult technique that requires special consideration even during various types of concrete construction work.

[0003] In recent years, in order to solve the above-mentioned problems, an underwater concrete composition having high resistance to material separation has been developed and applied to underwater construction such as bridge substructure. In this technology, a thickening agent that dissolves in water and imparts an appropriate viscosity is added to an underwater concrete composition to enhance the cohesiveness of the materials and prevent material separation of aggregates and cement particles. Things. In addition, a water reducing agent is generally used in order to impart fluidity with less mixing water.

[0004]

However, the water-soluble cellulose ether, which is a thickener used in non-separable concrete underwater, has a property of lowering the surface tension, and therefore has an air entrainment property, and the concrete has air. Has the effect of entraining. When a large amount of water-soluble cellulose ether is used as in the case of underwater non-separable concrete, the concrete strength significantly decreased by air entrainment is not preferable.

[0005] For this purpose, an antifoaming agent is used to control the amount of air. As the defoaming agent, those used as cement or gypsum defoaming agents can be used. For example, pluronic antifoaming agents, tributyl phosphate, silicone antifoaming agents, and the like are used.

Of these, pluronic and silicone defoamers are inferior in defoaming performance, and it is difficult to control the amount of air unless added in large amounts. On the other hand, tributyl phosphate is excellent in defoaming performance and has the advantage that the amount of air can be controlled with a small amount. However, when compounded with cellulose ether as a thickener, it has an irritating odor and has difficulty in handling. Further, tributyl phosphate is one kind of plasticizer for synthetic resin, and a compound using the same has a disadvantage that inexpensive vinyl chloride cannot be used as a packaging material.

As described above, conventionally, the defoaming performance is excellent, and the amount of air can be controlled with a small amount of addition.
There are virtually no defoamers that are excellent in handling, and the realization of underwater non-separable concrete with such defoamers has been strongly desired.

Accordingly, it is an object of the present invention to provide a defoamer which is less likely to cause material separation in water, easily controls the amount of air, has no irritating odor when compounded, is easy to handle, and has low handling cost. It is an object of the present invention to provide a non-separable underwater concrete composition for underwater construction using an agent and an antifoaming agent for such a concrete composition.

[0009]

Means for Solving the Problems The present inventors have intensively studied to obtain an antifoaming agent which is excellent in defoaming performance and excellent in handling when compounded. As a result, an acetylene glycol derivative is extremely effective. Find things,
The present invention has been made.

In order to achieve the above object, a water-inseparable concrete composition according to claim 1 is a concrete composition containing a cement binder, an aggregate, and a water reducing agent, wherein the concrete composition comprises hydroxyalkylcellulose, hydroxyalkylalkylcellulose. Or an acetylene glycol derivative as an antifoaming agent.

[0011] To achieve the above object, the invention of claim 2 provides:
2. The composition of claim 1, wherein the acetylene glycol derivative is 2,4,7,9-.
A nonionic surfactant obtained by adding ethylene oxide to tetramethyl-5-decyne-4,7-diol, wherein the number of moles of ethylene oxide added is 1 to 20.

In order to achieve the above object, the antifoaming agent for a concrete composition according to claim 3 is a non-foaming agent obtained by adding ethylene oxide to 2,4,7,9-tetramethyl-5-decyne-4,7-diol. An ionic surfactant comprising an acetylene glycol derivative having an ethylene oxide addition mole number of 1 to 20.

The cement binder used in the present invention includes:
In addition to ordinary Portland cement, inorganic powders such as blast furnace cement, silica cement, fly ash cement, blast furnace slag, fly ash, etc., and also those having a pozzolanic reaction such as stone powder, silica fume, etc. Used in combinations of more than one species.

The types of fine aggregate and coarse aggregate used in the present invention are not limited, and any types can be used. The present invention is also useful in a case such as a cement mortar that does not use coarse aggregate.

The water reducing agent used in the present invention includes a general water reducing agent, a high performance water reducing agent, an AE water reducing agent, and the like. Among these, a high performance water reducing agent is preferable. Examples of the high-performance water reducing agent include a highly condensed triazine compound, a formalin condensate of melamine sulfonate, a polycarboxylate derivative, a modified lignin sulfonate compound, an aminosulfonic acid polymer compound, and a naphthalene sulfonate. Of formalin condensate of conjugated sodium diene sulfonate (co)
Among them, highly condensed triazine compounds, formalin condensates of melamine sulfonates, polycarboxylate derivatives, modified lignin sulfonate compounds, and sodium conjugated diene sulfonate ( Co) polymers are preferred. These water reducing agents are generally
1 to 5% by weight based on the cement binder, preferably 1 to 5%
3% by weight is used.

The water-soluble cellulose ether used in the present invention is used as a thickener to prevent material separation in water, and is a nonionic cellulose ether such as hydroxyethyl cellulose (HEC) or hydroxypropyl cellulose (HPC). And the like. Further, hydroxyalkylalkylcellulose such as hydroxyethylmethylcellulose (HEMC), hydroxypropylmethylcellulose (HPMC), and hydroxyethylethylcellulose (HEEC) can also be mentioned. Among such nonionic water-soluble cellulose ethers, particularly, HP
MC and HEC are preferred. The viscosity is not particularly limited, but is 1% measured using a B-type viscometer.
If the viscosity of the aqueous solution is 500 to 50,000 cP, the object of the present invention can be sufficiently achieved.

The amount of the water-soluble cellulose ether to be added depends on the type thereof, the amount of unit cement, and the like.
0.1 to 5% by weight based on the mixing water, preferably
When added in an amount of 0.3 to 2% by weight, a water-inseparable concrete excellent in material separation resistance can be obtained.

The acetylene glycol derivative used in the present invention includes 2,2 represented by the following structural formula (I).
Those obtained by adding ethylene oxide to 4,7,9-tetramethyl-5-decyne-4,7-diol are preferred.
It is preferable that (m + n) = 1 to 20 in the formula.

[0019]

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That is, the number of moles of ethylene oxide added (m + n) is preferably from 1 to 20, and if it is less than 1, the solubility in water is small and the defoaming performance is poor. When the number of added moles exceeds 20, the solubility in water is large, but this concrete system is inferior in defoaming performance. More preferably, the number of moles of ethylene oxide added is 2 to 15.

The amount of the acetylene glycol derivative used as an antifoaming agent varies depending on the materials used, such as cement and aggregate, the composition, the type and amount of the water-soluble cellulose ether, and the required amount of air. ~ 1,
000 g / m ³ .

A typical example of the underwater non-separable concrete composition according to the present invention is as follows. Cement binder 300 to 500 kg / m ³ Aggregate 1650~1900kg / m ³ water 150 to 240 kg / m ³ non-ionic water-soluble cellulose ether 1.0 to 4.0 kg / m ³ defoamer 0.1 to 0. 4 kg / m ³ water reducing agent 3 to 15 l / m ³

The composition of the present invention can be manufactured according to a conventional method. For example, a water-soluble cellulose ether and an acetylene glycol derivative are added to a cement binder, an aggregate, a water reducing agent and water in a raw plant or at a site. It is manufactured by stirring and mixing. The acetylene glycol derivative which is an antifoaming agent can be used by mixing it with the water-soluble cellulose ether first or by directly adding it to concrete.

[0024]

EXAMPLES Examples and comparative examples of the present invention will be described below, but the present invention is not limited to these examples.

Examples 1 to 5 and Comparative Examples 1 to 5 Maximum aggregate size: 20 mm, fine aggregate ratio (s / a): 40
%, Fine aggregate: 638 kg / m ³ , coarse aggregate: 967 kg /
to the bone material made of m ^3, cement binder: 400kg / m
³ , water: 220 kg / m ³ (water cement ratio: 55.0
%), A thickener, a water reducing agent, and an antifoaming agent as shown below, and kneading 1 with a 55-liter pan mixer.
Of concrete mixed in 3 minutes, main mixing, slump flow, air volume, degree of separation in water (amount of suspended solids, pH) and compressive strength were measured according to the test methods shown below. It was also described in.

Materials used 1) Cement binder: ordinary Portland cement (specific gravity: 3.15, manufactured by Nippon Cement Co.) 2) Fine aggregate: Shinanogawa, river sand (water absorption: 1.92%, specific gravity: 2.60, FM2) .82) 3) Coarse aggregate: Crushed stone from Shimogakugawa, Arai City (water absorption 1.88)
%, Specific gravity 2.63, FM 6.72) 4) Water reducing agent: Reobuild UC-150 (manufactured by Pozoris, high performance water reducing agent) 5) Thickening agent ・ Hydroxyalkylcellulose: Hydroxyethylcellulose (shown as HEC in the table) MS: 2.0, viscosity of 1% aqueous solution 3.500 cP (B-type viscometer) Used in Examples 4 and 5.・ Hydroxyalkylalkylcellulose: hydroxypropylmethylcellulose (shown as HPMC in the table), DS: 1.4, MS: 0.20, 1% aqueous solution viscosity 3,7
00cP (B-type viscometer) Used in other than Examples 4 and 5. 6) Antifoaming agent:-Acetylene glycol derivative: (shown as AG in the table; manufactured by Nissin Chemical Industry Co., Ltd.) Surfynol 104 (mol number of ethylene oxide added: 0) (Comparative Example 1) Surfynol 420 (mol number of ethylene oxide added) 1.5) (Example 1) Surfynol 440 (3.5 moles of ethylene oxide added) (Examples 2 and 4) Surfynol 465 (10.0 moles of ethylene oxide added) (Examples 3 and 5) NOLU 485 (30.0 moles of ethylene oxide added) (Comparative Example 2) Pluronic type: Pluronic L-61 (manufactured by Asahi Denka Kogyo) (Comparative Example 3) Silicone type: KM-73 (manufactured by Shin-Etsu Chemical Co., Ltd.) ) (Comparative Example 4) Tributyl phosphate (Comparative Example 5)

Test method 1) Slump flow: The spread after 5 minutes was measured in accordance with "Japan Society of Civil Engineers, Guideline for Design and Execution of Underwater Inseparable Concrete (Draft), Concrete Slump Flow Test Method (Draft)". 2) Air volume: The test was carried out in accordance with JIS A 1128 (test method based on pressure of air volume of concrete not yet solidified). 3) Underwater separability: Performed in accordance with "Japan Society of Civil Engineers, Guideline for Design and Execution of Underwater Nonseparable Concrete (Draft), Test Method for Underwater Separability of Underwater Nonseparable Concrete (Draft)". 4) Compressive strength: Production in water and production in air (Material age 28
Sun) Prepare underwater specimens in accordance with "Japan Society of Civil Engineers, Guideline for Design and Execution of Underwater Non-separable Concrete (Draft), How to Make Underwater-produced Specimens for Compressive Strength Testing of Underwater Non-separable Concrete (Draft)" An aerial test specimen was prepared.

[0028]

[Table 1]

[Table 2]

As is clear from Table 1, in Examples 1 to 5, since the acetylene glycol derivative of the present invention is used as an antifoaming agent, the air amount control is excellent, and the air amount is reduced to 4% or less with a small addition amount. It can be. Further, similarly to the conventionally used antifoaming agents such as pluronics, silicones and tributyl phosphate, they do not adversely affect fluidity, resistance to separation in water, and compressive strength. In Examples 1, 2, and 3, HP was used as a water-soluble cellulose ether.
Examples in which MC was used, and Examples 4 and 5 are examples in which HEC was used as a water-soluble cellulose ether. HEC
Since the air entrainment is lower than that of HPMC, the amount of the acetylene glycol derivative added is slightly smaller.

On the other hand, in Comparative Examples 1 and 2, the acetylene glycol derivative was used as the defoaming agent. However, the number of moles of ethylene oxide added was not suitable, and the defoaming performance was poor. That is, Comparative Example 1 has a case in which the number of moles of ethylene oxide added is 0, and Comparative Example 2 has a case in which the number of moles of added ethylene is 30. Can not lower. Comparative Examples 3 to 5 are conventionally used antifoaming agents. Comparative Examples 3 and 4 are inferior in defoaming performance. Even if they are added 10 times or more as compared with the examples, the amount of air is larger than in the examples, and it is not easy to control the amount of air. Comparative Example 5 is a case where tributyl phosphate is used, and is excellent in defoaming performance, but when compounded,
Has an irritating odor and has difficulty handling.

As described above, none of the conventional antifoaming agents is excellent in both the antifoaming effect and the handling.

On the other hand, the acetylene glycol derivative used in the present invention has excellent defoaming performance,
When compounded, it does not have an irritating odor like tributyl phosphate, and further has the advantage that, unlike tributyl phosphate, there is no problem even if inexpensive vinyl chloride is used as a packaging material.

[0033]

As is apparent from the above description, according to the present invention, underwater construction using an antifoaming agent which is less likely to cause material separation in water, easily controls the amount of air, and has low handling cost. And a defoamer for such concrete mix compositions.

────────────────────────────────────────────────── (5) Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C04B 103: 50 111: 74 (56) References JP-A-58-115051 (JP, A) JP-A-64-33043 (JP, A) JP-A-2-307851 (JP, A) JP-A-1-160852 (JP, A) JP-A-59-227754 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) ) C04B 24/38 C04B 24/02 C04B 24/32 C04B 28/02-28/08

Claims (3)

(57) [Claims] A concrete composition containing a cement binder, an aggregate, and a water reducing agent is added to a hydroxyalkyl cellulose,
A water-insoluble separable concrete compounding composition, comprising one or more water-soluble cellulose ethers selected from the group consisting of hydroxyalkylalkyl celluloses and an acetylene glycol derivative as an antifoaming agent. 2. The acetylene glycol derivative is 2,2.
A nonionic surfactant obtained by adding ethylene oxide to 4,7,9-tetramethyl-5-decyne-4,7-diol, wherein the number of moles of ethylene oxide added is 1 to 20. 1. An in-water non-separable concrete blending composition. 3. A nonionic surfactant obtained by adding ethylene oxide to 2,4,7,9-tetramethyl-5-decyne-4,7-diol, wherein the number of moles of ethylene oxide added is 1 to 20. An antifoaming agent for a concrete composition, comprising an acetylene glycol derivative.