JPH0517182B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a concrete composition for underwater construction that is easy to mix and contains an admixture that prevents separation of concrete composition materials during underwater pouring. Conventional technology Conventionally, when concrete is poured underwater, as the concrete falls into the water or spreads laterally, the cement paste is washed away from the concrete in the area that is in contact with the water. The cement paste dispersed and became non-uniform, reducing the strength of the concrete that was placed. At the same time, the separated cement paste portions spread into the water, significantly polluting the water. In order to solve these problems, it has been disclosed (German Patent Publication No. 2541747) that a cellulose dielectric and polyacrylamide, that is, an acrylamide homopolymer, are added to concrete as an admixture. A compound containing a partially hydrolyzed compound is disclosed in JP-A-59-54656. Problems to be Solved by the Invention In the above-mentioned conventional techniques, the former has the disadvantage that the setting of concrete is delayed compared to concrete that does not contain an admixture, and the initial strength of concrete that has been placed is particularly reduced; This admixture has excellent characteristics as concrete for underwater construction in that it does not delay the initial strength or reduce the initial strength, but like acrylamide homopolymer, this admixture also has a strong cohesive effect on cement, making the concrete hard and difficult to mix. It becomes difficult to mix, and not only does it take time to mix to obtain a uniform composition, but the load on the mixing machine increases, making it impractical. Means for solving the problems The means of the present invention for solving the above problems are as follows: (1) General formula [] (In the formula, R ¹ is a hydrogen atom or a lower alkyl group, and R ^{2 and} R ³ are both the same or different and are lower alkyl groups, or one is hydrogen and the other is a lower alkyl group. and R ³ are bonded to each other with or without an oxygen atom together with the nitrogen atom to which they are bonded.
Alternatively, a 6-membered ring may be formed. ) A concrete composition for underwater construction containing 0.1 to 4% by weight of cement of a water-soluble polymer compound with a molecular weight of 1 million or more obtained by polymerizing an acrylic monomer represented by: (2) General formula [] (In the formula, R ¹ is a hydrogen atom or a lower alkyl group, and R ^{2 and} R ³ are both the same or different and are lower alkyl groups, or one is hydrogen and the other is a lower alkyl group. and R ³ are bonded to each other with or without an oxygen atom together with the nitrogen atom to which they are bonded, resulting in 5
Alternatively, a 6-membered ring may be formed. ) The acrylic monomer represented by the general formula [] [In the formula, R ⁴ represents a hydrogen atom or a lower alkyl group, and A represents -CONH ₂ , -CN or -COOR ⁵
(R ⁵ represents a hydrogen atom, a lower alkyl group, a lower hydroxyalkyl group, an alkali metal or ammonium.) ] Molecular weight 100 obtained by polymerizing with an acrylic monomer represented by
More than 10,000 water-soluble polymer compounds are added to the cement weight.
Concrete composition for underwater construction containing 0.1 to 4%. (3) General formula [] (In the formula, R ¹ is a hydrogen atom or a lower alkyl group, and R ^{2 and} R ³ are both the same or different and are lower alkyl groups, or one is hydrogen and the other is a lower alkyl group. and R ³ are bonded to each other with or without an oxygen atom together with the nitrogen atom to which they are bonded, resulting in 5
Alternatively, a 6-membered ring may be formed. ) The acrylic monomer represented by the general formula [] [In the formula, R ⁴ represents a hydrogen atom or a lower alkyl group, and A represents -CONH ₂ , -CN, or -
COOR ⁵ (R ⁵ represents a hydrogen atom, a lower alkyl group, a lower hydroxyalkyl group, an alkali metal or ammonium). ] Acrylic monomer and general formula [] [In the formula, R ⁶ represents a hydrogen atom or a lower alkyl group, and B represents -CH ₂ -, -CONHCH ₂ -,

[Formula] (R ⁷ and R ⁸ are the same or different and represent a hydrogen atom or a lower alkyl group.) or

[Formula], n represents an integer of 0 or 1, and M represents a hydrogen atom, an alkali metal or ammonium. ] This is a concrete composition for underwater construction containing 0.1 to 4% of the cement weight of a water-soluble polymer compound with a molecular weight of 1 million or more obtained by polymerization with a vinyl monomer represented by the following. Effects Examples of the acrylic monomer represented by the general formula [] used as a raw material for the water-soluble polymer compound used in the present invention include N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N,N-diethylacrylamide, N-acryloylpiperidine, N-acryloylmorpholine, N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N,N-dimethylmethacrylamide, N ，
Mention may be made of N-diethylmethacrylamide, N-methacryloylpiperidine and N-methacryloylmorpholine. Examples of the acrylic monomer represented by the general formula [] include acrylamide, acrylonitrile, methyl acrylate, ethyl acrylate, hydroxyethyl acrylate, acrylic acid, sodium acrylate, methacrylamide, methacrylonitrile, and methacrylic acid. Mention may be made of methyl, ethyl methacrylate, hydroxyethyl methacrylate, methacrylic acid and methacrylic acid sodium salt. Examples of the vinyl monomer represented by the general formula [] include acrylamide methanesulfonic acid, 2-acrylamidoethanesulfonic acid, 2-acrylamidoethanesulfonic acid,
-acrylamidopropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, methacrylamide methanesulfonic acid, 2-
methacrylamide ethanesulfonic acid, 2-methacrylamidopropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid,
Examples include vinyl sulfonic acid, styrene sulfonic acid, or alkali metal salts and ammonium salts thereof. The water-soluble polymer compound used in the present invention can be produced by polymerizing the acrylic monomer represented by the general formula [] by a conventional method, or by polymerizing the acrylic monomer represented by the general formula [] and the general formula A mixture with an acrylic monomer represented by [] is polymerized by a conventional method, or an acrylic monomer represented by the general formula [], an acrylic monomer represented by the general formula [], and a general It is carried out by polymerizing a mixture of vinyl monomers represented by the formula [] by a conventional method, and at this time, the general formula [],
As each monomer represented by [ ] and [ ], two or more types of monomers represented by the respective formulas can also be used in combination. The polymerization is preferably carried out in an aqueous medium using a radical polymerization initiator such as a peroxide or an organic azo compound. The molecular weight of the polymer varies depending on the type and amount of polymerization initiator used, but it can range from 1 million to about 20 million. When the polymerization reaction is carried out in an aqueous medium, some water-soluble polymer compounds may contain a large amount of carboxyl groups, so the polymerization reaction should be carried out in a neutral liquid or at a low temperature. desirable. In the water-soluble polymer compound used in the present invention, the water-soluble polymer compound obtained by polymerizing the acrylic monomer represented by the general formula [] does not exhibit an agglomerating effect on concrete and dissolves quickly, so the present invention Mixing concrete is very easy. A water-soluble polymer compound obtained by polymerizing an acrylic monomer represented by the general formula [] together with an acrylic monomer represented by the general formula [] or an acrylic monomer represented by the general formula [] In the case of a water-soluble polymer compound obtained by polymerizing the acrylic monomer represented by the general formula [] and the vinyl monomer represented by the general formula [], the acrylic monomer represented by the general formula [] As the copolymerization mole of the polymer increases, the agglomerating effect on concrete becomes smaller and the dissolution becomes faster, making it easier to mix the concrete composition of the present invention. The preferred molar ratio of the acrylic monomer used is 5% or more. In addition, since water-soluble polymer compounds containing a large amount of carboxyl groups tend to exhibit a flocculating effect on concrete, an acrylic monomer in which A is -COOH or a salt thereof in the general formula [] is used. In this case, the molar ratio used is preferably 5% or less. The molecular weight of the water-soluble polymer compound used in the present invention is not particularly problematic as long as it has a high molecular weight to sufficiently impart the property of not separating in water to the concrete composition, but it is preferably 1 million or more. The amount added is based on the cement of the concrete composition.
A content of 0.1% by weight or more is required, and if it exceeds about 4% by weight, it is not only uneconomical but also becomes a viscous material that is difficult to handle, resulting in a decrease in compressive strength, etc. In the concrete composition of the present invention, the water-soluble polymer compound can be mixed in advance with cement, added to ready-mixed concrete, or dissolved in water beforehand and added to ready-mixed concrete. Good too. At that time, concrete dispersant,
For example, melamine sulfonic acid formalin condensate,
The fluidity of concrete can be further improved by adding appropriate amounts of sulfonic acid derivatives such as naphthalene sulfonic acid formalin condensate and lignin sulfonate. Moreover, an antifoaming agent or an air entraining agent can also be used in combination, if necessary. Examples Examples of the present invention will be described in detail below. Example 1 A water-soluble polymer compound with a molecular weight of approximately 7 million obtained by polymerizing an acrylic monomer represented by the general formula [] was blended at 1% by weight with respect to the cement in the concrete shown in Table 1, The state of the mixed concrete was observed when it was mixed using a single-shaft forced mixing mixer with a capacity of 50, and the mixed concrete was subjected to an underwater drop test and a compressive strength test.

[Table] In the underwater drop test, a concrete specimen was filled in a conical trapezoidal container with a diameter of 5 cm at the bottom, 7 cm at the top, and 8 cm deep, and this was filled with water to a depth of 16 cm in advance, 20 cm in diameter and 26 cm deep. in a cylindrical container above the water surface.
The water was allowed to fall naturally from a position of 10 cm, and the transmittance of the turbidity of the water at this time was measured using a photoelectric photometer at a wavelength of 660 mμ. The higher the transmittance, the smaller the amount of cement in the concrete that has escaped into the water, which means that there is less deterioration in the quality of the concrete. For the compressive strength test, a cylindrical specimen with a diameter of 15 cm and a height of 30 cm was taken from the mixed concrete.
The samples were cured in water at ℃ and tested on the 7th and 28th day of age. The mixing state of concrete was displayed in three stages. A: Within 2 minutes after the start of kneading, the mixture becomes fluid and homogeneous, and the required slump value is obtained.
The kneading condition is good. B: After the start of mixing, the concrete becomes hard, but only temporarily; it becomes fluid and homogeneous within 7 minutes, and the desired slump value is obtained. C: After the mixing starts, the concrete aggregates and becomes hard, making mixing difficult. In order to obtain a uniform state with fluidity, it is necessary to knead and mix for at least 7 minutes, which is not good. For comparison, concrete containing no water-soluble polymer compound (plain concrete), polyacrylamide (molecular weight 7 million) and polyacrylamide partially hydrolyzed compound (molecular weight approx.
A similar test was also conducted on concrete containing 1% by weight of cement. The results are shown in Table 2.

[Table] Example 2 For a water-soluble polymer compound cement with a molecular weight of approximately 7 million obtained by polymerizing an acrylic monomer represented by the general formula [] together with an acrylic monomer represented by the general formula [] The same test as in Example 1 was conducted on concrete containing 1% by weight. The results are shown in Table 3.

【table】

[Table] Example 3 Obtained by polymerizing the acrylic monomer represented by the general formula [] together with the acrylic monomer represented by the general formula [] and the vinyl monomer represented by the general formula [] The same test as in Example 1 was conducted on concrete containing 1% by weight of a water-soluble polymer compound with a molecular weight of about 7 million, based on cement. The results are shown in Table 4. Example 4 Concrete containing 1% by weight of water-soluble polymer compounds with different molecular weights obtained by polymerizing N,N-dimethylacrylamide to cement was tested in the same manner as in Example 1 when mixed and mixed. The rate was measured. The results are shown in Table 5.

【table】

[Table] Example 5 Concrete containing 1% by weight of cement with water-soluble polymer compounds having different copolymerization molar ratios and molecular weights obtained by polymerizing N,N-dimethylacrylamide with acrylamide. A similar test was conducted. The results are shown in Table 6. Example 6 Water-soluble polymer compounds with a molecular weight of 7 million with different copolymerization molar ratios obtained by polymerizing N,N-dimethylacrylamide with acrylamide and sodium 2-acrylamide-2-methylpropanesulfonate were applied to cement. A test was conducted in the same manner as in Example 4 on concrete containing 1% by weight. The results are shown in Table 7.

【table】

【table】

[Table] Example 7 A water-soluble polymer compound with a molecular weight of 7 million obtained by polymerizing N,N-dimethylacrylamide was used as the first
It was added to the concrete shown in the table in various amounts and tested in the same manner as in Example 1. The results are shown in Table 8.

[Table] Example 8 A water-soluble polymer compound with a molecular weight of 7 million obtained by polymerizing a mixture of N,N-dimethylacrylamide:acrylamide = 10:90 (mol %) was mixed into concrete shown in Table 1 in various ways. amount was added and tested in the same manner as in Example 1. The results are shown in Table 9.

[Table] Example 9 Aqueous solution with a molecular weight of 7 million obtained by polymerizing a mixture of N,N-dimethylacrylamide: acrylamide: 2-acrylamide-2-methylpropanesulfonate sodium = 10:80:10 (mol %) The polymer compounds shown in Table 1 were added in various amounts to the concrete shown in Table 1 and tested in the same manner as in Example 1. The results are shown in Table 10.

【table】

[Table] Effects of the Invention Since the present invention comprises the above-mentioned means, even if concrete is placed in water, the cement paste portion will not separate, and therefore the strength of the concrete will not decrease and the water will not be polluted. There is no. Moreover, even though an admixture is used, there is no setting delay or decrease in initial strength, and mixing is easy.
A uniform composition can be obtained without spending a long time on kneading and mixing, and there is no need to place a large burden on the kneading machine.

Claims (1)

[Claims] 1. General formula [] (In the formula, R ¹ is a hydrogen atom or a lower alkyl group,
R ² and R ³ are both the same or different and are lower alkyl groups, or one is hydrogen and the other is a lower alkyl group. Further, R ² and R ³ may be bonded to each other with or without an oxygen atom together with the nitrogen atom to which they are bonded to form a 5- or 6-membered ring. ) A concrete composition for underwater construction containing 0.1 to 4% of the weight of cement, which is a water-soluble polymer compound with a molecular weight of 1 million or more obtained by polymerizing an acrylic monomer represented by the following formula. 2 General formula [] (In the formula, R ¹ is a hydrogen atom or a lower alkyl group,
R ² and R ³ are both the same or different and are lower alkyl groups, or one is hydrogen and the other is a lower alkyl group. Further, R ² and R ³ may be bonded to each other with or without an oxygen atom together with the nitrogen atom to which they are bonded to form a 5- or 6-membered ring. ) The acrylic monomer represented by the general formula [] [In the formula, R ⁴ represents a hydrogen atom or a lower alkyl group, and A is -CONH ₂ , -CN, or -COOR ⁵
(R ⁵ represents a hydrogen atom, a lower alkyl group, a lower hydroxyalkyl group, an alkali metal or ammonium.) ] A water-soluble polymer compound with a molecular weight of 1 million or more obtained by polymerization with an acrylic monomer represented by 0.1 to 4% of the weight of cement.
Concrete composition for underwater construction. 3 The acrylic monomer represented by the general formula [] in a water-soluble polymer compound obtained by polymerizing the acrylic monomer represented by the general formula [] together with the acrylic monomer represented by the general formula [] The concrete composition for underwater construction according to claim 2, wherein the copolymerization molar ratio of is 5% or more. 4 The acrylic monomer represented by the general formula [] is the general formula [] The concrete composition for underwater construction according to claim 2, which is an acrylamide represented by the formula (wherein R ⁴ represents a hydrogen atom or a lower alkyl group). 5 General formula [] (In the formula, R ¹ is a hydrogen atom or a lower alkyl group,
R ² and R ³ are both the same or different and are lower alkyl groups, or one is hydrogen and the other is a lower alkyl group. Further, R ² and R ³ may be bonded to each other with or without an oxygen atom together with the nitrogen atom to which they are bonded to form a 5- or 6-membered ring. ) The acrylic monomer represented by the general formula [] [In the formula, R ⁴ represents a hydrogen atom or a lower alkyl group, and A is -CONH ₂ , -CN, or -COOR ⁵
(R ⁵ represents a hydrogen atom, a lower alkyl group, a lower hydroxyalkyl group, an alkali metal or ammonium.) ] Acrylic monomer and general formula [] [In the formula, R ⁶ represents a hydrogen atom or a lower alkyl group, and B represents -CH ₂ -, -CONHCH ₂ -,
[Formula] (R ⁷ and R ⁸ are the same or different and represent a hydrogen atom or a lower alkyl group) or [Formula], n represents an integer of 0 or 1, and M represents a hydrogen atom, an alkali metal or Indicates ammonium. ] A water-soluble polymer compound with a molecular weight of 1 million or more obtained by polymerization with a vinyl monomer represented by 0.1 of the cement weight
Concrete composition for underwater construction containing ~4%. 6 A water-soluble polymer compound obtained by polymerizing an acrylic monomer represented by the general formula [] together with an acrylic monomer represented by the general formula [] and a vinyl monomer represented by the general formula [] The concrete composition for underwater construction according to claim 5, wherein the copolymer molar ratio of the acrylic monomer represented by the general formula [] is 5% or more. 7 The acrylic monomer represented by the general formula [] is the acrylic monomer represented by the general formula [], and the vinyl monomer represented by the general formula [] is the acrylic monomer represented by the general formula [] (In the formula, R ⁶ , R ⁷ and R ⁸ are the same or different and represent a hydrogen atom or a lower alkyl group, and M represents a hydrogen atom, an alkali metal or ammonium.)
The concrete composition for underwater construction according to claim 5, which is an acrylic monomer represented by: