JP4767093B2 - Dispersant for silica fume slurry, silica fume slurry and method for producing concrete - Google Patents

Description

  The present invention relates to a dispersant for producing a silica fume slurry that facilitates the transportation and handling of silica fume, and particularly a dispersant for producing a silica fume slurry suitable for producing high-strength concrete, and using the same. It is related with the manufactured silica fume slurry and the concrete manufactured using it.

  Silica fume is a siliceous ultrafine particle material that has been used as a concrete admixture for the purpose of improving the strength of concrete by pozzolanic reaction, microfiller effect, and improving the fluidity of concrete with a low water binder ratio. . It is also used for the purpose of improving the working environment, such as reducing the amount of rebound and dust when using shotcrete.

  In recent years, the amount of high-strength concrete and sprayed concrete in which silica fume is used has been increasing due to the increase in the number of structures and tunnel construction. When silica fume is blended with these concretes, silica fume is often blended directly in powder form. However, in this case, the silica fume is extremely bulky with a bulk density of about 0.2 to 0.3, so that it is difficult to carry out mass transportation at one time, and dust is easily generated at the time of operation, and handling is difficult. . Further, silica fume has a problem that it is difficult to be uniformly mixed into the concrete and locally aggregates.

  In order to solve such problems, a method has been proposed in which silica fume is added to a high-concentration silica fume slurry by adding a dispersant, which is a high-performance water reducing agent for concrete or mortar, and water. For example, Patent Document 1 includes a naphthalene sulfonic acid formalin condensate system, a melamine sulfonic acid formalin condensate system, a lignin sulfonate system, a polycarboxylate system, a co-condensate system of naphthalene sulfonic acid and lignin sulfonic acid, Condensed triazines are mentioned.

  Patent Document 2 proposes to lower the viscosity by adding sulfuric acid or carbon dioxide as a pH adjuster and adjusting the pH of the silica fume slurry to 1.0 to 5.8.

Furthermore, Patent Document 3 discloses a dispersant and a pH adjuster in which a copolymer of an aliphatic (unsaturated) sulfonic acid and an unsaturated carboxylic acid, or a combination of polyacrylate and naphthalenesulfonic acid formalin condensate is used. Is used together to obtain a low-viscosity silica fume slurry having a concentration of 40 to 60% by weight.
JP 60-129132 A Japanese Patent No. 2672004 Japanese Patent No. 3451407

  However, since the polycarboxylate-based dispersant is not excellent in the dispersibility of silica fume, the resulting slurry has poor fluidity and is not suitable for the production of a high concentration silica fume slurry exceeding 50% by weight. Naphthalenesulfonic acid formalin condensate salt is excellent in silica fume dispersibility, but when mixed with polycarboxylic acid-based high-performance AE water reducing agent widely used in the production of high-strength concrete, the flowability of fresh concrete In order to add a predetermined fluidity to high-strength concrete, it is necessary to add an excessive amount of polycarboxylic acid-based high-performance AE water reducing agent, delaying the setting of concrete, stagnant strength, etc. Problems occur.

  Also, when improving the fluidity of silica fume slurry by adjusting the pH, depending on the type of acid or the amount added, it may adversely affect the properties of high-strength concrete, such as abnormal condensation, reduced strength, abnormal expansion, and rusting of reinforcing bars. There's a problem.

  Accordingly, the present invention provides a high-concentration silica fume slurry having a high concentration, which maintains good fluidity and does not adversely affect the physical properties of the concrete when blended with concrete. With the goal.

  In order to achieve such an object, as a result of intensive studies, the present inventors have found that a high-concentration silica fume slurry having good fluidity can be obtained by using an appropriate amount of an appropriate dispersant. Was completed.

That is, the present invention
(1) It has at least a water-soluble polymer comprising a copolymer comprising a polymer comprising a monomer containing a carboxyl group and a polymer comprising a monomer containing an amide group and a sulfonic acid group. Dispersant for silica fume slurry;
(2) The silica fume according to (1), wherein the monomer containing the carboxyl group is acrylic acid or methacrylic acid or a salt thereof, and the monomer containing the amide group and the sulfonic acid group is acrylamidomethylsulfonic acid or a salt thereof. Dispersing agent for slurry;
(3) The dispersant for silica fume slurry according to (1) or (2), wherein the monomer containing the amide group and the sulfonic acid group is 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof;
(4) A silica fume slurry containing a dispersant for silica fume slurry having at least a water-soluble polymer mainly composed of polystyrene sulfonic acid or a salt thereof , water, and silica fume, wherein the concentration of the silica fume is 60 Silica fume slurry, wherein the amount of the dispersant for silica fume slurry is 0.5 to 2.0% by weight with respect to the silica fume .
(5) A silica fume slurry comprising the dispersant for a silica fume slurry according to any one of (1) to ( 3 ), water, and silica fume;
(6) The silica fume slurry according to (5), wherein the concentration of the silica fume is 50 to 75% by weight;
(7) The silica fume slurry according to (5) or (6), wherein an addition amount of the dispersant for silica fume slurry is 0.05 to 2.0% by weight with respect to the silica fume;
(8) A method for producing concrete, characterized by being produced using the silica fume slurry according to any one of claims ( 4 ) to (7);
Is to provide.

  ADVANTAGE OF THE INVENTION According to this invention, the high concentration silica fume slurry for cement mixing with favorable fluidity | liquidity can be obtained, avoiding having a bad influence on the physical property of concrete, when it mix | blends with concrete. As a result, it becomes possible to produce concrete suitably while facilitating transportation and handling of the silica fume.

Hereinafter, an embodiment of the present invention will be described.

  The dispersant for silica fume slurry of the present invention is a copolymer comprising a polymer comprising a monomer containing a carboxyl group in the molecule and a polymer comprising a monomer containing an amide group and a sulfonic acid group in the molecule. And / or at least a water-soluble polymer comprising polystyrene sulfonic acid or a salt thereof as a main component.

  Further, the polymer used in the present invention comprises a copolymer comprising a monomer containing a carboxyl group in the molecule and a polymer comprising a monomer containing an amide group and a sulfonic acid group in the molecule. Examples of the water-soluble polymer include acrylic acid-acrylamidomethylsulfonic acid copolymer or a salt thereof, and methacrylic acid-acrylamidomethylsulfonic acid copolymer or a salt thereof. Specifically, examples of the monomer containing an amide group and a sulfonic acid group include 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof, but the present invention is not limited to the monomer, Various things can be adopted.

  On the other hand, examples of the water-soluble polymer composed mainly of polystyrene sulfonic acid or a salt thereof used in the present invention include sodium polystyrene sulfonate, calcium polystyrene sulfonate and the like, but the present invention is not limited thereto. Various things can be adopted.

  And the silica fume slurry which concerns on this invention has the dispersing agent for silica fume slurries mentioned above, a silica fume, and water.

  Here, the silica fume used in the present invention is an ultrafine particle material mainly composed of siliceous material, and is a “silica fume for concrete” defined in JIS A 6207, or of a quality equivalent thereto. As such a silica fume, for example, a by-product of ultrafine particles generated when manufacturing silicon, a silicon-containing alloy, ferrosilicon or the like can be mentioned.

  The concentration of the silica fume slurry in the present invention is preferably 50 to 75% by weight. If the silica fume concentration is less than 50% by weight, the amount of water increases, the transportation cost of the silica fume slurry increases, and the blending amount of the silica fume slurry in the high-strength concrete may be limited. On the other hand, if the silica fume concentration exceeds 75% by weight, the effect of lowering the viscosity of the dispersant is not effective, the viscosity of the silica fume slurry becomes too high, and handling such as stirring and quantitative supply becomes difficult, and the dispersibility of the silica fume is reduced. May be insufficient.

  Addition amount of water-soluble polymer comprising a copolymer comprising a polymer containing a carboxyl group in the molecule and a polymer comprising a monomer containing an amide group and a sulfonic acid group in the molecule Is preferably 0.05 to 2.0% by weight based on silica fume.

  A water-soluble polymer comprising a copolymer comprising a monomer containing a carboxyl group in the molecule as a dispersant and a polymer comprising a monomer containing an amide group and a sulfonic acid group in the molecule. If the addition amount is too small, there is a possibility that a silica fume slurry having a sufficiently reduced viscosity cannot be obtained, and if it is too much, the strength expression of the blended concrete may be insufficient.

  On the other hand, it is preferable that the addition amount of the water-soluble polymer having polystyrene sulfonic acid or a salt thereof as a main component is 0.05 to 2.0% by weight with respect to silica fume.

  If the amount of the water-soluble polymer mainly composed of polystyrene sulfonic acid or a salt thereof as a dispersant is too small, there is a possibility that a silica fume slurry having a sufficiently reduced viscosity cannot be obtained. May be insufficient.

  And the manufacturing method of the concrete which concerns on this invention uses the above-mentioned silica fume slurry, It is characterized by the above-mentioned. Specifically, the mixing amount of the silica fume slurry of the present invention in the cement composition is appropriately determined according to the cement composition such as concrete to be used, but basically the cement composition such as concrete to be used. What is necessary is just the quantity which gives quality, such as desired workability, intensity | strength, and durability, to a thing. For example, in the case of a silica fume slurry having a concentration of 60% by weight with respect to the cement weight usually contained in the cement composition, it is appropriate to mix the slurry in a proportion of 5 to 30% by weight.

  Hereinafter, the aspect which manufactures the silica fume slurry which concerns on this invention is explained in full detail.

  The method for producing a silica fume slurry of the present invention comprises silica fume, water and a polymer comprising a monomer containing a carboxyl group in the molecule, and a polymer comprising a monomer containing an amide group and a sulfonic acid group in the molecule. If the water-soluble polymer which consists of a copolymer and / or the water-soluble polymer which consists of polystyrene sulfonic acid or its salt as a main component can be mixed uniformly, it will not be restrict | limited.

  Usually, it is a preferable method for obtaining the silica fume slurry of the present invention to dissolve the above-mentioned water-soluble polymer in water and disperse it while adding silica fume little by little while stirring at high speed.

  The silica fume slurry of the present invention thus produced is stored in a storage tank until use or transportation. The silica fume slurry of the present invention preferably retains the fluidity of the slurry by subjecting it to continuous mechanical forced agitation during storage.

  Continuous mechanical forced stirring means that mechanical forced stirring is performed continuously or intermittently, but low-speed continuous stirring or high-speed intermittent stirring is preferable from the viewpoint of reducing power consumption.

  The mechanical stirrer is not particularly limited as long as it has a general rotational speed for high viscosity = 5 to 300 rpm and a rated torque = 0.5 N · m, and the capacity of the silica fume slurry to be manufactured is not limited. In addition, an output or the like is selected. The agitating blade can be any of an edged turbine blade, a propeller blade, a turbine blade, a paddle blade, an anchor blade, a ribbon blade, etc. If it can hold | maintain, an inexpensive and simple apparatus is preferable.

  Although the embodiment of the present invention has been described above, the specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The present invention will be described in more detail with reference to examples of the present invention. However, the present invention is not limited to the examples.

(1) Viscosity measurement test of silica fume slurry The silica fume slurries according to Example 1-1, Example 2-1, Comparative example 1-1, and Comparative example 2-1 were manufactured, and the viscosity was measured.

[Materials used]
Water: Tap water Silica fume: 940-U (Elchem Japan)
Dispersant 1: A-6017 (water-soluble polymer comprising a copolymer comprising a polymer comprising a monomer containing a carboxyl group and a polymer comprising a monomer containing an amide group and a sulfone group: Toa Gosei Co., Ltd.)
Dispersant 2: Polyty PS-1900 (Polystyrene sulfonate: Lion Corporation)
Dispersant 3: Mighty 150 (Naphthalenesulfonic acid formalin condensate water reducing agent: Kao Corporation)
[Test method]
7940 g of tap water was placed in a cylindrical 30 liter polyethylene container at a constant temperature of 20 ° C., 60 g of Dispersant 1, Dispersant 2, and Dispersant 3 were added and dissolved. It was added little by little and stirred for 5 minutes to obtain a silica fume slurry having a concentration of 60% by weight. Among such silica fume slurries, those using Dispersant 1 were Example 1-1, those using Dispersant 2 were Example 2-1 and those using Dispersant 3 were Comparative Example 1-1. .
As a control, a mixture of water and silica fume produced from the above method without using a dispersant was used as Comparative Example 2-1.
And the viscosity of the obtained slurry was measured using the B-type viscosity meter (B-8L: Tokyo Keiki Co., Ltd.).

  Table 1 shows the viscosity measurement results of the silica fume slurry.

In Example 1-1 and Example 2-1, the viscosity is significantly lower than that of Comparative Example 2-1 in which no dispersant is added, and compared with Comparative Example 1-1, which is a conventional dispersant. Also showed the same or better dispersion performance.
(2) Comparison test of interaction with polycarboxylic acid-based high-performance AE water reducing agent.

Example 1-1, Example 2-1, Comparative Example 1-1 and Comparative Example 2-1 Silica fume slurry or a mixture of silica fume and water, kneaded water, cement, sand, polycarboxylic acid-based high performance A cement mortar mixed with silica fume was prepared by adding and stirring each AE water reducing agent.
And each obtained mortar was set to Example 1-2, Example 2-2, Comparative Example 1-2, and Comparative Example 2-2, respectively, and the slump flow was measured.

[Materials used]
Materials other than Example 1-1, Example 2-1, Comparative Example 1-1, and Comparative Example 2-1 are shown below.
Mixing water: Tap water Cement: Low heat Portland cement (Beta L: Sumitomo Osaka Cement)
Sand: Yasu river sand high-performance AE water reducing agent: Seakament 1200N (Nihon Seika)
[Test method]
Table 2 shows the blending ratio of mortar.

In the silica fume slurry according to Example 1-1, Example 2-1, Comparative example 1-1, and Comparative example 2-1, water, cement, sand, and high-performance AE water reduction based on the blending ratio shown in Table 2 The agent was mixed.
Specifically, to the silica fume slurry according to Example 1-1, Example 2-1, Comparative Example 1-1, and Comparative Example 2-1, water excluding high-performance AE water reducing agent, that is, kneaded water is added. After that, cement and sand were mixed. And after stirring for 30 seconds, the high performance AE water reducing agent was thrown in. Thereafter, the mixture was stirred with a Hobart mixer at a low speed for 300 seconds and further at a high speed for 300 seconds.
As described above, the mortar prepared in this manner was obtained by using Example 1-1, Example 1-2, and Example 2-1 using Example 1-1. Example 2-2, Comparative Example 1-1 The one employing Comparative Example 2-2 and the one employing Comparative Example 2-1 were referred to as Comparative Example 2-2. The slump flow was measured.
And the slump flow of Example 1-2, Example 2-2, Comparative Example 1-2, and Comparative Example 2-2 which are the obtained mortar was measured based on the method defined in JIS A 1150.

[Test results]
Table 3 shows the slump flow of each mortar.

  In Comparative Example 1-2, a result with a low slump flow was obtained as compared with Comparative Example 2-2 in which no dispersant was added. Such a cause is considered to be due to the combined use of a polycarboxylic acid-based high-performance AE water reducing agent and a conventional dispersant, naphthalenesulfonic acid formalin condensate water reducing agent.

  On the other hand, in Example 1-2 and Example 2-2, the result that a slump flow became high compared with the comparative example 2-2 which does not add a dispersing agent was obtained. Particularly in Comparative Example 1-1, a particularly high slump flow was obtained.

  From the above two tests, it was found that the silica fume slurry dispersant according to the example of the present invention can obtain a silica fume slurry having a low viscosity, that is, good fluidity. Further, it has been found that such a silica fume slurry can effectively avoid adversely affecting the physical properties of the concrete, that is, reducing the slump flow when blended with concrete.

Claims (8)

For silica fume slurry, comprising at least a water-soluble polymer comprising a copolymer comprising a polymer comprising a monomer containing a carboxyl group and a polymer comprising a monomer containing an amide group and a sulfonic acid group Dispersant. The dispersion for a silica fume slurry according to claim 1, wherein the monomer containing the carboxyl group is acrylic acid or methacrylic acid or a salt thereof, and the monomer containing the amide group and the sulfonic acid group is acrylamidomethylsulfonic acid or a salt thereof. Agent. The dispersant for a silica fume slurry according to claim 1 or 2, wherein the monomer containing the amide group and the sulfonic acid group is 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof. A silica fume slurry containing a dispersant for silica fume slurry having at least a water-soluble polymer mainly composed of polystyrene sulfonic acid or a salt thereof , water, and silica fume,
The silica fume slurry is characterized in that the concentration of the silica fume is 60 to 75% by weight, and the addition amount of the dispersant for silica fume slurry is 0.5 to 2.0% by weight with respect to the silica fume . A silica fume slurry comprising the dispersant for silica fume slurry according to any one of claims 1 to 3 , water, and silica fume. The silica fume slurry according to claim 5, wherein the concentration of the silica fume is 50 to 75% by weight. The silica fume slurry according to claim 5 or 6, wherein an addition amount of the dispersant for silica fume slurry is 0.05 to 2.0% by weight with respect to the silica fume. It manufactures using the silica fume slurry in any one of Claim 4 thru | or 7, The manufacturing method of the concrete characterized by the above-mentioned.