JPH1087362A - Repairing method by filling for concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of dust and to obtain a structure having resis tance against fire by mixing a kneaded material containing a blast furnace granulated slug, ultrafine powder material, dispersant and water with an alkali stimulant to prepare a filling material for repair just before use and then filling a part to be repaired with the filling material. SOLUTION: A blast furnace pulverized slug(WS) having 3000 to 15000cm<3> /g Braine specific surface area is used. The average particle size of the ultrafine powder(UM) used is 0.01 to 0.5μm and silica fume is preferable. The dispersant(SA) is a polymer having carboxylic groups in the molecule and having 1000 to 200000mol.wt. For example, a polyacrylic acid is used. As for the alkali stimulant(AS), various kinds of alkali materials can be used, and for example, sodium hydroxide is preferable. The amt. of UM used is 2 to 50wt.% of the sum amt. of WS and UM. Each amt. of SA and AS used is 0.1 to 10 pts.wt. to 100 pts.wt. of the sum of WS and UM. The amt. of water is determined such a degree that the kneaded material shows a clay or paste state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for filling and repairing gaps and cracks in a concrete structure.

[0002]

BACKGROUND OF THE INVENTION Although concrete is an inexpensive and durable material, it will crack over time. Once cracks occur, water, carbon dioxide gas, etc. penetrate into that area,
Deterioration becomes more severe, cracks become larger, and it cannot be used. Such a phenomenon appears even in ordinary concrete, but in concrete applied with an inappropriate composition, cracks are generated earlier and the degree of cracking becomes large. Cracked concrete structures had been scrap-and-built several years ago, when the economy was good, and they were demolished and rebuilt, but recently they have been carefully repaired and used. In the situation. In addition, concrete structures that have collapsed due to the earthquake must be rebuilt, but those that have been damaged by cracks must be repaired and used.

There are two types of crack repair materials for concrete structures: an organic repair material represented by an epoxy resin, and a polymer cement mortar repair agent obtained by adding a polymer such as SBR or polyvinyl acetate to cement mortar. Mainly used. The former organic repair materials have the advantage that they have good adhesion to concrete and can be injected into very narrow cracks of 0.05 mm or less, but they are expensive and, moreover, are organic polymers. Therefore, it has the drawbacks that it is deteriorated with time and is also vulnerable to fire such as fire. In addition, polymer cement mortar repair materials are not as good as organic repair materials but can be injected into relatively narrow cracks and have good adhesion to concrete, but they are added to improve adhesion. Since the amount of the polymer is as large as 10 to 20% with respect to the cement mortar, there is a problem that the adhesion is extremely reduced in the event of a fire. In addition, polymer cement mortar is mainly made of cement, so it starts to harden when water is added, so it cannot take the form of a liquid product such as an organic repair material. There was a problem that measures had to be taken.

[0004]

For this reason, it is a liquid like a polymer cement mortar, which is powdery and does not generate dust when used, and most of its constituents are inorganic substances, and are filled with fire. There has been a demand for a method for repairing gaps and cracks in concrete structures using a repair agent.

[0005]

Means for Solving the Problems The present inventors diligently studied to solve the above-mentioned problems and completed the present invention. That is, the present invention relates to (1) granulated blast furnace slag, ultrafine powdery substance,
Dispersant, a kneaded material containing water and an alkali stimulant, or an aqueous solution thereof, a gap in a concrete structure characterized by filling the repaired part with a filling repair material obtained by mixing immediately before use, or (2) The filling and repairing method according to the above (1), wherein the kneaded material is in the form of a clay or a paste, and (3) the kneaded material is not cured for at least one week after kneading. (1) The method of (1) or (2), wherein the repaired part is pretreated with water before filling the repaired part with the repaired material. ), And the filling repair method according to any one of (3), (5) the filling method according to (4), wherein an aqueous alkaline stimulant solution and / or a diluted aqueous dispersion of the filling repair material is used instead of water. Repair method.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The granulated blast furnace slag used in the present invention has a Blaine specific surface area of 3,000 to 15,000 cm ² / g, preferably 4,000 to 15,000 cm ² / g or more.

[0008] The ultrafine powdery substance used in the present invention is preferably one or more orders of magnitude smaller than the average particle size of the granulated blast furnace slag, and more preferably two or more orders of magnitude smaller. The preferred average particle size of the ultrafine powder is 1 μm or less,
0.01 to 0.5 μm is more preferable. Specific examples of the ultrafine powdery substance that can be used include, for example, silica fume, fly ash, silica powder, clay, talc, kaolin, aerosil, slowly cooled slag powder, titania, zirconia, silica, alumina, ceramic powder, and the like. Considering the fluidity when prepared as a filling repair material and the adhesive strength to concrete, silica fume is most preferred. The amount of the ultra-fine powdered substance varies depending on the particle size of the granulated blast furnace slag and the type and amount of other various additives to be added as necessary.
Usually, the proportion occupies 2 to 50% by weight, preferably 5 to 30% by weight, more preferably 7 to 20% by weight, based on the total amount of the granulated blast furnace slag and the ultrafine powdery substance.

As the dispersant, a polymer having a carboxylic acid group or a salt thereof in the molecule is preferable. Specifically, poly (meth) acrylic acid, (meth) acrylic acid / maleic anhydride copolymer, ( (Meth) acrylic acid / maleic acid / vinyl ether copolymer, (meth) acrylic acid / itaconic acid / styrene copolymer, maleic anhydride / C5-C8 olefin copolymer, and salts of these polymers are mentioned. I can do it. Here, (meth) acrylic acid refers to acrylic acid or methacrylic acid.

In the above, specific examples of the C ₅ -C ₈ olefin include 2-methylbutene-1, pentene-1, hexene-1, cyclopentene, cyclohexene and the like. In the above description, examples of the salt include alkali metal salts such as lithium, sodium, and potassium, and ammonium salts can also be used.

Further, the dispersant may be a copolymer of a monomer copolymerizable with (meth) acrylic acid, maleic anhydride, itaconic acid, styrene, vinyl ether and the like. Examples of copolymerizable monomers include hydroxyethyl (meth) acrylate, N-vinylpyrrolidone, sodium styrene sulfonate, sodium (meth) allyl sulfonate, vinyl acetate, methyl (meth) acrylate, and (meth) acrylic acid. Ethyl, butyl (meth) acrylate),
Acrylonitrile, (meth) acrylamide, ethylene, propylene, isobutylene and the like can be mentioned.

Further, the dispersing agent used in the present invention is not limited to the dispersing agents mentioned here, and is, for example, a salt of a formalin condensate of naphthalenesulfonic acid, which is known as a water reducing agent for cement and concrete. Lignin sulfonic acid salts, melamine sulfonic acid salts, and the like can be used, and these can be used in combination with the above-mentioned dispersants. When used in combination, the proportion of these water reducing agents in the total dispersant is preferably 50% or less.

The molecular weight of the dispersant is 1,000 to 200,0.
00 can be used, but 3,000-100,000
It is preferred to use

The amount of the dispersant used is usually 0.1 to 100 parts by weight of the total amount of the granulated blast furnace slag and the ultrafine substance.
It is 1 to 10 parts by weight, preferably 0.3 to 6 parts by weight, more preferably 0.5 to 4 parts by weight.

The amount of water used in the present invention depends on the particle size of the granulated blast furnace slag, the type and amount of ultrafine powdery substance, the type and amount of dispersant used, and the type of fine aggregate to be added if necessary. It is preferably used to such an extent that the kneaded material is in the form of a clay or paste, and is generally 1 to 100 parts by weight of the total amount of granulated blast furnace slag and ultrafine powdery substance.
0 to 40 parts by weight, preferably 15 to 30 parts by weight, more preferably 18 to 25 parts by weight. In addition, when an alkali stimulant is added as an aqueous solution as described below, the amount of water used is such that the total amount of water in preparing the kneaded material with water in the aqueous alkali stimulant solution is within the above range. Is preferred.

The kneaded material may contain cement, if necessary.
Fine aggregate used in mortar can be added, but it is preferable to use a fine particle having a small particle size in view of the properties as a filling and repairing agent. Specifically, the average particle diameter is 100 μm or less, preferably 50 μm or less, more preferably 20 μm or less.
The following fine aggregate is used. Further, an inert ultrafine powdery substance among the above ultrafine powdery substances may be used. When these fine aggregates are used, the amount of the fine aggregates to be used is about 20 to about 100 parts by weight in total of the granulated blast furnace slag and the ultrafine powdery substance.
It is 150 parts by weight.

As the alkaline stimulant that can be used in the present invention, various alkaline substances can be used. Specific examples of the alkali stimulant include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; carbonates of alkali metals such as sodium carbonate, sodium carbonate, and potassium carbonate; and calcium hydroxide. Alkaline earth metal hydroxides such as sodium hydroxide, magnesium hydroxide, etc., and alkali metal silicates such as sodium (meth) silicate, potassium (meth) silicate, sodium (ortho) silicate, and water glass. Among these curing stimulants, hydroxides of alkali metals are preferred, and among them, the use of sodium hydroxide is particularly preferred.

The amount of the alkali stimulant used depends on the particle size of the granulated blast furnace slag, the type and amount of the ultrafine powdery material, the type and amount of the dispersant used, and the type of fine aggregate added if necessary. The amount varies depending on the amount, etc., but generally 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the total amount of the granulated blast furnace slag and the ultrafine powdery substance.
1 to 3 parts by weight. Further, it is preferable to use an amount such that the concentration of the aqueous alkali stimulant solution in the filling repair material is 4 to 10% by weight. The alkali stimulant may be added to and mixed with the kneaded material as it is, but is preferably added and mixed as an aqueous solution.

Next, a method for producing a filling repair material used in the present invention will be described. A predetermined amount of granulated blast furnace slag, ultrafine powdery substance, dispersant, water, and fine aggregate as an optional component are measured into a mixer and kneaded. As the kneader, an oscillating omni mixer or a planetary mixer or an Erich-type kneader to which a shearing force can be applied can be used. The kneading time varies depending on the amount of water to be added and the amount of dispersant, but is generally 5 to 30 minutes.

The kneaded product thus obtained is in the form of a paste or clay, and surprisingly,
1 month or more in a preferable state, 3 in a more preferable state
Since it does not cure for more than one month, it can be used like a two-part epoxy repair material in combination with an aqueous alkali stimulant solution.

Hereinafter, the filling repair method of the present invention will be described. In the filling / repairing method of the present invention, a prescribed amount of the kneaded material and a prescribed amount of the alkali stimulant or the aqueous solution of the alkaline stimulant are measured and mixed immediately before the repairing operation to prepare and use a filling / repair material. Mixing is completed with a simple propeller-type stirrer and a uniform liquid repair material is obtained.

As a method of injecting the above-mentioned filling and repairing agent into a gap or a crack portion of a concrete structure, a natural injecting method or a pouring method in which the agent is naturally infused, or a press injecting method using a caulking gun or the like under pressure. Method, etc. can be adopted.

When the filling material used in the present invention is injected into a gap or a crack in a concrete structure, these repaired parts are usually dried in an air-dry state. Preferably, the injection site is moistened with water prior to injection.

Further, in the embodiment of the present invention, the area to be filled and repaired is reduced by using an aqueous solution of an alkali stimulant and / or a diluted aqueous dispersion of the filling repair material instead of the above-mentioned water, thereby narrowing the area to be filled and repaired. A filling repair agent can be injected into the crack. For example, if no pre-treatment was performed and only the cracks having a width of about 0.5 mm could be injected, the pre-treatment as described above could be performed to inject a crack of about 0.1 mm. become able to do.

[0025]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

<Production Examples of Kneaded Materials for Filling and Repairing Materials> Production Examples 1 to 5 Materials of the types and amounts (parts by weight) shown in Table 1 were weighed into an omni mixer, and powder mixing was performed for 5 minutes. Next, the dispersant and water of the kind and amount shown in Table 1 were added and kneaded for 15 minutes to obtain a clay-like or paste-like kneaded material.

[0027]

[Table 1] Table 1 Production Example 1 Production Example 2 Production Example 3 Production Example 4 Production Example 5 Granulated blast furnace slag (A) 90 (A) 87 (D) 90 (F) 80 (A) 90 Ultra fine powdery substance (B) 10 (B) 13 (B) 10 (B) 20 (B) 1 Fine aggregate − − (E) 50 (E) 40 − Dispersant (C) 2 (C) 2 (C) 2 (G ) 2 (C) 2 Water 16.5 20.8 21.2 23.7 21.5 Appearance of kneaded material Paste Paste Clay Paste Paste (Note) (A); Specific surface area 4,000 cm ² / g granulated blast furnace slag (D); granulated blast furnace slag with a specific surface area of 10,000 cm ² / g (F); granulated blast furnace slag with a specific surface area of 6,000 cm ² / g (B); average particle size 0.15 μm of silica fume (E); slowly cooled ferro chromium slag 8 No. (C); C ₄ ~C ₆ chain olefin copolymer water-soluble salts and naphthalene sulfonate soda Holm of ethylenically unsaturated dicarboxylic acid anhydride Mixture of aldehyde condensate (Nippon Zeon Co., Ltd., work 500S) (G); sodium naphthalene sulfonate formaldehyde condensate (Kao Co., Ltd., Mighty 2,000)

Examples 1 to 5 A test piece (concrete) of 4 cm × 4 cm × 16 cm was bisected in the vertical direction to obtain 2 cm × 4 cm × 16 cm. One end of the two sheets in the long side direction was brought into contact with each other, the other side was opened with a width of 1 mm, and the side face was sealed with tape to obtain a test piece for measuring the injection width of the filling material. (See FIG. 1) Next, 25% caustic soda aqueous solution (Example 1; 5.1 parts by weight, Example 2; 6.2 parts by weight) with respect to 100 parts by weight of the kneaded material shown in Production Examples 1 to 5 , Example 3; 4.5 parts by weight, Example 4; 4.5 parts by weight, Example 5; 6 parts by weight) and mixed to obtain a filling repair material used in the present invention. The filling material thus obtained was injected from the side of the specimen having a width of 1 mm, then cured at 90 ° C. for 24 hours to cure the filling material, and the width direction in which the filling material was injected The specimen was cut in a direction perpendicular to the above (see FIG. 2), and the injection width of the filling repair material was measured by a comparator (unit: mm). Table 2 shows the results
Shown in The injection was performed by natural injection. The conditions of the injection width test specimens were the surface dry state, the surface wet with water, the surface wet with a 3% aqueous solution of caustic soda, and the solid content of the repair material using the surface was 1/5.
What was wet with the aqueous dispersion of the filling repair material was used.

[0029]

Table 2 Example 1 2 3 4 5 Kneaded material used for filling and repairing material Manufacturing Example 1 Manufacturing Example 2 Manufacturing Example 3 Manufacturing Example 4 Manufacturing Example 5 Fluidity of filling and repairing material (flow value, mm) 400 420 360 380 480 Injection width (mm) Injection width measurement Specimen condition (a) Surface dry 0.28 0.31 0.76 0.51 0.35 (b) Water wet 0.11 0.09 0.45 0.43 0.15 (c) Wet with 3% Na0H 0.12 0.48 (d) Wet with 1/5 concentration of repair material 0.20 0.15 0.57 0.14

Examples 6 to 10 The 4 cm × 4 cm × 16 cm concrete test specimens used in Examples 1 to 5 were subjected to a bending test of two equally-divided two-point loadings with a span of 15 cm and a loading point width of 5 cm. The interval between the two test pieces (surface dry state) after the test was set to 0.8 mm, during which a filling and repairing material having the same composition as that used in Examples 1 to 5 was injected, and 20 ° C. × The flexural strength after curing for 28 days was measured. Table 3 shows the results. The kneaded material of the filling repair material was prepared as shown in Table 3 below.
Used after the number of days indicated in (1). The bending test result of the concrete specimen itself is 50-60 kgf / cm.
^{Was 2} .

[0031]

Table 3 Example 6 7 8 9 10 Kneaded material used for filling and repairing material Production Example 1 Production Example 2 Production Example 3 Production Example 4 Production Example 5 Age of kneaded material 7 28 28 14 28 After filling and repair Bending strength 69 73 51 48 53 (Kgf / cm ² ) Fracture point Repair surface Repair surface Repair surface Repair surface Repair surface Other than other than Other than other than repair surface

Examples 11 to 15 The injection part of the concrete specimen was treated with 4% Na as a pretreatment.
The same operations as in Examples 6 to 10 were performed except that the OH solution was wetted with an aqueous OH solution or an aqueous dispersion of a filling repair material diluted with water to a solid concentration of 1/4. Table 4 shows the results.

Table 4 Example 11 12 13 14 15 Pretreatment Presence or Absence 4% NaOH ○ 1 水 Aqueous dispersion of filler material at 1/4 concentration ○ ○ Bending strength after filling repair 67 68 55 50 57 (Kgf / cm ² ) Fracture point Repair surface Repair surface Repair surface Repair surface Repair surface Other than Other than Other than Other

Example 16 A large number of fine cracks occur and leaks after construction 2
An aqueous dispersion of the filling repair material obtained by diluting the filling repair material used in Example 5 with water so as to have a solid content concentration of 1/5 was press-fitted into a cracked portion of the 5-year concrete with a caulking gun. After confirming that the aqueous dispersion overflowed from the cracked portion, the filling and repairing material was similarly injected with a caulking gun. Two weeks after the injection, it rained, but no leakage occurred, confirming that the concrete was filled and repaired. One month later, a part including the cracked portion that was filled and repaired was cut out, and the minimum injection width of the filling and repairing material was measured to be 0.07 mm. In addition, when a bending test was performed on a 4 cm × 4 cm × 16 cm concrete specimen including the filled and repaired portion, the fractured portion was not the filled and repaired portion but the original concrete portion.

Reference Example The repair material used in Example 1 was poured into a box-shaped formwork of 4 cm × 4 cm × 1 cm, demolded three days later, and at room temperature and 90% humidity.
After curing in the above humid atmosphere for 28 days, it was dried to a surface-dry state. Five sheets made of the cured material of the repair material thus obtained are stacked, tied with a wire, and 4 cm × 4 cm × 5 cm
Block. This block is placed in an electric furnace set at 750 ° C. for measurement of a base material test for a nonflammability test of a building material,
As a result of measuring the temperature rise for 20 minutes, the maximum temperature was 796
° C, and this filled repair material was found to be equivalent to the non-combustible material in building materials.

[0036]

According to the filling and repairing method of the present invention, an inorganic stimulant or an aqueous solution of an alkali stimulant is added to and mixed with a clay-like or paste-like kneaded material immediately before use while being an inorganic (ceramic) material. This has the effect of filling and repairing cracks in concrete.

[Brief description of the drawings]

FIG. 1 Specimen 1 used in Examples 1 to 5; Specimen for injection width measurement 1a; 2 cm × 4 cm × 16 cm 2; 1 mm width

FIG. 2 shows a test specimen after curing and curing 3; shows a cut surface 4; a filling repair material after injection curing

Claims (5)

[Claims] 1. Granulated blast furnace slag, ultrafine powdery substance, dispersant,
A gap in a concrete structure characterized by filling a repaired part with a filling repair material obtained by mixing a kneaded material containing water and an alkali stimulant, or an aqueous solution thereof immediately before use,
Or a method for filling and repairing cracks. 2. The method according to claim 1, wherein the kneaded material is in the form of a clay or a paste. 3. The method according to claim 1, wherein the kneaded material is not cured for at least one week after kneading. 4. The repaired portion is pretreated with water before filling the repaired material with the repaired portion.
4. The filling repair method according to any one of items 2 and 3. 5. An aqueous alkaline stimulant solution and / or a diluted aqueous dispersion of a filling repair material is used in place of water.
The filling repair method described.