JP5095202B2 - Repair material for cross-section defects in concrete structures - Google Patents

Description

  The present invention relates to a restoration material used for repairing a cross-sectional defect of a concrete structure such as a building.

Concrete structures may have partial defects in concrete due to initial defects such as jumpers, salt damage, deterioration such as neutralization, and damage such as collisions. Or, it is often not preferable from the viewpoint of durability, aesthetics, and the like.
Conventionally, cement mortar, polymer cement mortar, and the like are generally used as a method for repairing such partial and small-scale defects. As these materials, cement, aggregate, various admixtures / admixtures, etc. are prepared on site, or premixed mortar in which powders other than water are preliminarily prepared is used.

  However, it is necessary to mix these materials and water at the construction site, and it takes time and effort to prepare the mixing equipment, weigh the water, and wash the mixing equipment. Had.

  By the way, in the repair method of the crack part of concrete, in order to improve the effort regarding mixing in a construction site, dust generation, etc., the particle gap containing Portland cement and / or mixed cement and calcium aluminate is 45 to 45. It is disclosed that a fluid curing material containing 65% by volume of mixed particles and an organic solvent having a solubility parameter of 9.0 or more and having a viscosity at 20 ° C. of 20 Pa · s or less is disclosed.

  However, when this fluid hardening material is used for repairing a cross-sectional defect of a concrete structure as described above, the viscosity is low, so that it sags and there is no filling property to the cross-sectional defect and cannot be used at all. .

JP-A-2005-314140

  The present invention is a restoration material used for repairing a cross-sectional defect of a concrete structure, which does not require on-site measurement and mixing operation, and is excellent in a cross-sectional defect part of a concrete structure without sagging in a repair operation. An object of the present invention is to provide a restoration material that can be filled and cured by spraying water to develop strength.

As a result of intensive studies, the present inventors have premixed cement, fine aggregate, a water-soluble organic solvent having a specific boiling range, and a thickener, and the viscosity at 20 ° C. is within a specific range. The present inventors have found that a gel-like restoration material can achieve the above-mentioned object.
That is, the present invention
(1) Cement, a fine aggregate, all or part of which is a lightweight fine aggregate, a water-soluble organic solvent having a boiling point of 30 to 100 ° C., and a thickener, and a viscosity at 20 ° C. A repair material for a cross-sectional defect of a concrete structure, characterized in that is more than 500 Pa · s and not more than 3000 Pa · s;
(2) Unit cement amount 500 to 1200 g / l, 50 to 300 parts by volume of fine aggregate with respect to 100 parts by volume of cement, water-soluble organic solvent having a boiling point of 30 to 100 ° C. to total amount of cement and fine aggregate 25 to 55% by mass of the above, and the above-mentioned (1) concrete structure cross-sectional defect repairing material containing a thickening material;
(3) A repair method for cross-sectional defects of a concrete structure, characterized in that the repaired material of the above (1) or (2) is filled in the cleaned repair target part and sprayed with water;
Is to provide.

  The restoration material for a defect in a cross section of a concrete structure according to the present invention is a gel-like restoration material obtained by premixing cement, a fine aggregate whose whole or part is a lightweight fine aggregate, a water-soluble organic solvent, and a thickening material. No on-site weighing and mixing operations are required and no dust is generated. And, the gel-like restoration material of the present invention does not sag at the time of repairing work (because light fine aggregate is an essential component as a fine aggregate, it has excellent non-sag characteristics and may sag even when the repair location is large It is possible to fill the cross-sectional defect part of the concrete structure well, and by spraying water, the sprayed water replaces the water-soluble organic solvent, and the water-soluble organic solvent evaporates. The reaction occurs / accelerates and hardens to develop strength. Moreover, since the restoration | restoration material of this invention does not contain water, it does not harden | cure over a long period of time at the time of storage, and since it is a suitable viscosity, it does not isolate | separate but favorable workability | operativity is ensured.

  The restoration material for a cross-sectional defect of a concrete structure according to the present invention comprises cement, a fine aggregate whose whole or part is a lightweight fine aggregate, a water-soluble organic solvent having a specific boiling range, and a thickening material. It is a premixed gel-like restoration material with a specific viscosity range.

Cement used in the present invention includes ordinary Portland cement, early-strength Portland cement, ultra-early strong Portland cement, moderately hot Portland cement, sulfate-resistant Portland cement and other Portland cements; and blast furnace cement, silica cement, fly ash cement and the like In addition, as a super-hard cement, for example, a so-called jet cement mainly composed of 11 (CaO) ₇ (Al ₂ O ₃ ) CaF ₂ ; three components of Portland cement, alumina cement and gypsum An ultra-fast hard cement composed of: alumina cement alone can be used.
In the present invention, since the hydration of the cement is delayed due to the presence of the water-soluble organic solvent, it is preferable to use a super-hard cement, and the setting time (end time) measured according to JIS R5201 is about 1 to 60 minutes. It is preferable that it is a super fast hardening cement. Further, in order to adjust the setting time, it is preferable to use a combination of hardening accelerators such as sodium carbonate, potassium carbonate, lithium carbonate, sodium hydrogen carbonate, lithium sulfate, triethanolamine and calcium formate to accelerate cement hydration. .
The amount of cement used in the restoration material of the present invention is preferably 500 to 1200 g / l, more preferably 600 to 1000 g / l, and particularly preferably 700 to 1000 g / l as a unit cement amount. Is desirable.

All or part of the fine aggregate used in the restoration material of the present invention is a lightweight fine aggregate.
Light-weight fine aggregates are fine aggregates with an absolute dry density of less than 2.3. These light-weight fine aggregates are artificial lightweight fine aggregates mainly composed of expanded shale, expanded clay, expanded slate, fly ash, etc. (Absolutely dry density less than 1.3), natural lightweight fine aggregates such as volcanic rubble (absolutely dry density 1.3 to less than 1.8), by-product lightweight fine aggregates such as expanded slag (absolutely dry density 1. 8 or more and less than 2.3).
As a concrete commercial product of the artificial lightweight fine aggregate, square “mesalite” (trade name, manufactured by Nihon Mesalite Industry Co., Ltd., main component: expanded shale) manufactured by firing pulverized shale, “ Asanolite "(trade name, manufactured by Taiheiyo Material Co., Ltd., main component: expanded shale)," Fuolite "(trade name, manufactured by Sakai Perlite Co., Ltd., main component: obsidian), and the like.
Moreover, the maximum particle size of the lightweight fine aggregate used in the present invention is preferably 6 mm or less, and the average particle size of the fine aggregate is preferably 0.1 mm to 2.5 mm.

In the present invention, ordinary fine aggregates having an absolute dry density of about 2.4 to 3.0 can be used together with lightweight fine aggregates.
As ordinary fine aggregates, river sand, sea sand, mountain sand, crushed sand, No. 3-8 silica sand, limestone, slag aggregate, etc. can be used. It is preferable to use a fine aggregate such as limestone, and it is preferable to use a dry fine aggregate. Further, it is preferable that the ordinary fine aggregate has a maximum particle size of 6 mm or less and the average particle size of the fine aggregate is 0.1 mm to 2.5 mm.

In the restorative material of the present invention, the blending ratio of the fine aggregate, all or part of which is a lightweight fine aggregate, is preferably 50 to 300 parts by volume, more preferably 80 to 300 parts by volume with respect to 100 parts by volume of cement. It is desirable that the volume is 250 parts by volume, particularly preferably 100 to 200 parts by volume.
When ordinary fine aggregates are used in combination with lightweight fine aggregates, the volume ratio of the lightweight fine aggregates: ordinary fine aggregates is preferably 95: 5 to 30:70, and 95: 5 It is more preferable that it is 50:50, and it is further more preferable that it is 95: 5-65: 35. By using ordinary fine aggregate in combination with such a volume ratio, it is possible to improve the replaceability between spray water and water-soluble organic solvent with almost no deterioration of droop due to the increase in specific gravity of the fine aggregate. Time is shortened.

The organic solvent used in the present invention is water-soluble and has a boiling point of 30 to 100 ° C. During the restoration work, since the spray water reacts with the cement, the organic solvent must be water-soluble so that the spray water and the organic solvent are mixed and replaced, and the hydration reaction between the cement and water proceeds. And in order for hardening to progress, it is required that a boiling point is 30-100 degreeC so that an organic solvent evaporates rapidly, and it is more preferable that a boiling point is 30-80 degreeC.
Examples of the water-soluble organic solvent include lower alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and esters such as ethyl acetate. Ethanol is most preferably used from the viewpoint of influence on the human body.
The blending ratio is preferably 25 to 55% by mass, more preferably 25 to 45% by mass, and particularly preferably 25 to 40% by mass with respect to the total amount of cement and fine aggregate.
If the amount of the water-soluble organic solvent is too small, even if it can be gelled, the viscosity is too high and the filling property and workability are deteriorated. A gap is formed, and it takes time to replace the spray water, and the hydration reaction (hardening reaction) of the cement is slowed.

The gel-like restoration material of the present invention is a cement, fine aggregate, and a water-soluble organic solvent having a boiling point of 30 to 100 ° C., the cement and fine aggregate are settled and the organic solvent is separated to maintain a uniform gel state. Since this is not possible, the thickener is an essential component.
The following can be mentioned as the thickening material suitably used in the present invention.
Organic thickeners such as cellulose water-soluble polymers that are soluble in water-soluble organic solvents such as methylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, hydroxyethylcellulose, and hydroxypropylcellulose; dispersible in water-soluble organic solvents such as smectite Inorganic thickeners such as clay minerals; inorganic fine powders having the ability to prevent cement slurry separation such as calcium carbonate and siliceous fine powders can be used. Among these, organic thickeners such as a cellulose-based water-soluble polymer having a large thickening action are always used, and it is preferable to use other thickening materials such as inorganic thickeners and inorganic fine powders in combination.
The organic thickener which is the main thickener is preferably a cellulose-based water-soluble polymer having a relatively high molecular weight having a 20% viscosity of about 1000 to 4000 mPa · s in a 2% concentration aqueous solution.
The cellulose-based water-soluble polymer that is an organic thickener is usually blended in the range of 0.1 to 5 parts by mass with respect to a total of 100 parts by mass of cement and fine aggregate. Moreover, when using together an inorganic thickener and an inorganic fine powder, in addition to an organic thickener 0.1-5.0 mass part with respect to a total of 100 mass parts of cement and a fine aggregate, an inorganic thickener 0 It is preferable to add in the range of .2 to 3.0 parts by mass and 1.0 to 20.0 parts by mass of the inorganic fine powder.

The viscosity of the gel-like restoration material of the present invention is more than 500 Pa · s at 20 ° C. and less than 3000 Pa · s from the viewpoints of filling property to the cross section of the concrete structure, workability, and separation stability of the restoration material itself. It needs to be. If this viscosity is too low, sagging will occur even if it is filled, and material separation will occur during storage of the restoration material. On the other hand, if the viscosity is too high, it is difficult to fill the defect part without a gap, resulting in a gel with poor workability.
The viscosity can be adjusted by adjusting the amount of the thickening material, or can be adjusted by adjusting the amount of the water-soluble organic solvent.

The gel-like restoration material of the present invention can be preferably further blended with a re-emulsifying powder resin as defined in JIS A6203. Examples of these re-emulsifying powder resins include polyacrylates such as methyl methacrylate / butyl acrylate, styrene / acrylate copolymers, styrene butadiene rubber (SBR), ethylene vinyl acetate (EVA), and vinyl acetate / versaic acid. Examples thereof include resins such as vinyl ester copolymers.
These re-emulsification type powder resins are re-emulsified with sprayed water after the application of the gel-like restoration material, and have the effect of increasing the adhesiveness and adhesion to the cross-section defect of the concrete structure. The use of an acrylic re-emulsifying powder resin is particularly preferred because of excellent durability such as water resistance.
The re-emulsified liquid of the re-emulsified powder resin preferably has a minimum film forming temperature of 0 ° C. or higher. When the minimum film-forming temperature is 0 ° C. or higher, the adhesion to concrete is good, the surface hardness of the restoration material is hard, and the early strength development is excellent.
As a compounding quantity of re-emulsification type powder resin, 0.1-5 mass parts is preferable with respect to a total of 100 mass parts of cement and a fine aggregate.
Furthermore, pigments such as white and black can be added for the purpose of color adjustment with the restoration target portion of the concrete structure.

The present invention provides a method for repairing a cross-section defect in a concrete structure.
That is, the above-described gel-like restoration material is filled into a cleaned restoration target portion and sprayed with water.
Gel of the present invention after the surface of the concrete structure, which is the restoration target, is removed with air or water, and in some cases with a wire brush or the like, the surface is cleaned by removing floating, weak parts, dust, etc. Fill the shape restoration material with a trowel or spatula. Thereafter, water is sprayed on the restoration part by spraying. Spray water and a water-soluble organic solvent having a boiling point of 30 to 100 ° C. are mixed and replaced, the organic solvent evaporates, a hydration reaction between cement and water occurs, and hardening progresses to develop strength. As a result, the cross-sectional defect of the concrete structure is repaired.

  In addition, the gel-like restoration material of the present invention is stored in a closed container such as a plastic tube, a rubber tube, a plastic container, a glass container, or a metal tube after production and used.

Hereinafter, the present invention will be described in more detail with reference to examples of the present invention.
Examples 1-6
(1) Manufacture of gel-like restoration materials [materials used]
Cement: Lion Sisui 105 (Sumitomo Osaka Cement Co., Ltd.)
Lightweight fine aggregate: Fuyolite Special No. 1 (Made by Perlite Co., Ltd.)
Fine aggregate: Silica sand No.6, No.7, No.8 mixed in the same mass (Made by Toki Industries)
Organic solvent: Reagent ethanol 95.5% (manufactured by Kanto Chemical Co., Inc.)
Re-emulsifying powder resin: Mobilis powder DM2072P (manufactured by Nichigo Mobile Vinyl Co., Ltd.)
Water-soluble cellulose: hydroxypropylcellulose HPC-H (manufactured by Nippon Soda Co., Ltd.)
Smectite: Hectorite BENTONE CT (Made by Elementis Japan)
Calcium carbonate: LP200 (Omi Mining Co., Ltd.)
A mixer (Chiyoda Giken Kogyo Co., Ltd .; Omnimixer OMN-15, capacity 15 liters) in which a predetermined amount (unit: part by mass) shown in Table 1 was weighed in a room controlled at a temperature of 20 ° C. and a humidity of 60%. It was put in and mixed for 5 minutes to obtain a gel-like restoration material.

(2) Measurement of physical properties of gel-like restoration material and evaluation of workability, etc. A gel-like restoration material is produced as described above, and its viscosity measurement and material separation evaluation are performed at 5, 10, 20, and 30 ° C., respectively. This was performed as follows using a temperature-controlled bath.
[Measurement of viscosity]
500 cc of the gel-like restoration material sample was placed in a 500 cc beaker, and allowed to stand at a predetermined temperature for 1 day. Then, using a TV-10 viscometer (manufactured by Toki Sangyo Co., Ltd .; TVB-10M), rotor No. 7 was measured at 0.3 rpm or 0.6 rpm.
The results are shown in Table 1.
[Evaluation of material separation]
It was put into a cylindrical container made of transparent glass having a height of 100 mm and φ30 mm and left in a thermostatic bath at each temperature for 7 days, and an evaluation was made based on whether the organic solvent separated and floated on the top.
The results are shown in Table 1.
○: No separation △: Slight separation ×: Separation

Fillability, workability, evaluation of curing conditions, bending strength, compressive strength, and adhesion strength were measured as follows in the room where the gel-like restoration material was manufactured.
In addition, the concrete defect part (model) was produced as follows.
Kneading with a hand mixer at a ratio of 100 parts by weight of ultra-early strong cement, 200 parts by weight of silica sand No. 3: 5 mixed silica sand at a weight ratio of 1: 1, 60 parts by weight of water and 1 part by weight of water reducing material, The mortar was placed in a 200 x 200 x 10 mm formwork, covered with vinyl (wrap) after placing, and air was inserted into the boundary between the mortar and the vinyl from the top of the vinyl at approximately 10 locations with a diameter of about 10 mm. A simulated defect part having a depth of 3 to 5 mm was produced, and the mortar was cured. The mortar was prepared in a room adjusted to a temperature of 20 ° C. and a humidity of 85% RH, and the mortar was demolded after 3 hours and cured for one day.

[Evaluation of fillability]
The gel restoration material sample was filled into the concrete defect using a trowel and spatula. The filling properties were evaluated according to the following criteria, and the results are shown in Table 1.
○: No sagging occurred on the vertical surface and the upper surface, and the defect could be filled without gaps.
Δ: Low viscosity, no sagging on the vertical surface, but sagging on the upper surface; or high viscosity, it was difficult to fill the defect part without gaps.
X: Sagging occurred even on a vertical surface because of too low viscosity; or it was difficult to fill the defect part because of too high viscosity.

[Evaluation of workability]
The workability when filling a gel-like restoration material sample into a concrete defect (model) with a trowel or spatula was evaluated according to the following criteria, and the results are shown in Table 1.
○: Good separation of iron and spatula and good filling workability.
(Triangle | delta): Separation of iron and spatula was not so good, and it could not be said that filling workability was good.
X: Separation of iron and spatula was poor and filling workability was poor.

[Evaluation of curing status]
The curing condition after filling the gel restoration material sample into the concrete defect (model) using a trowel and spatula was evaluated according to the following criteria, and the results are shown in Table 1.
○ Hardened within 12 hours after filling to 1 cm thickness.
Δ: cured to 12 cm after filling to 1 cm thickness.
X: Not cured within 24 hours after filling to 1 cm thickness.

[Measurement of bending strength and compressive strength]
The bending strength and compressive strength were respectively filled with a gel-like restoration material sample in 10 mm × 10 mm × 40 mm and 10 mm × 10 mm × 10 mm molds, and cured by spraying with water. It measured using "Autograph AG-G 50kN" made from a manufacturer.
The results are shown in Table 1.

[Measurement of adhesion strength]
A 40 × 40 × 10 mold is placed on a substrate, a gel-like restoration material sample is filled so as to be applied with a spatula, and cured by spraying water to prepare a test piece. JIS A 1171 “Testing of polymer cement mortar According to “Method 7.3 Adhesive Strength Test”, the adhesion strength was measured using “adhesive peel tester BA-800D” manufactured by Maruhishi Kagaku Seisakusho at a material age of 7 days.
In all of Examples 1 to 6, the adhesion strength was 1.0 N / mm ² or more.

From the results of Table 1, the restoration materials of Examples 1 to 6 having a viscosity at 20 ° C. of more than 500 Pa · s and not more than 3000 Pa · s are good in filling property, workability, and curing state, It can be seen that the bending strength and compressive strength are sufficient. And the restoration | repair material of Examples 1-6 hardly observed material separation at the time of storage in 5-30 degreeC, and the favorable workability | operativity at the time of storage is also ensured.
Furthermore, it is known that these restoration materials of the present invention can be used almost throughout the year in view of viscosity change at 5 to 30 ° C. and data on material separation.

Claims (3)

  It contains a cement, a fine aggregate, all or part of which is a lightweight fine aggregate, a water-soluble organic solvent having a boiling point of 30 to 100 ° C., and a thickener, and has a viscosity at 20 ° C. of 500 Pa · A repair material for a cross-sectional defect of a concrete structure, characterized by being over s and below 3000 Pa · s.   The unit cement amount is 500 to 1200 g / l, the fine aggregate is 50 to 300 parts by volume with respect to 100 parts by volume of the cement, and the water-soluble organic solvent having a boiling point of 30 to 100 ° C. is 25 to 25% with respect to the total amount of cement and fine aggregates. The restoration material for a cross-sectional defect of a concrete structure according to claim 1, comprising 55% by mass and a thickening material.   A method for repairing a cross-sectional defect in a concrete structure, wherein the repaired portion to be cleaned is filled with the restoration material according to claim 1 and sprayed with water.