JP5234757B2 - Adhesion method of surface protective material and repair method using the same - Google Patents

Description

  The present invention mainly relates to a method for bonding a surface protection material in the field of civil engineering and construction, and a repair method using the same.

In the civil engineering and construction fields, when repairing a deteriorated structure, various materials are applied to the concrete surface for the purpose of removing the deteriorated part and repairing it with a new repair material with excellent durability and shielding the deterioration factors. Lined up works and makeup works to take into account the aesthetics of the surface.
In these constructions, there is a case where roughening is carried out in order to ensure adhesion with the material for bonding the surface of the underlying concrete or mortar. The roughening is generally performed by sandblasting, water jet or the like. In both cases, the construction cost is high because it is performed by a specialized contractor using a dedicated system. When constructing a small area, the cost is further increased. Therefore, manual work such as an electric pick or Thunder Keren is often performed. However, there is a high possibility of inducing cracks in the underlying concrete, and there are cases where sufficient adhesion with the surface protective material cannot be secured.
On the other hand, in the new construction, there is a method in which hardening near the concrete surface is delayed and washed with a high washer or the like, and the aggregate is raised on the surface. In this method, oxycarboxylic acids such as citric acid and gluconic acid are used as agents that delay the hardening of cement. (See Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 10-45992 JP-A-10-202616

  The present invention provides a method for adhering a surface protective material that can easily adhere a surface protective material without using a dedicated system by using a specific organic acid for roughening the surface of concrete or mortar as a base. .

  That is, (1) Surface protection characterized in that glycolic acid is applied to the mortar or concrete surface to which the surface protective material is bonded, and the surface protective material is bonded after decomposing the cement hydrate on the surface portion. (2) Adhering a surface protective material after applying a primer after decomposing cement hydrate, (3) Adhering method of surface protective material, (3) Surface protective material is cement (1) or (2) the method for adhering a surface protective material, which is any one of paste, mortar, concrete, resins, emulsion-based film, or impregnated material, (4) (1) to ( 3) A method for repairing a concrete structure using the method for adhering a surface protective material according to any one of 3).

  According to the method for adhering a surface protective material of the present invention, the surface protective material can be easily adhered without using a dedicated system.

Hereinafter, the present invention will be described in detail.
In the present invention, “%” is based on mass unless otherwise specified.

  Glycolic acid used in the present invention is a kind of oxycarboxylic acid, and its aqueous solution is acidic. In general, because of its low corrosivity, there are uses for household and industrial cleaning agents (scale removal), boiler cleaners, pH adjusters, cosmetic raw materials, biodegradable polymer raw materials, and the like. In recent years, consideration for the environment has become important, and since it is odorless, non-toxic and biodegradable, it can be used as a substitute for various acids. In the field of cement-based materials, oxycarboxylic acid is used as a set retarder for cement, and citric acid, tartaric acid, gluconic acid, and salts thereof are mainly used. Glycolic acid is characterized by a higher ability to dissolve cement hydrate than these acids. Therefore, when roughening the surface of concrete or mortar, it becomes possible to process quickly.

The method of applying glycolic acid to the surface of mortar or concrete is not particularly limited, but there are, for example, a method of applying to the surface of concrete or mortar with a brush or roller, and a method of spraying using a sprayer. There is also a method of adhering to the surface of concrete or mortar by soaking in a sponge or cloth.
Glycolic acid is available in powder and aqueous solution. In the case of powder, it may be used by dissolving in water. The concentration which dissolves in water is not particularly limited as long as it is a concentration range in which the surface of concrete or mortar can be sufficiently roughened.
The time required for roughening can be adjusted from several minutes to several days depending on the acidity. What is necessary is just to use 40 to 80% of aqueous solution when succeeding a surface protection material immediately, and what is necessary is just to use 5 to 20% of use liquid if it is after the next day.
After applying glycolic acid, it may be left as it is applied, or roughened while rubbing with a brush or the like.
The amount of glycolic acid applied is 50 to 200 g / m ² as a guide at a time, and when it is determined that the coarsening is insufficient, it may be applied in several steps.
When it is judged that the roughening has been completed sufficiently, the surface may be washed with water and glycolic acid may be washed away.

The primer used in the present invention exhibits an effect of further enhancing the adhesive force when bonding the surface protective material. A primer is applied after the roughening treatment with glycolic acid is completed.
The type of primer is not particularly limited, and generally commercially available ones can be used. For example, an ethylene-vinyl acetate-based or acrylic ester-based aqueous polymer dispersion, an epoxy resin-based primer, or a paste in which an inorganic powder such as cement is mixed can be used. The amount of primer used is not particularly limited, and is based on the manufacturer's specifications.
The method for applying the primer is not particularly limited, and any of brush coating, roller coating, and spraying is possible.

The surface protective material of the present invention is cement paste, mortar, concrete, resins, emulsion-based film, and impregnated material, and can be applied as long as it is commercially available.
Cement paste is manufactured with various Portland cements specified in JIS R 5210, various mixed cements specified in JIS R 5211, JIS R 5212, and mixed admixtures more than specified in JIS. Blast furnace cement, fly ash cement, silica cement, filler cement mixed with limestone powder, cement using one or more selected from alumina cement, water, for example, polymer admixture or rust prevention The thing which mix | blended the agent etc. are mentioned.
The mortar is mainly composed of the above-mentioned cement mixed with water and sand (fine aggregate), and examples thereof include various repair materials and various grout materials.
Concrete mainly consists of the above-mentioned cement mixed with water, sand (fine aggregate) and gravel (coarse aggregate). These include high-strength admixtures, rapid setting agents, expansive materials, Special concrete containing hardwood and dispersant is also included.
Examples of resins include epoxy resins, acrylic resins, vinyl ester resins, urethane resins, polyester resins, chloroprene rubber, butadiene rubber, and silicone resins used as surface coating materials and adhesives for preventing peeling. And fluorine-based resin. In addition, as a flaking prevention measure, you may combine with fiber sheets, such as a vinylon fiber sheet, a carbon fiber sheet, and an aramid fiber sheet.
Emulsion coatings include styrene-butadiene latex, chloroprene latex, acrylonitrile-butadiene latex, methacrylic acid-butadiene latex, butadiene latex, copolymer emulsions containing polyvinyl acrylate, and polyvinyl acetate emulsion. , Ethylene-vinyl acetate emulsion, vinylidene chloride-vinyl chloride emulsion, epoxy resin emulsion, vinyl acetate-vinyl versatate emulsion, and a mixture of two or more selected from these polymer emulsions.
Examples of impregnated materials include silane-based materials and silicate-based materials.
These surface protective materials can be used in various combinations.

  The method for repairing a concrete structure using the method for adhering a surface protective material of the present invention is not particularly limited. For example, construction for covering the surface of a concrete structure with a resin or polymer cement mortar, or a building For example, a work to attach tiles to the outer wall of the building.

"Reference Example 1"
A 10% aqueous solution of the acid shown in Table 1 was prepared, and the amount of dissolved cement paste per hour was determined. The results are shown in Table 1. The hardened cement paste was prepared and cured for 3 months at a temperature of 20 ° C. and a humidity of 60%.

<Materials used>
Formulation of hardened cement paste: Cement: Water = 1: 0.3 (mass ratio)
Cement: Ordinary Portland cement, commercial water: tap water A: glycolic acid, commercial acid B: citric acid, commercial acid C: gluconic acid, commercial acid D: hydrochloric acid, commercial acid E: sulfuric acid, commercial product

<Test method>
100 g of a cement paste cured body was immersed in 1 liter of a 10% aqueous solution of each acid (temperature 20 ° C., without stirring), and the amount dissolved after 30 minutes was determined. Moreover, the external appearance (after drying) of the cured body surface after a dissolution test was also confirmed visually.

  From Table 1, it can be seen that the amount of cement hydrate dissolved differs depending on the type of acid. It can be seen that hydrochloric acid and sulfuric acid make the surface of the cured body brittle, although the dissolved amount is large.

"Reference Example 2"
It carried out similarly to the reference example 1 by changing the density | concentration of acid A (glycolic acid) solution. The results are shown in Table 2.

  From Table 2, it can be seen that the amount of cement hydrate dissolved varies depending on the concentration of glycolic acid used in the present invention. It can be seen that even if the acid concentration is changed and the amount of dissolution increases, the surface of the cured body does not become brittle.

"Example 1"
The glycolic acid aqueous solution of Experiment No.2-3 was applied to the surface of concrete (3 months old) with a design standard strength of 24 N / mm ² with a roller. The coating was carried out in two portions at an amount of 100 g / m ² . Application interval is 30 minutes. After completion of roughening (after 1 hour), wash with water to wipe off excess water, and measure adhesion strength by adhering a surface protective material with and without applying primer (coating amount is 100 g / m ² ) did. The results are shown in Table 3.
For comparison, citric acid, gluconic acid, sulfuric acid, and aqueous hydrochloric acid solution having the same concentration were similarly tested using the surface protective material c after treatment.

<Test method>
Adhesion strength: A cut was made with a concrete cutter to be 4 cm long × 4 cm wide, and the adhesion strength was measured with a Kenken-type adhesion tester at a material age of 28 days.

<Materials used>
Surface protective material a: rust inhibitor mixed polymer cement paste, ordinary Portland cement (manufactured by Denki Kagaku Kogyo) 100 parts, lithium nitrite aqueous solution (made by Denki Kagaku Kogyo Co., Ltd., trade name “RIS111”) ”) And a polymer cement paste in which 10 parts of an ethylene-vinyl acetate emulsion (trade name“ RIS211E ”, manufactured by Denki Kagaku Kogyo Co., Ltd.) having a solid content of 45% is added and mixed, coating thickness: 2 mm
Surface protective material b: Concrete (W / C = 55% of the design strength is ^{24N / mm 2, s / a} = 47.2%, cement 299kg / ^{m 3,} water 164 kg / ^{m 3,} fine aggregates 857kg / m ^3, coarse aggregate 977kg ^/ m 3, AE water reducing agent 3.0 kg ^{/ m} 3), coating thickness: 50mm
The following were used for cement, fine aggregate, coarse aggregate, and AE water reducing agent.
Cement: Ordinary Portland cement, manufactured by Denki Kagaku Kogyo, density 3.15 g / cm ³
Fine aggregate: Sand from Himekawa water system, Niigata prefecture, density 2.62g / cm ³ , 5mm below Coarse aggregate: Crushed stone from Himekawa water system, Niigata prefecture, density 2.66g / cm ³ , Gmax 25mm
AE water reducing agent: manufactured by BASF Pozoris Bussan Co., Ltd., trade name “Pozoris No. 70”
Surface protection material c: polymer cement mortar for plasterer, manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “RIS322 Ace”, coating thickness: 20 mm
Surface protective material d: acrylic resin, coating thickness: 1 mm, commercially available, manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Hard Rock II, DK550-003”
Surface protective material e: acrylic-styrene emulsion, coating thickness: 0.1 mm, commercial product, manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Krakoff”
Surface protective material f: Silane-based impregnated material, coating thickness: 0.1 mm, commercially available product, manufactured by Hengwa Chemical Co., Ltd., trade name “COMFIX SM-9”
Primer: Ethylene-vinyl acetate emulsion, solid content 15%, commercially available product, manufactured by Denki Kagaku Kogyo Co., Ltd., 3-fold dilution of trade name “RIS211E”

  From Table 3, it can be seen that by using the glycolic acid of the present invention, it is possible to roughen the surface without altering the surface, and it is possible to ensure adhesion with each surface protective material. It can be seen that the adhesion can be further improved by using the primer together. On the other hand, when it processes with acids other than glycolic acid, it turns out that securing of adhesive force is difficult.

  Since the surface protective material can be easily bonded without using a dedicated system by the surface protective material bonding method of the present invention, it can be widely used for repair work for constructing various surface protective materials.

Claims (3)

After applying glycolic acid 50-200 g / m ² on the surface of the mortar or concrete to which the surface protective material is bonded and decomposing the cement hydrate on the surface part, it is a polymer cement mortar for plasterers or an acrylic resin. A method for adhering a surface protective material, comprising adhering a surface protective material. The method for bonding a surface protective material according to claim 1, wherein the surface protective material is bonded after applying the primer after decomposing the cement hydrate. A method of repairing a concrete structure using the bonding method according to claim 1 or 2, wherein the surface protecting material according.