JP2000204770A - Method for protecting concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for protecting concrete structure by which the reinforcing performance by a fiber reinforced resin layer provided on the surface of a concrete structure can be maintained even when the atmospheric temperature rises by suppressing the temperature rise of the resin layer. SOLUTION: A method for protecting concrete structure is characterized in that at least one heat insulating layer having a coefficient of thermal conductivity of <=500 kcal/m2.h. deg.C is formed on the surface of a fiberglass-reinforced resin layer provided on the surface of a concrete structure to reinforce the structure and, if necessary, a finish coating film is further formed on the surface of the heat insulating film. It is preferable to adjust the solar absorptivity of the outermost surface of the heat insulating layer or the surface of the finish coating film to <=0.5 and to form the heat insulating layer of an acrylic rubber coating layer and/or a fiber layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing the softening and deterioration of a fiber reinforced resin layer in a concrete structure reinforced with a fiber reinforced resin layer. The concrete structure protection method of the present invention can be used in fields such as civil engineering and construction.

[0002]

2. Description of the Related Art In recent years, as a method of reinforcing concrete structures, in particular, seismic reinforcement of concrete structures such as bridge piers, bridges, floor slabs, and buildings, a method of providing a fiber reinforced resin layer on the surface of a concrete structure. Has been done. This method has advantages in that the construction period is shorter, the outer shape of the structure does not change so much, and the construction is small-scale, as compared with a method of rolling up a steel sheet on the surface of the structure or a method of additionally striking concrete. The fiber-reinforced resin layer used in the above-mentioned reinforcing method generally includes a fiber sheet formed of carbon fiber, aromatic polyamide fiber (aramid fiber), glass fiber, etc., a fiber reinforcing material such as cloth and nonwoven fabric, and a fiber reinforced material. It is made of a thermosetting resin such as an epoxy resin or an unsaturated polyester resin which has been impregnated and cured. As the thermosetting resin, there are a room temperature curing type resin and a heat curing type resin. Since the resin can be cured by being left as it is after impregnation into the fiber, there is an advantage that a heat-curing operation at a construction site is unnecessary, and therefore, a room-temperature-curable resin is preferably used.

However, since thermosetting resins generally have a low softening temperature, a fiber-reinforced resin layer using a thermosetting resin is
When the fiber reinforced resin layer becomes high temperature due to rising temperature and direct sunlight, it may soften and fail to exhibit sufficient reinforcement performance. , This problem is more pronounced.

[0004] In order to obtain good reinforcement performance even at high temperatures, Japanese Patent Application Laid-Open No. 7-189426 discloses that the resin constituting the fiber reinforced resin layer has a glass transition temperature after heat curing of 70 ° C. or more. It is disclosed that a resin having a curing reaction rate of 80% or more after curing at 20 ° C. for 7 days is used. However, even with this method, the effect of preventing the softening of the fiber reinforced resin layer may be insufficient, and the resin usable for the fiber reinforced resin layer is limited.

[0005]

As a means for maintaining the reinforcing performance of the fiber-reinforced resin layer, the inventors of the present invention have proposed a method of forming a coating layer formed on the surface of the fiber-reinforced resin layer, which has not been noticed so far. Focusing on `` insulation properties '', we conducted intensive studies based on the presumption that if the temperature increase of the fiber reinforced resin layer is suppressed by this coating layer, the reinforcing performance of the concrete structure will be maintained even when the temperature rises etc. I went. That is, an object of the present invention is to suppress a rise in the temperature of the fiber-reinforced resin layer by a coating layer provided on the surface of a concrete structure reinforced by the fiber-reinforced resin layer. An object of the present invention is to provide a method for protecting a concrete structure that maintains the reinforcing performance of a resin layer.

[0006]

Means for Solving the Problems When the concrete surface is covered with a heat insulating layer having a heat conduction coefficient of not more than a predetermined value, the present inventors have found that the heat insulating effect of the heat insulating layer makes the softening of the fiber reinforced resin layer less effective. Thus, the present invention has been completed.

That is, in the method for protecting a concrete structure according to the first aspect of the present invention, the surface of the fiber reinforced resin layer of the concrete structure reinforced by the fiber reinforced resin layer provided on the surface is provided with a heat transfer coefficient of 500 Kcal. / M ²
A feature is that at least one heat-insulating layer of h · ° C. or lower is formed, and an overcoat material coating layer is further formed on the heat-insulating layer as required. By providing the heat-insulating layer, heat from outside air is less likely to be transmitted to the fiber-reinforced resin layer, so that a rise in temperature of the fiber-reinforced resin layer can be suppressed, and softening of the resin layer can be prevented.

[0008] The method for protecting a concrete structure according to the second invention is the method for protecting a concrete structure according to the first invention, wherein the solar radiation absorptivity of the outermost surface of the heat insulating layer or the surface of the top coat layer is 0.5.
It is characterized by the following. By lowering the solar absorptivity in this manner, heat is less likely to be received by the solar radiation, so that the temperature rise on the surface of the heat insulating layer is reduced, and the temperature rise of the fiber reinforced resin layer is reduced.

[0009] In a third aspect of the present invention, in the method for protecting a concrete structure, the heat insulating layer is an acrylic rubber coating layer in the first or second aspect. This acrylic rubber-based coating film layer has the characteristics that it has a relatively low thermal conductivity, is easy to form a coating film, has waterproofness and moisture permeability, and is excellent in crack followability. Therefore, when an acrylic rubber-based coating layer is used for the heat insulating layer, the heat insulating layer prevents the temperature of the fiber reinforced resin layer from rising and maintains the strength, and at the same time, prevents moisture from coming from outside the concrete structure. In addition, the action of shutting off the internal moisture and expelling the internal moisture can be obtained, so that the fiber reinforced resin layer is prevented from being deteriorated by the moisture. This effect of preventing deterioration is particularly prominent when the resin constituting the fiber reinforced resin layer is an epoxy resin.

[0010] In the method for protecting a concrete structure according to a fourth aspect of the present invention, in the methods of the first to third aspects, the heat insulating layer is a fiber layer. By providing the fiber layer, it becomes easy to reduce the heat conduction coefficient of the entire heat insulating layer.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

In the method for protecting a concrete structure according to the present invention, a heat insulation layer having a heat conduction coefficient of a predetermined value or less is provided on a fiber reinforced resin layer provided on the surface of the concrete structure to reinforce the concrete structure. Provide. Here, as a fiber constituting the fiber reinforced resin layer, for example, carbon fiber, aromatic polyamide fiber (aramid fiber), glass fiber, silicon carbide fiber, boron fiber, ceramic fiber, metal fiber, vinylon fiber, nylon fiber, Fiber reinforcing materials such as fiber sheets, cloths and nonwoven fabrics formed from one or more fibers selected from polyester fibers and the like can be used. Of these, carbon fibers are preferably used.

The resin constituting the fiber reinforced resin layer includes a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, a polyurethane resin, a diallyl phthalate resin, a phenol resin, a polyacetal resin, a saturated polyester resin, and a polyamide. Thermoplastic resins such as resin, polystyrene resin, polycarbonate resin, vinyl chloride resin, polyethylene resin, polypropylene resin, and acrylic resin can be used. In the present invention, a thermosetting resin is preferably used, and an epoxy resin is more preferably used.

Preferably, the fiber reinforced resin layer of the present invention is obtained by curing an epoxy resin at room temperature.
Specifically, for example, an epoxy resin composition containing, as essential components, an epoxy resin such as bisphenol A or bisphenol F and a curing agent composed of a cyclic aliphatic amine, a fatty aromatic amine or an aromatic amine or a modified product thereof. , 5 to 60 ° C (more preferably 10 to 50 ° C).

The method for forming the fiber reinforced resin layer is not particularly limited, and may be a conventionally known method. For example, a method in which a fiber reinforcement is impregnated with a resin at a reinforcement site in advance, and then the fiber reinforcement is attached to the surface of a concrete structure. The resin is painted on the surface of the concrete structure, and the fiber reinforcement is placed on the resin. Pressing and pressing to impregnate the resin into the fiber reinforcement, applying a primer to the surface of the concrete structure and attaching the fiber reinforcement, and then applying and impregnating the resin from above the fiber reinforcement, etc. Can be used.

An example of a method for forming a fiber reinforced resin layer will be described more specifically. First, a primer is applied to a portion where a fiber reinforced resin layer is to be formed for the purpose of improving the adhesiveness. As the undercoat material, a solvent type epoxy resin solvent solution, a solventless type epoxy resin, or an epoxy resin emulsion and other general emulsions or adhesives are used. This undercoating material may be applied by a usual method, for example, a method of applying with a brush or a roller, or a method of spraying with a spray gun or the like to form a coating film of the undercoating material. Next, an epoxy resin for fiber reinforcement is applied to the surface of the undercoat material coating film using a roller or a brush. As the epoxy resin, those having adhesiveness to the undercoat material coating film and the fiber layer, and those which are of a room temperature curing type as described above are preferably used.

Next, the "heat insulating layer" in the method of the present invention will be described. The heat insulating layer formed in the present invention has a characteristic that the heat conduction coefficient is 500 Kcal / m ² · h · ° C. or less. This “heat conduction coefficient (kcal / m ² · h ·
° C) ”is, as shown in the following equation (1), the thermal conductivity λ (kcal / m · h · ° C) specific to the material, and the thickness (m) of the material.
Divided by the thermal conductance. Thermal conductivity coefficient (kcal / m ² · h · ° C.) = [Thermal conductivity (kcal / m · h · ° C.)] / [Film thickness (m)] (1) Temperature difference on both sides of a coating film made of this material When there is, the heat transfer amount of the coating film per unit time is determined by “heat conductivity coefficient × temperature difference”. That is, when one of the coating films has a higher temperature than the other, the smaller the thermal conductivity coefficient of the coating film, the more difficult it is for one heat to be transmitted to the other, and it can be said that the heat insulating property of this coating film is high. Thus, the thermal conductivity coefficient is obtained as “thermal conductivity / film thickness”. Therefore, in order to obtain a heat insulating layer having a low thermal conductivity, the heat insulating layer may be formed from a material having a low heat conductivity, a material that easily forms a thick layer, or a material having both of them.

The heat insulating layer of the present invention has a heat conductivity coefficient of 500K.
cal / m ² · h · ° C or less (more preferably 300 Kc
al / m ² · h · ° C or less, more preferably 200 Kc
al / m ² · h · ° C. or less), so that the heat insulating property is high. Thereby, the temperature of the fiber reinforced resin layer can be prevented from rising and its softening can be sufficiently suppressed. Further, since the heat insulating layer of the present invention has such a low heat conduction coefficient, it can have a high heat insulating property with a simple configuration. Although the lower limit of the heat conduction coefficient of the heat insulating layer is not particularly limited,
Usually, it is 0.1 Kcal / m ² · h · ° C. or more. The heat insulating layer having a heat conduction coefficient of less than 0.1 Kcal / m ² · h · ° C. may be too thick to cause a problem in construction.

In the method of the present invention, only a single heat insulating layer may be formed, or a plurality of heat insulating layers may be formed.
Also, each insulation layer may be formed from one type of material,
It may be formed from two or more materials. In the case of forming a plurality of heat insulating layers, at least one of the heat insulating layers may have a heat conduction coefficient equal to or less than the above value. The thickness of the entire heat insulating layer is usually 0.1 mm to 100 mm, and 0.5 mm to 3 mm.
It is preferably 0 mm.

In the concrete protection method of the present invention, the outermost surface of the heat-insulating layer or the surface of the topcoat material coating layer preferably has a solar absorptivity of 0.7 or less, as in the second invention. More preferably, the ratio is 0.5 or less. Further, the lower limit of the solar absorptivity is not particularly limited, but is 0.2 or more in a usual paint. The “solar absorptance” is determined by the following equation (2).
It is described in ISR3106. If the outside temperature is the same,
The lower the solar absorptivity, the less heat is received by the solar radiation. Therefore, the temperature rise on the heat insulating layer surface is reduced, and the temperature rise of the fiber reinforced resin layer is reduced. 1- (solar transmittance + solar reflectance) (2)

As the heat insulating layer of the present invention, acrylic rubber,
Urethane rubber, styrene-butadiene rubber, ethylene-
Examples include a flexible resin layer formed of a flexible resin such as propylene rubber and natural rubber, and a hard resin layer formed of an epoxy resin, an acrylic resin, a urethane resin, a polyester resin, or the like. As the heat insulating layer of the present invention, a flexible resin layer is preferable because it can follow cracks of a concrete structure, and among the flexible resin layers, an acrylic resin layer formed using an acrylic rubber-based composition made of acrylic rubber is used. Rubber-based coating layers are particularly preferred.
This acrylic rubber-based composition tends to form a small coating layer of heat transfer coefficient it is easy thick film coating, materials for forming the heat transfer coefficient 500Kcal / m ² · h · ℃ less heat insulating layer It is suitable. Acrylic rubber has moisture permeability and high crack followability, and is also excellent in waterproofness, and therefore has a thermal conductivity of 500 Kcal / m ² · h.
Acrylic rubber-based coating film having a temperature higher than ° C. is also useful as a heat insulating layer having excellent waterproofness and moisture permeability. In this case, a heat insulating layer having a thermal conductivity of 500 Kcal / m ² · h · ° C. or less may be separately provided. Hereinafter, the acrylic rubber composition will be described in more detail.

The acrylic rubber-based composition used for forming the acrylic rubber-based coating film layer of the present invention contains 30 alkyl (meth) acrylates having 4 to 10 carbon atoms in the alkyl group.
It is preferable to use an acrylic rubber-based copolymer having a copolymerization ratio of about 98% by weight. When the carbon number of the alkyl group is 4 to
Specific examples of the alkyl (meth) acrylate which is 10 include n-butyl (meth) acrylate, iso-butyl (meth) acrylate, sec-butyl (meth) acrylate, n-amyl (meth) acrylate, and iso-
Amyl (meth) acrylate, n-hexyl (meth) acrylate, n-hexyl (meth) acrylate, n-
Pentyl (meth) acrylate, oxoheptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, oxononyl (meth) acrylate, n-decyl (meth) acrylate And oxodecyl (meth) acrylate. Alkyl (meth) acrylates having an alkyl group having less than 4 carbon atoms are not preferred in terms of alkali resistance, while those having more than 10 carbon atoms have reduced cold resistance. The copolymerization ratio of the above monomers needs to be 30 to 98% by weight, and preferably 50 to 90% by weight. This ratio is 3
If the amount is less than 0% by weight, the ability of the coating film to follow a base crack, water resistance, and alkali resistance are reduced. On the other hand, if it exceeds 98% by weight, a coating film having sufficient strength may not be obtained.

The acrylic rubber-based copolymer includes, in addition to the alkyl (meth) acrylate having an alkyl group having 4 to 10 carbon atoms, another monomer having an unsaturated ethylene bond copolymerizable therewith. Is copolymerized. The “other monomer” includes (meth) acrylic acid, styrene, acrylonitrile, vinyl acetate, vinyl chloride, butadiene, (meth) acrylic acid, glycidyl (meth) acrylate, N-methylol (meth) acrylamide, and carbon Alkyl (meth) acrylates of formulas 1 to 3 and the like can be mentioned.

The acrylic rubber-based composition is excellent in safety, is excellent in workability because it is a one-pack type, has no stickiness, and is resistant to water, chemicals, ultraviolet light and ultraviolet light. From the viewpoint of good ozone properties, it is preferable to use an aqueous emulsion of an acrylic rubber-based copolymer. The ratio of the acrylic rubber-based copolymer in the emulsion was 30 to 7
It is preferably 0% by weight. This acrylic rubber-based copolymer emulsion is obtained by, for example, emulsion-polymerizing the monomer in the presence of a surfactant. As the surfactant, any of anionic, nonionic and cationic surfactants can be used. The amount of the surfactant is 0.1 to 1 based on 100 parts by weight of the acrylic rubber-based copolymer.
It is preferably 0% by weight. If the amount of the surfactant is less than 0.1% by weight, the emulsion lacks stability. On the other hand, when the amount exceeds 10% by weight, the drying property and the water resistance of the coating film are reduced.

The acrylic rubber-based composition is used for the purpose of strengthening the acrylic rubber-based coating layer obtained from this composition, reducing the tackiness of the coating layer surface, and improving workability. A filler may be blended. The amount of the filler is 30 parts per 100 parts by weight of the acrylic rubber-based copolymer.
The amount is preferably from 300 to 300 parts by weight, more preferably from 50 to 150 parts by weight. Filler content is 30
If the amount exceeds 0 parts by weight, the adhesiveness, elongation and waterproof function of the coating layer may be impaired. Specific examples of the filler include silica sand, talc, calcium carbonate, kaolin, gypsum, diatomaceous earth, titanium oxide, and one or more cements such as various portland cements, blast furnace cements, and alumina cements. When cements are compounded as a filler, the compounding amount is preferably 10 to 200 parts by weight based on 100 parts by weight of the acrylic rubber-based copolymer. If the amount is less than 10 parts by weight, the strength of the coating layer is undesirably reduced. On the other hand, when the blending amount is 2
If the amount is more than 00 parts by weight, the flexibility of the coating film layer may be reduced, cracking may be insufficient, and waterproofness may be impaired. Further, the acrylic rubber-based composition,
If necessary, a viscosity stabilizer, an antifoaming agent and the like can be blended in a range of 5 parts by weight or less based on 100 parts by weight of the acrylic rubber-based copolymer.

The acrylic rubber coating layer formed from this acrylic rubber composition has an elongation at 50 ° C. of 50%.
It is preferable that the water vapor permeability is 5 g / m ² · day or more. 50% elongation at 20 ° C
Otherwise, the ability to follow concrete cracks will be insufficient, and as a result, waterproofness may not be obtained. On the other hand, if the elongation exceeds 200%, the film becomes weak against abrasion and impact, and the durability of the coating film layer becomes insufficient.
Further, if the water vapor permeability is less than 5 g / m ² · day, it is difficult to release the water inside the concrete, so that the inside of the concrete cannot be dried, thereby inducing an alkali-aggregate reaction, Moisture from inside the concrete may cause the coating layer to bulge or the resin forming the fiber reinforced resin layer to deteriorate.

The above-mentioned acrylic rubber-based coating layer can be used alone as the heat insulating layer of the present invention when the coating layer achieves a thermal conductivity of not more than the above-mentioned predetermined value. At this time, the thickness of the acrylic rubber-based coating film was 0.2
５5 mm, more preferably 0.5-2 mm. When the thickness is less than 0.2 mm, it is difficult to make the thermal conductivity coefficient of this coating layer 500 Kcal / m ² · h · ° C. or less, and the ability to follow cracks in concrete is insufficient, and water resistance is obtained. May disappear. On the other hand, when the thickness exceeds 5 mm, the inside of the concrete cannot be dried because the water vapor permeability becomes small, and the alkali aggregate reaction is induced, the coating layer is swollen, and the fiber reinforced resin layer is removed. The resin to be formed may be deteriorated.

The acrylic rubber-based coating layer can be formed from the acrylic rubber-based composition by a conventional method such as coating with a trowel, brush or roller, or spraying with a machine such as a ricin gun or a spray gun. I just need.
The viscosity at the time of coating varies depending on the application method.
0 cps or more (B-type viscometer, 12 rotations, rotor No.
(4, 20 ° C) is preferable because of excellent workability, and more preferably 1,000 to 50,000 cps. If the viscosity is less than 300 cps, it becomes difficult to apply a thick coating at a time. When the viscosity exceeds 50,000 cps, there is an advantage that thick coating can be performed, but there is a case where a difficulty occurs in construction.

The heat insulating layer of the present invention may be a woven or non-woven fiber layer made of polyester fiber, polypropylene fiber, glass fiber, carbon fiber, vinylon fiber, aramid fiber, polyamide fiber, acrylic fiber or the like.
This fiber layer can be used in combination with another heat insulating layer. In this case, the fiber layer may be arranged on the back surface side of the other heat insulating layers, and when two or more other heat insulating layers are formed, they may be arranged between these heat insulating layers. Further, two or more fiber layers may be provided, for example, inside the other heat insulating layer and on the back side thereof. Since this fiber layer generally has high heat insulating properties because of the inclusion of air in the fibers, it is suitable as a constituent layer having a heat conduction coefficient of 500 Kcal / m ² · h · ° C. or less. Has the effect of reducing the coefficient of thermal conductivity of Further, effects such as improving the strength of the heat insulating layer and preventing concrete from falling off can be obtained. The fiber layer of the present invention is preferably combined with an acrylic rubber-based coating layer, and in this case, a nonwoven fabric made of polyester fiber is used from the viewpoint of excellent adhesion to the coating layer and excellent retention of the fiber layer against external force. Is preferred. In order to improve the adhesive strength of the heat insulating layer, a discontinuous nonwoven fabric can be used.

As a method for disposing the fiber layer on the back side of the coating layer, for example, there is the following method. First, a primer is applied to a portion where the heat insulating layer is to be formed, for the purpose of improving the adhesiveness. As the undercoat material, a solvent type epoxy resin solvent solution, or an epoxy resin emulsion and other general emulsions or pressure-sensitive adhesives are used.
This undercoat material can be applied by a usual method, for example, by a general method such as applying with a brush or a roller, or spraying with a spray gun or the like to form an undercoat material coating film. Next, an adhesive is applied with a roller, a brush, or the like. As the adhesive, various adhesives can be used as long as they have adhesion to the undercoat material coating film and the fiber layer, and NBR-based synthetic rubber adhesives, epoxy-based adhesives, polyester-based adhesives, and polyurethane-based adhesives can be used. An adhesive and the like are exemplified. Before the applied adhesive is dried, a material for forming a fiber layer, for example, a polyester nonwoven fabric is attached. Then, on the surface of the fiber layer, a material for forming the coating layer is applied with a trowel, a roller, a brush, or the like and dried to form a coating film in which the fiber layer is disposed on the back side.

In the present invention, it is possible to form only the acrylic rubber-based coating layer as a heat insulating layer as described above. However, in general, adjustment of solar absorptivity, prevention of contamination, and improvement of weather resistance of the heat insulating layer are generally performed. It is preferable to provide an overcoat material coating layer on the surface of the heat insulating layer for the purpose of improving the appearance and the like. Various coating materials can be used as the coating material for forming this coating film layer, such as (meth) acrylic resin paint, (meth) acrylic urethane paint, (meth) acrylic silicone paint,
Fluororesin paints and epoxy resin paints are exemplified.

The coating film layer of the topcoat material has a solar absorptivity of 0.1.
7 or less (more preferably 0.5 or less), the elongation at 20 ° C. is 50 to 500%, and the thickness of the coating film is 5 or less.
Those having a thickness of 0 to 300 μm are preferred. If the elongation at 20 ° C. of the overcoating material coating layer is less than 50%, when this overcoating material coating layer is formed on the flexible resin layer, the ability of the heat insulation layer to follow cracks is reduced, In some cases, the coating layer of the topcoat material itself breaks without being able to follow the flexibility. On the other hand, if the elongation percentage exceeds 500%, it becomes susceptible to contamination from the outside, which is not preferable from an aesthetic standpoint. On the other hand, if the thickness of the overcoat material coating layer is less than 50 μm, the concealing property becomes poor and the appearance is not preferable. On the other hand, if the thickness exceeds 300 μm, it is difficult to release the moisture inside the concrete, so that the inside of the concrete cannot be dried, which induces an alkali-aggregate reaction, the coating layer easily swells, and the fiber reinforced resin. The resin forming the layer may be degraded. In the case where the thickness of the top coat layer is 50 to 300 μm, the heat insulating effect of this top coat layer is usually small. Therefore, in the present invention, the top coat layer is used in combination with the heat insulating layer. Is preferred.

As a preferred embodiment of the method of the present invention, a method of forming the following layers in order from the inside (also referred to as the concrete structure side or the back side) to the outside (also referred to as the outside air side or the front side). No. Note that ~
The heat conduction coefficient of at least one of the constituent layers in the heat insulating layer is 500 Kcal / m ² · h · ° C. or less. Flexible resin layer / coating material coating layer Fiber layer / flexible resin layer / coating material coating layer Flexible resin layer / fiber layer / flexible resin layer / coating material coating layer Flexible with fiber layer disposed inside Flexible resin layer / Flexible resin layer / Finish coating film layer Fiber layer / Flexible resin layer / Flexible resin layer with fiber layer disposed inside / Flexible resin layer / Finish coating film layer

Further, in the present invention, the heat conduction coefficient is 5
A foam layer made of a resin foam such as polyethylene foam or urethane foam can be formed as a heat insulating layer having a temperature of 00 Kcal / m ² · h · ° C. or less. In this case, it is preferable to provide a flexible resin layer and / or an overcoating material coating layer outside the foam layer. A flexible resin layer is provided outside the foam layer, and further overcoating is applied outside the flexible resin layer. It is more preferable to adopt a structure provided with a material coating layer. The heat-insulating layer having such a structure has a large effect of preventing a temperature rise of the fiber-reinforced resin layer by having a low thermal conductivity based on the foam layer and the like and a low solar absorptance adjusted by the overcoat material coating layer. . Further, when the flexible resin layer is an acrylic rubber-based coating layer, the inside of concrete can be kept in a dry state by water vapor permeability and waterproofness based on this acrylic rubber-based coating layer, so that the alkali bone It is excellent in the effect of preventing material reaction and the effect of preventing deterioration of the resin forming the fiber reinforced resin layer.

Regarding the effect obtained by the method of the present invention,
This will be described with reference to the drawings. FIG. 1 is a characteristic diagram showing the relationship between temperature and tensile strength of an epoxy resin obtained by curing bisphenol A at room temperature with various ethylenediamine-based curing agents. As you can see from this figure, 100 ~
In the temperature range up to 150 ° C., the tensile strength of these epoxy resins decreases by about 20% with a temperature rise of 20 ° C. Therefore, when the resin constituting the fiber-reinforced resin layer is a resin exhibiting such characteristics, even if the resin is designed to provide a sufficient reinforcing effect at room temperature, the fiber is reinforced by an increase in outside temperature, direct sunlight, etc. When the temperature of the resin layer rises, a desired reinforcing effect may not be obtained. According to the concrete structure protection method of the present invention,
Since the heat insulating layer having a low thermal conductivity is formed outside the fiber reinforced resin layer, it is possible to suppress a temperature rise of the fiber reinforced resin layer and prevent the fiber reinforced resin layer from softening. The effect of the method for protecting a concrete structure of the present invention is best exhibited when the softening temperature of the resin forming the fiber-reinforced resin layer is 30 to 100 ° C (more preferably 40 to 80 ° C). You.

[0036]

The present invention will be described more specifically with reference to the following examples.

(1) Materials used Acrylic rubber-based composition The following monomers were emulsion-polymerized using sodium dodecylbenzenesulfonate as a surfactant to obtain an acrylic rubber-based copolymer having a solid concentration of 60%. I got an emulsion. [Monomer composition] 2-Ethylhexyl acrylate 92 parts by weight Acrylonitrile 5 parts by weight Methacrylic acid 3 parts by weight The following components were added to 100 parts by weight (as is) of this acrylic rubber-based copolymer emulsion while stirring. An acrylic rubber composition was obtained. [Blend] Calcium carbonate 50 parts by weight Alumina cement 5 parts by weight Sodium polyacrylate 0.1 part by weight The thermal conductivity of the coating film formed from this acrylic rubber composition is 0.16 kcal / m · h · ° C.

Fiber Layer A polyester fiber nonwoven fabric manufactured by Toagosei Co., Ltd., trade name "Aron Buffer Sheet" was used. The thickness of this sheet was 1200 μm and the thermal conductivity was 0.04 kcal / m ·
h · ° C. Epoxy paint An epoxy paint manufactured by Toupe Co., Ltd., trade name “Guard Cleat # 100 middle coat” was used. The thermal conductivity of the coating film formed from this epoxy paint was 0.35 kcal / m
H · ° C. Topcoat paint White and gray paints were used among acrylic urethane-based paints manufactured by Toagosei Co., Ltd., trade name “Aromblecoat T-310”. The thermal conductivity of the coating film formed from this top coating is 0.3 kcal / m · h · ° C.

(2) Application Method (Example 1) The above-mentioned acrylic rubber composition was coated on a surface of a test substrate with a trowel and a roller and dried three times, and an acrylic rubber having a thickness of 1,000 μm was repeated. A system coating layer was formed. The surface of this acrylic rubber-based coating layer is roller-coated with the above-mentioned top coating (white) to a thickness of 1
An overcoat material coating layer (solar absorption rate 0.3) having a thickness of 60 μm was formed, and a heat insulation layer having a configuration of “acrylic rubber-based coating film layer / overcoat material coating” was completed in this order from inside to outside.
This layer, as the heat conduction coefficient 500kcal / m ² · h · ℃ less heat insulating layer, heat conduction coefficient 160kcal / m ² ·
It has an acrylic rubber-based coating layer of h · ° C.

Example 2 The above-mentioned Aron buffer sheet was placed on the surface of a test substrate to form a fiber layer having a thickness of 1200 μm. Next, the above-mentioned acrylic rubber-based composition was coated and dried with a trowel and a roller three times to form an acrylic rubber-based coating layer having a thickness of 1,000 μm. On the surface of this acrylic rubber-based coating film layer, the above-mentioned top coating material (white) is roller-coated to form a 160 μm-thick top coating material coating layer (solar absorption rate: 0.3), and sequentially from inside to outside. A heat-insulating layer having a configuration of "fiber layer / acrylic rubber-based coating layer / coating material coating layer" was completed. This layer is a heat insulating layer having a heat conduction coefficient of 500 kcal / m ² · h · ° C. or less, and has a heat conduction coefficient of 33.3 kcal / m ² · h.
· Fiber layer of ° C. and heat conduction coefficient of 160 kcal / m ² · h
・ It has an acrylic rubber-based coating layer at a temperature of ° C.

(Comparative Example 1) This Comparative Example 1 corresponds to a conventional construction method that does not consider heat insulation. That is, the above-mentioned top coat (white) is coated with a roller and the thickness is 160 μm.
Only the overcoat material coating layer (solar absorption rate 0.3) was formed.

Comparative Example 2 The epoxy paint was applied to the surface of a test substrate to form an epoxy resin layer having a thickness of 200 μm. On the surface of this epoxy resin layer, the above-mentioned top coating material (white) is roller-coated to form a top coating material coating layer (solar absorption rate: 0.3) having a thickness of 160 μm. A heat insulating layer having a configuration of “layer / coating material coating layer” was completed. The thermal conductivity coefficient of this epoxy resin layer is 1750 kcal / m ² · h · ° C., and the heat insulation coefficient of Comparative Example 2 is 500 kcal / m ² ···
It does not have a constituent layer of h · ° C. or less.

(Comparative Example 3) Insulation was performed in the same manner as in Comparative Example 2, except that a gray top coat was used instead of the white top coat to form a top coat layer (solar absorption rate: 0.9). Completed layers.

(3) Evaluation Effect of Maintaining Reinforcement Performance at High Temperature A mortar of 4 × 4 × 16 was prepared by using a mortar composed of a mixture of cement 1, water 0.6 and sand 3 by mass ratio. Primer (Mitsubishi Chemical Corporation, trade name "Eposam Primer XPS301") on the entire surface of the prepared mortar
0.3 kg / m ² was applied with a brush. The next day, 0.3 kg / m ² of an epoxy resin (trade name “Epotherm Resin XL-700S” manufactured by Mitsubishi Chemical Corporation) was primed with a brush, and immediately thereafter, a carbon fiber sheet (manufactured by Mitsubishi Chemical Corporation,
A product name "Riperak 17") was attached without loosening or wrinkling, and air was released while pressing with a rubber spatula. After confirming the impregnation of the carbon fiber sheet surface with the undercoat epoxy resin, the same epoxy resin 0.3 kg /
m ² was overcoated with a brush and finished with a rubber spatula. This was cured for 28 days at a temperature of 20 ° C. and a humidity of 65% to obtain a test substrate.

A test piece was prepared by forming a heat insulating layer on the surface of the test substrate by the working method of the above Examples and Comparative Examples. Each specimen was allowed to stand in the Nagoya industrial coastal zone under the scorching sun of the ground surface temperature of 40 ° C or higher for 4 hours.
The flexural strength of this test piece was measured according to IS R5201 “Physical test method for cement”. The bending strength of the test piece on which the heat insulating layer of Example 1 was formed was left at room temperature (about 20 ° C.) to be 194 kgf / cm ² .

In order to protect the fiber-reinforced resin layer (for example, to block moisture from the outside to prevent deterioration of the epoxy resin constituting the fiber-reinforced resin layer), it is necessary to protect the concrete structure by temperature. In order to follow the expansion and contraction and the shape of the corner portion of this structure, it is desirable that the heat insulating layer has high crack followability. This crack followability was evaluated by the following test.

As shown in FIG. 2, 150 × 75 × 5 mm
A slate plate 2 was cut into one surface and a primer (a solution of an epoxy resin solution manufactured by Toagosei Co., Ltd., trade name "Aromble Coat P-200") was applied to the other surface, which was then used as a test substrate. Used as The heat-insulating layer 1 was formed on the surface coated with the undercoating material by the methods of the above Examples and Comparative Examples, and left to cure at a temperature of 20 ° C. and a humidity of 60% for 28 days. After curing, a cut was made in the surface of the heat insulating layer 1 to divide the followability evaluation portion 1a having an area of 150 × 50 mm from the surplus portion 1b to prepare a test body for a crack followability test. 5 mm in the direction of the arrow in FIG.
A tensile test was performed at a tensile speed of / min to measure the following crack width when a pinhole or break occurred in the following portion 1a of the heat insulating layer.

[0048]

[Table 1]

As can be seen from Table 1, the thermal conductivity coefficient is 500
In Examples 1 to 3 in which a heat insulating layer of Kcal / m ² · h · ° C. or less was formed, the decrease in bending strength was suppressed to less than 10% of that at room temperature even immediately after standing at a high temperature. The reinforcing effect by the reinforced resin layer is sufficiently maintained. Further, since these heat insulating layers have a high ability to follow cracks and are excellent in waterproofness, they have an effect of preventing the epoxy resin of the fiber reinforced resin layer from deteriorating. On the other hand, in Comparative Example 1 in which only the overcoating material coating layer was provided on the fiber-reinforced resin layer and Comparative Examples 2 and 3 in which the heat insulating property of the heat insulating layer was small, the bending strength was significantly lower than at room temperature. . In Comparative Example 3 in which the solar absorptivity of the topcoat material coating layer was high, the decrease in bending strength was more remarkable than in Comparative Example 2. In addition, Comparative Examples 1 to 3 all had insufficient crack followability and lacked waterproofness.

The present invention is not limited to those shown in the above embodiments, but various conditions can be changed within the scope of the present invention depending on the purpose and application.

[0051]

According to the method for protecting a concrete structure of the present invention, a coating layer having a high heat insulating property is formed on the surface of the fiber reinforced resin layer to suppress a rise in the temperature of the fiber reinforced resin layer. Softening of the resin to be formed can be prevented and the reinforcing effect can be reliably exhibited. When the solar absorptivity of the outermost surface of the heat insulating layer is equal to or less than a predetermined value, the effect of suppressing the temperature rise of the fiber reinforced resin layer is further increased.
When the heat insulating layer is a fiber layer, a heat insulating layer having a low heat conductivity can be easily formed. And
When the heat insulation layer is an acrylic rubber coating film layer, the water vapor permeability and waterproofness of the coating film prevent the fiber reinforced resin layer from being deteriorated by moisture, so that the strength of the fiber reinforced resin layer is reduced. The effect of keeping is even higher.

[Brief description of the drawings]

FIG. 1 shows an epoxy resin obtained by curing bisphenol A at room temperature with various ethylenediamine-based curing agents.
It is a characteristic view which shows the relationship between temperature and tensile strength.

2A and 2B show a test body for a crack followability test, wherein FIG. 2A is a plan view and FIG. 2B is a side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat insulation layer 1a Followability evaluation part 1b Surplus part 2 Slate plate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshito Uramoto 1-Funamicho, Minato-ku, Nagoya-shi, Aichi F-term in Nagoya Research Laboratory, Toagosei Co., Ltd. F-term (reference) 2E001 DA01 DD01 EA01 FA04 GA06 GA24 GA26 GA27 GA28 HA33 HA34 HD11 HD12 HD13 HE01 JA21 JA22 JA28 JA29 JB07 JD02 JD04 JD05 2E176 AA01 BB03 BB29 4G028 FA01

Claims (4)

[Claims] At least one heat-insulating layer having a thermal conductivity of 500 Kcal / m ² · h · ° C. or less is formed on the surface of a fiber-reinforced resin layer of a concrete structure reinforced by a fiber-reinforced resin layer provided on the surface. A method for protecting a concrete structure, further comprising forming an overcoat material coating layer on the heat insulating layer as necessary. 2. The method for protecting a concrete structure according to claim 1, wherein the solar radiation absorptivity of the outermost surface of the heat insulating layer or the surface of the top coat layer is 0.5 or less. 3. The method for protecting a concrete structure according to claim 1, wherein the heat insulating layer is an acrylic rubber coating layer. 4. The method for protecting a concrete structure according to claim 1, wherein the heat insulating layer is a fiber layer.