JP6579932B2 - Stripping prevention method - Google Patents

Description

  The present invention relates to a peeling prevention method for forming a resin composition layer on the surface of a structure having a water-absorbing inorganic material surface such as a concrete structure to prevent peeling from the surface of the structure.

  Conventionally, various measures have been proposed in order to prevent an accident in which a concrete piece is peeled off from the surface of a concrete structure such as a viaduct or a tunnel and a party and a third party are damaged. A conventional method for preventing a peeling accident from a structure is generally to bond a fiber material to the surface of the concrete structure in order to make up for the weak point that the concrete is weak against tensile stress.

  In such a conventional peeling prevention method, (1) a primer is applied to the surface of a structure. (2) Apply putty to smooth the surface of the structure. (3) Applying an impregnation adhesive to impregnate a fiber sheet made of fiber material. (4) A fiber sheet is stuck on the impregnated adhesive. (5) Further, an impregnation adhesive is applied on the fiber sheet to impregnate the fiber sheet with the adhesive. It requires a lot of work, and it takes time for the fiber sheet to be impregnated with adhesive, and it must be held overhead, which is labor intensive and labor costs increase. There was a problem that the cost had to be high. In addition, since the adhesive is not transparent, the state of the surface of the structure cannot be visually recognized, and there has been a problem that countermeasures are delayed because initial water leakage and cracks cannot be found.

  For example, in Patent Document 1, for the purpose of accurately positioning with a drill with high safety, after temporarily arranging the grid-like reinforcing member 5 formed of fiber reinforced resin on the bottom surface of the concrete bridge, Concrete that forms a covering layer 9 that covers the grid-like reinforcing member 5 after fixing the grid-like reinforcing member 5 to the lower surface of the concrete bridge while applying tension in the plane direction to the grid-like reinforcing member 5 by the fixture 6. A method of reinforcing a bridge is disclosed (see claim 1 of patent document 1, paragraphs [0021] to [0033] of the specification, FIGS. 2 and 3 of the drawings, etc.).

  However, as described above, the method for reinforcing a concrete bridge described in Patent Document 1 has a large number of steps, which inevitably requires a long construction time, and the cost of countermeasures increases. The problem of not being able to see is not solved.

  Patent Document 2 contains an isocyanate group-containing urethane prepolymer (A) and a thixotropic agent (B) for the purpose of being excellent in coating workability and weather resistance and capable of visually diagnosing deterioration of concrete. Further, there has been disclosed a method for preventing exfoliation in which a one-component polyurethane resin composition for preventing delamination of concrete pieces and tiles is used, and a reinforcing layer including a resin coating film composed thereof is formed on the surface of a concrete structure (see Patent Document 2) (See claim 8 of claims, paragraphs [0076] to [0079] etc. of the specification).

  However, although the peeling prevention method described in Patent Document 2 can visually confirm the deterioration diagnosis of the surface of the concrete structure, it requires a step of applying a primer and a step of impregnating a fiber material. There is no difference from the conventional peeling prevention method, and it has not been possible to solve the problems of reducing the number of processes and shortening the construction time.

  Moreover, in order to reduce the man-hour at the time of construction of peeling prevention work, the peeling prevention construction method which applies a transparent urethane type resin directly to a concrete surface is also proposed. However, the urethane-based resin is inferior in alkali resistance and has a problem in durability over time when applied directly to a concrete surface.

JP-A-9-59937 JP 2011-252292 A

  Accordingly, the present invention has been devised in view of the above-mentioned problems, and its object is to prevent the peeling from the structure by forming a high-strength resin film in one process with a small number of work steps. In addition, an object of the present invention is to provide a peeling prevention method that is environmentally friendly with little material loss, and the resin film is transparent and the structure surface can be visually observed even after construction.

  The peeling prevention method according to claim 1 is a peeling prevention method for forming a film of a resin composition on a surface of a structure having a water-absorbing inorganic material to prevent peeling from the surface of the structure. Is a mixture of a urethane acrylate resin and / or an epoxy acrylate resin and a thickener mixed with a two-pack type epoxy resin composed of an epoxy resin and a curing agent, and without applying a primer, Only by forming a film of the resin composition without bonding, peeling from the surface of the structure is prevented.

  The peeling prevention method according to claim 2 is the peeling prevention method according to claim 1, wherein the film of the resin composition exhibits a displacement of 10 mm or more in a punching test, and the punching load at that time is It is characterized by being 300N or more.

  The peeling prevention method according to claim 3 is the peeling prevention method according to claim 1 or 2, wherein the film of the resin composition is transparent.

  According to the invention described in claims 1 to 3, since the resin composition is a two-pack type epoxy resin composed of an epoxy resin and a curing agent, it is strong in alkalinity, like a conventional primer, such as a concrete structure. Even if it is applied directly to the surface, the adhesion to the surface of the structure is good. Moreover, since the resin composition contains a urethane acrylate resin and / or an epoxy acrylate resin and a thickening agent, in addition to the strength derived from the epoxy resin, the resin layer has a higher viscosity than the conventional epoxy resin and the thickness of the resin layer. In addition to the required strength, primer application, putty application, fiber sheet application, etc. are not required, and man-hours are reduced and a high-strength resin film is formed in one step to prevent peeling from the structure. Can do. In addition, since the only material used is a resin composition, inventory management and calculation of the amount used can be simplified, material loss can be reduced, and it can be made environmentally friendly.

  In particular, according to the invention described in claim 2, since the coating of the resin composition shows a displacement of 10 mm or more in the punching test, and the punching load at that time is 300 N or more, it is performed in one step. Further, it becomes possible to form a high-strength resin film, and it is possible to make it highly durable with little deterioration over time.

  In particular, according to the invention described in claim 3, the surface of the structure can be visually observed even after the construction, and the deterioration diagnosis of the surface of the structure is easy at the time of periodic inspection. For this reason, maintenance maintenance costs, such as a periodic inspection, can be reduced.

It is a graph which shows the punching test result of the coating film of the resin composition which concerns on this embodiment. It is a photograph which shows the base treatment process of the peeling prevention construction method concerning this embodiment. It is a photograph which shows the adhesive agent coating process of the peeling prevention construction method concerning this embodiment. It is a photograph which shows the completion state of the peeling prevention construction method concerning this embodiment.

  Hereinafter, a peeling prevention method according to an embodiment of the present invention will be described with reference to the drawings.

[Resin composition]
First, the resin composition used for the peeling prevention method according to this embodiment will be described. The resin composition according to the present embodiment is a composition in which a two-component epoxy resin composed of an epoxy resin and a curing agent is a main component, and a urethane (meth) acrylate resin and a thickener are added thereto.

  However, the resin composition according to the present invention may add an epoxy (meth) acrylate resin instead of the urethane acrylate resin, or may add both a urethane acrylate resin and an epoxy acrylate resin.

(Epoxy resin)
The kind of epoxy resin which is the main ingredient of the resin composition according to the present invention is not particularly limited, and various types can be used. For example, bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; alicyclic epoxy resins such as hydrogenated bisphenol A type epoxy resin and hydrogenated bisphenol AD type epoxy resin; dihydroxynaphthalene type epoxy resin; A dihydric phenol type epoxy resin such as an epoxy resin derived from butylcatechol and epuihalohydrin; a monoepoxy compound from a monohydric phenol; neopentyl glycol, trimesylolpropane, 1,6-hexanediol, 1, An alcohol ether type epoxy resin composed of a monovalent or polyhydric alcohol such as 4-butanediol can be used. Further, a plurality of the plurality of resins may be used in combination.

(Curing agent)
The kind of the curing agent contained in the resin composition according to the present invention is not particularly limited as long as it can cure the aforementioned epoxy resin. For example, an organic compound containing a functional group such as a carboxylic anhydride group, a carboxyl group, a carboxylic acid hydrazide group, an amino group, a hydroxyl group, or a mercapto group can be used. Of course, the curing agent may be a mixture of a plurality of types of materials.

(Urethane acrylate resin)
The urethane acrylate resin contained in the resin composition according to the present invention is not particularly limited. For example, an isocyanate-terminated polyester or an isocyanate-terminated polyol and a functional group-containing acrylic monomer, or acrylic acid or methacrylic acid. A urethane acrylate resin obtained by reacting with hydroxyethyl (meth) acrylate or the like can be used.

(Epoxy acrylate resin)
The epoxy acrylate resin contained in the resin composition according to the present invention is not particularly limited. For example, the addition of a bisphenol type epoxy resin and an ethylenically unsaturated carboxylic acid, or acrylic acid or methacrylic acid. Or an adduct and an ethylenically unsaturated polyvalent carboxylic acid anhydride, or a reaction product of maleic anhydride, itaconic anhydride, or the like can be used.

(Thickener)
Examples of the thickener contained in the resin composition according to the present invention include inorganic types such as dry silica and bentonite, and organic types such as amide wax and hydrogenated castor oil. May be. However, dry silica is suitably used from the viewpoint of ensuring the transparency of the coating film of the resin composition. However, if a large amount of dry silica is added, the transparency of the coating film of the resin composition is lost. Therefore, it is appropriately adjusted while confirming the state of thickening and thixotropy.

  Further, the cured coating film (film) of the resin composition according to the present embodiment exhibits a displacement of 10 mm or more in a punching test, and the punching load at that time is 300 N or more, preferably punching The load is 1500 N or more.

  The punching test was conducted by a punching test prescribed by the former Japan Highway Public Corporation (East Japan Expressway Co., Ltd., Central Japan Expressway Co., Ltd., West Japan Expressway Co., Ltd.). Specifically, the push-out test was conducted at the center of the back side of the type 300 (40 x 60 x 6 cm) of the upper lid U-shaped side groove (lid) specified in JIS A 5372 Annex 5, A cut was made with a core cutter for concrete at a depth of cm, and the surface was subjected to keren treatment, and then the resin composition according to this embodiment was applied to form a coating film to obtain a specimen. After curing for 7 days, using an Amsler universal testing machine, load was applied until the coating film of the resin composition was ruptured and punched out, and the displacement at that time and measurement of the punching load, which was the maximum load, were performed. did.

  FIG. 1 is a graph plotting the test results of the coating film of the resin composition according to this embodiment by this punching test. In this graph, the vertical axis is the punching load (N), and the horizontal axis is the displacement ( mm). As shown in FIG. 1, the coating film of the resin composition according to the present embodiment shows a displacement of about 13 mm, and the punching load at that time is 1900 N or more.

  The test result of the push-out test shown in FIG. 1 is a satisfactory value as compared with a conventional fiber material such as a fiber sheet, and it is considered that the function of the fiber sheet can be replaced with a coating film of a resin composition. However, from the viewpoint of preventing peeling from the surface of the structure, it is sufficient that the push-out load (N) of the coating film of the resin composition according to the present invention is 300 N or more, and preferably 1500 N or more. . In short, it is only necessary that the coating film after the resin composition according to the present invention is cured (after being in a coating state) has a certain elongation (flexibility) and strength.

  On the other hand, the conventional hard epoxy resin does not satisfy the above-mentioned displacement and the punching load in such a punching test, and the conventional soft epoxy resin satisfies the displacement but the punching load is 300N. Never exceed.

  That is, as described above, the coating film (film) of the resin composition according to this embodiment is mainly composed of a two-pack type epoxy resin, and a urethane acrylate resin and / or an epoxy acrylate resin and a thickener are added. It is considered that the composition exhibits physical properties that can simultaneously achieve a displacement of 10 mm or more and a punching load of 300 N or more in the punching test.

  And the coating film (film | membrane) of the resin composition which concerns on this embodiment has the required thickness since the raw material resin is transparent and the quantity of the thickener is adjusted as mentioned above. It is transparent as a whole. For this reason, even if the coating film of the resin composition is formed on the surface of the structure, the surface of the structure can be visually observed.

[Peeling prevention method]
Next, the peeling prevention construction method according to the embodiment of the present invention will be described.

  The structure to which the peeling prevention method according to the present invention can be applied is a concrete structure, a structure whose surface is made of mortar, a brick structure or a block structure. In short, the peeling prevention method according to the present invention can be applied to a structure having a water-absorbing inorganic material on the surface. Specifically, the peeling prevention method according to the present invention can be suitably applied to the surface of a structure such as a railway or highway tunnel, a wall surface of a lower structure of a bridge, or a lower surface of a main girder of a bridge.

  The exfoliation preventing method according to the embodiment of the present invention forms a film of the resin composition on the surface of a structure having such a water-absorbing inorganic material (in the photograph, a tunnel that is a concrete structure is illustrated), This is a method for preventing peeling from the surface of the structure, and has the following steps.

(1) Ground treatment process First, in the peeling prevention method according to the present embodiment, as shown in the photograph of FIG. 2, as in the conventional peeling prevention method, repairing a large cross-sectional defect on the structure surface, If necessary, a ground treatment process is performed to perform ground treatment on the surface of the structure, which is a construction range of the peeling prevention work as necessary.

(2) Adhesive application process Next, in the peeling prevention construction method according to the present embodiment, as shown in the photograph of FIG. 3, the resin composition according to the present embodiment as an adhesive is applied to the surface of the structure that is the construction range. An adhesive application step of applying the object with a brush or scissors is performed.

  Instead of applying the resin composition with a brush or scissors, the resin composition according to the above-described embodiment may be sprayed or sprayed. In short, in this step, if the resin layer made of the resin composition according to the embodiment can be laminated on the surface of the structure within a predetermined range and a film can be formed after curing, the means for forming the resin layer is not limited. Absent.

  In this step, as described above, a composition to which a urethane acrylate resin (epoxy acrylate resin) and a thickener are added is used. Excellent workability.

  On the other hand, in the conventional peeling prevention method, as described above, five steps including a primer coating step, a putty coating step, an impregnation adhesive coating step, a fiber sheet sticking step, and an impregnation adhesive coating step are required. In other words, the primer coating process and the putty coating process were separated because the primer, that is, the drug to be applied first, has good compatibility with the concrete structure, that is, it has high alkali resistance and adhesion to concrete. This is because the epoxy resin was selected only because it was good. That is, the conventional epoxy resin is in a liquid state at normal temperature, and it is because the resin agent itself cannot have a putty-like thickness.

  In addition, the impregnation adhesive application process, the fiber sheet sticking process, and the impregnation adhesive application process were required because the strength of peeling prevention was dependent on the tensile stress of the fiber material, so the fiber material was firmly bonded From the necessity, an ultraviolet curable resin or the like that is cured by a radical reaction was selected, and it was inevitably divided into three steps because of the necessity of impregnating the fiber material with the resin.

  On the other hand, in the peeling prevention method according to the present embodiment, as described above, the resin composition applied to the structure forms a film having high strength and a predetermined elongation (flexibility). In addition to the need for the fiber sheet sticking step, the impregnation adhesive application step and the impregnation adhesive application step can be omitted.

(3) Completion Then, as shown in the photograph of FIG. 4, if a predetermined curing period in which the resin composition forms a coating film is set, the exfoliation preventing work work by the exfoliation preventing method according to the present embodiment is completed.

  Here, in the exfoliation preventing method according to the present embodiment, as shown in the photograph of FIG. 4, since the coating film (film) of the completed resin composition is transparent, the surface of the structure can be visually observed. Yes. For this reason, it is not necessary to hit the structure with a test hammer to diagnose the condition of the structure, or to check it at a close position using an aerial work vehicle, enabling visual diagnosis from a distance, such as periodic inspections. Maintenance costs can be reduced.

  On the other hand, in the conventional peeling prevention method, since a colored resin is used, the coating film is naturally colored, and visual observation is difficult. Moreover, in the peeling prevention method of the above-mentioned patent document 2, since the one-component type polyurethane resin composition containing an isocyanate group-containing urethane prepolymer (A) and a thixotropic agent (B) is used, alkali resistance However, the adhesion to concrete structures is problematic, and there is concern about durability.

  According to the peeling prevention method according to the present embodiment described above, since an epoxy resin excellent in alkali resistance is used, the structure can be directly applied to the surface of a structure having a water-absorbing inorganic material such as a concrete structure. Good adhesion to the surface. In addition, the resin composition according to the present embodiment forms a highly durable coating film excellent in displacement and load resistance. Can do. In addition, since the resin composition contains a urethane acrylate resin and / or an epoxy acrylate resin and a thickener, in addition to the strength derived from the epoxy resin, the resin layer has a higher viscosity than the conventional epoxy resin and the thickness of the resin layer. In addition to the required strength, there is no need for primer application, putty application, fiber sheet application, etc., and it reduces man-hours and forms a high-strength resin film in one step to prevent peeling from the structure. be able to. In addition, the material used is only the resin composition, inventory management and calculation of the amount used are simple, and there is little material loss, and it can be made environmentally friendly.

  As described above, the peeling prevention method according to the embodiment of the present invention has been described in detail, but the above-described or illustrated embodiment is merely an embodiment that is embodied in carrying out the present invention. Therefore, the technical scope of the present invention should not be construed in a limited manner. In particular, the concrete structure is mainly exemplified as the structure, but the present invention can be applied to a structure having a water-absorbing inorganic material on the surface, such as a brick structure or a block structure. . This is because mortar is used for the joint portion even in the case of brick construction or block construction, and the resin composition and the peeling prevention method according to the present invention which are durable against alkalinity can be suitably used.

Claims (3)

A peeling prevention method for forming a resin composition film on the surface of a structure having a water-absorbing inorganic material and preventing peeling from the surface of the structure,
The resin composition is obtained by mixing a urethane acrylate resin and / or an epoxy acrylate resin and a thickener in a two-pack type epoxy resin composed of an epoxy resin and a curing agent,
A peeling prevention method characterized in that peeling from the surface of the structure is prevented only by forming a film of the resin composition without applying a primer and without adhering a fiber material. The peeling prevention method according to claim 1, wherein the coating of the resin composition exhibits a displacement of 10 mm or more in a punching test, and a punching load at that time is 300 N or more. The peeling prevention method according to claim 1 or 2, wherein the coating film of the resin composition is transparent.