Surface protection structure for concrete structures and surface protection method for concrete structures

Abstract

This invention provides a surface protection structure and a surface protection method for concrete structures that can achieve both fire resistance and self-extinguishing properties to prevent the spread of fire in the event of a fire, and the ability to withstand the opening and closing loads of cracks. [Solution] The surface protection structure for concrete structures comprises a primer layer consisting of a primer formed on the surface of the concrete structure, and a main material layer consisting of a resin-based paint formed on the primer layer, wherein the primer layer has a film thickness of 45 μm or more and 625 μm or less, and the main material layer has a film thickness of 125 μm or more and 705 μm or less, and the flame extinction time is 30 seconds or less in the NEXCO Test Method 738 Tunnel Repair Material Flammability Test Method, the distance between the tip of the fire caused by combustion and the ignition point is less than 600 mm, and the fatigue resistance standard in the Tokaido Shinkansen Reinforced Concrete Structure Maintenance and Management Standards is also met.

Description

Technical Field

[0001] The present invention relates to a surface protection structure for a concrete structure and a surface protection method for a concrete structure. In particular, in a part where a building, a facility, etc. are installed at the lower part, such as a concrete viaduct and a tunnel, which require fire resistance and self-extinguishing properties, the present invention relates to a surface protection method having fire resistance and self-extinguishing properties.

Background Art

[0002] Concrete structures may crack due to the influence of load during vehicle passage, corrosion of internal steel bars, and alkali-aggregate reaction. From these cracks, deterioration factors such as moisture and chloride ions penetrate into the concrete, accelerating the deterioration of the concrete structure. Therefore, measures are taken to apply paint to the surface of the concrete structure to form a protective coating film.

[0003] On the other hand, it is known that when a concrete structure deflects due to heavy traffic or the like, the cracks generated in the concrete structure open and close. In contrast, in order to have the performance of blocking deterioration factors and following the opening and closing of cracks, the intermediate coating of the main material layer in the conventional coating film is designed to be 400 μm or more. As shown in Non-Patent Document 1, when the film thickness of the intermediate coating of the main material layer of the protective coating film is formed thin during construction, it cannot follow the opening and closing load of the cracks generated in the concrete structure, so the coating film is likely to crack or peel, and there is a problem that the function as a protective coating film deteriorates. Therefore, in recent years, as shown in Patent Document 1, a method for forming a flexible coating film having crack followability for a concrete structure has been developed.

[0004] Patent Document 1 describes a crack detection structure capable of detecting cracks in a structure, which includes a light-guiding inelastic resin layer containing a light-collecting fluorescent paint formed on the surface of the structure, and a light-transmitting elastic resin layer formed on the surface of the inelastic resin layer.

Prior Art Documents

[0005] [Non-Patent Document 1] Field survey on the soundness of existing surface protection work, JCI2017, No.1, Vol.39 [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2005-35827 [Overview of the project] [Problems that the invention aims to solve]

[0007] On the other hand, concrete structures such as elevated bridges and tunnels, on which buildings and facilities are installed, require fire resistance and self-extinguishing properties to prevent fire from spreading in the event of a fire. For such concrete structures, it is necessary to implement surface protection methods that achieve both fire resistance and self-extinguishing properties to prevent fire from spreading in the event of a fire, and the ability to withstand the opening and closing loads of cracks.

[0008] However, the technology disclosed in Patent Document 1 does not take into consideration preventing concrete structures from spreading fire in the event of a fire. Therefore, the technology disclosed in Patent Document 1 has the problem that it cannot achieve both fire resistance and self-extinguishing properties, which are necessary to prevent fire from spreading in the event of a fire, and the ability to withstand the opening and closing loads of cracks.

[0009] Therefore, the present invention was devised in view of the above-mentioned problems, and its objective is to provide a surface protection structure and a surface protection method for concrete structures that can achieve both performance that prevents fire from spreading in the event of a fire, such as fire resistance and self-extinguishing properties, and performance that can withstand the opening and closing load of cracks. [Means for solving the problem]

[0010] The surface protection structure for concrete structures according to the first invention comprises a primer layer consisting of a primer formed on the surface of the concrete structure, and a main material layer consisting of a resin-based paint formed on the primer layer, wherein the primer layer has a film thickness of 45 μm or more and 625 μm or less, and the main material layer has a film thickness of 125 μm or more and 705 μm or less, and the flame extinction time is 30 seconds or less in the NEXCO Test Method 738 Tunnel Repair Material Flammability Test Method, the distance between the leading edge of the fire caused by combustion and the ignition point is less than 600 mm, and the fatigue resistance standards in the Tokaido Shinkansen Reinforced Concrete Structure Maintenance and Management Standards are met.

[0011] The surface protection structure for concrete structures according to the second invention is characterized in that, in the first invention, the tensile strength of the coating film formed by the resin-based paint is 5 N / mm². 2 The above is true, and it is characterized by having an elongation of 300% or more.

[0012] The surface protection structure for concrete structures according to the third invention is characterized in that, in the first invention, the resin-based coating is an aqueous polyurethane resin-based coating.

[0013] The surface protection structure for concrete structures according to the fourth invention is characterized in that, in the first invention, the resin-based coating is a one-component type.

[0014] The surface protection structure for concrete structures according to the fifth invention is characterized in that, in the first invention, the primer is an epoxy resin.

[0015] The surface protection method for concrete structures according to the sixth invention comprises a first step of forming a primer layer made of a primer on the surface of a concrete structure, and a second step of forming a main material layer made of a resin-based paint on the primer layer, wherein the primer layer has a film thickness of 45 μm or more and 625 μm or less, and the main material layer has a film thickness of 125 μm or more and 705 μm or less, and the surface protection structure made of the primer layer and the main material layer is characterized in that, in the NEXCO Test Method 738 Tunnel Repair Material Flammability Test Method, the flame extinction time is 30 seconds or less, the distance between the tip of the fire caused by combustion and the ignition point is less than 600 mm, and the fatigue resistance standard in the Tokaido Shinkansen Reinforced Concrete Structure Maintenance and Management Standards is met. [Effects of the Invention]

[0016] According to Inventions 1 through 6, the surface protection structure and surface protection method for concrete structures have a primer layer with a film thickness of 45 μm or more and 625 μm or less, and a main material layer with a film thickness of 125 μm or more and 705 μm or less. Furthermore, the surface protection structure and surface protection method for concrete structures meet the NEXCO Test Method 738 (Flame Spread Test Method for Tunnel Repair Materials), where the flame extinguishing time is 30 seconds or less, the distance between the leading edge of the fire caused by combustion and the ignition point is less than 600 mm, and the fatigue resistance standards of the Tokaido Shinkansen Reinforced Concrete Structure Maintenance Standards. This makes it possible to achieve both performance that prevents the spread of fire in the event of a fire, such as fire spread resistance and self-extinguishing properties, and performance that can withstand the opening and closing load of cracks.

[0017] In particular, according to the second invention, the surface protection structure for concrete structures has a coating film formed by a resin-based paint with a tensile strength of 5 N / mm². 2 Furthermore, it exhibits an elongation of over 300%. This makes it possible to form a flexible yet strong coating film.

[0018] In particular, according to the third invention, the resin-based coating is a water-based polyurethane resin-based coating. This makes it possible to suppress VOC emissions, shorten the flame extinction time, and form a flexible yet tough coating film.

[0019] In particular, according to the fourth invention, the surface protection structure of the concrete structure has a one-component resin-based paint. As a result, metering and mixing agitation are not required, enabling more efficient construction.

[0020] In particular, according to the fifth invention, the surface protection structure of the concrete structure has an epoxy resin primer. This makes it possible to form a primer layer with excellent adhesion to the concrete structure and excellent performance in blocking deterioration factors.

Brief Description of the Drawings

[0021] [Figure 1] FIG. 1 is a perspective view showing an example of the surface protection structure of the concrete structure in the present embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the surface protection structure of the concrete structure in the present embodiment.

Modes for Carrying Out the Invention

[0022] An example of the surface protection structure 2 in the present embodiment will be described while referring to the drawings.

[0023] FIG. 1 is a perspective view showing a state where the surface protection structure 2 according to the embodiment is formed on the surface of the concrete structure 1.

[0024] The concrete structure 1 is a concrete structure such as a building or a bridge made of concrete or metal, or a working device made of metal or resin, etc., where the occurrence of cracks due to aging deterioration is assumed. Structures such as concrete elevated bridges and tunnels where buildings and facilities are installed at the lower part are preferred, but it is not limited thereto, and any concrete structure may be used.

[0025] ​​

[0026] The formation of this surface protection structure 2 is not limited to the construction or manufacture of the concrete structure 1, but may also occur after the concrete structure 1 has been put into use. Furthermore, the formation of the surface protection structure 2 is carried out by sequentially applying the primer layer 21 and the main material layer 22 to the concrete structure 1.

[0027] The primer layer 21 is formed using a resin such as epoxy resin, acrylic resin, or urethane resin as a base material, which has excellent adhesion to the concrete structure 1 and excellent performance in blocking deterioration factors, but is not limited to this and may be formed from any primer.

[0028] As shown in Figure 2, the primer layer 21 preferably has a film thickness a of 45 μm or more and less than 350 μm, but is not limited to this, and may be 45 μm or more and 625 μm or less.

[0029] The main material layer 22 is formed using a water-based paint as the base material for environmental adaptability. Alternatively, the main material layer 22 may be formed using a one-component paint as the base material for ease of application. Furthermore, the main material layer 22 may be formed using a resin-based paint such as urea resin, urethane resin, silicone resin, or acrylic silicone resin as the base material. The main material layer 22 may also be formed using a water-based polyurethane resin paint with low VOC emissions as the base material. Additionally, the main material layer 22 may be formed using a urethane resin, which is known for its short flame extinction time, as the base material. Moreover, the main material layer 22 is not limited to these and may be formed using any main material. Furthermore, since the main material layer 22 needs to withstand crack opening and closing loads even with a thin film thickness, the tensile strength of the coating film must be 5 N / mm². 2 A coating film that meets the above criteria and has an elongation of 300% or more is preferred. These test methods may be measured according to, for example, JIS K 5400-1990.

[0030] The main material layer 22 preferably has a film thickness b of 125 μm or more and less than 450 μm, but is not limited to this, and may be 125 μm or more and 705 μm or less.

[0031] Next, the method for applying the surface protection structure 2 to the concrete structure 1 in this embodiment will be described. First, in the first step, a primer is applied to the surface of the concrete structure 1 to form a primer layer 21. In this case, the primer may be applied to the surface of the concrete structure 1 with a brush or the like, but it is not limited to this, and may also be applied using methods such as trowel application, roller application, or spray application.

[0032] Next, in the second step, a water-based polyurethane resin paint is applied to the primer layer 21 to form the main material layer 22. In this case, the water-based polyurethane resin paint may be applied to the primer layer 21 with a brush or the like, but it is not limited to this method, and may also be applied using methods such as trowel application, roller application, or spray application.

[0033] The above-described process completes the application of the surface protection structure 2 to the concrete structure 1 in this embodiment. Furthermore, the application of the surface protection structure 2 in this embodiment is not limited to the above-described method and procedure, but may be carried out by any method and procedure. [Examples]

[0034] Next, an example of a surface protection structure 2 to which this embodiment is applied will be described, but the present invention is not limited to these examples.

[0035] In the painting process of this example, Neo Primer EX (manufactured by Showbond Material Co., Ltd.) was used for the primer layer 21, and Neo Liner EX (manufactured by Showbond Material Co., Ltd.) was used for the main material layer 22. Neo Primer EX is an epoxy resin-based primer, and Neo Liner EX is a one-component, water-based polyurethane resin-based paint. The tensile strength of the Neo Liner EX coating film is 5 N / mm². 2The above is true, and the elongation is 300% or more. In the examples, the application amounts of the primer layer 21 and the main material layer 22 were changed, and the self-extinguishing properties, fire spread properties, and fatigue resistance of surface protection structures 2 with different film thicknesses after curing were evaluated. The results of the examples are shown in Table 1. Comparative Examples 1, 2, 3, and 4 in Table 1 are comparative examples to the examples of surface protection structures 2 to which this embodiment is applied. [Table 1]

[0036] In this study, the self-extinguishing properties and fire spread resistance were determined according to NEXCO Test Method 738, Fire Spread Resistance Test Method for Tunnel Repair Materials. The flame extinguishing time of the surface protection structure 2 and the distance reached by the leading edge of the fire from the ignition point were measured. In this measurement, self-extinguishing properties were judged as ○ if the flame extinguishing time was 30 seconds or less, and × if the flame extinguishing time exceeded 30 seconds. Fire spread resistance was judged as ○ if the leading edge of the fire from the fire reached less than 600 mm from the ignition point, and × if it reached 600 mm or more.

[0037] Fatigue resistance was tested according to the fatigue resistance test method in the Tokaido Shinkansen reinforced concrete structure maintenance and management standards. A ○ was used if the test met the fatigue resistance standards in the Tokaido Shinkansen reinforced concrete structure maintenance and management standards, and a × was used if it did not. The fatigue resistance test method involved setting up a specimen so that the crack width was 0.2 mm, and performing a movement of 0.04 mm with a period of 0.1 seconds for 6 million times at 20°C, 6 million times at 60°C, and 6 million times at -10°C, for a total of 18 million movements. After this, the specimen was statically pulled until the crack width increased by 0.12 mm, and the cracking and rupture of the coating was checked. In this test, a ○ was used if no cracking or rupture of the coating was observed, and a × was used if it was observed.

[0038] As shown in Table 1, it was found that when the thickness of the primer layer 21 is 45 μm or more and 625 μm or less, and the thickness of the main material layer 22 is 125 μm or more and 705 μm or less, the self-extinguishing properties, fire spread resistance, and fatigue resistance meet the standards.

[0039] The surface protection structure 2 according to this embodiment has been described above. In the surface protection structure 2 according to this embodiment, the thickness a of the primer layer 21 is 45 μm or more and 625 μm or less, and the thickness b of the main material layer 22 is 125 μm or more and 705 μm or less. This makes it possible to achieve both performance that prevents the spread of fire in the event of a fire, such as fire spread resistance and self-extinguishing properties, and performance that can withstand the opening and closing load of cracks.

[0040] The surface protection structure 2 according to this embodiment has a coating film formed by a resin-based paint with a tensile strength of 5 N / mm². 2 Furthermore, it exhibits an elongation of over 300%. This makes it possible to form a flexible yet strong coating film.

[0041] Furthermore, the surface protection structure 2 according to this embodiment is a water-based polyurethane resin coating. This makes it possible to form a surface protection structure 2 that is adapted to the shift from solvent-based to water-based coatings, which has been required in recent years due to the trend towards stricter VOC (Volatile Organic Compounds) regulations and the rapidly increasing environmental awareness in society. In addition, because a urethane resin is used, it is possible to shorten the time it takes for a fire to spread.

[0042] The surface protection structure 2 according to this embodiment uses a one-component resin-based coating. This eliminates the need for measuring and mixing / stirring, making application more efficient.

[0043] In this embodiment, the surface protection structure 2 uses an epoxy resin as the primer. This makes it possible to form a primer layer 21 with excellent adhesion to the concrete structure 1 and excellent performance in blocking deterioration factors.

[0044] The surface protection structure 2 according to this embodiment has a flame extinguishing time of 30 seconds or less and a distance of less than 600 mm between the leading edge of the fire and the ignition point in NEXCO Test Method 738, a test method for the spread of fire in tunnel repair materials, and also satisfies the fatigue resistance standards in the maintenance and management standards for reinforced concrete structures of the Tokaido Shinkansen. This makes it possible to achieve both performance that prevents fire from spreading in the event of a fire, such as fire resistance and self-extinguishing properties, and performance that can withstand the opening and closing load of cracks.

[0045] While embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0046] 1. Concrete structures 2 Surface protection structure 21 Primer layer 22 Main material layer

Claims

1. A primer layer consisting of a primer formed on the surface of a concrete structure, The system comprises a main material layer made of a resin-based coating formed on the primer layer, The primer layer has a film thickness of 45 μm or more and 625 μm or less. The main material layer has a film thickness of 125 μm or more and 705 μm or less. In the NEXCO Test Method 738, the fire spread test method for tunnel repair materials, the extinction time is 30 seconds or less, the distance between the leading edge of the fire caused by combustion and the ignition point is less than 600 mm, and the fatigue resistance standards in the Tokaido Shinkansen reinforced concrete structure maintenance standards are met. A surface protection structure for concrete structures characterized by the following.

2. The tensile strength of the coating film formed by the aforementioned resin-based paint is 5 N / mm² 2 The above conditions must be met, and the growth rate must be 300% or more. A surface protection structure for a concrete structure according to claim 1, characterized by the above.

3. The aforementioned resin-based coating is a water-based polyurethane resin-based coating. A surface protection structure for a concrete structure according to claim 1, characterized by the above.

4. The aforementioned resin-based coating is a one-component type. A surface protection structure for a concrete structure according to claim 1, characterized by the above.

5. The primer is an epoxy resin. A surface protection structure for a concrete structure according to claim 1, characterized by the above.

6. A first step of forming a primer layer consisting of a primer on the surface of a concrete structure, The process includes a second step of forming a main material layer made of a resin-based coating on the primer layer, The primer layer has a film thickness of 45 μm or more and 625 μm or less. The main material layer has a film thickness of 125 μm or more and 705 μm or less. The surface protection structure consisting of the primer layer and the main material layer meets the following criteria: the flame extinction time is 30 seconds or less in the NEXCO Test Method 738 (Flame Spread Test Method for Tunnel Repair Materials), the distance between the leading edge of the fire caused by combustion and the ignition point is less than 600 mm, and the fatigue resistance criteria in the Tokaido Shinkansen Reinforced Concrete Structure Maintenance and Management Standards. A surface protection method for concrete structures characterized by the following features.

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