Methods for protecting reinforced concrete structures

Abstract

To provide a protection method of a reinforced concrete structure capable of forming a protective layer on the reinforced concrete structure while maintaining an existing finishing material.SOLUTION: The protection method of the reinforced concrete structure comprising a reinforced concrete part in which a reinforcing bar is disposed inside concrete and a finishing part provided in the reinforced concrete part, includes: an injection hole forming process of providing an injection hole which penetrates the finishing part and reaches the reinforced concrete part; and a protective layer forming process of forming a protective layer on the reinforced concrete part by injecting an anti-water-absorbing agent into the injection hole.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for protecting a reinforced concrete structure. [Background technology]

[0002] In a reinforced concrete structure in which reinforcing bars are arranged inside concrete, the strength of the entire reinforced concrete structure may decrease due to deterioration of the reinforcing bars. Such deterioration of the reinforcing bars is caused by the penetration of deterioration factors such as moisture into the reinforced concrete structure, which react with the reinforcing bars, resulting in corrosion of the reinforcing bars. Therefore, a water absorption inhibitor is applied to the reinforced concrete structure to form a protective layer and suppress corrosion of the reinforcing bars. For example, Patent Document 1 discloses a method of suppressing corrosion of the reinforcing bars by applying an internal penetration type water absorption inhibitor (corrosion inhibitor) to the surface of the reinforced concrete structure to form a protective layer and suppress corrosion of the reinforcing bars inside the reinforced concrete structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-144313 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 describes that after a protective layer is formed on a reinforced concrete structure, surface finishing such as painting can be performed. However, when forming a protective layer on a reinforced concrete structure on which a finishing material has already been applied, such existing finishing material must be completely removed. Then, after forming the protective layer, the finishing material must be applied again, which increases costs and construction time. In addition, applying a water absorption inhibitor to the surface of an existing finishing material can change the appearance of the existing finishing material, such as its color and surface shape.

[0005] The present invention aims to provide a method for protecting reinforced concrete structures, which can form a protective layer on a reinforced concrete structure while maintaining the existing finishing material, or can form a protective layer on the outdoor side of an exterior wall when construction cannot be performed from the back side of the reinforced concrete structure, for example, in the case of a reinforced concrete structure where it is difficult to install external scaffolding. [Means for solving the problem]

[0006] Some embodiments of the present invention are a method for protecting a reinforced concrete structure comprising a reinforced concrete wall section in which reinforcing bars are arranged inside concrete and an existing finishing material provided on the reinforced concrete wall section, the method comprising the steps of: providing an injection hole through the existing finishing material to reach the reinforced concrete wall section while maintaining the existing finishing material; and injecting a water absorption inhibitor into the injection hole with a pressurized injector to form a protective layer on the reinforced concrete wall section. The water absorption inhibitor is a silane-based impregnating material. The present invention relates to a method for protecting a reinforced concrete structure.

[0007] Other features of the present invention will become apparent from the following specification and drawings. Effect of the Invention

[0008] According to some embodiments of the present invention, a protective layer can be formed on a reinforced concrete structure while preserving the existing finish material. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a method for protecting a reinforced concrete structure 1 according to a first embodiment. [Diagram 2] Fig. 2A is a front view of the reinforced concrete structure 1 of the first embodiment. Fig. 2B is a cross-sectional view of the periphery of an injection hole 30 in the reinforced concrete structure 1 of the first embodiment. [Diagram 3]Fig. 3A is a diagram showing an example of a non-pressurized injector 90. Fig. 3B is a diagram showing an example of a non-pressurized injector 90 (air vent type). Fig. 3C is a diagram showing an example of a pressurized injector 90. [Figure 4] FIG. 4 is a diagram showing the permeation of the water absorption prevention agent 60 in the surface direction of the reinforced concrete structure 1 when the water absorption prevention agent 60 is injected to a depth of 50 mm. [Diagram 5] FIG. 5 is a diagram showing the permeation of the water-absorption prevention agent 60 in the surface direction of the reinforced concrete structure 1 when the water-absorption prevention agent 60 is injected to a depth of 100 mm. [Figure 6] FIG. 6 is a diagram showing the penetration of the water-absorption prevention agent 60 in the depth direction of the reinforced concrete structure 1 when the water-absorption prevention agent 60 is applied to the surface of the concrete 12 separately from the injection of the water-absorption prevention agent 60. [Figure 7] FIG. 7 is a diagram showing a method for protecting a reinforced concrete structure 1 according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] At least the following points will become apparent from the following specification and drawings.

[0011] A method for protecting a reinforced concrete structure comprising a reinforced concrete section in which reinforcing bars are arranged inside the concrete and a finishing section provided on the reinforced concrete section, the method comprising an injection hole forming step of providing an injection hole penetrating the finishing section and reaching the reinforced concrete section, and a protective layer forming step of injecting a water absorption inhibitor into the injection hole to form a protective layer on the reinforced concrete section, is disclosed. According to this method for protecting a reinforced concrete structure, a protective layer can be formed on the reinforced concrete structure while maintaining the existing finishing material. In the present invention, the protective layer means a layer in which a water absorption inhibitor permeates into the concrete and has the effect of suppressing moisture movement.

[0012] The protective layer preferably has a rebar coating layer formed on the surface of the rebar by the penetration of the water absorption inhibitor into the concrete surrounding the rebar. This makes it possible to inhibit the progress of corrosion of the rebar due to deterioration factors such as moisture. In the present invention, the rebar coating layer means a layer that constitutes a part of the protective layer on the rebar in place of a passive film and has the effect of inhibiting corrosion of the rebar.

[0013] The protective layer preferably has a high-concentration water-absorption prevention layer formed in the concrete by the penetration of the water-absorption prevention agent into the concrete. This makes it possible to prevent deterioration factors such as moisture from penetrating into the position of the reinforcing bars inside the concrete. In the present invention, the high-concentration water-absorption prevention layer means a layer that constitutes a part of the protective layer, has a high concentration of water-absorption prevention agent, does not turn wet, and has a strong hydrophobic effect.

[0014] The water absorption inhibitor is preferably a silane-based impregnating material, which allows the water absorption inhibitor to permeate into the concrete, forming a protective layer having a rebar coating layer formed on the surface of the rebar and a high-concentration water absorption prevention layer formed on the concrete.

[0015] The viscosity of the water absorption prevention agent is preferably 0.8 mPa·s to 800 mPa·s. This allows the water absorption prevention agent to permeate into the concrete, forming a protective layer having a rebar coating layer formed on the surface of the rebar and a high-concentration water absorption prevention layer formed on the concrete. In the present invention, the viscosity refers to a value measured by a B-type rotational viscometer at 20°C.

[0016] It is desirable for the viscosity of the water absorption inhibitor to be 10 mPa·s or less, which allows the water absorption inhibitor to penetrate into a wider range of concrete.

[0017] It is preferable that the water absorption inhibitor is injected into the injection hole without applying pressure, which allows the water absorption inhibitor to be injected into the injection hole in a simple manner.

[0018] It is desirable that the injection hole is provided so as to face diagonally downward from the horizontal direction from the surface side of the reinforced concrete structure toward the inside, so that the water absorption prevention agent can be injected without being stuck in the middle of the injection hole even when the water absorption prevention agent is injected without pressure.

[0019] It is preferable that the reinforced concrete structure is provided with a plurality of the injection holes, and the interval between the plurality of injection holes in the surface direction of the reinforced concrete structure is equal to or smaller than the penetration range of the water absorption inhibitor in the surface direction of the reinforced concrete structure, thereby making it possible to cover the reinforced concrete part with a protective layer.

[0020] It is desirable that the vertical spacing between the plurality of injection holes be greater than the horizontal spacing between the plurality of injection holes, so that the reinforced concrete section can be covered with a protective layer.

[0021] The compressive strength of the concrete in the reinforced concrete structure is 50N / mm 2 In this case, it is desirable that the vertical spacing between the multiple injection holes is 300 mm or less and the horizontal spacing between the multiple injection holes is 200 mm or less. This makes it possible to cover the reinforced concrete part with a protective layer.

[0022] The compressive strength of the concrete in the reinforced concrete structure is 18 to 50 N / mm 2 In this case, it is desirable that the vertical spacing between the multiple injection holes is 300 mm or more and the horizontal spacing between the multiple injection holes is 200 mm or more. This makes it possible to cover the reinforced concrete part with a protective layer.

[0023] When the compressive strength of the concrete of the second reinforced concrete structure is greater than the compressive strength of the concrete of the first reinforced concrete structure, it is desirable that the penetration range of the water absorption inhibitor in the surface direction of the second reinforced concrete structure is smaller than the penetration range of the water absorption inhibitor in the surface direction of the first reinforced concrete structure, thereby making it possible to cover the reinforced concrete parts with a protective layer.

[0024] It is preferable that the injection hole is provided in the reinforced concrete portion so as to avoid the reinforcing bar, so that the water absorption prevention agent penetrates only around the reinforcing bar, forming only a reinforcing bar coating layer on the surface of the reinforcing bar, and preventing the formation of a high-concentration water absorption prevention layer in the concrete.

[0025] The injection depth of the injection hole is preferably equal to or less than the distance from the surface of the reinforced concrete structure to the reinforcing bar, so that a high-concentration water absorption prevention layer can be formed on the surface side of the reinforced concrete structure.

[0026] The injection depth of the injection hole is preferably greater than the distance from the surface of the reinforced concrete structure to the reinforcing bar, so that a high-concentration water absorption prevention layer can be formed on the back side of the reinforced concrete structure.

[0027] The protective layer forming step preferably includes applying the water absorption inhibitor to the surface of the reinforced concrete section, which can further inhibit deterioration factors such as moisture from penetrating into the position of the reinforcing bars inside the concrete.

[0028] ===First embodiment=== <Outline of protection methods for reinforced concrete structures> FIG. 1 is a schematic cross-sectional view showing a method for protecting a reinforced concrete structure 1 according to a first embodiment.

[0029] In the following description, each direction is defined as shown in the figure. That is, as shown in Figure 1, the direction perpendicular to the surface of the finishing portion 20 of the reinforced concrete structure 1 is defined as the "depth direction", the side of the surface of the finishing portion 20 relative to the reinforced concrete portion 10 is defined as the "front surface", and the opposite side is defined as the "rear surface" or "back surface". Also, as shown in Figure 1 and Figure 2A described later, the direction horizontal to the surface of the finishing portion 20 of the reinforced concrete structure 1 is defined as the "surface direction". The surface direction includes the "vertical direction" and the "horizontal direction".

[0030] Reinforced concrete structure 1 The reinforced concrete structure 1 of this embodiment is, for example, an architectural structure constructed from reinforced concrete (RC), steel-reinforced concrete (SRC), etc. However, the reinforced concrete structure 1 of this embodiment may be other structures. The reinforced concrete structure 1 has a reinforced concrete part 10 in which reinforcing bars 11 are arranged inside concrete 12, and a finishing part 20 provided on the reinforced concrete part 10.

[0031] The reinforcing bars 11 of the reinforced concrete section 10 are disposed inside the concrete 12 to reinforce the tensile strength of the concrete 12. The reinforcing bars 11 are disposed at positions that ensure a predetermined cover thickness from the front and back surfaces of the concrete 12. The concrete 12 of the reinforced concrete section 10 is formed by pouring concrete into a formwork. Ordinary Portland cement can be used as the cement for the concrete 12 in this embodiment. However, other types of cement may be used as the cement for the concrete 12 in this embodiment. In the following description, the reinforced concrete section 10 may be referred to as the "concrete structure 10."

[0032] The finishing portion 20 is a finishing material applied to the front or back surface of the reinforced concrete portion 10. The finishing portion 20 of this embodiment can use finishing materials such as mortar, plaster, tiles, etc. However, the finishing portion 20 of this embodiment may use other finishing materials.

[0033] - Overview of protection methods for reinforced concrete structures1 The method for protecting a reinforced concrete structure 1 of this embodiment includes an injection hole forming step and a protective layer forming step.

[0034] The injection hole forming process is a process of providing an injection hole 30 that penetrates the finishing portion 20 and reaches the reinforced concrete portion 10. As shown in Fig. 1, an injection hole 30 is provided in a reinforced concrete structure 1, and an injection pipe 91 of an injector 90 is inserted into the injection hole 30. The injector 90 is filled with a water-absorption inhibitor 60, which will be described later, and the water-absorption inhibitor 60 is injected into the injection hole 30 of the reinforced concrete structure 1 through the injection pipe 91.

[0035] The injection holes 30 are provided in the reinforced concrete structure 1, and are holes into which a water absorption prevention agent 60, described later, is injected. In this embodiment, the injection holes 30 are provided by drilling. However, the injection holes 30 of this embodiment may be provided by other methods. As shown in FIG. 1, the reinforced concrete structure 1 of this embodiment is provided with a plurality of injection holes 30 (here, five) in the vertical direction, and an injection pipe 91 of a syringe 90 is inserted into each of the injection holes 30. The arrangement direction and number of the injection holes 30 of this embodiment will be described later.

[0036] The size (inner diameter) of injection hole 30 is about 10 mm in diameter. However, the size (inner diameter) of injection hole 30 is not limited to this. In other words, the size (inner diameter) of injection hole 30 only needs to be larger than the thickness (outer diameter) of injection tube 91 of injector 90, and large enough not to impair the appearance of finishing portion 20. It should be as small as possible. Note that "to the extent that it does not impair the appearance of the finishing part 20" means, for example, that when tiles are used as the finishing part 20, the size (inner diameter) of the injection hole 30 is set to be equal to or smaller than the size of the joints of the tiles, so that the effect on the appearance is small.

[0037] As shown in FIG. 1, the injection hole 30 penetrates the finishing portion 20 and reaches the reinforced concrete portion 10. In other words, the injection depth of the injection hole 30 (D1 shown in FIG. 1) is equal to or greater than the thickness of the finishing portion 20 (D2 shown in FIG. 1) (D1≧D2). The "injection depth of the injection hole 30" refers to the distance in the depth direction from the inlet on the surface side of the injection hole 30 to the end (D1 shown in FIG. 1). As shown in FIG. 1, the injection depth of the injection hole 30 is equal to or less than the distance from the surface of the reinforced concrete structure 1 to the reinforcing bar 11 (D3 shown in FIG. 1) (D1≦D3). This allows the protective layer 80 formed on the concrete 12 to be formed on the surface side of the reinforced concrete structure 1. When the protective layer 80 is formed on the surface side of the reinforced concrete structure 1, it is possible to suppress the intrusion of deterioration factors such as moisture from the surface side of the reinforced concrete structure 1. The protective layer 80 will be described later.

[0038] Furthermore, as shown in FIG. 1, the injection hole 30 of this embodiment is provided so as to face diagonally downward from the surface side of the reinforced concrete structure 1 toward the inside (back side) of the structure. That is, the tip of the injection hole 30 is provided so as to face diagonally downward from the horizontal direction. Therefore, the water-absorption prevention agent 60 injected into the injection hole 30 accumulates inside the injection hole 30 from the tip of the injection hole 30 due to gravity. This allows the water-absorption prevention agent to be injected without remaining in the middle of the injection hole even when the water-absorption prevention agent is injected without pressure. The injection hole 30 of this embodiment may be provided so as to face the horizontal direction or may be provided so as to face another direction. In addition, the entrance of the injection hole 30 is sealed in order to prevent the water-absorption prevention agent 60 from spilling out of the entrance of the injection hole 30. However, if the viscosity of the water-absorption prevention agent 60 is high and there is little risk of the water-absorption prevention agent 60 spilling out of the entrance on the surface side of the injection hole 30, the entrance may not be sealed.

[0039] The protective layer forming process is a process of forming a protective layer 80 on the reinforced concrete part 10. As shown in Fig. 1, the water absorption prevention agent 60 injected into the injection hole 30 permeates into the concrete 12 of the reinforced concrete part 10, so that the protective layer 80 is formed on the reinforced concrete part 10.

[0040] The protective layer 80 is a layer that has hydrophobic properties in the reinforced concrete part 10. In the reinforced concrete part 10 of this embodiment, the protective layer 80 prevents the reinforcing bars 11 from coming into contact with moisture and chloride ions that have penetrated into the concrete 12, thereby suppressing the progression of corrosion of the reinforcing bars 11. This makes it possible to suppress deterioration of the reinforcing bars 11. Note that the range of the protective layer 80 shown in FIG. 1 (the range surrounded by the dashed line) is illustrated diagrammatically for the purpose of explanation, and is not limited thereto.

[0041] ·Small summary As described above, the method for protecting a reinforced concrete structure 1 in this embodiment is a method for protecting a reinforced concrete structure 1 comprising a reinforced concrete part 10 in which reinforcing bars 11 are disposed inside concrete 12, and a finishing part 20 provided on the reinforced concrete part 10. The method for protecting a reinforced concrete structure 1 in this embodiment includes an injection hole forming step of providing an injection hole 30 that penetrates the finishing part 20 and reaches the reinforced concrete part 10, and a protective layer forming step of injecting a water absorption inhibitor 60 into the injection hole 30 and forming a protective layer 80 on the reinforced concrete part 10.

[0042] According to the method for protecting the reinforced concrete structure 1 of the present embodiment, the water absorption inhibitor 60 is not applied to the surface of the finishing portion 20 of the reinforced concrete structure 1, but is applied to the surface of the finishing portion 20 by penetrating the finishing portion 20. The water absorption inhibitor 60 is injected into the injection hole 30 that reaches the reinforced concrete section 10, and a protective layer 80 is formed inside the reinforced concrete section 10. This eliminates the need to apply an additional finishing material on the finishing section 20, or to completely remove the finishing section 20 once and then apply a finishing material again after forming the protective layer 80 on the surface of the reinforced concrete section 10. This makes it possible to form the protective layer 80 on the reinforced concrete structure 1 while maintaining the existing finishing material (finishing section 20).

[0043] In addition to forming a protective layer 80 inside the reinforced concrete section 10 by injecting a water-absorption prevention agent 60 into the injection hole 30 that penetrates the finishing section 20 and reaches the reinforced concrete section 10, a protective layer 80 may be formed on the surface side of the reinforced concrete section 10 by applying the water-absorption prevention agent 60 to the surface of the reinforced concrete section 10 of the reinforced concrete structure 1.

[0044] <Protective layer for reinforced concrete> FIG. 2A is a front view of the reinforced concrete structure 1 of the first embodiment. In FIG. 2A, the position of the reinforcing bar 11 arranged inside the concrete 11 in the reinforced concrete structure 1 of this embodiment is indicated by a broken line. As shown in FIG. 2A, in the reinforced concrete structure 1 of this embodiment, the injection holes 30 are arranged in a horizontal and vertical array. In addition, a protective layer 80 is formed around the injection holes 30 as indicated by an elliptical broken line. Note that FIG. 2A illustrates only a part of the protective layer 80. In the following description, the vertical interval (pitch) of the multiple injection holes 30 may be referred to as PV, and the horizontal interval (pitch) of the multiple injection holes 30 may be referred to as PH. In addition, the vertical size of the protective layer 80 formed by the water absorption prevention agent 60 injected into each injection hole 30 may be referred to as DV, and the horizontal size may be referred to as DH.

[0045] The intervals (PV and PH) between the plurality of injection holes 30 in the surface direction (vertical direction and horizontal direction) of the reinforced concrete structure 1 of the present embodiment are equal to or less than the sizes (DV and DH) of the protective layer 80 of the water absorption inhibitor 60 in the surface direction (vertical direction and horizontal direction) of the reinforced concrete structure 1 (PV <DV and PH <DH). Thereby, the reinforced concrete portion 10 can be covered with the protective layer 80. The sizes (DV and DH) of the protective layer 80 of the water absorption inhibitor 60 are such that the size (DV) of the protective layer 80 of the water absorption inhibitor 60 in the vertical direction is larger than the size (DH) of the protective layer 80 of the water absorption inhibitor 60 in the horizontal direction due to the influence of gravity (DV> DH). For this reason, the vertical interval (PV) between the plurality of injection holes 30 can be made larger than the horizontal interval (PH) between the plurality of injection holes 30 (PV> PH).

[0046] FIG. 2B is a cross-sectional view around the injection hole 30 in the reinforced concrete structure 1 of the first embodiment. In FIG. 2B, among the plurality of injection holes 30 described above, the state of the protective layer 80 formed around a certain injection hole 30 is schematically shown. In FIG. 2B, for ease of explanation, an example is shown in which the injection hole 30 is provided so as to face the horizontal direction from the surface side to the inside (back side) of the reinforced concrete structure 1. Further, in FIG. 2B, the illustration of the injector 90 is omitted for ease of explanation. As shown in FIG. 2B, the water absorption inhibitor 60 is injected into the injection hole 30.

[0047] The water absorption inhibitor 60 is a concrete protective material that forms a layer (protective layer 80) having a hydrophobic property in the reinforced concrete portion. The water absorption inhibitor 60 has the property of penetrating into concrete. In the protection method of the reinforced concrete structure 1 of the present embodiment, the water absorption inhibitor 60 injected into the injection hole 30 penetrates from the inner wall of the injection hole 30 into the inside of the concrete 12, and a protective layer 80 is formed around the injection hole 30 of the reinforced concrete portion 10. Since the water absorption inhibitor 60 penetrates from the inner wall of the injection hole 30 to the outside (inside of the concrete 12), the concentration of the water absorption inhibitor 60 gradually decreases toward the outside of the injection hole 30 within the protective layer 80 going down.

[0048] The water absorption prevention agent 60 of this embodiment uses a silane-based impregnating material. The silane-based impregnating material is a type of impregnating material having a hydrophobic group (alkyl group) of silicone having a water repellent function. However, the water absorption prevention agent 60 of this embodiment may be an impregnating material other than the silane-based impregnating material.

[0049] 2B is the range (penetration range) into which the water-absorption prevention agent 60 permeates. The water-absorption prevention agent 60 permeates into the concrete 12 from the inner wall of the injection hole 30 toward the outside of the injection hole 30, and forms the protective layer 80. In this embodiment, the water-absorption prevention agent 60 permeates into the concrete 12, and within the range of the protective layer 80, a high-concentration water-absorption prevention layer 71 and a rebar coating layer 72 are formed.

[0050] The high-concentration water-absorption prevention layer 71 is a layer that suppresses the infiltration of water into the concrete 12. The high-concentration water-absorption prevention layer 71 is formed on the outside of the injection hole 30, and is a portion in which the concentration of the water-absorption prevention agent 60 that has permeated into the concrete 12 is high. In this embodiment, the high-concentration water-absorption prevention layer 71 is a layer that does not become wet even when water is sprayed, and has a particularly high concentration of the water-absorption prevention agent 60. The high-concentration water-absorption prevention layer 71 can suppress the infiltration of deterioration factors such as moisture into the position of the reinforcing bar 11 inside the concrete 12. In addition, a reinforcing bar coating layer 72 is formed around the reinforcing bar 11 within the range of the protective layer 80. The reinforcing bar coating layer 72 is a layer that suppresses the adhesion of water to the reinforcing bar 11. The reinforcing bar coating layer 72 is formed when the water-absorption prevention agent 60 that has permeated into the concrete 12 reaches the reinforcing bar 11 and coats the periphery of the reinforcing bar 11 along the surface of the reinforcing bar 11.

[0051] As shown in Fig. 2A and Fig. 2B, the injection hole 30 is provided in the reinforced concrete part 10 so as to avoid the reinforcing bar 11. If the injection hole 30 is provided so as to contact the reinforcing bar 11, that is, if the reinforcing bar 11 is exposed on the inner wall of the injection hole 30, the water absorption inhibitor 60 will directly flow around the reinforcing bar 11 and will be difficult to penetrate into the concrete 12. Therefore, by providing the injection hole 30 in the reinforced concrete part 10 so as to avoid the reinforcing bar 11, it is possible to prevent the water absorption inhibitor 60 from penetrating only around the reinforcing bar 11, which would result in the formation of only the reinforcing bar coating layer 72 on the surface of the reinforcing bar 11. Also, by providing the injection hole 30 in the reinforced concrete part 10 so as to avoid the reinforcing bar 11, it is possible to form a protective layer 80 of a desired range for suppressing the infiltration of water into the concrete 12.

[0052] <Injector> FIG. 3A is a diagram showing an example of a non-pressurized injector 90. FIG. 3B is a diagram showing an example of a non-pressurized injector 90 (air vent type). The injector 90 shown in FIGS. 3A and 3B has a container 92 for filling the water-absorption prevention agent 60 and an injection pipe 91 for injecting the water-absorption prevention agent 60 into the injection hole 30. The injection pipe 91 is inserted into the injection hole 30, so that the water-absorption prevention agent 60 is injected into the injection hole 30 through the injection pipe 91. Note that the lower the viscosity of the water-absorption prevention agent 60, the easier it is for the water-absorption prevention agent 60 to penetrate into the concrete 12. That is, the lower the viscosity of the water-absorption prevention agent 60, the larger the protective layer 80 of the water-absorption prevention agent 60. Therefore, for example, when the viscosity of the water-absorption prevention agent 60 is 10 mPa·s or less, it is advantageous to inject the water-absorption prevention agent 60 into the injection hole 30 without pressure. This allows the water-absorption prevention agent to be injected into the injection hole 30 in a simple manner.

[0053] 3B further includes an air vent pipe 93. The air vent pipe 93 is a pipe for sending out air bubbles generated when the water absorption prevention agent 60 is injected through the injection hole 30 and permeates into the concrete 12. The air vent pipe 93 is injected into the injection hole 30 together with the injection pipe 91, and air bubbles generated when the water absorption prevention agent 60 permeates into the concrete 12 are sent out through the air vent pipe 93.

[0054] 3C is a diagram showing an example of a pressurized injector 90. In the injector 90 shown in FIG. 3C, a pressing surface 95 in a container 92 is pressed toward the injection hole 30 by the compressive force of a pressurized rubber 94, so that the water-absorption inhibitor 60 in the container 92 is pressurized and injected into the injection hole 30. In this embodiment, the water-absorption inhibitor 60 is pressurized to about 0.05 to 0.2 MPa and injected into the injection hole 30. When the viscosity of the water-absorption inhibitor 60 is high, it is advantageous to pressurize the water-absorption inhibitor 60 and inject it into the injection hole 30. This makes it easier for the water-absorption inhibitor 60 to permeate into the concrete 12 even if the viscosity of the water-absorption inhibitor 60 is high.

[0055] <Example> Injection test overview In the method for protecting a reinforced concrete structure 1 according to the present embodiment, an injection test of the water absorption inhibitor 60 into the reinforced concrete portion 10 was carried out. In the injection test, a wall-shaped specimen in which reinforcing bars were arranged inside the concrete was first produced. This wall-shaped specimen was provided with a plurality of injection holes, and the water absorption inhibitor was injected into the injection holes, after which a plurality of samples for component analysis were taken. In addition to the injection into the injection holes, the water absorption inhibitor was applied to the concrete surface, and 28 days later, a plurality of samples for component analysis in the depth direction were taken. The samples for component analysis were taken in two ways: by drilling holes and by using concrete cores.

[0056] Sampling by drilling holes was performed with a 10.5 mm drill bit. Samples were collected at multiple locations at 50 mm intervals in both the vertical and horizontal directions from the injection hole position. In this test, samples were collected at a total of eight locations in the vertical and horizontal directions. Furthermore, samples were collected at each location from a depth of 40 mm to 50 mm from the concrete surface when the injection hole 30 was 50 mm deep, and from a depth of 90 mm to 100 mm from the concrete surface when the injection hole 30 was 100 mm deep, and component analysis was performed using pyrolysis gas chromatography.

[0057] Concrete cores were taken as 80mm or 100mm diameter concrete cores including the injection hole. Water was also sprayed on the fractured surface of the collected samples to confirm that the area did not turn wet, and this area was designated as the high-concentration water absorption prevention layer. Furthermore, in places where a water absorption prevention agent was applied to the concrete surface, 80mm diameter concrete cores were taken, and five discs were cut out at 20mm intervals to a depth of 100mm from the applied surface of the concrete core, each of which was crushed and then analyzed for components by pyrolysis gas chromatography.

[0058] <Measurement conditions for pyrolysis gas chromatography> The component analysis by pyrolysis gas chromatography was performed under the measurement conditions shown in Table 1 below.

[0059] [Table 1]

[0060] In this test, the compressive strength of the concrete and the injection depth of the injection hole were changed, and water absorption prevention agent A, a silane-based impregnating material with a viscosity of 1.2 mPa s, was injected into the injection hole without pressure, as shown in Table 2 below. The viscosity of the water absorption prevention agent was measured using a B-type rotational viscometer at 20°C.

[0061] [Table 2]

[0062] - Permeation distance of water absorption inhibitor 60 in the surface direction Fig. 4 is a diagram showing the permeation of the water absorption prevention agent 60 in the surface direction of the reinforced concrete structure 1 when the injection depth of the water absorption prevention agent 60 is 50 mm. Fig. 5 is a diagram showing the permeation of the water absorption prevention agent 60 in the surface direction of the reinforced concrete structure 1 when the injection depth of the water absorption prevention agent 60 is 100 mm.

[0063] As shown in Figures 4 and 5, the compressive strength of the concrete was 18N / mm at each point from the center of the injection hole. 2 The reinforced concrete structure 1 (Example 3) has a concrete compressive strength of 50 N / mm 2 The content of the water absorption inhibitor 60 is higher than that of the example of reinforced concrete structure 1 (Example 1) in Example 1. This indicates that the smaller the compressive strength of the concrete, the easier it is for the water absorption inhibitor 60 to penetrate into the concrete. As described above, the water absorption inhibitor 60 penetrates from the inner wall of the injection hole 30 to the outside (inside the concrete 12), so that within the protective layer 80, the concentration of the water absorption inhibitor 60 gradually decreases toward the outside of the injection hole 30. Taking the above into consideration, the smaller the compressive strength of the concrete, the wider the protective layer 80 of the water absorption inhibitor 60 will be. Therefore, when the compressive strength of the concrete is 18 N / mm 2 The protective layer 80 of the water absorption inhibitor 60 in the surface direction of the reinforced concrete structure 1 (Example 3) is 2 4. The thickness of the protective layer 80 of the water absorption inhibitor 60 in the surface direction of the reinforced concrete structure 1 (Example 1) is larger than that of the protective layer 80 of the water absorption inhibitor 60 in the surface direction of the reinforced concrete structure 1 (Example 1).

[0064] -Depth penetration distance of water absorption inhibitor 60 FIG. 6 is a diagram showing the penetration of the water-absorption prevention agent 60 in the depth direction of the reinforced concrete structure 1 when the water-absorption prevention agent 60 is applied to the surface of the concrete 12 separately from the injection of the water-absorption prevention agent 60.

[0065] As shown in Fig. 6, in the case of a reinforced concrete structure 1 having a concrete compressive strength of 18 N / mm2, the concentration of the water absorption prevention agent 60 drops suddenly in the range of 30 mm to 50 mm from the surface. In addition, in the case of a reinforced concrete structure 1 having a concrete compressive strength of 50 N / mm2, the concentration of the water absorption prevention agent 60 drops suddenly in the range of 10 mm to 30 mm from the surface. The above ranges are the boundaries of the high concentration water absorption prevention layer 71.

[0066] Viscosity of water absorption inhibitor 60 Table 3 below shows the results of checking the range where water does not turn wet when water is sprayed on the fractured surface when samples are collected using concrete cores, and the results of checking the range where the components of Water Absorption Prevention Agent 60 penetrate when samples are collected by drilling holes. The range where water does not turn wet when water is sprayed on the fractured surface was checked for Water Absorption Prevention Agent A, which has a viscosity of 1.2 mPa s, and Water Absorption Prevention Agent B, a silane-based impregnating material with a viscosity of 762 mPa s. [Table 3]

[0067] ·Small summary Table 4 below shows the scope of application of the protection method for reinforced concrete structure 1 using water absorption prevention agent A (1.2 mPa·s) and water absorption prevention agent B (762 mPa·s).

[0068] [Table 4]

[0069] The viscosity of the water-absorption prevention agent 60 may be any viscosity between 0.8 mPa·s and 800 mPa·s. It is particularly advantageous for the viscosity of the water-absorption prevention agent 60 to be 10 mPa·s or less. This makes it possible to widen the range in which the water-absorption prevention agent 60 permeates into the concrete 12. As described above, when the viscosity of the water-absorption prevention agent 60 is 10 mPa·s or less, the water-absorption prevention agent 60 can be injected into the injection hole 30 without applying pressure.

[0070] The compressive strength of concrete is 18 to 50 N / mm 2 However, the compressive strength of the reinforced concrete structure 1 may be any value between 50 N / mm2 and 18 N / mm2. 2 The penetration range of the water absorption inhibitor 60 gradually increases along the length of the reinforced concrete structure 1 .

[0071] The compressive strength of concrete is 50N / mm 2 When the concrete has a compressive strength of 18 to 50 N / mm, it is preferable that the vertical spacing (PV) of the multiple injection holes 30 is 300 mm or less (100 mm upward + 200 mm downward) and the horizontal spacing (PH) of the multiple injection holes is 200 mm or less (100 mm leftward + 100 mm rightward). 2 When the water absorption inhibitor B is used, the injection interval of the injection holes 30 is calculated based on the ratio of the water absorption inhibitor A to the water absorption inhibitor B within a range where the water absorption inhibitor A and the water absorption inhibitor B do not turn a wet color.

[0072] ===Second embodiment=== FIG. 7 is a diagram showing a method for protecting a reinforced concrete structure 1 according to the second embodiment.

[0073] In the first embodiment described above, as shown in Fig. 1, the injection depth of injection hole 30 was equal to or less than the distance from the surface of reinforced concrete structure 1 to reinforcing bar 11. However, in this embodiment, as shown in Fig. 7, the injection depth of injection hole 30 is greater than the distance from the surface of reinforced concrete structure 1 to reinforcing bar 11. This makes it possible to form protective layer 80 on concrete 12 on the back side of reinforced concrete structure 1. When protective layer 80 is formed on the back side of reinforced concrete structure 1, it is possible to inhibit the intrusion of deterioration factors such as moisture from the back side of reinforced concrete structure 1.

[0074] ===Other=== The above-described embodiment is for the purpose of facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof. [Explanation of symbols]

[0075] 1 Reinforced concrete structure, 10 Reinforced concrete section, 11 Reinforcement bar, 12 Concrete, 20 Finishing part, 30 Injection hole, 60 Water absorption prevention agent, 71 High concentration water absorption prevention layer, 72 Reinforced concrete coating layer, 80 protective layer, 90 injector, 91 injection tube, 92 container, 93 air vent tube, 94 Pressure rubber, 95 Pressing surface

Claims

1. A method for protecting a reinforced concrete structure comprising a reinforced concrete wall portion in which a reinforcing bar is disposed inside concrete and an existing finishing material provided on the reinforced concrete wall portion, comprising: an injection hole forming process for forming an injection hole through the existing finishing material to reach the reinforced concrete wall portion while maintaining the existing finishing material; and a protective layer forming step of injecting a water absorption inhibitor into the injection hole by a pressure injector to form a protective layer on the reinforced concrete wall. The water absorption inhibitor is a silane-based impregnating material. A method for protecting a reinforced concrete structure.

2. A method for protecting a reinforced concrete structure as described in claim 1, comprising: The viscosity of the water absorption inhibitor is 0.8 mPa·s to 800 mPa·s. A method for protecting a reinforced concrete structure.

3. A method for protecting a reinforced concrete structure as described in claim 2, comprising: The viscosity of the water absorption inhibitor is 0.8 mPa·s to 10 mPa·s. A method for protecting a reinforced concrete structure.

4. A method for protecting a reinforced concrete structure as described in claim 2, comprising: The reinforced concrete structure is provided with a plurality of the injection holes, The interval between the plurality of injection holes in the surface direction of the reinforced concrete structure is equal to or less than the size of the penetration range of the water absorption inhibitor in the surface direction of the reinforced concrete structure. A method for protecting a reinforced concrete structure.

5. A method for protecting a reinforced concrete structure as described in claim 4, comprising: The vertical spacing between the plurality of injection holes is greater than the horizontal spacing between the plurality of injection holes. A method for protecting a reinforced concrete structure.

6. A method for protecting a reinforced concrete structure comprising a reinforced concrete wall portion in which a reinforcing bar is disposed inside concrete and an existing finishing material provided on the reinforced concrete wall portion, comprising: an injection hole forming process for forming an injection hole through the existing finishing material to reach the reinforced concrete wall portion while maintaining the existing finishing material; and a protective layer forming step of injecting a water absorption inhibitor into the injection hole by a pressure injector to form a protective layer on the reinforced concrete wall. The viscosity of the water absorption inhibitor is 0.8 mPa·s to 800 mPa·s, The reinforced concrete structure is provided with a plurality of the injection holes, a distance between the plurality of injection holes in a surface direction of the reinforced concrete structure is equal to or less than a size of a penetration range of the water absorption inhibitor in a surface direction of the reinforced concrete structure; the vertical spacing between the plurality of injection holes is greater than the horizontal spacing between the plurality of injection holes; When the compressive strength of the concrete of the reinforced concrete structure is 50 N / mm2, the vertical spacing between the multiple injection holes is 300 mm or less, and the horizontal spacing between the multiple injection holes is 200 mm or less. A method for protecting a reinforced concrete structure.

7. A method for protecting a reinforced concrete structure comprising a reinforced concrete wall portion in which a reinforcing bar is disposed inside concrete and an existing finishing material provided on the reinforced concrete wall portion, comprising: an injection hole forming process for forming an injection hole through the existing finishing material to reach the reinforced concrete wall portion while maintaining the existing finishing material; and a protective layer forming step of injecting a water absorption inhibitor into the injection hole by a pressure injector to form a protective layer on the reinforced concrete wall. The viscosity of the water absorption inhibitor is 0.8 mPa·s to 800 mPa·s, The reinforced concrete structure is provided with a plurality of the injection holes, a distance between the plurality of injection holes in a surface direction of the reinforced concrete structure is equal to or less than a size of a penetration range of the water absorption inhibitor in a surface direction of the reinforced concrete structure; the vertical spacing between the plurality of injection holes is greater than the horizontal spacing between the plurality of injection holes; When the compressive strength of the concrete of the reinforced concrete structure is 18 to 50 N / mm2, the vertical spacing between the multiple injection holes is 300 mm or more, and the horizontal spacing between the multiple injection holes is 200 mm or more. A method for protecting a reinforced concrete structure.

8. A method for protecting a reinforced concrete structure according to any one of claims 2 to 7, comprising: than the compressive strength of the concrete of the first reinforced concrete structure, When the compressive strength of the concrete of the second reinforced concrete structure is large, The penetration range of the water absorption inhibitor in the surface direction of the second reinforced concrete structure is smaller than the penetration range of the water absorption inhibitor in the surface direction of the first reinforced concrete structure. A method for protecting a reinforced concrete structure.

9. A method for protecting a reinforced concrete structure according to any one of claims 1 to 8, comprising: The protective layer has a reinforcing bar coating layer formed on the surface of the reinforcing bar by the water absorption inhibitor penetrating into the concrete around the reinforcing bar. A method for protecting a reinforced concrete structure.

10. A method for protecting a reinforced concrete structure according to any one of claims 1 to 9, comprising: The protective layer has a high-concentration water absorption prevention layer formed on the concrete by the water absorption prevention agent permeating into the concrete. A method for protecting a reinforced concrete structure.

11. A method for protecting a reinforced concrete structure according to any one of claims 1 to 10, comprising: The injection hole is provided in the reinforced concrete wall portion so as to avoid the reinforcing bars. A method for protecting a reinforced concrete structure.

12. A method for protecting a reinforced concrete structure according to any one of claims 1 to 11, comprising: The injection depth of the injection hole is equal to or less than the distance from the surface of the reinforced concrete structure to the reinforcing bar. A method for protecting a reinforced concrete structure.

13. A method for protecting a reinforced concrete structure according to any one of claims 1 to 11, comprising: The injection depth of the injection hole is greater than the distance from the surface of the reinforced concrete structure to the reinforcing bar. A method for protecting a reinforced concrete structure.

14. A method for protecting a reinforced concrete structure according to any one of claims 1 to 13, comprising: The method for protecting a reinforced concrete structure, wherein the protective layer forming step includes applying the water absorption inhibitor to a surface of the reinforced concrete wall portion.

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