JP2012112199A - Method for repairing crack of concrete structure, and concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete structure of which cracks generated on the surface of or inside the concrete structure can be repaired without identification of the crack location, and a method for repairing cracks of a concrete structure.SOLUTION: A concrete structure includes a hollow passage provided with an opening through which a repairing material is injected, an inner wall surface exposing a material which constitutes the concrete structure, and a water shut-off region which is formed on the surface of the inner wall by surface treatment and shuts off the repairing material and water. A method for repairing cracks of the concrete structure includes injecting the repair material into the hollow passage from the opening, so that the repair material is pressed into cracks formed in the concrete structure.

Description

  The present invention relates to a concrete structure and a crack repairing method for a concrete structure.

  Concrete is used in most of the structures currently in use, and construction is done with due consideration. However, cracks occur in concrete due to excessive tensile stress exceeding its material strength, temperature stress associated with cement hydration reaction, and tensile stress associated with shrinkage, and it is very difficult to completely prevent it. Cracks are not only a direct deterioration such as a decrease in the strength and airtightness of concrete, but even a slight crack makes it easier for carbon dioxide, acid rain, or salt in the air to enter the enclosure. It promotes deterioration due to sexualization, salt damage, etc., and induces rust of the reinforcing bars, causing early deterioration. The early deterioration of concrete due to cracking reduces the durability and safety of the structure and shortens the useful life of the structure.

  Therefore, it is necessary to periodically inspect the concrete structure and repair the cracks. As the crack inspection, there is a method in which a crack appearing on the surface of the concrete structure is visually confirmed and the crack is repaired directly from the outside of the concrete structure. However, according to such a method, it is impossible to detect and repair cracks generated in the concrete structure. In addition, most crack inspections rely on human hands, and many inspections rely on visual inspection, so the reliability of the inspection is not certain. In addition, wall surfaces of nuclear waste treatment facilities and nuclear power plants may not be inspected or even repaired during the period of use of the facility.

  Patent Document 1 discloses a method for repairing a crack in a concrete structure, characterized in that a repair agent holding body that holds a repair agent therein is mixed with concrete before hardening at the time of construction (see claim 1). .) Is described. According to this invention, when a crack is generated in a concrete structure, the repair agent holder breaks or the shell breaks, so that the repair agent flows out from the inside and is filled into fine cracks by capillary tension. It is repaired "(see paragraph 0005).

  Patent Document 2 describes a method of forming a conduit for detecting and repairing cracks such as cracks and cracks inside a concrete frame.

JP 2000-145158 A JP 2005-68877 A

  It is an object of the present invention to provide a concrete structure capable of repairing a crack generated on the surface and inside of a concrete structure and a method for repairing the crack of the concrete structure without specifying the place where the crack has occurred. And

As means for solving the problems,
(1) An opening into which a repair agent is introduced into a concrete structure, an inner wall surface from which a material forming the concrete structure is exposed, and the repair agent formed on the surface of the inner wall surface by surface treatment; Forming a hollow path with a moisture blocking region that blocks moisture;
A crack repair method for a concrete structure, wherein the repair agent is introduced into a crack formed in the concrete structure by introducing the repair agent into the hollow path from the opening,

A preferred embodiment of (1) is as follows:
(2) After the repair agent has been pressed into the crack, the repair agent is discharged from the hollow path,
(3) The moisture blocking region is formed of at least one surface treatment agent selected from the group consisting of a one-component moisture-curing epoxy resin that cures at room temperature and a surface impregnating material,
(4) The repair agent is a one-component moisture-curable epoxy resin that cures at room temperature,
(5) The repair agent has a first repair agent and a second repair agent having different viscosities, and the first repair agent and the second repair agent are respectively introduced into hollow paths having different paths. This is a method for repairing cracks in concrete structures.

As means for solving the other problems,
(6) Opening into which the repair agent is introduced, an inner wall surface from which the material forming the concrete structure is exposed, and moisture formed by surface treatment on the surface of the inner wall surface to block the repair agent from moisture It is a concrete structure characterized by having a hollow path provided with a blocking region.

A preferred embodiment of (6) is as follows:
(7) The moisture blocking region is formed of at least one surface treatment agent selected from the group consisting of a one-component moisture-curing epoxy resin that cures at room temperature and a surface impregnating material.

  According to the concrete structure and the crack repairing method of the present invention, it is possible to repair the cracks formed on the surface and inside of the concrete structure only by introducing a repair agent into the hollow passage formed in the concrete structure. Because it can, there is no need to inspect cracks. Therefore, it is possible to reduce the labor and cost of crack inspection. In addition, fine cracks that are easily overlooked can be repaired.

  Further, according to the concrete structure and the crack repairing method of the present invention, since the hollow path is arranged in the concrete structure, a repair agent is introduced from the opening of the hollow path in a place away from the crack generation place. Can be press-fitted into a crack. Therefore, cracks can be repaired safely from a remote location even in places where crack inspection and repair are difficult.

  Further, the concrete structure includes an inner wall surface from which a material forming the concrete structure is exposed, and a moisture blocking region formed by surface treatment on the surface of the inner wall surface to block the repair agent and moisture. Since it has an air passage, it does not harden even if the repair agent is held in the hollow passage for a long time. Therefore, if a repair agent is introduced into the hollow path before cracking occurs in the concrete structure, the repair agent in the hollow path is automatically pressed into the crack when cracking occurs. Cracks generated in the self-repair.

  In the crack repairing method for a concrete structure according to the present invention, the repair agent is discharged from the hollow path after the repair agent introduced into the hollow path is pressed into the crack formed in the concrete structure. Multiple repairs are possible without obstruction.

  In the method for repairing a crack in a concrete structure according to the present invention, since a repair agent having a plurality of viscosities is introduced into a plurality of hollow paths, the repair agent can be injected into both a fine crack and a large crack. As a result, it is possible to reliably repair cracks inside and on the surface of the concrete structure.

  As one of the conventional concrete structures, for example, in a structure in which a glass tube is embedded in a concrete structure, a gap is generated between the glass tube and the concrete when the concrete is cured, and the concrete structure and the glass tube are At the same time, cracks did not occur at the same time, and the repair agent in the glass tube was not injected into the cracks. However, the hollow path in the concrete structure of the present invention has a moisture blocking region that is formed by surface treatment on the surface of the inner wall surface and blocks the repair agent and moisture, so stress generated inside the concrete structure When a crack is formed by the above, the stress is directly transmitted to the moisture barrier region, so that a crack is simultaneously generated between the concrete structure and the moisture barrier region. Therefore, since the repair agent filled in the hollow path can be surely press-fitted into the crack, the crack can be reliably repaired.

Fig.1 (a) is sectional explanatory drawing of the concrete structure which is an example of the concrete structure based on this invention. FIG.1 (b) is a side view at the time of seeing the concrete structure in Fig.1 (a) from A direction. FIG. 2 is an explanatory diagram for explaining an example of a method for forming a hollow path. FIG. 3 is an explanatory diagram for explaining an example of a crack repairing method for a concrete structure. FIG. 4 is an explanatory diagram for explaining another example of a crack repairing method for a concrete structure. FIG. 5 is an explanatory diagram for explaining another example of a crack repairing method for a concrete structure, FIG. 5 (a) is a cross-sectional explanatory diagram of the concrete structure, and FIG. 5 (b) is FIG. 5. It is a side view at the time of seeing the concrete structure in (a) from the B direction. FIG. 6 is a flowchart showing the test procedure of the example. FIG. 7 is a flowchart showing the test procedure of another embodiment. FIG. 8 is a flowchart showing a test procedure of still another embodiment.

  Hereinafter, a concrete structure and a crack repairing method thereof according to the present invention will be described with reference to the drawings. Fig.1 (a) is sectional explanatory drawing of the concrete structure which is an example of the concrete structure based on this invention. FIG.1 (b) is a side view at the time of seeing the concrete structure in Fig.1 (a) from A direction.

  The concrete structure 1 of this embodiment includes a first opening 3a into which a repair agent is introduced, a second opening 3b through which the repair agent is discharged, and an inner wall surface 4 from which the material forming the concrete structure 1 is exposed. And a hollow passage 2 provided on the surface of the inner wall surface 4 with a moisture blocking region 5 formed by surface treatment for blocking the repair agent and moisture.

  Examples of the structure in which the hollow path 2 is formed include structures that are assumed to crack in civil engineering structures such as beams, columns, walls, bridges, and dams in RC ramen structures. . In particular, the hollow passage 2 is suitable for beams, columns, walls and the like formed of concrete such as nuclear waste treatment facilities and nuclear power plants under conditions where it is difficult to inspect cracks and repair cracks. Formed.

  The hollow path 2 formed in the concrete structure 1 of this embodiment has a first opening 3a on one outer surface of the concrete structure 1, and is opposite to the opening 3a with the concrete structure 1 interposed therebetween. A second opening 3b is provided on the outer surface on the side. The hollow path only needs to have at least one opening into which the repair agent is introduced, and the number of openings is not particularly limited as long as the repair agent introduced from the opening can be discharged. The repair agent may be introduced from the same, and the repair agent may be discharged from the same opening, or the repair agent may be introduced from one or more openings and the repair agent may be discharged from one or more openings.

  The hollow path 2 of this embodiment has a hollow cylindrical shape, and is arranged in a straight line from the first opening 3a to the second opening 3b by being decentered in one surface direction from the axis of the concrete structure 1. Yes. The place where the hollow path is formed is a place where cracks are expected to occur, as long as it does not cause a problem in the strength required for the concrete structure by forming the hollow path. For example, in a beam of an RC rigid frame structure, it is preferable that the beam is disposed between a lower surface of the beam and a main bar disposed closest to the lower surface.

  As shown in FIG. 1, one straight hollow path 2 may be arranged in the hollow path 2, or a plurality of hollow paths may be arranged in parallel or randomly, or arranged in parallel. A parallel-arranged hollow path may be further arranged so as to be orthogonal to the parallel-arranged hollow path at a predetermined interval from a plurality of parallel-arranged hollow paths. Furthermore, although the hollow path 2 of this embodiment is linear, for example, one or a plurality of corrugated pipes may be arranged, or one or a plurality of pipes branched into dendrites may be arranged. Various shapes and arrangements, such as different arrangements, can be employed. In any of the above shapes and arrangements, the repair agent is injected into the cracks formed in the concrete structure so that the repair can be sufficiently performed.

  As shown in FIG.1 (b), the hollow path 2 of this embodiment is circular in the cross-sectional shape orthogonal to the direction in which the hollow path 2 extends, but the repair agent can be introduced and discharged, and is generated in the concrete structure. It is not particularly limited as long as the repair agent can be press-fitted into the crack, and various shapes such as a polygon, an indeterminate shape, and a cloud shape can be adopted. Moreover, although the diameter of this cross section changes with kinds etc. of a concrete structure 1, a magnitude | size, arrangement | positioning of the hollow path 2, etc., they are 6 mm or more and 15 mm or less normally.

  The material forming the concrete structure 1 is exposed on the inner wall surface 4 of the hollow path 2 of this embodiment. The material forming the concrete structure 1 is a mixture of at least a concrete raw material composed of fine aggregate, coarse aggregate, cement and water, and the cement and water in the concrete raw material are hydrated over time. It is a concrete material composed of at least fine aggregate, coarse aggregate and cement hydrate.

  The types of fine aggregate, coarse aggregate, cement, and water used as the concrete raw material are not particularly limited, and known raw materials used to form a concrete structure can be used. In addition to fine aggregates, coarse aggregates, cement, and water, as raw materials contained in concrete raw materials, known chemical admixtures, fluidizing agents, rust preventives used to form concrete structures, You may contain admixtures, such as a setting retarder, and admixtures, such as fly ash, blast furnace slag fine powder, and silica fume.

  The moisture blocking region 5 formed on the inner wall surface 4 of the hollow path 2 is preferably formed on at least a part of the inner wall surface 4 by a surface treatment described later, and is formed on the entire inner wall surface 4. The moisture blocking region 5 blocks cement hydrate and other moisture contained in the concrete material from the repair agent introduced into the hollow path 2 to avoid hardening of the repair agent. The moisture blocking region 5 in this embodiment has a form of a layered or film-like cured body having a predetermined thickness, and is in direct contact with the surface of the inner wall surface 4. The form of the moisture blocking region is not limited to a layer shape and a film shape, and is an aspect formed as a region extending from the surface of the inner wall surface 4 toward the inside, and a region and inner wall surface extending from the surface of the inner wall surface 4 toward the inside The aspect etc. which combined the layered or film-shaped hardening body on the surface of 4 can be taken.

  The hollow path 2 can be formed as follows, for example. FIG. 2 is an explanatory diagram for explaining an example of a method for forming a hollow path.

  First, when placing a concrete raw material on a formwork used to form a concrete structure, for example, a steel bar 6 having a predetermined diameter is disposed at a predetermined position (first step). Then, after the concrete raw material is hardened, for example, when ordinary Portland cement is used, the steel rod 6 is pulled out after one or more days have passed since placing. A hollow cylindrical pipe line 7 is formed in the trace where the steel bar 6 has been pulled out (second step). The steel bar 6 is preferably coated with a release agent on the surface before being embedded in the concrete raw material in order to make it easy to pull out from the concrete structure. In this way, the pipe line 7 having the two openings 3a and 3b and the inner wall surface 4 from which the material forming the concrete structure 1 is exposed is formed.

  Next, the surface treatment agent 9 is introduced into the formed pipe line 7 by a compressor or the like, the first opening 3a and the second opening 3b are sealed with the lids 8a and 8b, respectively, and the surface treatment agent 9 is piped. Hold in the path 7 for a predetermined time (third step). Thereafter, the lids 8a and 8b are removed, and the surface treatment agent 9 is discharged from the second opening 3b by applying air pressure from the first opening 3a with a compressor or the like. When the surface treatment agent 9 that has not been discharged from the pipeline 7 is dried, a moisture blocking region 10 is formed on the surface of the inner wall surface 4 of the pipeline 9 (fourth step). The time during which the surface treatment agent 9 is held in the pipe line 7 varies depending on the type of the surface treatment agent 9, but is usually 15 minutes or longer and 60 minutes or less.

  The type of the surface treatment agent 9 is not particularly limited as long as it can form a moisture blocking region that blocks the repair agent introduced into the hollow path and the moisture contained in the concrete. For example, one-component moisture curing that cures at room temperature. One-part moisture-curing resin that cures with moisture in the air, such as type epoxy resin, two-part reaction type polyester resin, two-part reaction type polymethacrylate resin (PMMA), and surface impregnating material. Examples of surface impregnating materials include silane-based, silicate-based, organic resin-based, nitrite-based, and mixed systems thereof. Examples of silane-based materials include alkylalkoxysilanes and alkylsiliconates. . Among these, since the silane-based surface impregnating agent is impregnated from the inner wall surface of the hollow path to form a moisture blocking region, the diameter of the hollow path is not reduced, and it can be kept in the hollow path for a long time. Since it is not cured and has a low viscosity, it is preferable because it is easy to discharge and workability is good.

  For example, when a resin having a low viscosity and easily penetrates into the concrete material is used as the surface treatment agent, the surface treatment agent penetrates from the inner wall surface 4 where the concrete material of the pipe line 7 is exposed, and the surface of the inner wall surface 4 A moisture blocking region 10 having a function of blocking the repair agent and moisture in a predetermined region from the inside to the inside is formed. When the viscosity is relatively high, the surface treatment agent penetrates from the inner wall surface 4 and is formed on the surface of the inner wall surface 4 as a layered or film-like cured film, so that the surface treatment agent is directed from the surface of the cured film toward the inside of the concrete. Thus, a moisture blocking region 10 having a predetermined thickness up to a predetermined depth is formed. FIG. 2 shows an example of the moisture blocking region 10 formed from the surface of the inner wall surface 4 toward the inside.

  The surface treatment agent preferably has a viscosity of 0.5 mPa · s, 23 ° C. or more and 10,000 mPa · s, 23 ° C. or less, and 0.5 mPa · s, 23 ° C. or more and 2,000 mPa · s, 23 ° C. or less. Is particularly preferred. When the viscosity of the surface treatment agent is within the above range, it is easy to form a thin moisture barrier region on the entire inner wall surface of the hollow path.

  Thus, the hollow path 2 having the inner wall surface 4 where the material forming the two openings 3a and 3b and the concrete structure 1 is exposed and the moisture blocking region 10 on the surface of the inner wall surface 4 is formed.

  In the above, although the method in which the pipe line 7 is formed using the steel rod 6 was described, the forming method is not limited to the method using the steel rod, and for example, it can be formed by a method using a rubber tube. . As a method of forming the pipe line 7 using a rubber tube, for example, when placing a concrete raw material on a mold used to form a concrete structure, the rubber tube is arranged at a predetermined position. More than a day has passed since the concrete material was hardened after applying a certain pressure in the rubber tube so that the rubber tube would not be crushed by the weight of the concrete material. Then there is a method of pulling out the rubber tube. When a rubber tube is used, a bent pipe line can be easily formed, and therefore, for example, a pipe line communicating with a beam and a column is easily formed.

  Next, a crack repairing method for a concrete structure in which a hollow path has been formed by the above method will be described.

(First embodiment)
FIG. 3 is an explanatory diagram for explaining an example of a crack repairing method for a concrete structure.

  A concrete structure 1 having the same structure as the concrete structure 1 shown in FIG. 1 is shown in FIG. 3A, and a repair method of the concrete structure 1 will be described. First, the repair agent 11 is introduced from the first opening 3 a of the hollow path 2 using, for example, the compressor 13. The time when the repair agent 11 is introduced is the time when cracks are found on the surface of the concrete structure 1 or when the cracks are expected to occur in the concrete structure 1. At this time, the second opening 3 b is sealed by the plug 12. In the hollow path 2, the repair agent 11 is accommodated over a period of 1 hour to 6 hours while being held at 0.05 Pa to 0.2 Pa by the compressor 13 (Step I). When the repair agent 11 is held in the hollow passage 2 at a predetermined pressure for a predetermined period, the repair agent 11 is pressed into the crack 14 formed in the concrete structure 1. It can be confirmed that the repair agent has been pressed into the crack by leaking the repair agent onto the surface of the concrete structure (step II). In addition, the concrete structure shown by Fig.3 (a)-FIG.3 (c) has shown typically the example which the crack generate | occur | produced when the tensile force generate | occur | produced in the concrete structure.

  The repair agent 11 is a substance that fills and cracks in concrete cracks and cures, and prevents a decrease in yield strength of the concrete structure due to the cracks. For example, the repair agent 11 is a moisture in the air such as a one-component moisture-curing epoxy resin that cures at room temperature. One-component moisture-curing resin that cures can be mentioned. When the epoxy resin is pressed into a crack, it hardens by reacting with moisture of hydrate such as calcium hydroxide contained in the concrete material. As a result, the strength of the concrete structure can be maintained by preventing the strength of the concrete structure from being lowered and neutralized.

  The viscosity of the repair agent is preferably 50 mPa · s, 23 ° C. or more and 14,000 mPa · s, 23 ° C. or less, more preferably 50 mPa · s, 23 ° C. or more and 2,000 mPa · s, 23 ° C. or less. It is preferably 50 mPa · s, 23 ° C. or more and 250 mPa · s, 23 ° C. or less. If the viscosity of the replenisher is 50 mPa · s, 23 ° C. or more and 250 mPa · s, 23 ° C. or less, even if the diameter of the hollow passage is relatively small, the repair agent can be easily discharged from the hollow passage, so that the hollow passage is blocked. Without repeated, the repair agent can be repeatedly introduced into the hollow path. Moreover, since the repair agent can be filled even in a small crack having a crack width of about 0.1 mm, the crack can be reliably repaired.

  Next, after the repair agent 11 is introduced into the hollow path 2, the plug body 12 is removed after a lapse of a predetermined period, and the repair agent 11 is discharged from the second opening 3 b by air pressure by the compressor 13 (step III). At this time, the epoxy resin remaining in the hollow path is not completely cured because the moisture is blocked by the moisture blocking region. Therefore, most of the repair agent 11 present in the hollow path 2 is discharged, and the hollow path 2 is not blocked. In this way, the crack 14 formed in the concrete structure 1 is repaired.

  For example, when the repair agent 11 is introduced into the hollow path 2, for example, when the crack 14 is assumed to occur in the concrete structure 1, the repair agent 11 is periodically introduced into the hollow path 2, for example, every five years. Alternatively, the repair agent 11 may be introduced into the hollow path 2 irregularly after the crack 14 is found on the surface of the concrete structure 1. The timing of discharging the repair agent 11 from the hollow path 2 may be after the repair agent 11 is reliably filled in the crack 14.

  According to the repair method, since the hollow passage 2 is not closed even after the repair work is completed, the crack is generated in the concrete structure 1 after a predetermined period of time, or when the crack is expected to occur. In addition, the crack can be repaired by introducing a repair agent into the hollow path and press-fitting the crack into the crack. Therefore, repeated cracks can be repaired.

(Second embodiment)
FIG. 4 is an explanatory diagram for explaining another example of a crack repairing method for a concrete structure.

  A concrete structure 1 having the same structure as the concrete structure 1 shown in FIG. 1 is shown in FIG. 4A, and a repair method of the concrete structure 1 will be described. First, the repair agent 11 is introduced from the first opening 3a in the same manner as the repair method of the first embodiment. The time when the repair agent 11 is introduced is after the concrete raw material has been placed and hardened, and is assumed to be free from cracks (step i). The inside of the hollow path 2 is maintained at 0.05 Pa or more and 0.2 Pa or less by the compressor 13 for several years until the time when cracks are expected to occur, for example. In the meantime, when cracks 14 occur in the concrete structure 1 and cracks 14 occur simultaneously on the inner wall surface 4 (step ii), the repair agent 11 is press-fitted from the cracks 14 formed on the inner wall surface 4, and the repair agent 11 is cured by reacting with moisture of hydrates such as calcium hydroxide contained in the concrete (step iii). In this way, the crack 14 formed in the concrete structure 1 is repaired. In addition, the concrete structure shown by Fig.4 (a)-FIG.4 (c) has shown typically the example which the crack generate | occur | produced when tensile force generate | occur | produced in the concrete structure.

  According to the repair method, the repair agent is introduced into the hollow path before cracking occurs in the concrete structure, and is maintained at a predetermined pressure. Therefore, when cracks occur in the concrete structure, cracks also occur on the inner wall surface at the same time. The repair agent which is formed and exists in the hollow passage through the crack formed in the inner wall surface is pressed into the crack in the concrete structure. Therefore, the crack generated in the concrete structure is self-repaired without using the conventional work procedure of repairing the crack detected after the crack inspection.

(Third embodiment)
FIG. 5 is an explanatory diagram for explaining another example of a crack repairing method for a concrete structure. Fig.5 (a) is sectional explanatory drawing of a concrete structure, FIG.5 (b) is a side view at the time of seeing the concrete structure shown to Fig.5 (a) from B direction.

  A concrete structure 31 shown in FIG. 5A has a first hollow path 15 having a hollow cylindrical shape similar to the hollow path 2 in the concrete structure 1 shown in FIG. A plurality of second hollow passages 16, third hollow passages 17, and fourth hollow passages 18 having the same shape are arranged in parallel at equal intervals without crossing each other. Thus, the repair method of the concrete structure 31 which has the some hollow paths 15-18 from which a path | route differs is demonstrated.

  First, the repair agent is introduced from the first openings 19a, 20a, 21a, and 22a in the same manner as the repair method of the first embodiment. The repair agent uses two types of first repair agent 23 and second repair agent 24 having different viscosities, and these two types of first repair agent 23 and second repair agent 24 are arranged in a concrete structure 31. The repairing agents having the same viscosity are alternately introduced into the hollow passages 15 to 18 so as not to be adjacent to each other. For example, the first hollow path 15 and the third hollow path 17 introduce the first repair agent 23 having a low viscosity, and the second hollow path 16 and the fourth hollow path 18 are the second having a higher viscosity than the first repair agent 23. The repair agent 24 is introduced. The low viscosity repair agent is, for example, 50 mPa · s, 23 ° C. or more and 250 mPa · s, 23 ° C. or less, and the high viscosity repair agent is, for example, 1500 mPa · s, 23 ° C. or more and 14,000 mPa · s, 23 ° C. The following repair agents can be mentioned.

  The timing of introducing the repairing agents 23 and 24 may be after the occurrence of cracks as in the repair method of the first embodiment, or even before the occurrence of cracks as in the repair method of the second embodiment. Good. About the period when the repair agent is held in the hollow passages 15 to 18 and the pressure, etc., depending on the kind of the repair agent and the timing of introducing the repair agent, the repair method of the first embodiment or the second embodiment described above. This is performed by the method exemplified in the repair method. Thus, the crack formed in the concrete structure 31 is repaired.

  According to the repair method, a repair agent having a low viscosity is easily filled into a crack having a small crack width, and a repair agent having a different viscosity is more likely to be filled into a crack having a large crack width as the viscosity of the repair agent increases. Therefore, it is possible to press-fit the repair agent to every size of cracks regardless of the crack width. As a result, it is possible to reliably repair cracks inside and on the surface of the concrete structure.

  According to the crack repairing method according to any of the above embodiments, it is possible to repair the cracks formed on the surface and inside of the concrete structure only by introducing a repair agent into the hollow path formed in the concrete structure. There is no need to inspect cracks. Therefore, it is possible to reduce the labor and cost of crack inspection. In addition, fine cracks that are easily overlooked can be repaired.

  Further, in the crack repairing method according to any of the above embodiments, since the hollow path is arranged in the concrete structure, a repair agent is introduced from the opening of the hollow path at a place away from the crack generation place and press-fitted into the crack. can do. Therefore, it is possible to repair the cracks safely from a place where it is difficult to inspect and repair the cracks, for example, a wall of a nuclear waste treatment facility or a nuclear power plant.

  The concrete structure and the crack repairing method according to the present invention are not limited to the above-described embodiments, and various modifications are possible within the scope that can achieve the object of the present invention.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

<Strength recovery rate by repairing cracks>
According to the test procedure shown in FIG. 6, a repair agent was injected into a mortar specimen provided with a hollow path, and the bending strength before and after crack repair was measured.

(Preparation of mortar specimen)
A mortar specimen was prepared instead of concrete, and the concrete structure of the present invention and its crack repair method were evaluated using the mortar specimen. The cement used is ordinary Portland cement specified in JIS R 5210, the fine aggregate is Toyoura cinnabar, cement: fine aggregate = 1: 3 (mass ratio), and the water cement ratio is 72%. Aggregate and water were kneaded to prepare a mortar. This mortar was driven into a 40 × 40 × 150 mm mold, a steel rod having a diameter of 6 mm was placed in the center, and curing was performed for 28 days (first curing). The conditions for the first curing are wet curing for 2 days (temperature 20 ° C., humidity 90% RH), curing for 5 days in water, and then drying curing for 21 days (temperature 20 ° C., humidity 60% RH).

  After the completion of the first curing, the steel rod was pulled out to obtain a mortar hardened body in which one hollow path having two openings was arranged.

  The surface treatment agent shown in Table 1 was filled in the cylinder, and the surface treatment agent filled in the cylinder was introduced from the opening of the hollow passage provided in the mortar cured body. The opening provided on the side opposite to the opening into which the surface treatment agent was introduced was sealed with a putty. The silane-based surface impregnating agent was held for 30 minutes, and the one-component moisture-curing epoxy resin was held in the hollow path for 15 minutes and then discharged. . In this way, three mortar specimens each having a moisture blocking region formed on the inner wall surface of the hollow channel were formed for each example.

(Injecting repair agent)
Fill the cylinder with the repair agent shown in Table 2, introduce the repair agent filled into the cylinder from the opening of the hollow passage provided in the mortar specimen, attach rubber to the cylinder, and constantly apply pressure to the hollow passage. I was in a state. The opening provided on the side opposite to the opening into which the repair agent was introduced was sealed with a putty. After injecting the repair agent, it was dried and cured (temperature 20 ° C., humidity 60% RH) for 28 days (second curing).

(Crack formation)
After the second curing, in accordance with JIS R 5201 (cement physical testing method), perform a bending test using a fully automatic compression tester and mechanically control the load from reaching the maximum load to breaking. Thus, a crack having a crack width of 0.05 mm to 0.20 mm was formed on the mortar specimen. The bending strength when reaching the maximum load is shown in Table 3 as the bending strength of the first load. Table 3 shows the average value of the bending strength of the three mortar colloids.

(Third curing)
As described above, after forming cracks in the mortar specimen, accelerated curing was performed (third curing). The curing conditions of the third curing are 5 days dry curing (temperature 20 ° C., humidity 60% RH), 4 hours autoclave curing (temperature 50 ° C.), 20 hours curing with a dryer (temperature 50 ° C.), then 1 It is a daily dry curing (temperature 20 ° C., humidity 60% RH).

  After completion of the third curing, the putty and the cylinder were removed, and the repair agent filled in the hollow path was discharged by sending air pressure into the hollow path with a compressor.

(Bending strength test)
After discharging the repairing agent, a bending test was performed using a fully automatic compression tester according to JIS R 5201 (cement physical testing method), and the bending strength was measured. The measured values at this time are shown in Table 3 as the bending strength of the second load. Table 3 shows the average value of the bending strength of the three mortar colloids.

  The bending strength of the first load measured when the crack was formed was compared with the bending strength of the second load measured after the third curing, and the strength recovery rate was calculated according to the following calculation formula. The results are shown in Table 3.

C = (B / A) × 100 (%)
A: Bending strength of first load (N / mm ² )
B: Bending strength of second load (N / mm ² )
C: Strength recovery rate (%))

  In the mortar specimens of Examples 1 to 4 within the scope of the present invention, the bending strength was recovered after repairing the cracks. On the other hand, the bending strength recovery rate of the mortar specimen of Comparative Example 1 which does not have the moisture blocking region and is outside the scope of the present invention was low. This is considered to be because the repairing agent was hardened in the hollow passage and the repairing agent was not sufficiently filled in the cracks.

<Change in diameter of hollow channel>
According to the test procedure shown in FIG. 7, the repair agent was injected into the mortar specimen provided with the hollow passage, and the diameter of the hollow passage before and after introducing the repair agent into the hollow passage was measured.

  First, 12 mortar specimens were produced in the same manner as in Example 1.

  Subsequently, the bending test of the 1st loading was done like Example 1, and the crack was formed in the mortar specimen.

  Next, after injecting the repairing agent shown in Table 4 in the same manner as in Example 1, after drying and curing for one day (temperature 20 ° C., humidity 60% RH), the hollow path was filled by sending air pressure into the hollow path with a compressor. The repair agent that has been discharged.

  Next, accelerated curing was performed. The conditions of accelerated curing are wet curing (temperature 20 ° C, humidity 90% RH) for 4 days, then autoclave curing (temperature 50 ° C) for 4 hours, curing in a dryer (temperature 50 ° C) for 20 hours, and then for 1 day. Dry curing (temperature 20 ° C., humidity 60% RH).

  Next, six of the prepared mortar specimens were subjected to a bending test (second loading) using a fully automatic compression tester according to JIS R 5201 (cement physical test method), and then using an electric cutter. Cut the mortar specimen into four equal parts in the direction perpendicular to the hollow channel, measure the diameter of the two orthogonal directions of the hollow channel at each cut surface, and use the arithmetic average value of all measured values as the diameter of the hollow channel Table 4 shows.

  Further, with respect to the remaining six mortar specimens, the operations from the above-mentioned repair agent injection to the bending strength test (third load) and the measurement of the diameter of the hollow path were repeated. Indicated.

  After introducing and discharging the repair agent into and out of the hollow passage having a diameter of 6 mm, the repair agent is introduced and discharged again after a predetermined period, and the hollow passage is not blocked for any of the repair agents B and C having different viscosities. It was. From this result, when a crack occurs in a concrete structure, the repair agent can be discharged after the repair agent is introduced into the hollow passage and repaired, and the hollow passage is not blocked, so that the crack can be repaired repeatedly. It has been shown.

<Relationship between viscosity of repair agent and crack width>
In accordance with the test procedure shown in FIG. 8, two kinds of repair agents having different viscosities were introduced into a mortar specimen provided with a hollow channel, and the crack width and the bending strength before and after the crack repair were measured.

  First, 18 mortar specimens were produced in the same manner as in Example 1.

  Subsequently, the bending test of the 1st loading was done like Example 1, and the crack was formed in the mortar specimen. The bending strength when the maximum load is reached is shown in Table 5 as the bending strength of the first load. The crack width of the formed crack was measured by applying a crack scale to the crack on the surface where the crack began to occur.

  Next, after injecting the repairing agent shown in Table 5 in the same manner as in Example 1, the film was dried for 1 day (temperature 20 ° C., humidity 60% RH), and then filled into the hollow path by sending air pressure into the hollow path with a compressor. The repair agent that has been discharged.

  Subsequently, the mortar specimen after discharging the repair agent was dried and cured (temperature 20 ° C., humidity 60% RH) for 7 days.

  Next, the mortar specimen after dry curing was subjected to a bending test (second loading) using a fully automatic compression tester according to JIS R 5201 (cement physical test method), and the bending strength was measured. The measured values at this time are shown in Table 5 as the bending strength of the second load.

  Further, in the same manner as in Example 1, the strength recovery rate of the bending strength of the second load with respect to the bending strength of the first load was calculated and shown in Table 5.

  When repairing a crack having a crack width in the range of 0.10 to 0.34 (mm) using the repair agent C having a low viscosity, the strength recovery rate of the mortar specimen was high. On the other hand, when repairing a crack having a crack width in the range of 0.10 to 0.36 (mm) using repair agent B having a higher viscosity than repair agent C, the strength recovery of the mortar specimen having a small crack width is achieved. The rate was not enough. From this result, it is presumed that the crack recovery with a smaller crack width is more easily filled with the low-viscosity repair agent, and the strength recovery rate is increased by sufficiently filling the crack with the repair agent.

DESCRIPTION OF SYMBOLS 1 Concrete structure 2,15,16,17,18 Hollow path 3a, 3b, 19a, 19b, 20a, 21a, 22a Opening part 4 Inner wall surface 5,10 Moisture blocking area 6 Steel bar 7 Pipe lines 8a, 8b Lid 9 Surface treatment agent 11, 23, 24 Repair agent 12 Plug body 13 Cylinder 14 Crack

Claims (7)

An opening into which a repair agent is introduced into the concrete structure, an inner wall surface from which a material forming the concrete structure is exposed, and the repair agent and moisture formed on the surface of the inner wall surface by surface treatment. Forming a hollow path with a moisture blocking region to block,
A method for repairing a crack in a concrete structure, wherein the repair agent is introduced into the hollow passage from the opening and the repair agent is press-fitted into a crack formed in the concrete structure.   The method for repairing a crack in a concrete structure according to claim 1, wherein the repair agent is discharged from the hollow path after the repair agent is press-fitted into the crack.   3. The moisture blocking region is formed of at least one surface treatment agent selected from the group consisting of a one-component moisture curable epoxy resin that cures at room temperature and a surface impregnating material. The crack repair method of the concrete structure as described in 4.   The method for repairing cracks in a concrete structure according to any one of claims 1 to 3, wherein the repair agent is a one-component moisture-curing epoxy resin that cures at room temperature.   The said repair agent has the 1st repair agent and 2nd repair agent from which a viscosity differs, The said 1st repair agent and the said 2nd repair agent are each introduce | transduced into the hollow path from which a path | route differs. The crack repair method of the concrete structure as described in any one of 1-4.   An opening into which a repair agent is introduced, an inner wall surface from which a material forming a concrete structure is exposed, and a moisture blocking region formed by surface treatment on the surface of the inner wall surface to block the repair agent from moisture A concrete structure characterized by having a hollow passage provided with.   The moisture blocking region is formed of at least one surface treatment agent selected from the group consisting of a one-component moisture-curing epoxy resin that cures at room temperature and a surface impregnating material. Concrete structure.

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