JP2009019440A - Method for repairing concrete waterway with joint part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for repairing a concrete waterway with joint parts capable of enhancing sealability and preventing water from springing out of a joint part by reducing the compressive force concentrated on the joint part when the cross section of a waterway structure is repaired by forming thin its wall thickness. <P>SOLUTION: A block out 4 is formed in the front surface of an existing concrete on both sides of the joint part 2 of an existing concrete waterway skeleton 1. A non-adhered band 5 astride the joint part 2 is fitted to the bottom surface of the through hole 4. The portion of the block out 4 and the front surface part of the existing concrete 6 are filled or coated with a highly rigid fiber-reinforced cement compound material (highly tough FRC material). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for repairing a concrete waterway having a joint for reducing the compressive force concentrated on the joint when the repair is thin and repaired in a cross-section of the waterway structure.

  As shown in FIG. 2, in an agricultural channel which is a channel structure, there are members of an existing concrete channel 1 and joints 2 (joints) of members, and in an aged channel, spring water 3 from the joints 2 is present. It is a problem.

In the following Patent Document 1, a water-based resin-based adhesive is applied to the surface of a non-aged portion of a water channel that has been ground-treated in the ground treatment process, as an efficient recovery of an aged concrete water channel to the same function as at the time of construction. It is described that the surface of a water channel is neutralized by applying an agent, and a highly elastic special mortar having high adhesion is applied after drying.
JP 2006-16789

Moreover, while the countermeasure against repair of an aged waterway joint is calculated | required, there exists the following patent document 2 as an effective water leakage prevention countermeasure in the joint development part for concrete agriculture, and the joint part of a waterway tunnel.
JP 2005-128180

  In this patent document 2, a joint part of a concrete structure such as a waterway or a waterway tunnel is adapted to the shape of the water leakage prevention seal material, processed or formed, and then the water leakage prevention seal material is placed at a predetermined position of the joint part. It can be easily loaded and does not generate a tensile stress on the upper surface and the surface of the water leakage prevention sealing material. As shown in FIG. 3, the joint portion 18 formed at the joint of the concrete structures 17 and 17 is unboxed. Specifically, the stepped surfaces 17b and 17b as the upper surface opening 18a, the wall surface 17a and 17a as the intermediate portion 18b connected to the stepped surface 17b, and the deep portion 18c having a substantially mountain shape in cross section of the joint portion 18 connected to the wall surfaces 17a and 17a. Is processed or formed. Then, an adhesive 21 such as an epoxy resin is sealed in the wall surfaces 17a and 17a or the stepped surfaces 17b and 17b to perform filling and sealing. Thus, the sealing material 19 for preventing water leakage is loaded into the joint portion 18.

  In Patent Document 1, repair with a relatively thin wall is possible, but consideration is not given to the joint portion, and the compressive force concentrated on the joint portion cannot be reduced.

  Although patent document 2 can cope with the spring water from a joint part, this is performed by unboxing the joint part and disposing a sealing material for preventing water leakage there. The concentrated compression force cannot be reduced.

  The object of the present invention is to eliminate the inconvenience of the conventional example, and to reduce not only the sealing performance but also the compressive force concentrated on the joint when the repair is thin in the cross section repair of the water channel structure. Then, it is providing the repair method of the concrete waterway which has a joint part which can prevent the spring from a joint part.

In order to achieve the above object, the present invention according to claim 1, wherein the boxing is formed on the existing concrete surface layer straddling the joint part of the existing concrete waterway frame, and a non-adhesive zone is provided on the bottom surface of the box to straddle the joint part. A crack dispersion type in which tensile strain is 1% or more in a tensile test of a cured product on the age of 28 days, and a PVA (Polyvinyl Alcohol) short fiber of [F1] below is added to the formulation matrix of [M1] by more than 1 3 Vol. The high-toughness fiber-reinforced cement composite material (high-toughness FRC material) blended three-dimensionally or two-dimensionally randomly is filled or applied to the boxed portion and the existing concrete surface portion with a blending amount of 1%. Is.
[M1]
-Water binder ratio (W / C) 25% or more-Sand binder weight ratio (S / C) is 1.5 or less (including 0)
Fine aggregate maximum particle size 0.8mm or less, average particle size 0.4mm or less,
Unit water volume 250 kg / m ³ or more and 400 kg / m ³ or less High-performance AE water reducing agent amount 30 kg / m ^{3 or} less [F1]
Fiber diameter 50 μm or less Fiber length: 5-20 mm
Fiber tensile strength: 1500 MPa to 2400 MPa or less

  Since temperature stress (compression, tension) with age change of concrete acts on the joint part, in most cases, conventional mortar and concrete are cracked at the initial stage of installation, and spring water is generated from the joint part.

  According to the first aspect of the present invention, the high-toughness fiber-reinforced cement composite material (high-toughness FRC material) has a tensile strain exceeding 1% due to its formulation matrix and fiber blending amount. Direction) and a crack dispersion type fracture phenomenon in which a large number of cracks (multi-cracks) are generated in a direction substantially perpendicular to the direction. Therefore, cracks can be reliably controlled to a minute width, and such a high-toughness fiber-reinforced cement composite material (high-toughness FRC material) should be used to reduce local stress concentration at joints. Thus, strain hardening is exhibited under uniaxial tension, and a plurality of fine and high-density cracks are formed. As a result, local breakage due to stress concentration at the joint can be eliminated.

  Specifically, for tensile force, the non-adhesive section is provided between the existing concrete near the joint and the high-toughness fiber-reinforced cement composite material, thereby cracking the high-toughness fiber-reinforced cement composite material. It is possible to reduce the stress by utilizing the action, and to reduce the compressive force by providing a thick tough fiber-reinforced cement composite near the joint.

  Note that the stress concentration at the corners by providing grooves by boxing can be dispersed in a thin part to be applied to the existing concrete surface part other than the joint part of the high-toughness fiber-reinforced cement composite material. So there is no problem. If there is an adverse effect, it may be tapered.

  In the present invention according to claim 2, the depth of the box opening part is in the range of 0.001 L to 0.05 L with respect to the water channel span L, and the tough fiber-reinforced cement composite material applied to the existing concrete surface part. The gist of this is that the thickness is 5 mm or more.

  According to the second aspect of the present invention, by securing the member thickness of the high-toughness fiber-reinforced cement composite material in the vicinity of the joint portion to 10 mm or more, the resistance stress can be increased and the local fracture can be avoided. In addition, by setting the thickness of the thin repaired part to be 5 mm or more, it shows strain hardening under uniaxial tensile stress and forms multiple fine and high-density cracks. Even if this occurs, it is possible to realize a surface protective work that retains the function.

  In general mortar with low elongation performance, cracks occur at the boundary where the joint is thickened and thinned, but the high-toughness fiber reinforced cement composite material has high elongation performance. Even if a certain amount of tensile force is applied, large cracks do not occur.

  The gist of the present invention described in claim 3 is that the width of the box opening portion is in the range of 0.001 L to 0.05 L with respect to the water channel span L.

  According to the third aspect of the present invention, since the high-toughness fiber-reinforced cement composite material and the existing concrete adhere to each other at a thick portion, the stress is not concentrated locally but dispersed as a whole. A range of 0.001 L to 0.05 L with respect to the water channel span L can secure a necessary width.

According to the present invention, the high toughness fiber-reinforced cement composite material has a compressive stress of 30 N / mm ² and a tensile ultimate strain of 0.2% or more, and a crack width at the time of maximum load action is 0.2 or less. It is a summary.

According to the fourth aspect of the present invention, in order to ensure the crack dispersibility of the high-toughness fiber-reinforced cement composite material, the magnitude of the compressive strength is largely attributed to the crack dispersibility, so that it is about 30 N / mm ^2. The formulation was selected as follows. In addition, the elastic limit of general steel materials is 0.2%, and when high-toughness fiber reinforced cement composite material is used as a composite structure with steel material, it has reinforcement with ECC having an ultimate strain of 0.2%. The effect can be expected, and further, by making the crack width at the maximum load action 0.2 mm or less, the crack width that generally requires repair of the structure is not reached.

  The gist of the present invention described in claim 5 is to select a non-adhesive band that straddles the joint part, such as silicon or vinyl tape, that completely adheres to the existing concrete.

  According to the fifth aspect of the present invention, a high-toughness fiber-reinforced cement is provided by providing a non-adhesive section between the existing concrete near the joint and the high-toughness fiber-reinforced cement composite material for tension. Although the stress can be reduced by utilizing the crack dispersion action of the composite material, the non-adherent zone is selected so that the non-adherent zone is completely disconnected from the existing concrete, so that the completeness of the effect can be expected. can do.

  The gist of the present invention described in claim 6 is that the surface of the high-toughness fiber-reinforced cement composite material to be filled in the box opening portion and the fiber-reinforced cement composite material to be applied to the existing concrete surface portion are made continuous.

  According to the sixth aspect of the present invention, the synergistic effect of both can be ensured by continuously connecting the compressive force reducing portion made of the fiber-reinforced cement composite material and the thin repair portion made of the fiber-reinforced cement composite material. And the appearance will be good.

  As described above, the repair method for a concrete water channel having a joint part according to the present invention concentrates on the joint part as well as improving the sealing performance when the repair is thin in the cross-section repair of the water channel structure. By reducing the compression force, spring water from the joint can be prevented.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal front view showing an embodiment of a repair method for a concrete waterway having a joint according to the present invention.
This is a case of an agricultural waterway as the waterway structure. In the figure, 1 indicates an existing concrete waterway frame, and there are a member and a joint part 2 (seam) of the member.

  In the present invention, a box opening 4 is formed on the surface layer of the existing concrete 6 across the joint portion 2 of the existing concrete waterway frame 1, and a non-adhesive zone 5 is provided on the bottom surface of the box opening 4 to straddle the joint portion 2. The fiber reinforced cement composite material (high toughness FRC material) is filled or applied on the portion of the boxing 4 and the surface portion of the existing concrete 6, and the portion of the boxing 4 is made by the repaired portion of the high toughness fiber reinforced cement composite material. The compressive force reducing portion 7 was used, and the surface portion of the existing concrete 6 was a thin tough repair portion 8 of a high-toughness fiber-reinforced cement composite material. In the figure, 9 is water.

  As the non-adhesion zone 5 straddling the joint portion 2, a material such as silicon or vinyl tape that adheres completely to the existing concrete 6 is selected.

  The filling or application of the high-toughness fiber-reinforced cement composite material may be performed by pouring or spraying.

A high-toughness fiber-reinforced cement composite material (high-toughness FRC material) is a crack dispersion type in which a tensile strain is 1% or more in a tensile test of a hardened material on the 28th day of the material age, and is PVA (Polyvinyl) of the following [F1]. Alcohol) short fibers were added to the formulation matrix of [M1], exceeding 1 to 3 Vol. % Blended in a three-dimensional random or two-dimensional random manner.
[M1]
-Water binder ratio (W / C) 25% or more-Sand binder weight ratio (S / C) is 1.5 or less (including 0)
Fine aggregate maximum particle size 0.8mm or less, average particle size 0.4mm or less,
Unit water volume 250 kg / m ³ or more and 400 kg / m ³ or less High-performance AE water reducing agent amount 30 kg / m ^{3 or} less [F1]
Fiber diameter 50 μm or less Fiber length: 5-20 mm
Fiber tensile strength: 1500 MPa to 2400 MPa or less

  In order to be suitable for spray construction, the amount of air at the time of kneading may be 3.5% or more and 20% or less in the [M1] preparation matrix, but it is preferable to set this to 20% or more.

  In order to increase the amount of air entrainment, air-entraining admixtures such as AE agents, AE water reducing agents, and high-performance AE water reducing agents are used when mixing high-toughness fiber-reinforced cement composite materials (high-toughness FRC materials) 2 .

  The air-entraining admixture that can be used is an admixture that can entrain fine closed cells in the cement formulation, and is capable of entraining 3 to 6 vol% of closed cells having a diameter of 250 μm or less, preferably 20 to 200 μm.

  Examples of such air-entraining admixtures include AE agent of JIS A6204 (chemical admixture for concrete), AE water reducing agent or high performance AE water reducing agent, and compounds having the same performance as those, and use commercially available products. You can also These may be used alone or in combination of two or more.

  Examples of the AE agent include soap-based AE agents such as fatty acid salts, resin acid salts, and naphthenates; sulfuric acids such as higher alcohol sulfates, polyoxyethylene alkyl ether sulfates, and polyoxyethylene aryl ether sulfates. Ester-based AE agents; Ether-based AE agents such as polyoxyethylene alkyl ether and polyoxyethylene aryl ether, Nonionic AE agents such as polyoxyethylene sorbitan fatty acid ester-based AE agents; Betaine-based AE agents, Imidazoline betaine-based AE agents, etc. These amphoteric surfactant-based AE agents are listed. Some of these have a function as a foaming agent.

  Examples of the AE water reducing agent include lignin sulfonate or a derivative thereof, oxyorganic acid salt, alkylaryl sulfonate, polyoxyethylene alkylaryl ether, polyol complex, sulfonate of higher alcohol, etc. as a main component. And the like. Moreover, if these compounds are main components, the AE agent mentioned above may be partially contained.

  Examples of the high-performance AE water reducing agent include polycarboxylic acid ethers, modified lignin sulfonates, alkylaryl sulfonates, aromatic amino sulfonates, modified naphthalene sulfonates, modified methylol melamine condensates as main components, Examples include compounds containing melamine sulfonate. Moreover, if these compounds are main components, the AE agent or AE water reducing agent mentioned above may be partially contained.

  The tensile strain refers to a strain amount (%) at the maximum tensile stress value in a stress-strain curve obtained by a tensile test of a cured product having a material age of 28 days or more. Actually, it is represented by a tensile strain (%) in a tensile test (for example, a test specimen having a cross section of 30 mm × 13 mm is subjected to a tensile test in an 80 mm test section) on the 28th day of the material age.

  That the tensile strain is 1% or more means that a crack dispersion type fracture phenomenon in which a large number of cracks (multi-cracks) are generated in a direction substantially perpendicular to the loading direction (stress direction).

The high-toughness fiber-reinforced cement composite material has a compressive stress of 30 N / mm ² , a tensile ultimate strain of 0.2% or more, and a crack width at the maximum load action of 0.2 or less.

  The depth of the box opening 4 is in the range of 0.001 L to 0.05 L with respect to the water channel span L. Thereby, the depth of the part of the box opener 4 becomes 10 mm or more. Thus, by ensuring the member thickness of the high-toughness fiber-reinforced cement composite material in the vicinity of the joint portion 2 to be 10 mm or more, the resistance stress can be increased and the local fracture can be avoided.

  Further, the width of the box opening 4 is also in the range of 0.001 L to 0.05 L with respect to the water channel span L.

  It is considered that there is almost no influence on the concentration of stress on the corners when forming the box 4, but if there is an adverse effect, it may be tapered.

  On the other hand, the thickness of the thin repair portion 8 of the high-toughness fiber-reinforced cement composite material on the surface of the existing concrete is 5 mm or more.

  Further, the surface of the high-toughness fiber reinforced cement composite material to be filled in the box opening 4 and the surface of the fiber reinforced cement composite material to be applied to the existing concrete surface portion shall be continuously integrated without providing a step.

It is a vertical front view which shows one Embodiment of the repair construction method of the concrete waterway which has a joint part of this invention. It is explanatory drawing of the agricultural waterway which has a joint part. It is a vertical side view of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Existing concrete waterway frame 2 ... Joint part 3 ... Spring water 4 ... Box extraction 5 ... Non-adhesion zone 6 ... Existing concrete 7 ... Compression force reduction part 8 ... Thin repair part 9 ... Water 17 ... Concrete structure 17a ... Wall surface 17b ... Step surface 18 ... Joint portion 18a ... Opening portion 18b ... Intermediate portion 18c ... Deep portion 19 ... Sealant 21 for preventing water leakage 21 ... Adhesive

Claims (6)

A box is formed in the existing concrete surface layer across the joint part of the existing concrete waterway frame, and a non-adhesive zone is formed on the bottom surface of the box to straddle the joint part. % PVA (Polyvinyl Alcohol) short fiber of [F1] below is added to the formulation matrix of [M1] by more than 1 and 3 Vol. A high-toughness fiber-reinforced cement composite material (high-toughness FRC material) blended three-dimensionally or two-dimensionally randomly is filled or applied to the boxed portion and the existing concrete surface portion at a blending amount of%. Repair method for concrete waterways with joints.
[M1]
-Water binder ratio (W / C) 25% or more-Sand binder weight ratio (S / C) is 1.5 or less (including 0)
Fine aggregate maximum particle size 0.8mm or less, average particle size 0.4mm or less,
Unit water volume 250 kg / m ³ or more and 400 kg / m ³ or less High-performance AE water reducing agent amount 30 kg / m ^{3 or} less [F1]
Fiber diameter 50 μm or less Fiber length: 5-20 mm
Fiber tensile strength: 1500 MPa to 2400 MPa or less   The depth of the box opening part is in the range of 0.001 L to 0.05 L with respect to the water channel span L, and the thickness of the high-toughness fiber-reinforced cement composite material applied to the existing concrete surface part is 5 mm or more. The repair method of the concrete waterway which has the joint part of claim | item 1.   The method for repairing a concrete waterway having joints according to claim 1 or 2, wherein the width of the box opening part is in a range of 0.001L to 0.05L with respect to the waterway span L. The high-toughness fiber-reinforced cement composite material has a compressive stress of 30 N / mm ² , a tensile ultimate strain of 0.2% or more, and a crack width at the maximum load action of 0.2 or less. A repair method for a concrete waterway having a joint part according to any one of the above.   The non-adhesive zone straddling the joint portion is selected from the ones that completely adhere to the existing concrete, such as silicon and vinyl tape, and repairing the concrete water channel having the joint portion according to any one of claims 1 to 4. Construction method.   The concrete having a joint part according to any one of claims 1 to 5, wherein the surface of the high-toughness fiber-reinforced cement composite material to be filled in the box opening part and the fiber-reinforced cement composite material to be applied to the existing concrete surface part are made continuous. Repair method for waterworks.

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