JP4995774B2 - Crack-inducing joint, crack-inducing waterproof structure and method for concrete structure using the same - Google Patents

Description

The present invention, crack-induced joint relates cracks induced waterproof structure and method of concrete structures. More specifically, the crack-inducing joint has a screwing groove extending in the vertical direction, and the joint fixing screw has a co-rotation preventing mechanism, so that the crack-inducing joint can be easily and quickly fixed to the formwork, Furthermore, a crack-inducing joint left in the concrete structure, which can generate a crack at a predetermined location inside the concrete structure and waterproof it, and a crack-induced waterproof structure and method for a concrete structure using the same About.

  Cracks are generated on the surface and inside of the reinforced concrete structure due to shrinkage stress accompanying hardening of the cast concrete. The cracks are randomly generated in many places depending on the curing conditions. It is known that when cracks appear on the outer surface of the concrete, not only the appearance is impaired, but moisture penetrates into the cracks, and the invaded moisture causes corrosion and deterioration of the internal reinforcing bars, thereby reducing the strength of the concrete structure. . Therefore, cracks can be generated by forming crack-inducing joints at predetermined locations on the surface of the concrete structure to create cross-sectional defects, or by forming crack-inducing structures inside the concrete structure and concentrating stress at those locations. Conventionally, a technique for actively concentrating and generating a specific location and preventing a large number of other locations from occurring randomly has been employed. By using such a method, the waterproof work for the crack is facilitated.

  As an example of a joint that causes a cross-sectional defect portion, Patent Document 1 discloses a resin crack-inducing joint that is left in a concrete structure. By arranging such joints in the concrete structure so that they face each other, cracks are induced between the joints facing each other, and the periphery of the joints is covered with an adhesive material. Water can be prevented from entering. In Patent Document 2, a crack inducing member is embedded in a concrete structure, a crack is generated in a presumed portion inside the concrete structure, and a repair agent is injected from a slit provided in the crack inducing member. A crack-induced waterstop structure that can repair a crack is disclosed. Further, Patent Document 3 discloses a crack-inducing joint provided with a pipe for injecting a repairing agent into the generated crack as having the functions of the crack-inducing joint and the crack-inducing water stop structure. ing.

JP 2002-161544 A Registered Utility Model No. 31216658 JP-A-9-184206

  However, the residual type induction joint as disclosed in Patent Document 1 cannot repair a crack generated in the concrete structure itself. Therefore, when repairing a crack that has occurred, it is necessary to provide a drill that leads to the crack from the outside of the concrete structure with a drill or the like, and to inject a repair agent into the crack from the drill, which increases the number of work steps when repairing the crack. It has the problem that it ends up.

  Further, the joint is fixed to the inside of the mold by screws or the like before placing the concrete. However, it takes time to align the screw hole provided in the mold with the screw hole provided in the joint. Also, if the gap between the screw holes in the mold and the screw holes in the joints are misaligned, or if there are obstacles such as steel pipes that fix the mold around the screw holes, re-open the holes at the work site. It must be possible to fix it, which causes a delay in work.

  Moreover, when using a nail for fixing a joint and a formwork, a nail must be removed considering that a joint is left in a concrete structure after concrete placement, and the burden of removal work is large. In addition, after the nail is removed, the appearance of the joint exposed on the outer surface of the concrete structure remains unsatisfactory.

  In addition, in the case of embedding a crack-inducing water stop structure inside a concrete structure, the crack-inducing water stop member must be fixed to the reinforcing bar inside the concrete structure in advance before placing the concrete.

  The present invention solves these problems, and it is possible to easily and quickly fix the crack-inducing joint to the formwork by the joint fixing screw, and leave the crack-inducing joint in the concrete structure, so that a cross-sectional defect portion occurs. Without cracking, the cracks are generated at the assumed locations inside the concrete structure, and the cracks that are generated are filled with a repair agent to be waterproof, thereby reliably preventing water from entering the concrete structure. It is an object of the present invention to provide a crack-inducing joint, joint fixing screw, crack-inducing waterproof structure and method capable of preventing the strength of the structure from being lowered for a long time.

The crack-inducing joint of the present invention is attached to a formwork for placing concrete, and is left in the concrete structure so as to be exposed to the outer surface of the concrete structure after placing the concrete. and joint body, a crack induced joint and a coating layer of the adhesive material covering the crack inducing joint body, the cracks induced joint body, and facing said mold, its arbitrary cross-sectional shape, flat and parts, consists of a tapered portion that tapers as going to the opposite side of the flat portion, the flat surface formed from the flat portion, open to the flat surface, any cross-section wider than the inner width of the opening width shape provided screwed groove of T-shaped, the said screw groove, from the opening of the flat surface side of the screw groove, joint fixing screws are detachable, the tip of the tapered portion, the click Provided with an opening groove that communicates the upper end surface and the lower end surface of the crack-inducing joint body, the opening of the opening groove is covered with a sheet that does not transmit uncured concrete, and the covering layer is formed on the crack-inducing joint body. A surface other than the upper end surface, the lower end surface, the flat surface, and the opening groove is covered.

  Moreover, it is preferable to provide protrusions having a width of 0.1 to 5 mm and a height of 0.1 to 1 mm on the left and right ends of the flat surface.

  Moreover, it is preferable to provide at least one protrusion having a height of 1 to 12 mm on the surface of the crack-inducing joint that contacts the concrete.

  Moreover, it is preferable to integrally form a cylinder along the longitudinal direction of the crack-inducing joint body at the tip of the tapered portion.

  In addition, it is preferable that the upper end surface of the crack-inducing joint body is inclined so as to descend toward the flat surface side.

The crack-inducing waterproof structure for a concrete structure according to the present invention includes a formwork for placing the concrete structure, the crack-inducing joint fixed inside the formwork, and the crack-inducing joint fixed to the formwork. The crack-inducing joint is formed by a joint fixing screw that is detachable from the opening on the flat surface side of the screwing groove of the crack-inducing joint, and after forming the concrete structure, the mold and the joint fixing screw are removed, and the crack The induction joint is obtained by leaving the joint joint in the concrete structure so as to be exposed on the outer surface of the concrete structure.

The method for inducing crack-inducing waterproofing of a concrete structure according to the present invention includes a step of fixing the crack-inducing joint to the formwork with the joint fixing screw before placing the concrete, and the formwork and the joint after placing the concrete. Removing the fixing screw and leaving the crack-inducing joint in the concrete structure so as to be exposed on the outer surface of the concrete structure; And a step of injecting a repair agent into an opening groove provided in the crack-inducing joint and filling the crack with the repair agent.

  In the crack-inducing joint of the present invention, since the screwing groove communicates with the upper and lower ends of the crack-inducing joint, the joint fixing screw can be inserted into the screwing groove at any position on the screwing groove. And the formwork can be fixed easily and quickly. In particular, even when there is an obstacle such as a steel pipe for fixing the mold around the screw hole, the crack-inducing joint can be easily fixed to the mold by shifting the screw up and down. In addition, since the crack-inducing joint of the present invention is left in the concrete structure, a cross-sectional defect portion does not occur, a sealing agent and a mortar for refilling the cross-sectional defect portion are not required, and work labor can be reduced. Cost of sealing agent can be reduced. In addition, the crack-inducing joint of the present invention has a tapered portion in its arbitrary cross-sectional shape, and has an opening groove at the tip of the tapered portion, so that cracks are reliably generated in a presumed location inside the concrete structure. Can be made. Furthermore, by injecting a repairing agent into the opening groove, the repairing agent can be filled in the cracks to be waterproofed, water can be reliably prevented from entering the concrete structure, and the strength of the concrete structure can be reduced. The period can be prevented.

  The joint fixing screw of the present invention can be easily inserted into the screwing groove from the opening of the screwing groove of the crack-inducing joint, and the side surface of the screw head is screwed into the screwing groove only by rotating the joint fixing screw to the right. It can be easily and quickly fixed to any location on the screwing groove, and since it does not rotate rightward, it can prevent co-rotation. Can be fixed easily and quickly.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view of the first embodiment of the crack-inducing joint of the present invention, and FIG. 2a is a cross-sectional view of the crack-inducing joint of the first embodiment of the present invention. Is a cross-sectional view of the second embodiment of the crack-inducing joint of the present invention, FIG. 2c is a cross-sectional view of the third embodiment of the crack-inducing joint of the present invention, and FIG. FIG. 4a is a cross-sectional view of a crack-inducing joint according to a fourth embodiment of the present invention, and FIG. 4a shows a fifth embodiment of the crack-inducing joint of the present invention, in a state where it is disposed in a concrete structure. FIG. 4b is a schematic perspective view showing the upper end surface, and FIG. 4b is a cross-sectional view of FIG. 4a.

  FIG. 5a is a front view of the joint fixing screw of the present invention, FIG. 5b is a view showing the joint fixing screw of the present invention as viewed from the screw tip, and FIG. 6a is a joint fixing screw of the present invention. FIG. 6B is a second explanatory view showing a fixing method of the joint fixing screw of the present invention to the joint, and FIG. 6C is a joint fixing screw of the present invention. It is 3rd explanatory drawing which shows the fixing method to the joint.

  FIG. 7 is a schematic cross-sectional view showing one embodiment of the crack-induced waterproof structure of the present invention, and FIG. 8 is a schematic cross-sectional view showing another embodiment of the crack-induced waterproof structure of the present invention.

(Crack-induced joint)
The crack induction joint 1 of this invention is demonstrated based on 1st Embodiment according to FIGS. The crack-inducing joint 1 of the present invention includes a long crack-inducing joint main body 2 and a coating layer 3 of an adhesive material that covers the crack-inducing joint main body 2.

  As shown in FIG. 1, the crack-inducing joint body 2 is a long member. The material of the crack-inducing joint body 2 is not particularly limited as long as it has a strength that does not break or bend when fixed to the mold 41 or when placing concrete, but has a certain strength and can be processed. It is preferably an easy metal such as iron, copper or aluminum, a synthetic resin such as polyvinyl chloride, or an engineering resin such as polyacetal resin or nylon. The length of the crack-inducing joint body 2 is adjusted according to the size of the concrete structure 20. When the length is insufficient, the crack-inducing joint body 2 can be extended by connecting it in the longitudinal direction, so the length is not particularly limited. Although the manufacturing method of the crack induction joint main body 2 is not specifically limited, Manufacture by the cheap and easy extrusion process is preferable.

  As shown in FIG. 2a, the crack-inducing joint body 2 has a flat portion 10 in its arbitrary cross-sectional shape. As shown in FIG. 1, the flat portion 10 is a flat surface 10 in the long member. The flat surface 10 of the crack-inducing joint body 2 and the flat surface inside the mold 41 are fixed in close contact with each other without a gap. This prevents uncured concrete from flowing between the crack-inducing joint 1 and the mold 41.

  Although the width of the flat surface 10 is not particularly limited, it is preferably 15 to 30 mm, more preferably 20 to 27 mm, and most preferably 23 in consideration of providing the screwing groove 12 in the crack-inducing joint 1. ~ 25 mm.

  The flat surface 10 is provided with a screwing groove 12 which is open on the flat surface 10 side and has a T-shaped arbitrary cross-sectional shape whose inner width L1 is wider than the opening width L2. The depth L1 is the length L1 in FIG. 2a, and the opening width L2 is the length L2 in FIG. 2a. A shelf generated by the difference between the depth L1 and the opening width L2 serves as a seating surface of the screw head 31 of the joint fixing screw 30 inserted into the screwing groove 12.

  The lengths of the back width L1 and the opening width L2 are relative, and the difference between the back width L1 and the opening width L2 is that the seating surface of the screw head 31 of the joint fixing screw 30 is sufficiently secured. The difference is preferably 4 mm or more, and in order to firmly fix the crack-inducing joint 1 to the mold 41, the difference is more preferably 8 mm or more. The depth of the screwing groove 12 is preferably 8 to 20 mm in consideration of the size of the crack-inducing joint 1, the size of the corresponding joint fixing screw 30, and the required tightening strength. Preferably it is 10-15 mm, Most preferably, it is 11-13 mm.

  Since the screwing groove 12 communicates with the upper and lower end surfaces of the crack-inducing joint body 2, the joint fixing screw 30 can be inserted into the screwing groove 12 at an arbitrary position on the screwing groove 12. The degree of freedom of the location where the screw 30 is fixed is high. Thereby, the crack induction joint 1 can be fixed to the formwork 41 easily and quickly. In particular, in the prior art, when a screw hole is provided in the crack-inducing joint 1 and the mold 41 to fix them, there is an inconvenience that the steel pipe or the like that fixes the mold 41 becomes an obstacle and closes the screw hole. Sometimes. In such a case, screw holes must be provided in both the crack-inducing joint 1 and the formwork 41 again at the above-described locations where there is no inconvenience, which is a great disadvantage in terms of work. In the case of the screwing groove 12 of the present invention, even if such inconvenience occurs, the screw fixing location can be freely shifted up and down on the screwing groove 12, so that the inconvenience can be easily avoided. can do. For the same reason, it can be easily and quickly removed. Furthermore, since the screwing groove 12 communicates with the upper and lower end surfaces of the crack-inducing joint body 2, it is suitable for extrusion processing of the crack-inducing joint body 2 and facilitates its manufacture.

  As shown in FIG. 2a, the crack-inducing joint body 2 is formed with a tapered portion 11 that tapers toward the opposite side of the flat portion 10 in an arbitrary cross-sectional shape. The tapered portion 11 has a tapered shape as it goes to the opposite side of the flat portion 10, so that when the crack-inducing joint 1 is disposed in the concrete structure 20, the tip of the tapered portion 11 is moved. A crack 43 can be generated inside the concrete structure 20 as a starting point.

  As shown in FIG. 2a, in the first embodiment of the present invention, the adhesive area with the coating layer 3 can be widened, and the taper shape is slightly curved while it is easy to manufacture. Is formed. By widening the adhesion area with the coating layer 3, the adhesive strength of the coating layer 3 is sufficiently exerted, and a gap is formed between the concrete and the coating layer 3 and between the coating layer 3 and the crack-inducing joint body 2. Is suppressed.

  Since the length from the flat surface 10 of the crack induction joint 1 to the front-end | tip of the taper part 11 is determined according to the magnitude | size of the concrete structure 20, it is not specifically limited. Usually, if the cross-sectional defect width formed by a crack inducing member or joint is 30% or more of the total width of the concrete structure 20, the crack 43 can be preferentially generated at a corresponding portion of the concrete structure 20. . In order to surely generate the crack 43 at a place assumed in advance, it is preferable that the length is long. However, if the length is too long, it will be an obstacle to the reinforcing bar 46 disposed inside the mold 41, so the crack-inducing joint 1. The length from the flat surface 10 to the tip of the tapered portion 11 is preferably 30 to 100 mm, more preferably 40 to 80 mm, and most preferably 45 to 70 mm.

  As shown in FIGS. 1 and 2 a, in the first embodiment, a column 13 along the longitudinal direction of the crack inducing joint body 2 is integrally formed at the tip of the tapered portion 11 of the inducing joint body 2. Thereby, it is easy to form the connecting holes 18 at the upper and lower ends of the cylinder 13, and a plurality of crack-inducing joints 1 can be connected in the longitudinal direction. Further, by inserting a hollow pipe or the like into the connection hole 18, the repair agent can be injected from the pipe and the repair agent can be filled into the crack 43 through the opening groove 14 connected to the connection hole 18. As a result, the crack 43 inside the concrete structure 20 can be sealed, and the waterproofing of the concrete structure 20 can be maintained for a long time.

  The diameter of the column 13 is not particularly limited because it is determined according to the size of the concrete structure 20, but considering that the diameter of the connecting hole 18 is about 6 mm, it is preferably 8 to 16 mm, more preferably. Is 10 to 14 mm, and most preferably 11 to 13 mm.

  An opening groove 14 that communicates the upper end surface and the lower end surface of the crack-inducing joint body 2 is provided at the tip of the tapered portion 11. The opening groove 14 ensures the generation of the crack 43 from the tip. Moreover, since the opening groove | channel 14 connects the upper end surface and lower end surface of the crack induction joint main body 2, manufacture by extrusion is made easy.

  Although the width of the opening groove 14 is not particularly limited, it is preferably 0.5 to 5 mm, more preferably considering that the crack 43 is reliably generated inside the concrete structure 20 and the repair agent is injected. It is 1-4 mm, Most preferably, it is 2-3 mm. For the same reason, the depth of the opening groove 14 is not particularly limited, but is preferably 4 to 10 mm, more preferably 5 to 9 mm, and most preferably 6 to 8 mm.

  The opening groove 14 is covered with a sheet 15 in which the opening of the opening groove 14 does not transmit uncured concrete. The sheet 15 prevents uncured concrete from entering the opening groove 14 when the concrete is placed. However, since the repairing agent injected into the opening groove 14 can be permeated, the repairing agent is injected from the opening groove 14 after placing the concrete, and the repairing agent is filled in the crack 43 generated in the concrete structure 20. The crack 43 can be sealed and waterproofed. The material of the sheet 15 is not particularly limited as long as it does not permeate uncured concrete but can permeate liquid. However, paper, nonwoven fabric, woven fabric, and mesh sheet having predetermined permeability are preferable, and are inexpensive and easy to handle. Easy paper is more preferred.

  As shown in FIG. 2b, in the second embodiment of the present invention, at least one protrusion 16 having a height of 1 to 12 mm is provided on the surface of the crack-inducing joint 1 in contact with the concrete. In FIG. 2 b, protrusions 16 extending in parallel with the flat surface 10 are formed on both side surfaces of the tapered portion 11 of the crack inducing joint 1. Thereby, the water stop effect of the crack induction joint 1 can be improved. It is preferable that the protrusions 16 are formed at the upper and lower ends of the crack-inducing joint body 2 consistently from the reason that the water stop effect can be improved and the extrusion process is excellent.

  Although the height of the protrusion 16 is not particularly limited, it is preferably 1 to 12 mm, more preferably 5 to 10 mm, and most preferably 7 to 8 mm in consideration of the water stop effect and ease of manufacture. For the same reason, the width of the protruding portion 16 is not particularly limited, but is preferably 1 to 5 mm, more preferably 2 to 4 mm, and most preferably 3 mm.

  As shown in FIG. 2 c, in the third embodiment of the present invention, the crack-inducing joint 1 does not integrally form the column 13 at the tip of the tapered portion 11, because it is easy to manufacture. The part 11 is formed with a straight line.

  As shown in FIG. 3, in the fourth embodiment of the present invention, protrusions 17 are respectively formed on the left and right ends of the flat surface 10 of the crack inducing joint 1. Thus, when the crack-inducing joint 1 is fastened to the mold 41 with the joint fixing screw 30, the tightening pressure is concentrated on the protrusions 17, and uncured concrete is prevented from entering the flat surface 10 with certainty. After hardening, the appearance of the flat surface 10 of the crack-inducing joint 1 that appears on the outer surface of the concrete structure 20 when the formwork 41 is removed is made excellent. Even if the uncured concrete flows into the flat surface 10 beyond the covering layer 3 and the protruding portion 17, the boundary between the hardened concrete and the flat surface 10 is clear because the protruding portion 17 separates the hardened concrete. Therefore, the concrete hardened on the flat surface 10 can be easily removed with a spatula or the like. Further, in order to prevent a gap generated between the crack-inducing joint 1 and the concrete structure 20 from appearing on the outer surface due to shrinkage at the time of hardening of the concrete, the protrusions 17 are slightly in the lateral width direction of the crack-inducing member 1. It is preferable to form it in a spread.

  Although the width and height of the protrusion 17 are not particularly limited, the width is preferably 0.1 to 5 mm, more preferably 0.3 to 3 mm, taking into account the ease of processing and the appearance after the mold 41 is removed. The height is most preferably 0.5 to 2 mm, and the height is preferably 0.1 to 1 mm, more preferably 0.2 to 0.8 mm, and most preferably 0.4 to 0.6 mm.

  The upper outer surface of the concrete structure 20 is formed with a surface such as a flat surface or a slope according to its use. The crack-inducing joint 1 may appear on the upper outer surface of the concrete, or may be embedded without appearing on the outer surface. However, in order to inject a repair agent, the connecting hole connected to the opening groove 14 or the opening groove. It is preferable that 18 appears on the concrete upper outer surface.

  As shown in FIG. 4a, in the fifth embodiment of the present invention, the crack inducing joint 1 is formed obliquely so that its upper end surface descends toward the flat surface 10 side. Thereby, the crack induction joint 1 can be arrange | positioned without inconvenience also with respect to the chamfering formed in the corner | angular of the upper part of the concrete structure 20. FIG. Further, in this case, the upper end of the column 13 portion is not obliquely inclined and is flat like the upper surface of the concrete structure 20. Thereby, a pipe can be installed in the connecting hole 18 provided at the upper end of the cylinder 13, a repair agent can be injected from the pipe, and the repair agent can be filled into the crack 43 generated in the concrete through the opening groove 14. The upper end surface of the crack inducing joint 1 is formed by cutting. Further, as shown in FIG. 4b, after the upper end surface is inclined, the appearance can be made excellent by covering it with a concrete layer 21.

  In the crack-inducing joint 1, surfaces other than the upper end surface, the lower end surface, the flat surface 10, and the opening groove 14 of the crack-inducing joint body 2 are covered with the coating layer 3 made of an adhesive material. The adhesive material is for preventing a gap from being generated between the concrete and the covering layer 3 and between the covering layer 3 and the crack-inducing joint body 2, thereby allowing water to enter the crack 43 from the outside of the concrete structure 20. Can be prevented. Further, when the repair agent is filled into the crack 43 from the opening groove 14, the coating layer 3 prevents the repair agent from leaking out of the concrete structure 20. The adhesive material is not particularly limited as long as it has adhesiveness, but butyl rubber having excellent adhesion to concrete is particularly preferable.

(Fixing screw)
The joint fixing screw 30 of the present invention will be described with reference to FIGS. 5 and 6. As shown in FIGS. 5a and 5b, the joint fixing screw 30 according to the present invention has a length L3 of the long side of the screw head 31 that is the same as the depth L1 of the screwing groove 12 of the crack-inducing joint 1 or the depth L1. Slightly longer. As a result, when the joint fixing screw 30 is inserted into the screw fixing groove 12 of the crack inducing joint 1 and tightened and rotated, the side surface of the screw head 31 comes into contact with the inner width L1 of the screw fixing groove 12 and is fixed. Co-rotation of the screw 30 is prevented, and the crack inducing joint 1 is easily and quickly fixed to the mold frame 41.

  The short side length L4 of the screw head 31 is shorter than the opening width L2 of the screwing groove 12 of the crack inducing joint 1. Thereby, the joint fixing screw 30 can be easily inserted into an arbitrary portion of the screwing groove 12 of the crack inducing joint 1. Moreover, the removal can be performed easily and rapidly for the same reason.

  As shown in FIG. 5b, when viewed from the screw tip 32 side, the shape of the screw head 31 is such that a horizontally-long rectangular lower right corner and upper left corner are formed in an arc shape R, and the outer periphery of the screw head 31 is the upper right corner thereof. The distance L5 between the corner and the lower left corner is formed to be the longest. Thus, when the joint fixing screw 30 is inserted into the screwing groove 12 of the crack-inducing joint 1 and tightened and rotated, the side surface of the screw head 31 has a screwing groove 12 at the lower right corner and upper left corner of the arc R. In the vicinity of the upper right corner and the lower left corner of the screw head 31, the inner width L1 of the screwing groove 12 is contacted and fixed. As a result, co-rotation is prevented when the joint fixing screw 30 is tightened with the nut 42, and the crack-inducing joint 1 is easily and quickly fixed to the mold 41. The joint fixing screw 30 is not particularly limited as long as it has a certain strength capable of withstanding the tightening of the screw, but is made of a metal such as iron, copper, or aluminum, a synthetic resin such as polyvinyl chloride, a polyacetal resin, nylon, or the like It is preferable that it is made of engineering resin.

  Next, the relationship between the joint fixing screw 30 of the present invention and the screwing groove 12 will be described. As shown in FIG. 6 a, the joint fixing screw 30 has the short side length L 4 of the screw head 31 shorter than the opening width L 2 of the screwing groove 12 of the crack inducing joint 1. Can be inserted into the screwing groove 12 from the flat surface 10 side.

  Since the screw is tightened clockwise as viewed from the screw tip 32, the inserted joint fixing screw 30 is rotated to the right. The length L3 of the long side of the screw head 31 is equal to or slightly longer than the depth L1 of the screwing groove 12 of the crack inducing joint 1, but the lower right corner and the upper left corner of the screw head 31 are arcuate. Since it is formed in R, the distance between the lower right corner and the upper left corner is shorter than the depth L1 of the screwing groove 12. Thereby, the side surface of the screw head 31 does not contact the depth L1 of the screwing groove 12 in the vicinity of the lower right corner and the upper left corner.

  When the rotation is further continued, the upper right corner and the lower left corner of the screw head 31 approach the depth L1 of the screwing groove 12. As shown in FIG. 6b, the side surface of the screw head 31 is in contact with the depth L1 where the outer circumferential width of the screw head 31 is equal to the length of the depth L1 of the screwing groove 12. Thereby, the screw head 31 is fixed to the screwing groove 12. Since the length L3 of the long side of the screw head 31 is suppressed to be the same as or slightly longer than the depth L1 of the screwing groove 12 of the crack-inducing joint 1, a sufficient area of the seating surface of the screw head 31 is secured. This is preferable.

  The length L3 of the long side of the screw head 31 is preferably 0 to 20% longer than the length of the back width L1, more preferably 0 to 10% longer than the length of the back width L1, and most preferably the long side of the screw head 31. The length L3 and the depth L1 of the screwing groove 12 of the crack-inducing joint 1 are the same length.

  As shown in FIG. 6c, when the length L3 of the long side of the screw head 31 and the depth L1 of the screwing groove 12 of the crack-inducing joint 1 are the same, the screw head 31 is connected to the joint fixing screw 30. Is inserted into the screwing groove 12 and rotated approximately 90 degrees to the right, the upper right corner and the lower left corner are in contact with and fixed to the inner width L1. Thereby, a seat surface can be made into the maximum area and the joint fixing screw 30 can fully be fastened.

  Next, the co-rotation preventing mechanism for the joint fixing screw 30 according to the present invention will be described. As described above, the joint fixing screw 30 fixed to the crack inducing joint 1 is in a state in which the screw tip 32 protrudes from the crack inducing joint 1. The screw tip 32 is passed through a screw hole provided in the mold 41 and the joint fixing screw 30 is tightened from the outside of the mold 41 with a nut 42 to fix the crack inducing joint 1 to the mold 41.

  Since the joint fixing screw 30 is fixed by contact between the side surface of the screw head 31 and the depth L1 of the screwing groove 12 of the crack inducing joint 1, the joint fixing screw 30 does not rotate further and does not rotate together. Further, since the lower right corner and the upper left corner of the screw head 31 are formed in an arcuate shape R, a contact portion between the side surface of the screw head 31 and the screwing groove 12 becomes a contact surface. Thereby, compared with the case where the lower right corner and the upper left corner of the screw head 31 are corners, the contact area between the side surface of the screw head 31 and the screwing groove 12 is increased, and both are fixed more firmly. . Thereby, even when removing the joint fixing screw 30 after placing the concrete, it is possible to prevent co-rotation, and it is possible to easily and quickly install and remove the crack-inducing joint 1 from the mold 41.

(Crack-induced waterproof structure and method for concrete structures)
A crack-inducing waterproof structure 40 and method using the crack-inducing joint 1 and joint fixing screw 30 according to the present invention will be described with reference to FIGS.

  As shown in FIG. 7, in one embodiment of the crack-inducing waterproof structure 40 of the present invention, the mold 41 covering the four sides of the concrete structure 20 and the flat surface 10 are fixed in close contact with the mold 41. The crack induction joint 1 and the joint fixing screw 30 which fixes the formwork 41 and the crack induction joint 1 are provided. With this configuration, the flat surfaces of the crack inducing joint 1 face the mold 41 and can be easily and quickly fixed by the fastening force of the joint fixing screw 30. Further, a tapered portion 11 is provided on the opposite side of the flat surface 10 of the crack inducing joint 1, and the tip of the tapered portion 11 faces the center of the concrete structure 20. As a result, a crack 43 is generated in the concrete structure 20 starting from the tip of the tapered portion 11. The shape of the mold 41 is a flat plate, and the material is not particularly limited, but an inexpensive and lightweight wood plate or resin plate is used.

  Next, the installation method of the crack induction waterproofing structure 40 of this invention is demonstrated. The concrete structure 20 is formed by placing uncured concrete in a mold 41 that surrounds the concrete structure 20.

  The crack-inducing joint 1 is fixed to the inside of the mold 41, that is, the side on which the concrete is placed, by joint fixing screws 30 before the concrete is placed. The mold 41 is provided with a plurality of screw holes for fixing the crack inducing joint 1. The joint fixing screw 30 is inserted into the screwing groove 12 so that the short side L4 of the screw head 31 is along the opening width L2 of the screwing groove 12 of the crack inducing joint 1. Since the screwing groove 12 is formed so as to communicate with the upper and lower ends of the crack-inducing joint 1, the screwing groove 12 can be freely inserted and fixed at an arbitrary position in the vertical direction. Thereby, the operation | work which passes the screw tip 32 through a screw hole becomes unnecessary, and it can make an operation | work easy and quick.

  The long side L3 of the screw head 31 of the joint fixing screw 30 is the same as or slightly longer than the depth L1 of the screwing groove 12, and the lower right corner and the upper left corner of the screw head 31 are formed in an arcuate shape R. Therefore, when the right side is rotated to tighten the joint fixing screw 30, the side surface of the screw head 31 does not come into contact with the depth L1 of the screwing groove 12 in the vicinity of the lower right corner and the upper left corner. At locations where the outer peripheral width is equal to the length of the back width L1 of the screwing groove 12, the side surface of the screw head 31 contacts and is fixed to the back width L1. Thereby, since the joint fixing screw 30 does not rotate further to the right, it is possible to prevent co-rotation of the screw and to easily and quickly install and remove the crack-inducing joint 1 from the mold 41.

  When uncured concrete is placed in the mold 41 and the concrete is cured, the crack-inducing waterproof structure 40 of the concrete structure 20 is formed, and the mold 41 and the joint fixing screw 30 are removed. However, the crack-inducing joint 1 is left in the concrete structure 20 such that the flat portion 10 facing the mold 41 is exposed on the outer surface of the concrete structure 20. This eliminates the need for a sealing agent or mortar that backfills the cross-sectional defects generated on the concrete outer surface, and eliminates the removal work and the backfilling work of the sealing agent and mortar, compared to the type that removes joints. be able to. In addition, costs such as sealing agents and mortar can be reduced.

  In the crack-inducing waterproof structure 40 of the present invention, the crack-inducing joint 1 has the tapered portion 11, so that the cross-sectional defect width of the concrete structure 20 becomes large at that location, and the tip of the tapered portion 11 is caused by the shrinkage stress accompanying the hardening of the concrete. As a starting point, the crack 43 can be generated inside the concrete structure 20. Since the opening portion 14 is provided in the tapered portion 11, the crack 43 can be generated more reliably. As shown in FIG. 7, the crack inducing joint 1 is disposed in the concrete structure 20 so that the tip of the tapered portion 11 faces the concrete structure 20. Thereby, the crack 43 can be reliably generated between the both end portions having a large cross-sectional defect width inside the concrete structure 20.

  The generated crack 43 is filled with the repair agent by injecting the repair agent into the opening groove 14 provided in the crack inducing joint 1. Thereby, the crack 43 is sealed and waterproofed, the waterproof function of the concrete structure 20 is strengthened, and the strength reduction can be prevented for a long time.

  The repair agent may be an inorganic repair agent or an organic repair agent as long as it has good fluidity and excellent repair effect, and is not particularly limited, but it is preferable to use a highly permeable colloidal silica aqueous dispersion. preferable. The aqueous colloidal silica dispersion is ultrafine particles of silica, so that it penetrates into the cracks 43 generated in the concrete structure 20 and reacts with the alkali substances and hydrates in the concrete around the cracks 43 to gel. The inside of the crack 43 can be filled with this silica gel and repaired. In addition, urethane repair agents and cement milk can also be used. However, it is necessary that the steel does not contain or generate an acid or chlorine that easily corrodes the reinforcing bar.

  As shown in FIG. 8, another embodiment of the crack induction preventing structure 40 of the present invention shows the crack induction waterproof structure 40 when the concrete structure 20 is thick. Since the internal crack inducing member 44 is disposed inside the reinforcing bar 46 inside the concrete structure 20 by the clamp 45, the cross-sectional defect width at the location is increased, and the crack 43 is reliably generated at the location assumed in advance. Can do.

It is a schematic perspective view in 1st Embodiment of the crack induction joint of this invention. (A) is a cross-sectional view in the first embodiment of the crack-inducing joint of the present invention, (b) is a cross-sectional view in the second embodiment of the crack-inducing joint of the present invention, (c) is FIG. 5 is a transverse sectional view of a third embodiment of a crack-inducing joint of the present invention. It is a transverse cross section in a 4th embodiment of a crack induction joint of the present invention. (A) shows 5th Embodiment of the crack induction joint of this invention, the schematic perspective view which shows the upper end surface in the state arrange | positioned in the concrete structure, (b) is sectional drawing of FIG. 4a. is there. (A) is a front view of the joint fixing screw of the present invention, and (b) is a diagram showing a state of the joint fixing screw of the present invention as viewed from the screw tip. (A) is 1st explanatory drawing which shows the fixing method to the joint of the joint fixing screw of this invention, (b) is 2nd explanatory drawing which shows the fixing method to the joint of the joint fixing screw of this invention, (c) ) Is a third explanatory view showing a method of fixing the joint fixing screw of the present invention to the joint. It is a schematic cross-sectional view which shows one embodiment of the crack induction waterproofing structure of this invention. It is a schematic cross-sectional view showing another embodiment of the crack-inducing waterproof structure of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crack induction joint 2 Crack induction joint body 3 Coating layer 10 Flat part (flat surface)
DESCRIPTION OF SYMBOLS 11 Tapered part 12 Screwing groove 13 Cylinder 14 Opening groove 15 Sheet 16 Protrusion part 17 Protrusion part 18 Connection hole 20 Concrete structure 21 Concrete layer 30 Joint fixing screw 31 Screw head 32 Screw tip 40 Crack induction waterproof structure 41 Form frame 42 Nut 43 Crack 44 Internal crack inducing member 45 Clamp 46 Reinforcing bar L1 Width of screwing groove 12 L2 Opening width of screwing groove 12 L3 Length of long side of screw head 31 L4 Length of short side of screw head 31 L5 Screw head 31 Distance between upper right corner and lower left corner

Claims (7)

A long crack-inducing joint body, which is attached to a formwork for placing concrete and is left in the concrete structure so as to be exposed on the outer surface of the concrete structure after placing the concrete, and the crack-inducing joint A crack-inducing joint comprising a coating layer of an adhesive material covering the main body,
The crack-induced joint body, and facing said mold, made from any cross-sectional shape thereof, a flat portion, a tapered portion that tapers as going to the opposite side of the flat portion,
A flat surface formed of the flat portion is provided with a screw groove that opens to the flat surface side and has a T-shaped cross section whose inner width is wider than the opening width.
From the opening on the flat surface side of the screwing groove, a joint fixing screw can be attached to and detached from the screwing groove,
At the tip of the tapered portion, an opening groove that communicates the upper end surface and the lower end surface of the crack-inducing joint body is provided,
The opening of the opening groove is covered with a sheet that does not penetrate uncured concrete,
The crack induction joint which the said coating layer covers surfaces other than the upper end surface of the said crack induction joint main body, a lower end surface, the said flat surface, and the said opening groove | channel. The crack-inducing joint according to claim 1, wherein protrusions having a width of 0.1 to 5 mm and a height of 0.1 to 1 mm are provided on the left and right ends of the flat surface. The crack-inducing joint according to claim 1 or 2, wherein at least one protrusion having a height of 1 to 12 mm is provided on a surface of the crack-inducing joint in contact with the concrete. The crack induction joint of Claim 1, 2, or 3 which integrally forms the cylinder which follows the longitudinal direction of the said crack induction joint main body at the front-end | tip of the said taper part. The crack inducing joint according to claim 1, 2, 3 or 4, wherein an upper end surface of the crack inducing joint main body is obliquely disposed so as to descend toward the flat surface side. A formwork for placing a concrete structure, a crack-inducing joint according to claim 1, which is fixed inside the formwork, and the crack-inducing joint is fixed to the formwork. , Formed by a joint fixing screw that is detachable from the opening on the flat surface side of the screwing groove of the crack-inducing joint ,
A concrete structure obtained by forming the concrete structure, removing the mold and the joint fixing screws, and leaving the crack-inducing joint in the concrete structure so as to be exposed on the outer surface of the concrete structure. Body crack-induced waterproof structure. The concrete設前by eye locations fixing screw, and fixing the crack-induced joint according to claim 1, 2, 3, 4 or 5, wherein said mold,
Removing the mold and the joint fixing screw after placing the concrete, and leaving the crack-inducing joint in the concrete structure so as to be exposed on the outer surface of the concrete structure;
A step of generating a crack starting from a tip of a tapered portion of the crack-inducing joint inside the concrete structure by the crack-inducing joint;
Injecting a repair agent into an opening groove provided in the crack-inducing joint, and filling the crack with the repair agent.

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