JP2008184736A - Construction method for crack inducing joint structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method for a crack inducing joint structure capable of preventing occurrence of positional deviation of a member buried into the inside of concrete to increase rate of deficiency of cross section from a joint bar for forming crack inducing joint, increasing rate of concentration of crack into the crack inducing joint, and preventing foreign matter from being left in the inside of the concrete member since the member buried into the inside of concrete to increase rate of deficiency of cross section can be inserted into a form from an upper part after the construction work by use of form is completed, thereby improving construction property. <P>SOLUTION: A flexible tube 1 is arranged in the inside of the form along the joint bars 5a, 5b for forming crack inducing joint provided on an inner face of the form and is filled with pressure fluid a to place concrete C while holding a linear shape of the flexible tube. After the concrete is hardened to some extent, the flexible tube is pulled out and removed to form a cavity 8 being parallel with the crack inducing joint 9 in the inside of the concrete member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for constructing a crack-induced joint structure that increases the concentration rate of cracks on the crack-induced joint.

  For example, in a concrete member such as a concrete wall, the temperature stress accompanying heat generation after the concrete is placed and cracks due to drying shrinkage are generated at a predetermined position to maintain the aesthetics of the surface, and at random other than the predetermined position. In order to prevent the intrusion of rainwater or the like due to cracks, a crack-inducing joint is provided on the surface of the concrete member, while an angle material is embedded in the concrete member in parallel with the crack-inducing joint, or Patent Document 1 ~ 4 etc., as seen in vinyl chloride pipes, vinyl chloride or iron pipes with a non-vulcanized butyl rubber sealing material layer on the outer peripheral surface, hollow mortar pipes, vinyl chloride filled with non-shrink mortar Concentration of cracks on crack-induced joints by burying pipes etc. and increasing the cross-sectional defect rate Devised to enhance the have been made.

  However, in all of the conventional techniques, the members for increasing the cross-sectional defect rate embedded in the concrete are rigid rod-shaped members such as angle members and pipes that cannot be bent. Stops, formwork separators, upper floor beam bars, floor formwork, etc. become obstructed and cannot be inserted into the formwork, and must be set from the lateral direction during wall reinforcement.

  For this reason, not only is the workability complicated due to the bar arrangement work, but the rod-shaped member is set before the joint rod for forming the crack-induced joint is applied to the predetermined position on the inner surface of the formwork. There is a case where the positional relationship between the crack and the joint rod for forming a crack-inducing joint that is attached to a predetermined position on the inner surface of the mold is distorted, and an operation for correcting the positional relationship is generated. In addition, when the correction is insufficient, there is a problem that the crack concentration rate on the crack-induced joint is not necessarily increased.

  Moreover, it is not preferable for ensuring the quality of concrete that foreign matters such as vinyl chloride pipes remain inside the concrete member. In the case of angle materials, they are made of steel, so there is no problem in ensuring the quality of the concrete, but structural design considerations are required by inserting angle materials, so do not leave them inside the concrete. Never passed.

Japanese Utility Model Publication No.59-128813 JP-A-63-51546 JP-A-9-184205 Japanese Patent No. 3775185

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to insert a member for increasing the cross-sectional defect ratio embedded in the concrete into the formwork from the top after completion of the formwork. Therefore, it is possible to prevent misalignment between the member for increasing the cross-sectional defect ratio embedded in the concrete and the joint rod for forming the crack-induced joint, and to increase the concentration ratio of the crack to the joint that induces the crack. Another object of the present invention is to provide a construction method for a crack-induced joint structure with good workability so that no foreign matter remains inside the concrete member.

  The technical means taken by the present invention in order to achieve the above object are as follows. That is, in the construction method of the crack-inducing joint structure according to the first aspect of the invention, a flexible tube is installed inside the mold along the joint rod for forming the crack-inducing joint provided on the inner surface of the mold. And when filling the inside of the flexible tube with pressure fluid, the concrete is placed inside the mold with the flexible tube kept in a straight shape, and the concrete is hardened to some extent. Then, the flexible tube is removed, and a cavity parallel to the crack-inducing joint is formed inside the concrete member.

  Invention of Claim 2 is the construction method of the crack induction joint structure of Claim 1, Comprising: The lower end of a flexible tube is inserted in the cavity formed in the wall concrete of a lower floor, It is characterized by the above-mentioned. It is said.

  Invention of Claim 3 is a construction method of the crack induction joint structure of Claim 1 or 2, Comprising: By filling the inside of a flexible tube with a pressure fluid, the said flexible tube is a circumference | surroundings. The flexible tube is made to stand on its own by abutting against the wall of the wall, or at least the side surface of the flexible tube on the lower side in the direction of the concrete flow is brought into contact with the accessory muscle fixed to the wall. It is characterized by having become independent.

  Invention of Claim 4 is the construction method of the crack induction joint structure in any one of Claims 1-3, Comprising: The inside of a cavity is filled with a hardening material, It is characterized by the above-mentioned.

  Invention of Claim 5 is the construction method of the crack induction joint structure in any one of Claims 1-3, Comprising: It fills the inside of a cavity with a water stop material, It is characterized by the above-mentioned.

  According to the first aspect of the present invention, as the member for increasing the cross-sectional defect rate embedded in the concrete, a flexible tube that is linearly retained by filling the inside with a pressure fluid is used. After completion of the formwork, it can be inserted into the formwork from above. In other words, the flexible tube can be bent in a state where it is not filled with the pressure fluid. Therefore, even if the upper-level beam line or the floor formwork is present above the formwork, It is possible to fold it into an arbitrary shape and insert its lower end side between the wall bars in the mold, and to avoid these obstacles by filling with pressure fluid after inserting it to the appropriate depth .

  Therefore, after completion of the mold work, a member (flexible tube) for increasing the cross-sectional defect rate is inserted while visually confirming the position of the crack-inducing joint-forming joint rod attached to a predetermined position on the inner surface of the mold. Because it is easy to construct so that the positional relationship between the cross-sectional defect rate increasing member and the crack-inducing joint forming joint rod does not change, the cross-sectional defect rate increasing member and the crack-inducing joint Misalignment with the forming joint rod can be prevented, and the concentration rate of cracks on the crack-induced joint can be increased.

  Moreover, when the concrete is hardened to some extent, the shape of the flexible tube is broken by removing the pressure fluid filled inside, so that it can be easily removed from the concrete member and removed. There is no need to leave foreign matter inside the member. In addition, if a flexible tube made of a material (for example, polylactic acid fiber) that dissolves with the alkali component of concrete is used, the flexible tube is removed by dissolution, and concrete The step of extracting from the member can be omitted.

According to the invention described in claim 2, since the lower end of the flexible tube is inserted into the cavity formed in the wall concrete of the lower floor, the positions of the upper and lower floor cavities (cross-sectional defect increasing portions) are shifted. There is no fear, and it is possible to increase the concentration rate of cracks on the crack-induced joints in the multi-level wall concrete.

  According to the invention described in claim 3, the flexible tube can be made to stand independently by abutting at least the side surface of the flexible tube on the lower side in the concrete flow direction with the accessory muscle fixed to the wall reinforcement. Although it is possible, in particular, when a flexible fluid is filled in the inside of the flexible tube so that the flexible tube abuts on the surrounding wall muscle and becomes independent, the wall The work to fix the flexible tube positioning supplementary bar (supplementary bar that prevents the flexible tube from moving in the lateral direction due to the flow of concrete) at a predetermined position will be omitted. very good.

  In the first to third aspects of the invention, the cavity may be left as it is, but as in the fourth aspect of the invention, the inside of the cavity may be filled with a hardener, As in the invention described in (1), a water-stopping material may be filled inside the cavity.

  According to the fourth aspect of the present invention, it is possible to increase the concentration rate of cracks on the crack-induced joints by increasing the cross-sectional defect rate while increasing the compressive strength of the concrete member by the hardening material filled in the cavity. . As the hardener, in addition to mortar or concrete, for example, grout, epoxy resin, resin mortar, cement milk, or a combination thereof can be selected as appropriate.

  In particular, when the concrete placed inside the mold is hardened to some extent, the flexible tube is removed to form a cavity parallel to the crack-inducing joint inside the concrete member. When filling the inside of mortar or concrete, the concrete around the cavity that was constructed in advance and the mortar or concrete that was constructed in the interior of the cavity later are different in the timing of placement and hardening, Skin separation occurs on the joint surface, and the cross section is lost even after the upper frame is constructed. Therefore, while increasing the compressive strength of the concrete member by mortar or concrete filled in the cavity, the concentration rate of cracks on the crack-induced joint can be increased by increasing the cross-sectional defect rate.

  In addition, as mortar or concrete with which the inside of a cavity is filled, the same intensity | strength as the concrete cast | injected in a mold may be sufficient, and different intensity | strength may be sufficient. In addition, even if it is the same strength as concrete placed in the mold (mortar or concrete having the same drying shrinkage rate), due to different timing of placement and hardening, skin separation occurs on the joint surface, As mortar or concrete to be filled in the cavity, when using low strength (mortar or concrete with a high drying shrinkage rate) than the concrete placed in the mold, it shrinks more than the concrete member. Even if the time of placing is close to each other, skin separation is surely generated on the joining surface. Therefore, there is an advantage in that the degree of freedom in terms of the process of forming the cavity by removing the flexible tube and the process of filling the interior of the cavity with mortar or concrete is great.

  According to the invention described in claim 5, since the water-stopping material is filled in the cavity, the water-stopping material applied to the crack-inducing joint deteriorates, and rainwater enters from the cracks concentrated on the crack-inducing joint. Even if it does, further penetration can be prevented by the water stop material filled in the cavity. As the waterstop material, resin mortar, asphalt, bentonite powder, elastic body such as urethane rubber and silicone rubber, rubber asphalt, and the like can be appropriately selected in addition to urethane.

  Filling the cavity with the water-stopping material may be performed following the formation of the cavity by removing the flexible tube, and should be performed when water leakage occurs or there is a risk of water leakage after the building is completed. May be.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2, reference numeral 1 denotes a flexible tube as a member for increasing a cross-sectional defect rate used to form a cavity parallel to a crack-inducing joint formed on the surface of a concrete wall. is there. An inlet 1a with an on-off valve V is provided at the upper end of the flexible tube 1, and a pressure fluid pumped from a pressure fluid supply source (not shown) (air is used in the illustrated embodiment, but water is used). It may be a liquid such as, etc.) By filling a, the shape is maintained in a straight line (hollow rod shape), but in a state where the pressure fluid a is removed, it can be bent, that is, it is in a guñaguna state. ing.

  The material of the flexible tube 1 may be one that elastically expands and contracts like rubber, but does not elastically expand and contract like a cloth or a resin film, but is as soft as a rubber tube. It may have. In any case, it is desirable to make the flexible tube 1 less likely to adhere to concrete by making the material of the flexible tube 1 difficult to adhere to concrete or providing a release agent layer on the surface.

  Next, an example of the construction method of the crack induction joint structure using said flexible tube 1 is demonstrated. First, as shown in FIG. 3, after the rebar formwork is completed, the flexible tube 1 not filled with the pressure fluid a is inserted into the molds 2a and 2b from above. At that time, even if an obstacle such as an upper-level beam line or a floor formwork exists above the molds 2a and 2b, the flexible tube 1 can be bent in a state where the pressure fluid a is not filled. Therefore, as shown in FIG. 1, it is possible to bend the flexible tube 1 into an arbitrary shape and insert the lower end side between the double-barreled wall bars 3 in the molds 2a and 2b. . And after inserting to the desired depth (for example, after inserting the lower end of the flexible tube 1 into the cavity 8 formed inside the wall concrete of the lower floor as shown in FIGS. 1 and 2) As shown in FIG. 4, these obstacles can be avoided by filling the pressure fluid a. In FIG. 1, 4 indicates a flexible hose for placing concrete, and an arrow X indicates the flow direction of the concrete C placed in the mold.

  As shown in FIG. 3 and FIG. 4, crack-inducing joint forming joint rods 5a and 5b are already attached at predetermined positions on the inner surfaces of the inner and outer molds 2a and 2b when the mold is assembled. While confirming the positions of the joint rods 5a and 5b by visual observation, the flexible tube 1 can be installed by accurately following the positions.

  Thereafter, as shown in FIG. 5, concrete C is placed inside the molds 2a and 2b. Since the flexible tube 1 is formed in a straight shape (hollow bar shape) by filling the inside with the pressure fluid a, the side surface on the lower side in the flow direction of the concrete C is fixed to the wall reinforcement 3. , The flexible tube 1 is pressed against the splicing bar 6 by the concrete C and becomes independent.

  Therefore, for example, as shown in FIG. 1, a simple fixing means that simply binds the upper end side of the flexible tube 1 with a string, a wire, or the like to a bridge 7 laid horizontally on the upper end of the formwork or fixes it with an adhesive tape. Can be adopted.

In particular, in this embodiment, as shown in FIGS. 1 and 2, the lower end of the flexible tube 1 is inserted into the cavity 8 formed in the wall concrete of the lower floor. In addition to preventing unexpected movement of the lower end side of the flexible tube 1 and improving the self-supporting property of the flexible tube 1 and improving the parallelism between the crack-inducing joint and the cavity, the cavity 8 can be left without a lid. The concrete C can be prevented from flowing into the cavity 8 in the lower floor. In addition, since the cavity 8 is not formed in the lowest floor, it is an unexpected thing on the lower end side of the flexible tube 1 by the flow prevention member (for example, angle) fixed on the splicing bar 6 or the floor concrete. Or a recess is formed at a predetermined position of the bottom floor concrete, and the lower end of the flexible tube 1 is inserted into this.

  When the concrete C in the molds 2a and 2b has hardened to some extent (for example, one week after placing the concrete), the flexible tube 1 is removed and parallel to the crack-inducing joint inside the concrete wall. A cavity 8 is formed. In extracting the flexible tube 1, the open / close valve V of the inlet 1 a is opened and the air inside is extracted, so that the flexible tube 1 is deflated as shown in FIG. Since it returns to a free state, even if an obstacle exists above the mold, the flexible tube 1 can be pulled out and removed.

  Thereafter, the molds 2a and 2b are disassembled and removed, and as shown in FIG. 7, a water-stopping material 10 and its backup material 11 are applied to the crack-inducing joint 9.

  According to this structure, the cavity 8 parallel to the crack induction joint 9 formed on the concrete wall surface is formed inside the concrete wall, and the cross-sectional defect rate of the concrete at the position of the crack induction joint 9 is increased. Therefore, the crack concentration rate on the crack-induced joint 9 can be increased, and the crack b can be generated at the position of the crack-induced joint 9. Further, since the flexible tube 1 is removed and the cavity 8 is formed, it is not necessary to leave a foreign substance inside the concrete wall.

  The intrusion of rainwater by the crack b is prevented by the water-stopping material 10 applied to the crack-inducing joint 9 on the concrete wall surface side, so the cavity 8 may be left as it is, When the outer waterproofing material 10 deteriorates and needs repair after the building is completed, for example, as shown in FIG. 8, after removing the indoor waterproofing material 10 and the backup material 11, A necessary number of lateral holes 12 reaching the cavity 8 are drilled at the bottom of the crack-inducing joint 9 by using a drill or the like, and a water-stopping material c such as urethane is injected from the lateral hole 12 into the cavity 8 and filled. it can.

  In the illustrated embodiment, after completion of the building, the concrete wall is perforated and the water-stopping material c is injected. However, following the step of extracting the flexible tube 1 shown in FIG. The water-stopping material c may be injected into the cavity 8. As the waterstop material, resin mortar, asphalt, bentonite powder, elastic body such as urethane rubber and silicone rubber, rubber asphalt, and the like can be appropriately selected in addition to urethane.

  Although not shown, following the extraction process of the flexible tube 1 shown in FIG. 6, a hardener (for example, mortar, concrete, grout, epoxy resin, resin mortar, cement milk, Or, a combination of these may be used. In the case of such a crack-induced joint structure, the concentration rate of cracks on the crack-induced joint 9 is increased by increasing the cross-sectional defect rate while increasing the compressive strength of the concrete wall by the hardener filled in the cavity 8. be able to.

In particular, when mortar or concrete is used as the hardener, the timing of placing and hardening differs between the concrete around the cavity 8 that was previously constructed and the mortar or concrete that was subsequently constructed inside the cavity 8. As a result, skin separation occurs on the joint surface, and a cross-sectional defect occurs even after the upper housing is constructed. Therefore, while increasing the compressive strength of the concrete wall with mortar or concrete filled in the cavity, the crack concentration ratio on the crack-induced joint 9 can be increased by increasing the cross-sectional defect rate. The mortar or concrete filled in the cavity 8 may have the same strength as the concrete placed in the molds 2a and 2b or may have a different strength. Moreover, even if it is the same strength (mortar or concrete having the same drying shrinkage rate) as the concrete placed in the molds 2a and 2b, the joining surface is separated by different timings for placing and curing. However, when using mortar or concrete filling the inside of the cavity 8 with a lower strength (mortar or concrete having a higher drying shrinkage rate) than the concrete placed in the molds 2a and 2b, it is compared with a concrete wall. Therefore, even when the placement times are close to each other, skin separation is surely generated on the joint surface, and the formation process of the cavity 8 by removing the flexible tube 1 and the cavity 8 are performed. There is a great degree of freedom in the process of filling mortar or concrete into the interior.

  9 to 11 show another embodiment of the present invention. When the flexible tube 1 is filled with the pressure fluid a, the flexible tube 1 comes into contact with the surrounding wall muscle 3. It is characterized by being made independent.

  The concrete construction procedure of the construction method of the crack induction joint structure in this embodiment is as follows. First, as shown in FIG. 9A, the reinforcement of the wall bars 3 and the assembly work of the molds 2a and 2b are performed.

  Thereafter, as shown in FIG. 9B, the flexible tube 1 not filled with the pressure fluid is inserted into the molds 2a and 2b from above. At that time, the flexible tube 1 can be bent in a state where pressure fluid is not filled even when obstacles such as upper-level beam streaks and floor formwork exist above the formwork 2a and 2b. From FIG. 1, it is possible to bend the flexible tube 1 into an arbitrary shape and insert the lower end of the flexible tube 1 between the double-placed wall bars 3 in the molds 2a and 2b. Avoid these obstacles.

  Further, since the flexible tube 1 is inserted after the completion of the mold work, the crack-inducing joint forming joint bars 5a and 5b are already attached to the predetermined positions on the inner surfaces of the inner and outer molds 2a and 2b when the mold is assembled. It has been. Accordingly, it is possible to install the flexible tube 1 while accurately confirming the positions of the joint rods 5a and 5b on both sides while visually confirming the positions.

  After the insertion to the desired depth, as shown in FIG. 9C, the flexible tube 1 is filled with the pressure fluid a, so that the flexible tube 1 is kept in a straight shape (hollow bar shape). At the same time as it is formed, it comes into contact with the surrounding wall muscle 3 and becomes independent. Therefore, the positioning supplementary bar 6 for the flexible tube 1 and the fixing bar 7 in the above-described embodiment are unnecessary, and the positioning supplementary bar for the flexible tube 1 is fixed in advance to a predetermined position of the wall bar. The work of placing, the work of attaching the pier to the upper end of the formwork, and the work of fixing the upper end side of the flexible tube 1 to the pier are omitted, and the workability is very good.

  In this state, as shown in FIG. 10A, concrete C is placed inside the molds 2a and 2b. Then, when the concrete C in the molds 2a and 2b is hardened to some extent (for example, one week after placing the concrete), as shown in FIG. As shown in FIG. 10C, a cavity 8 parallel to the crack-inducing joint 9 is formed inside the concrete wall. In extracting the flexible tube 1, the open / close valve V of the inlet 2 is opened and the air inside is extracted, so that the flexible tube 1 is deflated as shown in FIG. Since the original bendable state is restored, the flexible tube 1 can be pulled out and removed even if an obstacle exists above the mold.

  Thereafter, as shown in FIG. 11A from above the cavity 8, mortar or concrete M is filled in the cavity 8 as an example of the hardened material, and the concrete C exhibits a predetermined strength. The frames 2a and 2b are disassembled and removed, and as shown in FIG. 11B, the water-stopping material 10 and its backup material 11 are applied to the crack-inducing joint 9.

According to this configuration, the concrete C around the cavity 8 constructed in advance and the mortar or concrete M constructed in the cavity 8 later have different timings for placing and hardening, so that the joint surface Skin separation occurs, and the cross section is lost even after the upper housing is constructed.

  Therefore, while increasing the compressive strength of the concrete wall by the mortar or concrete M filled in the cavity, it is possible to increase the concentration rate of cracks on the crack-induced joint 9 by increasing the cross-sectional defect rate. The mortar or concrete M filled in the cavity 8 may have the same strength as the concrete C placed in the molds 2a and 2b, or may have a different strength. In addition, even if the strength is the same as the concrete C to be placed in the molds 2a and 2b (mortar or concrete having the same drying shrinkage rate), due to different timings for placing and curing, the skin is divided into the joint surfaces. However, when a mortar or concrete M filled in the cavity 8 is used with a lower strength (mortar or concrete having a higher drying shrinkage rate) than the concrete C placed in the molds 2a and 2b, a concrete wall is used. Since the shrinkage is more than that in the case, even if the time of placing is close to each other, skin separation is surely generated on the joining surface, and the step of forming the cavity 8 by removing the flexible tube 1 In addition, the degree of freedom in the filling process of the mortar or concrete into the cavity 8 is great. Other configurations and operations are the same as those of the embodiment of FIGS.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, For example, it replaces with the hardening | curing material (mortar or concrete M) shown to (A) of FIG. Implemented in various modes within a range not departing from the gist of the present invention, such as filling the cavity 8 with urethane, resin mortar, asphalt, bentonite powder, elastic body such as urethane rubber and silicone rubber, and water-stopping material such as rubber asphalt. Of course you can.

It is a schematic longitudinal front view explaining the construction method of the crack induction joint structure which concerns on this invention. FIG. 2 is a schematic longitudinal sectional front view following the step of FIG. 1. It is a cross-sectional top view of the principal part which shows the construction method of a crack induction joint structure. FIG. 4 is a transverse plan view of a main part following the step of FIG. 3. FIG. 5 is a cross-sectional plan view of a main part following the process of FIG. 4. FIG. 6 is a cross-sectional plan view of a main part following the process of FIG. 5. FIG. 7 is a cross-sectional plan view of a main part following the process of FIG. 6. It is a cross-sectional top view of the wall concrete which shows other embodiment of this invention. It is a cross-sectional top view of the principal part which shows other embodiment of this invention. FIG. 10 is a transverse plan view of the main part following the process of FIG. 9. It is a cross-sectional plan view of the principal part following the process of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible tube 1a Inlet 2a, 2b Formwork 3 Wall reinforcement 4 Flexible hose 5a, 5b Joint rod for crack induction joint formation 6 Attached reinforcement 7 Pier 8 Cavity 9 Crack induction joint 10 Water stop material 11 Backup material 12 Side hole C Concrete M Mortar or Concrete V On-off valve X Arrow a Pressure fluid b Cracking c Water stop material

Claims (5)

  By installing the flexible tube along the joint rod for forming the crack-inducing joint provided on the inner surface of the mold inside the mold, and filling the flexible tube with the pressure fluid, With the flexible tube kept in a straight shape, concrete is placed inside the mold, and when the concrete has hardened to some extent, the flexible tube is removed to induce cracks in the concrete member. A method of constructing a crack-induced joint structure characterized by forming a cavity parallel to the joint.   The method for constructing a crack-inducing joint structure according to claim 1, wherein the lower end of the flexible tube is inserted into a cavity formed in the wall concrete of the lower floor.   By filling the inside of the flexible tube with pressure fluid, the flexible tube abuts on the surrounding wall muscles so as to be self-supporting, or at least on the lower side of the flexible tube in the concrete flow direction. The method for constructing a crack-inducing joint structure according to claim 1 or 2, wherein the flexible tube is made to stand by contacting a side surface with a supplementary bar fixed to a wall bar.   The construction method for a crack-inducing joint structure according to any one of claims 1 to 3, wherein the inside of the cavity is filled with a hardener.   The construction method for a crack-induced joint structure according to any one of claims 1 to 3, wherein a water-stopping material is filled in the cavity.

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