Mold form to be buried and production method of mold form to be buried

Abstract

To provide mold forms to be buried allowing stable fixation on each other and suppressing intrusion of concrete paste and rain water into a gap between the mold forms to be buried.SOLUTION: A mold form assembly body (2), for a mold forms (10) to be buried, comprises moisture hardened type adhesive (9) on an adhesive surface where mold forms (1) to be buried adhere to each other, and on an outer surface of the mold form assembly body (2) air tight material (4) is arranged in a joint part (3) between the mold forms (1) to be buried.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an embedded formwork and a method for manufacturing the embedded formwork.

Background Art

[0002] In conventional concrete structures, it is known to provide a hollow portion inside the concrete structure to achieve weight reduction. Examples of concrete structures suitable for such weight reduction include caissons forming the foundation of breakwaters, pontoon bridges, and bridge piers supporting structures constructed at high locations such as elevated bridges.

[0003] A concrete structure having a hollow portion is generally constructed by installing an inner formwork for forming the hollow portion inside an outer formwork that forms the outer shape of the structure, and placing concrete in the space between the outer formwork and the inner formwork.

[0004] In recent years, a construction method has been developed in which a plurality of buried formwork members made of expanded polystyrene are used as the buried formwork, aiming to shorten the construction period and reduce the number of personnel by omitting the work related to the installation and removal of the inner formwork and shoring. This construction method is disclosed in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in this construction method, the fixation between the embedded formwork members becomes unstable. Also, when constructing a reinforced concrete structure, concrete paste and rainwater may penetrate into the gaps between the embedded formwork members. When placing concrete, buoyancy is generated on the lightweight expanded polystyrene embedded formwork members, and uneven loads are generated on the concrete placement pressure, causing the embedded formwork to shift from its predetermined position. Such problems may occur.

[0007] One aspect of the present invention aims to realize an embedded formwork and a method for manufacturing the embedded formwork that can stably fix the embedded formwork members to each other and prevent concrete paste and rainwater from easily penetrating into the gaps between the embedded formwork members.

Means for Solving the Problems

[0008] To solve the above problems, one aspect of the present invention is as follows.

[0009] 〔1〕An embedded formwork for forming a hollow part inside a reinforced concrete structure, comprising a formwork assembly having a plurality of embedded formwork members made of a polystyrene-based resin foam, and an airtight waterproof material. The formwork assembly is configured such that the embedded formwork members are adhered in the horizontal and vertical directions, and a moisture-curing type adhesive is provided on the adhesion surface between the embedded formwork members. On the outer surface of the formwork assembly, the airtight waterproof material is provided at the joint part between the embedded formwork members.

[0010] 〔2〕The embedded formwork according to 〔1〕, wherein the moisture-curing type adhesive contains a modified silicone-based resin adhesive.

[0011] 〔3〕The embedded formwork according to 〔2〕, wherein the modified silicone-based resin adhesive has a viscosity of 50 Pa·s to 900 Pa·s at 23°C.

[0012] 〔4〕The embedded formwork according to any one of 〔1〕 to 〔4〕, wherein the airtight waterproof material includes a base material layer and an adhesive layer, the adhesive layer has an acrylic-based resin adhesive layer or a butyl rubber-based adhesive layer, and the thickness of the adhesive layer is 50 μm to 300 μm.

[0013] 〔5〕The color of the base material layer is any one selected from the group consisting of yellow, green, red, and light blue, and the embedded formwork of 〔4〕.

[0014] 〔6〕The formwork assembly includes a fastening fitting for fastening the embedded formwork members together. The fastening fitting is arranged across at least two adjacent embedded formwork members in the horizontal direction and has a protrusion portion embedded and fixed to these embedded formwork members. The embedded formwork according to any one of 〔1〕 to 〔5〕.

[0015] 〔7〕A plurality of anchors are erected in the foundation of the reinforced concrete structure. The formwork assembly has a through hole through which the anchor penetrates. The embedded formwork according to any one of 〔1〕 to 〔6〕.

[0016] 〔8〕A formwork assembly having a plurality of embedded formwork members made of a polystyrene-based resin foam, and an airtight waterproof material. A method for manufacturing an embedded formwork for forming a hollow portion inside a reinforced concrete structure, including a coating step of applying a moisture-curing adhesive to the bonding surface between the embedded formwork members, an adhesion step of bringing the bonding surfaces into contact with each other to bond the embedded formwork members together in the horizontal and vertical directions to manufacture a formwork assembly, and an airtight waterproof material installation step of providing the airtight waterproof material at the joint portion between the embedded formwork members on the outer surface of the formwork assembly. A method for manufacturing an embedded formwork.

Advantages of the Invention

[0017] According to one aspect of the present invention, the embedded formwork members can be stably fixed to each other, and it is difficult for concrete paste or rainwater to penetrate into the gap between the embedded formwork members.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described in detail. In the following, the case where it is an embedded formwork applied to a bridge will be described. Needless to say, the embedded formwork according to the present embodiment is not limited to a bridge and can be applied to any reinforced concrete structure. Further, the present invention is not limited to this, and various modifications are possible within the described range, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments and examples are also included in the technical scope of the present invention. In addition, unless otherwise specified in this specification, "A~B" representing a numerical range means "A or more (including A and greater than A), B or less (including B and less than B)".

[0020] In addition, in the drawings of this application, "LD" represents the length direction, "LDa" represents one side in the length direction, "LDb" represents the other side in the length direction, "WD" represents the width direction, "WDa" represents one side in the width direction, "WDb" represents the other side in the width direction, "HD" represents the vertical direction, "HDa" represents the upper side which is one side in the vertical direction, and "HDb" represents the lower side which is the other side in the vertical direction. Here, the "length direction" refers to one of the horizontal directions and is the depth direction of the bridge, and the "width direction" means the direction orthogonal to the length direction in the horizontal direction. Also, the "vertical direction" is the direction perpendicular to both the "length direction" and the "width direction". It should be noted that the HD direction can be said to be the direction in which the embedded formwork members are stacked in the formwork assembly.

[0021] FIG. 1 is a sectional view in the length direction showing an example of the schematic configuration of a reinforced concrete structure B provided with an embedded formwork 10 according to this embodiment. FIG. 2 is a sectional view taken along the line A-A of the concrete structure B shown in FIG. 1.

[0022] As shown in FIGS. 1 and 2, the reinforced concrete structure B includes a foundation B1, a peripheral wall portion B2, and an embedded formwork 10. The foundation B1 is installed on the ground. Also, the peripheral wall portion B2 is installed on the foundation B1. Reinforcing bars are embedded in the foundation B1 and the peripheral wall portion B2. The structure of the reinforcing bars embedded in the foundation B1 and the peripheral wall portion B2 can adopt a structure known in the construction technology of reinforced concrete structures.

[0023] The embedded formwork 10 also serves as an inner formwork and is embedded inside the peripheral wall portion B2. The embedded formwork 10 forms a hollow portion inside the reinforced concrete structure B. Also, the embedded formwork 10 includes a formwork assembly 2 having a plurality of embedded formwork members 1. The embedded formwork member 1 is a rectangular parallelepiped member made of a polystyrene-based resin foam. The formwork assembly 2 has a configuration in which a plurality of embedded formwork members 1 are adhered in the horizontal direction and the vertical direction. More specifically, a plurality of embedded formwork members 1, 1... are arranged side by side in the WD direction and the LD direction with respect to each other and are stacked in the HD direction.

[0024] In addition, a plurality of fixing reinforcing bars 6 (anchors) are erected on the foundation B1 of the reinforced concrete structure B. The fixing reinforcing bar 6 has its end on the LDb side fixed to the foundation B1 and penetrates the formwork assembly 2 in the HD direction. The fixing reinforcing bar 6 protrudes from the surface on the HDa side of the formwork assembly 2. Therefore, the formwork assembly 2 has a through hole 7 through which the fixing reinforcing bar 6 penetrates. The fixing reinforcing bar 6 has a function of locking the movement of the formwork assembly 2 in the LD direction and the WD direction inside the peripheral wall portion B2. Further, such a configuration is effective when the place for assembling the embedded formwork 10 is prepared separately from the foundation B1 in the manufacturing method (construction method) of the embedded formwork 10. In such a method, for example, after separately assembling the embedded formwork 10 at the assembling place, the embedded formwork 10 is transferred to the foundation B1. In this method, when transferring to the foundation B1, the position of the through hole 7 is aligned with the position of the fixing reinforcing bar 6, and the embedded formwork 10 can be installed on the foundation B1 while being guided by the fixing reinforcing bar 6. Therefore, the alignment of the embedded formwork 10 on the foundation B1 becomes easy.

[0025] Further, a frame member 5 is disposed on the uppermost surface on the HDa side of the formwork assembly 2. The frame member 5 is fixed to the fixing reinforcing bar 6. The frame member 5 functions as a lid member that locks the movement of the formwork assembly 2 in the HD direction.

[0026] FIG. 3 is a perspective view showing a schematic configuration of the formwork assembly 2 provided in the embedded formwork 10 according to the present embodiment. Further, FIG. 4 is a perspective view showing a schematic configuration of the embedded formwork 10 according to the present embodiment.

[0027] As shown in FIG. 3, on the outer surface of the formwork assembly 2, a joint portion 3 is formed between the embedded formwork members 1. On the outer surface of the formwork assembly 2, the joint portion 3 forms a joint between the embedded formwork members 1. A gap may be formed in the joint portion 3 between the embedded formwork members 1 by the embedded formwork members 1.

[0028] Here, in the embedded formwork 10, the formwork assembly 2 has a moisture-curing adhesive on the bonding surface between the embedded formwork members 1. Since the embedded formwork 10 is large, the assembly of the formwork assembly 2 is basically an outdoor operation. Therefore, the bonding strength between the embedded formwork members 1 is affected by weather conditions such as rain, temperature, and humidity. Here, when a moisture-curing adhesive is used for bonding between the embedded formwork members 1 as in the embedded formwork 10 according to the present embodiment, even if there is some moisture such as rainwater on the bonding surface of the embedded formwork member 1, the moisture promotes the curing reaction of the moisture-curing adhesive, so that stable adhesiveness can be ensured.

[0029] As an adhesive used for bonding between the embedded formwork members 1, there is a solvent-evaporation type adhesive. In the solvent-evaporation type adhesive, the solvent contained in the adhesive evaporates to promote adhesive curing. When a solvent-evaporation type adhesive is used for bonding between the embedded formwork members 1, if the temperature is extremely low, evaporation may not proceed, and it may take time for the adhesive to cure. For this reason, when a solvent-evaporation type adhesive is used, there is a concern that the construction and working efficiency of the embedded formwork 10 may decrease.

[0030] Also, as an adhesive used for bonding between the embedded formwork members 1, there is a hardener-curing type adhesive. In the hardener-curing type adhesive, two or more hardeners are mixed with the adhesive main agent at the work site, and adhesive curing proceeds by a chemical reaction. When a hardener-curing type adhesive is used for bonding between the embedded formwork members 1, the handling of the adhesive is complicated, and after mixing the hardener and the adhesive main agent, it is necessary to quickly apply and bond it to the adherend. For this reason, when a hardener-curing type adhesive is used, if it takes time for the handling work of the adhesive, there is a concern that curing will proceed and stable adhesiveness cannot be maintained.

[0031] As described above, according to the embedded formwork 10, since a moisture-curing adhesive is used for bonding between the embedded formwork members 1, the embedded formwork members 1 can be stably fixed to each other.

[0032] Further, as shown in FIG. 4, the embedded formwork 10 includes a formwork assembly 2 and an airtight waterproof material 4. The airtight waterproof material 4 is provided at the joint portion 3 between the embedded formwork members 1 on the outer surface of the formwork assembly 2, particularly on the side wall surface. This makes it difficult for cement paste (slurry) or rainwater to enter the gap between the embedded formwork members 1. As a result, the airtight waterproof material 4 has the effect of making it difficult for cement paste or rainwater to penetrate into the inside of the formwork assembly 2. As shown in FIG. 4, the airtight waterproof material 4 is provided on the outer surfaces in the WD direction (both side surfaces on the WDa side and the WDb side) and the outer surfaces in the LD direction (both side surfaces on the LDa side and the LDb side) of the formwork assembly 2. Further, the airtight waterproof material 4 covers at least the region of the joint portion 3.

[0033] When the airtight waterproof material 4 is not provided, that is, when the joint portion 3 is exposed to the outside, when constructing the reinforced concrete structure B, cement paste (slurry) or rainwater that constitutes the peripheral wall portion B2 enters (flows in) from the gap between the embedded formwork members 1. And thereby, buoyancy is generated in the formwork assembly 2, and it tends to be difficult to stably install the embedded formwork 10 at the determined installation location.

[0034] In the configuration shown in FIG. 4, the airtight waterproof material 4 is provided on the outer surfaces in the WD direction and the outer surfaces in the LD direction. However, the installation position of the airtight waterproof material 4 on the outer surface of the formwork assembly 2 only needs to achieve the above effect and is not limited to the installation position of the airtight waterproof material 4 shown in FIG. 4. The outer surfaces on the HDa side (upper surface) and / or the HDb side (bottom surface) of the airtight waterproof material 4 may be covered, and it can be appropriately set according to the construction environment of the reinforced concrete structure B. In the construction of the reinforced concrete structure B, there is a tendency for cement paste (slurry) or rainwater to enter the formwork assembly 2 from the horizontal directions (WD direction and LD direction). Therefore, it is preferable that the airtight waterproof material 4 is provided at least on the horizontal outer surfaces of the formwork assembly 2, and more preferably, it is provided on the outer surface on the HDa side in addition to the outer surface.

[0035] The configuration of the airtight waterproof material 4 is not particularly limited as long as the above effects are achieved. FIG. 5 is a perspective view schematically showing an example of the configuration of the airtight waterproof material 4. FIG. 6 is a perspective view showing the schematic configuration of the airtight waterproof material 4 in a tape-wound form.

[0036] As shown in FIG. 5, the airtight waterproof material 4 includes a release agent layer 4a, an adhesive layer 4b, and a base material layer 4c. In the airtight waterproof material 4, the release agent layer 4a, the adhesive layer 4b, and the base material layer 4c are laminated in this order. Further, the airtight waterproof material 4 preferably has a tape-wound form as shown in FIG. 6. The tape-wound form is a form in which the tape-shaped airtight waterproof material 4 is wound around a core material. Since the airtight waterproof material 4 is in such a form, when assembling the embedded formwork 10, the covering operation of the airtight waterproof material 4 for each joint portion 3 becomes easy.

[0037] The release agent layer 4a is a layer that covers the adhesive layer 4b and has a function of maintaining the adhesiveness of the adhesive layer 4b until the actual use of the airtight waterproof material 4. Therefore, in a state where the airtight waterproof material 4 is provided at the joint portion 3, the release agent layer 4a of the airtight waterproof material 4 is peeled off from the adhesive layer 4b, and the airtight waterproof material 4 essentially includes the adhesive layer 4b and the base material layer 4c.

[0038] In the airtight waterproof material 4, the adhesive layer 4b is a layer that contacts the joint portion 3 between the embedded formwork members 1. In actual use of the airtight waterproof material 4, after removing the release agent layer 4a, the adhesive layer 4b preferably has an acrylic resin adhesive layer or a butyl rubber adhesive layer. When the adhesive layer 4b has an acrylic resin adhesive layer, although the adhesive layer 4b tends to be difficult to adhere in a low-temperature environment, it can be preferably used because the risk of deterioration due to heat or ultraviolet rays is small. Also, when the adhesive layer 4b has a butyl rubber adhesive layer, since the adhesive layer 4b has relatively high flexibility, it can follow the rough surface such as the uneven shape on the surface of the embedded formwork member 1 and maintain stable adhesiveness. However, there is a concern that the adhesive layer 4b may deteriorate if the embedded formwork 10 is exposed to light or heat. However, for the following reasons, the risk of deterioration of the adhesive layer 4b is extremely small. That is, the target site where the embedded formwork 10 is arranged is the hollow portion of the reinforced concrete structure B, so there is little possibility that light or heat directly acts on the embedded formwork 10.

[0039] And the thickness of the adhesive layer 4b is preferably 50 μm to 300 μm, and more preferably 75 μm to 200 μm. When the thickness of the adhesive layer 4b is less than 50 μm, since the adhesive layer 4b is thin relative to the size of the gap (joint portion 3) between the embedded formwork members 1, the followability of the adhesive layer 4b to the gap is low, and the covering of the joint portion 3 of the airtight waterproof material 4 tends to be insufficient. On the other hand, when the thickness of the adhesive layer 4b exceeds 300 μm, the followability of the adhesive layer 4b to the rough surface such as the surface uneven shape of the embedded formwork member 1 tends to decrease, and as a result, it tends to allow the intrusion of rainwater or the like from the gap between the rough surface and the adhesive layer 4b.

[0040] In addition, in the airtight waterproof material 4, the base material layer 4c is arranged on the side opposite to the joint portion 3 with respect to the adhesive layer 4b. In the airtight waterproof material 4, the base material layer 4c is visible from the outside of the embedded formwork 10. The color of the base material layer 4c is preferably any one selected from the group consisting of yellow, green, red, and light blue. By using the base material layer 4c composed of these colors, it becomes easy to distinguish from the embedded formwork member 1 which is white or gray, and the covering degree of the airtight waterproof material 4 at the joint portion 3 tends to be easily distinguishable. Further, when performing the assembly work of the embedded formwork 10 in the hollow portion of a reinforced concrete structure B such as a bridge, since it is constructed in an environment with relatively low illuminance (not exposed to light), by using the base material layer 4c composed of these colors, the visibility of the airtight waterproof material 4 can be ensured, and stable airtightness at the joint portion 3 by the airtight waterproof material 4 can be ensured.

[0041] In addition, in the embedded formwork 10, the formwork assembly 2 may be provided with a fastening fitting for fastening the embedded formwork members 1 together. FIG. 7 is a perspective view showing a schematic configuration of the fastening fitting 8 provided in the formwork assembly 2. FIG. 8 is a perspective view schematically showing a state in which the fastening fitting 8 is installed on the formwork assembly 2.

[0042] As shown in FIG. 7, the fastening fitting 8 has a rectangular plate-shaped main body 8a, and protrusions 8b and 8c. The protrusions 8b and 8c are embedded and fixed to the embedded formwork member 1. The protrusions 8b and 8c extend in the HD direction from the side portions of the rectangular shape of the main body 8a. Also, the protruding directions of the protrusions 8b and 8c are opposite to each other. That is, the protrusion 8b protrudes toward the HDa side with respect to the main body 8a, while the protrusion 8c protrudes toward the HDb side with respect to the main body 8a. Further, on the side portions of the rectangular shape of the main body 8a, the protrusions 8b and 8c are formed alternately.

[0043] Also, as shown in FIG. 8, the fastening fitting 8 is arranged to straddle at least two horizontally adjacent embedded formwork members 1. Specifically, the fastening fitting 8 is arranged to straddle three adjacent embedded formwork members 1a to 1c in the WD direction and the LD direction. The rectangular side portions of the main body of the fastening fitting 8 are arranged so as to cross the boundaries between the embedded formwork members 1a and 1b, the boundaries between the embedded formwork members 1b and 1c, and the boundaries between the embedded formwork members 1a and 1c. In the arrangement of the fastening fitting 8 shown in FIG. 8, the protrusions are embedded and fixed not only to the embedded formwork members 1a to 1c but also to the embedded formwork members laminated on the embedded formwork members 1a to 1c.

[0044] When bonding the embedded formwork members 1 to each other with a moisture-curing adhesive during the assembly of the embedded formwork 10, by installing the fastening fitting 8, it is possible to position the embedded formwork members 1 relative to each other until the moisture-curing adhesive cures, and prevent displacement between the embedded formwork members 1 during construction. And since the positioning between the embedded formwork members 1 becomes accurate, the outer surface of the formwork assembly 2 becomes relatively flat at the joint portion 3. Therefore, the coating of the airtight waterproof material 4 on the joint portion 3 can be stably constructed, and the intrusion of rainwater or the like from the joint portion 3 can be further suppressed.

[0045] In the formwork assembly 2, it is preferable that two or more fastening fittings 8 are installed for one embedded formwork member 1. Thereby, the formwork assembly 2 can be made stable.

[0046] Also, the fastening fitting 8 is not limited to the configuration shown in FIG. 7, and it may have protrusions embedded and fixed to at least two horizontally adjacent embedded formwork members 1. For example, referring to FIG. 7 for explanation, as a modified example, the fastening fitting 8 may have a configuration having only the protrusions 8b or 8c on the rectangular side portions of the main body 8a. The fastening fitting 8 as a modified example is used when bonding the embedded formwork members 1 arranged on the outermost HDa side in the formwork assembly 2.

[0047] Figure 9 is a perspective view showing the schematic configuration of the frame member 5. As shown in Figure 9, the frame member 5 is disposed on the surface of the embedded formwork 10 on the HDa side. The frame member 5 has a rectangular frame shape along the periphery of the surface of the embedded formwork 10 on the HDa side. And the frame member 5 is fixed to the fixing reinforcing bars 6. Therefore, the movement of the embedded formwork 10 to the HDa side will be locked by the frame member 5. Thus, when constructing the reinforced concrete structure B, it is possible to prevent the embedded formwork 10 from floating up due to the concrete constituting the peripheral wall portion B2.

[0048] In addition, in the frame member 5 shown in Figure 9, for reinforcement, a linear bar is connected to the rectangular frame shape so as to straddle two opposing sides of the rectangular frame shape.

[0049] (Embedded formwork member) The embedded formwork material is made of a polystyrene-based resin foam. The shape of the embedded formwork member 1 can adopt a conventionally known shape applied to the embedded formwork, and generally it is a rectangular parallelepiped. Since the polystyrene-based resin foam has water repellency, is relatively lightweight, and has the required compressive strength, it is suitable as a material for the embedded formwork.

[0050] Examples of the polystyrene-based resin, which is the base resin of the polystyrene-based resin foam, include resins containing structural units derived from styrene-based monomers. Examples of the styrene-based monomer include styrene, methylstyrene, ethylstyrene, isopropylstyrene, dimethylstyrene, bromostyrene, chlorostyrene, vinyltoluene, vinylxylene, etc. Preferred examples of the resin having structural units derived from styrene-based monomers include a homopolymer of a styrene-based monomer obtained by polymerizing one kind of styrene-based monomer, or a copolymer of two or more styrene-based monomers obtained by polymerizing two or more styrene-based monomers. As the resin having structural units derived from styrene-based monomers, a polystyrene resin, which is a homopolymer of a styrene-based monomer and a copolymer of a styrene-based monomer, that is, a resin having only structural units derived from styrene-based monomers, can be preferably used.

[0051] In addition, as the foaming agent used for foaming the polystyrene resin foam, volatile hydrocarbon-based foaming agents such as propane, isobutane, butane, pentane, and hexane, inorganic gases such as air, nitrogen, and carbon dioxide, and water can be used. When using an inorganic gas, carbon dioxide is preferred because foamed particles with a relatively high foaming ratio are easily obtained. These foaming agents may be used alone or in combination of two or more.

[0052] In addition, the rectangular buried formwork member is preferably a bead foam molded body or an extrusion foam molded body. The molded body can be manufactured by a conventional bead method for foamed particle molding or a conventional extrusion foam molding method. And in this case, the bead foam molded body or the extrusion foam molded body preferably contains a polystyrene resin.

[0053] In addition, the density of the polystyrene resin foam is preferably 100 N / m 3 ~400 N / m 3 and more preferably 120 N / m 3 ~350 N / m 3 or less. When the density of the polystyrene resin foam is less than 100 N / m 3 , the allowable compressive stress described later cannot be exhibited, and the function as a formwork tends to be impaired. When the density of the polystyrene resin foam exceeds 400 N / m 3 , the weight of the rectangular buried formwork member increases, so the workability such as handleability tends to decrease. Note that the density of the above polystyrene resin foam adopts the unit in geotechnical engineering and is calculated by weight × gravitational acceleration.

[0054] In addition, the lower limit of the allowable compressive stress of the buried formwork member is preferably 10 kN / m 2 or more, more preferably 20 kN / m 2 or more, and even more preferably 50 kN / m 2 or more.

[0055] On the other hand, the upper limit of the allowable compressive stress of the buried formwork member is not particularly limited, but is preferably 400 kN / m 2The following is preferable, 200 kN / m 2 The following is more preferable. The allowable compressive stress can be measured according to the measurement method shown in JIS K-7220:2006. Specifically, a test piece with a longitudinal dimension of approximately 50 mm × a transverse dimension of approximately 50 mm × a thickness of approximately 50 mm is prepared, the test piece is compressed at a loading rate of 5 mm / min, and the compressive elastic modulus is calculated. The allowable compressive stress can be obtained as 1 / 100 of the calculated compressive elastic modulus.

[0056] Also, the embedded formwork member is preferably a block-shaped rectangular parallelepiped, and its size is not particularly limited, and various sizes of objects can be used according to the lamination method. The size of the embedded formwork member is generally about 1,000 mm in width × 2,000 mm in depth × 500 mm in height. By using such an embedded formwork member as the material of the embedded formwork, the entire embedded formwork can be lightened and it is easy to transport.

[0057] (Moisture-curing adhesive) The moisture-curing adhesive is not particularly limited, and conventionally known ones can be adopted. Examples of the moisture-curing adhesive include cyanoacrylate adhesives, urethane adhesives, silicone adhesives, and modified silicone resin adhesives. Among these, the moisture-curing adhesive preferably contains a modified silicone resin adhesive. The modified silicone resin adhesive has (a) appropriate heat resistance and water resistance, (b) small shrinkage after adhesion and curing, and (c) a curing time that is neither extremely short nor extremely long, so that the working time can be ensured and it is preferably used in this embodiment from the cost aspect.

[0058] Considering the workability of applying the moisture-curing adhesive to the embedded formwork material, it is preferable that the modified silicone resin adhesive has a viscosity of 50 Pa·s to 900 Pa·s or less at 23°C. When the viscosity of the modified silicone resin adhesive is less than 50 P·s, the fluidity increases, and the adhesive applied to the side surface of the embedded formwork member drips, making it impossible to apply the adhesive to the desired position, ensuring the application amount per unit area required for adhesion, and ensuring adhesion stability. On the other hand, when the viscosity of the modified silicone resin adhesive exceeds 900 Pa·s, the fluidity tends to decrease, not only taking time for the application work, but also the area of the adhesive applied to the surface (top / bottom / sides) of the embedded formwork member is small due to butting with other lightweight embedded formwork members, and there is a tendency that the area required for adhesion cannot be ensured.

[0059] (Method for manufacturing an embedded formwork) The method for manufacturing the embedded formwork according to the present embodiment (hereinafter sometimes referred to as the present manufacturing method) is a method for assembling the above-described embedded formwork 10. The object of the manufacturing method is a formwork assembly having a plurality of embedded formwork members made of a polystyrene-based resin foam and an airtight waterproof material, and is an embedded formwork for forming a hollow portion inside a reinforced concrete structure. And the manufacturing method includes a coating step, an adhesion step, and an airtight waterproof material installation step. In the coating step, a moisture-curing adhesive is applied to the adhesion surface between the embedded formwork members. In the adhesion step, the adhesion surfaces are brought into contact with each other, and the embedded formwork members are adhered to each other in the horizontal and vertical directions to manufacture a formwork assembly. In the airtight waterproof material installation step, the airtight waterproof material is provided at the joint portion between the embedded formwork members on the outer surface of the formwork assembly. According to the method for manufacturing the embedded formwork according to the present embodiment, the embedded formwork members can be stably fixed to each other, and it is possible to make it difficult for concrete paste or rainwater to penetrate into the gaps between the embedded formwork members.

[0060] The place where the present manufacturing method is implemented is not particularly limited. The present manufacturing method may be separately implemented at an assembly location different from the construction site of the reinforced concrete structure. Also, the present manufacturing method may be implemented inside the hollow portion of the reinforced concrete structure.

[0061] (Example of implementing this manufacturing method at another assembly location) If the above coating process, the above bonding process, and the above airtight waterproofing material installation process are carried out at another assembly location, this manufacturing method is not particularly limited. For example, the manufacturing method may be implemented by applying the assembly method of the embedded formwork disclosed in Japanese Patent Application Laid-Open No. 2022-164141.

[0062] (Example of implementing this manufacturing method inside the hollow part of a reinforced concrete structure) If the above coating process, the above bonding process, and the above airtight waterproofing material installation process are carried out inside the hollow part of a reinforced concrete structure, this manufacturing method is not particularly limited. Figure 10 is a diagram schematically showing the procedure of this manufacturing method when implemented inside the hollow part of a reinforced concrete structure.

[0063] In this manufacturing method, first, on the foundation of a reinforced concrete structure in which main reinforcement bars and hoop reinforcement bars are embedded, the embedded formwork member 1 that constitutes the lowermost layer (the layer located on the most HDb side; the first stage) of the formwork assembly 2 is placed so that no step occurs with the foundation. These embedded formwork members 1 are trimmed to a predetermined size.

[0064] Then, in order to integrate the embedded formwork members 1 for the lowermost layer with each other, an adhesive 9, which is a moisture-curing type adhesive, is applied to the side surfaces of the embedded formwork members 1 (coating process; step (i) in Figure 10), and the embedded formwork members 1 are joined together (step (ii) in Figure 10). At this time, in order to ensure accurate positioning and joining when joining the embedded formwork members 1, for example, the fastening fitting 8 shown in Figure 7 is arranged so as to straddle the boundary between the embedded formwork members 1, and the embedded formwork members 1 are joined together with the adhesive 9.

[0065] Perform steps (i) and (ii) of FIG. 10 to complete the lowermost assembly (first-stage assembly) of the formwork assembly 2. Then, for the lowermost assembly, apply an adhesive 9 to the joints between the embedded formwork members 1 on the HDa side, and cover the joints between the embedded formwork members 1 on the horizontal side surface (outermost surface) with an airtight waterproof material. By covering with this airtight waterproof material, it is possible to prevent the intrusion of concrete paste (slurry) generated by the placement of concrete during the construction of the peripheral wall portion of the reinforced concrete structure.

[0066] Regarding the lowermost assembly of the formwork assembly 2, after confirming the curing of the adhesive 9 and the joining of the embedded formwork members 1, place the second-stage embedded formwork member 1 on the HDa-side surface of the lowermost assembly (step (iii) of FIG. 10). At this time, in order to maintain smoothness without creating a step between the lowermost (first stage) and the second stage so that the application and curing of the adhesive 9 can be performed reliably, remove the earth and sand on the HDa-side surface of the lowermost assembly of the formwork assembly 2. Then, apply the adhesive 9 to the lower surface of the second-stage embedded formwork member 1 and join it to the lowermost embedded formwork member 1. Also at this time, when joining the embedded formwork members 1, in order to ensure accurate positioning in the horizontal direction and the HD direction, arrange, for example, the fastening fittings 8 shown in FIG. 7 so as to straddle the boundary between the embedded formwork members 1, and join the embedded formwork members 1 with the adhesive 9 (step (iv) of FIG. 10). Perform steps (iii) and (iv) of FIG. 10 to complete the second-stage assembly of the formwork assembly 2. Then, for the second-stage assembly, apply an adhesive 9 to the joints between the embedded formwork members 1 on the HDa side, and cover the joints between the embedded formwork members 1 on the horizontal side surface (outermost surface) with an airtight waterproof material.

[0067] Similarly, sequentially place the embedded formwork members 1 so as to form the third-stage assembly and the fourth-stage assembly, and join the embedded formwork members 1. Then, after assembling the embedded formwork members 1 up to the uppermost layer, apply an adhesive 9 to the joints on the HDa-side surface of the uppermost-layer assembly, and bond a plywood to the embedded formwork member 1 on the top plate portion of the uppermost-layer assembly with an adhesive.

[0068] Since the above method does not fix the embedded formwork member 1 with the fixing reinforcing bars 6, the through holes 7 as shown in Fig. 1 are not formed in the embedded formwork member 1. However, it goes without saying that this manufacturing method may include a step of fixing the embedded formwork member 1 with the fixing reinforcing bars 6 using the embedded formwork member 1 in which the through holes 7 as shown in Fig. 1 are formed.

Example

[0069] Hereinafter, embodiments of the present invention will be specifically described based on examples. First, the raw materials used in the examples and comparative examples are shown below.

[0070] [Embedded formwork member] Bead method polystyrene-based resin foam (Kaneparl Soil Block D20 manufactured by Kaneka Corporation, unit volume weight: 0.20 kN / m 3 , allowable compressive stress: 50 kN / m 3 ) [Adhesive] (A-1) Moisture-curing modified silicone resin-based resin adhesive (Bond PX280C-X 2way pack manufactured by Konishi Co., Ltd., viscosity: 60 - 150 Pa·s) (A-2) Moisture-curing modified silicone resin-based resin adhesive (SG-1·L manufactured by Cemedine Co., Ltd., viscosity: 270 Pa·s) (A-3) SBR-based resin adhesive (Bond Spray Varnish Z-3 manufactured by Konishi Co., Ltd.) [Airtight waterproof material] (B-1) Acrylic-based airtight waterproof tape (Building Acrylic-based Airtight Waterproof Tape Bond VF420A manufactured by Konishi Co., Ltd., release paper / acrylic adhesive layer (thickness 100 μm) / PE cloth (yellow)) (B-2) Butyl rubber waterproof tape (Building Butyl Rubber-based Waterproof Tape Single-sided Adhesive Bond VF414Z manufactured by Konishi Co., Ltd., release paper / butyl rubber-based adhesive (thickness 75 μm) / PET non-woven fabric) (B-3) Masking tape (Floor curing tape (Sakura) manufactured by Nitto Denko Corporation, PE film (peach) / acrylic adhesive layer (thickness 31 μm)).

[0071] For the embedded formwork materials obtained in each of the examples and comparative examples, tests and evaluations were respectively carried out according to the following procedures.

[0072] [Adhesion strength] A predetermined amount of adhesive was applied to the surface of a foam test piece (50 mm thick × 1000 mm long × 500 mm wide), and then it was bonded to a non - adhesive - coated foam test piece of the same size, and the bonding was carried out. A weight of 5 Kg / m 2 was placed on the bonded object with a weight so that it became, and it was left standing for one day and night (about 12 hours). Then, from the central part in the width direction of the bonded object, it was cut in the length direction with a heat ray, and from the cut surface, an evaluation test piece with a size of 50 mm square with the bonding side at the center was cut out to prepare a sample for adhesion strength. Using an autograph (Autograph AG - 20kNG manufactured by Shimadzu Corporation), a tensile test was carried out at a tensile speed of 5 mm / min with the bonding surface being approximately at the center of the sample.

[0073] (Evaluation criteria) Good: The breaking stress is 200 kN / m 2 or more, and the foam is material - broken Fair: The breaking stress is 100 kN / m 2 or more, or partial delamination is confirmed at the bonding interface of the foam Poor: The breaking stress is less than 100 kN / m 2 or delamination is confirmed at the bonding interface of the foam.

[0074] [Sealing performance] From the test piece that was bonded in the adhesion strength test and cut with a heat ray, a test piece for sealing performance evaluation (50 mm thick × 25 mm long × 100 mm wide) with the bonding side at the center was cut out from the cut surface. A sample for sealing performance evaluation was prepared by attaching a tape - shaped airtight waterproof material (25 mm wide) around the bonding side of the sample. The sample for sealing performance evaluation was immersed in water with red aqueous ink added for 16 hours.

[0075] After immersion, the sample for sealing performance evaluation was taken out of the water, the tape - shaped airtight waterproof material was peeled off, and the penetration of moisture into the bonding (interface) surface was evaluated by sensory evaluation with the color.

[0076] (Evaluation Criteria) Good: No penetration of moisture into the bonding interface was observed. Fair: Penetration of moisture into the ends of the bonding interface was observed, but penetration into the central part was not confirmed. Poor: Penetration of moisture into the bonding interface was confirmed.

[0077] Regarding the evaluation of adhesive strength and sealing performance, those rated "Fair" or above were considered to be able to withstand practical use and were passed.

[0078] (Example 1) Using adhesive (A-1), at a bead width of 60 mm, the adhesive (A-1) was applied to the surface of the embedded form member so that the application amount was approximately 2,200 g / m 2 Then, according to the section on [Adhesive Strength], a bonded object was created to obtain a foam test piece.

[0079] Adhesive strength samples were cut out from the obtained foam test pieces, and an adhesive strength test was carried out.

[0080] On the other hand, using an airtight waterproof material (B-1), according to the section on [Sealing Performance], a sample for sealing performance evaluation was prepared and an adhesion evaluation was carried out. The evaluation results are shown in Table 1.

[0081] (Example 2) Using adhesive (A-2), at a bead width of 65 mm, the adhesive (A-2) was applied to the surface of the embedded form member so that the application amount was approximately 2,200 g / m 2 Evaluation was carried out in the same manner as in Example 1, except that the adhesive (A-2) was applied to the surface of the embedded form member. The evaluation results are shown in Table 1.

[0082] (Example 3) Evaluation was carried out in the same manner as in Example 1, except that an embedded form member with moisture sprayed onto its surface by atomization was prepared. The evaluation results are shown in Table 1.

[0083] (Example 4) Evaluation was carried out in the same manner as in Example 1, except that the airtight waterproof material (B-2) was used. The evaluation results are shown in Table 1.

[0084] (Example 5) Evaluation was carried out in the same manner as in Example 1 except that the airtight waterproof material (B-3) was used. The evaluation results are shown in Table 1.

[0085] (Comparative Example 1) Evaluation was carried out in the same manner as in Example 1 except that it was spray-coated on the surface of the embedded formwork member so that the coating amount was about 2,000 g / m 2 using the adhesive (A-3). The evaluation results are shown in Table 1.

[0086] (Comparative Example 2) Evaluation was carried out in the same manner as in Example 1 except that no airtight waterproof material was used. The evaluation results are shown in Table 1.

[0087]

Table 1

Industrial Applicability

[0088] The present invention can be used, for example, in the construction of reinforced concrete structures such as bridges.

Explanation of Signs

[0089] 1, 1a, 1b, 1c Embedded formwork member 2 Formwork assembly 3 Joint part 4 Airtight waterproof material 4a Release agent layer 4b Adhesive layer 4c Base material layer 5 Formwork material 6 Fixing reinforcement (anchor) 7 Through hole 8 Clamping fitting 8a Body 8b, 8c Protrusion 9 Adhesive (moisture-curing adhesive) 10 Embedded form

Claims

1. An embedded formwork for forming a hollow portion inside a reinforced concrete structure, comprising: a formwork assembly having a plurality of embedded formwork members made of a polystyrene resin foam; and an airtight waterproof material, wherein the formwork assembly is configured such that the embedded formwork members are adhered in the horizontal and vertical directions, and a moisture-curing adhesive is provided on the adhesion surface between the embedded formwork members; on the outer surface of the formwork assembly, the airtight waterproof material is provided at the joint portion between the embedded formwork members. An embedded formwork.

2. The embedded formwork according to claim 1, wherein the moisture-curing adhesive contains a modified silicone resin adhesive.

3. The embedded formwork according to claim 2, wherein the modified silicone resin adhesive has a viscosity at 23°C of 50 Pa·s to 900 Pa·s or less.

4. The airtight waterproof material includes a base material layer and an adhesive layer, the adhesive layer has an acrylic resin adhesive layer or a butyl rubber adhesive layer, The thickness of the adhesive layer is 50 μm to 300 μm. The embedded formwork according to any one of claims 1 to 3.

5. The embedded formwork according to claim 4, wherein the color of the base material layer is selected from the group consisting of yellow, green, red, and light blue.

6. The formwork assembly includes a fastening fitting for fastening the embedded formwork members together, the fastening fitting is disposed across at least two adjacent embedded formwork members in the horizontal direction, and has a protrusion portion embedded and fixed to these embedded formwork members. The embedded formwork according to any one of claims 1 to 3.

7. A plurality of anchors are erected on the foundation of the reinforced concrete structure, the formwork assembly has a through hole through which the anchor passes. The embedded formwork according to any one of claims 1 to 3.

8. A method for manufacturing an embedded formwork for forming a hollow portion inside a reinforced concrete structure, comprising: a formwork assembly having a plurality of embedded formwork members made of a polystyrene resin foam; and an airtight waterproof material, the method including: a coating step of applying a moisture-curing adhesive to the adhesion surface between the embedded formwork members; an adhesion step of bringing the adhesion surfaces into contact with each other to adhere the embedded formwork members in the horizontal and vertical directions to manufacture a formwork assembly; and an airtight waterproof material installation step of providing the airtight waterproof material at the joint portion between the embedded formwork members on the outer surface of the formwork assembly.

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