Manufacturing method for precast concrete member, joining method, and joining structure

Abstract

To achieve reducing the effort to remove stop plugs and the effort to repair pulling-out holes in concrete when manufacturing PCa members, and reducing the effort to attach / remove stop plugs and the effort to backfill pulling-out holes in concrete, and reducing deterioration in appearance when joining PCa members.SOLUTION: A discharge cap 1 made of a polymer material is used, which includes a seal part 2 inserted into a discharge pipe 14, a head 7, a neck part 6 narrower than the head 7, and a discharge path 9 penetrating from the seal part 2 to the head 7. The discharge cap 1 is attached with the seal part 2 inserted partway into the discharge pipe 14, and a formwork surface presses the head 7 so that the seal part 2 is further inserted, and concrete is poured to manufacture a first PCa member. This first PCa member and another second PCa member are joined by disposing ends of each reinforcing bar inside a sleeve 10, injecting grout, and discharging it from an opening of the discharge cap 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a manufacturing method, a joining method, and a joining structure for precast concrete members. Hereinafter, precast concrete will be referred to as "PCa." [Background technology]

[0002] A joint structure is known in which a first PCa member and a second PCa member are joined using a grout-filled rebar joint, in which the end of a first rebar inside the first PCa member and the end of a second rebar protruding from the second PCa member are fixed inside a sleeve embedded in the first PCa member via grout such as mortar filled inside the sleeve (Patent Documents 1 to 3).

[0003] <1> Manufacturing and joining of PCa components using stoppers The PCa members are often manufactured and joined as described below in [x] and [y] using stoppers (rubber stoppers with piston bodies as described in Patent Documents 1 and 2, or general rubber stoppers).

[0004] [x] PCa component manufacturing (work in the factory) [x1] As shown in FIG. 13(a), for example, 12 sleeves 60 are arranged in two rows (=6 sleeves×2 rows), and the lower part of a first reinforcing bar 66 is inserted into the sleeve 60 from its upper opening. An injection pipe 62 is inserted into and connected to the grout injection hole 61 of the sleeve 60, and a rubber stopper 51 is attached to the end of the injection pipe 62. A discharge pipe 64 is inserted into and connected to the grout discharge hole 63 of the sleeve 60, and a rubber stopper 51 is attached to the end of the discharge pipe 64. This is to prevent concrete 68 from entering the injection pipe 62 and the discharge pipe 64 in [x3] below. As shown in Figures 13(b) and (c), the rubber stopper 51 consists of an axial seal portion 52 that is inserted into the injection pipe 62 and a head portion 53 that can abut against the end face of the injection pipe 62. If 12 sleeves 60 are used as in the above example, 24 rubber stoppers 51 (= 12 pieces x 2 rows) are required.

[0005] [x2] As shown in Figures 14 and 15, a form 67 is set around the sleeve 60, and the form surface is brought into contact with the head 53 of the rubber stopper 51. However, because there is a limit to the accuracy of the distance and angle of the sleeve 60 or rubber stopper 51 relative to the form surface, this contact can occur in various ways, such as a perfect contact as shown in Figure 16(a), a non-contact situation with a gap as shown in Figure 16(b), a strong pressure as shown in Figure 16(c), or an inclined contact with a gap as shown in Figure 16(d).

[0006] [x3] As shown in Figure 15, concrete 68 is poured into formwork 67. At this time, slag is unlikely to get between the rubber stoppers 51 and the formwork surface in the cases of (a) and (c) in Figure 16, but slag does get in in the cases of (b) and (d).

[0007] [x4] As shown in Figure 17, remove all rubber stoppers 51 from the injection pipes 62 and discharge pipes 64. This is to fill and check the mortar 77 in [y3] below. Holes 69 will be created in the concrete 68 when the heads 53 of the rubber stoppers 51 are removed. If 12 sleeves 60 are used as in the example above, 24 holes 69 will be created (= 12 × 2 sides). If slag gets in, as shown in Figure 16(b)(d), the holes 69 that are created there will have cracked edges, causing the shape to become distorted, and will need to be repaired. In this way, the first PCa member 65 is completed.

[0008] [y] Joining PCa members (work at construction site) [y1] As shown in Figure 18, a separately prepared second PCa member 72 is placed on the underside of the first PCa member 65, and the upper part of the second reinforcing bar 73 protruding from the top surface of the second PCa member 72 is inserted into the interior through the lower opening of the sleeve 60.

[0009] [y2] As shown in Figure 18, the stopper body 56 of the piston-equipped stopper 55 described in Patent Document 2 is attached to the end of the discharge pipe 64, and the pressure-receiving body 58 of the piston body 57 is separated from the stopper body 56 and positioned deep inside the discharge pipe 64. In the above example, it is necessary to attach 12 piston-equipped stopper plugs 55 (= 6 pieces × 2 faces), which is time-consuming.

[0010] [y3] As shown in Figures 18 and 19, an injection nozzle 76 connected to a mortar pump (not shown) is inserted into the injection pipe 62 of one of the sleeves 60, and mortar 77 is injected into the interior of that sleeve 60. When the mortar 77 reaches the discharge pipe 64, it pushes the pressure-receiving body 58, displacing the piston body 57 outward, allowing confirmation that the mortar 77 has been filled. The injection nozzle 76 is removed from the injection pipe 62, and as shown in Figure 20(a), a stop plug with piston body 55 is quickly attached to the injection pipe 62 to prevent the pre-hardened mortar 77 from flowing out. The injection nozzle 76 is replaced with another injection pipe 62, and the injection of mortar 77 is repeated for each sleeve 60 (individual injection method). Note that the mortar 77 is also filled into the joint space 75 formed between the first PCa member 65 and the second PCa member 72 from the lower opening of the sleeve 60.

[0011] [y4] As shown in Figure 20(b), after the mortar 77 has hardened, the piston-equipped stopper 55 is removed from the injection pipe 62 and the discharge pipe 64. In the above example, it is necessary to remove 24 piston-equipped stopper 55 (= 12 pieces × 2 sides), which is time-consuming.

[0012] [y5] As shown in Figure 20(c), the area from the trace holes 69 in the concrete 68 to the ends of the injection pipe 62 and the discharge pipe 64 is filled with a filler 78 (e.g., mortar). If there are as many as 24 trace holes 69 (= 12 × 2 sides) as in the above example, the filling is time-consuming. Also, as shown in Figures 21 and 22, the filler 78 stands out because it is a different color from the surrounding concrete 68, so if there are a large number of them, the aesthetic appearance will be impaired.

[0013] <2> Manufacturing and joining of PCa members using flap-equipped lids Additionally, Patent Document 3 proposes that the PCa member be manufactured and joined as follows using a flap-equipped lid having a check valve function.

[0014] When manufacturing PCa components, flap-equipped lids are fitted and fixed to the outside of the sleeve's injection and discharge holes beforehand, so the flap-equipped lids are embedded in the concrete component. However, because the flap-equipped lids are located deeper inside the concrete component's mortar injection and exhaust ports, it is necessary to attach and remove separate stop plugs to form these injection and exhaust ports.

[0015] When joining PCa components, a nozzle is inserted into the injection port of the concrete component, and the mortar injected under the pressure of the mortar pump opens the flap-equipped lid at the back of the injection port, enters the sleeve, and opens the flap-equipped lid at the back of the exhaust port, allowing the mortar to flow out through the exhaust port. This outflow can be used to confirm filling. When the mortar pump is then stopped and the nozzle is pulled out, the flap-equipped lid elastically closes, sealing the injection port and exhaust port, preventing the mortar from leaking out without the need for a stopper. However, because the flap-equipped lid is located deeper than the injection port and exhaust port, the injection port and exhaust port of the concrete component must be filled in later. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Japanese Patent Application Publication No. 9-209506 (Patent No. 3277482) [Patent Document 2] JP 2009-13735 A (Patent No. 4870624) [Patent Document 3] Japanese Patent Application Publication No. 11-343703 Summary of the Invention [Problem to be solved by the invention]

[0017] the above <1> When PCa members are manufactured and joined using stop plugs as described above, there are problems such as the large number of stop plugs that need to be removed during the manufacture of the PCa members, which is time-consuming, and the large number of holes that need to be repaired after the stop plugs are removed, which is time-consuming.In addition, when joining PCa members, there are problems such as the large number of stop plugs that need to be attached and removed, which is time-consuming, and the large number of holes that need to be filled later, which is time-consuming and deteriorates the aesthetic appearance.

[0018] the above <2> When using a flap lid to manufacture and join PCa members as shown above, there is a problem that although the flap lid is left in place and does not need to be removed when manufacturing the PCa members, it is necessary to attach and remove a separate stopper. Also, when joining PCa members, there are many problems with the large number of injection and exhaust ports for the concrete members that are subsequently buried, which is time-consuming and detracts from the aesthetic appearance.

[0019] Therefore, an object of the present invention is to reduce the labor required to remove stop plugs and repair holes in the concrete when manufacturing PCa members. Also, an object of the present invention is to reduce the labor required to attach and remove stop plugs and to reduce the labor required to fill holes in the concrete when joining PCa members, thereby reducing deterioration of the appearance. [Means for solving the problem]

[0020] [1] In a manufacturing method of PCa components in which a sleeve for a grout-filled rebar joint is embedded, a discharge cap made of a polymer material, the discharge cap including a seal portion inserted into the discharge pipe, a head portion disposed on the outside of the discharge pipe, a neck portion between the seal portion and the head portion and narrower than the head portion, and a discharge passage extending from the seal portion to the head portion, is attached to the discharge pipe connected to the grout discharge hole of the sleeve with the seal portion halfway inserted into the discharge pipe; A mold is set around the sleeve, and at this time, the mold surface presses the head so that the seal portion is further inserted into the discharge pipe. A method for manufacturing PCa components, characterized by pouring concrete inside a formwork.

[0021] [2] A method for joining PCa members, which joins a first PCa member in which a sleeve for a grout-filled rebar joint is embedded and a second PCa member, A discharge cap made of a polymeric material is attached to a discharge pipe connected to the grout discharge hole of the sleeve, the discharge cap including a seal portion inserted into the discharge pipe, a head portion whose outer end is aligned with the surface of the first PCa member, a neck portion between the seal portion and the head portion and narrower than the head portion, and a discharge path passing through from the seal portion to the head portion; An end of the first reinforcing bar inside the first PCa member and an end of the second reinforcing bar protruding from the end face of the second PCa member are placed inside the sleeve, A method for joining PCa members, characterized in that grout is injected into the inside of the sleeve to fill it, and then discharged from the opening at the head of the discharge channel of the discharge cap.

[0022] In the above [2], it is preferable that multiple sleeves are arranged in a row, a joint space is formed between the end face of the first PCa member and the end face of the second PCa member, the openings on the end face of each sleeve are connected to the joint space, and mortar is injected from some of the sleeves and filled into all of the sleeves through the joint space (one-shot injection method).

[0023] [3] A joint structure of PCa members in which a first PCa member and a second PCa member are joined by a grout-filled rebar joint in which the end of a first rebar inside the first PCa member and the end of a second rebar protruding from the end face of the second PCa member are fixed inside a sleeve embedded in the first PCa member via grout filled inside the sleeve, A PCa member joint structure characterized in that a discharge cap made of a polymeric material is attached to a discharge pipe connected to a grout discharge hole in the sleeve, the discharge cap including a seal portion inserted into the discharge pipe, a head whose outer end is aligned with the surface of the first PCa member, a neck portion between the seal portion and the head that is thinner than the head, and a discharge path that passes from the seal portion to the head.

[0024] [4] A discharge cap attached to a discharge pipe connected to a grout discharge hole of a sleeve for a grout-filled rebar joint, The discharge cap includes a seal portion inserted into the discharge pipe, a head portion disposed outside the discharge pipe, a neck portion between the seal portion and the head portion that is thinner than the head portion, and a discharge passage that passes through from the seal portion to the head portion, and is made of a polymeric material.

[0025] [5] In the above items [1] to [4], it is preferable that the discharge cap includes a lid portion located between the seal portion and the neck portion and having a larger outer diameter than the discharge pipe.

[0026] [6] In the above items [1] to [5], the seal portion preferably includes a shaft and a ring-shaped plate-like rib protruding from the outer peripheral surface of the shaft.

[0027] [7] In the above items [1] to [6], it is preferable that the head has an end face recessed toward the center, and the periphery of the end face is the outer end.

[0028] [8] In the above [7], it is preferable to removably attach a closing sheet for closing the opening of the discharge passage to a portion of the end face of the head that does not overlap the periphery of the end face before setting the formwork. [Effects of the Invention]

[0029] According to the present invention, when manufacturing PCa members, the labor required to remove stop plugs and repair holes in the concrete can be reduced. Also, when joining PCa members, the labor required to attach and remove stop plugs can be reduced, the labor required to fill holes in the concrete can be reduced, and deterioration of the appearance can be reduced. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 shows a process of arranging sleeves in two rows in an embodiment, where (a) is a perspective view, (b) is a perspective view of a discharge cap to be used, and (c) is a cross-sectional view of the same discharge cap. [Figure 2] FIG. 2 shows the formwork installation step in the embodiment, where (a) is a perspective view, (b) is a cross-sectional view of the upper part, and (c) is a cross-sectional view of the lower part. [Figure 3]FIG. 3 shows a concrete pouring process in the embodiment, where (a) is a longitudinal cross-sectional view in the inter-row direction, and (b) is a longitudinal cross-sectional view in the row direction. [Figure 4] FIG. 4 shows a formwork installation step and a concrete pouring step in an embodiment, and (a) to (d) are cross-sectional views showing discharge caps in various cases. [Figure 5] FIG. 5 shows a demolding process for a first PCa member in the embodiment, where (a) is a longitudinal cross-sectional view in the inter-row direction, and (b) is a longitudinal cross-sectional view in the row direction. [Figure 6] FIG. 6 is a perspective view of the first PCa member and the second PCa member when they are brought close to each other in the embodiment. [Figure 7] FIG. 7 is a perspective view of the first PCa member and the second PCa member in the embodiment when they are joined together. [Figure 8] FIG. 8 shows a mortar injection step in the example, where (a) is a longitudinal cross-sectional view in the inter-row direction, and (b) is a longitudinal cross-sectional view in the row direction. [Figure 9] FIG. 9 shows the end of the mortar injection step in the example, where (a) is a longitudinal cross-sectional view in the inter-row direction, and (b) is a longitudinal cross-sectional view in the row direction. [Figure 10] Figure 10(a) is a longitudinal cross-sectional view of an embodiment in which a stopper is attached to an injection pipe after mortar injection, (b) is a longitudinal cross-sectional view of an embodiment in which the stopper is removed, and (c) is a longitudinal cross-sectional view of an embodiment in which the hole is filled with a filler material. [Figure 11] FIG. 11 is a perspective view of a joint of a box culvert in the embodiment. [Figure 12] FIG. 12 is a perspective view of the entire box culvert in the embodiment. [Figure 13] FIG. 13 shows a process for arranging sleeves in two rows in a conventional example, where (a) is a perspective view of the rubber stopper used, and (b) is a cross-sectional view of the same rubber stopper. [Figure 14] FIG. 14 shows a formwork installation process in a conventional example, where (a) is a perspective view, (b) is a cross-sectional view of the upper part, and (c) is a cross-sectional view of the lower part. [Figure 15] FIG. 15 shows a concrete pouring process in a conventional example, where (a) is a longitudinal cross-sectional view in the inter-row direction, and (b) is a longitudinal cross-sectional view in the row direction. [Figure 16] FIG. 16 shows a formwork installation process and a concrete pouring process in a conventional example, and (a) to (d) are cross-sectional views showing rubber stoppers in various cases. [Figure 17] FIG. 17 shows a process for demolding a first PCa member in a conventional example, where (a) is a vertical cross-sectional view in the inter-row direction, and (b) is a vertical cross-sectional view in the row direction. [Figure 18] FIG. 18 shows a conventional example during the mortar injection process, where (a) is a longitudinal cross-sectional view in the inter-row direction, and (b) is a cross-sectional view of the stopper used. [Figure 19] FIG. 19 shows the time when the mortar injection process is completed in the conventional example, where (a) is a longitudinal cross-sectional view in the inter-row direction, and (b) is a longitudinal cross-sectional view in the row direction. [Figure 20] Figure 20(a) is a longitudinal cross-sectional view of a conventional example in which a stopper is attached to an injection pipe after mortar injection, (b) is a longitudinal cross-sectional view of the injection pipe when the stopper is removed, and (c) is a longitudinal cross-sectional view of the injection pipe when the hole is filled with a filler material. [Figure 21] FIG. 21 is a perspective view of a joint of a conventional box culvert. [Figure 22] FIG. 22 is a perspective view of the entire conventional box culvert. DETAILED DESCRIPTION OF THE INVENTION

[0031] 1. PCa members Examples of PCa members include, but are not limited to, PCa members for constructing various civil engineering structures such as box culverts, sheds, waterways, and retaining walls.

[0032] 2. Sleeve The sleeve is not particularly limited, but various commercially available sleeves (for example, "Splice Sleeve" from Japan Splice Sleeve Co., Ltd.) can be used.

[0033] 3. Grout The grout is not particularly limited, but mortar is preferred because of its adhesiveness to concrete and ease of handling, and non-shrink mortar is particularly preferred.

[0034] 4.Discharge cap The polymeric material for the discharge cap is not particularly limited, but examples include synthetic resin, rubber, elastomer, etc. Thermoplastic elastomers are easy to obtain the elasticity necessary to provide the ring-shaped rib and neck with appropriate elasticity. Olefin-based thermoplastic elastomers or polyester-based thermoplastic elastomers are particularly preferred because they have heat resistance that prevents deformation due to the heat of concrete curing and weather resistance that allows them to be used in environments exposed to ultraviolet rays for many years. The color of the discharge cap is not particularly limited, but it is preferably the color of the concrete of the PCa member (substantially the same color) or white, because the exposed head is less noticeable.

[0035] The front shape of the head is not particularly limited, but a circular shape is preferable, since this allows the periphery to easily contact the formwork surface with a uniform force. The recess on the end face of the head is not particularly limited, but is preferably 0.5 to 2 mm, because this allows the closure sheet to be attached, creates a suction cup effect, and does not weaken the head. The outer diameter of the outer end of the head (exposed to the outside) is not particularly limited, but is preferably 10 to 28 mm, more preferably 15 to 24 mm, because if the outer diameter is small, it is less noticeable even when exposed to the outside. The outer diameter of the inner end of the head may be the same as the outer diameter of the outer end, or may be larger than the outer diameter of the outer end. The thickness of the head is not particularly limited, but is preferably 4 to 8 mm, because this allows the head to fit easily into a mold and makes it less likely to bend.

[0036] The outer diameter of the neck is not particularly limited, but is preferably 7 to 12 mm, more preferably 8 to 11 mm, because it is flexible and has the strength to maintain the inner diameter of the discharge passage. The length of the neck is not particularly limited, but is preferably 3 to 8 mm, and more preferably 4 to 7 mm, because it is easily flexible, easily compressed in the lengthwise direction, and easily fits into a mold. Although it depends on the polymer material, if the neck, outer diameter, and length are on this order, it is easy to obtain a suitable degree of flexibility.

[0037] The outer diameter of the lid is not particularly limited, but is preferably 1 to 5 mm larger than the outer diameter of the discharge pipe, because this makes it easier to grip the lid and to fit it into the mold. The thickness of the lid is not particularly limited, but is preferably 3 to 7 mm, because this makes the lid less likely to bend and easier to fit into the mold.

[0038] The number of ring-shaped plate-like ribs is not particularly limited, but it is preferable to have more than one, and more preferably three to five, in view of the sealing properties of the sealing portion and posture stability.

[0039] The inner diameter of the opening at the head of the discharge channel is not particularly limited, but is preferably 1.5 to 5 mm, more preferably 2 to 4 mm. If this inner diameter is less than 1.5 mm, mortar aggregates tend to clog, and if it exceeds 5 mm, too much mortar tends to be discharged. However, if too much mortar is discharged, this can be adjusted by inserting a shaft thinner than the opening into the opening, so there is no problem. The inner diameter of the discharge passage at the sealed portion is preferably larger than that of the opening, because this allows the mortar to flow easily. [Example]

[0040] Next, an embodiment in which the present invention is embodied in a joint structure for PCa members that constitute a box culvert will be described with reference to Figures 1 to 12. Note that the structure, material, shape, and dimensions of each part in the embodiment are examples and can be changed as appropriate without departing from the spirit of the invention.

[0041] As shown in Figure 12, a box culvert is constructed by joining an upper first PCa member 15 and a lower second PCa member 22, which are divided into two at the middle of the side wall, and then connecting the joined bodies in the length direction of the culvert. In this embodiment, the first PCa member 15 is manufactured, and a separately manufactured second PCa member 22 is joined to the first PCa member 15. First, we will explain the known sleeve 10 and new discharge cap 1 used in the embodiment.

[0042] [sleeve] As shown in Figures 1(a) and 3, the sleeve 10 is a steel cylindrical body with a lower opening at its lower end surface and an upper opening at its upper end surface, with a grout injection hole 11 formed near the lower end of the cylindrical wall and a grout discharge hole 13 formed near the upper end of the cylindrical wall. The sleeve 10 is positioned deep inside at a predetermined distance from the surface of the PCa member, and an injection pipe 12 of a predetermined length is connected to the grout injection hole 11 by insertion or the like, and a discharge pipe 14 of a predetermined length is also connected to the grout discharge hole 13 by insertion or the like. The injection pipe 12 and the discharge pipe 14 are generally made of a polymer material such as polyvinyl chloride.

[0043] [Discharge cap] As shown in Figures 1(b) and 1(c), the discharge cap 1 is made of a polymer material (thermoplastic elastomer in this example) and includes a seal portion 2 inserted into the discharge pipe 14, a head portion 7 arranged on the outside of the discharge pipe 14, a neck portion 6 located between the seal portion 2 and the head portion 7 and thinner than the head portion 7, a lid portion 5 located between the seal portion 2 and the neck portion 6 and larger than the outer diameter of the discharge pipe 14, and a discharge channel 9 passing through from the seal portion 2 to the head portion 7.

[0044] The head 7 has a truncated cone shape with an outer diameter of 19 to 21 mm at the front end and 23 to 26 mm at the rear end, and a thickness of 5 to 7 mm. The head 7 has an end face that is recessed 0.8 to 1.2 mm toward the center, and the periphery of the end face is the outer end, which has the following effects. A closing sheet 8 that closes the opening of the discharge channel 9 can be removably attached to a portion of the end face of the head 7 that does not overlap the periphery, thereby preventing slag from entering the discharge channel 9 when pouring concrete. The contact pressure of the periphery of the head 7 against the formwork surface is increased, and the concave end surface also acts as a suction cup, preventing slag from getting into the end surface when concrete is poured.

[0045] The neck portion 6 has a cylindrical shape that is thinner than the head portion 7, with an outer diameter of 9 to 10 mm and a length of 4 to 6 mm, and is easily flexible and easily compressed in the longitudinal direction. Therefore, as will be described later, the entire periphery (outer end) of the head portion 7 acts to abut against the formwork surface.

[0046] The lid portion 5 has a disk shape larger than the outer diameter of the discharge pipe 14, with a diameter 4 mm larger than the outer diameter of the discharge pipe 14 and a thickness of 4 to 6 mm, making it easy to grip and difficult to bend when gripped.

[0047] The seal portion 2 includes a shaft 3 and three ring-shaped plate-shaped ribs 4 protruding from the outer peripheral surface of the shaft 3. The outer diameter of the shaft 3 is smaller than the inner diameter of the discharge pipe 14, and the outer diameter of the ring-shaped plate-shaped ribs 4 is larger than the inner diameter of the discharge pipe 14. Therefore, when inserted into the discharge pipe 14, the ring-shaped plate-shaped ribs 4 bend in the direction opposite to the insertion direction and press against the inner surface of the discharge pipe 14 (FIG. 1(c)). The presence of these three pressed ring-shaped plate-shaped ribs 4 makes it difficult for the shaft 3 to slip out of the discharge pipe 14.

[0048] In the embodiment, the PCa member is manufactured and joined using the above-mentioned discharge cap 1 and a general rubber stopper as follows [X] and [Y].

[0049] [X] Precast concrete component manufacturing (work in the factory) [X1] As shown in FIG. 1, for example, 12 sleeves 10 are arranged in two rows (= 6 sleeves × 2 rows), and the lower part of the first reinforcing bar 16 is inserted into the sleeve 10 from its upper opening. As shown in Figures 1(a) and 2(c), grout injection holes 11 of two sleeves 10 at both ends of each row are connected by inserting injection pipes 12 of a predetermined length, and relatively short injection pipes 12 are inserted and connected to the injection holes of the other four sleeves 10. The end of each injection pipe 12 is fitted with the general rubber stopper 51 shown in Figure 13(b) above. This is to prevent concrete 18 from entering the injection pipe 12 at [X3] below. If 12 sleeves 10 are used as in the above example, 12 rubber stoppers 51 (= 6 x 2 rows) are required.

[0050] As shown in Figures 1(a)-(c) and 2(b), a predetermined length of discharge pipe 14 is inserted and connected to the grout discharge hole 13 of the sleeve 10, and a discharge cap 1 is attached to the end of the discharge pipe 14. A closure sheet 8 is attached to the end face of the discharge cap 1 to close the opening of the discharge channel 9. This is to prevent concrete 18 from entering the discharge pipe 14 in [X3] below, and to allow the filling of mortar 27 to be confirmed in [Y3] below (by peeling off the closure sheet 8). The discharge cap 1 is attached with the sealing portion 2 partially inserted into the discharge pipe 14. An example of this state is when two ring-shaped plate-shaped ribs 4 are inserted into the discharge pipe 14 and the remaining ring-shaped plate-shaped rib 4 protrudes from the discharge pipe 14. If twelve sleeves 10 are used as in the example above, twelve discharge caps 1 (= six caps x two rows) are required.

[0051] [X2] As shown in FIG. 2, a mold 17 is set around the sleeve 10. At this time, as shown in Figures 2(b) and 3, the formwork surface presses against the head 7 of the discharge cap 1, causing the seal portion 2 to be further inserted into the discharge pipe 14. Because there are limits to the accuracy of the distance and angle of the sleeve 10 or discharge cap 1 relative to the formwork surface, there are cases in which the outer edge of the head 7 abuts the formwork surface at the same time as the lid portion 5 abuts against the discharge pipe 14, as shown in Figure 4(a); in which the outer edge of the head 7 abuts the formwork surface without the lid portion 5 abutting against the discharge pipe 14, as shown in Figure 4(b); in which the lid portion 5 abuts against the discharge pipe 14, the neck portion 6 is compressed, and the outer edge of the head 7 abuts the formwork surface, as shown in Figure 4(c); or in which the neck portion 6 is tilted and bent, causing the outer edge of the head 7 to abut against the formwork surface, as shown in Figure 4(d). However, in all cases, the outer edge of the head 7 abuts the formwork surface perfectly without any gaps.

[0052] At this time, as shown in Figures 2(c) and 3, the formwork surface abuts against the heads 53 of the rubber stoppers 51 attached to the injection pipes 12 of the two sleeves 10 at both ends of each row. These rubber stoppers 51 may not abut perfectly against the formwork surface, leaving gaps, as shown in Figures 16(b) and (d) above. However, the rubber stoppers 51 attached to the injection pipes 12 of the other four sleeves 10 are intentionally not abutted against the formwork surface in order to prevent the formation of trace holes 19, as will be described later.

[0053] [X3] As shown in Figure 3, concrete 18 is poured into formwork 17. At this time, in any of the cases shown in Figures 4(a) to (d), slag is unlikely to get in between the head 7 of the discharge cap 1 and the formwork surface. As for the rubber stoppers 51 at both ends of each row, slag will get in if a gap is formed between them and the formwork surface as described above.

[0054] [X4] As shown in Figure 5, remove the rubber stoppers 51 from the injection pipes 12 at both ends of each row. This is to fill with mortar 27 in [Y3] below. A hole 19 is created in the concrete 18 when the head 53 of the rubber stopper 51 is removed. If slag gets in as described above, the hole 19 that is created there will have its edges cracked, causing it to become misshapen, and it will need to be repaired. However, if 12 sleeves 10 are used as in the example above, only four holes 19 (= 2 × 2 sides) will be created, reducing the effort required for repairs.

[0055] Meanwhile, the discharge cap 1 is left in place without being removed. In this way, the first PCa member 15 is completed. The end face of the head 7 of the discharge cap 1 is exposed to the outside, and the periphery (outer edge) of this end face is aligned with the surface of the first PCa member 15, and the shape of the concrete 18 around this end face is not disturbed, so there is no need to repair the hole 19. In addition, a first recess 20 for forming a joint space 25 described later is formed in the lower end surface of the first PCa member 15, and the lower opening of the sleeve 10 communicates with the first recess 20.

[0056] [Y] Joining PCa members (work at construction site) [Y1] As shown in Figures 6 to 8, a separately prepared second PCa member 22 is aligned with the underside of the first PCa member 15, and the upper portions of the second reinforcing bars 23 protruding from the upper surface of the second PCa member 22 are inserted into the interior through the lower opening of the sleeve 10. A second recess 24 is formed in the upper end surface of the second PCa member 22, and a joint space 25 is formed by the first recess 20 and the second recess 24.

[0057] [Y2] As shown in Figure 8, the closing sheet 8 is peeled off from the end face of the discharge cap 1 to open the opening of the discharge passage 9. Since the discharge cap 1 can be left in place, there is no need to attach a stopper (such as the stopper with piston body described above) as in the past, which saves time and effort.

[0058] [Y3] As shown in Figures 8 and 9, injection nozzles 26 connected to a mortar pump (not shown) are inserted into the injection pipes 12 at both ends of each row, and mortar 27 is injected into the sleeves 10. The mortar 27 flows inside the sleeves 10 at both ends of each row, flows into the joint spaces 25, and also flows into the interiors of the other four sleeves 10, filling them. When the mortar 27 reaches the discharge pipes 14, it flows through the discharge channel 9 of the discharge cap 1 and is discharged to the outside from the opening of the discharge channel 9 in the head 7, so that the filling of the mortar 27 can be confirmed. The discharge of the mortar 27 occurs first at both ends of each row, and then next, as shown in Figure 9(b). The discharged mortar is removed.

[0059] The injection nozzle 26 is removed from the injection pipe 12, and as shown in Figure 10(a), a stopper (such as the piston-body stopper 55) is quickly attached to the injection pipe 12 to prevent the pre-hardened mortar 27 from flowing out. In the above example, it is sufficient to attach four stopper plugs (= two plugs x two sides), which is not time-consuming. In this embodiment, as described above, mortar 27 is injected from the injection pipes 12 of some of the sleeves 10 (in the above example, both ends of each row) and filled into all of the sleeves 10 through the joint spaces 25 (one-shot injection method). Therefore, compared to the individual injection method described above, the effort required to replace the injection nozzle 26 with another injection pipe 12 is reduced, the effort required to attach a piston-equipped stopper is also reduced, and the hole 19 in the concrete 18 required to expose the injection pipe 12 is also reduced.

[0060] [Y4] As shown in Figure 10(b), after the mortar 27 has hardened, the stopper (55) is removed from the injection pipe 12. In the above example, it is only necessary to remove four stopper plugs (= 2 plugs x 2 sides), which is not time-consuming.

[0061] [Y5] As shown in Figure 10(c), the area from the trace holes 19 in the concrete 18 to the end of the injection pipe 12 is filled with a filler 28 (e.g., mortar). In the above example, there are only four trace holes 19 (= 12 × 2 sides), so the filling is not time-consuming. Also, as shown in Figures 11 and 12, even though the filler materials 28 stand out because they are a different color from the surrounding concrete 18, the aesthetic appearance is not significantly impaired because there are only a few of them.

[0062] The present invention is not limited to the above-described embodiments, and can be embodied by making appropriate modifications within the scope of the invention. [Explanation of symbols]

[0063] 1 Discharge cap 2 Seal part 3-axis 4 Ring Plate Rib 5 Lid 6 Neck 7 head 8 Closure Sheet 9 Exhaust channel 10 sleeves 11 Grout injection holes 12 Injection tube 13 Grout discharge hole 14 Discharge pipe 15 First PCa member 16 First Reinforcement Bar 17 Formwork 18 Concrete 19 Atoana 20 First recess 22 Second PCa member 23 Second rebar 24 Second recess 25 Joint space 26 Injection nozzle 27 Mortar 28 Post-filling material 51 Rubber stopper 52 Axial seal 53 Head 55 Stopcock with piston body 56 Plug body 57 Piston body 58 Pressure receiving body 60 sleeves 61 Grout injection hole 62 Injection tube 63 Grout discharge hole 64 Discharge pipe 65 First PCa member 66 First Reinforcement Bar 67 Formwork 68 Concrete 69 Atoana 72 Second PCa member 73 Second Reinforcement Bar 75 Joint space 76 Injection nozzle 77 Mortar 78 Post-filling material

Claims

1. A method for manufacturing a precast concrete member in which a sleeve for a grout-filled reinforcing bar joint is embedded, comprising: a discharge cap made of a polymeric material including a seal portion inserted into the discharge pipe, a head portion disposed outside the discharge pipe, a neck portion between the seal portion and the head portion and narrower than the head portion, and a discharge passage extending from the seal portion to the head portion is attached to the discharge pipe connected to the grout discharge hole of the sleeve with the seal portion halfway inserted into the discharge pipe; A mold is set around the sleeve, and the mold face presses against the head so that the seal portion is further inserted into the discharge pipe; A method for manufacturing a precast concrete member, comprising pouring concrete into a formwork.

2. 2. The method for manufacturing a precast concrete section according to claim 1, wherein the drain cap includes a lid portion located between the seal portion and the neck portion and larger than an outer diameter of the drain pipe.

3. 2. The method for manufacturing a precast concrete member according to claim 1, wherein the sealing portion includes a shaft and a ring-shaped plate-shaped rib protruding from an outer peripheral surface of the shaft.

4. A method for manufacturing a precast concrete section according to any one of claims 1 to 3, wherein the head has an end face that is concave towards the centre, and the periphery of the end face is the outer end.

5. 5. A method for manufacturing a precast concrete member according to claim 4, further comprising the step of removably attaching a closing sheet for closing the opening of the discharge passage to a portion of the end face of the head that does not overlap with the periphery thereof before the formwork is set.

6. A method for joining precast concrete members, comprising joining a first precast concrete member having a sleeve for a grout-filled rebar joint embedded therein to a second precast concrete member, the method comprising the steps of: a drain cap made of a polymeric material is attached to a drain pipe connected to the grout drain hole of the sleeve, the drain cap including a seal portion inserted into the drain pipe, a head portion having an outer end aligned with the surface of the first precast concrete member, a neck portion between the seal portion and the head portion and narrower than the head portion, and a drain passage extending from the seal portion to the head portion; an end of the first reinforcing bar inside the first precast concrete member and an end of the second reinforcing bar protruding from an end face of the second precast concrete member are disposed inside a sleeve; A method for joining precast concrete members, comprising injecting grout into the interior of the sleeve to fill it and then discharging it from an opening at the head of the discharge passage of the discharge cap.

7. A method for joining precast concrete members as described in claim 6, in which a plurality of sleeves are arranged in a row, a joint space is formed between the end face of the first precast concrete member and the end face of the second precast concrete member, the openings on the end face of each sleeve communicate with the joint space, and mortar is injected into some of the sleeves and filled into all of the sleeves through the joint space.

8. A joint structure for precast concrete members in which a first precast concrete member and a second precast concrete member are joined by a grout-filled reinforcing bar joint in which an end of a first reinforcing bar inside the first precast concrete member and an end of a second reinforcing bar protruding from an end face of the second precast concrete member are fixed inside a sleeve embedded in the first precast concrete member via grout filled inside the sleeve, A joint structure for precast concrete members, characterized in that a discharge cap made of a polymeric material is attached to a discharge pipe connected to a grout discharge hole of the sleeve, the discharge cap including a seal portion inserted into the discharge pipe, a head whose outer end is aligned with the surface of the first precast concrete member, a neck portion between the seal portion and the head and narrower than the head, and a discharge passage passing from the seal portion to the head.

9. A drain cap for attaching to a drain pipe connected to a grout drain hole of a sleeve for a grout-filled rebar joint, comprising: The discharge cap includes a seal portion that is inserted into the discharge pipe, a head portion that is disposed outside the discharge pipe, a neck portion that is between the seal portion and the head and that is thinner than the head, and a discharge passage that passes through from the seal portion to the head, and is made of a polymeric material.

10. 10. The drainage cap of claim 9, further comprising a lid portion between the seal portion and the neck portion, the lid portion being larger than an outer diameter of the drainage tube.

11. 10. The drainage cap according to claim 9, wherein the seal portion includes a shaft and a ring-shaped plate-like rib protruding from an outer peripheral surface of the shaft.

12. 12. The discharge cap according to claim 9, wherein the head has an end face that is concave toward the center, and the periphery of the end face is the outer edge.

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