Method for manufacturing end forms for precast concrete members and method for manufacturing precast concrete members

Abstract

To provide a method for producing a precast concrete member, upon production of a precast concrete member, capable of securing the consistency of the joining edge faces of a precast concrete member at high production efficiency while eliminating a large work space, and a method for producing an end form used for the production method.SOLUTION: A method for producing an end form used for producing a precast concrete member 50 in which plural precast concrete members 50 are connected to form a precast concrete structure has: an A step of installing concrete into a form to produce a former end form 1 (10',10); and a step B of producing a latter end form 1 (20',20) using the former end form 1 (10'10) as match cast end forms.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a gable formwork for producing a precast concrete member, and a method for manufacturing a precast concrete member. [Background technology]

[0002] For example, in the construction of bridges such as box girder bridges, the precast segment method is used, in which multiple precast concrete members (segments such as precast box girder members) that have been manufactured in advance as separate pieces in a factory or on-site yard are joined at the bridge site by applying adhesive to the joint interfaces and then prestressed to integrate them. When using the match cast method in this precast segment method, for example, the precast concrete members are manufactured in the order in which they will be connected. Here, the "match cast method" refers to a method of producing new precast concrete members while utilizing already produced precast concrete members as gable formwork. In the match-cast method, a new precast concrete member is produced while using an already-produced precast concrete member as the gable form, and this allows for the matching of the joint end surfaces of both members. However, in the match-cast method, adjacent precast concrete members must be produced one by one in the order of adjacent members, leaving room for improvement in production efficiency. In addition, when producing the next precast concrete member, the adjacent precast concrete member that has already been produced must be installed as the gable form, for example, in a factory, and there are problems in that a large work space is required to install a relatively large precast concrete member, and furthermore, installation work for the gable form (precast concrete member) is required, which is large and heavy.

[0003] The bridges mentioned above include bridges for various purposes, such as road bridges, railway bridges, and waterway bridges, but in the construction of road bridges (deck members), the precast deck is generally installed at the construction site with gaps, and then filling concrete is poured into the gaps. This requires time for on-site construction, and furthermore, there are issues with quality control of the cast-in-place areas (filling areas), and the fact that cast-in-place areas can often become structurally weak points. Thus, one of the main reasons why the standard method for joining precast decks in road bridges is via interfill concrete, and direct joining using adhesive as in the precast segment method described above is not used, is thought to be that precast decks are generally wide, thin components, and it is difficult to establish a manufacturing method for precast decks that ensures consistency between the end faces.

[0004] In view of the above, there is a need for a method of manufacturing precast concrete members for precast concrete structures such as bridges including road bridges, i.e., precast concrete structures formed by connecting a plurality of precast concrete members, which method has good manufacturing efficiency, does not require a large work space, and ensures the integrity of the joint end surfaces even when the precast concrete members are wide and thin.

[0005] Here, Patent Document 1 proposes a method for manufacturing precast segments by the match-cast method, which makes it possible to manufacture precast segments with high linear accuracy. This method for manufacturing precast segments is a method for manufacturing precast segments that constitute a part of a bridge girder in the bridge axis direction, which includes upper and lower decks made of concrete and a plurality of webs connecting the upper and lower decks. Specifically, the method includes the steps of manufacturing a semi-finished member of a precast segment in which the upper and lower decks main bodies, which form the majority of the upper and lower decks, are integrated via webs; providing at least three protrusions on one end surface in the bridge axis direction of the upper and lower decks main bodies; arranging an adjacent precast segment or its semi-finished member adjacent to the semi-finished member in a position where it abuts against the at least three protrusions to form a match-cast end form for the semi-finished member; and pouring concrete or mortar into the gap formed between the semi-finished member and the adjacent precast segment or its semi-finished member to integrate it with the semi-finished member. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-138004 A Summary of the Invention [Problem to be solved by the invention]

[0007] The manufacturing method for precast segments described in Patent Document 1 uses adjacent precast segments that are placed adjacent to semi-finished components as match-cast end formwork when manufacturing the semi-finished components, which requires that the semi-finished components be manufactured in the order in which they are connected. This requires that already-manufactured semi-finished components be installed when manufacturing new semi-finished components, and therefore requires work space for this, making this a manufacturing method that involves issues unique to the match-cast method.

[0008] The object of the present invention is to provide a method for manufacturing precast concrete members for precast concrete structures formed by connecting a plurality of precast concrete members, which is efficient in manufacturing the precast concrete members, does not require a large work space, and can ensure the integrity of the joint end faces of the precast concrete members, as well as a method for manufacturing the gable formwork used in this manufacturing method. [Means for solving the problem]

[0009] In order to achieve the above object, one aspect of the method for manufacturing a gable form for manufacturing a precast concrete member according to the present invention is to A method for manufacturing a gable form used in manufacturing a precast concrete structure by connecting a plurality of precast concrete members, comprising the steps of: Process A involves pouring concrete into the formwork to create the gable formwork A1; The method is characterized by having a process B in which the gable formwork A1 is used as a match-cast gable formwork to produce gable formwork B1.

[0010] According to this embodiment, after the end form A1 is produced, the end form B1 is produced using this end form A1 as a match cast end form, so that two end forms with highly compatible joint end faces can be produced, and these two end forms can be installed at both ends to produce precast concrete members inside. Since this end form is not the precast concrete member itself that forms the precast concrete structure, the decrease in production efficiency caused by producing the precast concrete members in the order of connection is eliminated, and since the end form can be a concrete member with as thin a thickness as possible, a large work space and excessive work effort are not required for its installation, which leads to a reduction in the production cost of the precast concrete members. In addition, since it is a end form made of concrete, it can be easily formed even if the shape of the end of the precast concrete member is complex. Here, "match-cast end form" refers to an already-produced end form made of precast concrete that is used as the end form when producing a new precast concrete member. By producing two types of end form (end form A 1, end form B 1) with assured consistency (precision) of the joint end faces by the production method of this embodiment and using these end form faces to produce precast concrete members, it is possible to resolve the above-mentioned various problems that the conventional match-cast method has while ensuring the same consistency of the joint end faces as when producing new precast concrete members by the conventional match-cast method that directly uses already-produced precast concrete members. Additionally, "Gable Form A1" and "Gable Form B1" refer to the first gable forms produced as a unit with matching joint end surfaces on both sides, and can also be called the first generation gable form unit. For example, by producing multiple units of Gable Form A1 and Gable Form B1, and using each gable form unit simultaneously, it becomes possible to produce multiple precast concrete members with matching joint end surfaces at once, dramatically improving the efficiency of producing precast concrete members. Examples of precast concrete components that can be produced using the gable formwork produced by the production method of this embodiment include precast decks and precast box girder components for road bridges, and by connecting multiple of these precast concrete components to each other, precast concrete structures such as road bridges and bridges other than road bridges can be efficiently constructed. One example of a precast concrete structure is a road bridge, and in this form, even if the precast concrete members are the deck members that form the road bridge, the precast segment method can be applied to the construction of the road bridge, rather than the conventional method of casting concrete in place.Then, when manufacturing the deck members, the gable formwork manufactured by the manufacturing method using the match cast method of this embodiment is used.

[0011] Another aspect of the method for manufacturing a gable form for manufacturing a precast concrete member according to the present invention is to The method further includes a step C of performing heat curing while one side of each of the end formwork A 1 and the end formwork B 1 is abutted against each other.

[0012] According to this embodiment, by carrying out heat curing with one side surface of each of the end forms A 1 and B 1 abutting against each other, it is possible to solve the problem that the joint end surfaces of both end forms become misaligned due to shrinkage deformation after production. Here, in step C, heat curing is preferable, but simple curing may be carried out instead of heat curing. Here, heated curing includes steam curing, and is a type of curing that is applied when manufacturing the gable formwork, a concrete component, in order to promote both the development of strength and shrinkage, such as autogenous shrinkage (shrinkage that occurs when the concrete loses water as it hardens due to the hydration reaction) and drying shrinkage (shrinkage that occurs when the water in the concrete escapes into the air). Therefore, the end form A1 and the end form B1 are manufactured, and heat curing is performed with one side of each of them abutting each other while the strength development and shrinkage of both are still insufficient. In this sense, the manufacture of the end form A1 in the process A and the manufacture of the end form B1 in the process B in this embodiment means that each end form is manufactured to a stage where the strength development and shrinkage are insufficient (including a stage where there is no strength development or shrinkage yet), and by performing heat curing in the process C, the strength development and shrinkage of both end form are sufficiently achieved. Since the end form B1 is manufactured using the end form A1, the process B of manufacturing the end form B1 and the process C of heat curing the end form A1 and the end form B1 are performed continuously. Here, the process B and the process C being performed continuously include not only the literally continuous process in time, but also the process being performed with a predetermined time between each process.

[0013] In another aspect of the method for producing a gable form for producing a precast concrete member according to the present invention, The process C is characterized in that, prior to heat curing, a compressive force is applied to the contact surfaces of both the end formwork A 1 and the end formwork B 1.

[0014] According to this embodiment, it is possible to ensure higher consistency between the abutting surfaces of both end forms A 1 and B 1 by applying compressive force (while clamping and restraining each other) during heat curing. For example, there is a method of applying PC steel bars, PC steel wires, or other PC steel members and performing heat curing while introducing a prestressing force equivalent to a compressive force into the PC steel members.

[0015] Another aspect of the method for manufacturing a gable form for manufacturing a precast concrete member according to the present invention is to A process D includes using the gable form A1 as a match-cast gable form to fabricate the gable form B2, using the gable form B1 as a match-cast gable form to fabricate the gable form A2, and carrying out heat curing with one side of the gable form A2 and the gable form B2 abutting against each other; The method is characterized in that multiple sets of the end formwork A 2 and the end formwork B 2 are produced by repeating the D process.

[0016] According to this embodiment, gable form A1 is used as a match-cast gable form to produce gable form B2, gable form B1 is used as a match-cast gable form to produce gable form A2, and process D, in which one side of gable form A2 and gable form B2 are abutted against each other and subjected to heat curing, is repeated to produce multiple sets of gable form A2 and gable form B2.By using each gable form unit consisting of gable form A2 and gable form B2, for example, simultaneously, it is possible to produce multiple precast concrete members at once which have consistent joint end faces. Here, if the unit of gable form A 1 and gable form B 1 that is produced first is designated as the first generation gable form unit as described above, the unit of gable form A 2 and gable form B 2 can be called the second generation gable form unit. Furthermore, gable form B2, which is manufactured as a match cast gable form from gable form A1, may be further manufactured as a match cast gable form to produce gable form A3, and gable form B3, which is manufactured as a match cast gable form from gable form B1, may be further manufactured as a match cast gable form to produce gable form B3, and multiple sets of gable form A3 and gable form B3 may be manufactured by repeating the process of carrying out heat curing with one side of both gable form A3 and gable form B3 abutting each other. In this case, the unit of gable form A3 and gable form B3 may be called a third generation gable form unit. This may be further developed to produce gable form units of the fourth generation or later.

[0017] Another aspect of the method for manufacturing a gable form for manufacturing a precast concrete member according to the present invention is to The method includes a process E in which the gable form A1 is used as a match-cast gable form to produce a gable form B2, the gable form B2 is used as a match-cast gable form to produce a gable form A2, and heat curing is performed with one side surface of the gable form A2 and the gable form B2 abutting against each other; The method is characterized in that multiple sets of the end formwork A 2 and the end formwork B 2 are produced by repeating the E process.

[0018] According to this embodiment, the end form A1 is used as the match cast end form to produce the end form B2, the end form B2 is used as the match cast end form to produce the end form A2, and the end form A2 and the end form B2 are abutted against each other at one side in the state of heat supply curing by repeating the process E to produce multiple sets of the end form A2 and the end form B2. By using each end form unit consisting of the end form A2 and the end form B2 at the same time, for example, it is possible to produce multiple precast concrete members with mutually consistent joint end faces at one time. In other words, this embodiment is another embodiment of the method for producing the second generation end form unit, which is different from the method for producing the second generation end form unit already described. Here, in the process E, heat supply curing is preferable, but simple curing may be performed instead of heat supply curing.

[0019] In another aspect of the method for producing a gable form for producing a precast concrete member according to the present invention, The steps D and E are characterized in that, prior to heat curing, compressive force is applied to the contact surfaces of both the end formwork A 2 and the end formwork B 2.

[0020] According to this embodiment, even in the manufacturing method for the second-generation gable form unit, by applying compressive force to the abutting surfaces of both gable form A 2 and gable form B 2 while performing heat curing, it is possible to ensure even higher integrity between the abutting surfaces of both the abutting gable formworks.

[0021] In another aspect of the method for producing a gable form for producing a precast concrete member according to the present invention, The gable formwork is characterized in that it is made of fiber-reinforced concrete.

[0022] According to this embodiment, since the gable formwork is made of fiber-reinforced concrete, it is possible to produce a gable formwork that has strength and rigidity, and therefore it is possible to reuse the gable formwork multiple times without damage such as chipped corners or cracks. Here, fiber-reinforced concrete includes concrete mixed with various fiber materials such as carbon fiber and glass fiber. Furthermore, by using high-strength concrete, the strength and rigidity of the gable formwork can be further increased. This high-strength concrete has a design standard strength of 50 N / mm 2 ~100N / mm 2 The concrete used has a design strength of 100N / mm 2 ~200N / mm 2 In this case, ultra-high strength fiber reinforced concrete or the like is used as the forming material.

[0023] In addition, one aspect of the method for producing a precast concrete member according to the present invention is to The present invention is characterized in that a plurality of the precast concrete members are manufactured using the end form manufactured by the method for manufacturing the end form for manufacturing the precast concrete members.

[0024] According to this aspect, by using multiple gable formwork units consisting of two gable formworks manufactured by the manufacturing method of the present invention, for example by using them simultaneously, it is possible to manufacture multiple precast concrete members at once, each having a matching joint end surface. Effect of the Invention

[0025] According to the present invention's method for manufacturing end formwork for producing precast concrete members and method for manufacturing precast concrete members, when producing precast concrete members for precast concrete structures formed by connecting a plurality of precast concrete members, production efficiency is good, a large work space is not required, and consistency of the joint end faces of the precast concrete members can be ensured. [Brief description of the drawings]

[0026] [Figure 1] FIG. 2 is a process diagram showing an example of a method for producing a gable formwork for producing precast concrete members in accordance with the first embodiment, illustrating process A. [Diagram 2] This figure shows end formwork A1 produced in process A, which is insufficient in terms of strength development and shrinkage, and also shows end formwork A1 produced in process C, which has sufficient strength development and shrinkage. [Diagram 3] FIG. 2 is a process diagram showing an example of a method for manufacturing a gable formwork following FIG. 1, and is a diagram explaining process B. [Figure 4] This figure shows end formwork B1 produced in process B, which is insufficient in terms of strength development and shrinkage, and also shows end formwork B1 produced in process C, which has sufficient strength development and shrinkage. [Diagram 5] 5 is a process diagram showing an example of a method for manufacturing a gable formwork following FIG. 3, and is a diagram explaining process C. FIG. [Figure 6] FIG. 11 is a process diagram showing an example of a method for producing a gable formwork for producing precast concrete members in accordance with the second embodiment, illustrating process D. [Figure 7] FIG. 11 is a process diagram showing an example of a method for producing a gable formwork for producing precast concrete members in accordance with the third embodiment, illustrating process E. [Figure 8] This figure shows the state in which heat curing is being performed while applying compressive force to the abutting surfaces of the gable formwork in steps D and E. [Figure 9] 1A to 1C are diagrams illustrating an example of a method for manufacturing a precast concrete member according to an embodiment of the present invention. [Figure 10] FIG. 2 is a perspective view of an example of a manufactured precast concrete member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, the method for manufacturing the end form for manufacturing the precast concrete member according to each embodiment and the method for manufacturing the precast concrete member according to each embodiment will be described with reference to the attached drawings. Note that in this specification and the drawings, the same reference numerals may be used to designate substantially the same components, and redundant description may be omitted.

[0028] [Method of manufacturing end formwork for manufacturing precast concrete members according to the first embodiment] First, an example of a method for manufacturing a gable form for manufacturing a precast concrete member according to the first embodiment will be described with reference to Figs. 1 to 5. Here, Figs. 1, 3, and 5 are process diagrams showing an example of a method for manufacturing a gable form for manufacturing a precast concrete member according to the first embodiment, and are diagrams explaining processes A, B, and C. Also, Fig. 2 is a diagram showing a gable form A 1 manufactured in process A in a state where strength development and shrinkage are insufficient, and a diagram showing a gable form A 1 manufactured in process C in which strength development and shrinkage are sufficient. Furthermore, Fig. 4 is a diagram showing a gable form B 1 manufactured in process B in a state where strength development and shrinkage are insufficient, and a diagram showing a gable form B 1 manufactured in process C in which strength development and shrinkage are sufficient. In the example shown in Fig. 1, etc., a method for manufacturing a gable form by a match cast method in a factory F is described, but the gable form may be manufactured at a site yard.

[0029] The factory F is equipped with steam piping P for steam curing (an example of heat supply curing) that leads to the boiler B, and by carrying out steam curing during the manufacturing process of the end formwork, it is possible to promote strength development and shrinkage and shorten the manufacturing time. In the illustrated example, the interior of the factory F is shown filled with steam, but a curing tank for steam curing may be provided within the factory F, and the steam curing of the end formwork may be carried out within the curing tank.

[0030] First, when manufacturing the end form A1 (10), the steel base molds K1 and K2 are installed with a gap corresponding to the width of the end form A1 (10) to be manufactured, and fresh concrete is poured into the space between them. On the end surface of one of the steel base molds K2, a recess K2a is provided for forming an engaging protrusion provided on the end surface of the end form A1 (10). Note that the engagement between the engaging protrusion and the engaging recess described below does not affect the surface accuracy of the formwork to be manufactured, so for example, the end surface of the end form A1 (10) may not have an engaging protrusion, and in this case, the recess K2a in the illustrated example is not necessary. Here, there may be a gap between the overlapping surfaces of the engaging protrusion and the engaging recess.

[0031] Ordinary concrete may be used for the concrete forming the gable form A1 (10), but fiber-reinforced concrete is used to prevent cracks and chipped corners and to allow the gable form to be reused multiple times. More preferably, fiber-reinforced high-strength concrete in which fiber material is mixed into high-strength concrete is used, and even more preferably, ultra-high-strength fiber-reinforced concrete in which fiber material is mixed into ultra-high-strength concrete. In the illustrated example, a case will be described in which ultra-high-strength fiber-reinforced concrete is used as the forming material.

[0032] In Figure 1, fresh ultra-high strength fiber reinforced concrete is poured between the steel base molds K1 and K2, and then steam is supplied in the X1 direction via steam pipe P for primary curing. Ultra-high strength fiber reinforced concrete uses more water reducing agent than normal concrete, ensuring high fluidity but slowing down setting, so setting and hydration reactions are promoted by steam curing at around 40°C, for example. Note that during peak summer when the outside temperature is high, there is no need for steam curing at around 40°C, making this primary curing unnecessary.

[0033] The primary curing allows the ultra-high-strength fiber-reinforced concrete to slowly develop strength and shrink (autogenous shrinkage and drying shrinkage), but by demolding the steel base forms K1 and K2 during the primary curing, gable formwork A1 (10'), which has insufficient strength development and shrinkage, is produced.

[0034] As shown in FIG. 2, the demolded end form A 1 (10') has a plurality of engaging protrusions 12 on one side surface 11 thereof (this is step A).

[0035] Next, as shown in Figure 3, gable formwork A1 (10') is used as a match-cast gable formwork, and is installed with a gap equivalent to the width of gable formwork A1 (10') and gable formwork B1 (20) for which steel base mold K1 is planned to be fabricated, and fresh ultra-high-strength fiber-reinforced concrete is poured into the space between them, in the same way as when gable formwork A1 was fabricated.

[0036] In Figure 3, after fresh ultra-high strength fiber reinforced concrete is poured between the gable formwork A1 (10') and the steel base form K1, the first curing is performed by supplying steam in the X1 direction through the steam pipe P, just as when the gable formwork A1 (10') was made.

[0037] During the first curing, only the steel base form K1 is removed to produce the gable formwork B1 (20'), which is in a state where strength development and shrinkage are insufficient.

[0038] Figure 4 shows a schematic diagram of end form B 1 (20') with both end form A 1 (10') and the steel base mold K1 removed, and a plurality of engagement recesses 22 are formed at positions corresponding to the plurality of engagement protrusions 12 on the abutment surface 21 of end form B 1 (20'), which was abutting against one side surface 11 of end form A 1 (10') (this is process B).

[0039] Next, as shown in Figure 5, a compressive force P is applied in the X2 direction to the abutting surfaces 11, 21 of both the end formwork A 1 (10') and the end formwork B 1 (20') while steam is supplied in the X1 direction via the steam piping P, thereby performing secondary curing (an example of heat supply curing).

[0040] Here, the compressive force P is applied, for example, by installing multiple PC steel members (not shown) so as to penetrate end formwork A 1 (10') and end formwork B 1 (20') and introducing a predetermined prestress to the PC steel members.

[0041] The secondary curing is carried out in a high-temperature atmosphere, for example, at about 90° C., which is higher than the primary curing. In order to prevent heat shock caused by a sudden increase in temperature, the temperature is gradually increased, for example, by 15° C. over about 4 hours, until it finally reaches about 90° C. This steam curing at about 90° C. is maintained for about 24 hours, and then the temperature is lowered at a rate of about 5° C. over 1 hour.

[0042] The second curing allows the end formwork A1 (10') and end formwork B1 (20') to fully develop strength and shrink, and the end formwork A1 (10) and end formwork B1 (20) as shown in Figures 2 and 4 are produced (this is Process C).

[0043] In process C, steam curing (secondary curing) is performed with compressive force P applied to the contact surfaces 11, 21 of both end form A 1 (10') and end form B 1 (20'), so that end form A 1 (10) and end form B 1 (20) are manufactured with sufficient strength development and shrinkage, with the contact surfaces 11, 21 in high consistency with each other. In other words, there is no problem that the consistency of the joint end surfaces 11, 21 of both end form A 1 (10) and end form B 1 (20) will be lost later due to drying shrinkage, etc., of both end form A 1 (10) and end form B 1 (20) after manufacturing.

[0044] By carrying out steps A through C as described above, one unit of gable form A 1 (10) and gable form B 1 (20) that form a pair of opposing end faces of a precast concrete member is manufactured. By repeatedly carrying out steps A through C, multiple units of gable form A 1 (10) and gable form B 1 (20) are manufactured. For example, by using multiple units of gable form A 1 (10) and gable form B 1 (20) simultaneously, it is possible to manufacture multiple precast concrete members with good matching of joint end faces at once.

[0045] According to the manufacturing method of the illustrated example, after manufacturing end form A 1 (10), end form B 1 (20) is manufactured using this end form A 1 (10) as a match-cast end form, thereby manufacturing two end formworks 10, 20 having joint end faces 11, 21 that are highly compatible with each other, and these two end formworks 10, 20 can be installed at both ends and precast concrete members can be manufactured inside them.

[0046] Because these gable formworks 10, 20 are not the precast concrete members that form the precast concrete structure themselves, the reduced production efficiency that would occur if precast concrete members were produced in the order in which they are connected is eliminated, and because the gable formworks 10, 20 can be made of concrete members that are as thin as possible, as is clear from Figures 2 and 4, their installation does not require a large work space or excessive labor, which leads to a reduction in the production costs of the precast concrete members.

[0047] Furthermore, since the gable forms 10, 20 are made of concrete, they can be easily formed even if the shape of the end of the precast concrete member is complex.

[0048] [Method of manufacturing end formwork for manufacturing precast concrete members according to the second embodiment] Next, an example of a manufacturing method for the end form for producing precast concrete members according to the second embodiment will be described with reference to Figures 6 and 8. Here, Figure 6 is a process diagram showing an example of a manufacturing method for the end form for producing precast concrete members according to the second embodiment, and is a diagram explaining step D, and Figure 8 is a diagram showing a state in which a compressive force is applied to the contact surface of the end form in step D.

[0049] The method of manufacturing the gable form shown in Fig. 6 is a method of manufacturing the gable form B2 (30') by using the gable form A1 (10) manufactured by the manufacturing method of the first embodiment already described as a match cast gable form, pouring fresh ultra-high strength fiber reinforced concrete between the gable form A1 (10) and the steel base mold K1, and manufacturing the gable form B2 (30') by using the gable form B1 (20) as a match cast gable form, and pouring fresh ultra-high strength fiber reinforced concrete between the gable form B1 (20) and the steel base mold K1. In Fig. 6, the manufacture of the gable form B2 (30') and the gable form A2 (40') are shown in a single drawing, and when manufacturing the gable form A2 (40'), a gap is provided between the gable form B1 (20) and the steel base mold K1.

[0050] When making end formwork B2 (30') and end formwork A2 (40'), the first curing is carried out as shown in Figure 6 to promote the setting and hydration reaction of the fresh ultra-high-strength fiber-reinforced concrete.

[0051] Both end form B2 (30') and end form A2 (40') are insufficient in terms of strength development and shrinkage. Therefore, as shown in Figure 8, the abutting surfaces 31, 41 of end form B2 (30') and end form A2 (40') are abutted against each other, and steam is supplied in the X1 direction via steam pipe P while compressive force P is applied to both abutting surfaces 31, 41 in the X2 direction, thereby carrying out secondary curing. This allows end form A2 (40') and end form B2 (30') to fully develop strength and shrink, and end form A2 (40) and end form B2 (30) are produced (this is process D).

[0052] While the method for producing the gable formwork according to the first embodiment is a method for producing multiple units of gable formwork A1 (10) and gable formwork B1 (20), the method for producing the gable formwork according to the second embodiment is a method for producing gable formwork B2 (30) using gable formwork A1 (10) as a match cast gable formwork, and producing gable formwork A2 (40) using gable formwork B1 (20) as a match cast gable formwork. In other words, while the method for producing the gable formwork according to the first embodiment is a method for producing only the first generation gable formwork A1 (10) and gable formwork B1 (20) that are produced first, the method for producing the gable formwork according to the second embodiment is a method for producing the second generation gable formwork A2 (40) and gable formwork B2 (30) using the first generation gable formwork A1 (10) and gable formwork B1 (20) as match cast gable formworks.

[0053] Furthermore, during the manufacturing process of Gable Form B2 (30'), Gable Form A1 (10) will undergo primary curing, but Gable Form A1 (10) has already undergone secondary curing at a higher temperature during the manufacturing process. Therefore, even if Gable Form A1 (10) is used multiple times to manufacture multiple Gable Form B2 (30') and undergoes primary curing each time, there is no risk of Gable Form A1 (10) undergoing further drying shrinkage, etc., and the shape and dimensions can be maintained in a stable state. This also applies to Gable Form B1 (20), which undergoes primary curing during the manufacturing process of Gable Form A2 (40').

[0054] By repeatedly carrying out step D, multiple units of end form A 2 (40) and end form B 2 (30) are produced. For example, by using multiple units of end form A 2 (40) and end form B 2 (30) simultaneously, it is possible to produce multiple precast concrete members with good matching of the joint end faces at once.

[0055] Although not shown in the figures, gable form B2 (30) produced from gable form A1 (10) as a match cast gable form is further used as a match cast gable form to produce gable form A3 (not shown), and gable form A2 (40) produced from gable form B1 (20) as a match cast gable form is further used as a match cast gable form to produce gable form B3 (not shown). By repeating the process of abutting one side of gable form A3 and gable form B3 against each other and performing heat curing, multiple sets of third generation gable form A3 and gable form B3 can be produced, or this can be further developed to produce fourth generation or later gable form units.

[0056] [Method of manufacturing end formwork for manufacturing precast concrete members according to the third embodiment] Next, an example of a method for manufacturing a gable form for producing precast concrete members according to the third embodiment will be described with reference to Figures 7 and 8. Here, Figure 7 is a process diagram showing an example of a method for manufacturing a gable form for producing precast concrete members according to the third embodiment, and is a diagram explaining step E, and Figure 8 is a diagram showing a state in which a compressive force is being applied to the contact surface of the gable form in step E.

[0057] The manufacturing method of the gable formwork shown in Figures 7 and 8 is similar to the manufacturing method of the gable formwork of the second embodiment in that it produces second-generation gable formwork A 2 (40) and gable formwork B 2 (30), but differs in the specific manufacturing method.

[0058] Here, the end form A1 (10) manufactured by the manufacturing method of the first embodiment already described is used as a match cast end form, and fresh ultra-high strength fiber reinforced concrete is poured between the end form A1 (10) and the steel base mold K1 to manufacture the end form B2 (30'), and then the manufactured end form B2 (30') is used as a match cast end form to manufacture the end form A2 (40') by pouring fresh ultra-high strength fiber reinforced concrete between the end form B2 (30') and the steel base mold K1. In Fig. 7, the manufacture of the end form B2 (30') and the end form A2 (40') are shown in a single drawing, so that a gap is provided between the end form B2 (30') and the steel base mold K1 when manufacturing the end form A2 (40').

[0059] Following Figure 7, as shown in Figure 8, the abutting surfaces 31, 41 of end formwork B 2 (30') and end formwork A 2 (40') are abutted against each other, and a compressive force P is applied to both abutting surfaces 31, 41 in the X2 direction while steam is supplied in the X1 direction via steam piping P. This performs secondary curing, which allows end formwork A 2 (40') and end formwork B 2 (30') to fully develop strength and shrink, and end formwork A 2 (40) and end formwork B 2 (30) are produced (this is process E).

[0060] By repeatedly performing process E, multiple units of end formwork A 2 (40) and end formwork B 2 (30) are produced, and by using multiple units of end formwork A 2 (40) and end formwork B 2 (30) simultaneously, it is possible to produce multiple precast concrete components with good consistency of joint end surfaces at one time.

[0061] [Method of manufacturing precast concrete members according to the embodiment] Next, an example of a method for producing a precast concrete member according to the embodiment will be described with reference to Figures 9 and 10. Here, Figure 9 is a diagram for explaining an example of a method for producing a precast concrete member according to the embodiment, and Figure 10 is a perspective view of an example of a produced precast concrete member.

[0062] By using first-generation end form A1 (10) and end form B1 (20), or second-generation end form A2 (40) and end form B2 (30), and pouring fresh ultra-high-strength fiber-reinforced concrete between them, a precast concrete member 50, which is a precast deck for a road bridge made of ultra-high-strength fiber-reinforced concrete as shown in Figure 10, is produced. Note that precast concrete members may be made from ordinary concrete or high-strength concrete.

[0063] In this manufacturing method, a plurality of end form units each consisting of two first generation end form units 10, 20 or two second generation end form units 30, 40 manufactured by the manufacturing method according to each embodiment are prepared, and by using them simultaneously, it becomes possible to manufacture at once a plurality of precast concrete members 50 having matching joint end faces 51, 53. In the illustrated example, a plurality of engaging protrusions 52 are provided on one joint end face 51, and a plurality of engaging recesses 54 that engage with the respective engaging protrusions 52 are provided on the other joint end face 53.

[0064] Therefore, by applying the precast segment construction method, in which multiple precast decks 50 are connected to each other at the bridge site, the joint end faces are directly bonded together using adhesive, and the pieces are integrated using prestress, it becomes possible to efficiently construct a road bridge (not shown in the figure) (an example of a precast concrete structure).

[0065] Further considering ultra-high-strength fiber-reinforced concrete bridges, the conventional construction method is to provide cast-in-place ultra-high-strength fiber-reinforced concrete between precast decks (segments). The reason for this is as follows. Compared to ordinary concrete bridges, ultra-high-strength fiber-reinforced concrete bridges have an ultra-high-strength precast deck, which makes them extremely thin. Therefore, the compressive stress of the precast deck caused by prestressing is extremely high, about 4 to 10 times that of ordinary concrete bridges. Therefore, if the joint end faces of the precast decks are not consistent, stress concentration may occur only in the abutting parts when prestressing is applied, and this stress concentration may cause damage such as cracks in the precast decks.

[0066] In addition, the reason why the match-cast method is not used in the manufacture of ultra-high-strength fiber-reinforced concrete bridge components, as is the case with ordinary concrete bridges, is as follows: as mentioned above, primary and secondary curing is carried out in the component manufacturing process, but when precast concrete components manufactured using the match-cast method are used as gable forms, the hydration reaction of the cement may not progress completely if these precast concrete components are subjected to two primary curings, which may have an adverse effect on the final strength of the precast concrete components.

[0067] For these reasons, when erecting a bridge made of ultra-high-strength fiber-reinforced concrete, it is necessary to lay a filler section of ultra-high-strength fiber-reinforced concrete between the precast decks, but this leads to longer construction periods and higher construction costs compared to ordinary PC bridges.

[0068] In response to these various issues, a gable form made of ultra-high-strength fiber reinforced concrete is produced by the method for producing gable formwork in each of the above-mentioned embodiments, and then a precast deck slab made of ultra-high-strength fiber reinforced concrete is produced by the method for producing precast concrete components in accordance with the embodiments using this gable formwork. This ensures consistency between the joint end surfaces of the precast decks and eliminates the need for cast-in-place ultra-high-strength fiber reinforced concrete, making it possible to extend the construction period and prevent increases in construction costs.

[0069] In addition, the present invention is not limited to the configuration shown here, and may be implemented in other embodiments in which other components are combined with the configurations and the like of the above-mentioned embodiment. In this regard, the present invention may be modified within the scope of the gist of the present invention, and may be appropriately determined according to the application form. [Explanation of symbols]

[0070] 10, 10': End formwork A1 (end formwork) 11: Contact surface (joint end surface, one side) 12: Engagement convex part 20, 20': Gable formwork B1 (gable formwork) 21: Contact surface (joint end surface) 22: Engagement recess 30, 30': Gable formwork B2 (gable formwork) 31: Contact surface (joint end surface) 32: Engagement recess 40, 40': End formwork Type 2 (end formwork) 41: Contact surface (joint end surface) 42: Engagement convex part 50: Precast concrete components (precast floor slabs) 51,53: Joint end surface 52: Engagement convex part 54: Engagement recess F:Factory P: Steam piping B: Boiler K1, K2: Steel base type K2a: Recess

Claims

1. A method for manufacturing a gable form used in manufacturing a precast concrete structure by connecting a plurality of precast concrete members, comprising the steps of: Process A includes pouring concrete into the formwork to fabricate a gable formwork A1 having a first joint end surface; A process B of manufacturing a gable form B1 having a second joint end surface that matches the first joint end surface by using the gable form A1 as a match cast gable form; A method for manufacturing a gable formwork for producing precast concrete members, comprising step C of performing heat curing while the first joint end face and the second joint end face, which are abutting surfaces, are in abutting contact with each other.

2. A method for manufacturing end formwork for producing precast concrete members as described in claim 1, characterized in that in step C, compressive force is applied to the abutting surfaces of both end formwork A 1 and end formwork B 1 prior to heat curing.

3. The method includes a step D of fabricating a gable form B2 using the gable form A1 as a match-cast gable form, fabricating a gable form A2 using the gable form B1 as a match-cast gable form, and carrying out heat curing while the contact surfaces of the gable form A2 and the gable form B2 are in contact with each other; 3. A method for manufacturing a gable formwork for producing precast concrete members as described in claim 1 or 2, characterized in that multiple sets of the gable formwork A 2 and the gable formwork B 2 are manufactured by repeating the D process.

4. The method includes a step E of manufacturing a gable form B2 using the gable form A1 as a match-cast gable form, manufacturing a gable form A2 using the gable form B2 as a match-cast gable form, and carrying out heat curing with the contact surfaces of the gable form A2 and the gable form B2 in contact with each other, 3. A method for manufacturing a gable formwork for producing precast concrete members as described in claim 1 or 2, characterized in that multiple sets of the gable formwork A 2 and the gable formwork B 2 are manufactured by repeating the E process.

5. A method for manufacturing a gable form for producing precast concrete members as described in claim 3, characterized in that in step D, prior to heat curing, a compressive force is applied to the abutting surfaces of both the gable form A 2 and the gable form B 2.

6. A method for manufacturing end formwork for producing precast concrete members as described in claim 4, characterized in that in step E, compressive force is applied to the abutting surfaces of both end formwork A 2 and end formwork B 2 prior to heat curing.

7. 7. The method for manufacturing a gable form for producing a precast concrete member according to claim 1, wherein the gable form is made of fiber-reinforced concrete.

8. 8. A method for producing precast concrete members, comprising the steps of: producing a plurality of precast concrete members using a gable form produced by the method for producing a gable form for producing precast concrete members according to any one of claims 1 to 7.

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