JP2007009492A - Precast segment, end form for use in its manufacture, and manufacturing method and joining method for precast segment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precast segment capable of being manufactured with a high degree of accuracy in a short period. <P>SOLUTION: The plurality of precast segments 1 are joined together so as to constitute a long structure. Two end surfaces 1a and 1b, which are formed in the direction of joining the precast segments 1 together, are molded in such a shape that one end surface 1a corresponds to the other end surface 1b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a precast segment constituting a long structure such as a bridge, a buried tunnel or a tower-like structure such as a tower, a wife formwork suitable for manufacturing the precast segment, and a method for manufacturing the precast segment. And a joining method for joining adjacent precast segments using the precast segment.

  Conventionally, a precast segment method as disclosed in Patent Document 1 or the like is known as a method for constructing a bridge superstructure.

  In this precast segment construction method, for example, a plurality of precast segments having a width of 30 m, a length of 5 m, and a height of about 4 to 7 m are manufactured from prestressed concrete, reinforced concrete, or the like at a factory or a manufacturing yard.

  Then, the precast segments that have been manufactured are transported to the site and constructed in sequence by building a long bridge girder.

  At this time, if the joint surfaces between adjacent precast segments do not match, when prestress is introduced, local compressive stress is generated on the joint surface and the end surface is destroyed, or the prestress stress of the expected amount In order to prevent this from happening, it is impossible to secure the design strength, so the match cast method is adopted.

This match casting method uses the end face of the precast segment that was produced earlier as the end form of the new precast segment, and uses the end face of the precast segment that is actually joined, so the joint faces are perfectly matched. be able to.
JP 2000-290933 A

  However, in the conventional match cast method, the precast segment to be newly manufactured cannot be formed into an accurate shape unless the existing precast segment is installed at an accurate position. However, since the weight of the precast segment is large, the position is finely adjusted. Is difficult and requires a large moving device.

  Moreover, since the existing precast segments are used as the wife formwork, they must be manufactured one by one in order, and a plurality of precast segments cannot be manufactured at the same time.

  Furthermore, since the concrete used for the production of precast segments will shrink and dry shrinkage over time, it will be newly produced if the precast segment used as the wife formwork is not managed so that the curing period is constant. Variation occurs in the shape of the precast segment.

  Even if the precast segments that have been produced are damaged or malfunctions occur, the precast segments placed on both sides of the precast segments are drying and shrinking, so these precast segments can be used as wife molds. It is difficult to remanufacture.

  Accordingly, an object of the present invention is to provide a precast segment that can be manufactured with high accuracy and in a short period of time, a wife formwork used for manufacturing the precast segment, a method of manufacturing the precast segment, and a method of joining the precast segments.

  In order to achieve the above object, the present invention provides a precast segment constituting a long structure by joining a plurality of joints, wherein two end faces formed in the joining direction of the precast segment are one of the precast segments. It is the precast segment shape | molded in the shape where an end surface and the other end surface correspond.

  Moreover, it is the wife formwork used for manufacture of said precast segment, Comprising: The 1st wife formwork used for shaping | molding of said one end surface, and the 2nd wife formwork used for shaping | molding of said other end surface Is a wife mold frame formed of a molding material filled on both sides of a partition plate formed with an equal thickness.

  Here, a protrusion having a linear portion and an enlarged portion can be continuously provided in the vertical direction on the formwork surface of the wife formwork.

  Further, according to the present invention, the first wife mold and the second wife mold of the above-mentioned wife mold are installed at an interval, and a cement-based mixed material is placed between them to form a precast segment. Then, after the cementitious mixed material is hardened, the first wife formwork and the second wife formwork are removed from the mold, and the first wife formwork and the second wife formwork are again placed at intervals. The precast segment manufacturing method is characterized by being used for forming a new precast segment.

  In addition, the present invention produces a plurality of precast segments using the first wife mold and the second wife mold of the above-mentioned wife mold and adjoins when installing the precast segment on site. After arranging and fixing the prestressed segment between the adjacent precast segments, the end surface formed by the first wife mold of the precast segment and the end surface molded by the second wife mold are opposed to each other. The precast segment joining method is characterized in that a filler is filled and cured from a vertical hole between the precast segments formed by the protrusions.

Here, as the cementitious mixture material and the molding material, compressive strength 150 N / mm ² or more, flexural tensile strength 25 N / mm ² or more, the fiber reinforcement split Tensile strength with 10 N / mm ² or more mechanical properties Cementitious mixed materials can be used.

  Such a fiber reinforced cementitious mixed material is obtained by mixing a composition containing cement, aggregate particles having a maximum particle size of 2.5 mm or less, pozzolanic reactive particles, and a dispersant with water. It can be obtained by mixing 1 to 4% of the total volume of fibers having a diameter of 0.1 to 0.3 mm and a length of 10 to 30 mm in a cement matrix.

  The present invention configured as described above is a precast segment formed into a shape in which one end face and the other end face are matched.

  For this reason, a plurality of precast segments having the same shape can be manufactured at the same time, and the joining surfaces with the adjacent precast segments can be matched.

  In addition, by forming a pair of end molds that form the end faces in the joining direction of the precast segments with a partition plate formed with an equal thickness between them, a shape that matches the form surface (matching joining) is formed. Can do.

  Since such a wife formwork only uses a formwork surface, it is easy to reduce the weight and can be easily installed at an accurate position, so that a precast segment can be manufactured with high accuracy.

  Moreover, even if the curing of the precast segment is not completed completely, the demolded wife form can be used for the production of other precast segments, so that many precast segments can be produced in a short time.

  Furthermore, if a projection part continuous in the vertical direction is provided on the formwork surface of the end formwork, a continuous recess is formed on the end face of the precast segment formed by the end formwork. By making the end faces of the segments face each other, a vertical hole penetrating in the vertical direction is formed.

  When this longitudinal hole is filled with a filler and cured, the cured portion can serve as a shear key to transmit shear force between the precast segments.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view of a precast segment 1 that constitutes a girder structure spanned on a bridge pier such as a bridge or artificial ground.

  First, in terms of the configuration, the precast segment 1 of the present embodiment has an upper floor slab with a width protruding from this girder on a U-shaped girder in cross section composed of two webs and a lower floor slab that form side walls. It is provided integrally.

  The first end form 2A and the second end form 2B are installed on the two end faces formed in the joining direction of the precast segment 1, and the end faces are formed by the form faces 21 of these end forms 2A and 2B. (First end face 1a, second end face 1b, see FIG. 4) are formed.

  The precast segment 1 can be manufactured from prestressed concrete or reinforced concrete using a cement-based mixed material such as concrete.

  That is, in a space surrounded by a pair of wife formwork (first wife formwork 2A, second wife formwork 2B) and a formwork (not shown) installed to form the bottom and side surfaces, The precast segment 1 can be formed by placing a cement-based mixed material.

  In addition, as the cement-based mixed material, it can be manufactured using an ultra-high strength fiber-reinforced cement-based mixed material.

  This fiber reinforced cementitious mixed material mixes metal fibers into a cementitious matrix obtained by mixing a composition containing cement, aggregate particles, pozzolanic reactive particles, and a dispersant with water. To make.

  Here, an aggregate material such as cinnabar having a maximum particle size of 3.0 mm or less, preferably 2.5 mm or less is used for the aggregate particles. Further, as the pozzolanic reaction particles, those having a particle size of 15 μm or less are used. For example, silica fume or the like is used as a highly active pozzolanic reaction particle having a particle size of 0.01 to 0.5 μm, and fly ash or blast furnace slag is used as a low activity pozzolanic reaction particle having a particle size of 0.1 to 15 μm. To do. These pozzolanic reactive particles having different activities can be mixed or used alone. Further, at least one type of the dispersant is used in order to improve fluidity.

For the metal fiber, for example, a steel fiber having a diameter of about 0.1 to 0.3 mm and a length of about 10 to 30 mm and a tensile yield stress of 2600 to 2800 N / mm ² is used. Further, this steel fiber is mixed in an amount of about 1 to 4% of the total volume of the fiber-reinforced cementitious mixed material to be produced.

A member formed of the above-mentioned fiber-reinforced cement-based mixed material manufactured with such a blend has a compressive strength of 150 to 200 N / mm ² , a bending tensile strength of 25 to 45 N / mm ² , and a split tensile strength of 10 to 25 N. / Mm ² , water permeability is 4.0 × 10 ⁻¹⁷ cm / sec, salt diffusion coefficient is 0.0019 cm ² / year, and elastic modulus is 50 to 55 GPa.

  FIG. 2 shows a perspective view of the manufacturing process of the pair of wife molds 2A and 2B used for manufacturing such a precast segment 1.

  The pair of wife molds 2A and 2B are formed at the same time, and are partitioned in the approximate center of a space surrounded by a mold (not shown) that molds the outer surfaces of the wife molds 2A and 2B. The plate 3 is erected to bisect the internal space, and the space on both sides of the partition plate 3 is filled with a molding material and molded.

  The partition plate 3 is a plate material having a constant thickness, and the formwork surfaces 21 of the pair of wife molds 2A and 2B formed on both sides of the partition plate 3 have the partition plate 3 removed. For example, it is formed into a matching shape (matching joint surface).

  A polymer material such as resin or a cement-based mixed material such as concrete can be used as the molding material for the end frames 2A and 2B.

  It is desirable that the cementitious mixed material has a low water cement ratio in order to reduce the shrinkage, and in order to accurately shape the details, use a high fluidity concrete with a low water cement ratio and high fluidity. Is desirable.

  Furthermore, if the fiber reinforced cementitious mixed material is used as the cementitious mixed material, the member thickness can be reduced and the weight can be significantly reduced because of high strength.

  In particular, by curing at a curing temperature of 80 to 100 ° C. for 40 to 50 hours in the secondary curing, the drying shrinkage after curing can be reduced to zero, and the creep deformation can be extremely reduced.

  For this reason, if the fiber-reinforced cement-based mixed material is used as the molding material of the end molds 2A and 2B, the mold surface 21 will not be deformed depending on the time. 1 can be produced repeatedly.

  Protrusions 4 as shown in FIG. 3 are provided on the mold surface 21 of the end mold 2A (2B) thus molded.

  The protrusion 4 has a semi-cylindrical linear portion 41 and a truncated quadrangular pyramid-shaped enlarged portion 42 provided in the middle of the linear portion 41, and is arranged vertically so as to cut the formwork surface 21 vertically. It is provided continuously in the direction.

  In FIG. 3, the protrusions 4 provided on the two webs of the end form 2 </ b> A have three enlarged portions 42, 42, 42 in the middle of the linear portion 41, and are spaced apart in the vertical direction. It is provided.

  Further, each of the protrusions 4, 4 of the upper and lower flanges between the webs is provided with an enlarged portion 42 at approximately the center of the linear portion 41.

  Such a protrusion 4 is formed by forming a pair of wife molds 2A and 2B with the partition plate 3 interposed therebetween, and then providing a mold for the protrusion 4 on the mold surface 21 and pouring a molding material. be able to.

  Alternatively, the protrusions 4 may be manufactured separately and attached to the mold surface 21 via an adhesive such as an epoxy resin. Regardless of which method is used to provide the protrusions 4, the protrusions 4 are provided in the same shape at the same positions on the pair of wife molds 2 </ b> A and 2 </ b> B.

  Thus, by providing the protrusions 4 so as to cut the mold surface 21 vertically, concave portions that are continuous in the vertical direction are formed on the end surfaces 1a, 1b of the precast segment 1 formed by the end frames 2A, 2B. Can be formed.

  The protrusions 4 and 4 provided on the upper and lower flanges serve as recesses that allow the upper end surface to communicate with the upper edge of the hollow portion and the lower edge of the hollow portion to communicate with the lower end surface, respectively.

  Next, the manufacturing method of the precast segment 1 of this Embodiment is demonstrated.

  First, a plurality of sets of a pair of wife molds 2A and 2B are manufactured, and installed at intervals as shown in the plan view of FIG. In FIG. 4A, four sets of wife formwork 2A, 2B are used, but may be reused by reducing the number of sets.

  Further, in FIG. 4 (a), the molds other than the wife molds 2A and 2B are not shown, but other molds are also installed so as to have the desired side and bottom shapes, and are surrounded by the molds. Reinforcing bars are arranged in the space as needed, and precast segments 1,... Are manufactured by filling cement-based mixed materials such as concrete and fiber-reinforced cement-based mixed materials.

  Since it is necessary to manufacture the precast segments 1,... As many as the total length of the girder structure, the first wife mold 2A and the second wife mold 2B are demolded after the cementitious mixed material is cured. Then, the remaining precast segments 1,.

  Next, the joining method of the precast segment 1 of this Embodiment is demonstrated.

  Since the precast segments 1,... Produced as described above are formed in a shape in which the first end surface 1a and the second end surface 1b in the joining direction coincide with each other, the adjacent precast segments 1,. If the precast segments 1 and 1 face each other so that one of the first end faces 1a and the other one becomes the second end face 1b, matching matching can be performed (see FIG. 4B).

  Here, an adhesive such as an epoxy resin or an acrylic resin is applied to the end faces 1a and 1b of the precast segment 1, and the first end face 1a and the second end face 1b facing each other are bonded together, Prestress is introduced by tensioning the tension members 8,..., Such as PC steel wires, communicated over the precast segments 1,.

  By doing so, the space between the precast segments 1,... Is fixed and does not move. Therefore, the vertical holes 5 formed by the concave portions formed on the first end surface 1a and the second end surface 1b are filled from below or above. The material 7 is filled (see FIG. 5).

  The vertical hole 5 has a linear hole portion 51 and an enlarged hole portion 52, as shown in FIG.

  The linear hole portion 51 is formed by the linear portion 41 of the protruding portion 4, and the enlarged hole portion 52 is formed by the enlarged portion 42 of the protruding portion 4.

  Thus, if the plurality of longitudinal holes 5,... Provided with a space between the precast segments 1, 1 are filled with the filler 7,. The filling material 7 filled in is a shear key for transmitting a shear force between the precast segments 1 and 1.

  As the filler 7, a polymer material such as cement-based non-shrink mortar, resin mortar, epoxy resin, or the above-mentioned cement-based mixed material can be used.

  In particular, when the fiber-reinforced cement-based mixed material is used as the filler 7, high deformation rigidity and shear strength can be exhibited with respect to the shear force acting on the shear key.

  Next, the operation of the precast segment 1 and the end forms 2A and 2B of the present embodiment will be described.

  Since the precast segment 1 of the present invention configured as described above is formed in a shape in which the first end face 1a and the second end face 1b match, even if a plurality of precast segments 1,. The joint surfaces with the adjacent precast segments 1 and 1 can be matched (matching joint).

  For this reason, only a part of the end surface is in contact and local bonding compressive stress is not generated on the bonding surface, and the desired prestress can be introduced by contacting the end surfaces 1a and 1b evenly. it can.

  Further, the pair of end form frames 2A and 2B forming the end faces 1a and 1b in the joining direction of the precast segment 1 are formed by sandwiching the partition plate 3 formed to have an equal thickness, thereby forming the form face surfaces 21 and 21. The shape can be matched.

  Such wife molds 2A and 2B only use the mold surface, so if a high-strength molding material is used, it can be made into a thin and light member. Can be easily installed.

  Further, even if the curing of the precast segment 1 is not completely completed, the demolded wife molds 2A and 2B can be used for the production of other precast segments 1, and a plurality of wife molds 2A having the same shape are used. , 2B can be manufactured, so that many precast segments 1, ... can be manufactured in a short time.

  In addition, if the precast segment 1 is manufactured using the end forms 2A and 2B which are completely dried and contracted and thus hardly deform depending on time, what is done? It can be easily remanufactured even once.

  By the way, at the joint between the precast segments 1 and 1, it is necessary to transmit shearing force and torsional moment in addition to transmitting bending moment. This bending moment can be transmitted by introducing prestress between the precast segments 1 and 1, but in order to transmit the shearing force and the torsional moment, the adhesive 6 increases the frictional force between the end faces 1a and 1b. It is effective to provide a shear key.

  Therefore, if projections 4,... That are continuous in the vertical direction are provided on the mold surface 21, 21 of the end frame 2 A, 2 B, the end face of the precast segment 1 formed by the end frame 2 A, 2 B. A continuous recess is formed in 1a, 1b, and this recess becomes a vertical hole 5, penetrating in the vertical direction by making the end faces 1a, 1b of adjacent precast segments 1, 1 face each other.

  When the vertical holes 5 are filled with the filler 7 and hardened, the hardened portion can serve as a shear key to transmit a shear force between the precast segments 1 and 1.

  Further, if the shear key is formed by the filler 7 filled after the precast segments 1 and 1 are brought into contact with each other in this way, the shear key can be made to completely match the shape of the enlarged hole portion 52. Therefore, local compression stress is not generated in the fitting portion due to a manufacturing error as in the conventional method in which unevenness is provided on the end face in advance and the fitting portion is not damaged.

  Hereinafter, Example 1 of the above-described embodiment will be described. The description of the same or equivalent parts as those described in the above embodiment will be given the same reference numerals.

  In the first embodiment, a case where a girder structure whose cross section changes in the middle is constructed by the precast segment 1 will be described.

  The bridge girder has a cross-section girder structure in which the cross section near the pier is large, and the cross section gradually decreases as it approaches the center between the piers.

  Thus, even the precast segment 1 constituting the girder structure whose cross section changes can be easily manufactured by using the end form frame 12 as shown in FIG.

  The end form 12 is an end form 12 that is formed so as to include all cross sections, and the end face 121 is the other end form that is paired as described in the above embodiment. (Not shown) is formed into a shape that can be matched and joined.

  The end form 12 is used by drawing the shape of the end face of the precast segment 1 of various sizes (the first form surface 121A and the second form surface 121B) on the form surface 121. If the position where the shape of the end surface is drawn by the pair of end forms 12 does not match, matching joining cannot be performed.

  Therefore, in order to easily perform this positioning, a plurality of pins are passed through a partition plate (not shown) used for manufacturing the end frame 12 so as to protrude from both sides, and the partition plate is molded by this partition plate. The reference points 13a,... Are provided on the formwork surface 121 of the wife formwork 12.

  Then, if the L-shaped reference line 13 is drawn by connecting the reference points 13a,..., The reference line 13 can be drawn at the same position by the pair of end frames 12, If the first mold surface 121A and the second mold surface 121B are drawn on the basis of the reference line 13, the end surfaces in the joining direction of the precast segments 1 can be formed into a matching shape.

  In addition, the end form frame 12 having such a configuration can cope with any shape of the end face, so that it can be used repeatedly and is economical.

  Other configurations and functions and effects are substantially the same as those in the above-described embodiment, and thus description thereof is omitted.

  Hereinafter, Example 2 of the above-described embodiment will be described. The description of the same or equivalent parts as those described in the above embodiment will be given the same reference numerals.

  In the second embodiment, a case where the precast segments 15 and 15 are joined while being inclined will be described.

  Some bridge girder structures are constructed with an arched vertical gradient, and others are constructed in a curved shape in plan view. In addition, a curved tunnel may be constructed even in a submerged tunnel.

  In such a case, it is necessary to provide a joining angle (bending angle) between the precast segments 15 and 15, and the manufacturing method and joining method of such a precast segment 15 will be described with reference to the plan view shown in FIG. explain.

  First, in order to construct a joint portion having a joint angle 2θ, when the precast segment 15 is manufactured, the first wife mold 16A and the second wife mold 16B are respectively inclined by θ with respect to the bridge axis orthogonal direction. .

  Here, the first wife form 16A and the second wife form 16B can be manufactured by the same method as in the above embodiment.

  Further, in FIG. 8A, the first end surface 15 a and the second end surface 15 b facing each other of the adjacent precast segments 15 and 15 are illustrated, but such first end surfaces are provided on both sides of one precast segment 15. 15a and the 2nd end surface 15b are shape | molded.

  The first end face 15a and the second end face 15b of the precast segments 15 and 15 manufactured by inclining the pair of the first wife form 16A and the second wife form 16B, which become matching joints, by the same angle θ are as follows. Since the shapes match, if they are joined facing each other, a joined portion having a joined angle 2θ as shown in FIG. 8B can be constructed.

  As described above, since the end forms 16A and 16B of the present invention are lightweight, they can be easily tilted to a predetermined angle. Therefore, even when there is a folding angle between the precast segments 15 and 15, it is easy and highly accurate. A joint can be constructed.

  Other configurations and functions and effects are substantially the same as those of the above-described embodiment or Example 1, and thus description thereof is omitted.

  Although the best embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention are possible. Are included in the present invention.

  For example, in the above-described embodiment and examples, the bridge girder structure has been described as an example of a long structure, but the present invention is not limited to this, and tower structures such as submerged tunnels and towers are used. The present invention can also be applied to a precast segment constituting the long structure.

  Moreover, the number and position of the projections 4 provided on the mold surface 21 of the wife molds 2A and 2B shown in the above embodiment and the number and shape of the enlarged parts 42 are examples. However, the present invention is not limited to this, and can be arbitrarily set.

  Further, depending on the strength of the adhesive 6 and the size of the prestress to be introduced, it is not necessary to form the vertical holes 5 by the protrusions 4, and other forms of shear keys may be applied or the shear keys may be omitted. You can also

  Moreover, although Example 1 demonstrated the case where the end surface of a some shape was shape | molded by one type of end form 12, it is not limited to this, Precast segment 1 of the kind demonstrated in the said embodiment The end forms 1a and 1b can also be manufactured each time the cross section changes, with the wife molds 2A and 2B adapted to the shape of the end faces 1a and 1b. In this case, it becomes easy to install the mold used for molding the side surfaces other than the wife molds 2A and 2B.

It is the perspective view which showed the precast segment and wife formwork of the best embodiment of this invention. It is the perspective view which showed the structure of the manufacturing process of a pair of wife formwork. It is the perspective view which showed the structure of the wife formwork which provided the projection part in the formwork surface. (A) is a top view which showed the manufacture process of a some precast segment, (b) is a top view explaining the state which made the some precast segment contact | abut. It is a top view explaining the structure of the junction part between precast segments. It is sectional drawing of the AA line direction of FIG. It is a perspective view explaining the structure of the wife formwork of Example 1. FIG. (A) is a top view explaining the structure of the edge part of the precast segment of Example 2, (b) is a top view explaining the structure of the junction part of the precast segment which has a fold angle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Precast segment 1a 1st end surface 1b 2nd end surface 2A 1st end formwork 2B 2nd end formwork 21 Formwork surface 3 Partition plate 4 Projection part 41 Linear part 42 Enlarged part 5 Vertical hole 7 Filler 12 End formwork 121 Formwork surface 121A First formwork surface 121B Second formwork surface 15 Precast segment 15a First end face 15b Second end face 16A First end formwork 16B Second end formwork

Claims (7)

A precast segment constituting a long structure by being joined together,
2. A precast segment, wherein two end faces formed in a joining direction of the precast segment are formed in a shape in which one end face and the other end face coincide with each other. A wife formwork used in the production of the precast segment according to claim 1,
The first end formwork used for forming the one end face and the second end formwork used for forming the other end face were filled on both sides of the partition plate formed to have the same thickness. A wife formwork characterized by being formed of a molding material.   The wife formwork according to claim 2, wherein a protrusion having a linear part and an enlarged part is continuously provided in a vertical direction on a formwork surface of the wife formwork.   The first formwork and the second formwork of the wife formwork according to claim 2 or 3 are placed at an interval, and a cement-based mixed material is placed between them to form a precast segment. Then, after the cementitious mixed material is hardened, the first wife formwork and the second wife formwork are removed from the mold, and the first wife formwork and the second wife formwork are again placed at intervals. And a method for producing a precast segment, which is used for forming a new precast segment.   When a plurality of precast segments are manufactured using the first and second wife molds of the wife mold according to claim 3, and the precast segments are installed on site, adjacent precast segments The protrusions are arranged so that the end face formed by the first end mold and the end face formed by the second end form are opposed to each other, and prestressed is introduced and fixed between adjacent precast segments. A precast segment joining method, comprising filling a filler from a vertical hole between precast segments formed by the portion and curing the filler. As the cementitious mix materials, compressive strength 150 N / mm ² or more, flexural tensile strength 25 N / mm ² or more, split Tensile strength using a fiber reinforced cementitious composite material with 10 N / mm ² or more mechanical properties The method for producing a precast segment according to claim 4. As the forming material, compressive strength 150 N / mm ² or more, flexural tensile strength 25 N / mm ² or more, the use of fiber-reinforced cement mixture material split Tensile strength with 10 N / mm ² or more mechanical properties The wife formwork of Claim 2 or 3 characterized by the above-mentioned.

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