JP2004108008A - Joint structure and joining method for cement board for permanent form - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply ensure fixed joining strength without excessively taking labor and time. <P>SOLUTION: In a joint structure, plate-shaped cement boards 10 and 10a are arranged adjacently in the vertical and horizontal directions, and a joining section between a pair of the adjacent cement boards 10 and 10a is bonded and fixed through an adhesive 12. The adhesive 12 is composed of the mixture of an epoxy-resin base compound, a curing agent and an inorganic granular substance such as quartz sand. A space section 14 expanded towards the outside is formed to the joining section of a pair of the adjacently installed cement boards 10 and 10a, the inside of the space section 14 is filled with the adhesive 12 composed of the mixture and the cement boards 10 and 10a are bonded and fixed by curing the filled adhesive 12. <P>COPYRIGHT: (C)2004,JPO

Description

【００４９】
引張り試験には、図９に示した供試体と同様なものを作製し、そこから切り出して試験体とした。引張り方法は、接着面を中央とし、幅４０ｍｍ、全長３００ｍｍの試験体を、直接オートグラフのチャックで挟み込んで、試験速度０．３ｍｍ／ｍｉｎ、チャック間距離２００ｍｍで試験を行った。試験結果を以下の表２に示している。
【表２】

【００５０】
この引張り試験では、破壊は、全て接着面で界面剥離が発生した。この試験結果から明らかなように、拡開角度が４５°の供試体Ａと、拡開角度が３０°の供試体Ｂとでは、不充填部の影響などによるバラツキが大きく、引張り強度もかなり低い値になっている。これに対して、拡開角度が６０°の供試体Ｃでは、不充填部が目視観察では、認められず、引張り強度は、母材引張り強度の約半分である７．１５Ｎ／ｍｍ２となっていた。
曲げ試験は、図１０に示す方法により行った。この試験では、等曲げ区間を有する二点載荷で、支持間距離を８００ｍｍとした。試験結果を以下の表３に示している。
【表３】

【００５１】
この曲げ試験では、破壊は、全て接着面での界面剥離であった。特に、この試験結果においては、拡開角度が４５°の供試体Ａと、拡開角度が３０°の供試体Ｂとは、拡開の角度がない方、つまり、９０°側の界面で、母材（セメントボード）を取込むような形態での破壊が発生していた。
【００５２】
拡開角度が６０°の供試体Ｃでは、接着面の破壊において、他の供試体よりも、より多くの母材を取込むようにして破壊していて、母材破断に近い形になっていた。
なお、供試体Ｃでは、６０−３だけが、拡開部分と反対側の面に接着剤が間乱していて、その影響で他の供試体６０−１，６０−２よりも最大強度が大きくなったものと推察される。
また、破断面の状況を写真撮影して観察したところ、供試体の一部に接着剤の見充填部分が観察され、この未充填部分は、拡開角度が小さいほど、充填不足が大きくなる傾向があった。
【００５３】
なお、図６〜図８に示した実施例では、空間部１４ｃ内に充填する接着剤１２を２度に分けて行う場合を例示したが、コンクリートＣを打設する前に、空間部１４ｃ内に全量を充填しても良い。
【００５４】
【発明の効果】
以上、詳細に説明したように、本発明にかかる永久型枠用セメントボードの接合構造および接合方法によれば、手間や時間を余りかけることなく、一定の接合強度が比較的簡単に確保され、接合部の汚れも防止することができる。
【図面の簡単な説明】
【図１】本発明にかかる永久型枠用セメントボードの接合構造の第１実施例を示す要部断面図である。
【図２】図１に示した接合構造で用いるセメントボードの平面図である。
【図３】本発明にかかる接合方法で用いるセメントボードの端部説明図である。
【図４】本発明にかかる永久型枠用セメントボードの接合構造の第２実施例を示す要部断面図である。
【図５】本発明にかかる永久型枠用セメントボードの接合構造の第３実施例を示す要部断面図である。
【図６】本発明にかかる接合方法の他の実施例を示す初期工程の断面説明図である。
【図７】図６に引き続いて行われる工程の断面説明図である。
【図８】図７に引き続いて行われる工程の断面説明図である。
【図９】本発明の作用効果を確認するために行った試験に用いた供試体の説明図である。
【図１０】本発明の作用効果を確認するために行った曲げ試験の試験方法の説明図である。
【符号の説明】
１０，１０ａ，１０ｂ，１０ｃ　　　　　セメントボード
１２　　　　　接着剤
１４　　　　　空間部
１６　　　　　粘着性シート
１８　　　　　切断面
２０　　　　　垂直面[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a joining structure and a joining method for a cement board for permanent formwork.
[0002]
[Prior art]
The cement board, which is buried on the surface of a concrete structure and is also used as a formwork for concrete casting, is unknown as to the known literature, but is used for actual construction sites, for example, for seismic reinforcement of existing piers, etc. Tend to be.
[0003]
The cement board used for such an application is also called a permanent form board because it is also used as a form, for example, cement-based, high-strength vinylon fiber as a reinforcing fiber, dispersed and mixed. The manufacturing method of this thing is manufactured by press molding or extrusion molding, and when manufactured by either method, compared to general concrete,
[0004]
It has a compression strength of at least 2 times and a strain resistance of at least 10 times.
When such a cement board is used as a permanent mold, a flat plate formed in a predetermined size is arranged adjacently in front, rear, left and right directions, and the adjacent cement boards are joined. When joining such boards, if the thickness of the boards is thin, use a joint plate that straddles between the two boards, and bond and fix the joint plate to the back side of the joint of each cement board. I was
However, such a cement board joining method has a technical problem described below.
[0005]
[Problems to be solved by the invention]
That is, in the joining method in which the joint plate is adhered and fixed with an adhesive, a liquid adhesive is applied, and the liquid is appropriately dried, and then bonded together. However, it is difficult to control this time, and a constant adhesive strength is required. It was difficult to secure.
In addition, when the joint board is bonded to the joint, if the joint board is not pressed for a while, a complete adhesion state cannot be obtained, and a considerable amount of manpower and time is required in actual work.
In addition, if the joints are bent during construction, the joint board may peel off, and it is necessary to apply adhesive to the joint surfaces of the cement board. For example, there has been a problem that the adhesive drips from the joint surface and the joint part becomes dirty.
[0006]
The present invention has been made in view of such a problem, and an object of the present invention is to ensure a constant joining strength relatively easily without taking much labor and time, and to achieve a joint portion. An object of the present invention is to provide a joining structure and a joining method of a cement board for a permanent form that can prevent dirt.
[0007]
[Means for Solving the Problems]
Means for Solving the Problems To achieve the above object, the present invention provides a permanent form in which a flat cement board is arranged vertically and horizontally adjacent to each other, and a joint between a pair of adjacent cement boats is fixed with an adhesive. In the joint structure of the cement board for use, the adhesive is composed of a mixture of an epoxy resin main agent, a hardening agent, and inorganic particulate matter such as silica sand, and a space portion that expands outward to the joint portion. By forming the mixture, filling the space into the mixture, and curing the mixture, the adjacent cement boards were bonded and fixed.
[0008]
According to the joint structure of the cement board for permanent form formed as described above, the joint portion between the pair of adjacent cement boats is formed with a space portion that expands outward, and the epoxy resin is formed in this space portion. Filling and hardening a mixture of the main agent, hardener, and inorganic particulate matter such as silica sand, adhesively fixes between adjacent cement boards. There is no need for control and there is no need to hold down, and a constant adhesive strength according to the composition of the mixture can be obtained.
[0009]
Also, the adhesive to be filled into the space is a mixture of an epoxy resin base material, a curing agent, and inorganic particulates such as silica sand, so that the addition of the inorganic particulates results in a putty or clay-like liquid adhesive. As described above, there is no danger of fouling the joints, the space can be easily filled, the handling is easy, and the finish is beautiful.
[0010]
In this case, in particular, when silica sand is used for the inorganic particulate matter, the silica sand is a very chemically stable substance and is in the form of fine sand. By mixing this, the durability of the adhesive is improved. I can do it.
[0011]
The inorganic particulate matter such as the silica sand may be mixed in the mixture in an amount of 30 to 50% by weight.
The space may be formed by forming a cut surface having an inclination angle of 30 to 45 ° on one contact end surface of the cement board to be installed adjacently and abutting the cut surface on the end surface of the other cement board. it can.
The cut surface may be formed on both of the cement boards installed adjacent to each other, and the space may be formed so as to straddle between the cement boards. The opening angle of the space may be 60 °.
[0012]
Further, the present invention provides a method of joining a cement board when a flat cement board is arranged vertically and horizontally adjacent to each other, and concrete is cast after the rear face, and the cement board is used as a permanent form. Forming a space that expands outward at the joint, filling the space with a mixture of an epoxy resin main agent, a curing agent, and an inorganic particulate material such as silica sand, and curing the mixture. Adhesive fixing was performed between adjacent cement boards.
According to the cementing method for a permanent form cement board configured as described above, the same operation and effect as the above-described joining structure can be obtained.
[0013]
The mixture may be partially filled in the space before casting the concrete to ensure water-stopping, and after the concrete has been cast, the remaining portion may be filled in the space.
The partial filling amount may be an amount corresponding to approximately half the height of the space, or approximately half the total filling amount.
The mixture can be filled in the space after sticking an adhesive sheet to the back side of the space and placing the concrete.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 show a first embodiment of a joining structure and a joining method of a cement board for a permanent form according to the present invention.
[0015]
FIG. 1 is a cross-sectional view showing a cement board joining structure of the present embodiment. In the joint structure shown in FIG. 1, rectangular cement boards 10 and 10a each having a predetermined length and width and having a predetermined thickness are arranged adjacently in the vertical and horizontal directions, and a pair of cement boats 10 adjacent to each other are arranged. , 10a are bonded and fixed with an adhesive 12 therebetween.
[0016]
In this case, the adhesive 12 is composed of a mixture of an epoxy resin main agent, a curing agent, and inorganic particles such as silica sand and glass powder. In order to obtain the adhesive 12 composed of such a mixture, an epoxy-based adhesive composed of an epoxy resin base material and a curing agent is, for example, Seakadur W (adhesive for precast concrete blocks, manufactured by Nippon Sika Co., Ltd., trade name: Is commercially available, and can be easily obtained by adding and mixing a predetermined amount of inorganic particulate matter such as silica sand.
[0017]
The inorganic particulate matter such as silica sand to be added to the adhesive 12 can be added to the mixture at a ratio of 30 to 50% by weight. In this case, if it is less than 30% of the lower limit, the viscosity of the mixture is insufficiently reduced, and the mixture may sag when filling into the space 14 described later. On the other hand, if it exceeds 50% of the upper limit, the decrease in viscosity becomes too large, and the filling property into the space 14 decreases.
[0018]
On the other hand, at the joint between the pair of cement boards 10 and 10a disposed adjacent to each other, a space 14 expanding outward is formed, and the space 14 is formed of the mixture described above. The cement board 10, 10a is bonded and fixed by filling the filled adhesive 12 and curing the filled adhesive 12.
[0019]
In the case of the present embodiment, the space portion 14 is not provided over the entire length of the cement boards 10 and 10a in the thickness direction, and the lower end side is closed by the contact between the cement boards 10 and 10a. ing. An adhesive sheet 16 is attached to the back side of the closed portion.
[0020]
Next, a description will be given of a cement board joining method for obtaining such a joint structure. The cement boards 10, 10a used for bonding are formed in a substantially rectangular shape as shown in a plan view in FIG. 2, and are fiber-reinforced high-toughness boards containing cement as a main component and high-strength vinylon fibers as reinforcing fibers. It is composed of
[0021]
Such a cement board 10, 10a can be used also as a form plate when forming a concrete structure. In this case, the cement boards 10, 10a are formed so as to surround the outer periphery of the structure to be constructed. Is installed, and concrete C is cast on the back side, and when the strength of the concrete C is developed, the cement boards 10, 10a are integrated with the outer surface of the structure.
[0022]
As the fiber-reinforced high-toughness cement board, for example, a board having a maximum thickness of 10 mm or less, a bending strength of 30 MPa or more, a span of 18 cm, and a maximum deflection of 25 mm or more can be used.
[0023]
The cement boards 10 and 10a used in the joining method of the present embodiment have ends of the joining portions as shown in FIG. That is, as shown in FIG. 3A, a cut surface 18 inclined at an angle of 45 ° is formed on the end surface of one cement board 10a. Although not shown, the cut surface 18 is formed on each of four sides of the cement board 10 to be joined.
[0024]
In the case of the present embodiment, the cut surface 18 is obtained by obliquely cutting the end surface of the cement board 10a so that the inclination angle is 45 °, and the tip of the inclined surface is in the thickness direction of the cement board 10a. Is formed so that it does not reach the edge of.
[0025]
That is, the cutting surface 18 extends downward at an angle of 45 ° from the upper end surface of the cement board 10a, and the tip of this inclined surface does not reach the lower end surface of the cement board 10a, and Ending upwards, the remaining portion is a vertical portion 19.
In the present embodiment, the vertical portion 19 is provided, but the vertical portion 19 is not always necessary, and may be formed so that the tip of the inclined surface reaches the edge in the thickness direction of the cement board 10a. it can.
[0026]
As shown in FIG. 3B, the end surface of the other cement board 10 to be joined is a vertical surface 20 which does not form the cut surface 18 and is orthogonal to the upper and lower main planes at 90 °.
When the end surfaces to be joined of the pair of cement boards 10 and 10a configured as described above are brought into contact with each other, as shown in FIG. 1, the cut surface 18 inclined at 45 ° is formed on one cement board 10a. The oblique side has a cross section of a right triangle with a 45 ° angle, the upper end is open, and a space 14 is formed which opens upward at an angle of 45 °.
[0027]
In this case, when the vertical surface 20 and the vertical portion 19 abut on each other, the lower end side of the space 14 is closed at the portion where the vertical surface 20 and the vertical portion 19 abut. When such a space portion 14 is formed between the cement boards 10 and 10a, then, in the case of the present embodiment, the adhesive sheet 16 is adhered to the back side of the cement boards 10 and 10a.
[0028]
The adhesive sheet 16 is affixed for waterproofing treatment when the concrete C is cast, and covers the lower end side of the space portion 14 so as to cover the cement board 10, 10a. It is arranged so as to straddle.
In addition, as such an adhesive sheet 16, for example, a rubber-like span seal (trade name, manufactured by Hayakawa Rubber Co., Ltd.) can be used.
[0029]
When the sticking of the adhesive sheet 16 is completed, concrete C is cast on the back side of the cement boards 10 and 10a. After the concrete C is cast, the space 12 is filled with an adhesive 12 made of a mixture to which inorganic particulate matter such as silica sand is added, and the adhesive 12 is hardened. Adhesion and fixing are performed, and the joining is completed.
[0030]
Now, according to the joining structure and the joining method of the cement board for a permanent form configured as described above, the space portion 14 that expands outward at the joining portion between the pair of adjacent cement boats 10 and 10a is formed. This space 14 is filled with a mixture (adhesive 12) of an epoxy resin main agent, a curing agent, and inorganic particulate matter such as silica sand, and is cured to form a space between adjacent cement boards 10 and 10a. Is fixed and adhered, so that it is not necessary to control the time until drying as in the case of applying a liquid adhesive, and it is not necessary to hold down the adhesive, and a constant adhesive strength according to the composition of the mixture can be obtained.
[0031]
Further, since the adhesive 12 to be filled in the space 14 is a mixture of an epoxy resin base material, a curing agent, and inorganic particulates such as silica sand, the adhesive 12 is putty or clay-like due to the addition of the inorganic particulates. There is no drip like an adhesive, and there is no danger of soiling the joint. In addition, the space 14 can be easily filled, the handling becomes easy, and the finish becomes clean.
In this case, in particular, when silica sand is used for the inorganic particulate matter, the silica sand is a very chemically stable substance and is in the form of fine sand. By mixing this, the durability of the adhesive is improved. I can do it.
[0032]
In addition, in the joining method of the present embodiment, the mixture (adhesive 12) is configured such that an adhesive sheet 16 is attached to the back side of the space 14 and the space 14 is filled after the concrete C is cast. Has adopted.
[0033]
According to such a configuration, the sticking of the cast concrete C and the outflow of moisture are prevented by the adhesive sheet 16, and the concrete C can be poured immediately after the boards 10, 10a are assembled. This is an effective method particularly in the case of rapid construction or when concrete is cast in the cold, when the strength of the adhesive 12 is low.
[0034]
FIG. 4 shows a second embodiment of the joining structure of the cement board for permanent form according to the present invention. The same reference numerals are given to the same or corresponding parts as in the above embodiment, and the description thereof will be omitted. In addition, only the characteristic points will be described below.
[0035]
In the embodiment shown in the figure, in the joint structure, the opening angle of the space 14b filled with the adhesive 12 is 30 °, which is different from the first embodiment. One cement board 10 to be joined is the same as that of the first embodiment, but the other cement board 10b is formed with a cut surface 18b having a tilt angle of 60 ° and a vertical portion 19b. .
When the end surfaces of the cement boards 10 and 10b to be joined are brought into contact with each other, the cut surface 18b formed on one cement board 10b and inclined at 60 ° forms a right-angled triangular cross section having a hypotenuse of 30 °. In the shape, a space portion 14b which is open at the upper end and is opened upward at an angle of 30 ° is formed.
[0036]
Then, the adhesive sheet 16 is adhered to the back side of the cement boards 10 and 10a, and thereafter, concrete C is cast on the back side of the boards 10 and 10b. Thereafter, silica sand or the like is placed in the space 14b. When the adhesive 12 made of a mixture to which the inorganic particulate matter is added is filled and the adhesive 12 is cured, the cement boards 10 and 10b are bonded and fixed, and the joining is completed.
The same effect as that of the above embodiment can be obtained by the joint structure of the cement board for a permanent form configured as described above.
[0037]
FIG. 5 shows a third embodiment of a cement board for permanent form according to the present invention, in which the same or corresponding parts as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted. In addition, only the characteristic points will be described below.
[0038]
In the embodiment shown in the figure, in the joint structure, the expansion angle of the space 14c filled with the adhesive 12 is 60 °, and the space 14c is formed so as to straddle the cement boards 10b, 10c. This is different from the first embodiment. One cement board 10b to be joined is the same as that of the second embodiment, but the other cement board 10c has a cut surface 18c having a tilt angle of 60 ° and a vertical portion 19c similarly to the board 10b. Are formed.
[0039]
When the end faces of the cement boards 10b and 10c to be joined are brought into contact with each other, the cut surfaces 18b and 18c formed on the cement boards 10b and 10c and inclined at 60 ° face each other, and the apex angle is reduced. The space 14c has a 60 ° equilateral triangular cross-sectional shape, an upper end opening, and an upwardly expanding 60 ° angle.
[0040]
Then, the adhesive sheet 16 is stuck on the back side of the cement boards 10b and 10c, and then concrete C is poured on the back side of the boards 10b and 10c. When the adhesive 12 made of a mixture to which the inorganic particulate matter is added is filled and the adhesive 12 is cured, the adhesive is fixed between the cement boards 10b and 10c, and the joining is completed.
[0041]
The same effect as that of the above embodiment can be obtained by the joint structure of the cement board for a permanent form configured as described above. The adhesive sheet 16 shown in the first to third embodiments is not always necessary when the space 12 is filled with the adhesive 12 before the concrete C is poured.
[0042]
6 to 8 show a second embodiment of the method for joining a cement board for a permanent form according to the present invention. The joining method shown in the figure is a joining method in the case of obtaining the joining structure of the third embodiment of the joining structure shown in FIG. 5 from which the adhesive sheet 16 is removed.
In the joining method of the present embodiment, similarly to the case shown in FIG. 5, both cement boards 10b and 10c to be joined have cut surfaces 18b and 18c having a tilt angle of 60 ° and vertical portions 19b and 19c. Are formed.
[0043]
When the end faces of the cement boards 10b and 10c to be joined are brought into contact with each other, the cut surfaces 18b and 18c formed on the cement boards 10b and 10c and inclined at 60 ° are formed as shown in FIG. Opposite to this, a space portion 14c having a regular triangular cross-sectional shape with a vertex angle of 60 °, an upper end opening, and expanding upward at an angle of 60 ° is formed.
In this case, the space part 14c is formed so as to straddle between the cement boards 10b and 10c, and is closed at the lower end side by the vertical parts 19b and 19c contacting each other. When such a space 14c is formed, the space 14c is filled with the adhesive 12 mixed with an inorganic particulate material such as silica sand.
[0044]
In this case, the filling amount of the adhesive 12 is an amount that can prevent the outflow of the concrete C and the outflow of the water to be poured later, and an amount corresponding to a part thereof, for example, approximately half the height of the space 14c. Or about half of the total filling amount.
[0045]
Next, as shown in FIG. 7, concrete C is cast on the back side of the cement boards 10b and 10c. When the placement of the concrete C is completed, as shown in FIG. 8, when the remaining adhesive 12 is filled in the space 14c and the adhesive 12 is hardened, the adhesive between the cement boards 10b and 10c is fixed. And the joining is completed.
[0046]
According to the joining method configured as described above, a part of the adhesive 12 is filled before the concrete C is poured, and the remaining is filled after the concrete C is poured. It can be finished neatly while preventing outflow.
[0047]
The present inventors prepared three types of specimens A, B, and C corresponding to the first to third examples (see FIG. 9), and performed tensile and bending tests. Was. A 8 mm-thick Powerlon board (trade name, manufactured by Kuraray Co., Ltd.) was used as the cement board.
The adhesive was obtained by adding No. 7 silica sand to a commercial adhesive Seakadur W (trade name, manufactured by Nippon Sika Co., Ltd.) in which an epoxy resin base material and a curing agent were mixed so as to be 50% by weight. Was used.
[0048]
The adhesive was filled in the space using a filling gun used for applying the sealing agent. Table 1 below shows the properties of the materials used.
[Table 1]

[0049]
For the tensile test, a test piece similar to the test piece shown in FIG. 9 was prepared, and cut out therefrom to obtain a test piece. In the pulling method, a test specimen having a width of 40 mm and a total length of 300 mm was directly sandwiched between chucks of an autograph with the bonding surface as a center, and a test was performed at a test speed of 0.3 mm / min and a distance between chucks of 200 mm. The test results are shown in Table 2 below.
[Table 2]

[0050]
In this tensile test, all fractures resulted in interfacial peeling at the bonding surface. As is clear from the test results, the test piece A having the spread angle of 45 ° and the test piece B having the spread angle of 30 ° show a large variation due to the effect of the unfilled portion and a considerably low tensile strength. Value. On the other hand, in the specimen C having the spread angle of 60 °, the unfilled portion was not observed by visual observation, and the tensile strength was 7.15 N / mm 2, which is about half of the base metal tensile strength. Was.
The bending test was performed by the method shown in FIG. In this test, the distance between supports was 800 mm with a two-point load having an equal bending section. The test results are shown in Table 3 below.
[Table 3]

[0051]
In this bending test, all failures were interfacial delaminations at the bonding surface. In particular, in this test result, the specimen A having an expansion angle of 45 ° and the specimen B having an expansion angle of 30 ° have no expansion angle, that is, at the interface on the 90 ° side, Destruction occurred in such a way as to take in the base material (cement board).
[0052]
In the specimen C having the spread angle of 60 °, in the destruction of the bonding surface, the specimen was broken by taking in more base material than the other specimens, and the shape was close to the fracture of the base material.
In addition, in the specimen C, only 60-3 has the adhesive disturbed on the surface on the side opposite to the expanded portion, and as a result, the maximum strength is higher than that of the other specimens 60-1 and 60-2. It is presumed to have grown.
In addition, when the situation of the fractured surface was photographed and observed, a part of the specimen was found to be filled with the adhesive, and the unfilled part tended to be less filled as the spread angle was smaller. was there.
[0053]
In addition, in the embodiment shown in FIGS. 6 to 8, the case in which the adhesive 12 to be filled in the space 14 c is performed twice is illustrated, but before the concrete C is cast, the space 12 c May be filled with the entire amount.
[0054]
【The invention's effect】
As described in detail above, according to the joining structure and the joining method of the cement board for permanent form according to the present invention, a constant joining strength is relatively easily secured without taking much time and effort, It is also possible to prevent contamination of the joint.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a principal part showing a first embodiment of a joining structure of a cement board for a permanent form according to the present invention.
FIG. 2 is a plan view of a cement board used in the joining structure shown in FIG.
FIG. 3 is an explanatory view of an end of a cement board used in the joining method according to the present invention.
FIG. 4 is a cross-sectional view of a principal part showing a second embodiment of the joining structure of the cement board for a permanent form according to the present invention.
FIG. 5 is a sectional view of a principal part showing a third embodiment of the joining structure of a cement board for a permanent form according to the present invention.
FIG. 6 is an explanatory sectional view of an initial step showing another embodiment of the joining method according to the present invention.
FIG. 7 is an explanatory cross-sectional view of a step performed subsequent to FIG. 6;
FIG. 8 is an explanatory cross-sectional view of a step performed subsequent to FIG. 7;
FIG. 9 is an explanatory view of a test piece used in a test performed to confirm the operation and effect of the present invention.
FIG. 10 is an explanatory diagram of a test method of a bending test performed to confirm the operation and effect of the present invention.
[Explanation of symbols]
10, 10a, 10b, 10c Cement board 12 Adhesive 14 Space 16 Adhesive sheet 18 Cut surface 20 Vertical surface

Claims (9)

In a joining structure of a cement board for permanent form, a flat cement board is arranged vertically and horizontally adjacent to each other, and a joint between a pair of adjacent cement boats is fixed via an adhesive.
The adhesive is composed of a mixture of an epoxy resin main agent, a curing agent, and inorganic particles such as silica sand,
Forming a space part that expands outward at the joint part, filling the space part with the mixture, and curing the same, thereby adhering and fixing between adjacent cement boards. Joint structure of cement board for frame. The cement board for a permanent form according to claim 1, wherein the inorganic particulate material such as silica sand is mixed in the mixture in an amount of 30 to 50% by weight. The space portion is formed by forming a cut surface having an inclination angle of 30 to 45 ° on one contact end surface of the cement board to be installed adjacently and abutting the cut surface on the end surface of the other cement board. The joint structure of a cement board for a permanent form according to claim 1 or 2, wherein The cement board for a permanent form according to claim 3, wherein the cut surface is formed on both of the cement boards that are installed adjacent to each other, and the space is formed so as to straddle between the cement boards. Joint structure. The joint structure of a cement board for a permanent form according to claim 4, wherein the expansion angle of the space is 60 °. In a method for joining a cement board when the cement board is used as a permanent form by placing a flat cement board adjacently in the vertical and horizontal directions and pouring concrete behind the rear thereof, By forming a space portion that expands toward the space portion, and filling the space portion with a mixture of an epoxy resin main agent, a curing agent, and inorganic particulate matter such as silica sand, and curing the space portion, the space between adjacent cement boards is filled. Bonding a cement board for permanent formwork, wherein the cement board is bonded and fixed. Before pouring the concrete, the concrete is filled partly into the space to ensure water-stop, and after the concrete is poured, the remaining part is filled into the space. The method for bonding a cement board for a permanent form according to claim 6. The cement board for a permanent form according to claim 7, wherein the partial filling amount is an amount corresponding to approximately half the height of the space portion, or approximately half the total filling amount. Joining method. The cement board for permanent formwork according to claim 6, wherein the mixture adheres an adhesive sheet to the back side of the space, and after the concrete is poured, the space is filled. Joining method.

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