JP2017203252A - Repair method and installation method of box culvert - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a repair method of a box culvert that enables the box culvert to be repaired readily at a site.SOLUTION: A repair method is for a connection joint part 10a as a joint material 2 ages, the joint material being of a box culvert formed by a continuously installed concrete box body 10 made of a concrete box body 1 and the joint material 2 filled in the connection joint part 10a between the concrete box bodies, the concrete box body 1 having a penetrating hollow part 1a and being connected to each other such that the hollow parts 1a communicate with each other. At least a ceiling part of the connection joint part 10a is covered by a protective sheet 3 having a cohesive layer laminated on a base material layer and the cohesive layer is adhered on a concrete wall of the concrete box body 1, thereby preventing falling and outflow of the aged joint material, sediment, and moisture contained in the sediment from the ceiling part of the connection joint part 10a.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a repair method and a construction method for a box culvert composed of a concrete box continuous structure.

  A box culvert is a concrete box having a hollow portion that penetrates, and is a concrete box continuous structure in which the concrete boxes are connected in series so that the hollow portions communicate with each other. It is used under the road, and the hollow part is used as a waterway, a sidewalk, an underpass of a roadway, and a communication line accommodating part.

  In this construction, bituminous joint plates made mainly of asphalt (asphalt mixture, trade name: elastite, etc.) for the purpose of preventing water from flowing into the hollow parts and inflow of earth and sand at the joints between the concrete boxes. As a joint material, etc., the joint material 2 changes over time as shown in FIG. 7 (a) due to long-term use for over 10 years after construction, and the joint material jumps out or peels off. Problems such as cracks in the joint material filling portion, and earth and sand and moisture contained in the earth and sand from the joint joint (for example, groundwater, rainwater, etc.) are liquid and / or solid (icicles, etc.) The problem of spilling out has occurred.

  At present, as a countermeasure, as shown in FIG. 7 (b), the joint material 2 is removed from the concrete surface due to secular change in the joint portion 10a of the ceiling portion on the hollow portion side of the concrete box continuous body. In addition, a cover member 90 having a cross-sectional shape made of a metal plate such as a tin plate or a plastic molded product and having an upward opening is prepared, and a hole is made in the concrete wall surface of the concrete box 1 to connect the ceiling portion. A method is employed in which the cover member 90 is hit by an anchor bolt 91 and stopped so as to cover the portion. According to the cover member 90, it is possible to prevent the joint material 2 from the connection joint portion 10a from being received and peeled down, and to prevent the earth and sand from flowing out from the connection joint portion 10a and water leakage.

However, this method has the following problems.
i Since the dimensions and shape of the connection joint are different for each constructed concrete box continuous body, it is necessary to make a custom-made cover member, and it takes time to install the cover member.
ii Since the anchor bolt is used for fixing the cover member, the concrete box is damaged.
iii It is difficult for the cover member to follow the movement of the concrete box such as vibration in the concrete box continuous body by fixing with the anchor bolt.
Since the protrusion of the cover member from the ceiling on the hollow portion side of the iv concrete box continuous body is about 40 mm, there is a case where a damage accident occurs in which the cover member is damaged due to contact with a passing vehicle. When the cover member is damaged, it is necessary to pay attention to a secondary disaster caused by the broken pieces. Therefore, after the accident, it is necessary to remove the broken pieces and the damaged cover member.
v With the metal cover member, the state of the connection joint portion of the covered portion cannot be seen. Moreover, when a metal cover member is damaged, there is a risk of injury at the corner of the damaged portion.
vi Plastic cover members may generate toxic gases in the event of a fire.
In addition, as a prior art relevant to this invention, the following are mentioned, for example.

Japanese Patent Laid-Open No. 9-32090 Japanese Patent Laid-Open No. 10-184921 JP 2001-25300 A

  The present invention has been made in view of the above circumstances, and it is possible to easily repair and construct the connection joint portion of the continuous connecting body of the concrete box on the site without damaging the concrete box. It aims at providing the repair method and construction method of a box culvert which can suppress the damage by the contact of the passing vehicle of a construction location.

In order to achieve the above object, the present invention provides the following box culvert repair method and construction method.
[1] From a concrete box continuous structure which is constructed by connecting concrete boxes with hollow parts penetrating so that the hollow parts communicate with each other, and filling joint material between the joints of the concrete boxes. In the box culvert, a method of repairing a joint joint part accompanying aging of the joint material, which covers a protective sheet in which an adhesive layer is laminated on a base material layer at least on the ceiling part of the joint joint part, The box culvert is characterized in that it adheres or adheres to a concrete wall of a concrete box to prevent aged joint material, earth and sand, and moisture contained in the earth and sand from falling and flowing out from the ceiling portion of the joint joint. Repair method.
[2] The protective sheet is a base material layer made of ethylene propylene diene rubber, chloroprene rubber, styrene butadiene rubber, acrylic rubber, urethane rubber, acrylic silicone rubber or silicone rubber, or a base material layer made of epoxy fiber reinforced plastic. And a method for repairing a box culvert according to [1], including a silicone-based adhesive layer, an acrylic adhesive layer, an acrylic silicone-based adhesive layer, or a urethane-based adhesive layer.
[3] The protective sheet is a base material layer made of silicone rubber having a hardness of 10 to 90 according to a durometer A hardness meter defined in JIS K 6249;
(A) an organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule;
(B) R ₃ SiO _1/2 unit (wherein R is an unsubstituted or substituted monovalent hydrocarbon group, but R contains an alkenyl group) and a resinous material mainly composed of SiO ₂ unit Polymer,
(D) an organohydrogenpolysiloxane containing at least two hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule;
(E) A cured product of an addition-curable silicone rubber composition or a silicone gel composition, wherein the cured product contains an addition reaction catalyst and has surface tackiness, and a silicone-based adhesive having an Asker C hardness of 1 to 60 The box culvert repair method according to [2], including a layer.
[4] The box culvert repair method according to any one of [1] to [3], wherein the protective sheet is transparent or translucent.
[5] The box culvert repair method according to any one of [1] to [4], wherein the protective sheet has a thickness of 0.5 to 8 mm.
[6] The box culvert repair method according to any one of [1] to [5], wherein the joint material includes asphalt as a main material.
[7] A box made of a concrete box continuous structure in which concrete boxes having hollow parts that pass through are connected to each other so that the hollow parts communicate with each other, and the joint material between the concrete boxes is filled with joint material. When installing a culvert, cover a protective sheet in which an adhesive layer is laminated on a base material layer on at least the ceiling portion of the connection joint, and adhere or adhere the adhesive layer to a concrete wall of a concrete box, A box culvert construction method characterized by preventing joint material, earth and sand, and moisture contained in the earth and sand from falling from the ceiling portion of the joint joint.
[8] The protective sheet is made of ethylene propylene diene rubber, chloroprene rubber, styrene butadiene rubber, acrylic rubber, urethane rubber, acrylic silicone rubber or silicone rubber, or a base material layer made of epoxy fiber reinforced plastic. And a box culvert construction method according to [7], including a silicone-based adhesive layer, an acrylic adhesive layer, an acrylic silicone-based adhesive layer, or a urethane-based adhesive layer.
[9] The protective sheet is a base material layer made of silicone rubber having a hardness of 10 to 90 according to a durometer A hardness meter defined in JIS K 6249;
(A) an organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule;
(B) R ₃ SiO _1/2 unit (wherein R is an unsubstituted or substituted monovalent hydrocarbon group, but R contains an alkenyl group) and a resinous material mainly composed of SiO ₂ unit Polymer,
(D) an organohydrogenpolysiloxane containing at least two hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule;
(E) A cured product of an addition-curable silicone rubber composition or a silicone gel composition, wherein the cured product contains an addition reaction catalyst and has surface tackiness, and a silicone-based adhesive having an Asker C hardness of 1 to 60 The box culvert construction method according to [8], including a layer.

  According to the present invention, since a thin protective sheet can be repaired or constructed simply by adhering to a concrete wall of a concrete box, there is no need to make a custom order like a cover member, and on-site repair or construction can be easily performed. This can be done without damaging the box. In addition, if the protective sheet is attached with adhesive, the protective sheet can flexibly follow the movement of the concrete box due to the difference in temperature and vibration of the concrete box continuous body. Moreover, since it is a thin protective sheet, the protrusion from the hollow part side ceiling of a concrete box continuous body is slight, and the damage by the contact of a passing vehicle can be suppressed as much as possible. Further, if the base material layer of the protective sheet is a rubber elastic body, even if a damage accident occurs, the influence of the secondary disaster is slight and the repair is easy.

It is a side schematic diagram showing an example of composition of a concrete box connection object. It is AA sectional drawing of the connection joint part at the time of the facility of the concrete box continuous connection body shown in FIG. It is a ceiling fragmentary sectional view after the secular change of the connection joint part of a concrete box continuous connection body. It is sectional drawing of the connection joint part of the ceiling part which applied this invention to the concrete box continuous structure shown in FIG. 1, (a) is sectional drawing of the length direction of a concrete box continuous body, (b ) Is an AA cross-sectional view. It is sectional drawing which shows the structural example of the protection sheet used by this invention. It is sectional drawing which shows the other structural example of the connection joint part of the ceiling part after applying the repair method of the box culvert which concerns on this invention. It is sectional drawing of the connection joint part which shows the repair state of the ceiling part in the repair method of the conventional box culvert, (a) is the state before repair, (b) shows the state which attached the protective cover.

The box culvert repair method according to the present invention will be described below.
The repair method of the box culvert according to the present invention is a facility in which concrete boxes having a hollow portion that penetrates are connected to each other so that the hollow portions communicate with each other, and the joint material between the concrete boxes is filled with a joint material. A method for repairing a box culvert composed of a continuous box of concrete boxes, covering at least the connecting joints of the concrete boxes across the connecting joints of the ceiling and covering the connecting joints. The protective sheet is affixed to the concrete wall surface of the concrete box near the connection joint portion by adhesion or adhesion.

  Here, as shown in FIG. 1, the provided concrete box continuous body 10 is formed by connecting the concrete boxes 1 having the hollow portions 1 a so that the hollow portions 1 a communicate with each other. The joint material 2 is filled in the joint portion 10 a between the boxes 1. Such a concrete box continuous structure 10 is installed in the ground or under the road, and the hollow portion 1a is used for a waterway, a sidewalk, an underpass of a roadway, a three-dimensional intersection road, a communication line accommodating part, or the like.

  The concrete box 1 is called a box culvert and is often a precast concrete product. Moreover, the dimensions of the concrete box 1 are, for example, about 1 m × 1 m to 5 m × 30 m in length and width and about 5 to 50 m in length.

  The joint material 2 is filled in the joint portion 10a of the concrete box 1 to prevent water stoppage and inflow of earth and sand into the hollow portion 1a, and a joint material mainly composed of asphalt is preferable. It consists of a textured board (asphalt mixture, trade name: elastite, etc.).

  The connection joint portion 10a is a joint portion formed by the end faces (connection surfaces) of the concrete box 1 when the concrete boxes 1 are arranged so as to be close to each other. The width of the connection joint portion 10a (the interval between the end surfaces (connection surfaces) of the concrete box 1) is about 30 to 150 mm.

Here, at the time of installation of the concrete box continuous structure 10, as shown in FIG. 2, the joint material 2 is densely filled into the connection joint part 10a without protruding into the hollow part 1a.
When more than 10 years have passed since the facility, the joint material 2 changes over time as shown in FIG. 3 and protrudes from the connection joint portion 10a toward the hollow portion 1a or peels off. At the same time, the joint material 2 is not sufficiently filled in the joint portion 10a, and there is a possibility that earth and sand or rainwater from the outside flows out from the joint portion 10a. This phenomenon is remarkable at the ceiling portion of the concrete box continuous structure 10. FIG. 3 is a cross-sectional view of the ceiling portion including the connection joint portion 10a of the concrete box continuous body 10. The upper side of the figure is the outside of the concrete box continuous body 10, and the lower side of the figure is the hollow portion 1a. On the side. 3 is the direction in which the hollow portion 1a communicates (the length direction of the concrete box connecting body 10 and the width direction of the connection joint 10a), and the direction perpendicular to the paper surface is the concrete box connecting body 10. It is a width direction (length direction of the connection joint part 10a).
The repair method of the present invention is performed in order to prevent or prevent such problems, and is performed according to the following procedure.

  In this case, a protective sheet having a base material layer and an adhesive layer on one side is used as a protective sheet for repair. First, as shown in FIG. 3, the joint material 2 may be in a protruding state. For example, the protruding portion is removed. In this case, when there is a gap in the connection joint 10a, the gap can be filled with a sealing material, for example, a silicone sealing material, if necessary. A commercially available sealing material can be used.

  Then, if necessary, after surface adjustment such as removing dirt on the concrete wall of the concrete box 1 to which the adhesive layer is applied, the connection to repair the protective sheet 3 as shown in FIG. The adhesive layer is bonded to the concrete wall surface of the concrete box 1 so as to cover the joint portion 10a.

  As shown in FIG.4 (b), the partial removal of the joint material 2 in the hollow part 1a side of the connection joint part 10a is given over the full length of the ceiling part and side wall part of the concrete box continuous body 10 Yes. Further, the protective sheet 3 is attached to the entire length of the ceiling portion of the concrete box continuous body 10 and the upper portions of both side walls. The protective sheet 3 may be applied to the entire length of each side wall of the concrete box connecting body 10 (that is, up to the bottom), or up to about 10 cm above the bottom, but at least the ceiling portion is protected. A sheet is pasted.

  As the protective sheet 3 is attached, one sheet may cover at least the entire connection joint portion 10a of the ceiling portion, or at least the entire connection joint portion 10a of the ceiling portion while overlapping a plurality of sheets with a predetermined width. May be covered.

  Here, as a base material layer of the protective sheet 3, a base material layer made of ethylene propylene diene rubber, chloroprene rubber, styrene butadiene rubber, acrylic rubber, urethane rubber, acrylic silicone rubber or silicone rubber, or epoxy fiber reinforced plastic A base material layer made of is preferable. In consideration of using the protective sheet 3 outdoors, a material having long-term heat resistance, cold resistance, and weather resistance, and having as little temperature dependence as possible is preferable, and a material that has good compatibility with the adhesive layer. There is also a need to consider. From these points, a base material layer made of silicone rubber is more preferable.

  The protective sheet 3 made of the base material layer may be adhered and adhered to a predetermined concrete surface using an adhesive, but in consideration of the construction, the protective sheet 3 may be re-applied. It is preferable that the adhesive layer is pasted using an adhesive layer provided on the base material layer.

  The adhesive layer is preferably a silicone adhesive layer, an acrylic adhesive layer, an acrylic silicone adhesive layer, or a urethane adhesive layer. Among these, in the case of an acrylic pressure-sensitive adhesive layer, it is preferable to form a base treatment film with a primer in order to allow the protective sheet 3 to be attached again. In the case of a urethane-based adhesive layer, it is preferable to form a primer treatment film with a primer in order to ensure sufficient adhesion. Considering the use of the protective sheet 3 outdoors, the adhesive layer is preferably made of a material that can withstand various environments such as a cold region and a hot and humid region, and therefore, a silicone-based adhesive layer is more preferable.

In FIG. 5, the structural example of the protection sheet 3 used by this invention is shown.
As shown in FIG. 5, the protective sheet 3 is formed by laminating an adhesive layer 3b on one side of a base rubber (base material layer) 3a, and is usually laminated on the adhesive layer 3b so that the cover film 3c can be peeled off. In use, the cover film 3c is peeled off, and the adhesive layer 3b is adhered to the concrete surface at the required place.

Here, as a rubber base | substrate which comprises the said base rubber, a silicone rubber is preferable from the point which has heat resistance, a weather resistance, and cold resistance. Silicone rubber having a hardness of 10 to 90, more preferably 20 to 80, still more preferably 25 or more, especially 40 or more and 80 or less, particularly 75 or less as measured by durometer A hardness tester specified in JIS K 6249. It is preferable to use rubber in terms of elasticity and rubber strength. When the hardness is less than 10, the strength as rubber may be inferior, and when it exceeds 90, the elasticity may be inferior.
In the present invention, a rubber having a rubber hardness (that is, a hardness by a durometer A hardness meter specified in JIS K 6249) of 1 or more and showing an effective rubber hardness value is a silicone rubber (composition that gives the cured product). Is a silicone gel (the composition that gives the cured product is a silicone gel composition) that is so hard that the rubber hardness is less than 1 and does not exhibit an effective rubber hardness value.

  The silicone rubber composition for obtaining the silicone rubber is an addition (hydrosilylation) reaction-curing type silicone rubber composition or an organic peroxide-curing type silicone rubber composition because molding can be performed in a short time by heating. What is obtained is preferred. This addition reaction curable silicone rubber composition has an alkenyl group-containing organopolysiloxane having two or more alkenyl groups typified by vinyl groups in one molecule, and two or more, preferably 3 SiH groups in one molecule. One or more organohydrogenpolysiloxanes (usually in an amount such that the molar ratio of SiH groups to alkenyl groups is 0.5 to 4) and platinum group metal-based addition reaction catalysts represented by platinum or platinum compounds (usually alkenyls) What contains 1-1,000 ppm) with respect to group containing organopolysiloxane is used. Further, the organic peroxide curable silicone rubber composition may be of a known composition, preferably an effective amount of organic peroxide as a curing agent in organopolysiloxane having two or more alkenyl groups in one molecule. What is blended (usually 1 to 10 parts by mass with respect to 100 parts by mass of the organopolysiloxane) is used.

  A commercially available product can be used as the silicone rubber composition that gives the cured silicone rubber having a hardness of 10 to 90 according to JIS K 6249 as measured by a durometer A hardness meter. For example, as an addition reaction curable silicone rubber composition KE-1935A / B, KE-1950-60A / B, KEG-2000-40A / B, etc. manufactured by Shin-Etsu Chemical Co., Ltd. are used as organic peroxide-curing silicone rubber compositions as Shin-Etsu Chemical Co., Ltd. KE-551-U, KE-571-U, KE-1571-U, KE-951-U, etc. are used. In addition, a glass cloth may be put into the base rubber to improve the strength.

  The adhesive layer is composed of an adhesive silicone rubber or gel. In particular, by using an addition-curable silicone rubber composition or a cured product of the silicone gel composition, a certain rubber hardness and rubber strength can be obtained. While having it, it can also have the adhesiveness which adheres and can fix to base rubber and a concrete surface.

Here, as the adhesive layer,
(A) an organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule;
(B) R ₃ SiO _1/2 unit (wherein R is an unsubstituted or substituted monovalent hydrocarbon group, but R contains an alkenyl group) and a resinous material mainly composed of SiO ₂ unit Polymer,
(D) an organohydrogenpolysiloxane containing at least two hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule;
(E) It is preferable that the cured product containing an addition reaction catalyst is formed from a cured product of an addition-curable silicone rubber composition or a silicone gel composition having surface tackiness.
In this case, the addition-curable silicone rubber composition or the silicone gel composition may further comprise (C) R ′ ₃ SiO _1/2 unit (wherein R ′ is an unsubstituted or substituted monovalent hydrocarbon group, if necessary). However, R ′ does not contain an alkenyl group, or it contains a resinous copolymer containing SiO ₂ units as a main component, even if it contains an alkenyl group (or an amount less than the alkenyl group content of component (B)). Also good.

The component (A) of the addition-curable silicone rubber composition or the silicone gel composition is an organopolysiloxane having at least two alkenyl groups on average in one molecule. As the organopolysiloxane of the component (A), The following average composition formula (1)
R ¹ _a SiO _{(4-a) / 2} (1)
What is shown by is used.

In the formula, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having the same or different carbon number of 1 to 10, preferably 1 to 8, and a is 1.5 to 2.8, preferably 1.8. It is a positive number in the range of ˜2.5, more preferably 1.95 to 2.05. Here, as the unsubstituted or substituted monovalent hydrocarbon group bonded to the silicon atom represented by R ¹ , a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, Pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, alkyl group such as decyl group, aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group, benzyl group, phenylethyl group, phenylpropyl Aralkyl groups such as groups, vinyl groups, allyl groups, propenyl groups, isopropenyl groups, butenyl groups, hexenyl groups, cyclohexenyl groups, octenyl groups and other alkenyl groups, and some or all of the hydrogen atoms of these groups are fluorine. Substituted with halogen atoms such as bromine, chlorine, cyano groups, etc., such as chloromethyl group, chloropro Group, bromoethyl group, trifluoropropyl group, but cyanoethyl group and the like, Preferably, at least 90 mol% of all R ¹ is a methyl group.

In this case, at least two of R ¹ must be alkenyl groups (preferably having 2 to 8 carbon atoms, more preferably 2 to 6). The content of the alkenyl group is 0.0001 to 20 mol%, preferably 0.001 to 10 mol%, particularly in the total organic group (that is, the above-mentioned unsubstituted or substituted monovalent hydrocarbon group) R ^1. It is preferable to set it as 0.01-5 mol%. This alkenyl group may be bonded to a silicon atom at the end of the molecular chain, or may be bonded to a silicon atom in the middle of the molecular chain, or may be bonded to both. Those containing bonded alkenyl groups are preferred.

The degree of polymerization is not particularly limited and can be from liquid to raw rubber at normal temperature. Usually, the average degree of polymerization in terms of polystyrene by gel permeation chromatography (GPC) is 50 to 20,000, preferably 100. Those having a molecular weight of about 10,000 to 10,000, more preferably about 100 to 2,000 are preferably used.
The structure of this organopolysiloxane is basically composed of a repeating main chain consisting of diorganosiloxane units (R ¹ ₂ SiO _2/2 ), and both ends of the molecular chain are triorganosiloxy groups (R ¹ ₃ SiO _{1 / 2} ) or a linear structure blocked with a hydroxydiorganosiloxy group ((HO) R ¹ ₂ SiO _1/2 ), but may be partially a branched structure, a cyclic structure, or the like.

The component (B) resinous copolymer (that is, a copolymer having a three-dimensional network structure) is an alkenyl group-containing resinous copolymer mainly composed of R ₃ SiO _1/2 units and SiO ₂ units. is there. Here, R is an unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms. Examples of the monovalent hydrocarbon group represented by R include a methyl group and an ethyl group. Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, alkyl group such as nonyl group, decyl group, phenyl group, tolyl group, xylyl Group, aryl group such as naphthyl group, aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group, vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group, etc. Or some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine, bromine and chlorine, cyano groups, etc. Those conversion, such as chloromethyl group, chloropropyl group, bromoethyl group, trifluoropropyl group, cyanoethyl group and the like.

The (B) component alkenyl group-containing resinous copolymer may be composed of only the above R ₃ SiO _1/2 unit and SiO ₂ unit, and if necessary, R ₂ SiO unit or RSiO _{3 / 2} units (R is as defined above) as the total amount thereof, with respect to the total copolymer mass, 50% or less, preferably comprise from 40% or less but, R ₃ SiO _1/2 units and SiO The molar ratio [R ₃ SiO _1/2 / SiO ₂ ] to ₂ units is preferably 0.5 to 1.5, particularly preferably 0.5 to 1.3. Even if this molar ratio is smaller than 0.5 or larger than 1.5, sufficient hardness and strength as an adhesive layer cannot be obtained. Furthermore, the resinous copolymer of component (B) has at least two alkenyl groups in one molecule. In this case, the content of the alkenyl group is usually 0.00005 mol / g or more, preferably 0.0001 mol / g or more, more preferably 0.0001 to 0.003 mol / g, still more preferably 0.00. It is the range of 0002-0.002 mol / g. If the alkenyl group content is less than 0.00005 mol / g, sufficient rubber or gel properties as the adhesive layer cannot be obtained. If it exceeds 0.003 mol / g, the hardness becomes too high and the adhesive strength is too high. May decrease.
The resinous copolymer may be a liquid (for example, 10 mPa · s or more, preferably 50 mPa · s or more) having fluidity at room temperature (25 ° C.) or a solid having no fluidity. . This resinous copolymer can be usually produced by hydrolyzing an appropriate chlorosilane or alkoxysilane by a method well known in the art.

  The blending amounts of the above components (A) and (B) are 20 to 100 parts by weight, particularly 30 to 90 parts by weight, when the total of components (A) and (B) is 100 parts by weight. Yes, component (B) is 0 to 80 parts by mass, particularly 10 to 70 parts by mass. When the amount of the component (A) is too small, the elasticity as the adhesive layer is lost and brittle, and when it is too large, the adhesiveness and strength are insufficient. When there are too many (B) components, adhesiveness will also fall and the rubber | gum or gel physical property as an adhesion layer will fall remarkably.

In the present invention, in addition to the alkenyl group-containing resinous copolymer of component (B), optionally, as a component (C), the functionality involved in the hydrosilylation addition reaction of alkenyl groups in the molecule. A (nonfunctional) resinous copolymer containing no group can be blended. The resinous copolymer of component (C) (that is, a copolymer having an alkenyl group-free three-dimensional network structure) contains R ′ ₃ SiO _1/2 units and SiO ₂ units as main components. Here, R ′ is an unsubstituted or substituted monovalent hydrocarbon group excluding an alkenyl group, preferably having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, and the monovalent hydrocarbon group represented by R ′ is Alkyl group such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, phenyl Group, aryl group such as tolyl group, xylyl group, naphthyl group, aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group, vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexane Alkenyl groups such as hexenyl and octenyl groups, and some or all of the hydrogen atoms in these groups are halogenated such as fluorine, bromine and chlorine. Atom and substituted with a cyano group or the like, such as chloromethyl group, chloropropyl group, bromoethyl group, trifluoropropyl group, cyanoethyl group and the like.

The resinous copolymer of component (C) may be composed only of the above R ′ ₃ SiO _1/2 units and SiO ₂ units, and if necessary, R ′ ₂ SiO units and R′SiO _{3 / 2} units (R 'above street of) the total amount of these with respect to the total copolymer mass, 50% or less, and preferably may comprise from 40% or less, R' ₃ SiO _1/2 The molar ratio [R ′ ₃ SiO _1/2 / SiO ₂ ] between the unit and the SiO ₂ unit is preferably 0.5 to 1.5, particularly preferably 0.5 to 1.3. Even if this molar ratio is smaller than 0.5 or larger than 1.5, the tackiness is lowered.
The resinous copolymer may be a liquid that is fluid at room temperature (for example, 25 ° C.) or a solid that is not fluid. However, the resinous copolymer may be solid at room temperature in terms of stickiness of the cured product. preferable. This resinous copolymer can be usually produced by hydrolyzing an appropriate chlorosilane or alkoxysilane by a method well known in the art.

  The blending amount of the component (C) is preferably 0 to 400 parts by weight, particularly preferably 0 to 300 parts by weight with respect to 100 parts by weight of the total amount of the components (A) and (B). When there are too many (C) components, adhesiveness falls and there exists a possibility that the rubber | gum or gel physical property as an adhesion layer may also fall.

The component (D) is an organohydrogenpolysiloxane having at least 2, preferably 3 or more hydrogen atoms (SiH groups) bonded to silicon atoms, and the SiH group in the molecule is the above (A). The alkenyl group bonded to the silicon atom in the component, the component (B) and the component (C) is cross-linked by a hydrosilylation addition reaction, and acts as a curing agent for curing the composition. The organohydrogenpolysiloxane of component (D) has the following average composition formula (2)
R ² _b H _c SiO _{(4-bc) / 2} (2)
(Wherein R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, b is 0.7 to 2.1, c is 0.001 to 1.0, and b + c is a positive number satisfying 0.8 to 3.0.)
And those having at least 2 (usually 2 to 200), preferably 3 to 100, more preferably 3 to 50 silicon atom-bonded hydrogen atoms in one molecule are suitably used. Here, examples of the monovalent hydrocarbon group for R ² include the same groups as those exemplified for R ¹ , but those having no aliphatic unsaturated group are preferred. Further, b is preferably 0.8 to 2.0, c is preferably 0.01 to 1.0, b + c is preferably 1.0 to 2.5, and the molecular structure of the organohydrogenpolysiloxane is: The structure may be any of linear, cyclic, branched, and three-dimensional network. In this case, the number of silicon atoms in one molecule (or the degree of polymerization) is preferably 2 to 300, particularly about 4 to 150 at room temperature (25 ° C.). In addition, the hydrogen atom couple | bonded with a silicon atom may be located in any of the molecular chain terminal and the middle of a molecular chain, and may be located in both.

Further, instead of or in addition to the organohydrogenpolysiloxane of the above formula (2), a resinous copolymer having R ″ ₂ HSiO _1/2 units and SiO ₂ units as main components, or R ′ A resinous copolymer mainly composed of ' ₂ HSiO _1/2 units, R ″ ₃ SiO _1/2 units and SiO ₂ units can be used. Here, R ″ is an unsubstituted or substituted monovalent hydrocarbon group, and examples thereof are the same as those of R ′, and those not containing an alkenyl group are preferable. The resinous copolymer may consist of only R ″ ₂ HSiO _1/2 units or R ″ ₂ HSiO _1/2 units, R ″ ₃ SiO _1/2 units and SiO ₂ units, If necessary, R ″ HSiO _2/2 units, R ″ ₂ SiO _2/2 units, HSiO _3/2 units, and R ″ SiO _3/2 units may be added to the total copolymer mass by 50. %, Preferably 40% or less, but the molar ratio of R ″ ₂ HSiO _1/2 unit, R ″ ₃ SiO _1/2 unit and SiO ₂ unit [(R ″ ₂ HSiO _1/2 + R ″ ₃ SiO _1/2 ) / SiO ₂ ] is preferably 0.5 to 1.5, particularly preferably 0.5 to 1.3.

Examples of the organohydrogenpolysiloxane of component (D) include trimethylsiloxy group-blocked methylhydrogenpolysiloxane at both ends, trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, and dimethylhydrogensiloxy groups at both ends. Blocked dimethylpolysiloxane, both ends dimethylhydrogensiloxy group blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group blocked methylhydrogensiloxane / diphenylsiloxane copolymer, both ends trimethylsiloxy group blocked methylhydrogen diphenylsiloxane-dimethylsiloxane copolymers, copolymers consisting of (CH _{3) 2} HSiO _1/2 units and SiO _4/2 units, (CH _{3) 2} H iO _1/2 unit and the SiO _4/2 units (C ₆ H _5), such as copolymers comprising SiO _3/2 units and the like.

  The compounding amount of the organohydrogenpolysiloxane of the component (D) is 0.5 to 30 parts by mass, particularly 0.6 to 20 parts by mass with respect to 100 parts by mass in total of the components (A) and (B). . If the blending amount is too small or too large, sufficient strength as an adhesive layer cannot be obtained. The organohydrogenpolysiloxane of component (D) is bonded to the silicon atom in component (D) relative to the alkenyl group bonded to the silicon atom included in components (A), (B), and (C). The amount of hydrogen atoms (SiH groups) is blended in such an amount that the molar ratio is 0.2 to 1.5, more preferably 0.25 to 1.2, and still more preferably 0.3 to 0.9.

  As an addition reaction catalyst for component (E), platinum black, platinum chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid and olefins, chloroplatinic acid and vinyl Examples include complexes with siloxanes, platinum-based catalysts such as platinum bisacetoacetate, palladium-based catalysts, and rhodium-based catalysts. In addition, the addition amount of this addition reaction catalyst can be made into a catalyst amount, and 0.5-1,000 ppm with respect to the total amount of (A), (B), (C) component as a platinum group metal normally, It is about 1 to 500 ppm.

Addition reaction curable silicone that contains the above components (A), (B), (D), and (E), and gives a silicone rubber or silicone gel having a surface tackiness of Asker C hardness of 1-60. Commercially available products can be used as the rubber composition or the silicone gel composition. For example, KE-1012A / B, KE-1056, KE-1151, FE-57, KE-1051JA / B manufactured by Shin-Etsu Chemical Co., Ltd. , Etc. are used.
In addition, about the hardened | cured material of the adhesion layer whose Asker C hardness is in the range of 1-60, the thing of Asker C hardness 14 or more and 60 or less is a silicone rubber, and the thing of Asker C hardness 1 or more and less than 14 is a silicone gel. is there.

  The addition-curable silicone rubber composition or silicone gel composition for forming the adhesive layer can be cured usually at 100 to 180 ° C., particularly at 110 to 140 ° C. for 5 to 20 minutes. Although a curing (post-cure) step is not necessary, it does not prevent post-curing in some cases.

The hardness of the adhesive layer is smaller than the hardness of the base rubber, and is preferably in the range of 1 to 60 in terms of Asker C hardness, more preferably in the range of 2 to 55, and still more preferably in the range of 2 to 40. is there. If it is less than 1, the strength as the adhesive layer may be inferior, and if it exceeds 60, the adhesiveness may decrease.
Moreover, based on JISZ0237, it adheres to glass (Nippon Sheet Glass Co., Ltd., FL2.0), and the adhesive force when performing a 180 ° peel test at a peeling speed of 300 mm / min is 0.5 to 10 N / 25 mm. In particular, 0.7 to 8 N / 25 mm is preferable. If it is less than 0.5 N / 25 mm, when sticking the adhesive layer to the desired part to be attached, the adhesive strength to the part to be attached is low, and there is a problem with sticking. Adhesion may be hindered.

  In addition to the above-described components, the composition for forming the base rubber layer and the adhesive layer includes, as necessary, other components such as fumed silica, precipitated silica, quartz powder, diatomaceous earth, and calcium carbonate. In addition, a filler such as carbon black, conductive zinc white, conductive powder such as metal powder, and heat-resistant agent such as iron oxide and cerium oxide may be blended. Furthermore, hydrosilylation reaction control agents such as nitrogen-containing compounds, acetylene compounds, phosphorus compounds, nitrile compounds, carboxylates, tin compounds, mercury compounds and sulfur compounds, internal mold release agents such as dimethyl silicone oil, adhesion promoters, thixotropes It is optional to add a property-imparting agent or the like.

  The thickness of the base rubber is preferably 0.2 to 5 mm, more preferably 0.5 to 5 mm, and particularly preferably 0.5 to 3 mm. If the thickness is less than 0.2 mm, it may be insufficient for taking advantage of the elasticity of the sheet. If the thickness exceeds 5 mm, the weight increases, affecting the attachment, and may be disadvantageous in terms of cost. Moreover, in order to ensure the adhesive force to a concrete surface, the thickness of the adhesion layer has the preferable range of 0.3-3 mm, More preferably, it is the range of 0.5-2 mm. Furthermore, it is preferable that the adhesive layer is as thick as possible within this range in order to absorb vibrations in the concrete box continuous structure. If it is less than 0.3 mm, it will not be possible to absorb the surface irregularities of the concrete surface, which is the part to be adhered, and if it exceeds 3 mm, the rubber strength of the affixed surface will depend on the adhesive layer and may cause rubber breakage. There is. That is, the thickness of the protective sheet 3 is preferably 0.5 to 8 mm.

  As shown in FIG. 5, when a protective sheet 3 made of a base rubber 3a made of silicone rubber and a silicone-based adhesive layer 3b is used, the protective sheet 3 is pasted with a non-primer unless the surface has large irregularities. Can do. In addition, as a width | variety stuck on the concrete wall surface of the concrete box 1 of the protective sheet 3, 100-400 mm, especially 150-250 mm are stuck to each concrete box 1 with respect to the both concrete boxes 1 which pinch | interconnect the joint joint part 10a, respectively. It is preferable to do so.

  The protective sheet 3 is preferably transparent or translucent. Thereby, the state of the connection joint part 10a and the surrounding concrete surface can be visually confirmed through the affixed protective sheet 3, and the deterioration of the adherend surface by visual inspection can be observed.

  When the protective sheet 3 is formed, an adhesive layer is laminated on the base rubber, and the adhesive layer is formed after the base rubber is formed by curing the composition forming the base rubber. Alternatively, the composition for forming the base rubber may be calendered on a film of polyethylene terephthalate (PET) or the like, and the composition for forming the adhesive layer in an unvulcanized state may be laminated. Good.

  The composition for forming the adhesive layer is preferably a method for obtaining a laminated sheet by dipping, coating, screen printing or the like on the base rubber layer or the composition for forming the same, and is preferable because coating molding can be suitably used. . In addition, as these hardening conditions, the range of 10 second-1 hour is preferable at 80-250 degreeC. Further, after-curing may be performed at 120 to 250 ° C. for about 1 to 100 hours for the purpose of removing low molecular siloxane.

  As described above, when the repair direction of the present invention is applied, as shown in FIG. 4, the protective sheet 3 is a joint material in at least the joint portion 10 a of the ceiling portion on the hollow portion 1 a side in the concrete box connecting body 10. 2 is prevented from popping out and peeling off (dropping off) and outflow of earth and sand. Further, there is no problem that icicles are formed in the connection joint portion 10a in a cold region.

Further, according to the present invention, since the thin protective sheet 3 is only attached to the concrete surface of the concrete box 1, there is no need to make a custom order like a cover member, and the field box can be easily repaired on site. This can be done without damaging 1. Moreover, since it is a thin protective sheet, the protrusion from the ceiling of the hollow part 1a of the concrete box continuous body 10 is slight, and damage due to contact with a passing vehicle can be suppressed as much as possible. Moreover, if the base material layer of the protective sheet 3 is a rubber elastic body, even if a damage accident occurs, the influence of the secondary disaster is slight and its repair is easy. Furthermore, even if a fire occurs in the hollow portion 1a, the protective sheet 3 made of the base rubber 3a made of silicone rubber and the silicone-based adhesive layer 3b does not generate harmful gas and has a self-extinguishing performance. It is safe.
In addition, if the protective sheet 3 is adhered with adhesive, the protective sheet 3 can flexibly follow the movement of the concrete box due to the difference in temperature and the vibration of the continuous box of the concrete box and vibrations such as vehicle traffic. Reliability is obtained.

  In addition, the water containing earth and sand may leak to the connection joint part 10a. In this case, as shown in FIG. 6, the drain pipe 6 is provided with a gap 4 for disposing the drain pipe 6 in the connection joint portion 10a, and the drain pipe 6 having a small hole through which only moisture is allowed to pass through the water containing soil and sand is formed in the gap 4. It can be provided and drained to the outside through this pipe.

  Further, a sealing material may be applied around the protective sheet 3. FIG. 6 shows a state in which the outer peripheral edge portion of the protective sheet 3 is bonded with the sealing material 5. When the protective sheet 3 is bonded with the sealing material 5 in this way, the outer peripheral edge side of the protective sheet 3 is sequentially turned up. Then, the outer peripheral edge side of the adhesive layer is peeled off slightly from the concrete surface, and the sealing material 5 may be supplied to the generated gap. As a result, the sealing layer 5 is formed on the outer peripheral edge of the adhesive layer.

  In addition, there is no restriction | limiting in particular as a sealing material, Any things, such as a well-known silicone type, a polysulfide type | system | group, a polyurethane type | system | group, can be used, However, A silicone sealing material is used suitably from the point of affinity with the material of the protection sheet 3. It is done. A commercially available product may be used as such a sealant. For example, as a silicone sealant, sealant master 300, sealant 70, sealant 701 and the like manufactured by Shin-Etsu Chemical Co., Ltd. can be used.

Next, a box culvert construction method according to the present invention will be described.
The construction method of the box culvert according to the present invention is a construction method that is performed on the connection joint portion when constructing the concrete box continuous body, and the content to be performed is basically the same as the above-described repair method of the box culvert of the present invention. Is the same. That is, the box culvert construction method of the present invention is such that the concrete boxes 1 having the hollow portions 1a that pass therethrough are connected so that the hollow portions 1a communicate with each other, and the connection joint portion 10a between the concrete boxes 1 is connected. A method for constructing a box culvert that fills the joint material 2, wherein the joint material 2 is filled in the joint joint portion 10 a, and then the adjacent joint material 10 a is sandwiched between the joint joint portions 10 a at least in the ceiling portion. The protective sheet 3 is bridged over the concrete wall surface of the box 1 to cover the connection joint 10a, and the protective sheet 3 is attached to the concrete wall of the concrete box 1 near the connection joint 10a by adhesion or adhesion.
Also by this construction method of the present invention, the same effect as the above-described repair method of the present invention can be obtained.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Example 1]
(Preparation of protective sheet)
A protective sheet was produced under the following conditions.
An addition reaction curable type of glass cloth having a thickness of 230 μm sized to a predetermined size (width: 600 mm, length: 400 mm) that gives a cured silicone rubber having a hardness of 57 by a durometer A hardness meter defined in JIS K 6249 Liquid silicone rubber composition; after being immersed in KE-1950-60A / B (manufactured by Shin-Etsu Chemical Co., Ltd.), the glass cloth after the immersion has a curing zone of 80 ° C. × 5 m + 100 ° C. × 5 m + 120 ° C. × 5 m The glass cloth was sealed by curing the impregnated liquid silicone rubber composition by passing it through a heating furnace at a speed of 1.5 m / min.
Next, after coating the above-mentioned liquid silicone rubber composition; KE-1950-60A / B with a thickness of 0.45 mm on the surface of one side of the sealed glass cloth, the curing zone is again 80 ° C. × 5 m + 100 ° C. × It passes through a heating furnace of 5 m + 120 ° C. × 5 m at a speed of 1.5 m / min, and has a cured silicone rubber layer having a JIS A hardness of 57 and a thickness of 0.45 mm on one surface and a thickness of about 0.7 mm. A glass cloth (base sheet) was produced.
Next, an addition reaction curable silicone gel composition that gives a cured silicone gel having Asker C hardness of 2 on the outer surface of the cured silicone rubber layer of the base sheet; KE-1012A / B (Shin-Etsu Chemical) Kogyo Co., Ltd.) was coated with a thickness of 1.0 mm, and then passed through a heating furnace having a cure zone of 110 to 150 ° C. × 3 m at a speed of 0.5 m / min. A laminated sheet (total thickness of about 1.7 mm) in which a silicone gel layer (adhesive layer) having a C hardness of 2 and a thickness of 1.0 mm is laminated is produced. Finally, an adhesive surface (silicone gel) of the laminated sheet is produced. A protective sheet to be subjected to a punching test was prepared by attaching a PET protective film to the layer surface).

(Punch test)
Using the obtained laminated sheet (protective sheet), a punching test was performed as follows.
The push-out test was conducted by “NEXCO Test Method Vol. 7 Tunnel Test Method (July 2013) by East Japan Expressway Co., Ltd., Central Japan Expressway Co., Ltd. and West Japan Expressway Co., Ltd. Test Method 734-2011 Prevention of tunnel flaking The test was carried out according to “Punching test method for fiber sheet adhesive for use”. That is, first, a hole for inserting a punching indenter was provided in the central part of a concrete flat plate (width 600 mm, length 400 mm, thickness 60 mm), and a separately prepared concrete indenter was placed in the hole. After fixing the indenter, the PET protective film on the adhesive layer side was peeled off from the laminated sheet obtained above, and the test was conducted by sticking to a size of 400 × 600 mm around the indenter on one side of the flat plate through the adhesive layer. Two bodies were made.
In addition, the punching test was carried out by using a universal material testing machine (model Model 5582) manufactured by Instron Japan Company Limited and applying a displacement in the vertical direction to the concrete indenter of the specimen. The loading speed was 1.0 mm / min, and the relationship between the displacement of the indenter in the vertical direction and the punching load was measured.
The test results are shown in Table 1.

  All the test bodies satisfied the load value (load value of 0.5 kN or more up to a displacement of 50 mm) required for the tunnel flaking preventing fiber sheet bonding work. Further, when the conventional fiber sheet is broken at a displacement of up to 50 mm and exhibits the maximum load, it was found that the protective sheet used in the present invention can withstand a displacement exceeding 50 mm.

  Although the present invention has been described with the embodiments so far, the present invention is not limited to these embodiments, and those skilled in the art can conceive other embodiments, additions, changes, deletions, and the like. It can be changed within the range, and any embodiment is included in the scope of the present invention as long as the effects of the present invention are exhibited.

DESCRIPTION OF SYMBOLS 1 Concrete box 1a Hollow part 2 Joint material 3 Protection sheet 3a Base rubber 3b Adhesion layer 3c Cover film 4 Space 5 Sealing material (sealing layer)
6 Drainage pipe 10 Concrete box continuous body 10a Connection joint 90 Cover member 91 Anchor bolt

Claims (9)

  A box culvert composed of a concrete box continuous structure which is formed by connecting concrete boxes having hollow parts penetrating so that the hollow parts communicate with each other, and filling joint material between the joints of the concrete boxes. A method for repairing a connection joint portion due to aging of the joint material in which a protective sheet in which an adhesive layer is laminated on a base material layer is coated on at least a ceiling portion of the connection joint portion, and the adhesive layer is covered with a concrete box A method for repairing a box culvert, characterized in that it is adhered or bonded to a concrete wall of the joint to prevent aged joint material, earth and sand, and moisture contained in the earth and sand from falling from the ceiling portion of the connection joint.   The protective sheet includes an ethylene propylene diene rubber, a chloroprene rubber, a styrene butadiene rubber, an acrylic rubber, a urethane rubber, a base material layer made of acrylic silicone rubber or silicone rubber, or a base material layer made of epoxy fiber reinforced plastic and silicone. The repair method of the box culvert of Claim 1 including a system adhesive layer, an acrylic adhesive layer, an acrylic silicone adhesive layer, or a urethane adhesive layer. The protective sheet is a base material layer made of silicone rubber having a hardness of 10 to 90 according to a durometer A hardness meter defined in JIS K 6249;
(A) an organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule;
(B) R ₃ SiO _1/2 unit (wherein R is an unsubstituted or substituted monovalent hydrocarbon group, but R contains an alkenyl group) and a resinous material mainly composed of SiO ₂ unit Polymer,
(D) an organohydrogenpolysiloxane containing at least two hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule;
(E) A cured product of an addition-curable silicone rubber composition or a silicone gel composition, wherein the cured product contains an addition reaction catalyst and has surface tackiness, and a silicone-based adhesive having an Asker C hardness of 1 to 60 The method for repairing a box culvert according to claim 2, comprising a layer.   The method for repairing a box culvert according to claim 1, wherein the protective sheet is transparent or translucent.   The box culvert repair method according to claim 1, wherein the protective sheet has a thickness of 0.5 to 8 mm.   The method for repairing a box culvert according to any one of claims 1 to 5, wherein the joint material is mainly asphalt.   A box culvert consisting of a continuous structure of concrete boxes is formed by connecting concrete boxes with hollow parts penetrating so that the hollow parts communicate with each other, and filling the joints between the concrete boxes with joint material. When covering, at least the ceiling part of the connection joint part is covered with a protective sheet in which an adhesive layer is laminated on the base material layer, and the adhesive layer is adhered or adhered to the concrete wall of the concrete box, A box culvert construction method characterized by preventing joint material, earth and sand from the ceiling portion of the earth, and falling and outflow of moisture contained in the earth and sand.   The protective sheet includes an ethylene propylene diene rubber, a chloroprene rubber, a styrene butadiene rubber, an acrylic rubber, a urethane rubber, a base material layer made of acrylic silicone rubber or silicone rubber, or a base material layer made of epoxy fiber reinforced plastic and silicone. The construction method of the box culvert of Claim 7 including a system adhesive layer, an acrylic adhesive layer, an acrylic silicone adhesive layer, or a urethane adhesive layer. The protective sheet is a base material layer made of silicone rubber having a hardness of 10 to 90 according to a durometer A hardness meter defined in JIS K 6249;
(A) an organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule;
(B) R ₃ SiO _1/2 unit (wherein R is an unsubstituted or substituted monovalent hydrocarbon group, but R contains an alkenyl group) and a resinous material mainly composed of SiO ₂ unit Polymer,
(D) an organohydrogenpolysiloxane containing at least two hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule;
(E) A cured product of an addition-curable silicone rubber composition or a silicone gel composition, wherein the cured product contains an addition reaction catalyst and has surface tackiness, and a silicone-based adhesive having an Asker C hardness of 1 to 60 The method for constructing a box culvert according to claim 8 including a layer.

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