JP2011179198A - Method for preventing exfoliation of concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing exfoliation of concrete, which can effectively fix a terminal end of an FRP net. <P>SOLUTION: In this method for preventing the exfoliation of the concrete, a net-like object, in which a thermoplastic resin mesh is fixed to the FRP net formed by being woven in a knotless manner with two pieces of net yarn and hardened, is fixed to a concrete surface by means of a fixing implement and an anchor. The fixing implement includes: a through-hole for the anchor in the center; a fitting portion capable of being fitted to at least one mesh (square) of the FRP net; outer edge walls provided so as to face side walls of the fitting portion; and a grasping groove provided between the side wall and the outer edge wall portion so as to hold the two pieces of net yarn. The fixing implement is fitted and inserted into the mesh in the predetermined region of the FRP net, while the anchor is driven (fixed) into the through-hole for the anchor. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for preventing concrete peeling in concrete structures such as concrete tunnels, elevated roadways, bridges, and buildings.

  In recent years, reinforced concrete structures at or near the coast are damaged by sea salt particles, or the structures deteriorate due to corrosion and expansion of the reinforcing bars caused by salt intrusion into reinforced concrete structures in contact with seawater. Or deterioration of concrete due to weakening of the surface layer due to substances that are harmful to concrete, such as acid rain and chemicals in factories, or excessive traffic to structures due to increased vehicle traffic, increased loading capacity, speeding up, etc. It is a big problem that the surface part of the concrete structure is peeled off due to load or the concrete structure itself is deteriorated.

Various methods for preventing the peeling of the deteriorated concrete, various methods for repairing the peeled portion, and materials thereof have been studied (for example, see Patent Document 1). Among them, in a repair or reinforcement mesh in which a laminate having a protective layer as a surface layer and an adhesive layer to a concrete structure in advance is provided, and a reinforcing layer made of a fiber base material is interposed between these layers, the fiber As a base material, one using a sheet-like material obtained by processing organic fibers or inorganic fibers into a nonwoven fabric or a woven fabric has been proposed as being able to facilitate construction and stabilize the quality (see Patent Document 2).
Further, as a net for preventing the concrete lump from peeling off and falling, a peeling prevention net has been proposed in which a metal net is sandwiched between metal frame bodies (see Patent Document 3).
Furthermore, a construction method (see Patent Document 4) is proposed in which a net body in which a rope is inserted and sewn around a synthetic fiber net is bound and stretched via a rope to a connecting wire inserted in a support fitting.

  Furthermore, in view of the above problems, a method for attaching a lightweight FRP lattice reinforcing member having a reinforcing effect similar to that of a reinforcing bar to corrosion with a concrete structure with an anchor bolt, an adhesive resin or the like has been proposed, and an improved attaching method thereof. Has been proposed (Patent Document 5).

  On the other hand, the present applicant uses long fibers impregnated with an uncured thermosetting resin as a mesh body of a mat for mats such as futon and potato, which are used in various civil engineering works with stone blocks inside. A mesh body (net-like body) having an arbitrary texture using an intermediate (uncured material) of a long fiber-reinforced synthetic resin linear material, the outer circumference of which is coated with a solidified thermoplastic resin Has been proposed, and this mesh body is heat-cured (see Patent Document 6). According to this mesh body, the drawbacks of conventional metal wires can be overcome.

JP 2003-269087 A JP 2002-256707 A Utility Model Registration No. 3068773 Japanese Patent Laying-Open No. 2005-179938 JP 2006-9266 A Japanese Patent Laid-Open No. 2003-184048

However, the repair method described in Patent Document 1 has problems such as a large amount of work, such as ground cleansing, primer treatment, unevenness correction, adhesive application, impregnation adhesion of reinforcing fiber sheet, top coating, and many processes. There is a point. Although patent document 2 is going to omit the impregnation adhesion | attachment process of a reinforced fiber sheet by making it into a sheet | seat, it has the following faults at the time of construction when there exists a tunnel joint part or water leakage.
That is, cracks or water leakage from the joints may occur in the vicinity of joints having a buffering function for concrete structures, such as joints on the lining concrete walls of tunnels. In this case, it is necessary to perform repairs to prevent peeling / peeling across the joints or repairs to prevent leakage by providing a water conduit.
As one of the repairing methods, when applying the sheet bonding method of the conventional method, the sheet is pasted so as to adhere to the entire surface to be repaired including the healthy layer. That is, after a primer serving as an adhesive is applied to the entire surface of the sheet, the sheet is pasted thereon to finish the sheet without any non-adhered portions.
However, the following problem occurs in such a method using full adhesion. That is, since the structure part that behaves differently at the joint part is included in the pasting range of the sheet, it is assumed that the sheet cannot follow such behavior after the pasting, and peeling or breaking occurs. It is difficult to maintain the expected repair performance and ensure durability. Further, the same problem occurs in the method of fixing a plate-like member other than the sheet bonding.
Therefore, it is possible to follow the different behavior of the structure part in the joint part, prevent the sheet from peeling and breaking, maintain the desired repair performance and ensure the durability As a repair method around the joint portion, a method of repairing by attaching a sheet to a concrete structure so as to straddle the joint portion is performed. However, this method is troublesome and takes a lot of work time.

Further, the peeling prevention net described in Patent Document 3 is made of metal and has a problem of occurrence of rust, and since it has a square planar shape, it is difficult to use for a concrete structure having a curved surface. For this reason, there are problems such as a small degree of freedom between the mounting hole and the fixing portion when fixing.
Further, the net body tensioning method disclosed in Patent Document 4 is intended to prevent concrete fragments from being peeled off from the lower surface of the road viaduct, and cannot be applied to the upper surface of a tunnel or a wall surface.
In addition, the FRP lattice described in Patent Document 5 is a comparison in which reinforcing bars are arranged in a lattice form with a spacing of 30 to 150 mm from each other, a width of 3 to 10 mm, a thickness of 1 to 5 mm, and planar rigidity. It is not suitable for stretching on a stepped portion because it is rigid. In addition, the weight is relatively heavy and expensive, and a problem remains in workability.

As described above, in the conventional net for preventing a concrete structure from peeling off, there are problems in terms of lightness, workability, level difference in a non-land area, workability in a spring area, price, and the like.
On the other hand, the net body of the FRP described in Patent Document 6 used for the straw mat and the like because of its light weight, corrosion resistance, and superiority in handling and work has a rigid straight line and flexibility such as FRP bars and steel wires. It has intermediate rigidity with the nylon mesh body and can be suitably constructed for the above-mentioned problems. That is, it is a net that suppresses the displacement of the concrete piece with respect to dropping, and is easily installed across the joint portion with the same number of anchors installed as the FRP bars.
However, since the FRP net is knitted in an unbounded manner, (i) if it is constructed with a conventional anchor at its end, the net thread of the net may be loosened when loaded, and the original strength may not be exhibited. For this reason, in order to ensure the net strength more reliably at least from the end to the inside of the first mesh, the anchor must be fixed to the inner side of the second mesh. (ii) FRP net joints will inevitably occur in construction, but as shown in Fig. 15, when anchoring is performed on the inner side of the second mesh and the net is constructed by butt-joining at the joint, the connection zone between the two FRP nets At T2, the end of the FRP net is in a cantilever state, and the FRP net does not have sufficient planar rigidity to hold the peeled concrete piece, so that a small piece of concrete may fall between them. In order to eliminate the cantilever state, if it is attempted to solve the problem by fixing by overlapping, it is necessary for the overlapping part to hold the FRP net double, and it is complicated to perform the anchor construction accurately. I don't get it. In addition, it is conceivable that the end of the mesh thread of the FRP net is precisely machined so that the mesh thread is not loosened and fixed at the endmost mesh, but the cost of the FRP net is reduced due to the terminal machining. Rising and impractical.
Under such circumstances, there has been a demand for a concrete peeling prevention method that can be effectively fixed at the mesh of the terminal of the FRP net.

  Therefore, in the present invention, it is possible to fix a net-like object composed mainly of an FRP net that is knitted and cured in a knotless shape, and a mesh made of thermoplastic resin, to the concrete surface at the end of the net. As a result of earnestly examining concrete peeling prevention methods, it is provided in the center facing the through hole for the anchor, a fitting part that can be fitted into at least one mesh (mesh) of the FRP net, and the side wall of the fitting part The above-mentioned problem can be solved by using a fixing tool that is provided between the outer edge wall and the side wall and the outer edge wall portion and has a holding groove for holding the mesh thread of the two children. I found it.

That is, the present invention
(1) Concrete in which a net-like material in which a mesh made of thermoplastic resin is fixed to an FRP net that is knitted in a knotless shape with two mesh yarns and hardened is fixed to a concrete surface by a fixture and an anchor. A peeling prevention method,
(I) The FRP net is a knotless net having a mesh (mesh) knitted into a square of 30 to 150 mm,
(ii) The thermoplastic resin mesh is fixed to the surface of the FRP net on the concrete structure side, and is 1/3 or less of the mesh (mesh) of the FRP net and has a square mesh of 1 to 30 mm. (Mesh)
(Iii) The fixture has an anchor through hole in the center;
A fitting portion capable of being fitted into at least one mesh (mesh) of the FRP net;
An outer edge wall provided facing the side wall of the fitting portion;
A holding groove provided between the side wall and the outer edge wall portion for holding the mesh thread of the two children;
(Iv) Insert the anchor into the mesh of a predetermined part of the FRP net, while placing (fixing) an anchor in the anchor through hole,
And (2) fixing the FRP net at the end of the FRP net at the end of the mesh having an extra length of 10 mm to 1/2 of the mesh at the end, The concrete peeling prevention method according to (1), which is fixed at a predetermined interval by the fixing tool and the anchor,
Is to provide.

The concrete peeling prevention method of the present invention uses a specific fixing tool for fixing a net-like object mainly composed of an FRP net formed by knitting a net with two mesh yarns and curing it. When loading onto the FRP net due to peeling, the load is not concentrated on the crossing part (no-knot part) of one mesh thread, and the fitting part of the fixing tool is connected via at least one side or two sides of the mesh. And / or because the load is applied to the outer edge wall, the anchor pin finally applies a concentrated load to the intersection of one mesh thread to unwind the mesh thread in the conventional manner, and the net structure is destroyed. Alternatively, the phenomenon that the net yarn is cut at the crossing portion of the net yarn is prevented.
For this reason, it is possible to effectively prevent the concrete from peeling off by fixing the concrete surface to the concrete surface with the anchor at the end of the mesh of the FRP net.
Therefore, the FRP net can be fixed at the end of the mesh of a predetermined size. Therefore, in the construction of the FRP net, the necessity of overlay connection and the overlay that are conventionally required when constructing inside the second mesh are performed. Problems such as fear of falling concrete pieces due to the cantilevered state of the end of the FRP net when not performed are solved.
According to the concrete peeling prevention method of the present invention, since the end portion of the FRP net can be butt-constructed, it is possible to simplify the construction, shorten the construction time, and reduce the FRP net material cost.

It is a schematic diagram which shows the state which fixed the terminal side of the FRP net to the concrete structure in the concrete peeling prevention method of this invention. In the concrete peeling prevention method of the present invention, a state in which a fixing device of a preferred embodiment is fitted and applied to an FRP net knitted into a knotless shape of a corner is shown, (A) a plan view, (B) X- It is X 'line sectional drawing. In the concrete exfoliation preventing method of the present invention, (A) a bottom view, (B) XX ′ showing a state in which the fixing device of a preferred embodiment is fitted to an FRP net knitted into a square knotless shape. It is a line sectional view and (C) YY 'line sectional view. The state which fitted and constructed the fixing tool of the other embodiment used for the peeling prevention method of this invention on the FRP net is shown, (A) Top view, (B) Bottom view, (C) XX 'line cross section FIG. It is a perspective view of the fixture of the preferred embodiment used for the Example. It is a perspective view of the fixing tool of another aspect. It is explanatory drawing of the net-like thing used for the peeling prevention method of this invention, (A) A block diagram, (B) The elements on larger scale. Explanatory drawing of a FRP net. It is a schematic cross section which shows the structure of the mesh thread (composite linear object) which comprises an FRP net. It is explanatory drawing of the full-scale loading test method of a FRP net, (A) Bottom view, (B) It is explanatory drawing of the deformation | transformation condition of the FRP net in the progress of a loading test which shows the state at the time of a loading test start. . It is explanatory drawing of the terminal fixing method of the FRP net | network of the test example in a full-scale loading test. It is explanatory drawing of the terminal fixing method of the FRP net | network of the comparative test example in a full-scale loading test. It is a load (kN) -displacement (mm) curve of Example 2 by a full-scale loading test. It is a load (kN) -displacement (mm) curve of the comparative example 2 by a full-scale loading test. It is a load (kN) -displacement (mm) curve of the comparative example 4 by a full-scale load test. It is explanatory drawing of the state which carries out the tension test in the diagonal direction of the mesh | network of a FRP net | network with the fixing tool used for this invention. It is explanatory drawing of the state which carries out the tension test in the diagonal direction of the mesh | network of a FRP net with the conventional fixing tool. It is a schematic diagram which shows the state which fixed the terminal side of the FRP net to the concrete structure in the conventional concrete peeling prevention method.

  Hereinafter, preferred embodiments of the present invention will be described. Each embodiment shown in the accompanying drawings shows an example of a typical embodiment according to the present invention, and the scope of the present invention is not interpreted narrowly.

The concrete peeling prevention method of the present invention is a method of fixing a net-like material in which a thermoplastic resin mesh is fixed to an FRP net that is knitted in a knotless shape with two mesh yarns and cured, and a specific fixture. It is characterized by being fixed to the concrete surface with an anchor. The FRP net constituting the net-like material used in the concrete peeling prevention method of the present invention is a knotless net having a mesh (mesh) knitted into a square of 30 to 150 mm. The mesh made of thermoplastic resin is fixed to the surface of the FRP net on the concrete structure side, and is 1/3 or less of the mesh (mesh) of the FRP net and 1-30 mm square mesh (mesh). have.
In addition, the fixture includes an anchor through-hole in the center, a fitting portion that can be fitted into at least one mesh (mesh) of the FRP net, an outer edge wall provided to face the side wall of the fitting portion, A holding groove is provided between the side wall and the outer edge wall portion to hold the two mesh threads.
Further, in order to fix to the concrete surface with the fixing tool and the anchor, the fixing tool 1 is inserted into a mesh of a predetermined part of the FRP net 20 as shown in FIG. The anchor 8 may be driven (fixed).
Hereinafter, the concrete peeling prevention method of the present invention will be described in detail.

[Net-like]
FIG. 7 shows a net-like material used in the concrete peeling prevention method of the present invention, and the net-like material is composed of an FRP net 20 and a thermoplastic resin mesh 30. The FRP net and the thermoplastic resin mesh (hereinafter sometimes simply referred to as “mesh”) 30 are fixed to each other. The means for fixing is not particularly limited, and the FRP net and the mesh are bonded to each other by, for example, an adhesive or heat-sealing at a mesh yarn connecting portion (entangled portion) 25 in FIG. 7B. Alternatively, a method of fixing with a binding fastener, a thin string, or the like at an appropriate interval may be used. Since the mesh is usually lower in strength than the FRP net, in actual construction, it is installed between the FRP net and the concrete surface, so it is not necessary to be fixed to the entire surface of the FRP net. What is necessary is just to adhere to the grade which the handling at the time of construction is easy.

[FRP net]
As shown in FIG. 8, the FRP net used in the concrete peeling prevention method of the present invention needs to be knitted without a knot at the connecting portion 25 where the mesh 21 intersects. Is a non-cured knitted net having flexibility, and is cured after the knitted net.
FIG. 9 is a schematic cross-sectional view of a cured composite linear object (hereinafter simply referred to as “composite linear object”) constituting the FRP net 20 according to the present invention. The code | symbol 21 of FIG. 9 has shown the composite linear object which consists of a fiber reinforced synthetic resin. The composite linear material 21 includes a long fiber 22, an uncured thermosetting resin 23 ′ that may include a thickener and a penetrating thickening ratio blended as necessary, and a solidified thermoplastic resin. 24 is an uncured composite linear product 21 ′ that is heat-cured. The long fibers 22 are impregnated with an uncured thermosetting resin 23 ′, and the outer periphery thereof is covered with a thermoplastic resin 24.
The FRP net 20 includes, for example, a step of adding a thickener and a penetrating thickener to the uncured thermosetting resin 23 ′ as necessary, and the long fibers 22 into the uncured thermosetting resin 23 ′. An impregnation step, an outer periphery of the impregnated long fiber 22 is coated with a thermoplastic resin 24 to form an uncured composite linear material 21 ′, and this is wound around a bobbin or the like; A knotless net using a braided composite linear article 21 'and a step of thermosetting the uncured thermosetting resin of the uncured composite linear article 21' through a cured composite By setting it as the linear thing 21, it can be set as the FRP net | network 20 provided with the predetermined shape and physical property.
The outer diameter of the composite linear object 21 is preferably 1.5 to 5 mm, and more preferably 1.8 to 2.5 mm. If it is less than 1.5 mm, sufficient tensile strength as a concrete peeling prevention net cannot be obtained, and if it exceeds 5 mm, it becomes difficult to form a knitted net, and the resulting FRP net 20 is also inflexible and increases in weight. Problems with workability arise.
Further, the breaking load (tensile strength) of the composite linear object 21 constituting the FRP net 20 is preferably 400 N or more from the viewpoint of performance as a concrete peeling prevention net, more preferably 500 N or more, and 600 N The above is particularly preferable.

  In the composite linear object 21 according to the FRP net of the present invention, when the uncured composite linear object 21 ′ is heat-treated, the uncured thermosetting resin 23 ′ has a high viscosity and is gelled. It is desirable not to. Since the uncured curable resin 23 'is gelled, the physical properties are likely to change as time passes.

  The type of the long fiber 22 as the reinforcing fiber used in the present invention is not particularly limited, and synthetic fiber such as polyolefin fiber and polyester fiber, inorganic fiber such as glass fiber, metal fiber, and the like can be used. It is preferably a synthetic resin fiber, and more preferably a polyester long fiber.

  Further, the fineness of the long fibers 22 is not particularly limited, and can be appropriately selected in consideration of the purpose of use and ease of processing. Moreover, the volume content of the fiber of the FRP part in the composite linear material 21 is not particularly limited, but is generally 30 to 70 Vol. The volume content of the long fiber as the reinforcing fiber can be appropriately selected in consideration of desired physical properties depending on the purpose of use of the net (use part of the net for preventing peeling).

  The (uncured) thermosetting resin 23 ′ used in the present invention is not particularly limited as long as it can be cured by heating, and preferably has excellent performance stability after curing. An unsaturated polyester resin, an unsaturated alkyd resin, an epoxy resin, or the like is desirable, more preferably a crosslinkable substance is contained, and more preferably, an unsaturated polyester resin, an unsaturated alkyd resin, or an epoxy acrylate is used. It is desirable to contain at least one, a crosslinkable substance such as a crosslinkable monomer, and a polymerization initiator such as diacyl peroxide. By setting it as such a mixing | blending, a polymerization reaction can be accelerated | stimulated with the heat | fever etc. at the time of heat processing.

  The kind of the thermoplastic resin 24 for coating used in the present invention is not particularly limited, but is preferably a material having excellent flexibility, and a polyolefin resin or the like can be preferably used. In addition, when the uncured thermosetting resin 23 ′ contains a crosslinkable substance, it is desirable that the uncured thermosetting resin 23 ′ has a property of being hardly eroded by the crosslinkable substance or the like. More preferably, the durability of the FRP net can be improved by using a material that does not easily wear. In the present invention, the combination of the long fibers 22, the uncured thermoplastic resin 23 ', and the thermoplastic resin 24 is not particularly limited.

FIG. 8 shows an FRP net 20 using the composite linear object. The FRP net 20 shown in the figure is a knotless network without a knot at the connecting portion 25. If the mesh yarn composed of the uncured composite linear material 21 'is a double-filament, and a knotless net is knitted, the mesh is accurate, the connecting portion 25 is flat, and the concrete peeling prevention net is made of concrete. Even if it is attached to the surface of the structure, it is flat and attractive.
In a knotless net, two mesh yarns cross each other, and the mesh yarn penetrates through the connecting portion and extends in a straight line (ordinary type). Crossed three times, zigzag, where the net yarn stretches in a zigzag manner, crosses the child yarn of two mesh yarns 3-4 times, the net yarn stretches linearly through the connecting part, and the shape when the mesh is opened is six A square-shaped turtle shell type is mentioned, but in particular, since it is lightweight and has a uniform mesh, it is preferable to use a penetrating type (ordinary type) non-knotted net knitted into a square.

  At the stage where the knotless net is produced by the knitting machine, the mesh can be opened in a rhombus shape or a square shape, but the FRP net 20 used in the present application is opened in a square shape after the knitting network. In this state, it is supplied into a vacuum kettle to cure the uncured thermosetting resin and heat set (fix) the square net shape.

With respect to the mesh of the FRP net 20 used in the present invention, in the present invention, the distance between the opposing mesh yarns constituting the mesh is defined as the mesh, and the distance W of the opening is defined as the mesh. The mesh W (26) of the FRP net needs to be 30 to 150 mm in size, and the mesh is considered in this range as the strength of the composite linear object 21, the strength of the mesh 30 used in combination, and the like. However, when the composite linear object 21 having an outer diameter of 2.1 mm is used, the 50 mm square is particularly preferable in view of balance with the flexibility of the FRP net 20 and the like.
In addition, the width of the FRP net is determined by the relationship with the knitting netting machine, and the maximum length of the FRP net is about 4m, and the length of the FRP net is about 18m. Corresponding to the construction method, etc., it can be supplied as an appropriate width and length.

[Thermoplastic resin mesh]
The thermoplastic resin mesh used in the concrete peeling prevention method of the present invention has a mesh knitted into square corners like the FRP net, the mesh is 1/3 or less of the FRP net, and 1 to 30 mm. It is preferably 1 to 20 mm, more preferably 2 to 10 mm. If the mesh size is less than 1 mm, clogging may occur due to the peeled small pieces, which may lead to poor water permeability, making it difficult to find new cracks in the concrete, and if it exceeds 30 mm, the stripped pieces cannot be captured effectively.
Examples of the thermoplastic resin for the mesh include polyester, vinylon, nylon, polyethylene, polypropylene, aramid, vinyl chloride, and acrylic. Specific examples of the thermoplastic resin net-like material include a polyester net, a vinylon fiber net, a nylon fiber net, and a polyolefin yarn net.

Also, a sheath component of a sheath-core composite fiber composed of (a) a core component made of a polyolefin resin and (b) a sheath component made of a polyolefin resin having a melting point 20 ° C. lower than the melting point of the core component is fused. It may be a biaxial mesh product (trade name “Simmesh”, manufactured by Ube Nitto Kasei Co., Ltd.) formed by weaving a sea-island type composite yarn. In this biaxial mesh-like material, since the sea-island type composite yarn is flat, it is unavoidable that a natural twist is added in the process of winding it around a bobbin or the like and the process of weaving, so that a partially twisted part is present. Although it is not, it is a plain weave biaxial mesh-like product composed of substantially flat warp and weft.
The fineness of the sea-island type composite yarn is 1000 to 2000 dtex, preferably 1500 to 2000 dtex, more preferably 1700 to 1900 dtex, from the viewpoint of ease of weaving a biaxial mesh and the strength of the mesh. Is desirable. Further, a material obtained by heat-sealing the intersection of a warp and a weft made of sea-island type composite yarn is preferable because there is no misalignment.

[FRP net and thermoplastic resin mesh]
In the concrete peeling prevention method of the present invention, as a net-like object, as shown in an enlarged view of one mesh in FIG. 7B, the FRP net 20 and the mesh 30 are, for example, the connecting portion 25 of the FRP net 20. It is necessary to be fixed on the contact side with the mesh 30 or the like. The purpose of fixing is to first integrate the FRP net 20 and the biaxial mesh-like object 30 to improve handling at the time of manufacturing, storage and construction, and simultaneously cover the opening 26 of the FRP net 20. In the unlikely event that concrete peels off the mesh 30, the load from the concrete strips is applied to the FRP net 20 via the composite linear object 21 in the vicinity of the load portion constituting the FRP net 20, and The load can be shared with the concrete structure through a member for fixing the FRP net 20, and the mesh 30 of the load part is prevented from bulging out from the mesh (opening) 26 of the FRP net 20 as much as possible. It is for suppressing.
As a specific fixing means, as already described, for example, the connecting portion (entangled portion) 25 of the net yarn is adhered by an adhesive or heat fusion, or at an appropriate interval with a binding fastener or a thin string. A fixing method may be used. Since the mesh is usually lower in strength than the FRP net, in actual construction, it is installed between the FRP net and the concrete surface, so it is not necessary to be fixed to the entire surface of the FRP net. What is necessary is just to adhere to the grade which the handling at the time of construction is easy.

In the case of using the biaxial mesh-like material, heat fusion is simple as a fixing means. Since the composite linear material 21 constituting the FRP net 20 has a thermoplastic resin coating 24, the thermoplastic resin coating 24 is used as the sea component of the sea-island composite yarn constituting the biaxial mesh-like material 30. A material that can be heat-sealed with a polyolefin resin is selected, and the FRP net 20 and the biaxial mesh-like material 30 are stacked and heat-sealed by a method such as passing through a heated roller heated to a temperature near the melting point. it can.
When this method is used, it is economically advantageous compared to the method using an adhesive because no adhesive is required, no application or curing device or labor is required.

The net-like material used in the concrete peeling prevention method of the present invention may be subjected to various treatments as necessary after the production stage of the FRP net, the mesh production stage such as biaxial mesh-like material, or the combination thereof. good.
For example, antioxidant treatment, weather resistance treatment, antibacterial treatment, flame retardant treatment, antistatic treatment, surface unevenness treatment, oxidation treatment, fine particle application treatment, water repellency treatment, oil repellency treatment, adsorption treatment, porous treatment, phosphorescence / fluorescence treatment Etc. can be applied. Examples of the surface unevenness treatment include a sand blast method and a solvent treatment method. Examples of the adhesion improving treatment include corona discharge treatment, plasma treatment, chromic acid treatment (wet), flame treatment, hot air treatment, and ozone / ultraviolet irradiation treatment.
Examples of the flame retardant treatment include those treated with a non-halogen flame retardant, a bromine compound, and the like. Specifically, an aromatic bromine compound, an alicyclic bromine compound, an aliphatic bromine compound, Inorganic metal hydroxide, inorganic metal oxide, inorganic metal carbonate, boric acid compound, sulfur compound, phosphate ester compound, ammonium polyphosphate compound, (iso) cyanuric acid derivative compound, cyanamide compound, urea series Examples include drugs containing compounds.

〔Fixture〕
As shown in FIG. 5, the fixing tool used in the concrete peeling prevention method of the present invention has an anchor through hole 2 in the center and a fitting portion 3 that can be fitted into at least one mesh (a mesh) of the FRP net. And an outer edge wall 5 provided to face the side wall 4 of the fitting portion 3, and provided between the side wall 4 and the outer edge wall portion 5 for holding the mesh thread of the two children The holding groove 6 is provided. The fitting portion 3 may have a fitting portion that can be fitted to the first mesh in the case of fixing to a concrete structure at the end of the net-like material. When fixing a part etc., it is good also as a structure which has five fitting parts which can be fitted to 5 meshes, and the number of fitting parts is not specifically limited.
The shape of the fitting portion is preferably an external shape that approximates the mesh shape of the FRP net from the viewpoint of ease of fitting to the FRP net, and the corners of the side walls are rounded or chamfered. Processing etc. may be given.
In FIG. 6, the fitting portion 3 is square and includes four outer edge wall portions 5, four holding grooves 6, and island portions 7. The cross-sectional dimension of the holding groove 6 needs to be a dimension that can store at least two mesh yarns, and is preferably about twice the outer diameter of the mesh yarn 21 of the FRP net.

  In addition, normally, the square-shaped knotless net is in a swollen state due to the entanglement of the intersecting yarns at the connecting portion, so that the holding wall 6 of the fitting portion 3 and the holding groove 6 of the outer edge wall 5 are formed. The facing side is preferably chamfered (cut) as shown in FIGS. 3 (A) and 4 (B). If such a process is performed, it is possible to fit onto the net without difficulty including the connecting portion. 5 has four outer edge walls 5. However, the outer edge wall does not necessarily have to be opposed to all the side walls 4, and is attached to the mesh thread 21 of the FRP net. It suffices to be present at a site where the load is likely to be applied. However, if an outer edge wall is provided only at a specific position, the mounting direction of the fixture is specified at the time of concrete peeling prevention construction, so it may be complicated to check the mounting direction at the time of actual construction. It is preferable to have the same number of outer edge walls corresponding to the side walls.

FIG. 6 is a perspective view of another embodiment of the fixture 12 used in the present invention.
Compared with the fixture 11 shown in FIG. 5, there is a feature in that four island portions 7 are provided outside the holding grooves 6 that intersect each other. The size of the island is determined according to the thickness of the outer edge wall, but is determined according to the material used for the fixture and the assumed load on the net. Such an island is particularly effective when a material having a high breaking strength such as metal or FRP is selected as the material of the fixture.
Further, as shown in FIG. 4 (C), for example, as shown in FIG. 4 (C), a concave portion (a counterbore hole) having a depth that can be stored so that the head portion of the anchor does not protrude upward. ) Provides an effect that the finish after the anti-peeling work can be made beautiful.

Examples of the material of the fixture 1 include engineering plastic, steel plate, stainless steel, titanium, brass, and aluminum. From the durability after construction, it is selected from materials having rust resistance, corrosion resistance, weather resistance, water resistance, waste gas resistance, etc. and having the required strength. Examples of the process for manufacturing the fixture include a method of cutting a plate-like material, pressing a thin plate material, molding a metal material, and molding an engineering plastic material, In particular, the production method is not limited.
Of these fixing tool materials and manufacturing (processing) methods, it is preferable from the viewpoint of processing cost to form engineering plastics by injection molding.
Further, engineering plastics include ABS (acrylonitrile-styrene-butadiene resin), PBT (polybutylene terephthalate resin), PA (polyamide resin), PET (polyethylene terephthalate resin), AAS (acrylonitrile-styrene-acrylate resin), ACS ( One kind selected from chlorinated polyethylene-acrylonitrile-styrene resin) and AES (acrylonitrile-ethylene-styrene resin) or a mixture thereof is particularly preferable from the viewpoint of physical properties and ease of processing.

In the concrete exfoliation preventing method of the present invention, a fixing tool is inserted into a mesh of a predetermined portion of the FRP net, and an anchor is placed (fixed) in an anchor through hole of the fixing tool.
The predetermined part of the FRP net-like object into which the fixing tool is inserted is, for example, the mesh of the part corresponding to the interval specified by the construction standard, the FRP net and the thermoplastic resin mesh near the end of the FRP net. Say the mesh to fix.
The fixing of the net-like object at a predetermined portion of the FRP net is performed by the fixing tool and the anchor at the end of the FRP net having the extra length of 10 mm to 1/2 of the net. It is particularly preferable that the fixed net-like object is fixed on the entire surface because the area (T2 in FIG. 18) of the unfixed portion between the net-like objects can be reduced when the net-like object is applied to the entire surface. .

〔anchor〕
The anchor that can be used in the present invention is not particularly limited, and various types of anchors are used. For example, as shown in FIG. 2B, the cracked foot C of the anchor 8 expands when driven. Expandable anchor bolts are commonly used.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention, this invention is not limited to these Examples.

(Manufacture of uncured mesh yarn)
Production Example 1
14300 total dtex polyester long fibers (trade name “E1100T190-H02” manufactured by Toyobo Co., Ltd.) made of 1100 dtex / 13 non-twisted yarns and unsaturated polyester resin (manufactured by Nippon Yupica Co., Ltd., trade name) "Iupica 9001") is impregnated as an uncured thermosetting resin, and an uncured material is drawn and drawn to an outer diameter of 1.05 mm. Subsequently, the uncured material is guided to the head portion of the melt extruder, The outer periphery is covered with a polyethylene-based thermoplastic resin (trade name “NUCG5350”, manufactured by Nihon Unicar Co., Ltd.) in an annular shape, led to a water cooling tank, and the thermoplastic resin coating layer is cooled and solidified to form an uncured mesh yarn. (Composite linear object) was wound around a bobbin. The resulting uncured composite linear product had a diameter of 2.11 mm.

[FRP net production example]
Using the uncured composite linear material obtained in Production Example 1 (stored at 24 ° C. after production and passed for 1 day (24 hours)), a knotless net having a mesh size of 50 mm is knitted, and then Was heat-set while being cured in a vacuum pot at 100 to 120 ° C. by tensioning both ends so as to have a square shape of 50 mm, to obtain an FRP net.
The obtained FRP net had a unit weight of 640 g / m ² and an apparent thickness of 4.8 mm.
The composite linear material constituting the FRP net was unwound from the FRP net and measured for a sample. As a result, the outer diameter was 2.11 mm, the unit weight was 4 g / m, and the breaking load was 1080 N.

[Production example of sea-island type composite yarn]
Isotactic polypropylene (mp = 163 ° C.) is used for the core component, and linear low density polyethylene (mp = 110 ° C.) using a metallocene catalyst is used for the sheath component, and a conventional composite spinning equipment, core-sheath type composite spinning nozzle (240 Hole), spinning at 260 ° C. so that the sheath / core cross-section ratio is 35/65, and guiding to a stretching apparatus that is directly connected, and stretching at a stretching ratio of 13 times under a saturated water vapor pressure of 0.42 MPa and 145 ° C. To obtain a sea-island type composite yarn having a total fineness of 1850 dtex in which the fibers are fused with the sheath component along with drawing and having 240 filaments, using the core component polypropylene as the island component and the sheath linear low-density polyethylene as the sea component. (Spin draw method). Since this sea-island type composite yarn was drawn between rollers, 240 fibers were converged, and the yarn had a flat shape.
The sea-island composite yarn, which is this organic fiber reinforced thermoplastic resin composite, has a tensile strength of 6.5 cN / dtex, an elongation of 15%, a Young's modulus of 92.0 cN / dtex, and heat shrinkage measured at 140 ° C. The rate was 6.8%.

[Production example of biaxial mesh]
The obtained sea-island type composite yarn was woven into a plain weave using a loom so that warp and weft yarns were each placed at a center distance of 3 mm (injection density: 7 to 9 yarns / 2.5 cm). A shaft mesh was obtained. This plain weave biaxial mesh-like product was contact-heated with a heating roller having a surface temperature of 150 ° C. to melt the sea part resin of the composite yarn, thereby obtaining a biaxial mesh-like product in which the sea-island type composite yarn was thermally fused. The mesh-like product obtained after the thermal fusion had a mesh size of 3 mm, an opening of about 2 mm square, the intersection was thermally fused, and there was no misalignment. In addition, the adhesive strength of the intersection measured according to JIS standard R3420: Glass fiber general test method 7.4 was 7.3 N / 50 mm.

[Production example of net-like material]
The upper surface of the FRP net obtained as described above and the lower surface of the biaxial mesh-like product are contact-heated with a heating roller having a surface temperature of 150 ° C., respectively. The surface part of the sea part resin of the sea island type composite yarn of the shaft mesh-like material is melted, superposed, passed through a pressure roller, and the FRP net and the biaxial mesh-like material are heat-sealed. A net for preventing peeling was obtained.
Thermal fusion has been performed at the connecting portion of the FRP net (intersection of mesh yarn).

(Measurement of net softness)
A sample having a length of 24 cm and a width of 5.5 cm was prepared so that the four meshes included, and the bending resistance was measured by the amount of deflection according to the cantilever method of JIS L 1096 in the state of (A) the front surface and (B) the back surface. The amount of deflection at the tip when a load of 24 g is applied to the tip is 5.5 mm when the mesh-like object is measured as the upper surface, and the deflection amount when the mesh-like object is used as the lower surface is 7.8 mm. As a result, less deflection was obtained. This is presumably because the tensile stress acting surface with respect to the bending load becomes a mesh-like surface, and the reinforcing effect on the FRP net is expressed.
Even if it is actually constructed as a concrete peeling prevention net, it is prepared (temporary) in the direction of interposing a mesh-like object on the concrete structure side from its usage, and fixed to the concrete structure, so there is less deflection Is convenient and the work efficiency is improved.

(Full-scale loading test of net-like objects)
With respect to the net-like material obtained above, the relationship between the fixed portion near the end of the FRP net in the net-like material and the load and displacement amount was measured using the fixture specified in the present invention and the conventional fixture.
In the full-scale loading test, as shown in the bottom view of FIG. 10 (A), a rectangular hole is provided in the center of the concrete flat plate 40, and the size of the FRP net by the effective mesh of the net-like object is determined in the longitudinal direction of the hole. 650 mm (13 mesh) and 600 mm (12 mesh) in the direction orthogonal to the longitudinal direction, the test was performed by changing the type and fixing position of the fixture.
In the embodiment as a fixture, a through hole 2 having a diameter of 6 mm in the central portion, a fitting portion 3 having a height of 40 mm and a height of 5 mm, four outer edge walls 5 having a height of 5 mm and a diameter of 5 mm and a circumference of 5 mm, and a width The holding groove 6 having a depth of 10 mm and a depth of 5 mm, a size of 70 × 70 mm and an overall thickness of 10 mm, and the perspective view shown in FIG. 5 was used. An anchor having a diameter of 6 mm was used.
In the comparative example, a disk-shaped washer with a diameter of 70 mm and an anchor with a diameter of 6 mm were used and fixed at four points as shown in FIG. The loading was performed using a H-shaped steel having a width of 100 mm and a length of 700 mm at a speed of 50 mm / min, and a load (kN) -displacement (mm) curve was recorded. In addition, about the positional relationship of a fixing tool, about Example 1 and 2, it shows to FIG. 11 (A), (B) and about Comparative Test Examples 1-4, it shows to FIG. 12 (A)-(D). In addition, illustration of the thermoplastic mesh 30 is abbreviate | omitted in FIG.11 and FIG.12.

Examples 1 and 2 and Comparative Examples 1 to 4
(Results of full-scale loading test of net-like objects)
Table 1 summarizes the results of the examples and comparative examples. Moreover, the load-displacement curve in the full-scale loading test of Example 2, the comparative example 2, and the comparative example 4 is shown FIGS.

As shown in Table 1, in Examples 1 and 2 of the concrete peeling prevention method of the present invention, compared to Comparative Examples 1 and 2, the Examples are 1.9 times to 1. The load is five times higher. Moreover, in an Example, the displacement at the time of a maximum load is also larger than the comparative examples 1 and 2, and it is suggested clearly that the capture | acquisition capability of a concrete peeling piece is high. On the other hand, in Comparative Examples 3 and 4 in which the fixed mesh position is shifted from the outermost end to the second mesh, the maximum load and the displacement at the maximum load are increased. This is because the extra length (including the length of the ear and the mesh) is increased, and a load greater than that of Comparative Examples 1 and 2 is required to unwind the twin mesh yarn. As described above, if the fixed mesh position is shifted inward, a high maximum load can be secured. However, if such a construction is performed specifically, as shown in FIG. 18, the connecting portion T2 of the FRP nets in the two net-like objects. , The leading edge of the FRP net or the net-like object is in a cantilever state. For example, in Comparative Example 4, a 150 mm connecting portion (blank portion with a peeling prevention function) is generated, and the concrete passes through this portion. The fall of the piece cannot be prevented.
On the other hand, in the first embodiment, the connecting portion T1 shown in FIG. 1 can be 20 mm, and in the second embodiment, it can be 50 mm. Therefore, compared with the comparative example, the blank portion of the peeling prevention function can be extremely reduced. Further, in order to completely prevent the fallen pieces of concrete from being peeled off, a large load is not applied at the joint portion, so that only a thermoplastic resin mesh may be applied.

Example 3 and Comparative Examples 5-6
(Tension test in the diagonal direction of the mesh of the FRP net in the net-like material)
Since the tensile force in various directions acts on the fixed net-like FRP net depending on where the concrete is peeled off, the fixing tool used in the peeling prevention method of the present invention (the same as in Example 1) and Using a conventional fixture, the fixing position was changed, and the maximum load when the tensile force in the diagonal direction of the FRP net in the net-like portion was applied was measured.

FRP net [50 mm mesh (mesh 45 mm)] knitted into a square in the net-like material obtained in the production example is cut into 300 mm length and 300 mm width (6 mesh) as shown in FIGS. Then, this net-like object was fixed to the upper and lower gripping tools made of a steel plate having a thickness of 5 mm using a predetermined fixing tool, and the through hole of the fixing tool was fixed with a screw. In addition, illustration of the thermoplastic mesh 30 is abbreviate | omitted in FIG.16 and FIG.17.
The tensile test was performed at a speed of 50 mm / min with a universal tensile tester (Orientec Co., Ltd .: TENSILON universal tester RTA-100).
The results are shown in Table 2.

According to the results of the tensile test in the diagonal direction of the mesh, the tensile stress acts on the diagonal intersection of the mesh, and the resistance to unwinding of the two mesh yarns changes depending on the length of the extra length, which affects the maximum tensile strength. It was confirmed that
In Comparative Example 5 using a conventional fixing tool, when it is fixed at the outermost mesh, only 0.39 kN, which is about 30% of the strength of the original mesh, is exhibited. On the other hand, as shown in Comparative Example 6, if the second mesh from the end is fixed, the tensile strength is increased. However, as described above, it is inevitable that the connecting portion is widened, and there is a blank portion with a peeling prevention function. Arise.
On the other hand, in Example 3 using the fixing tool used in the present invention, a tensile strength of 1.27 kN was obtained even with fixing at the endmost mesh, and with the second stitch from the shortest using the conventional fixing tool. It was confirmed that the tensile strength was comparable to that of the comparative example 6 that was fixed, and could exhibit a tensile strength equal to or greater than that of the net yarn.

The concrete peeling prevention method of the present invention can effectively prevent the concrete from peeling off by fixing it to the concrete surface with an anchor at the end of the mesh of the FRP net. It can be effectively used as an improved concrete peeling prevention method that can solve the problems such as overlapping and connecting, and the fear of falling concrete pieces at the end of the FRP net when the overlapping is not performed.
In the concrete peeling prevention method of the present invention, the end part of the FRP net can be butt-assembled, so it can be effectively used as a concrete peeling prevention method capable of simplifying the construction, shortening the construction time, and reducing the FRP net material cost. it can.

DESCRIPTION OF SYMBOLS 1 Fixing tool 2 Through-hole 3 Fitting part 4 Side wall 5 Outer edge wall 6 Holding groove 7 Island part 8 Anchor 9 Countersink hole 10 Net object 11, 12, 50 Fixing tool 20 FRP net 21 Mesh thread (composite line shape) object)
21 'uncured mesh yarn 22 long fiber 23 cured thermosetting resin 23' uncured thermosetting resin 24 thermoplastic resin 25 articulated part (entangled part)
26 Mesh 30 Thermoplastic resin mesh 31 Mesh yarn 40 Concrete flat plate 41 H-shaped steel W Mesh size

Claims (2)

Concrete peeling prevention method for fixing a net-like material in which a mesh made of thermoplastic resin is fixed to an FRP net formed by knitting a net with two meshes and cured and fixed to a concrete surface with a fixture and an anchor Because
(I) The FRP net is a knotless net having a mesh (mesh) knitted into a square of 30 to 150 mm,
(Ii) The thermoplastic resin mesh is fixed to the surface of the FRP net on the concrete structure side, is 1/3 or less of the mesh (mesh) of the FRP net, and has a square mesh of 1 to 30 mm. (Mesh)
(Iii) The fixture has an anchor through hole in the center;
A fitting portion capable of being fitted into at least one mesh (mesh) of the FRP net;
An outer edge wall provided facing the side wall of the fitting portion;
A holding groove provided between the side wall and the outer edge wall portion for holding the mesh thread of the two children;
(Iv) Insert the anchor into the mesh of a predetermined part of the FRP net, while placing (fixing) an anchor in the anchor through hole,
A method for preventing concrete peeling.   The fixing of the FRP net at the end of the FRP net is fixed at a predetermined interval by the fixing tool and the anchor at the outermost end of the mesh having an extra length of 10 mm to 1/2 of the mesh at the end. Item 2. The concrete peeling prevention method according to Item 1.