JP2010144376A - Net for preventing flaking of concrete, and method for preventing flaking of the concrete by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a net for preventing the flaking of concrete which can solve problems of lightweight properties, workability, construction performance in a step and a sump water section, a cost, etc. <P>SOLUTION: The net for preventing the flaking of the concrete includes: an FRP net body which is obtained by hardening a composite linear material in an unhardened state after netting it, and is formed of an unknotted net formed in a square-hole pattern and having a mesh size of 30-150 mm; and a biaxial mesh-like material in which a plurality of sheath-core composite fibers comprising a core component (a) formed of a polyolefin resin and a sheath component (b) formed of a polyolefin resin with a melting point lower by 20°C or higher than that of the core component are bundled to each other in which sea-island composite yarn obtained by fusing the sheath components together is netted, and which has a mesh size of 1-30 mm. The biaxial mesh-like material is fixed to the concrete structure-side surface of the FRP net body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a net for preventing concrete pieces from peeling off from concrete structures such as concrete tunnels, elevated carriageways, bridges, buildings, and the like, and a concrete peeling prevention method for concrete structures using the same. .

  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 have been studied, such as a method for preventing the deteriorated concrete from peeling off, various methods for repairing the peeled portion, and materials thereof. Among them, in a sheet for repair or reinforcement in which a protective layer serving as a surface layer and an adhesive layer to a concrete structure are provided in advance and a reinforcing layer composed of a fiber base material is interposed between these layers, the fiber A material using a sheet-like material obtained by processing organic fibers, inorganic fibers, or the like as a non-woven fabric or a woven fabric as a base material has been proposed as being able to facilitate the construction and stabilize the quality. (See Patent Document 1)
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 mesh is sandwiched between metal frame bodies (see Patent Document 2).
Furthermore, a construction method (see Patent Document 3) 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 through a support fitting.

  Furthermore, in view of the above problems, a method of attaching an FRP lattice bar which is lightweight, has the same reinforcement and hardening as a reinforcing bar and has little corrosion, to a concrete structure with an anchor bolt, an adhesive resin or the like has been proposed, and an improved mounting method thereof has been proposed. It has been proposed (Patent Document 4).

  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 having an arbitrary scale is prepared using an intermediate (uncured product) of a long fiber-reinforced synthetic resin linear material, the outer periphery of which is coated with a solidified thermoplastic resin, The thing which heat-hardened this mesh body is proposed (refer patent document 5). According to this mesh body, the drawbacks of conventional metal wires can be overcome.

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, and impregnation and adhesion of reinforcing fiber sheets, which increase construction costs. Moreover, since resin (adhesive) is used, it cannot be applied particularly when there is spring water at the repair site or when there is a large step such as a tunnel joint. In addition, since the concrete surface is covered and pasted, it is difficult to check the cracking condition after construction. Also, after repairing, moisture such as concrete gaps does not escape to the outside, and there is also a problem in terms of durability of the concrete. There is.

Moreover, the peeling prevention net described in Patent Document 2 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 tensioning method disclosed in Patent Document 3 is intended to prevent concrete fragments from being peeled off the lower surface of the road viaduct, and cannot be applied to the upper surface of a tunnel or a wall surface.
Further, in the FRP lattices described in Patent Document 4, the reinforcing bars are arranged in a lattice shape with a spacing of 30 to 150 mm from each other, the width is 3 to 10 mm, the thickness is 1 to 5 mm, and the surface has rigidity. Since it is relatively rigid, it is not suitable for being stretched over a stepped portion such as a tunnel joint. In addition, the weight is relatively heavy and expensive, and a problem remains in workability.

  On the other hand, in the mesh body described in Patent Document 5, since the intermediate body of the fiber reinforced synthetic resin linear material is in an uncured state, dripping or the like occurs during heat processing or the like, and the thermosetting resin after thermosetting There is a problem that the physical properties of the intermediate (uncured product) are not stable because the physical properties of the intermediate (uncured material) cannot be maintained over a long period of time because the physical properties of the intermediate cannot be controlled. there were.

As described above, the conventional net for preventing the concrete structure from peeling off has problems in lightness, workability, workability in a stepped part and a spring part, and price.
In addition, there is a problem with the dripping and storage stability of uncured linear materials even when trying to apply the FRP net body used for straw mats etc. due to its light weight, corrosion resistance, handling and work advantages. There were problems such as fluctuations in tensile properties.

  Therefore, in the present invention, as a result of intensive studies aimed at providing a net for preventing concrete peeling that can solve the above-described problems, the uncured composite linear material is cured after knitting (also referred to as a mesh). ) Preventing concrete from peeling off by fixing a FRP net body made of 30-150 mm square knotless net and a biaxial mesh with a mesh size of 1-30 mm formed by weaving a sea-island type composite yarn. It has been found that the above problems can be solved by using a network.

That is, the present invention
(1) A concrete peeling prevention net for preventing peeling of a concrete structure, the net covering (i) the outer periphery of a long fiber impregnated with an uncured thermosetting resin with a thermoplastic resin An FRP net body made of an unknotted net having a mesh size of 30 to 150 mm, and a core component made of (ii) (a) a polyolefin-based resin. And (b) a sea-island type composite in which a plurality of sheath-core type composite fibers composed of a sheath component made of a polyolefin resin having a melting point lower by 20 ° C. than the melting point of the core component are converged and the sheath components are fused together A biaxial mesh material having a mesh of 1 to 30 mm formed by woven mesh of yarn, and (iii) the biaxial mesh material is fixed to a surface of the FRP net body on the concrete structure side. , Characterized by Nkurito flaking prevention nets,
(2) An uncured composite linear material in which the thermoplastic resin covering the outer periphery of the long fiber is a polyolefin resin is used as a child yarn, the child yarns of the two mesh yarns are crossed with each other, and the mesh yarn is connected to the connecting portion. The FRP net body formed by passing through and linearly extending through the wire (ordinary type) and kneaded into a knotless net and the biaxial mesh-like material are in contact with at least the connecting portion of the FRP net body The net for preventing concrete peeling as described in (1) above, which is heat-sealed at the part,
(3) Resin whose polymerization unit is at least one selected from an acrylic ester compound, a methacrylic ester compound, and a vinyl compound in addition to the uncured thermosetting resin of the uncured composite linear material. And a penetrating thickener (B) made of a resin having a polymerization unit selected from at least one of an acrylic ester compound, a methacrylic ester compound, and a vinyl compound. And the blending amount of the thickener (A) is 0 with respect to 100 parts by mass of the total amount of the uncured thermosetting resin and 5 to 50 parts by mass of the penetration thickener (B). The concrete peeling prevention net according to (1) or (2), which is 5 to 50 parts by mass,
(4) The net for preventing concrete exfoliation according to any one of (1) to (3), wherein the intersection of the warp and weft of the biaxial mesh-like material is heat-sealed.
(5) The concrete peeling prevention net according to any one of (1) to (4), wherein a breaking load (tensile strength) of the cured composite linear body constituting the FRP net body is 400 N or more, and (6) Concrete peeling prevention method characterized by fixing the concrete peeling prevention net according to any one of (1) to (5) to a concrete structure,
Is to provide.

The net for preventing concrete exfoliation of the present invention is an FRP net body composed of a knotless network obtained by curing an uncured composite linear object after knitting, and a biaxial mesh object with a predetermined mesh is fixed to the FRP body. Therefore, it has flexibility and sufficient tensile strength as a concrete peeling prevention net, so that it can be used in a portion having a step such as a joint of a tunnel. In addition, even if it is used in a part with spring water, it is water permeable because it is a biaxial mesh-like material with a predetermined scale, and the composite linear material having FRP as a core component has a thermoplastic resin coating, The biaxial mesh is a polyolefin-based sea-island type composite thread, so there is no hydrolysis or reduction in strength due to water, and if the texture of the biaxial mesh is selected appropriately, it can capture fine concrete exfoliation pieces. It can be used effectively as a concrete peeling prevention net.
In addition, compared to the case where a large number of thin FRPs are stacked to produce FRP lattices, uncured uncured composite linear materials can be networked using a normal knitting machine, reducing costs. Can be achieved. In addition, the biaxial mesh material used in the present invention is a lightweight, if high-strength, specially-structured polyolefin-based sea-island composite yarns are constructed in a biaxial mesh shape, and the intersections of the biaxials are kept close by thermal fusion. Thus, a high-strength biaxial mesh-like product can be constructed, and if this biaxial mesh-like product is heat-sealed to the FRP net body, the function of preventing the fallen concrete pieces can be effectively expressed.
Moreover, if a specific thickener and a penetration thickener are blended with the uncured thermosetting resin of the uncured composite linear material, liquid dripping of the uncured composite linear material can be prevented. Therefore, it is possible to manufacture an FRP net main body having stable physical properties that do not change in physical properties.
According to the concrete stripping prevention method of the present invention, the concrete stripping prevention net of the present invention can be fixed to a concrete structure by an appropriate fixing means. An effective concrete peeling prevention method can be provided.

  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 net for preventing concrete peeling according to the present invention is obtained by curing an uncured composite linear object obtained by coating an outer periphery of a long fiber impregnated with an uncured thermosetting resin with a thermoplastic resin after a knitted net. Biaxially formed by weaving sea-island type composite yarns that converge a plurality of sheath-core type composite fibers made of a polyolefin resin and a sheath core-type composite fiber made of square-shaped, knotless network The biaxial mesh material is fixed to a surface of the FRP net body on the concrete structure side.
Moreover, it is more preferable in terms of preventing dripping if a predetermined amount of a predetermined thickener and a penetrating thickener is further contained in the uncured thermosetting resin of the uncured composite linear material.
FIG. 1 is a view showing an outline of a concrete peeling prevention net according to the present invention. A concrete peeling prevention net 1 is composed of an FRP net body 2 and a biaxial mesh-like object 3. Hereinafter, each component will be described in detail.

[FRP net body]
FIG. 2 is a schematic cross-sectional view of a cured composite linear object (hereinafter simply referred to as “composite linear object”) constituting the FRP net body 2 according to the present invention. Reference numeral 20 in FIG. 2 indicates a composite linear object made of a fiber-reinforced synthetic resin. The composite linear material 20 includes a long fiber 21, an uncured thermosetting resin 22 ′ that may include a thickener and a penetrating thickening ratio blended as necessary, and a solidified thermoplastic resin. And an uncured composite linear product 20 ′ composed of The long fibers 21 are impregnated with an uncured thermosetting resin 22 ′ and the outer periphery thereof is covered with a thermoplastic resin 23.
The FRP net body 2 includes, for example, a step of adding a thickener and a penetration thickener to the uncured thermosetting resin 22 ′, and a step of impregnating the uncured thermosetting resin 22 ′ with the long fibers 21. And an outer periphery of the impregnated long fiber 21 is coated with a thermoplastic resin 23 to form an uncured composite wire 20 ′, which is wound around a bobbin or the like, and the wound uncured composite wire And a step of knitting a knotless net using the shaped object 20 ′ and thermosetting the uncured thermosetting resin of the uncured composite linear object 20 ′. By doing so, the FRP net body 2 having a predetermined shape and physical properties can be obtained.
The outer diameter of the composite linear object 20 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 body 2 is also inflexible and increases in weight. The problem of workability arises.
Further, the breaking load (tensile strength) of the composite linear object 20 constituting the FRP net body 2 is preferably 400 N or more in terms of performance as a concrete peeling prevention net, more preferably 500 N or more, It is especially preferable that it is 600 N or more.

  When the above process is carried out without containing a thickener or a penetrating thickener, when the uncured composite linear 20 ′ is heat-treated, the liquid uncured thermosetting resin 22 ′ oozes out. Therefore, the uncured thermosetting resin 22 ′ can be appropriately thickened by containing a thickener or a penetrating thickener, and dripping from the end can be prevented.

  The acrylic ester compound used for the thickener refers to a compound having an acrylic ester structure and a derivative thereof, such as methyl acrylate, ethyl acetate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl. Examples include acrylate, sec-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl methacrylate and the like.

  The methacrylic acid ester compound used for the thickener means a compound having a methacrylic acid ester structure and a derivative thereof, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, n-hexyl. Examples include methacrylate and cyclohexyl methacrylate.

  The vinyl compound used for the thickener refers to a compound having a polymerizable vinyl structure, such as styrene, α-methylstyrene, divinylbenzene, and various functional groups such as alkyl groups and halogen atoms on these aromatic rings. Examples include substituted compounds.

  Further, the thickener may be a polymer composed of one type or a plurality of types of polymerization units of a methacrylic acid ester compound, an acrylate ester compound, and a vinyl compound, and a plurality of types of resins having different structures are mixed. Resin may be used. Furthermore, (1) a polymer comprising at least one of an acrylate ester compound, a methacrylic ester compound or a diene compound, and (2) a radical polymerizable unsaturated compound with an acrylate ester compound or a methacrylic ester compound. (3) A composite resin that is ion-crosslinked by adding metal ions to a polymer composed of a carboxylic acid.

  The thickener can be used as a powder resin. The particle size and the like of the resin powder used as the thickener is not particularly limited, but preferably 0.5 μm to 2.0 μm.

  In the composite linear object 20 according to the FRP net main body of the present invention, when the uncured composite linear object 20 ′ is heat-treated, the uncured thermosetting resin 22 ′ has a high viscosity and a gel. It is desirable not to make it. Since the uncured curable resin 22 ′ is gelled, the physical properties are likely to change as time passes.

  The type of penetrating thickener is not particularly limited, but benzyl methacrylate is preferably used. As the uncured thermosetting resin 22 ′, a thermosetting resin such as unsaturated polyester is used. In order to enhance the penetration effect of the thickener into the thermosetting resin, a penetration thickener is blended. In particular, benzyl methacrylate is suitable because it has a high penetrating effect on a thermosetting resin such as unsaturated polyester.

By adding the penetrating thickener, the thickener can be well penetrated into the uncured thermosetting resin 22 'and mixed uniformly. That is, excessive thickening due to poor dispersion of the thickening agent can be suppressed, a desired thickening speed can be achieved, and a dripping phenomenon can be prevented.
Thus, by using not only the thickener but also the penetration thickener, the dripping phenomenon does not occur, and the uncured composite linear product 20 ′ suitable for practical use can be obtained.

  The blending amount of the thickener and the penetration thickener is not particularly limited, but preferably the following blending amount is desirable. It is desirable that 0.5 to 50 parts by mass of the thickener is contained with respect to 100 parts by mass of the total amount of the uncured thermosetting resin and 5 to 50 parts by mass of the penetration thickener. Thereby, the suppression effect of the amount of dripping can be improved more.

  If the amount of penetrating thickener added is too large, the resin thickening rate will be too fast, for example, the binder component contained in the long fibers will elute into the impregnated resin due to the influence of the penetrating thickener, The thickening may be promoted excessively. In this case, within the scope of the present invention, the rate of thickening can be adjusted by reducing the amount of penetrating thickener added or by reducing the amount of thickener added.

  The type of the long fibers 21 as the reinforcing fibers used in the present invention is not particularly limited, and synthetic fibers such as polyolefin fibers and polyester fibers, inorganic fibers such as glass fibers, metal fibers, 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 21 is not particularly limited, and can be appropriately selected in consideration of the purpose of use and ease of processing. Further, the volume content of the fiber 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 22 ′ used in the present invention is not particularly limited as long as it can be cured by heating, and is preferably unsaturated with excellent performance stability after curing. A polyester resin, an unsaturated alkyd resin, an epoxy resin, or the like is desirable, more preferably a crosslinkable substance is contained, and more preferably, at least one of an unsaturated polyester resin, an unsaturated alkyd resin, and an epoxy acrylate. It is desirable to contain 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 type of the thermoplastic resin 23 used in the present invention is not particularly limited, but is preferably a substance having excellent flexibility, and a polyolefin resin or the like can be preferably used. In addition, when the uncured thermosetting resin 22 ′ contains a crosslinkable substance, it is desirable that the uncured thermosetting resin 22 ′ has a property of being hardly eroded by the crosslinkable substance. More preferably, the durability can be improved by using a material that does not easily wear. In the present invention, the combination of the long fibers 21, the uncured thermoplastic resin 22 ′, and the thermoplastic resin 23 is not particularly limited.

FIG. 3 shows an FRP net body 2 using the composite linear object. The FRP net body 2 shown in the figure is a knotless network without a knot at the connecting portion 24. If the net yarn composed of the uncured composite linear material 20 ′ is a double-filament yarn and a knotless net is knitted, the mesh is accurate, the connecting portion 24 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 can be mentioned, but in particular, since it is lightweight and has a uniform mesh, it is preferable to use a penetration type (normal type) no knot net.

  At the stage where a knotless net is produced by a knitting network machine, the mesh can be opened in a diamond shape or a square shape, but the FRP net body 2 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, and the uncured thermosetting resin is cured and the square net-shaped heat is set (fixed).

Regarding the mesh of the FRP net body 2 used in the present invention, in the present invention, the center-to-center distance W between opposing mesh yarns constituting the mesh is defined as the mesh. The mesh W (25) of the FRP net body needs to be 30 to 150 mm in size, and the mesh is in this range, the strength of the composite linear material, the biaxial mesh material 3 used in combination However, when the composite linear object 20 having an outer diameter of 2.1 mm is used, the 50 mm square is particularly preferable from the balance with the flexibility of the FRP net body 2.
In addition, the width of the FRP net body is determined by the relationship with the knitting network machine, and the maximum length of the FRP net body is about 18 m. Corresponding to the construction method of the prevention part, etc., it can supply as appropriate width and length.

[Biaxial mesh]
The biaxial mesh-like object 3 constituting the concrete peeling prevention net of the present invention has a core component 31 made of (a) a polyolefin-based resin and (b) the melting point of the core component 32 shown in FIG. What is formed by weaving a sea-island composite yarn 30 shown in FIG. 4 (B) in which the sheath component of a sheath-core composite fiber 33 made of a polyolefin resin having a melting point lower than 20 ° C. is fused. It is. In the present invention, the scale of the biaxial mesh is defined as a distance Y (mm) between the center portions of adjacent warps or adjacent wefts, as shown in FIG. The mesh of the biaxial mesh-like product according to such definition is preferably 1 to 30 mm, more preferably 1 to 20 mm, and particularly preferably 2 to 10 mm. If the mesh size is less than 1 mm, clogging may occur with the peeled small pieces, resulting in poor water permeability, and if it exceeds 30 mm, the peeled pieces cannot be captured effectively.
The biaxial mesh-like material used in the present invention has a flat sea-island type composite yarn, so that it is naturally twisted in the process of winding it on a bobbin or the like, or in the weaving process, and is a partially twisted part Is inevitable, but is a plain weave biaxial mesh made of almost 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.

(Polyolefin resin)
Examples of the polyolefin-based resin that can be used for the biaxial mesh-like product 3 of the present invention include binary copolymers of olefins such as polyethylene, polypropylene, ethylene, propylene, and butene-1, or ternary copolymers. It is done.

The biaxial mesh-like product 3 of the present invention has a mesh having a mesh of 1 to 30 mm, that is, a so-called square opening, obtained by weaving the sea-island type composite yarn 30 with a plain weave or the like as shown in FIG. . 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.
The sea-island type composite yarn 30 is a sheath core composed of (a) a core component 31 made of a polyolefin resin and (b) a sheath component 32 made of a polyolefin resin having a melting point 20 ° C. lower than the melting point of the core component 31. A large number of type composite fibers 33 are bundled and the sheath components 32 are fused together. A suitable combination of the core component and the sheath component is, for example, isotactic polypropylene (mp = 163 ° C.) as the core component. ), A combination using linear low density polyethylene (mp = 110 ° C.) as the sheath component.
The sea-island type composite yarn 30 is spun to have a predetermined sheath / core cross-section ratio using a conventional composite spinning equipment and a core-sheath type composite spinning nozzle by, for example, a spin draw method, and led to a drawing apparatus that is directly connected. Then, it can be obtained by stretching under saturated water vapor pressure and fusing between fibers with a sheath component together with stretching. Moreover, it can manufacture by the method as described in Unexamined-Japanese-Patent No. 2003-326609.
The thermal fusion of the intersection 34 of the sea-island type composite yarn can be achieved by a method such as pressing a roller heated above the melting point of the sea (sheath) component 32 of the biaxial mesh.

[Fixing of biaxial mesh and FRP net body]
In the concrete peeling prevention net 1 of the present invention, as shown in an enlarged view of one scale in FIG. 6, the biaxial mesh 3 and the FRP net body 2 are connected to the two connecting portions 24 of the FRP net body 2. It is necessary to be fixed on the contact side with the shaft mesh. The purpose of fixing is to first integrate the FRP net body 2 and the biaxial mesh-like object 3 to improve handling at the time of manufacturing, storage and construction, and at the same time, the opening 25 of the FRP net body 2. In the unlikely event that concrete is peeled off from the biaxial mesh-like object 3 that covers the load, the load from the concrete peel-off piece is passed through the composite linear object 20 near the load part constituting the FRP net body 2. This is because the load is applied to the FRP net body 2 and the load can be shared with the concrete structure through a member for fixing the FRP net body 2. This is to prevent the FRP net body 2 from bulging out from the mesh (opening) 25 as much as possible.
Specific examples of fixing means include a method using an adhesive and a method using heat fusion.

(Heat fusion between biaxial mesh and FRP net body)
As the means for fixing, heat fusion is simple. Since the composite linear object 20 constituting the FRP net body 2 has a thermoplastic resin coating 23, the thermoplastic resin coating 23 is used as the sea island type composite yarn 30 constituting the biaxial mesh-like object 3. A material that can be heat-sealed with the polyolefin resin of component 34 is selected, and the FRP net body 2 and the biaxial mesh-like material 3 are overlapped and passed through a heat roller heated to a temperature near the melting point. Can be worn.
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 concrete peeling prevention net of the present invention may be subjected to various treatments as needed after the production stage of the FRP net body, the production stage of the biaxial mesh, or a combination thereof.
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.

The present invention also provides a concrete peeling prevention method using the above-mentioned concrete peeling prevention net.
The concrete peeling prevention method of the present invention is fixed to a concrete structure in a state where the continuous contact of the FRP net body 2 of the concrete peeling prevention net 1 and the composite linear object 20 are held by a washer or a dedicated jig. There is a method of fixing to the concrete structure side with anchor bolts or the like. Further, it may be fixed with a relatively long metal fixing frame or the like. Alternatively, a hook-shaped fixture may be laid in advance on the concrete structure, and the construction may be performed so that the composite linear object of the FRP net body is hung on the fixture. Since the FRP net body is deformed to some extent, it can follow the deformation for hanging.
In addition, in order to fix to the fixing bracket, etc., the biaxial mesh-like material at the part is an obstacle to work, but the intersection of the warp and weft of the biaxial mesh-like material is heat-sealed and sealed. If this is the case, it can be constructed without the biaxial mesh-like thread coming off or falling off, coupled with fixing to the FRP net body.

Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these examples.
In addition, the dripping and physical properties of the uncured composite linear material of the production example were measured by the following methods.

(1. Evaluation method of liquid sag test)
The sample length was 50 cm, and two samples were bundled. Two samples were twisted 30 times, the impregnated resin squeezed thereby was collected in a measuring bottle, and the amount collected was weighed.
In that case, it verified about each under 20 degreeC atmosphere (low-temperature conditions) and 30 degreeC atmosphere (high-temperature conditions) as conditions which store the fiber-reinforced synthetic fiber linear thing.

  The evaluation was performed according to the following procedure. Two samples (sample diameter 2.1-2.18 mm) are fixed in parallel with an iron jig. At that time, the sample was fixed with an iron jig with the upper part of 1.0 cm and the lower part of 4.0 cm protruding, and was fixed with a clearance of 1.8 mm as a clearance interval.

  Subsequently, the two fixed sample bundles were rotated 30 times and fixed to the arm. When fixing the arm, care was taken not to apply too much tension, and it was confirmed that the twisted sample bundle extended vertically. The sample bundle was twisted 30 times, and the impregnated resin squeezed thereby was collected in a measuring bottle, and the amount collected was measured as the amount of dripping. The measurement was performed every predetermined number of elapsed days after the start of the sample test. Unless otherwise specified, the amount of dripping is the amount of dripping per 20 minutes (mg / 20 min).

(2. Physical property measurement)
The produced uncured composite linear material was stored for 28 days in a 20 ° C. atmosphere (low temperature condition) and a 30 ° C. atmosphere (high temperature condition), respectively, and the amount of liquid dripping was measured.
And after the amount of dripping stopped, it was immersed for 15 minutes and hardened in a 98 degreeC hot water bath. Thereafter, the tensile strength and bending strength were measured, and the physical properties obtained were compared with those obtained by curing immediately after the preparation of the uncured composite linear material, to determine the retention rate. The tensile speed is 200 mm / min, the fulcrum distance is 150 mm, the bending speed is 5 mm / min, and the fulcrum distance is 30 mm.

(Manufacture of uncured composite linear material)
Production Example 1
A polyester long fiber of 14300 total dtex (trade name “E1100T190-H02” manufactured by Toyobo Co., Ltd.) made of 13 untwisted yarns of 1100 dtex / 13 is added to polymethyl methacrylate resin powder (Nippon Zeon ( Unsaturated polyester resin (product name: “Yupika 9001”, manufactured by Nippon Yupica Co., Ltd.) containing a product name “ZEBUIAC F320”, a particle diameter of 1 μm) and benzyl methacrylate as a penetrating thickener is not yet available. An uncured product impregnated as a cured thermosetting resin and drawn to an outer diameter of 1.05 mm, and then the uncured product is led to the head of a melt extruder, and the outer periphery thereof is made of a polyethylene-based thermoplastic. Covered in a ring with a resin (made by Nippon Unicar Co., Ltd., trade name “NUCG5350”), led to a water cooling tank, cooled and solidified the thermoplastic resin coating layer, The cured shaped composite linear material wound on a bobbin. In addition, the uncured thermosetting resin of the uncured composite linear material is composed of 1 part by weight of polymethyl methacrylate as a thickener and benzyl methacrylate as a penetrating thickener with respect to 75 parts by weight of the unsaturated polyester resin. 25 parts by mass is blended. The resulting uncured composite linear product had a diameter of 2.11 mm.

  The amount of dripping of the thermosetting resin of the uncured composite linear product obtained in Production Example 1 was 84 mg immediately after production, whereas it was 0 mg after 14 days at low temperature and after 2 days at high temperature. It was not dripping. Moreover, the tensile strength of the sample which hardened | cured what was stored at the low temperature of the unhardened composite linear thing is 1091N (retention rate 100%), bending strength is 9.4N (retention rate 100%), The tensile strength of a sample obtained by curing the material stored at 1,089 N (retention rate 99.9%) was 9.1 N (retention rate 98.9%). That is, it was shown that the tensile strength and bending strength hardly decreased after the amount of dripping was stopped.

Reference production example 1
An uncured composite linear product was obtained under the same conditions as in Production Example 1 except that the thickener was not included. As for the amount of dripping, even after 28 days, a dripping amount of 45 mg at low temperature and 10 mg at high temperature was observed. In addition, after the sag amount stopped, the bending strength retention rate was 97.9% at low temperature and 92.6% at high temperature, which was lower than that of Production Example 1.

[Manufacture of FRP net body]
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 body.
The obtained FRP net body had a unit weight of 640 g / m ² and an apparent thickness of 4.8 mm.
When the sample of the composite linear object constituting the FRP net main body was loosened from the net main body, the outer diameter was 2.11 mm, the unit weight was 4 g / m, and the breaking load was 1080 N.

[Manufacture 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%.

[Manufacture 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.

Example 1
The upper surface of the FRP net body obtained as described above and the lower surface of the biaxial mesh-like object are each contact-heated with a heating roller having a surface temperature of 150 ° C., and the surface of the composite linear object covering portion resin of the FRP net body The surface part of the sea part resin of the sea-island type composite yarn of biaxial mesh-like material is melted, and these are superposed and passed through a pressure roller, and the FRP net body and the biaxial mesh-like substance are heat-sealed. Thus, a concrete peeling prevention net was obtained.
The heat fusion was performed at the connecting portion (intersection portion of the net yarn) of the FRP net body.

[Measurement of physical properties of net for preventing concrete peeling]
About the obtained concrete peeling prevention net | network, the rigidity and the adhesive force of a mesh-like thing and a FRP net main body were measured with the following method, and the result was obtained.

(1. Measurement of bending resistance of concrete peeling prevention net)
As shown in FIG. 7 (A), a sample of 24 cm × 5.5 cm is prepared so that the 4 th mesh is included, and in accordance with the cantilever method of JIS L 1096 in the state of (A) front surface and (B) back surface, Was measured by the amount of deflection.
Specifically, as shown in FIG. 8, when the sample 45 is pressed by the fixture 44 so that the sample S protrudes 15 cm from the end 43 of the table 42 having the 45 ° inclined portion, and a load 45 is applied to the tip of the sample. The amount of deflection X (mm) was measured with a metal rule 46. The measurement results are shown in Table 1.

When the mesh-like object was measured as the upper surface, a result with less deflection was obtained. This is presumably because the tensile stress acting surface with respect to the bending load becomes the surface of the mesh-like material, and the reinforcing effect on the FRP net body 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.

(2. Adhesive strength between mesh and FRP net body)
i) Adhesive peel strength Adhesive peel strength between the composite linear material of the FRP net body and the sea-island composite yarn of the mesh-like material was measured as follows. A sample is cut out from the concrete peeling prevention net 1 of the present invention so as to include one connecting portion of the net as shown by the dotted line range in FIG. 9, and is schematically shown in FIG. 10 (a). Cut the yarn that crosses it so that there is only one mesh yarn (composite linear material) made of composite linear material and only one sea-island type composite yarn that is heat-sealed on the surface of the connecting part. Then, a test sample as shown in FIG. 10 (b) is prepared, and as shown in FIG. 10 (c), a chuck 41 of a universal type tensile tester (Orientec Corp .: TENSILON universal tester RTA-100) is prepared. Then, the tensile strength was applied at a speed of 200 mm / min, and the peel strength was measured. The peel strength was 1.5 N on average for 4 samples.
ii) Shear bond strength The shear bond strength between the composite linear product of the FRP net body and the sea-island composite yarn of the mesh product was measured as follows. From the concrete peeling prevention net 1 of the present invention, a sample is cut out so as to include the four connecting portions of the net as shown by the dotted line range in FIG. 9, and FIG. 11 (a) front view and FIG. 11 (b) side view. As shown in FIG. 4, the upper chuck 41 grips only the mesh-like object 3 and the lower chuck grips only the FRP net body 2 in a state including the four contact points, and pulls at the same speed as described above. And the shear bond strength was measured. The average value of 4 samples was 23.7N.

(3. Load test of concrete peeling prevention net)
With respect to the concrete peeling prevention net 1 obtained in Example 1, the strength of the net was measured with reference to the following “Peeling prevention punching test method”.
That is, with reference to the Japan Highway Public Corporation Standard, JHS424: 2004, “Peeling Prevention Push-out Test Method”, a concrete structure is provided on a concrete peeling prevention net (simply called “net”) installed on the surface of a concrete structure. The load resistance of the net and the amount of displacement of the net when the load from the peeled piece was applied from the object side were measured to evaluate the performance of the net.
An upper lid type U-shaped side groove (lid) nominal name 300 (400 × 600 × 60 mm) (hereinafter referred to as “U-shaped lid”) defined in JIS A5372 was used.
The central part of the U-shaped lid 50 was cored (perforated) with a concrete core cutter in a shape of φ100 mm. The core removal direction was penetrated from the back surface (opposite surface on the biaxial mesh-like object 3 side) to form the core 51.
Next, prepare a net sample with a size of 40 cm x 30 cm, place it on the U-shaped lid so that 2 mm of the net body faces the center side of the core of Φ100 mm, and on both ends of the net sample on the 40 cm side, An iron plate (presser) 52 having a width of 5 × 60 mm × 300 mm is placed, and three shingles vise 53 (maximum opening: 150 mm) are set on the iron plate and the lower surface of the U lid, and the net 1 is placed in the U Fixed to the lid surface.
Next, as shown in FIG. 12, it is set upside down on a gantry (not shown) of the measuring apparatus, and the perforated core 51 is penetrated by a loader 54 having a tip of Φ100 mm so that a load is applied to the net sample. Was loaded.
Loading was performed at a speed of 2 mm / min, a punching load was applied, and the maximum punching load (maximum load bearing capacity) and displacement were recorded on a chart.
The measurement of n = 1 was performed, the average of the maximum load resistance was 3813 N, and the displacement at that time was 53 mm.

The net for preventing concrete exfoliation of the present invention is an FRP net body composed of a knotless network obtained by curing an uncured composite linear object after knitting, and a biaxial mesh object with a predetermined mesh is fixed to the FRP body. Thus, the concrete peeling prevention net has flexibility and sufficient tensile strength, and can be used as a peeling prevention net in a portion having a step such as a tunnel joint. Since a biaxial mesh-like material having a predetermined mesh is used in combination, it has water permeability and can be used as a net for preventing peeling of a portion with spring water.
The FRP linear material has a thermoplastic resin coating, and the biaxial mesh material is a polyolefin-based sea-island composite yarn, so there is no hydrolysis or decrease in strength due to water, and the mesh of the biaxial mesh material can be selected as appropriate. For example, it can be effectively used as a low-cost concrete peeling prevention net that can capture fine concrete peeling pieces.
According to the concrete stripping prevention method of the present invention, the concrete stripping prevention net of the present invention can be fixed to a concrete structure by an appropriate fixing means. It can be used as an effective method for preventing concrete peeling.

It is explanatory drawing of the net for concrete peeling prevention of this invention. (A) It is a composite linear object which comprises the FRP net main body which comprises this invention. (A) It is explanatory drawing of the FRP net main body which comprises this invention. It is explanatory drawing of (A) sheath core type composite fiber and (B) sea-island type composite yarn which comprise the biaxial mesh-like thing of this invention. It is explanatory drawing of the biaxial mesh-like thing which comprises this invention. It is an expansion explanatory view for 1 square of the net for concrete peeling prevention of the present invention. It is a photograph which shows the (A) surface and the (B) back surface of the sample for a bending resistance measurement. It is explanatory drawing of a bending resistance measuring apparatus and a measuring method. It is a figure which shows the collection | recovery site | part of the sample for the adhesive force measurement of a mesh-like thing and a FRP net main body. It is explanatory drawing of the measurement procedure of adhesive peeling strength. It is explanatory drawing of the measuring method of shear bond strength. It is explanatory drawing of a load bearing test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Net for preventing concrete peeling 2 FRP net body 3 Biaxial mesh-like material 4 Fastening point 20 Composite linear material 20 'Uncured composite linear material 20 "Net yarn (two strands of composite linear material)
21 Long fiber 22 Cured thermosetting resin 22 'Uncured thermosetting resin 23 Thermoplastic resin 24 Joint 25 Contour (Cut, Opening)
30 Sea-island type composite yarn 31 Core component 32 Sheath component 33 Sheath-core type composite fiber 34 Intersection 35 Mesh of biaxial mesh (opening)
41 Measuring chuck 42 Measuring table 43 Measuring table end 44 Fixing tool 45 Load 46 Metal scale W FRP net body mesh Y Biaxial mesh texture 50 U lid 51 Perforated core 52 Iron plate (presser)
53 giant clam vise 54 load

Claims (6)

A concrete peeling prevention net for preventing a concrete structure from peeling off,
(I) A square shape having a mesh size of 30 to 150 mm obtained by curing an uncured composite linear product obtained by coating the outer periphery of a long fiber impregnated with an uncured thermosetting resin with a thermoplastic resin after knitting. FRP net body consisting of no knot network,
(Ii) Converging a plurality of sheath-core type composite fibers comprising a core component made of (a) a polyolefin-based resin and (b) a sheath component made of a polyolefin-based resin having a melting point 20 ° C. lower than the melting point of the core component. And a biaxial mesh-like material having a mesh of 1 to 30 mm formed by weaving a sea-island type composite yarn obtained by fusing the sheath components together,
(Iii) The biaxial mesh-like material is fixed to the surface of the FRP net body that is on the concrete structure side.
A net for preventing concrete peeling.   The uncured composite linear material in which the thermoplastic resin covering the outer periphery of the long fiber is a polyolefin resin is used as a child thread, the child yarns of the two mesh threads are crossed with each other, and the mesh thread penetrates the connecting portion. The FRP net main body formed by knitting and curing in a straight (through-through) (ordinary type) braided net and the biaxial mesh-like material are heated at least at the contact portion with the connecting portion of the FRP net main body. The net for preventing concrete from peeling off according to claim 1, which is fused.   In addition to the uncured thermosetting resin of the uncured composite linear material, an increase comprising a resin having a polymerization unit of at least one selected from an acrylate compound, a methacrylate compound, and a vinyl compound. A thickener (A) and a penetration thickener (B) made of a resin having a polymerization unit selected from at least one of an acrylic ester compound, a methacrylic ester compound, and a vinyl compound, And the compounding quantity of the said thickener (A) is 0.5- with respect to 100 mass parts of total amounts of the said uncured thermosetting resin and 5-50 mass parts of the said penetration thickener (B). The net for preventing concrete peeling according to claim 1 or 2, wherein the net is 50 parts by mass.   The net for preventing concrete peeling according to any one of claims 1 to 3, wherein an intersection of warp and weft of the biaxial mesh-like material is heat-sealed.   The net for preventing concrete exfoliation according to any one of claims 1 to 4, wherein a breaking load (tensile strength) of the cured composite linear material constituting the FRP net main body is 400 N or more.   A concrete exfoliation preventing method, comprising fixing the concrete exfoliation prevention net according to any one of claims 1 to 5 to a concrete structure.

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