JP5722714B2 - Concrete peeling prevention sheet and concrete peeling prevention method using the same - Google Patents

Description

  The present invention relates to a protective sheet for preventing a concrete piece from peeling off from a concrete structure such as a railway, a bridge such as a road, a tunnel, an elevated road, or a building, and a concrete peeling prevention method using the same.

  In concrete structures, concrete peels off due to the ingress of rainwater from the outside and corrosion of internal reinforcing bars due to deterioration factors such as salinity and neutralization in the natural environment over time. May occur. As a measure for preventing concrete from peeling off due to deterioration of a concrete structure, a method of adhering mesh fibers made of vinylon fiber, polypropylene fiber, or the like with an adhesive such as an epoxy resin, a urethane resin, or a polyester resin has become widespread.

  In Patent Document 1, a specific resin composition is affixed to a primer-treated concrete surface impregnated with a curable material for preventing concrete peeling impregnated into one or more selected from biaxial mesh, triaxial mesh and fiber layered body, or After applying the resin composition to the primer-treated concrete surface, affixing one or more selected from biaxial mesh, triaxial mesh and fiber layered body and further applying the resin composition to the primer-treated concrete surface A method of forming and curing is disclosed. Patent Document 2 discloses a method in which a primer layer, a main material layer, a concrete peeling prevention sheet, a main material layer made of a water-based polyurethane paint, and a top coat layer are sequentially laminated on the concrete surface. Patent Document 3 proposes a construction method in which a fiber mesh is stuck with a polymer cement mortar after construction with an epoxy crack impregnating material. Patent Document 4 proposes a method in which a concrete structure is covered with a mesh fiber sheet, fixed with mortar, and covered with a covering material such as acrylic resin-based polymer cement mortar.

  However, the above-mentioned conventional method has a problem that it takes a long construction period and the construction cost is high.

JP 2004-18719 A JP 2007-247290 A JP 2008-57146 A JP 2011-32694 A

  In order to solve the above problems, the present invention provides a concrete stripping prevention sheet that can increase the reinforcing strength, shorten the construction period, and reduce the construction cost by using a novel protective sheet, and a concrete stripping prevention method using the same. I will provide a.

The concrete peeling prevention sheet of the present invention is a concrete peeling prevention sheet for covering a concrete surface, and a fiber yarn net and a nonwoven fabric are bonded and integrated, and each fiber yarn constituting the fiber yarn net is , A tape yarn in which multifilament yarns composed of high-strength polyethylene fibers are arranged in a flat shape, and the fiber yarn net is a biaxial array composed of warp yarns and weft yarns. It is characterized in that it has a structure in which a weft thread is sandwiched between them or a structure in which a weft thread is sandwiched between two vertical warp threads .

  The concrete exfoliation prevention method of the present invention is a method of covering and fixing a concrete exfoliation prevention sheet on the concrete surface, applying a primer / adhesive as a first layer to the concrete surface, and then applying the above-mentioned concrete as a second layer from above. The peeling prevention sheet is bonded so that the fiber yarn net becomes a concrete surface, and an adhesive is applied as a third layer from above.

  Since the concrete peeling prevention sheet of the present invention is in surface contact with the concrete surface, the adhesive strength is high, and when stress is applied from the concrete to the sheet, the nonwoven fabric suppresses the movement of the fiber yarn constituting the net, and synergistic reinforcement The effect is exhibited and the anti-peeling performance can be enhanced. In addition, since the fiber yarn net and the nonwoven fabric are bonded and integrated, the sheet of the present invention is a thin sheet as a whole, so that the amount of adhesive to be impregnated can be reduced when constructing on a concrete surface. For this reason, the frequency | count of application | coating of an adhesive agent and an application quantity can be decreased, a construction period can be shortened, and construction cost can be made cheap.

FIG. 1A is a schematic plan view of a concrete exfoliation preventing sheet according to an embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view taken along the line II of FIG. 1A. FIG. 2 is a schematic cross-sectional view of a fiber yarn net used for a concrete peeling prevention sheet in another embodiment of the present invention. FIG. 3 is an explanatory view showing a manufacturing process of a concrete exfoliation preventing sheet in one embodiment of the present invention. 4A-C show a construction method according to an embodiment of the present invention, FIG. 4A shows a step of applying a first layer primer / adhesive to the concrete surface, and FIG. 4B shows a step of bonding a second layer sheet, FIG. 4C shows the process of apply | coating the adhesive agent of a 3rd layer. FIGS. 5A to 5C are explanatory views showing a measuring method of a peeling prevention punch test used in the embodiment of the present invention. FIG. 6 is a chart showing the results of a concrete peeling prevention punching test of the protective sheet in Example 1 of the present invention. FIG. 7 is a chart showing the results of the concrete peeling prevention punching test of the protective sheet in Comparative Example 1. FIG. 8 is a chart showing the result of the concrete peeling prevention punching test of the protective sheet in Comparative Example 2. FIG. 9 is a chart showing the result of the concrete peeling prevention punching test of the protective sheet in Comparative Example 3. FIG. 10 is a chart comparing the results of the concrete peeling prevention punching test of the protective sheets of Example 1 and Comparative Example 1 of the present invention.

  In the present invention, a concrete peeling prevention sheet in which a fiber yarn net and a nonwoven fabric are bonded and integrated is used. The concrete peeling prevention sheet is also called a protective sheet. This protective sheet is composed of a fiber yarn net and a nonwoven fabric, and both are integrated. The integration is preferably at least one means selected from adhesive bonding, thermal fusion, and fiber entanglement. In the above, the entanglement includes entanglement by water flow or entanglement by needle punch. In the case of thermal fusion, low-melting fibers are added to the nonwoven fabric, and these are thermally fused, so that they can be integrated without lowering the strength of the fiber yarn net and / or the nonwoven fabric. Among the above-mentioned integration means, adhesion with an adhesive is preferable because the strength of the protective sheet is maintained high and the integration process is also efficient. The protective sheet in which the fiber yarn net and the nonwoven fabric are bonded and integrated is in surface contact with the concrete surface. In addition, this protective sheet is formed by laminating a fiber yarn net and a non-woven fabric, and can be a thin sheet as a whole.

  This will be described with reference to the drawings. In the following drawings, the same symbols indicate the same items. FIG. 1A is a schematic plan view of a concrete exfoliation preventing sheet according to an embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view taken along the line II. The protective sheet 10 is composed of a nonwoven fabric 1 and a fiber yarn net 4, and both are integrated. The fiber yarn net 4 is composed of warp yarns 2a, 2b and a weft yarn 3, and the warp yarns 3 are alternately sandwiched between the warp yarns 2a, 2b. As another example, as shown in FIG. 2, it may be a fiber yarn net 7 in which the weft yarn 6 is sandwiched between the upper and lower warp yarns 5a and 5b. These are biaxial arrays. Each fiber yarn constituting the net is preferably a tape yarn in which multifilaments are arranged in a flat shape. When the multifilament is a tape thread arranged in a flat shape, surface bonding to the concrete surface is possible, and the bonding strength is increased. In a preferred flat shape, the relationship between the width W and the thickness H is W: H = 2 to 20: 1.

  In the fiber yarn net, warp yarns and weft yarns are linearly arranged, and there is no crossing due to replacement of warp yarns and weft yarns as in woven fabrics, so that the strength inherent to the fiber is hardly impaired. In addition, since there is no weaving process like a woven fabric, there is an advantage that a product without fuzz and misalignment can be obtained.

  The material of the fiber yarn net is preferably polyethylene fiber, polypropylene fiber, vinylon fiber, aramid fiber, polyester fiber, polyamide (nylon) fiber, polyparaphenylene benzbisoxazole fiber (PBO), carbon fiber, glass fiber or the like. Vinylon fiber has been put to practical use as a concrete reinforcing fiber. Among them, high strength polyethylene fiber or high strength vinylon is preferable. In particular, high-strength polyethylene fibers have a formability (a property that remains bent along the uneven shape of concrete), an adhesive having a low viscosity of 10 mPa · s to 20,000 mPa · s and a thixotropy index of 7 or less. Is preferable because it can be used. For example, if the protective sheet layer 24 in FIG. 4B has a property of being bent along the uneven shape of the concrete 21, it is convenient to apply the adhesive from above.

  High-strength polyethylene fiber is made from linear high-density polyethylene with a molecular weight of 500,000 or more, and a semi-dilute solution is prepared and gel-spun to form a gel-like yarn with very little molecular entanglement. (Encyclopedia of Textiles, edited by Tatsuya Motomiya et al., March 25, 2002, Maruzen, pages 521-522). Currently, fibers having a strength of 24 to 60 cN / dtex and an elastic modulus of 880 to 2200 cN / dtex are commercially available. Commercially available products include Toyobo Co., Ltd., product name “dyneema”, Allied Signal, product name “Spectrama”, Mitsui Chemicals, Inc., and product name “Techmiron”.

The thread interval of the fiber thread net is preferably 0.5 to 3/10 mm for both warp and width. More preferably, it is 0.5-1.5 / 10mm. If it is the said range, intensity | strength is enough and the impregnation property (penetration) of an adhesive agent is also favorable. The preferred fineness of warp and weft yarns is in the range of 500 to 3000 deci tex. The weight per unit area (weight per unit area) of the fiber yarn net is preferably in the range of 10 to 400 g / m ² .

The nonwoven fabric preferably has a weight (unit weight) per unit area of 10 to 50 g / m ² . More preferably, it is 15-30 g / m < ² >. If it is the said range, intensity | strength and the impregnation property (penetration) of an adhesive agent can be made compatible. The non-woven fabric with the basis weight is thin enough to show through.

  The nonwoven fabric is preferably at least one nonwoven fabric selected from a spunbond nonwoven fabric, a thermal bond nonwoven fabric, a needle punched nonwoven fabric, a spunlace nonwoven fabric, and a melt blown nonwoven fabric because both strength and adhesive impregnation (penetration) can be achieved. Among these, a spunbonded nonwoven fabric is preferable because it is thin and strong. By mixing low-melting fibers in the spunbonded nonwoven fabric and fusing the low-melting fibers, it is possible to obtain a nonwoven fabric with good fiber cohesiveness and high strength even if it is thin.

The weight (unit weight) per unit area of the protective sheet of the present invention is preferably in the range of ^{20 to} 450 g / m ² . More preferably, it is the range of 30-400 g / m < ² >. If it is the said range, intensity | strength and the impregnation property (penetration) of an adhesive agent can be made compatible.

The manufacturing process of one Example of the protection sheet of this invention is shown in FIG. First, a laminated sheet 8 in which warp yarns and weft yarns are laminated is made, passed through a guide roll 9 and impregnated in a binder liquid 12 in an impregnation tank 11. Thereafter, the pair of mangles (squeezing rolls) 13 and 14 are squeezed so that the amount of the adhesive resin liquid becomes a predetermined amount, and sent to the drying cylinders 17 and 18. The nonwoven fabric 15 is supplied from the upstream side of the guide roll 16 between the mangles 13, 14 and the drying cylinders 17, 18, bonded to the laminated sheet 8, supplied to the drying cylinders 17, 18 and dried, and the obtained protective sheet 10 is a winding body 19. When this protective sheet is coated on the concrete surface, it is cut into an appropriate size and used. As the binder liquid 12, an acrylic resin, a urethane resin, a vinyl acetate resin, a polyvinyl alcohol resin, an olefin resin, or the like is preferable. The preferable dry weight of the adhesive (binder) in this case is 5 to 50 g / m ² .

Next, the construction method of the present invention will be described. The construction method of the present invention includes the following steps.
(1) 1st process As a 1st process, the primer and adhesive agent used as the 1st layer is applied to the concrete surface. Prior to this step, care may be taken in advance, such as cleaning the concrete surface, closing cracks, flattening, correcting steps and smoothing. As the primer / adhesive serving as the first layer, one component selected from the group consisting of an epoxy resin, a urethane resin, a silicone resin, a vinyl ester resin, a polyester resin, an acrylic resin, a polyolefin resin, and a polymer cement or a reaction curing type It is preferable to use a synthetic resin adhesive. Further, a thixotropic agent, a pigment, an antifoaming agent, a diluent and the like can be added to the adhesive. Among these, it is preferable to use an epoxy resin in consideration of physical properties such as workability and strength. The range of the preferable application amount of the primer / adhesive for the first layer is 0.1 to 1.0 kg / m ² , and more preferably 0.2 to 0.5 kg / m ² . If it is the said range, the protective sheet of a 2nd layer can be adhere | attached strongly. The means for applying the primer / adhesive of the first layer is not particularly limited, and for example, a roller, a brush, a trowel, a spatula, or the like can be used.

(2) 2nd process As a 2nd process, it bonds together so that the surface of the protective sheet of the 2nd layer may become a nonwoven fabric surface and a fiber yarn net may become a concrete surface from the 1st layer. When the fiber yarn net is bonded to the concrete surface, when stress is applied from the concrete surface, the stress is first received by the fiber yarn net, but the fiber yarn net is reinforced by being lined with a nonwoven fabric. The movement of the fiber yarns constituting the fabric is suppressed by the nonwoven fabric, and the peeling prevention performance is enhanced. The second layer protective sheet is attached immediately after the first layer primer / adhesive is applied and before the resin is dried. In order to uniformly impregnate and adhere the protective sheet of the second layer, it is attached using a spatula, a roller or the like while rolling from above the protective sheet of the second layer.

(3) Third Step As the third step, a third layer adhesive is applied from above the protective sheet. By applying the third layer adhesive, when the third layer adhesive is applied to the protective sheet, the third layer adhesive is impregnated into the protective sheet, and the first layer primer / adhesive is also bonded. Therefore, the first layer to the third layer are integrated to form a high-strength film. A preferable coating amount range of the third layer adhesive is 0.05 to 0.5 kg / m ² , and more preferably 0.1 to 0.3 kg / m ² . If it is the said range, the impregnation to the protective sheet of a 2nd layer will become enough. The adhesive used for the third layer is preferably the same resin as the primer / adhesive for the first layer. If it is the same resin, the adhesiveness with a 1st layer is also good, and it is convenient for integrating the protective sheet of a 2nd layer with resin. Moreover, since it can apply | coat before drying hardening, coating efficiency is good and construction time can also be shortened. The third layer adhesive can be applied immediately after the second layer protective sheet is pasted, and may be applied after the second layer protective sheet is pasted and cured. The means for painting is not particularly limited, and for example, a roller, a brush, a trowel, a spatula or the like can be used.

  4A-C show the construction method of one embodiment of the present invention. FIG. 4A is a process of forming the primer / adhesive of the first layer 22 on the surface of the concrete 21 by the roller 23. FIG. 4B is a process of bonding the second layer protective sheet 10 onto the first layer 22 using a spatula 24 or the like. FIG. 4C is a process of forming the third layer 25 adhesive on the second layer protective sheet 10 by the roller 23.

The present invention can be applied to any concrete surface whether it is outdoors or indoors. When the concrete surface is present outdoors, a fourth layer is further formed on the third layer in order to impart functions such as weather resistance and antifouling property to the anti-peeling layer formed from the first layer to the third layer. A finishing material may be applied. As the finishing material, it is preferable to use one-component or reaction-curable synthetic resin paint selected from the group consisting of epoxy resin, acrylic resin, polyurethane resin, fluorine resin, acrylic silicon resin and silicone resin. As the finishing material, an intermediate coating material and a top coating material may be applied repeatedly depending on the application. Further, an ultraviolet absorber, a light stabilizer, a pigment, a dispersant, a viscosity modifier, an antifoaming agent, a diluent and the like can be added to the finishing material. The range of the preferable coating amount of the finishing material is 0.05 to 0.5 kg / m ² , more preferably 0.1 to 0.3 kg / m ² . The means for painting is not particularly limited, and for example, a roller, a brush, a spray, or the like can be used.

  The same adhesive can be used for the adhesive of the first layer and the third layer. If it is the same adhesive agent, it is convenient to impregnate both adhesive agents into a concrete exfoliation prevention sheet and integrate them. Moreover, it is preferable from the point of coating efficiency to apply | coat the coating agent of a 1st layer, a 3rd layer, and a 4th layer with a roller or a spray.

  The protective sheet used in the second layer has a formability (a property that keeps bending along the uneven shape of the concrete), so it is difficult to float at corners and drainage parts, and an adhesive with low viscosity is used. it can. Adhesive adjusted to a viscosity of 10 mPa · s to 20,000 mPa · s and a thixotropy index of 1 to 7 can be used, and if it is within the above range, a second layer protective sheet is applied with a roller. A sufficient coating amount can be uniformly applied, and can be impregnated and adhered uniformly.

In addition, the viscosity measurement used the Brookfield type rotational viscometer prescribed | regulated to JISK7117-1 in the environment of 23 degreeC and 50% RH. For those of less than 10,000 mPa · s, BL type rotational viscometer, No. 4 rotor, 60 min ⁻¹ , for those of 10,000 to 100,000 mPa · s, BH type rotational viscometer, No. 6 rotor Alternatively, measurement was performed with a No. 7 rotor and 20 min ⁻¹ . As for the thixotropy index, the ratio of viscosities at two different rotor rotational speeds was determined using a Brookfield type rotational viscometer defined in JIS K7117-1 as in the viscosity measurement. Incidentally, of less than 10,000 mPa · s are, BL-type rotational viscometer, No. 4 rotor, 6min ^-1 / 60min ^-1, for those of 10,000~100,000mPa · s is, BH type rotational viscometer , No. 6 rotor or No. 7 rotor, measured at 2 min ⁻¹ / 20 min ⁻¹ .

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples.

<Measurement method of the punching test for preventing concrete peeling>
It measured according to the NEXCO structure construction management point and the test method 424-2009. First, as shown in FIG. 5A, a punched portion 32 having an inner diameter of 100 mm, a groove width of 5 mm, and a depth of 55 mm was formed in the center of a concrete block 31 having a length of 400 mm, a width of 600 mm, and a height of 60 mm by an air cutter for concrete. Reference numeral 33 denotes a groove portion (core removal portion). A protective sheet 30 was bonded to the surface of the concrete block 31 opposite to the punched portion 32. The construction area was 400 mm long and 600 mm wide. Next, as shown in FIGS. 5B-C, the punched portion 32 of the concrete block 31 is pressed as shown by an arrow and pressed at a speed of 1 mm / min until the punched portion 32 breaks, and after the breakage, 5 mm / min. Pressed with. The protective sheet 30 is pressed by the punched portion 32. This is shown in the chart in FIG. In FIG. 6, the test force is reduced at the stroke length of 10 mm because it is determined that the cylinder is temporarily stopped and the degree of destruction of the protective sheet is observed visually.

Example 1
(1) Protective sheet A fiber yarn net made by Toyobo Co., Ltd., product name “Dyneema”, fineness 1320 deci tex (1170 filaments) was used, and the thread spacing was 1/10 mm for both warp and width. The basis weight of the fiber yarn net was 26 g / m ² . As the nonwoven fabric, a polyester spunbond nonwoven fabric (manufactured by Unitika Ltd., trade name “Elves”, basis weight 15 g / m ² ) was used. The fiber yarn net and the nonwoven fabric were integrated by the method shown in FIG. As the adhesive, a urethane-based adhesive was used, and the adhesion amount was 24 g / m ² . The obtained protective sheet is shown in FIGS. 1A-B. The weight (weight per unit area) of this protective sheet was 65 g / m ² . In the obtained protective sheet, the shape of one fiber yarn net was flat, and was a tape shape having a width of 2.5 mm and a thickness of 0.2 mm.

(2) Construction method on concrete surface and measuring method of punching test A protective sheet was bonded to the concrete block 31 shown in FIG. 5A. An epoxy resin (manufactured by Atomix, trade name “Lifetex # 750”, viscosity 300 to 1,000 mPa · s, thixotropy index 1 to 2) was used as the primer and adhesive. Construction was carried out by the method shown in Table 1 below, and a punching test was conducted after 7 days of standard curing. The results of the punching test are summarized in FIG. Moreover, the chart which compares the result of the concrete peeling prevention punching test of the protection sheet of Example 1 of this invention and the comparative example 1 is shown in FIG.

(Comparative Example 1)
Instead of the protective sheet of Example 1, a fiber yarn made by Toyobo Co., Ltd., product name “Dyneema” 1320 deci tex was used, and a biaxial arrangement of 1/10 mm in both the vertical and horizontal intervals was used. The same experiment as in Example 1 was performed. This is an example without the nonwoven fabric in Example 1. The results of the punching test are summarized in FIG.

(Comparative Example 2)
The same experiment as Example 1 was performed except that the product name “Trione TSS-1810-Y” (triaxial net using vinylon fiber yarn) manufactured by Unitika Ltd. was used instead of the protective sheet of Example 1. . The results of the punching test are summarized in FIG.

(Comparative Example 3)
Using the product name “Trione TSS-1810-Y” (triaxial net using vinylon fiber yarn) manufactured by Unitika Ltd. in Comparative Example 2, the conventional method (manufactured by Atomix, method name “Lifetex V-FRP Method”) , NEXCO structure construction management procedure, peeling test, performance check completed construction method). Here, with a conventional construction method, six steps of a primer coating process, an adhesive coating process, a protective sheet applying process, an adhesive coating process, an intermediate coating material coating process, and a top coating material coating process are essential. In addition, the epoxy resin (Atomics company make, brand name "Lifetex V-SE (16)", the viscosity of 30,000-100,000 mPa * s, the thixotropy index 5-15) was used for the adhesive agent of a conventional construction method. Each step of Comparative Example 3 is as shown in Table 2. The results of the punching test are summarized in FIG. 9 and Table 3.

  As is clear from Table 3 and FIG. 10, the protective sheet (Example 1) in which the Dyneema biaxial array and the nonwoven fabric are integrated as a protective sheet, compared with only the Dyneema biaxial array (Comparative Example 1), The power has improved about 4 times. The load resistance of the nonwoven fabric itself is so low that it cannot be measured. From this, since the protective sheet of Example 1 of the present invention is in surface contact with the concrete surface, the adhesive strength is high, and when stress is applied from the concrete to the sheet, the nonwoven fabric moves the fiber yarns constituting the net. It was confirmed that it could suppress, exert a synergistic reinforcing effect, and increase the breaking strength.

  Moreover, the protective sheet of Example 1 showed the highest maximum load capacity compared with the sheet | seat of Comparative Examples 1-3, and the displacement was also the value which passed the specification. In addition, it was found that the protective sheet of Example 1 was very thin and the amount of adhesive impregnation could be reduced, so that the process could be simplified and the construction was easy, the construction efficiency was improved, and the construction period could be shortened. . Table 4 summarizes the comparison between Example 1 and Comparative Example 3 (conventional method).

1,15 Nonwoven fabrics 2a, 2b, 5a, 5b Warp yarns 3, 6 Weft yarns 4, 7 Fiber yarn net 8 Laminated sheet 9, 16 Guide rolls 10, 30 Protective sheet (concrete peeling prevention sheet)
11 Impregnation tank 12 Binder liquid 13, 14 Mangle (squeezing roll)
17, 18 Drying cylinder 19 Winding body 21 Concrete 22 First layer (primer and adhesive layer)
23 Roller 24 Spatula 25 Third layer (adhesive layer)
31 Concrete block 32 Punching part 33 Groove part (core cutting part)

Claims (9)

A concrete peeling prevention sheet for covering a concrete surface,
Fiber yarn net and non-woven fabric are bonded and integrated,
Each fiber yarn constituting the fiber yarn net is a tape yarn in which multifilament yarns composed of high-strength polyethylene fibers are arranged in a flat shape,
The fiber yarn net is a biaxial array composed of warp and weft yarns, and has a structure in which weft yarns are alternately sandwiched by warp yarns or a structure in which weft yarns are sandwiched by two upper and lower warp yarns. Concrete peeling prevention sheet characterized by. ^2. The concrete peeling prevention sheet according to claim 1 , wherein the fiber yarn net has a thread interval of 0.5 to 3 pieces / 10 mm for both warp and width, and a weight per unit area (weight per unit area) of 10 to 400 g / m ^2. . The weight per unit area of the nonwoven fabric (basis weight) concrete spalling prevention sheet according to claim 1 or 2 which is 10 to 50 g / m ^2. It said concrete spalling prevention sheet according to any one of claims 1 to 3 weight per unit area of concrete spalling prevention sheet (mass per unit area) is 20~450g / m ^2. A method of covering and fixing a concrete peeling prevention sheet on the concrete surface,
Apply primer and adhesive as the first layer on the concrete surface,
The concrete peeling prevention sheet according to any one of claims 1 to 4 is bonded as the second layer from above so that the fiber yarn net becomes a concrete surface,
A concrete peeling prevention method characterized in that an adhesive is applied as a third layer from above. The concrete peeling prevention method according to claim 5 , wherein the adhesive of the first layer and the third layer is the same adhesive, and the concrete peeling prevention sheet is impregnated with the both adhesives. The adhesive of the first layer and the third layer is an adhesive selected from the group consisting of epoxy resin, urethane resin, silicone resin, vinyl ester resin, polyester resin, acrylic resin, polyolefin resin, and polymer cement. 5. Concrete peeling prevention method according to 5 or 6 . The concrete peeling prevention method according to any one of claims 5 to 7, wherein the adhesive of the first layer and the third layer has a viscosity of 10 to 20,000 mPa · s and a thixotropy index of 1 to 7 . The concrete exfoliation preventing method according to any one of claims 5 to 8 , wherein the adhesive of the first layer and the third layer is applied by a roller.

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