JP5912203B1 - Curing sheet for concrete structure and method for producing concrete structure using the same - Google Patents

Abstract

The present invention relates to a curing sheet used in a method for producing a concrete structure that is affixed to the inner surface of a mold and is removed from the mold so as to be left on the concrete structure after placing the concrete and cured for a predetermined period. The mold can be easily demolded so as to remain on the concrete structure side when demolding, and it is closely attached to the concrete structure, and the breathing water can be suppressed. There is provided a curing sheet for a concrete structure capable of producing a concrete structure having high strength on the concrete surface and no fluttering on the concrete surface. A curing sheet comprising a non-water-permeable base material made of polypropylene resin or polyethylene terephthalate resin and having a slightly adhesive layer laminated on one surface, which is applied to the inner surface of a formwork, and casted with concrete. A curing sheet for a concrete structure characterized in that, when installed, the adhesion to the inner surface of the formwork is smaller than the adhesion to the concrete structure. [Selection] Figure 1

Description

The present invention relates to a method for manufacturing a concrete structure using a curing sheet that covers the surface of the concrete structure in order to cure the placed concrete.

  In order to manufacture a concrete structure, concrete is placed in a mold placed at a predetermined position, and after curing for a predetermined number of days, the mold is removed from the mold, and a curing sheet is applied to the concrete surface from which the mold has been removed. It was common to wet concrete for a period of time so that the hydration reaction progresses, but the curing sheet made of synthetic resin sheet has a low adhesion to the concrete structure, and it is cured on the vertical surface of the concrete structure. It is difficult to make the sheets adhere to each other, and there is a drawback that even if the sheets can be adhered, they are easily peeled and dropped over time.

  In order to eliminate the above drawbacks, various methods have been proposed in which a curing sheet is attached to the inner surface of a mold in advance when placing concrete. For example, “A material (plastic material) that has a greater adhesion to concrete than the dam frame and has a curing effect on concrete is attached in advance to the dam plate of the mold, and after placing the concrete, A concrete curing method in which a material adheres and remains on the concrete surface "(see, for example, Patent Document 1) has been proposed.

  However, the concrete used for placing has increased fluidity so that it can be filled to every corner in the mold, and contains excess water in excess of the amount required for the initial hardening of the cement. For this reason, after the concrete is placed, these surplus water collects on the concrete surface as breathing water, which may cause insufficient strength of the concrete surface or form bubbles (flapping) on the concrete surface.

  It has been proposed to use the above-mentioned breathing water effectively for curing and to laminate a pressure-sensitive adhesive layer on the curing sheet so that the surface of the concrete structure does not flutter. For example, “When a concrete structure is constructed, a film that prevents the volatilization of moisture from a plastic film or other film base material that adheres to the concrete surface from which the formwork has been removed after placing the concrete is removed. The film is provided with an adhesive layer for bonding to the formwork surface and the concrete surface on both sides, and the concrete is cast using this formwork by pasting it on the formwork in advance, and the concrete is hardened A film for curing a concrete structure characterized in that it functions without sticking to the concrete surface when the formwork is removed later, and can be easily removed manually after the function ”(for example, patent document) 2) is proposed.

  The curing sheet has a pressure-sensitive adhesive layer formed on both sides of a plastic film as a film base, but the surface of the concrete structure is in a wet state, and the adhesion to the surface of the concrete structure is small, so It was difficult to make it larger than the adhesive force, and it was difficult to leave the curing sheet on the surface of the concrete structure during demolding. In addition, the adhesive strength of the curing sheet to the surface of the concrete structure is small, so the effect of suppressing the generation of breathing water is small. It was difficult to suppress.

Japanese Patent Laid-Open No. 1-111961 JP 2014-66046 A

In view of the above problems, the object of the present invention is to paste a curing sheet on the inner surface of a mold in advance when placing concrete, and then cast the concrete in that state. A method of manufacturing a concrete structure in which a mold is removed so as to remain on the concrete structure side, and the concrete structure is cured for a predetermined period, and the curing sheet is left on the concrete structure side when demolding. The mold can be easily removed from the mold, and the curing sheet is in close contact with the concrete structure and can suppress breathing water. As a result, the concrete surface has high strength and the concrete surface does not flutter. It is to provide a method of manufacturing a concrete structure that can structures in production.

That is, the present invention
[1] Polypropylene resin is used on the inner surface of a concrete casting mold in which a sheet material having a linear expansion coefficient of 100 × 10 ⁻⁶ / ° C. or less, which is made of polypropylene resin or polyethylene terephthalate resin, is laminated on the inner surface. The adhesive layer is a curing sheet made of a resin or a polyethylene terephthalate-based resin and having a linear expansion coefficient of 100 × 10 ⁻⁶ / ° C. or less and a non-permeable adhesive layer laminated on one surface. An affixing step for adhering the sheet material so as to contact the sheet material, an injecting step for injecting concrete with the curing sheet being affixed, and a mold so that the curing sheet is left on the concrete structure side after the concrete is inlaid. Demolding process to demold the frame and curing process to cure the concrete structure for a specified period with the curing sheet left on the surface of the concrete structure Becomes, when the Da設concrete, a method of manufacturing a concrete structure, wherein the adhesion strength between the cured sheet and the mold inner surface is smaller than the adhesive force between the cured sheet and the concrete structure and,
[2] The method for producing a concrete structure according to claim 1, wherein the polypropylene-based resin is a propylene-based thermoplastic elastomer .

The structure of the method for producing a concrete structure of the present invention is as described above, and the mold can be easily removed so that the curing sheet remains on the concrete structure side after the concrete is placed. A concrete structure that can easily adhere to the surface of a concrete structure with an appropriate strength that does not peel off during curing, can be easily peeled off even after curing, has a large surface strength, and has no surface irregularity. Things can be easily manufactured.

It is sectional drawing which shows an example of the mold for concrete placement by which the sheet | seat material which consists of a polypropylene-type resin or a polyethylene terephthalate-type resin is laminated | stacked on the inner surface. It is sectional drawing which shows an example of the state which laid concrete on the inner surface of a formwork. It is sectional drawing which shows an example of the concrete structure after removing a formwork.

The curing sheet used in the present invention is a curing sheet in which a slightly adhesive layer is laminated on one surface of a water-impermeable substrate made of polypropylene resin or polyethylene terephthalate resin, sticking, and when the Da設concrete, adhesion between the mold inner surface is smaller than the adhesive force between the concrete structure.

  The water-impermeable base material is a sheet made of polypropylene resin or polyethylene terephthalate resin. Polypropylene resin sheets and polyethylene terephthalate resin sheets both have low linear expansion and are less likely to wrinkle due to changes in temperature, making them difficult to peel off. The polypropylene resin sheet is preferable because it is less likely to peel from the polypropylene resin sheet due to the generation of breathing water.

  The polypropylene-based resin is a polymer mainly composed of propylene. In addition to the propylene homopolymer, the polypropylene-based polymer is mainly α, such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene. -A copolymer with an olefin, a propylene-based thermoplastic elastomer, and the like are mentioned, and a propylene-based thermoplastic elastomer having high flexibility and excellent adhesion to the surface of a concrete structure is preferable. Moreover, these polypropylene resins may be used alone or in combination.

  The propylene-based thermoplastic elastomer is a polypropylene resin or a melt mixture or polymerization reaction product of an ethylene-propylene copolymer and an ethylene-propylene rubber. For example, the trade name “Prime TPO” manufactured by Prime Polymer Co., Ltd., Nippon Polypro Co., Ltd. The product name “Newcon”, the product name “Cataloy” manufactured by Sun Allomer, the product name “Zeras” manufactured by Mitsubishi Chemical Corporation, and the like can be given.

  Talc, fly ash, and / or cement may be added to the polypropylene resin so that the adhesion of the polypropylene resin sheet to the concrete structure is increased.

  The talc is a white or gray inorganic powder obtained by pulverizing talc, and is mainly composed of hydrous magnesium silicate. When the particle size of talc is increased, the formability of the sheet is lowered and the sticking property of the sheet to the surface of the concrete structure is lowered. Therefore, the average particle size is preferably 50 μm or less, more preferably 25 μm or less.

  The fly ash is produced as a by-product when pulverized coal is burned in a thermal power plant or the like, and is a mixture containing 50 to 70% by weight of silicon dioxide and 15 to 30% by weight of aluminum oxide as main components. As the particle size of fly ash increases, the formability of the sheet decreases and the stickability of the sheet to the surface of the concrete structure decreases. Therefore, the average particle size is preferably 50 μm or less.

  The cement is a hydraulic cement that has been conventionally used as a raw material for concrete and mortar, mainly Portland cement and Portland cement, mixed with blast furnace slag, siliceous mixture, fly ash, etc. Examples thereof include silica cement and fly ash cement, and Portland cement is preferable.

The Portland cement, tricalcium silicate (alite, 3CaO · _SiO 2), dicalcium silicate (belite, 2CaO · _SiO 2), calcium aluminate _{(aluminate, 3CaO · Al 2 O 3)} , calcium aluminosilicate It consists of ferrite (ferrite, 4CaO.Al ₂ O ₃ .Fe ₂ O ₃ ), calcium sulfate (gypsum, CaSO ₄ .2H ₂ O), etc., and is used as a raw material for concrete.

  Examples of the Portland cement include ordinary Portland cement, early strength Portland cement, ultra-early strength Portland cement, medium heat Portland cement, low heat Portland cement, sulfate resistant Portland cement, white Portland cement, and the most versatile. High general “ordinary cement”, and ordinary portland cement used for general construction / structure is preferable.

  When the particle size of the cement is increased, the formability of the sheet is lowered and the adhesion of the sheet to the surface of the concrete structure is lowered. Therefore, the average particle size is preferably 40 μm or less.

  When the amount of talc, fly ash and cement is reduced, the adhesion of the polypropylene resin sheet to the surface of the concrete structure is reduced, and when the amount is increased, the moldability of the sheet is reduced. 0.1-50 weight part is preferable, More preferably, it is 0.5-30 weight part. Further, talc, fly ash and cement may be used alone or in combination.

  In addition, a compounding agent generally added during the molding of a polypropylene resin sheet, for example, a crystal nucleating agent; a processing aid; a modifier; a lubricant; an antioxidant; a light stabilizer; an ultraviolet absorber; A weathering agent; a pigment; a coloring agent; an inorganic filler such as mica, calcium carbonate, and titanium oxide; and a plasticizer.

  The thickness of the water-impermeable substrate is not particularly limited, but if it becomes too thin, it becomes difficult to handle and easily breaks during use, and if it becomes too thick, handling becomes difficult and cost increases. 10-1000 micrometers is preferable, More preferably, it is 100-500 micrometers.

In addition, when the linear expansion coefficient of the non-permeable base material becomes large, wrinkles occur due to temperature changes while sticking to the surface of the concrete structure, and the curing sheet peels off, or the surface property of the concrete structure decreases. Therefore, it is 100 × 10 ⁻⁶ / ° C. or less .

  In addition, the curing sheet is preferably transparent or translucent so that the surface state of the concrete structure can be observed when the curing sheet is attached to the surface of the concrete structure. It is preferable that the amount of the talc, fly ash, Portland cement and compounding agent is controlled so as to be translucent.

  The method for producing the water-impermeable base material is not particularly limited, and examples thereof include conventionally known inflation methods, T-die methods, and the like. For example, the polypropylene resin, fly ash or Portland cement and, if necessary, a compounding agent. Or a mixture obtained by uniformly dispersing the mixture with a super mixer or the like, and extruding the pellet obtained by melting and extruding the mixture with a pelletizer and then cutting with a pelletizer, using an inflation method, a T-die method, etc. May be formed by the following. In addition, talc, fly ash, Portland cement, a compounding agent, etc. may create and add a masterbatch with polypropylene resin.

  The pressure-sensitive adhesive layer is a slightly pressure-sensitive adhesive layer in which a pressure-sensitive adhesive is laminated on one surface of a water-impermeable substrate. As the above-mentioned pressure-sensitive adhesive, any conventionally known pressure-sensitive adhesive can be used, and examples thereof include rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicon-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, and the like, and transparency and weather resistance. An acrylic pressure-sensitive adhesive such as the above is preferable.

  Since the pressure-sensitive adhesive layer is slightly tacky, the slightly-tacky pressure-sensitive adhesive may be laminated on the entire surface of the water-impermeable base material. Is formed into a spot, line, grid, or the like, or laminated on the entire surface of a water-impermeable substrate, and then a concavo-convex pattern such as a dot, line, or grid is formed on the surface to reduce adhesiveness. Is preferred.

  Further, since the microsphere adhesive is slightly adhesive, it can be used by being laminated on the entire surface of the non-permeable base material. As the microsphere adhesive, any conventionally known microsphere adhesive can be used. For example, an alkyl acrylate having 4 to 8 alkyl carbon atoms and methyl acrylate, styrene, vinyl acetate, or vinyl propionate. And the like are solution polymerized and then dispersed in water to obtain a suspension.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited, but when it is thinned, the effect of preventing the occurrence of wrinkles on the water-impermeable substrate due to the difference in linear expansion coefficient between the mold and the water-impermeable substrate when pasted on the inner surface of the mold When the thickness is reduced and the thickness is increased, the adhesive strength tends to increase. Therefore, the thickness is preferably 5 to 100 μm, more preferably 10 to 50 μm.

  In addition, when concrete is placed after the curing sheet is applied to the inner surface of the mold, the adhesive strength between the adhesive layer and the inner surface of the mold is less than the adhesive strength between the water-impermeable substrate and the concrete structure. In general, by a method according to JIS Z 0237, the 180 ° peel adhesive strength (SP adhesive strength) to the SUS 304 steel plate is 0.01 to 8.0 N / 20 mm width (tensile speed 300 mm / min). preferable.

  If the adhesion between the water-impermeable substrate and the concrete structure is smaller than the adhesive force between the adhesive layer and the inner surface of the mold, the curing sheet can be removed from the concrete structure when the mold is removed. Disappear. In addition, if the adhesive force is greater than the adhesive force between the adhesive layer and the inner surface of the mold, if the adhesive force is not sufficient, the edge of the curing sheet will peel off during demolding or curing, and the curing effect will decrease. On the contrary, if it is too large, it becomes difficult to peel off the curing sheet after completion of curing, and the concrete structure may be damaged. Therefore, the adhesive force between the water-impermeable base material and the concrete structure is 0, 1 to 80 N / 20 mm width (tensile speed 300 mm / min), which is larger than the adhesive force between the adhesive layer and the inner surface of the mold. Is preferred.

  In addition, the measuring method of the adhesive force of the said water-impermeable base material and a concrete structure is 180 degree peeling force (tensile speed of 300 mm / min) of the 20 mm width curing sheet with respect to a concrete structure. That is, after demolding, the curing sheet adhering to the concrete structure is cut out to 100 × 20 mm to obtain a measurement sample, and its end is fixed to the spring alone, and the spring alone is in the length direction of the curing sheet. The load is measured by pulling the sample in the 180 ° direction (parallel to the concrete structure) at a pulling speed of 300 mm / min until the sample is completely peeled off, and the maximum load is measured as the adhesive force.

  In order to improve the adhesion between the water-impermeable substrate and the concrete structure, a pressure-sensitive adhesive layer made of the above-mentioned pressure-sensitive adhesive is laminated on the other surface of the water-impermeable substrate (the surface in contact with the concrete structure). The pressure-sensitive adhesive layer may be laminated on the entire surface or may be partially laminated. Moreover, the double-sided adhesive tape or sheet | seat manufactured from the said adhesive may be laminated | stacked.

The method for producing a concrete structure of the present invention is for concrete placement in which a sheet material having a linear expansion coefficient of 100 × 10 ⁻⁶ / ° C. or less is laminated on the inner surface thereof, which is made of polypropylene resin or polyethylene terephthalate resin. A slightly adhesive pressure-sensitive adhesive layer is laminated on one surface of a water-impermeable base material made of polypropylene resin or polyethylene terephthalate resin and having a linear expansion coefficient of 100 × 10 ⁻⁶ / ° C. or less on the inner surface of the mold. An affixing step for adhering the curing sheet so that the adhesive layer is in contact with the sheet material, an injecting step for injecting concrete with the curing sheet being applied, and the curing sheet has a concrete structure Demolding process to demold the mold so that it is left on the object side, and the curing sheet is left on the surface of the concrete structure. It consists curing step of a predetermined time period curing the creation, when the Da設concrete, adhesive force between the cured sheet and mold inner surface is smaller than a adhesion between the curing sheet and the concrete structure.

  Next, the manufacturing method of the concrete structure of this invention is demonstrated with reference to drawings. FIG. 1 is a cross-sectional view showing an example of a concrete casting mold in which a sheet material made of polypropylene resin or polyethylene terephthalate resin is laminated on the inner surface, and FIG. 2 shows concrete casting on the inner surface of the mold. FIG. 3 is a cross-sectional view showing an example of a concrete structure after the mold is removed from the mold.

  The first step of the method for producing a concrete structure of the present invention is the curing of the concrete structure on the inner surface of a concrete casting mold in which a sheet material made of polypropylene resin or polyethylene terephthalate resin is laminated on the inner surface. This is a sticking step of sticking the sheet so that the pressure-sensitive adhesive layer is in contact with the sheet material.

  In FIG. 1, 1 is a mold, and 2 is a sheet material made of polypropylene resin or polyethylene terephthalate resin laminated on the inner surface of the mold 1. Any conventionally known formwork can be used as the formwork 1, and examples thereof include a formwork such as wood, plywood and metal plate, and the surface may be coated with paint.

  The sheet material 2 is made of polypropylene resin or polyethylene terephthalate resin. The polypropylene resin is a polymer mainly composed of propylene. In addition to the propylene homopolymer, ethylene, 1- Examples thereof include copolymers with α-olefins such as butene, 1-pentene, 1-hexene and 1-heptene, and propylene-based thermoplastic elastomers.

As the linear expansion coefficient of the sheet material 2 increases, the sheet material 2 is peeled off from the mold 1 due to a temperature change, or the curing sheet is deformed by applying a load to the curing sheet, so that wrinkles are generated. It is preferably close to the linear expansion coefficient of the water-permeable substrate , and is 100 × 10 ⁻⁶ / ° C. or less.

  The thickness of the sheet material 2 is not particularly limited, but it becomes difficult to handle when it is thinned, and when it is thickened, the cost becomes high and it becomes heavy and the workability is lowered, so 10 to 2000 μm is preferable. Further, the sheet material 2 is firmly fixed and laminated on the inner surface of the mold, but the lamination method is not particularly limited. For example, a method of bonding and fixing with an adhesive, mechanically using a staple, a nail, a screw, or the like. Examples include fixing methods.

  In FIG. 1, reference numeral 3 denotes a curing sheet, and a slightly adhesive pressure-sensitive adhesive layer 32 is laminated on one surface of a water-impermeable base material 31. The curing sheet 3 is affixed so that the adhesive layer 32 contacts the sheet material 2 and is affixed to the inner surface of the mold 1.

  The second step is a placing step of placing concrete with the curing sheet attached. As shown in FIG. 2, the concrete 4 is placed on the inner surface of the mold 1 on which the curing sheet 3 is attached so that the sheet material 2 and the pressure-sensitive adhesive layer 31 are in contact with the inner surface. After the concrete is placed, the concrete may be compacted with a vibrator or the like so that the concrete flows into every corner of the inner surface of the formwork. Further, in order to improve the adhesion strength of the curing sheet to the concrete structure, an uneven portion may be formed on the inner surface of the water-impermeable base material 31 so as to bite into the concrete, or the end portion is bent to The folded portion may be formed so as to be embedded in the.

  The third step is a demolding step. After the concrete is hardened to some extent after the concrete is placed, the mold 2 is demolded so that the curing sheet 3 remains on the concrete structure 41 side. Since the adhesive force between the curing sheet 3 and the sheet material 2 is smaller than the adhesion force between the curing sheet 3 and the concrete structure 41, the curing sheet 3 is left on the surface of the concrete structure as shown in FIG. The mold 1 and the sheet material 2 can be easily separated from the curing sheet 3.

  In addition, the sheet material 2 and the water-impermeable base material 31 are repeatedly expanded and contracted due to a temperature change from the placing process to demolding, but are relaxed by the adhesive layer, and the generation of wrinkles in the curing sheet 3 is suppressed. . Further, in order to more efficiently suppress the generation of wrinkles, it is preferable to make the linear expansion coefficients of the sheet material 2 and the water-impermeable base material 31 as close as possible.

  The fourth step is a curing step, and the concrete structure 41 is cured for a predetermined period with the curing sheet 3 left on the surface of the concrete structure 41 as shown in FIG. After completion of the curing, the concrete structure 41 is obtained by peeling the curing sheet 3.

  Next, examples of the present invention will be described, but the present invention is not limited to the examples.

(Examples 1 to 3, Comparative Examples 1 and 2)
Manufacture of curing sheet 30 parts by weight of polypropylene resin ( manufactured by Prime Polymer Co., Ltd., trade name “Prime Polypro E100GPL”, MFR = 0.9 g / 10 min, density = 0.9 g / cm ³ ) and talc (average particle size 3.5 μm, 70 parts by weight of an apparent density of 0.08 g / cm ³ ) was supplied to an extruder, melt-kneaded, extruded, and cut to obtain pellets (hereinafter referred to as “talc MB”).

70 parts by weight of polypropylene resin (manufactured by Prime Polymer Co., Ltd., trade name “Prime Polypro E100GPL”, MFR = 0.9 g / 10 min, density = 0.9 g / cm ³ ) and fly ass (manufactured by Chubu Electric Power Co., Ltd., particle diameter 1-100 μm, 30 parts by weight of an average particle diameter of 20 μm and an apparent density of 2.1 g / cm ³ were supplied to an extruder, melt kneaded, extruded, and cut to obtain pellets (hereinafter referred to as “fly ash MB”).

70 parts by weight of polypropylene resin (manufactured by Prime Polymer Co., Ltd., trade name “Prime Polypro E100GPL”, MFR = 0.9 g / 10 min, density = 0.9 g / cm ³ ) and Portland cement (manufactured by Taiheiyo Cement Co., Ltd., trade name “ordinary Portland cement” , 30 parts by weight of an average particle diameter of 10 μm and an apparent density of 3.16 g / cm ³ ) are supplied to an extruder, melt kneaded, extruded, and cut to obtain pellets (hereinafter referred to as “cement MB”). It was.

A predetermined amount of a propylene-based thermoplastic elastomer prime polymer company shown in Table 1, trade name “Prime TPO E-2900”, MFR = 2.8 g / 10 min, density = 0.91 g / cm ³ ), antistatic agent (Made by Kao Corporation, trade name “Elestroe Master”), weathering agent (hindered amine light stabilizer), “talc MB”, “fly ash MB” and “cement MB” are mixed, supplied to the extruder, and melt kneaded. Then, after extruding with a T-die, it was pressed and cooled with a rubber roll to obtain a non-water-permeable substrate having a thickness of 200 μm. The linear expansion coefficient of the obtained water-impermeable substrate was measured and the results are shown in Table 1.

  An acrylic solvent type pressure-sensitive adhesive (manufactured by Nichiei Chemical Co., Ltd.) is applied to one surface of the obtained water-impermeable base material in a grid shape having a convex portion width of 10 mm and a concave portion width of 5 mm, and then dried. A curing sheet was obtained by forming a 10 μm pressure-sensitive adhesive layer. Based on JIS Z 0237, 180 degree peeling adhesive strength (SP adhesive strength) with respect to SUS 304 steel plate was measured at a tensile speed of 300 mm / min, and the results are shown in Table 1.

  As Comparative Example 1, a polyethylene resin sheet having a thickness of 200 μm (trade name “Polysem” manufactured by Sekisui Molding Co., Ltd.), and as Comparative Example 2, a vinyl chloride resin sheet having a thickness of 200 μm (trade name “Svillon” manufactured by Sekisui Molding Co., Ltd.). Was used as a water-impermeable substrate. The linear expansion coefficient of each water-impermeable substrate was measured, and the results are shown in Table 1.

  In addition, an acrylic solvent type pressure-sensitive adhesive (manufactured by Nichiei Kako Co., Ltd.) is applied to one surface of each water-impermeable base material in a grid shape having a convex portion width of 10 mm and a concave portion width of 5 mm. A 10 μm thick adhesive layer was formed to obtain a curing sheet. Based on JIS Z 0237, 180 degree peeling adhesive strength (SP adhesive strength) with respect to SUS 304 steel plate was measured at a tensile speed of 300 mm / min, and the results are shown in Table 1.

Manufacture of concrete structures Portland cement (trade name “ordinary Portland cement”, manufactured by Taiheiyo Cement Co., Ltd., average particle diameter 10 μm, apparent density 3.16 g / cm ³ ) 35 parts by weight, water 17.5 parts by weight, mountain sand 73. 6 parts by weight and 10.2 parts by weight of crushed stone were mixed to obtain a concrete composition.

On the inner surface of a wooden mold with an inner diameter of 900 × 900 × 1800 mm, a sheet material made of polyethylene terephthalate resin with a thickness of 2 mm (manufactured by Sekisui Molding Co., Ltd., trade name “Estella”, linear expansion coefficient 35 × 10 ⁻⁶ / ° C.) Fixed and laminated with double-sided adhesive tape.

  Next, the curing sheet obtained was stuck on the sheet material, and the concrete composition was placed therein, and demolded after 5 days. During the mold removal, the curing sheets in Examples 1 to 3 and Comparative Examples 1 and 2 were in close contact with the concrete structure, and did not fall off from the surface of the concrete structure. Further, the adhesion force of the curing sheet to the concrete structure was measured and shown in Table 1.

  28 days after demolding, a 40 × 40 mm cutter joint was placed in the curing sheet, and when the cut curing sheet adhered to the concrete structure was observed, it adhered firmly in Examples 1 to 3. However, in Comparative Examples 1 and 2, it was peeled off during cutting.

  91 days after demolding, the curing sheets of Examples 1 to 3 were adhered to the surface of the concrete structure without generating bubbles, but the curing sheets of Comparative Examples 1 and 2 were dropped. Moreover, when the curing sheets of Examples 1 to 3 were peeled by hand, they were easily peeled off.

The method for producing a concrete structure of the present invention is suitably used in the field of civil engineering construction.

DESCRIPTION OF SYMBOLS 1 Formwork 2 Sheet material 3 Curing sheet 31 Adhesive layer 32 Water-impermeable base material 4 Concrete

Claims (2)

Polypropylene resin or polyethylene is used on the inner surface of a concrete casting mold, which is made of polypropylene resin or polyethylene terephthalate resin on the inner surface and laminated with a sheet material having a linear expansion coefficient of 100 × 10 ⁻⁶ / ° C. or less. An adhesive layer is a sheet material made of a terephthalate-based resin, in which a slightly-adhesive adhesive layer is laminated on one surface of a non-permeable base material having a linear expansion coefficient of 100 × 10 ⁻⁶ / ° C. or less. An affixing process in which the curing sheet is affixed, a placing process in which the concrete is placed with the curing sheet being affixed, and a mold is removed so that the curing sheet is left on the concrete structure side after the concrete is placed. The mold demolding process and the curing process for curing the concrete structure for a predetermined period with the curing sheet left on the surface of the concrete structure. Method for producing a concrete upon Da設and the curing sheet and the concrete structure and is smaller than adhesion force between the adhesive force between the mold inner surface is cured sheet and the concrete structure. The method for producing a concrete structure according to claim 1, wherein the polypropylene resin is a propylene thermoplastic elastomer .

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