Composition for concrete

Abstract

To provide a composition for concrete capable of obtaining a concrete structure having an improved performance balance between observability and appearance.SOLUTION: There is provided a composition for concrete capable of protecting, reinforcing or repairing concrete, wherein the transmittance at a wavelength of 1000 nm is 30% or more as measured by the prescribed transmittance measurement and the color difference ΔE*ab measured by the prescribed color difference measurement is 35 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a composition for concrete. [Background technology]

[0002] Various studies have been conducted on compositions for concrete that can protect, reinforce, or repair concrete. Examples of techniques related to compositions for concrete include those described in Patent Documents 1 and 2.

[0003] Patent Document 1 describes a composition that contains (1) a radical polymerizable monomer, (2) a copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound, (3) a polymerization initiator, and (4) a polymerization accelerator, and contains 1 to 10 parts by mass of (2) the copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound per 100 parts by mass of the total of (1) and (2). It is described that the composition described in Patent Document 1 provides a composition having excellent curability and transparency.

[0004] Patent Document 2 describes a surface protection composition to be applied to the surface of a porous body, which has an elongation of the surface protection layer of 0.5 mm or more as measured by a specified crack tracking test procedure in accordance with JSCE K 532. It is described that the surface protecting composition described in Patent Document 2 provides a surface protecting composition having excellent application stability. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-20983 [Patent Document 2] JP 2023-46902 A Summary of the Invention [Problem to be solved by the invention]

[0006] From the viewpoint of controlling deterioration of concrete, a composition for concrete is required that allows observation of cracks and the like on the surface of concrete after protection, reinforcement or repair of the concrete is performed.

[0007] Compositions for concrete are also required to provide good appearance to concrete after protecting, reinforcing or repairing the concrete.

[0008] Hereinafter, the degree to which cracks and the like on the surface of concrete can be observed after the concrete has been protected, reinforced, or repaired is also referred to as "observability." In addition, concrete after the concrete has been protected, reinforced, or repaired, that is, a structure having at least concrete and a layer made of a composition for concrete, is also referred to as a "concrete structure."

[0009] The present invention has been made in consideration of the above circumstances, and provides a composition for concrete that can provide a concrete structure having an improved balance of observational and appearance properties. [Means for solving the problem]

[0010] According to the present invention, there is provided the following composition, preferably a concrete composition.

[0011] [1] A composition for concrete capable of protecting, reinforcing or repairing concrete, comprising: The transmittance at a wavelength of 1000 nm measured by the following transmittance measurement 1 is 30% or more, Color difference ΔE measured by the following color difference measurement 1 * ab A composition for concrete, wherein the modulus is 35 or less. [Transmittance measurement 1] A hardened product made of the composition for concrete formed to a thickness of 1 mm is prepared as a transmittance measurement sample 1. The transmittance of the transmittance measurement sample 1 at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020) to obtain a transmittance value at a wavelength of 1000 nm. [Color difference measurement 1] A hardened product made of the concrete composition formed to a thickness of 1 mm is prepared as a color difference measurement sample 1. The color difference measurement sample 1 is placed on a standard white board, and chromaticity measurement is performed. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * The color difference measurement sample 1 is placed on a standard black board, and chromaticity is measured. * a * b * Lightness L in color space * (Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * (Blackboard) subtracted value is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) subtracted value is chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As the lightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * The color difference ΔE is calculated based on the following formula (1): * ab get.

number

[10] The composition for concrete according to any one of the above [1] to [9], which is a moisture-curing resin composition.

[11] The composition for concrete according to any one of the above [1] to

[10] , which is a paint.

[12] A coating film comprising the composition for concrete according to any one of the above [1] to

[11] .

[13] Concrete and A concrete structure comprising: a layer made of the composition for concrete according to any one of [1] to

[11] above.

[14] A composition set for concrete capable of protecting, reinforcing or repairing concrete, comprising: The present invention includes a primer composition (1), a concrete composition (2), and a topcoat composition (3), The transmittance at a wavelength of 1000 nm measured by the following transmittance measurement 2 is 30% or more, Color difference ΔE measured by the following color difference measurement 2 * ab A composition set for concrete, wherein the modulus is 35 or less. [Transmittance measurement 2] As the transmittance measurement sample 2, a layer made of the primer composition (1) formed to a thickness of 0.1 mm, a layer made of the hardened product of the concrete composition (2) formed to a thickness of 1 mm, and a layer made of the hardened product of the topcoat composition (3) formed to a thickness of 0.1 mm are laminated in this order to obtain a laminate. The transmittance of the transmittance measurement sample 2 at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020), and the transmittance value at a wavelength of 1000 nm is obtained. [Color difference measurement 2] As the color difference measurement sample 2, a laminate is obtained by laminating in this order a layer of the primer composition (1) formed to a thickness of 0.1 mm, a layer of the hardened product of the concrete composition (2) formed to a thickness of 1 mm, and a layer of the hardened product of the top coat composition (3) formed to a thickness of 0.1 mm. The color difference measurement sample 2 is placed on a standard white board, and chromaticity is measured according to CIE1976L. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * (White board) is obtained. The color difference measurement sample 2 is placed on a standard black board, and chromaticity measurement is performed. * a * b * Lightness L in color space * (Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * (Blackboard) subtracted value is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) subtracted value is chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As the brightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * The color difference ΔE is calculated based on the following formula (1): * ab get.

number

[15] forming a layer of a primer composition on a surface of concrete; and forming a layer made of a composition for concrete according to any one of [1] to

[11] above on the layer made of the composition for primer.

[16] The transmittance at a wavelength of 1000 nm measured by the following transmittance measurement 1 is 30% or more, Color difference ΔE measured by the following color difference measurement 1 * ab wherein the R is 35 or less. [Transmittance measurement 1] A cured product made of the composition formed to a thickness of 1 mm is prepared as transmittance measurement sample 1. The transmittance of the transmittance measurement sample 1 at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020) to obtain a transmittance value at a wavelength of 1000 nm. [Color difference measurement 1] A cured product of the composition is formed to a thickness of 1 mm as a color difference measurement sample 1. The color difference measurement sample 1 is placed on a standard white board, and chromaticity is measured. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * The color difference measurement sample 1 is placed on a standard black board, and chromaticity is measured. * a * b * Lightness L in color space * (Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * (Blackboard) subtracted value is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) subtracted value is chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As the brightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * The color difference ΔE is calculated based on the following formula (1):* ab get.

number

[17] The composition includes a primer composition (1), a composition (2), and a topcoat composition (3), The transmittance at a wavelength of 1000 nm measured by the following transmittance measurement 2 is 30% or more, Color difference ΔE measured by the following color difference measurement 2 * ab is 35 or less. [Transmittance measurement 2] As the transmittance measurement sample 2, a layer made of the primer composition (1) formed to a thickness of 0.1 mm, a layer made of the cured product of the composition (2) formed to a thickness of 1 mm, and a layer made of the cured product of the topcoat composition (3) formed to a thickness of 0.1 mm are laminated in this order to obtain a laminate. The transmittance of the transmittance measurement sample 2 at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020), and the transmittance value at a wavelength of 1000 nm is obtained. [Color difference measurement 2] As the color difference measurement sample 2, a laminate is obtained in which a layer of the primer composition (1) formed to a thickness of 0.1 mm, a layer of the cured product of the composition (2) formed to a thickness of 1 mm, and a layer of the cured product of the topcoat composition (3) formed to a thickness of 0.1 mm are laminated in this order. The color difference measurement sample 2 is placed on a standard white board, and chromaticity is measured according to CIE1976L. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * (White board) is obtained. The color difference measurement sample 2 is placed on a standard black board, and chromaticity measurement is performed. * a * b * Lightness L in color space *(Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * (Blackboard) subtracted value is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) subtracted value is chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As the lightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * The color difference ΔE is calculated based on the following formula (1): * ab get.

number

[0012] According to the present invention, there is provided a composition for concrete which makes it possible to obtain a concrete structure having an improved balance of performance in terms of observability and appearance. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing a schematic example of a preferred structure of a concrete structure according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described. The composition of the present invention is preferably a composition for concrete. The composition set of the present invention is preferably a composition set for concrete. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings are simplified and do not correspond to the actual dimensional ratio. The numerical range "A to B" represents A or more and B or less unless otherwise specified. In addition, in this specification, "(meth)acrylic" means "at least one of acrylic and methacrylic".

[0015] As described above, a concrete composition is required to provide a concrete structure with good observability and appearance. As a conventional technique for improving observation properties, for example, there is a technique described in Patent Document 1 in which a highly transparent composition is used as a composition for concrete.

[0016] According to the study by the present inventors, when a highly transparent composition is used as a composition for concrete, cracks and the like in the concrete can be confirmed even when the concrete is not being subjected to deterioration management, which may be undesirable in terms of appearance, in other words, the appearance of the concrete structure may be deteriorated. In other words, according to the study by the present inventors, it was found that there is a trade-off between observability and appearance in a concrete structure.

[0017] The present invention has been made in consideration of the above circumstances, and provides a composition for concrete that can provide a concrete structure having an improved balance of observational and appearance properties.

[0018] [Concrete composition] The composition for concrete of the present embodiment is a composition for concrete capable of protecting, reinforcing, or repairing concrete, and has a transmittance of 30% or more at a wavelength of 1000 nm measured by transmittance measurement 1 and a color difference ΔE * ab is 35 or less.

[0019] <Transmittance measurement 1> A hardened product made of a concrete composition formed to a thickness of 1 mm is prepared as transmittance measurement sample 1. The transmittance of transmittance measurement sample 1 at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020) to obtain a transmittance value at a wavelength of 1000 nm.

[0020] <Color difference measurement 1> A hardened concrete composition formed to a thickness of 1 mm is prepared as color difference measurement sample 1. The color difference measurement sample 1 is placed on a standard white board and chromaticity measurement is performed. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * (White board) is obtained. The color difference measurement sample 1 is placed on the standard black board, and the chromaticity is measured. * a * b * Lightness L in color space * (Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * (Blackboard) subtracted value is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) subtracted value is chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As the brightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * The color difference ΔE is calculated based on the following formula (1): * ab get.

[0021]

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[0022] Here, the transmittance measurement sample 1 and the color difference measurement sample 1 can be prepared, for example, by the method described in the Examples. Specifically, the concrete composition is applied to a PET film to a thickness of 1 mm, and the composition is allowed to stand at 23°C and a relative humidity of 50% for 7 days to harden the concrete composition, and then the PET film is peeled off.

[0023] As described above, in conventional concrete structures, there is a trade-off between observation ability and appearance. As a result of intensive research, the inventors have found for the first time that when the surface of a concrete structure is observed from the side of the layer made of a composition for concrete, the surface of the concrete cannot be observed in the visible light region, but the surface of the concrete can be observed in the near-infrared region, so long as the concrete structure has a concrete structure in which the surface of the concrete cannot be observed in the visible light region, but the surface of the concrete can be observed in the near-infrared region, then both observability and appearance can be achieved.

[0024] That is, according to the above-mentioned concrete structure, when the concrete structure is observed visually, the concrete surface cannot be observed, and cracks in the concrete cannot be observed, improving the appearance. On the other hand, when performing deterioration management of the concrete, for example, the concrete surface can be observed by irradiating it with light having a wavelength in the near-infrared region (e.g., 750 nm or more and 2500 nm or less, preferably 800 nm or more and 1500 nm or less) and observing the reflected light with a near-infrared camera, improving observability.

[0025] The present inventors have conducted extensive research into a concrete composition capable of realizing the above-mentioned concrete structure. As a result, the inventors have found that the transmittance at a wavelength of 1000 nm and the color difference ΔE * ab It has been found for the first time that by setting the above in a specific range, the balance between the performance of observation property and the performance of appearance is improved. That is, the inventors measured the transmittance and color difference ΔE* ab It was found that this is an effective design indicator for improving the balance between observability and appearance.

[0026] The composition for concrete of this embodiment has a transmittance of 30% or more at a wavelength of 1000 nm. From the viewpoint of further improving observability, the transmittance at a wavelength of 1000 nm of the composition for concrete of this embodiment is preferably 35% or more, more preferably 40% or more, even more preferably 50% or more, even more preferably 55% or more, even more preferably 58% or more, and even more preferably 60% or more, and the upper limit is not particularly limited, but may be, for example, 100% or less, 99% or less, 95% or less, or 90% or less.

[0027] The transmittance of the composition for concrete of this embodiment at a wavelength of 1000 nm can be controlled, for example, by each of the constituent components, such as the resin and pigment, contained in the composition for concrete. Specifically, it can be controlled by using a near-infrared transmitting pigment as the pigment contained in the composition for concrete; by adjusting the content of the pigment in the composition for concrete; etc.

[0028] From the viewpoint of further improving the appearance, the transmittance at a wavelength of 600 nm of the composition for concrete of this embodiment is preferably 58% or less, more preferably 55% or less, even more preferably 50% or less, even more preferably 40% or less, even more preferably 30% or less, even more preferably 20% or less, even more preferably 15% or less, and even more preferably 10% or less, and the lower limit is not particularly limited, and may be, for example, 0.0% or more, or 0.1% or more. The transmittance at a wavelength of 600 nm of the composition for concrete of this embodiment means the transmittance value at a wavelength of 600 nm obtained by measuring the transmittance at wavelengths from 300 nm to 1500 nm using a method similar to that of Transmittance Measurement 1.

[0029] Hereinafter, the lightness L of the concrete composition of this embodiment will be referred to as * (white board), chromaticity a * (white board), chromaticity b * (white board), brightness L * (Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard), Lightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * , color difference ΔE * ab These values ​​refer to values ​​obtained by color difference measurement 1.

[0030] The lightness L of the concrete composition of this embodiment * (White board) is not particularly limited, but may be, for example, 5 or more and 95 or less. The lightness L of the concrete composition of this embodiment * (Blackboard) is not particularly limited, but may be, for example, 2 or more and 95 or less, or 3 or more and 85 or less.

[0031] The lightness difference ΔL of the concrete composition of this embodiment * From the viewpoint of further improving the appearance, is preferably 40 or less, more preferably 35 or less, even more preferably 30 or less, even more preferably 20 or less, even more preferably 10 or less, and even more preferably 5 or less, and the lower limit is not particularly limited and may be, for example, -1 or more, -0.1 or more, or -0.05 or more.

[0032] Color a of the concrete composition of this embodiment * (White board) is not particularly limited, but may be, for example, -10 or more and 10 or less, or -5 or more and 5 or less. Color a of the concrete composition of this embodiment * (Blackboard) is not particularly limited, but may be, for example, between -10 and 10, or between -5 and 5. Color difference Δa of the concrete composition of this embodiment *is not particularly limited, and may be, for example, -10 or more and 10 or less, or -5 or more and 5 or less. Color difference Δa of the concrete composition of this embodiment * By setting the content of the polymer in the above range, the color of the composition for concrete can be made similar to the color of concrete (for example, gray).

[0033] Color b of the concrete composition of this embodiment * (White board) is not particularly limited, and may be, for example, -25 or more and 25 or less, -15 or more and 15 or less, -10 or more and 10 or less, or -5 or more and 5 or less. Color b of the concrete composition of this embodiment * (Blackboard) is not particularly limited, and may be, for example, -15 or more and 15 or less, -10 or more and 10 or less, or -5 or more and 5 or less. Color difference Δb of the concrete composition of this embodiment * is not particularly limited, and may be, for example, -20 or more and 20 or less, -10 or more and 10 or less, or -5 or more and 5 or less. Color difference Δb of the concrete composition of this embodiment * By setting the content of the polymer in the above range, the color of the composition for concrete can be made similar to the color of concrete (for example, gray).

[0034] Color difference ΔE of the concrete composition of this embodiment * ab is less than or equal to 35. Color difference ΔE of the concrete composition of this embodiment * ab From the viewpoint of further improving the appearance, is preferably 33 or less, more preferably 30 or less, even more preferably 27 or less, even more preferably 23 or less, even more preferably 20 or less, even more preferably 15 or less, even more preferably 10 or less, even more preferably 8 or less, even more preferably 5 or less, even more preferably 4 or less, and even more preferably 2 or less, and the lower limit is not particularly limited, but may be 0.01 or more, or 0.02 or more.

[0035] The lightness L of the concrete composition of this embodiment * (white board), chromaticity a * (white board), chromaticity b * (white board), brightness L * (Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard), Lightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * , color difference ΔE * ab can be controlled, for example, by each of the constituent components, such as the resin and the pigment, contained in the composition for concrete. Specifically, the composition for concrete can include one or more pigments selected from the group consisting of black-based pigments and white-based pigments; by adjusting the content of the pigment in the composition for concrete; etc.

[0036] The composition for concrete of the present embodiment is preferably a curing type resin composition. The curable resin composition is preferably any one selected from the group consisting of a moisture-curable resin composition and a room temperature-curable resin composition, and more preferably a moisture-curable resin composition.

[0037] The composition for concrete of the present embodiment is preferably a paint.

[0038] The concrete composition of the present embodiment is preferably liquid at 23°C.

[0039] The composition for concrete of the present embodiment is not particularly limited as long as it is a composition capable of protecting, reinforcing or repairing concrete, and is, for example, any composition selected from the group consisting of a composition for protecting the surface of concrete, a composition for impregnating the surface of concrete, etc., and among these, a composition for protecting the surface of concrete is preferable. The composition for concrete of the present embodiment may be a composition that can be used in a concrete surface protection method, a composition that can be used in a concrete reinforcement method, or a composition that can be used in a concrete spalling prevention method. The composition for concrete of the present embodiment is preferably used in the surface protection method described below.

[0040] The components contained in the concrete composition of this embodiment are not particularly limited, but preferably contain a resin (A) and a pigment (B), more preferably contain a resin (A), a pigment (B), silica particles, and a crosslinking agent, and even more preferably contain a resin (A), a pigment (B), silica particles, a crosslinking agent, and a light stabilizer.

[0041] Hereinafter, preferred components contained in the composition for concrete of the present embodiment will be specifically described.

[0042] <Resin (A)> The composition for concrete of the present embodiment preferably contains a resin (A). The resin (A) is not particularly limited, but preferably contains at least one selected from the group consisting of modified silicone resins, urethane resins, urea resins, urethane urea resins, epoxy resins, and (meth)acrylic resins, and more preferably contains a modified silicone resin.

[0043] The modified silicone resin refers to a polymer having two or more reactive silyl groups in the molecule, and includes those in which reactive silyl groups are added to a polymer that serves as the main chain.

[0044] In the modified silicone resin, examples of the polymer to which the reactive silyl group is added include polyether-based polymers such as polyoxyethylene, polyoxypropylene, and polyoxybutylene; aliphatic hydrocarbon-based polymers such as polyisoprene, polyisobutylene, and polybutadiene; acrylic polymers such as poly(meth)acrylic acid and poly(meth)acrylate; and polyester-based polymers. Among these, polyether-based polymers are preferred, polyoxyalkylene is more preferred, and polyoxypropylene is even more preferred.

[0045] The polymer backbone to which the reactive silyl group is added may be linear or branched, but is preferably linear.

[0046] The polymer to which the reactive silyl group is added may be used alone or in combination of two or more kinds.

[0047] In the modified silicone resin, examples of the reactive silyl group include an addition-reactive silyl group, a condensation-reactive silyl group, and a hydrolyzable silyl group. Specific examples include groups in which a reactive group such as a hydrogen atom, a hydroxyl group, an alkoxy group, a halogen atom, an acyloxy group, an alkenyloxy group, an oxime group, a ketoximate group, an amide group, an acid amide group, a mercapto group, or an aminooxy group is bonded to a silicon atom.

[0048] Preferred examples of the reactive silyl group include alkoxysilyl groups such as trimethoxysilyl group, dimethoxymethylsilyl group, dimethylmethoxysilyl group, triethoxysilyl group, diethoxymethylsilyl group, dimethylethoxysilyl group, dimethoxyphenylsilyl group, diphenylmethoxysilyl group, diethoxyphenylsilyl group, and diphenylethoxysilyl group; and polymerizable reactive silyl groups such as dialkylsilicone, alkylalkoxysilicone, dialkoxysilicone, diphenylsilicone, and alkoxyphenylsilicone in which these alkoxysilyl groups are bonded to the terminals. Of these, the dimethoxymethylsilyl group is more preferred.

[0049] The modified silicone resin preferably contains at least one selected from the group consisting of modified silicone resin A having two or more reactive silyl groups at its terminals (particularly both terminals) and modified silicone resin B having one reactive silyl group at its terminals (particularly both terminals), and more preferably contains both modified silicone resin A and modified silicone resin B.

[0050] The viscosity of modified silicone resin A at 23°C is preferably 100 mPa·s or more, more preferably 500 mPa·s or more, even more preferably 1000 mPa·s or more, and preferably 7000 mPa·s or less, more preferably 5000 mPa·s or less, even more preferably 3000 mPa·s or less. The viscosity of modified silicone resin B at 23°C is preferably 7500 mPa·s or more, more preferably 10000 mPa·s or more, even more preferably 20000 mPa·s or more, and preferably 50000 mPa·s or less, more preferably 45000 mPa·s or less, even more preferably 40000 mPa·s or less. The viscosity of the modified silicone resin in this embodiment refers to a value measured using a B-type rotational viscometer (for example, Brookfield Viscometer RVDV1M, manufactured by Eiko Seiki Co., Ltd.) under conditions of 23° C. and a rotation speed of 20 rpm.

[0051] The content ratio of modified silicone resin A to modified silicone resin B in the modified silicone resin (modified silicone resin A:modified silicone resin B) is, in mass terms, for example, 40:60 to 99:1, preferably 45:55 to 90:10, and more preferably 50:50 to 80:20.

[0052] The viscosity of resin (A) at 23°C is preferably 1000 mPa·s or more, more preferably 5000 mPa·s or more, even more preferably 8000 mPa·s or more, and preferably 100,000 mPa·s or less, more preferably 90,000 mPa·s or less, even more preferably 50,000 mPa·s or less, even more preferably 30,000 mPa·s or less. The viscosity of the resin (A) herein means a value measured using a B-type rotational viscometer (for example, Brookfield Viscometer RVDV1M, manufactured by Eiko Seiki Co., Ltd.) under conditions of 23° C. and a rotation speed of 20 rpm. When resin (A) is composed of two or more resins, the viscosity of resin (A) at 23° C. means the viscosity of a mixture of two or more resins.

[0053] As the resin (A), one type of resin may be used, or two or more types of resins may be used.

[0054] <Pigment (B)> The composition for concrete of the present embodiment preferably contains a pigment (B).

[0055] From the viewpoint of further improving the observation property, the pigment (B) preferably contains a near-infrared transmitting pigment. Here, the near-infrared transmitting pigment means a pigment that easily transmits light having a wavelength of 900 nm or more and 1200 nm or less.

[0056] Examples of near-infrared transmitting pigments include metal oxide pigments, calcium carbonate, phthalocyanine pigments, and azo pigments. Furthermore, the near-infrared transmitting pigment may be a so-called heat shielding pigment.

[0057] The pigment (B) preferably includes one or more pigments selected from the group consisting of a black pigment (B-1) and a white pigment (B-2), and more preferably includes a black pigment (B-1) and a white pigment (B-2).

[0058] The black pigment (B-1) is not particularly limited as long as it is a black pigment, but preferably contains at least one selected from the group consisting of metal oxide pigments, phthalocyanine pigments, azo pigments, melanin pigments, carbon black, metal oxynitride pigments, metal nitride pigments, bisbenzofuranone pigments, azomethine pigments, and perylene pigments, more preferably contains at least one selected from the group consisting of metal oxide pigments, phthalocyanine pigments, azo pigments, melanin pigments, and carbon black, and more preferably contains at least one selected from the group consisting of metal oxide pigments and phthalocyanine pigments. An example of the metal oxynitride pigment is titanium black. An example of the metal nitride pigment is titanium nitride.

[0059] The white pigment (B-2) is not particularly limited as long as it is a white pigment, but preferably contains at least one selected from the group consisting of calcium carbonate, titanium oxide, silica, alumina, zinc oxide, zirconia, glass, crosslinked (meth)acrylic particles, crosslinked polystyrene resin, melamine resin, phenolic resin, epoxy resin, polycarbonate, and fluorine-based compounds, more preferably contains at least one selected from the group consisting of calcium carbonate and titanium oxide, and more preferably contains calcium carbonate. Examples of the fluorine-based compound include magnesium fluoride and calcium fluoride.

[0060] The content of pigment (B) in the concrete composition of this embodiment, when the content of resin (A) in the concrete composition is 100 parts by mass, is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, even more preferably 0.1 parts by mass or more, even more preferably 1 part by mass or more, even more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less.

[0061] The content of the black pigment (B-1) in the composition for concrete of this embodiment is, relative to the content of the resin (A) in the composition for concrete of 100 parts by mass, preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, even more preferably 0.05 parts by mass or more, and is preferably 1.0 part by mass or less, more preferably 0.7 parts by mass or less, and even more preferably 0.5 parts by mass or less.

[0062] The content of the white pigment (B-2) in the concrete composition of this embodiment, relative to the content of the resin (A) in the concrete composition being 100 parts by mass, is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, even more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less.

[0063] <Silica> The composition for concrete of the present embodiment preferably contains silica particles from the viewpoint of preventing dripping of the composition for concrete. The content of silica particles in the concrete composition of this embodiment is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, relative to 100 parts by mass of the resin (A) in the concrete composition.

[0064] <Crosslinking agent> The concrete composition of the present embodiment preferably contains a crosslinking agent. The crosslinking agent is not particularly limited, but when a modified silicone resin is contained as the resin (A), it is preferable to contain a silane coupling agent.

[0065] Examples of silane coupling agents include aminosilane-based compounds such as 3-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane; epoxysilane-based compounds such as γ-glycidoxypropyltrimethoxysilane; vinylsilane-based compounds such as γ-(meth)acryloxypropyltrimethoxysilane; cationic silane-based compounds such as N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride; and phenylsilane-based compounds. Among these, aminosilane-based compounds are preferred, and 3-aminopropyltrimethoxysilane is more preferred.

[0066] The content of the crosslinking agent in the composition for concrete of this embodiment is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less, relative to 100 parts by mass of the resin (A) in the composition for concrete.

[0067] The crosslinking agents may be used alone or in combination of two or more.

[0068] <Light stabilizer> The concrete composition of the present embodiment preferably contains a light stabilizer. The light stabilizer is not particularly limited, but for example, a hindered amine light stabilizer can be used.

[0069] Examples of the hindered amine light stabilizer include N-OR type hindered amine compounds, NR type hindered amine compounds, and NH type hindered amine compounds. Here, R represents a hydrocarbon group, and N-OR type and NR type refer to those in which an OR group and an R group are bonded to a nitrogen atom of a piperidyl skeleton. In addition, NH type refers to those in which a hydrogen atom is bonded to a nitrogen atom of a piperidyl skeleton.

[0070] The content of the light stabilizer in the composition for concrete of this embodiment, relative to the content of the resin (A) in the composition for concrete of 100 parts by mass, is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 1.5 parts by mass or more, even more preferably 2 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, even more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

[0071] The light stabilizers may be used alone or in combination of two or more.

[0072] <Curing catalyst> The concrete composition of the present embodiment preferably contains a curing catalyst. The curing catalyst includes at least one selected from the group consisting of tin-based catalysts, titanium-based catalysts, aluminum-based catalysts, zinc-based catalysts, iron-based catalysts, phosphorus-based catalysts, and the like. When the resin (A) contains a modified silicone resin, it is preferable to use a curing catalyst that catalyzes the reaction of the reactive silyl group contained in the modified silicone resin. The content of the curing catalyst in the concrete composition of the present embodiment is an appropriate amount.

[0073] <Textile> The composition for concrete of the present embodiment may further contain fibers from the viewpoint of further improving the strength of a hardened product made of the composition. In particular, when the composition for concrete of the present embodiment is a composition for concrete capable of reinforcing or repairing concrete, it is preferable that the composition for concrete further contains fibers.

[0074] The fibers include, for example, at least one selected from the group consisting of glass fibers, (meth)acrylic fibers, polyethylene fibers, nylon 6 fibers, nylon 6,6 fibers, polyester fibers, polypropylene fibers, vinylon fibers, aramid fibers, BPO (polyparaphenylenebenzoxazole) fibers, and carbon fibers, and among these, glass fibers are preferred.

[0075] The fiber length of the fibers is, for example, 0.1 mm or more and 50 mm or less, and preferably 3 mm or more and 10 mm or less. The fiber diameter of the fibers is, for example, 0.1 μm or more and 30 μm or less, and preferably 4 μm or more and 10 μm or less. The cross-sectional shape of the fiber is not particularly limited, and may be a perfect circle or an ellipse. The fibers may be cut fibers or may be in the form of a sheet of woven or nonwoven fabric.

[0076] The total content of fibers in the concrete composition of this embodiment, when the total of non-volatile components in the concrete composition is 100 mass%, is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, even more preferably 1 mass% or more, and is preferably 15 mass% or less, more preferably 10 mass% or less, even more preferably 5 mass% or less.

[0077] <Other ingredients> The concrete composition of the present embodiment may further contain other components. The composition for concrete of the present embodiment may further contain, for example, an ultraviolet absorbing agent, an antioxidant, and the like. The contents of the other components are each appropriate amounts.

[0078] The total content of the resin (A) and pigment (B) in the composition for concrete of this embodiment is, when the total of the non-volatile components in the composition for concrete is 100 mass%, preferably 80 mass% or more, more preferably 85 mass% or more, even more preferably 90 mass% or more, and is preferably 98 mass% or less, more preferably 96 mass% or less.

[0079] The total content of the resin (A), pigment (B), silica, crosslinking agent and light stabilizer in the composition for concrete of this embodiment is, when the total of the non-volatile components in the composition for concrete is 100 mass%, preferably 85 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, even more preferably 97 mass% or more, and preferably 100 mass% or less.

[0080] The concrete composition of the present embodiment can be obtained, for example, by mixing the respective components.

[0081] [Concrete composition set] The concrete composition set of this embodiment is a concrete composition set capable of protecting, reinforcing or repairing concrete, and includes a primer composition (1), a concrete composition (2) and a topcoat composition (3), and has a transmittance of 30% or more at a wavelength of 1000 nm measured by transmittance measurement 2 and a color difference ΔE * ab is 35 or less.

[0082] <Transmittance measurement 2> As the transmittance measurement sample 2, a layer of the primer composition (1) formed to a thickness of 0.1 mm, a layer of the hardened product of the concrete composition (2) formed to a thickness of 1 mm, and a layer of the hardened product of the topcoat composition (3) formed to a thickness of 0.1 mm are laminated in this order to obtain a laminate. For the transmittance measurement sample 2, the transmittance at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020), and the transmittance value at a wavelength of 1000 nm is obtained.

[0083] <Color difference measurement 2> As the color difference measurement sample 2, a laminate is obtained in which a layer of the primer composition (1) formed to a thickness of 0.1 mm, a layer of the hardened product of the concrete composition (2) formed to a thickness of 1 mm, and a layer of the hardened product of the top coat composition (3) formed to a thickness of 0.1 mm are laminated in this order. The color difference measurement sample 2 is placed on a standard white board, and chromaticity measurement is performed according to CIE1976L. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * (White board) is obtained. The color difference measurement sample 2 is placed on the standard black board, and the chromaticity is measured. * a * b * Lightness L in color space * (Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * (Blackboard) subtracted value is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) subtracted value is chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As the brightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * The color difference ΔE is calculated based on the following formula (1): * ab get.

[0084]

number

[0085] The preferred numerical range of the transmittance at a wavelength of 1000 nm of the composition for concrete of this embodiment is the same as the preferred numerical range of the transmittance at a wavelength of 1000 nm of the composition for concrete of this embodiment.

[0086] The transmittance at a wavelength of 1000 nm of the concrete composition set of this embodiment can be controlled, for example, by each of the constituent components such as resin and pigment contained in each of the primer composition (1), the concrete composition (2), and the topcoat composition (3). Specifically, it can be controlled by using a near-infrared transmitting pigment as the pigment contained in the concrete composition (2); adjusting the content of the pigment in the concrete composition (2); etc.

[0087] The preferred range of the transmittance at a wavelength of 600 nm of the composition for concrete of this embodiment is the same as the preferred range of the transmittance at a wavelength of 600 nm of the composition for concrete of this embodiment. The transmittance at a wavelength of 600 nm of the concrete composition set of this embodiment means the transmittance value at a wavelength of 600 nm obtained by measuring the transmittance at wavelengths from 300 nm to 1500 nm using a method similar to that of transmittance measurement 2.

[0088] The lightness L of the concrete composition set of this embodiment * (white board), chromaticity a * (white board), chromaticity b * (white board), brightness L * (Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard), Lightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * , color difference ΔE * ab The preferred ranges of are the same as the preferred ranges of the concrete composition of this embodiment.

[0089] The lightness L of the concrete composition set of this embodiment* (white board), chromaticity a * (white board), chromaticity b * (white board), brightness L * (Blackboard), chromaticity a * (blackboard), chromaticity b * (Blackboard), Lightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * , color difference ΔE * ab can be controlled, for example, by each of the constituent components such as resin and pigment contained in each of the primer composition (1), the concrete composition (2), and the topcoat composition (3). Specifically, the concrete composition (2) contains one or more pigments selected from the group consisting of black pigments and white pigments; by adjusting the content of the pigment in the concrete composition (2); and the like.

[0090] The composition set for concrete in this embodiment is not particularly limited as long as it is a composition set capable of protecting, reinforcing or repairing concrete, and is, for example, any composition set selected from the group consisting of a composition set for protecting the surface of concrete, a composition set for surface impregnation of concrete, etc., and among these, a composition set for protecting the surface of concrete is preferable. The composition set for concrete of the present embodiment may be a composition set that can be used in a concrete surface protection method, a composition set that can be used in a concrete reinforcement method, or a composition set that can be used in a concrete spalling prevention method. The composition set for concrete of the present embodiment is preferably used in the surface protection method described below.

[0091] <Primer composition (1)> The primer composition (1) in the composition set for concrete of the present embodiment contains, for example, a resin. The resin contained in the primer composition (1) is not particularly limited, and may include, for example, one or more selected from the group consisting of (meth)acrylic resins, olefin resins, vinyl acetate resins, urethane resins, epoxy resins, aminated epoxy resins, urea resins, silicone resins, and modified resins thereof, and among these, preferably includes a modified silicone resin, and more preferably includes a silicone-modified (meth)acrylic copolymer resin.

[0092] The primer composition (1) may contain an organic solvent. The organic solvent includes, for example, polar organic solvents, more specifically, ether-based solvents, alcohol-based solvents, ketone-based solvents, ester-based solvents, and the like. From the viewpoint of further improving the film formation stability, the organic solvent may contain a high boiling point solvent having a boiling point of 50° C. or more, preferably 100° C. or more, more preferably 120° C. or more. The upper limit of the boiling point of the solvent is not particularly limited, but may be, for example, 300° C. or less or 200° C. or less.

[0093] The primer composition (1) may contain, for example, a filler, a pigment, an ultraviolet absorber, a light stabilizer, an antioxidant, a silane coupling agent, a thickener, etc. The content of each of these components is an appropriate amount.

[0094] The total content of non-volatile components contained in the primer composition (1), when the total content of all components contained in the primer composition (1) is taken as 100 mass%, is preferably 20 mass% or more, more preferably 30 mass% or more, and even more preferably 40 mass% or more, from the viewpoint of further improving the performance balance between film-formability and handleability, and is preferably 100 mass% or less, more preferably 70 mass% or less, and even more preferably 60 mass% or less, from the viewpoint of further improving the performance balance between film-formability and handleability.

[0095] <Concrete Composition (2)> Preferred aspects of the composition for concrete (2) in the composition set for concrete of this embodiment are the same as the preferred aspects of the composition for concrete of this embodiment.

[0096] <Topcoat composition (3)> The top coat composition (3) in the composition set for concrete of the present embodiment contains, for example, a resin. The resin contained in the topcoat composition (3) is not particularly limited, and may include, for example, one or more selected from the group consisting of fluororesin, (meth)acrylic resin, (meth)acrylic silicone resin, (meth)acrylic urethane resin, urethane resin, olefin resin, vinyl acetate resin, ethylene-vinyl acetate copolymer resin, silicone resin, and modified resins thereof, and among these, preferably includes (meth)acrylic urethane resin.

[0097] The topcoat composition (3) preferably contains a curing agent, such as an isocyanate-based curing agent.

[0098] The topcoat composition (3) may contain an organic solvent.

[0099] The topcoat composition (3) may contain, for example, a filler, a pigment, an ultraviolet absorber, a light stabilizer, an antioxidant, a silane coupling agent, a thickener, etc. The content of each of these components is an appropriate amount.

[0100] The total content of non-volatile components in the top coat composition (3), when the total content of all components in the top coat composition (3) is taken as 100 mass%, is preferably at least 20 mass%, more preferably at least 30 mass%, even more preferably at least 40 mass%, and is preferably 100 mass% or less, more preferably 70 mass% or less, even more preferably 60 mass% or less.

[0101] The primer composition (1), concrete composition (2), and topcoat composition (3) of the present embodiment can each be obtained by, for example, mixing the respective components.

[0102] [Paint film] The coating film of this embodiment is made of the composition for concrete of this embodiment.

[0103] The composition for concrete that forms the coating film of this embodiment may be an uncured product, a semi-cured product, or a cured product.

[0104] The thickness of the coating film in this embodiment is preferably 0.1 mm or more, more preferably 0.3 mm or more, even more preferably 0.5 mm or more, even more preferably 0.7 mm or more, and preferably 3 mm or less, more preferably 2.5 mm or less, even more preferably 2 mm or less, even more preferably 1.8 mm or less.

[0105] The total amount of non-volatile components of the composition for concrete in the coating film of this embodiment is preferably 0.5 kg / m 2 More preferably, 0.7 kg / m 2 More preferably, 1 kg / m 2 and preferably 2 kg / m 2 Less than or equal to 1.7 kg / m 2 The following is the result.

[0106] The coating film of the present embodiment can be obtained, for example, by applying a composition for concrete onto a substrate (concrete, a resin film, etc.).

[0107] [Concrete structure] FIG. 1 is a cross-sectional view showing a schematic example of a preferable structure of the concrete structure of the present embodiment. The concrete structure 100 comprises concrete 50 and a layer 10 made of a concrete composition.

[0108] An example of the concrete 50 is a part of the concrete that constitutes an elevated bridge.

[0109] A preferred embodiment of the layer 10 made of a composition for concrete is similar to the coating film of this embodiment.

[0110] The concrete structure 100 may further comprise other layers. Other layers include a layer 20 made of a primer composition, a layer 30 made of a topcoat composition, and the like.

[0111] When the concrete structure 100 further comprises a layer 20 made of a primer composition, the concrete structure 100 preferably comprises, in this order, concrete 50, a layer 20 made of a primer composition, and a layer 10 made of a composition for concrete, and more preferably comprises, in this order, concrete 50, a layer 20 made of a primer composition, and a layer 10 made of a composition for concrete, with each layer being in direct contact with the other.

[0112] When the concrete structure 100 further comprises a layer 30 of a topcoat composition, it is preferable that the concrete structure 100 comprises, in this order, concrete 50, a layer 10 of a composition for concrete, and a layer 30 of a topcoat composition, and it is more preferable that the concrete structure 100 comprises, in this order, concrete 50, a layer 10 of a composition for concrete, and a layer 30 of a topcoat composition, with each layer being in direct contact with the other layers.

[0113] When the concrete structure 100 further comprises a layer 20 of a primer composition and a layer 30 of a topcoat composition, the concrete structure 100 preferably comprises, in this order, concrete 50, a layer 20 of a primer composition, a layer 10 of a concrete composition, and a layer 30 of a topcoat composition, and more preferably comprises, in this order, concrete 50, a layer 20 of a primer composition, a layer 10 of a concrete composition, and a layer 30 of a topcoat composition, with each layer being in direct contact with the other layers.

[0114] The layer 20 made of the primer composition is, for example, a layer made of the primer composition (1) in the composition set for concrete of this embodiment.

[0115] The primer composition forming the layer 20 made of the primer composition may be an uncured product, a semi-cured product, or a cured product.

[0116] The total amount of non-volatile components of the primer composition in the layer 20 made of the primer composition is preferably 0.03 kg / m 2 More preferably, 0.05 kg / m 2 and preferably 0.3 kg / m 2 Less than or equal to 0.2 kg / m 2 Less than 0.1 kg / m, more preferably 0.1 kg / m 2 The following is the result.

[0117] The layer 30 made of a top coat composition is, for example, a layer made of the top coat composition (3) in the composition set for concrete of this embodiment.

[0118] The topcoat composition forming layer 30 made of the topcoat composition may be an uncured product, a semi-cured product, or a cured product.

[0119] The total amount of non-volatile components of the topcoat composition in the layer 30 of the topcoat composition is preferably 0.03 kg / m 2 More preferably, 0.05 kg / m 2 More preferably, 0.07 kg / m 2 and preferably 0.3 kg / m 2 Less than or equal to 0.2 kg / m 2 The following is the result.

[0120] The concrete structure 100 can be obtained, for example, by applying a concrete composition onto concrete 50 to form a layer 10 made of the concrete composition. When the concrete structure 100 further includes a layer 20 made of a primer composition and a layer 30 made of a topcoat composition, for example, the primer composition can be applied onto concrete 50 and dried to form layer 20 made of the primer composition, layer 10 made of a concrete composition can be formed on layer 20 made of the primer composition, and a topcoat composition can be applied onto layer 10 made of the concrete composition and dried to form layer 30 made of the topcoat composition, thereby obtaining the concrete structure 100.

[0121] [Surface protection method] The surface protection method of this embodiment includes the steps of forming a layer of a primer composition on the surface of concrete, and forming a layer of the concrete composition of this embodiment on the layer of primer composition.

[0122] The surface protection method of this embodiment includes a step of forming a layer made of a primer composition on the surface of concrete. A preferred embodiment of the layer made of the primer composition is the same as the preferred embodiment of the layer 20 made of the primer composition in the concrete structure 100 .

[0123] The method for forming a layer made of a primer composition on the surface of concrete is not particularly limited, but an example thereof includes a method in which the primer composition is applied to the surface of concrete and then dried.

[0124] The surface protection method of the present embodiment includes a step of forming a layer made of the composition for concrete of the present embodiment on a layer made of the composition for primer. A preferred embodiment of the layer made of a composition for concrete is the same as the preferred embodiment of the layer 10 made of a composition for concrete in the concrete structure 100 .

[0125] The method for forming a layer of a composition for concrete on a layer of a composition for primer is not particularly limited, but an example thereof includes a method of applying a composition for concrete on a layer of a composition for primer.

[0126] From the viewpoint of further improving weather resistance, the surface protection method of this embodiment may further include a step of forming a layer made of a topcoat composition on the layer made of the composition for concrete. A preferred embodiment of the layer made of the topcoat composition is the same as the preferred embodiment of the layer made of the topcoat composition in the concrete structure 100 .

[0127] The method for forming a layer of a topcoat composition on a layer of a concrete composition is not particularly limited, but an example of the method includes applying a topcoat composition onto the layer of a concrete composition and drying it.

[0128] [Deformation management method] The method for managing deterioration of concrete in this embodiment includes a step of irradiating the surface of the concrete structure 100 on the side of the layer 10 made of a composition for concrete with light having a wavelength in the near-infrared region.

[0129] The wavelength of the near infrared region is, for example, 750 nm or more and 2500 nm or less, preferably 800 nm or more and 1500 nm or less.

[0130] The method for managing concrete deterioration in this embodiment preferably includes a step of observing the surface of concrete 50 by irradiating light with a wavelength in the near-infrared region onto the surface of concrete structure 100 facing layer 10 made of a concrete composition, and observing the reflected light with a near-infrared camera.

[0131] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of the present invention are included in the present invention. EXAMPLES

[0132] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0133] [Raw materials] First, the raw materials constituting the concrete composition will be described.

[0134] <Resin (A)> Modified silicone resin 1 (manufactured by Asahi Kasei Wacker Silicone Co., Ltd., product name: GENIOSIL XB502, viscosity at 23°C (measured using a B-type rotational viscometer (manufactured by Eiko Seiki Co., Ltd., product name: Brookfield viscometer RVDV1M) at a rotation speed of 20 rpm): 1300 mPa·s, modified silicone resin having two or more silicon atoms bonded to methoxy groups at each end, having a polyoxypropylene structure as a polyether polymer, and having a dimethoxymethylsilyl group as a reactive silyl group) Modified silicone resin 2 (manufactured by Asahi Kasei Wacker Silicone Co., Ltd., product name: GENIOSIL STP-E30, viscosity at 23°C (measured using a B-type rotational viscometer (manufactured by Eiko Seiki Co., Ltd., product name: Brookfield viscometer RVDV1M) at a rotation speed of 20 rpm): 30,000 mPa s, modified silicone resin having one silicon atom bonded to a methoxy group at each end, having a polyoxypropylene structure as a polyether polymer, and having a dimethoxymethylsilyl group as a reactive silyl group)

[0135] The viscosity at 23°C of a resin obtained by mixing 70 mass% of modified silicone resin 1 and 30 mass% of modified silicone resin 2 was 10,000 mPa s. Here, the viscosity at 23°C refers to a value measured using a B-type rotational viscometer (manufactured by Eiko Seiki Co., Ltd., product name: Brookfield Viscometer RVDV1M) at a rotation speed of 20 rpm.

[0136] <Black pigment (B-1)> Black pigment 1 (manufactured by Dainichiseika Color & Chemicals Co., Ltd., product name: Dipyroxide Black #9583, metal oxide pigment (iron-cobalt-aluminum), near infrared transmitting pigment, particle size: 0.06 μm) Black pigment 2 (manufactured by Dainichi Seika Chemicals Co., Ltd., product name: Chromofine Black A1103, phthalocyanine pigment, near infrared transmitting pigment) Black pigment 3 (manufactured by Denka Co., Ltd., product name: DENKA BLACK Li Li-100, acetylene black)

[0137] <White pigment (B-2)> White pigment 1 (Takehara Chemical Industry Co., Ltd., product name: NEOLIGHT SP, calcium carbonate, near infrared transmitting pigment, particle size: 0.08 μm) White pigment 2 (manufactured by Ishihara Sangyo Kaisha, Ltd., product name: TIPAQUE PFC105, titanium oxide, particle size: 0.28 μm)

[0138] <Silica particles> Silica particles 1 (manufactured by Wacker Asahi Kasei Silicone Co., Ltd., product name: HDK H18, particle size: 10 nm)

[0139] <Crosslinking agent> Crosslinking agent 1 (manufactured by Wacker Asahi Kasei Silicone Co., Ltd., product name: GENIOSIL GF96, 3-aminopropyltrimethoxysilane)

[0140] <Light stabilizer> Light stabilizer 1 (manufactured by BASF Japan Ltd., product name: Tinuvin B75, a mixture of UV absorber, NR-type hindered amine light stabilizer, and antioxidant)

[0141] [Examples 1 to 14 and Comparative Examples 1 to 9] Each raw material other than the crosslinking agent was weighed based on the formulation shown in Tables 1 and 2, and each raw material was stirred for 5 minutes to obtain the base material. The obtained base agent and crosslinking agent were mixed according to the formulations shown in Tables 1 and 2 to obtain concrete compositions, respectively.

[0142] [Measurement and Evaluation] Measurements and evaluations of the compositions for concrete obtained in Examples 1 to 14 and Comparative Examples 1 to 9 are described below.

[0143] <Transmittance measurement> The concrete composition was applied to a PET film to a thickness of 1 mm, and the concrete composition was allowed to harden at 23°C and a relative humidity of 50% for 7 days. The PET film was then peeled off to obtain a sample for transmittance measurement. The transmittance of the obtained sample for transmittance measurement was measured in the wavelength range of 300 nm to 1500 nm in accordance with JIS K 0115 (2020) using a spectrophotometer (manufactured by Shimadzu Corporation, product name: SolidSpec-3700). From the obtained transmittance measurement results, the transmittance values ​​at a wavelength of 1000 nm and at a wavelength of 600 nm were obtained.

[0144] <Color difference measurement> The concrete composition was applied to a PET film to a thickness of 1 mm, and the concrete composition was allowed to harden at 23°C and a relative humidity of 50% for 7 days. The PET film was then peeled off to obtain a sample for color difference measurement.

[0145] The color difference measurement sample is placed on a standard white board (an accessory of the spectrophotometer), and the chromaticity is measured using a spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd., product name: NF555). * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * (White board) was obtained.

[0146] The color difference measurement sample was placed on a standard blackboard (an accessory to the spectrophotometer), and the chromaticity was measured using a spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd., product name: NF555). * a * b * Lightness L in color space * (Blackboard), chromaticity a* (blackboard), chromaticity b * (Blackboard) each.

[0147] Next, the lightness L * (Whiteboard) to Lightness L * (Blackboard) subtracted value is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) subtracted value is chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As the lightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * The color difference ΔE was calculated based on the following formula (1): * ab obtained.

[0148]

number

[0149] <Appearance evaluation> First, preparation of a sample for evaluating appearance will be described.

[0150] <Preparation of samples for appearance evaluation> (Primer composition) The primer composition used was 8SQ-1052 (manufactured by Taisei Fine Chemical Co., Ltd.) The primer composition is a mixture of silicone-modified acrylic copolymer and methoxypropyl acetate (PGMAC, boiling point 146°C), with a non-volatile content of 45% and a viscosity of 600 mPa s.

[0151] (Making concrete slabs) In accordance with the method for preparing test substrates in JSCE K 511, mortar with a water / cement ratio of 50% and a sand / cement ratio of 3 was placed in a metal formwork with inner dimensions of 70 mm length x 150 mm width x 10 mm thickness, and cured for 24 hours at a temperature of 20±2°C and a relative humidity of 80% or more, and then removed from the formwork, and cured in water for 6 days at a temperature of 20±2°C. After the underwater curing was completed, the concrete plate was cured for 7 days or more at a temperature of 23±2°C and a relative humidity of 50±5% to obtain a concrete plate. A temporary fixing tape was attached to one side of the obtained concrete plate, and the side opposite to the side where the temporary fixing tape was attached was hit with a hammer to create cracks. Next, the temporary fixing tape was peeled off from the concrete plate. Here, the cracks in the concrete were 0.1 mm or more and 5 mm or less in width and 5 mm or more and 100 mm or less in length. In addition, there were 15 cracks in the concrete.

[0152] (Preparation of samples for appearance evaluation) The primer composition was applied to the cracked surface of the concrete plate at a coating weight of 0.15 kg / m 2 and dried for 24 hours at 23°C and a relative humidity of 50% to form a layer of the primer composition. Next, a composition for concrete was applied on the layer of the primer composition in an amount of 1.5 kg / m 2 and then allowed to stand at 23°C and 50% relative humidity for 7 days to harden the composition for concrete, forming a layer made of the composition for concrete, thereby obtaining a sample for evaluating appearance. In other words, the sample for evaluating appearance is a laminate having a three-layer structure of "concrete board / layer made of composition for primer / layer made of composition for concrete".

[0153] The obtained sample for evaluating appearance was visually observed from the side of the layer made of the concrete composition, and the appearance was evaluated based on the following criteria. A: No cracks are observed in the concrete slab. B: Some cracks are observed in the concrete slab, but the cracks are not noticeable. C: Cracks are observed in the concrete slab and are noticeable.

[0154] <Evaluation of observability> The same sample as the sample for evaluating appearance was used as the sample for evaluating observation properties. The surface of the sample for evaluating the observability on the side of the layer made of the concrete composition was irradiated with light of 900 nm using a halogen lamp, and the reflected light was observed with a near-infrared camera. The observability was evaluated based on the following criteria. A: The surface of the concrete slab is clearly visible, and cracks can be observed, making them easy to observe. B: The surface of the concrete slab is visible and cracks can be observed, but the cracks are more difficult to observe than in criterion A. C: The surface of the concrete slab is not visible, so no cracks can be observed.

[0155] <Overall rating> The overall evaluation of appearance and observation was made based on the following criteria. AA: The evaluation results of both appearance and observation were A. A: One of the evaluation results for appearance and observability was A, and the other was B. B: The evaluation results for both appearance and observability are B. C: At least one of the evaluation results of appearance and observability is C.

[0156] The compositions for concrete obtained in Examples 1 to 14 and Comparative Examples 1 to 9 were subjected to the above-mentioned measurements and evaluations, and the results are shown in Tables 1 and 2.

[0157] [Table 1]

[0158] [Table 2]

[0159] It can be seen from Tables 1 and 2 that the concrete compositions of the Examples have better results in the overall evaluation of appearance and observability than the Comparative Examples. In other words, it can be seen that the concrete composition of the present embodiment improves the balance of the performance of the observability and appearance of the resulting concrete structure. [Explanation of symbols]

[0160] 10 Layer made of concrete composition 20 Layer made of primer composition 30 Layer consisting of topcoat composition 50 Concrete 100 Concrete Structure

Claims

1. A composition for concrete capable of protecting, reinforcing or repairing concrete, comprising: The transmittance at a wavelength of 1000 nm measured by the following transmittance measurement 1 is 30% or more, Color difference ΔE measured by the following color difference measurement 1 * ａｂ A composition for concrete, wherein the viscosity is 35 or less. [Transmittance measurement 1] A hardened product made of the concrete composition formed to a thickness of 1 mm is prepared as a transmittance measurement sample 1. The transmittance of the transmittance measurement sample 1 at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020) to obtain a transmittance value at a wavelength of 1000 nm. [Color difference measurement 1] A hardened product of the concrete composition formed to a thickness of 1 mm is prepared as a color difference measurement sample 1. The color difference measurement sample 1 is placed on a standard white board, and chromaticity measurement is performed. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * (Whiteboard) is obtained respectively. The color difference measurement sample 1 was placed on a standard blackboard, and chromaticity was measured. * a * b * Lightness L in color space * (Blackboard), chromaticity a * (blackboard), chromaticity b * (blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * The value obtained by subtracting (blackboard) is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) is subtracted and the chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As a result, the brightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * respectively. The color difference ΔE is calculated based on the following formula (1): * ａｂ get. [0010]

2. 2. The concrete composition according to claim 1, comprising a resin (A) and a pigment (B).

3. 3. The concrete composition according to claim 2, wherein the resin (A) comprises at least one selected from the group consisting of modified silicone resins, urethane resins, urea resins, urethane urea resins, epoxy resins, and (meth)acrylic resins.

4. 4. The composition for concrete according to claim 2, wherein the content of the pigment (B) in the composition for concrete is 0.005 parts by mass or more and 40 parts by mass or less when the content of the resin (A) in the composition for concrete is 100 parts by mass.

5. The concrete composition according to claim 2 or 3, wherein the pigment (B) comprises a near-infrared transmitting pigment.

6. The concrete composition according to claim 2 or 3, wherein the pigment (B) comprises one or more selected from the group consisting of black pigments (B-1) and white pigments (B-2).

7. The concrete composition according to claim 6, wherein the black pigment (B-1) comprises at least one selected from the group consisting of metal oxide pigments, phthalocyanine pigments, azo pigments, melanin pigments, carbon black, metal oxynitride pigments, metal nitride pigments, bisbenzofuranone pigments, azomethine pigments, and perylene pigments.

8. 7. The concrete composition according to claim 6, wherein the white pigment (B-2) comprises at least one selected from the group consisting of calcium carbonate, titanium oxide, silica, alumina, zinc oxide, zirconia, glass, crosslinked (meth)acrylic particles, crosslinked polystyrene resin, melamine resin, phenolic resin, epoxy resin, polycarbonate, and fluorine-based compounds.

9. The lightness difference ΔL measured by the color difference measurement 1 * The concrete composition according to claim 1 or 2, wherein the viscosity is 40 or less.

10. 3. The composition for concrete according to claim 1, which is a moisture-curing resin composition.

11. 3. The composition for concrete according to claim 1, which is a paint.

12. A coating film comprising the composition for concrete according to claim 1 or 2.

13. Concrete and A concrete structure comprising a layer made of the concrete composition according to claim 1 or 2.

14. A composition set for concrete capable of protecting, reinforcing or repairing concrete, comprising: The present invention includes a primer composition (1), a concrete composition (2), and a topcoat composition (3), The transmittance at a wavelength of 1000 nm measured by the following transmittance measurement 2 is 30% or more, Color difference ΔE measured by the following color difference measurement 2 * ａｂ A composition set for concrete, wherein the viscosity is 35 or less. [Transmittance measurement 2] A laminate is obtained as a transmittance measurement sample 2, in which a layer of the primer composition (1) formed to a thickness of 0.1 mm, a layer of the cured product of the concrete composition (2) formed to a thickness of 1 mm, and a layer of the cured product of the topcoat composition (3) formed to a thickness of 0.1 mm are laminated in this order. The transmittance of the transmittance measurement sample 2 at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020), and the transmittance value at a wavelength of 1000 nm is obtained. [Color difference measurement 2] As the color difference measurement sample 2, a laminate is obtained in which a layer of the primer composition (1) formed to a thickness of 0.1 mm, a layer of the hardened product of the concrete composition (2) formed to a thickness of 1 mm, and a layer of the hardened product of the top coat composition (3) formed to a thickness of 0.1 mm are laminated in this order. The color difference measurement sample 2 is placed on a standard white board, and chromaticity measurement is performed to obtain a value according to CIE1976L. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * (Whiteboard) is obtained respectively. The color difference measurement sample 2 is placed on a standard blackboard, and the chromaticity is measured. * a * b * Lightness L in color space * (Blackboard), chromaticity a * (blackboard), chromaticity b * (blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * The value obtained by subtracting (blackboard) is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) is subtracted and the chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As a result, the brightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * respectively. The color difference ΔE is calculated based on the following formula (1): * ａｂ get. [0025]

15. forming a layer of a primer composition on a surface of concrete; and forming a layer made of the composition for concrete according to claim 1 or 2 on the layer made of the composition for primer.

16. The transmittance at a wavelength of 1000 nm measured by the following transmittance measurement 1 is 30% or more, Color difference ΔE measured by the following color difference measurement 1 * ａｂ The composition, [Transmittance measurement 1] A cured product of the composition formed to a thickness of 1 mm is prepared as transmittance measurement sample 1. The transmittance of the transmittance measurement sample 1 at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020) to obtain a transmittance value at a wavelength of 1000 nm. [Color difference measurement 1] A cured product of the composition is formed to a thickness of 1 mm as a color difference measurement sample 1. The color difference measurement sample 1 is placed on a standard white board, and chromaticity measurement is performed. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * (Whiteboard) is obtained respectively. The color difference measurement sample 1 was placed on a standard blackboard, and chromaticity was measured. * a * b * Lightness L in color space * (Blackboard), chromaticity a * (blackboard), chromaticity b * (blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * The value obtained by subtracting (blackboard) is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) is subtracted and the chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As a result, the brightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * respectively. The color difference ΔE is calculated based on the following formula (1): * ａｂ get. [0030]

17. The composition includes a primer composition (1), a composition (2), and a topcoat composition (3), The transmittance at a wavelength of 1000 nm measured by the following transmittance measurement 2 is 30% or more, Color difference ΔE measured by the following color difference measurement 2 * ａｂ is 35 or less. [Transmittance measurement 2] A laminate is obtained as a transmittance measurement sample 2, in which a layer of the primer composition (1) formed to a thickness of 0.1 mm, a layer of the cured product of the composition (2) formed to a thickness of 1 mm, and a layer of the cured product of the topcoat composition (3) formed to a thickness of 0.1 mm are laminated in this order. The transmittance of the transmittance measurement sample 2 at wavelengths from 300 nm to 1500 nm is measured in accordance with JIS K 0115 (2020), and the transmittance value at a wavelength of 1000 nm is obtained. [Color difference measurement 2] As the color difference measurement sample 2, a laminate is obtained in which a layer of the primer composition (1) formed to a thickness of 0.1 mm, a layer of the cured product of the composition (2) formed to a thickness of 1 mm, and a layer of the cured product of the topcoat composition (3) formed to a thickness of 0.1 mm are laminated in this order. The color difference measurement sample 2 is placed on a standard white board, and chromaticity measurement is performed to obtain a value according to CIE1976L. * a * b * Lightness L in color space * (white board), chromaticity a * (white board), chromaticity b * (Whiteboard) is obtained respectively. The color difference measurement sample 2 is placed on a standard blackboard, and the chromaticity is measured. * a * b * Lightness L in color space * (Blackboard), chromaticity a * (blackboard), chromaticity b * (blackboard) is obtained. Then, the brightness L * (Whiteboard) to Lightness L * The value obtained by subtracting (blackboard) is the brightness difference ΔL * , chromaticity a * (White board) to chromaticity a * (Blackboard) is subtracted and the chromaticity difference Δa * , chromaticity b * (White board) to chromaticity b * (Blackboard) is subtracted and the chromaticity difference is Δb * As a result, the brightness difference ΔL * , chromaticity difference Δa * , chromaticity difference Δb * respectively. The color difference ΔE is calculated based on the following formula (1): * ａｂ get. [0045]

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