JP2023149462A - Cross section repairing structure of reinforced concrete structure and cross section repairing method of reinforced concrete structure - Google Patents
Cross section repairing structure of reinforced concrete structure and cross section repairing method of reinforced concrete structure Download PDFInfo
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- 239000011150 reinforced concrete Substances 0.000 title claims abstract description 57
- 238000000034 method Methods 0.000 title claims abstract description 43
- 239000000463 material Substances 0.000 claims abstract description 183
- IDNHOWMYUQKKTI-UHFFFAOYSA-M lithium nitrite Chemical compound [Li+].[O-]N=O IDNHOWMYUQKKTI-UHFFFAOYSA-M 0.000 claims abstract description 57
- 239000004567 concrete Substances 0.000 claims abstract description 48
- 230000002950 deficient Effects 0.000 claims abstract description 9
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 48
- 230000003014 reinforcing effect Effects 0.000 claims description 37
- 230000002265 prevention Effects 0.000 claims description 30
- 230000003449 preventive effect Effects 0.000 claims description 15
- 239000003795 chemical substances by application Substances 0.000 claims description 13
- 239000004570 mortar (masonry) Substances 0.000 claims description 13
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- 238000000576 coating method Methods 0.000 claims description 12
- 238000005507 spraying Methods 0.000 claims description 12
- 239000005038 ethylene vinyl acetate Substances 0.000 claims description 11
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 10
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- 239000004925 Acrylic resin Substances 0.000 claims description 8
- 229920005989 resin Polymers 0.000 claims description 7
- 239000011347 resin Substances 0.000 claims description 7
- DQXBYHZEEUGOBF-UHFFFAOYSA-N but-3-enoic acid;ethene Chemical compound C=C.OC(=O)CC=C DQXBYHZEEUGOBF-UHFFFAOYSA-N 0.000 claims description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 4
- 238000010030 laminating Methods 0.000 claims description 4
- 229910052744 lithium Inorganic materials 0.000 claims description 4
- 239000010410 layer Substances 0.000 abstract description 55
- 230000000694 effects Effects 0.000 abstract description 19
- 239000000853 adhesive Substances 0.000 abstract description 4
- 230000001070 adhesive effect Effects 0.000 abstract description 4
- 239000002344 surface layer Substances 0.000 abstract description 3
- 239000013556 antirust agent Substances 0.000 abstract 1
- 239000004568 cement Substances 0.000 description 17
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 13
- 239000011433 polymer cement mortar Substances 0.000 description 11
- 238000011156 evaluation Methods 0.000 description 8
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- 229920000642 polymer Polymers 0.000 description 7
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 6
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- 229920001577 copolymer Polymers 0.000 description 5
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- 150000003839 salts Chemical class 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 4
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 4
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 3
- 239000011398 Portland cement Substances 0.000 description 3
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 238000009415 formwork Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 229920002978 Vinylon Polymers 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000010881 fly ash Substances 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 2
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- 229920000609 methyl cellulose Polymers 0.000 description 2
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- 239000010959 steel Substances 0.000 description 2
- 239000002562 thickening agent Substances 0.000 description 2
- OEPOKWHJYJXUGD-UHFFFAOYSA-N 2-(3-phenylmethoxyphenyl)-1,3-thiazole-4-carbaldehyde Chemical compound O=CC1=CSC(C=2C=C(OCC=3C=CC=CC=3)C=CC=2)=N1 OEPOKWHJYJXUGD-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 244000043261 Hevea brasiliensis Species 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-M Methacrylate Chemical compound CC(=C)C([O-])=O CERQOIWHTDAKMF-UHFFFAOYSA-M 0.000 description 1
- NWBJYWHLCVSVIJ-UHFFFAOYSA-N N-benzyladenine Chemical compound N=1C=NC=2NC=NC=2C=1NCC1=CC=CC=C1 NWBJYWHLCVSVIJ-UHFFFAOYSA-N 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-N Nitrous acid Chemical compound ON=O IOVCWXUNBOPUCH-UHFFFAOYSA-N 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 1
- 150000008360 acrylonitriles Chemical class 0.000 description 1
- 229910001413 alkali metal ion Inorganic materials 0.000 description 1
- 239000002518 antifoaming agent Substances 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000011400 blast furnace cement Substances 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 239000002734 clay mineral Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000004499 emulsifiable powder Substances 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
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- 239000004615 ingredient Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- 229940005654 nitrite ion Drugs 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229920001084 poly(chloroprene) Polymers 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 229920005862 polyol Polymers 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
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- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Landscapes
- Working Measures On Existing Buildindgs (AREA)
- Bridges Or Land Bridges (AREA)
- Aftertreatments Of Artificial And Natural Stones (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
Description
本発明は、鉄筋コンクリート構造物の断面修復構造および鉄筋コンクリート構造物の断面修復方法に関する。 The present invention relates to a cross-sectional repair structure for a reinforced concrete structure and a cross-sectional repair method for a reinforced concrete structure.
近年、既設の鉄筋コンクリート構造物において、海岸部で飛来する空気中の塩分や凍結防止剤などの塩分がコンクリート表面から内部へ浸透して鉄筋を腐食させる塩害が問題となっている。塩害による鉄筋腐食が発生した既設鉄筋コンクリート構造物に対して、塩分（塩化物イオン）濃度が高くなっているコンクリート部分を除去し、補修材料を用いて修復し、鉄筋の更なる腐食を防止する断面修復工法が一般に行われている。 In recent years, salt damage has become a problem in existing reinforced concrete structures, where salt in the air or salt from anti-freezing agents, etc., blown from the coast permeates from the concrete surface into the interior and corrodes the reinforcing bars. A cross-section of an existing reinforced concrete structure where corrosion of reinforcing bars due to salt damage occurred, where the concrete parts with high concentrations of salt (chloride ions) were removed and repaired using repair materials to prevent further corrosion of the reinforcing bars. Restoration methods are commonly used.
この既設の鉄筋コンクリート構造物の断面修復工法については、種々の工法が提案されており、例えば、鉄筋腐食が発生している部位からコンクリートをはつり取って除去し、構造物内部に完全に埋設されている鉄筋を露出させ、その鉄筋の表面に亜硝酸リチウムに代表される亜硝酸系防錆剤などを塗布した後、コンクリートがはつり取られた欠損凹部に断面修復用の補修材料を充填して修復する方法が挙げられる。
例えば、引用文献１には、コンクリート構造物の修復部分のコンクリートをはつり取った後、はつり取られた部分と断面修復モルタルとの接着界面、及び露出した鉄筋表面の全面に、亜硝酸塩水溶液を塗布し、次いで、ポリマーセメントモルタルを塗布した後、断面修復モルタルを用いて断面修復することを特徴とする塩害劣化コンクリートの補修方法が開示されている。
Various methods have been proposed for cross-sectional repair of existing reinforced concrete structures. For example, concrete is removed from areas where reinforcement corrosion has occurred, and the concrete is completely buried inside the structure. After exposing the reinforced reinforcing bars and applying a nitrite-based rust preventive agent such as lithium nitrite to the surface of the reinforcing bars, the damaged recess where the concrete has been removed is filled with a repair material to repair the cross section. One method is to do so.
For example, in Cited Document 1, after removing the concrete from the repaired part of a concrete structure, a nitrite aqueous solution is applied to the adhesive interface between the removed part and the cross-section repair mortar, and to the entire surface of the exposed reinforcing bars. A method for repairing salt-damaged concrete is disclosed, which comprises applying a polymer cement mortar and then repairing the cross section using a cross-section repair mortar.
ところで、亜硝酸リチウムを混合した断面修復材はコストがかかるため、鉄筋の近傍にのみ、亜硝酸リチウムを混合した断面修復材が用いられ、表層部分は亜硝酸リチウムを混合しない断面修復材を用いることが一般に行われている。
しかしながら、亜硝酸リチウムは保水性を持つことから、亜硝酸リチウムを混合した断面修復材と、亜硝酸リチウムを混合しない断面修復材との界面で水分が移動し、界面の付着力に影響することが確認された。
そこで本発明は、防錆効果の高い亜硝酸リチウムを混合した断面修復材と、亜硝酸リチウムを混合しない断面修復材の界面の付着力をさらに向上させた、鉄筋コンクリート構造物の断面修復構造、および鉄筋コンクリート構造物の断面修復方法を提供することを課題とする。
By the way, cross-section repair material mixed with lithium nitrite is expensive, so cross-section repair material mixed with lithium nitrite is used only near reinforcing bars, and cross-section repair material without lithium nitrite is used on the surface layer. This is commonly done.
However, since lithium nitrite has water-retentive properties, water may move at the interface between the cross-sectional repair material mixed with lithium nitrite and the cross-sectional repair material mixed with lithium nitrite, which may affect the adhesion force at the interface. was confirmed.
Therefore, the present invention provides a cross-sectional repair structure for reinforced concrete structures, which further improves the adhesion of the interface between a cross-sectional repair material mixed with lithium nitrite, which has a high rust prevention effect, and a cross-sectional repair material not mixed with lithium nitrite, and The objective is to provide a method for cross-sectional repair of reinforced concrete structures.
上記課題を解決するために鋭意検討したところ、本発明者らは下記本発明に想到し、当該課題を解決できることを見出した。すなわち本発明は下記のとおりである。 As a result of intensive studies to solve the above problem, the present inventors came up with the following invention and found that the problem could be solved. That is, the present invention is as follows.
［１］既設鉄筋コンクリート構造物の欠陥部における表層コンクリートを鉄筋の少なくとも一部が露出するまで除去して形成されるコンクリート除去部と、露出した鉄筋の周囲を覆う防錆剤として亜硝酸リチウムを含む断面修復材Ａ、及び該断面修復材Ａにプライマー層を介して積層される亜硝酸リチウム非含有断面修復材Ｂを含む補修材とを有し、該補修材が前記コンクリート除去部に充填されてなる鉄筋コンクリート構造物の断面修復構造。
［２］前記プライマー層が、アクリル系樹脂又はエチレン－酢酸ビニル系樹脂を含有する上記［１］に記載の鉄筋コンクリート構造物の断面修復構造。
［３］前記断面修復材Ａの厚みが５～５０ｍｍである上記［１］又は［２］に記載の鉄筋コンクリート構造物の断面修復構造。
［４］前記プライマー層を形成するためのプライマー層形成材料の不揮発分の塗布量が、５～５０ｇ／ｍ２である上記［１］～［３］のいずれかに記載の鉄筋コンクリート構造物の断面修復構造。
［５］前記鉄筋と前記断面修復材Ａの間に防錆層をさらに有する上記［１］～［４］のいずれかに記載の鉄筋コンクリート構造物の断面修復構造。
［６］前記防錆層が亜硝酸リチウムを含有する上記［５］に記載の鉄筋コンクリート構造物の断面修復構造。
［７］前記防錆層の塗布量が３００～５０００ｋｇ／ｍ２である上記［５］又は［６］に記載の鉄筋コンクリート構造物の断面修復構造。
［８］前記断面修復材Ａ及び断面修復材Ｂの主成分がモルタル組成物である上記［１］～［７］のいずれかに記載の鉄筋コンクリート構造物の断面修復構造。
［９］既設鉄筋コンクリート構造物の欠陥部における表層コンクリートを鉄筋の少なくとも一部が露出するまで除去する工程（Ｉ）、露出した鉄筋の周囲を防錆剤として亜硝酸リチウムを含有する断面修復材Ａで覆う工程（II）、該断面修復材Ａの表面にプライマー層形成材料を塗布し、プライマー層を形成する工程（III）、該プライマー層上に亜硝酸リチウム非含有の断面修復材Ｂを積層する工程（IV）を有する、鉄筋コンクリート構造物の断面修復方法。
［１０］前記プライマー層形成材料がアクリル系樹脂又はエチレン－酢酸ビニル系樹脂を含有する上記［９］に記載の鉄筋コンクリート構造物の断面修復方法。
［１１］プライマー層形成材料の不揮発分の塗布量が、５～５０ｇ／ｍ２である上記［９］または［１０］に記載の鉄筋コンクリート構造物の断面修復方法。
［１２］前記工程（ＩＩ）の後、前記工程（III）の開始前に、３時間以上の保持時間を有する上記［９］～［１１］のいずれかに記載の鉄筋コンクリート構造物の断面修復方法。
［１３］前記断面修復材Ｂが吹付法により積層される上記［９］～［１２］のいずれかに記載の鉄筋コンクリート構造物の断面修復方法。
［１４］前記工程（Ｉ）の後、前記工程（ＩＩ）の前に鉄筋に防錆剤を塗布して、防錆層を形成する工程を有する上記［９］～［１３］のいずれかに記載の鉄筋コンクリート構造物の断面修復方法。
[1] Contains lithium nitrite as a rust preventive agent that covers the concrete removed part formed by removing the surface concrete in the defective part of the existing reinforced concrete structure until at least a part of the reinforcing bars are exposed, and the area around the exposed reinforcing bars. A cross-section repair material A, and a repair material including a lithium nitrite-free cross-section repair material B laminated on the cross-section repair material A via a primer layer, and the repair material is filled in the concrete removal part. A cross-sectional repair structure of a reinforced concrete structure.
[2] The cross-sectional repair structure of a reinforced concrete structure according to [1] above, wherein the primer layer contains an acrylic resin or an ethylene-vinyl acetate resin.
[3] The cross-sectional repair structure for a reinforced concrete structure according to [1] or [2] above, wherein the cross-sectional repair material A has a thickness of 5 to 50 mm.
[4] The cross section of the reinforced concrete structure according to any one of [1] to [3] above, wherein the coating amount of the non-volatile content of the primer layer forming material for forming the primer layer is 5 to 50 g/ m2 . repair structure.
[5] The cross-sectional repair structure for a reinforced concrete structure according to any one of [1] to [4] above, further comprising a rust prevention layer between the reinforcing bars and the cross-sectional repair material A.
[6] The cross-sectional repair structure of a reinforced concrete structure according to [5] above, wherein the rust prevention layer contains lithium nitrite.
[7] The cross-sectional repair structure for a reinforced concrete structure according to [5] or [6] above, wherein the amount of the anticorrosive layer applied is 300 to 5000 kg/m 2 .
[8] The cross-sectional repair structure for a reinforced concrete structure according to any one of [1] to [7] above, wherein the main component of the cross-section repair material A and the cross-section repair material B is a mortar composition.
[9] Step (I) of removing the surface concrete in the defective part of the existing reinforced concrete structure until at least a part of the reinforcing bars are exposed, cross-sectional repair material A containing lithium nitrite as a rust preventive agent around the exposed reinforcing bars step (II) of coating the surface of the cross-section repair material A with a primer layer forming material to form a primer layer (III), laminating the cross-section repair material B that does not contain lithium nitrite on the primer layer. A method for cross-sectional repair of a reinforced concrete structure, comprising step (IV) of
[10] The method for cross-sectional repair of a reinforced concrete structure according to [9] above, wherein the primer layer forming material contains an acrylic resin or an ethylene-vinyl acetate resin.
[11] The method for cross-sectional repair of a reinforced concrete structure according to [9] or [10] above, wherein the coating amount of the non-volatile content of the primer layer forming material is 5 to 50 g/m 2 .
[12] The method for cross-sectional repair of a reinforced concrete structure according to any one of [9] to [11] above, which has a holding time of 3 hours or more after the step (II) and before the start of the step (III). .
[13] The cross-section repair method for a reinforced concrete structure according to any one of [9] to [12] above, wherein the cross-section repair material B is laminated by a spraying method.
[14] Any one of the above [9] to [13], which has a step of applying a rust preventive agent to the reinforcing steel to form a rust preventive layer after the step (I) and before the step (II). Cross-section repair method for reinforced concrete structures described.
本発明によれば、亜硝酸リチウムを混合した断面修復材と、亜硝酸リチウムを混合しない断面修復材の界面の付着力を向上させた、鉄筋コンクリート構造物の断面修復構造、および鉄筋コンクリート構造物の断面修復方法を提供することができる。 According to the present invention, there is provided a cross-section repair structure for a reinforced concrete structure, and a cross-section repair structure for a reinforced concrete structure, in which the adhesion of the interface between a cross-section repair material mixed with lithium nitrite and a cross-section repair material not mixed with lithium nitrite is improved. A repair method can be provided.
［鉄筋コンクリート構造物の断面修復構造］
本発明の鉄筋コンクリート構造物の断面修復構造（以下、「本発明の断面修復構造」と記載することがある。）は、既設鉄筋コンクリート構造物の欠陥部における表層コンクリートを鉄筋の少なくとも一部が露出するまで除去して形成されるコンクリート除去部と、露出した鉄筋の周囲を覆う防錆剤として亜硝酸リチウムを含む断面修復材Ａ、及び該断面修復材Ａにプライマー層を介して積層される亜硝酸リチウム非含有断面修復材Ｂを含む補修材とを有し、該補修材が前記コンクリート除去部に充填されてなる。
[Cross-sectional repair structure of reinforced concrete structure]
The cross-sectional repair structure for a reinforced concrete structure of the present invention (hereinafter sometimes referred to as the "cross-sectional repair structure of the present invention") is a structure in which at least a portion of reinforcing bars are exposed in the surface concrete at a defective part of an existing reinforced concrete structure. A section repair material A containing lithium nitrite as a rust preventive agent that covers the concrete removed part formed by removing up to and a repair material containing a lithium-free cross-section repair material B, and the repair material is filled in the concrete removal section.
以下、本発明の鉄筋コンクリート構造物の断面修復構造について、図１を参照しつつ詳細に説明する。
＜コンクリート除去部＞
既設鉄筋コンクリート構造物は、コンクリート３０の内部に鉄製の鉄筋２０が埋設された構造を有する。鉄筋２０からコンクリート外表面までが所定の厚みの表層コンクリート３２によって被覆されている。コンクリート除去部は、既設鉄筋コンクリート構造物の欠陥部における表層コンクリート３２をはつり取って、既設鉄筋コンクリート構造物の外表面を部分的に欠損させた部位である。ここで、欠陥部とは、塩化物イオン濃度が高く、コンクリート内部の鉄筋の腐食が認められるか、または鉄筋の腐食が予測される箇所のことをいう。
上記コンクリート除去部には、以下に詳述する補修材１０が未硬化の状態で充填され、硬化され、コンクリート除去部であった箇所が補修材１０によって復元される。
Hereinafter, the cross-sectional repair structure of a reinforced concrete structure according to the present invention will be described in detail with reference to FIG. 1.
<Concrete removal section>
The existing reinforced concrete structure has a structure in which iron reinforcing bars 20 are buried inside concrete 30. The area from the reinforcing bars 20 to the outer surface of the concrete is covered with a surface concrete layer 32 having a predetermined thickness. The concrete removal part is a part where the outer surface of the existing reinforced concrete structure is partially damaged by removing the surface layer concrete 32 at the defective part of the existing reinforced concrete structure. Here, the defective portion refers to a location where the concentration of chloride ions is high and corrosion of the reinforcing bars inside the concrete is observed or where corrosion of the reinforcing bars is predicted.
The concrete removed portion is filled with a repair material 10, which will be described in detail below, in an uncured state and cured, and the portion that was the concrete removed portion is restored by the repair material 10.
＜補修材＞
補修材１０は、亜硝酸リチウムを含む断面修復材Ａ（以下、「断面修復材Ａ」と記載することがある。図１中の１１）、亜硝酸リチウム非含有断面修復材Ｂ（以下、「断面修復材Ｂ」と記載することがある。図１中の１２）、及びプライマー層１３を有する。
<Repair materials>
The repair material 10 includes cross-section repair material A containing lithium nitrite (hereinafter sometimes referred to as "cross-section repair material A". 11 in FIG. 1), cross-section repair material B not containing lithium nitrite (hereinafter "cross-section repair material A"). 12) in FIG. 1 and a primer layer 13.
（亜硝酸リチウム含有断面修復材Ａ）
亜硝酸リチウム含有断面修復材Ａ（図１中の１１）は、修復材中に亜硝酸リチウムを含有することが特徴である。断面修復材Ａを構成する主な材料としては、例えば、ポリマーセメントモルタルを含むモルタル組成物が挙げられ、断面修復材Ａはモルタル組成物および亜硝酸リチウムを含有するものが好適に用いられる。
ポリマーセメントモルタルの種類については特に制限はなく、各種のポリマーセメントモルタルを使用することができる。ポリマーセメントモルタルは、セメントにセメント混和用ポリマーを加えたものであり、該ポリマーの含有量はセメント１００質量部に対して、１～３０質量部であることが好ましい。ポリマーの含有量が１質量部以上であると、鉄筋の腐食物質である塩化物イオンがコンクリート３０から鉄筋２０へ移動することを抑制することができる。一方、３０質量部以下であると、相対的にセメントの含有量が多くなり、鉄筋との付着性が良好となる。以上の観点から、ポリマーの含有量は、２～１５質量部であることがより好ましく、３～１０質量部であることがさらに好ましい。
(Cross-section repair material containing lithium nitrite A)
The lithium nitrite-containing cross-sectional repair material A (11 in FIG. 1) is characterized by containing lithium nitrite in the repair material. The main materials constituting the cross-section repair material A include, for example, a mortar composition containing polymer cement mortar, and the cross-section repair material A preferably contains a mortar composition and lithium nitrite.
There is no particular restriction on the type of polymer cement mortar, and various polymer cement mortars can be used. Polymer cement mortar is made by adding a cement-mixing polymer to cement, and the content of the polymer is preferably 1 to 30 parts by mass based on 100 parts by mass of cement. When the content of the polymer is 1 part by mass or more, chloride ions, which are corrosive substances for reinforcing bars, can be prevented from moving from concrete 30 to reinforcing bars 20. On the other hand, if it is 30 parts by mass or less, the cement content will be relatively large and the adhesion to reinforcing bars will be good. From the above viewpoint, the content of the polymer is more preferably 2 to 15 parts by weight, and even more preferably 3 to 10 parts by weight.
モルタル組成物に用いるセメントとしては、特に制限されるものではなく、例えば、ポルトランドセメント（普通、早強、超早強、耐硫酸塩、中庸熱、低熱）、混合セメント（高炉セメント、フライアッシュセメント、シリカセメント）、白色ポルトランドセメント、微粉セメントなどを使用することができる。またセメント用混和材として、高炉スラグ微粉末、フライアッシュ、シリカヒューム、石灰石粉等を使用してもよいし、さらに、必要に応じて、カルシウムスルホアルミネート（ＣＳＡ）系等の膨張材等を添加してもよい。
セメント混和用ポリマーとしては、特に限定されるものではないが、アクリロニトリル・ブタジエンゴム、スチレン・ブタジエンゴム、クロロプレンゴム、天然ゴム等のゴムラテックスや、エチレン・酢酸ビニル共重合体、ポリアクリル酸エステル、スチレン・アクリル酸エステル共重合体やアクリロニトリル・アクリル酸エステルに代表されるアクリル酸エステル系共重合体、酢酸ビニルビニルバーサテート系共重合体等の樹脂エマルジョン等が挙げられる。
ポリマーの形態としては、再乳化型粉末タイプや液体タイプがあり、下地部分との付着性改善、さらに、モルタルの耐久性向上のために使用できる。
The cement used in the mortar composition is not particularly limited, and includes, for example, Portland cement (normal, early strength, super early strength, sulfate resistant, moderate heat, low heat), mixed cement (blast furnace cement, fly ash cement). , silica cement), white Portland cement, fine powder cement, etc. can be used. Further, as an admixture for cement, powdered blast furnace slag, fly ash, silica fume, limestone powder, etc. may be used, and if necessary, an expansive material such as calcium sulfoaluminate (CSA) may be used. May be added.
Polymers for cement admixture include, but are not particularly limited to, rubber latex such as acrylonitrile-butadiene rubber, styrene-butadiene rubber, chloroprene rubber, natural rubber, ethylene-vinyl acetate copolymer, polyacrylic ester, Examples include resin emulsions such as styrene/acrylic ester copolymers, acrylic ester copolymers typified by acrylonitrile/acrylic esters, and vinyl acetate vinyl versatate copolymers.
The form of the polymer includes a re-emulsifiable powder type and a liquid type, and can be used to improve adhesion to the base and also to improve the durability of mortar.
また、モルタル組成物に添加し得るその他成分としては、石灰砂、珪砂などの砂、膨張材、促進材、急硬材、ポリプロピレンファイバー、ビニロンファイバーなどのファイバー、ポリオール系等の収縮低減剤、メチルセルロースや粘土鉱物等の増粘剤、減水剤、消泡剤等が挙げられる。
砂に関しては、セメント１００質量部に対して、５０～３００質量部の範囲であることが好ましい。当該範囲であると断面修復材Ａの強度が十分なものとなる。以上の点から、砂の含有量は、セメント１００質量部に対して、８０～２５０質量部の範囲であることがさらに好ましい。
また、その他の成分に関しては、必要に応じて添加すればよく、セメント１００質量部に対して、０．０１～２０質量部の範囲で添加することができる。
Other ingredients that can be added to the mortar composition include sand such as lime sand and silica sand, expanding agents, accelerators, rapid hardening materials, fibers such as polypropylene fiber and vinylon fiber, shrinkage reducing agents such as polyols, and methyl cellulose. Examples include thickeners such as clay minerals, water reducing agents, and antifoaming agents.
Regarding sand, it is preferably in the range of 50 to 300 parts by mass based on 100 parts by mass of cement. Within this range, the strength of the cross-sectional repair material A will be sufficient. In view of the above, it is more preferable that the content of sand is in the range of 80 to 250 parts by mass based on 100 parts by mass of cement.
Further, other components may be added as necessary, and can be added in the range of 0.01 to 20 parts by mass based on 100 parts by mass of cement.
＜モルタル組成物の作製方法＞
モルタル組成物は、上述のセメント、砂、その他の成分を所定の配合で混合することで作製できる。
混合装置としては、既存の如何なる装置も使用可能であり、例えば、傾胴ミキサー，オムニミキサー，プロシェアミキサー，ヘンシェルミキサー，Ｖ型ミキサー及びナウターミキサー等が挙げられる。
<Method for producing mortar composition>
The mortar composition can be prepared by mixing the above-mentioned cement, sand, and other components in a predetermined composition.
As the mixing device, any existing device can be used, and examples thereof include a tilting mixer, an omni mixer, a Proshear mixer, a Henschel mixer, a V-type mixer, and a Nauta mixer.
断面修復材Ａの厚みとしては、本発明の効果を奏する範囲であれば特に限定されないが、５～５０ｍｍの範囲であることが好ましい。断面修復材Ａの厚みが５ｍｍ以上であると、塩化物イオンに対する優れた遮断効果が発揮され、５０ｍｍ以下であるとコスト的なメリットがある。以上の観点から、断面修復材Ａの厚みは５～５０ｍｍの範囲であることがさらに好ましい。 The thickness of the cross-sectional repair material A is not particularly limited as long as it achieves the effects of the present invention, but it is preferably in the range of 5 to 50 mm. When the thickness of the cross-section repair material A is 5 mm or more, an excellent blocking effect against chloride ions is exhibited, and when it is 50 mm or less, there is a cost advantage. From the above viewpoint, it is more preferable that the thickness of the cross-sectional repair material A is in the range of 5 to 50 mm.
本発明では、防錆剤として亜硝酸リチウムを用いる。亜硝酸リチウムは、水溶性防錆材であり、断面修復材Ａの主成分であるモルタルに混合されて使用される。また、亜硝酸リチウムは、防錆性能が高く、鉄筋の表面に不動態被膜を形成するイオン成分を有し、アルカリ性を高めるアルカリ金属イオンを有することから、特に好ましい。コンクリートのアルカリシリカ反応を抑制する効果も付与することができる。
なお、亜硝酸リチウムは、コンクリート除去部に充填される前の未硬化状態の断面修復材Ａにあらかじめ混合されていることが好ましい。
断面修復材Ａは、図１に示されるように、露出した鉄筋２０の周囲を覆うように配され、鉄筋２０に対して、防錆性能を発揮する。
In the present invention, lithium nitrite is used as a rust preventive agent. Lithium nitrite is a water-soluble rust preventive material, and is used by being mixed with mortar, which is the main component of the cross-section repair material A. Moreover, lithium nitrite is particularly preferable because it has high rust prevention performance, has an ionic component that forms a passive film on the surface of reinforcing bars, and has alkali metal ions that increase alkalinity. It can also have the effect of suppressing the alkali-silica reaction in concrete.
Note that lithium nitrite is preferably mixed in advance with the uncured cross-section repair material A before it is filled into the concrete removal section.
As shown in FIG. 1, the cross-section repair material A is disposed to cover the exposed reinforcing bars 20, and exhibits rust prevention performance for the reinforcing bars 20.
断面修復材Ａ中の亜硝酸リチウムの固形分の含有量は、本発明の効果を奏する範囲であれば特に限定されないが、主成分であるポリマーセメントモルタル１００質量部に対して、０．５～３０質量部であることが好ましい。亜硝酸リチウムが０．５質量部以上であると、十分な防錆効果が得られ、３０質量部以下であれば、相対的にポリマーセメントモルタルの含有量が多くなり、断面修復材の十分な強度が得られる。以上の観点から、亜硝酸リチウムの固形分の含有量は、１～１５質量部であることがさらに好ましい。 The solid content of lithium nitrite in the cross-sectional repair material A is not particularly limited as long as it achieves the effects of the present invention, but it ranges from 0.5 to 100 parts by mass of polymer cement mortar, which is the main component. Preferably, it is 30 parts by mass. When lithium nitrite is 0.5 parts by mass or more, a sufficient rust prevention effect can be obtained, and when it is 30 parts by mass or less, the content of polymer cement mortar becomes relatively large, and the content of the cross-section repair material becomes insufficient. Provides strength. From the above viewpoint, it is more preferable that the solid content of lithium nitrite is 1 to 15 parts by mass.
（亜硝酸リチウム非含有断面修復材Ｂ）
亜硝酸リチウム非含有断面修復材Ｂ（図１中の１２）は、後に詳述するプライマー層１３を介して、前記亜硝酸リチウム含有断面修復材Ａに積層される。断面修復材Ｂは硝酸リチウムを含有しないことが特徴である。このような態様をとることで、亜硝酸リチウムの使用量を減らすことができ、かつ少ない亜硝酸リチウムの使用量で、鉄筋に対して十分な防錆効果を付与することができる。
断面修復材Ｂを構成する材料としては、亜硝酸リチウムを含まない点を除いて、断面修復材Ａと同様の材料を用いることが好ましい。断面修復材Ａと同様のモルタル組成物を主成分とすることで、断面修復材Ａとの密着性が向上し、断面修復材Ａと断面修復材Ｂの界面の付着力が向上する。
(Cross-section repair material B that does not contain lithium nitrite)
The lithium nitrite-free cross-section repair material B (12 in FIG. 1) is laminated on the lithium nitrite-containing cross-section repair material A via a primer layer 13, which will be described in detail later. Cross-section repair material B is characterized in that it does not contain lithium nitrate. By adopting such an aspect, the amount of lithium nitrite used can be reduced, and a sufficient rust prevention effect can be imparted to the reinforcing steel with a small amount of lithium nitrite used.
As the material constituting the cross-section repair material B, it is preferable to use the same material as the cross-section repair material A, except that it does not contain lithium nitrite. By using the same mortar composition as the cross-section repair material A as the main component, the adhesion with the cross-section repair material A is improved, and the adhesion force at the interface between the cross-section repair material A and the cross-section repair material B is improved.
（プライマー層）
本発明の断面修復構造は、断面修復材Ａにプライマー層を介して断面修復材Ｂが積層されることが特徴である。断面修復材Ａと断面修復材Ｂの間にプライマー層を有することで、断面修復材Ａと断面修復材Ｂの密着性が向上し、断面修復材Ａと断面修復材Ｂの界面の付着力が向上する。
また、プライマー層により、亜硝酸イオンがコンクリート表面３１に向けて拡散することがなく、鉄筋２０に対する防錆効果が長時間にわたって維持される。
(Primer layer)
The cross-section repair structure of the present invention is characterized in that the cross-section repair material B is laminated on the cross-section repair material A with a primer layer interposed therebetween. By having a primer layer between the cross-section repair material A and the cross-section repair material B, the adhesion between the cross-section repair material A and the cross-section repair material B is improved, and the adhesion force at the interface between the cross-section repair material A and the cross-section repair material B is improved. improves.
Further, the primer layer prevents nitrite ions from diffusing toward the concrete surface 31, and the rust prevention effect on the reinforcing bars 20 is maintained for a long time.
プライマー層を構成する材料としては、本発明の効果を奏する範囲であれば、特に限定されないが、上記効果を奏するものとして、アクリル系樹脂又はエチレン－酢酸ビニル系樹脂（以下「ＥＶＡ」と記載する。）が好適に挙げられる。アクリル系樹脂又はＥＶＡを用いることで、断面修復材Ａと断面修復材Ｂの密着性が向上し、亜硝酸イオンの拡散も抑制される。
アクリル系樹脂としては、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ブチル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレートなどの（メタ）アクリレート化合物を１種または２種以上重合したもの、さらにこれらのモノマーと共重合可能なスチレン、酢酸ビニル、塩化ビニリデンなどのビニル化合物と共重合させたもの等を用いることができる。なお、（メタ）アクリレートとは、メタクリレート及びアクリレートを意味する。
ＥＶＡとしては、エチレンと酢酸ビニルとを公知の方法で共重合したものであればよく、該共重合体中の酢酸ビニル含有量は、好ましくは２０～９０質量％、さらに好ましくは３０～９０質量％である。
The material constituting the primer layer is not particularly limited as long as it achieves the effects of the present invention, but examples of materials that achieve the above effects include acrylic resins or ethylene-vinyl acetate resins (hereinafter referred to as "EVA"). ) are preferably mentioned. By using the acrylic resin or EVA, the adhesion between the cross-section repair material A and the cross-section repair material B is improved, and the diffusion of nitrite ions is also suppressed.
Acrylic resins include those obtained by polymerizing one or more (meth)acrylate compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; Those copolymerized with vinyl compounds such as styrene, vinyl acetate, and vinylidene chloride that can be copolymerized with these monomers can be used. Note that (meth)acrylate means methacrylate and acrylate.
EVA may be one obtained by copolymerizing ethylene and vinyl acetate by a known method, and the vinyl acetate content in the copolymer is preferably 20 to 90% by mass, more preferably 30 to 90% by mass. %.
プライマー層の厚みとしては、上記効果を奏する範囲であれば特に限定されないが、プライマー層を形成するためのプライマー層形成材料の不揮発分の塗布量として、５～５０ｇ／ｍ２であることが好ましい。プライマー層の厚みがこの範囲内であると、断面修復材Ａと断面修復材Ｂの密着性が十分となり、かつ亜硝酸イオンの表面コンクリート方向への拡散も抑制される。以上の観点から、プライマー層の不揮発分の塗布量は、１０ｇ／ｍ２～４０ｇ／ｍ２の範囲であることがさらに好ましい。 The thickness of the primer layer is not particularly limited as long as it achieves the above effects, but it is preferably 5 to 50 g/m 2 as the coating amount of non-volatile content of the primer layer forming material for forming the primer layer. . When the thickness of the primer layer is within this range, the adhesion between the cross-section repair material A and the cross-section repair material B will be sufficient, and diffusion of nitrite ions toward the surface concrete will also be suppressed. From the above viewpoint, it is more preferable that the coating amount of nonvolatile components of the primer layer is in the range of 10 g/m 2 to 40 g/m 2 .
（防錆層）
本発明の断面修復構造は、鉄筋と上記断面修復材Ａの間に防錆層をさらに有することが好ましい。防錆層を有することで、さらに鉄筋の防錆性を向上させることができる。防錆層に用いる材料としては、防錆効果のあるものであれば、特に制限はないが、断面修復材Ａに用いられる亜硝酸リチウムを含有することが好ましい。亜硝酸リチウムは、上述のように優れた防錆効果を有し、かつ、アルカリ性を高める点からも好ましい。
亜硝酸リチウムはセメントと混合しセメントペーストとして、鉄筋に塗布することが好ましい。亜硝酸水溶液の濃度については、特に限定はないが、通常、１０～５０質量％程度の濃度の水溶液として用いればよい。
防錆層の塗布量としては、上記効果を効率的に得るとの観点から、固形分換算で、３００～５０００ｋｇ／ｍ２であることが好ましく、５００～４０００ｋｇ／ｍ２の範囲であることがさらに好ましい。この範囲であると防錆効果がより得られやすい。
防錆層の形成方法としては、本発明の効果を奏する範囲であれば、特に限定されず、亜硝酸リチウムペーストを鉄筋に吹き付ける方法や、コテ、ヘラ、刷毛、又はローラー等で塗布する方法が挙げられる。
(rust prevention layer)
It is preferable that the cross-sectional repair structure of the present invention further includes a rust prevention layer between the reinforcing bars and the cross-sectional repair material A. By having the rust prevention layer, the rust prevention properties of the reinforcing bars can be further improved. The material used for the rust prevention layer is not particularly limited as long as it has a rust prevention effect, but preferably contains lithium nitrite, which is used in the cross-section repair material A. Lithium nitrite is preferable because it has an excellent antirust effect as described above and also improves alkalinity.
It is preferable that lithium nitrite be mixed with cement and applied to the reinforcing bars as a cement paste. There are no particular limitations on the concentration of the nitrous acid aqueous solution, but it may normally be used as an aqueous solution having a concentration of about 10 to 50% by mass.
From the viewpoint of efficiently obtaining the above effects, the coating amount of the rust prevention layer is preferably 300 to 5000 kg/m 2 in terms of solid content, and preferably in the range of 500 to 4000 kg/m 2 . More preferred. Within this range, the rust prevention effect is more likely to be obtained.
The method of forming the rust prevention layer is not particularly limited as long as it achieves the effects of the present invention, and methods include spraying lithium nitrite paste onto the reinforcing bars, and applying it with a trowel, spatula, brush, or roller. Can be mentioned.
＜充填方法＞
上記補修材をコンクリート除去部に充填する方法については、特に制限はなく、既存の種々の方法が適用可能である。例えば、未硬化状態の補修材をコンクリート除去部へ吹き付ける工法（吹き付け工法）や、未硬化状態の補修材をコンクリート除去部へコテで押さえる工法（左官工法）や、コンクリート除去部の外側にコンクリート型枠を設置して、コンクリート除去部とコンクリート型枠との間に未硬化状態の補修材を注入して、コンクリート除去部へ充填して硬化させる工法（グラウト工法）を用いることができる。
本発明では、施工の効率の点から、吹き付け工法が好ましい。具体的には、亜硝酸リチウム含有断面修復材を吹き付け施工し、硬化させた後にプライマー層形成材料を吹き付け塗工または刷毛塗りし、乾燥してプライマー層を形成した後に、亜硝酸リチウム非含有断面修復材を吹き付け施工する方法が好ましい。
<Filling method>
There is no particular restriction on the method of filling the repair material into the concrete removed portion, and various existing methods can be applied. For example, there is a method in which uncured repair material is sprayed onto the concrete removed area (spraying method), an uncured repair material is pressed onto the concrete removed area with a trowel (plastering method), and a concrete mold is placed on the outside of the concrete removed area. A method (grout method) can be used in which a frame is installed, an uncured repair material is injected between the concrete removed part and the concrete formwork, and the repair material is filled into the concrete removed part and hardened.
In the present invention, the spraying method is preferred from the viewpoint of construction efficiency. Specifically, a lithium nitrite-containing cross-section repair material is sprayed, cured, and then a primer layer-forming material is spray-coated or brush-coated, dried to form a primer layer, and then a lithium-nitrite-free cross-section repair material is applied. A method of spraying the repair material is preferred.
［鉄筋コンクリート構造物の断面修復方法］
本発明の鉄筋コンクリート構造物の断面修復方法（以下、「本断面修復方法」と記載することがある。）は、以下の４つの工程を含む。
（Ｉ）既設鉄筋コンクリート構造物の欠陥部における表層コンクリートを鉄筋の少なくとも一部が露出するまで除去する工程。
（II）露出した鉄筋の周囲を防錆剤として亜硝酸リチウムを含有する断面修復材Ａで覆う工程。
（III）該断面修復材Ａの表面にプライマー層形成材料を塗布し、プライマー層を形成する工程。
（IV）該プライマー層上に亜硝酸リチウム非含有の断面修復材Ｂを積層する工程。
上記工程（II）における断面修復材Ａで鉄筋の周囲を覆う工程、上記工程（III）におけるプライマー層形成材料を塗布する工程、及び工程（IV）における断面修復材Ｂを積層する工程は、既存のいかなる方法でもよい。具体的には、はけ塗り、コテ塗り、ローラー塗りなど人の手で塗布する方法や、リシンガンなどのスプレーガン等を用いて圧縮エアを用いて吹き付けて施工する方法、ポンプで圧送した断面修復材を型枠内にグラウトする方法、ポンプで圧送した断面修復材を圧縮エアを用いて吹き付けて施工する方法がある。但し、工程（ＩＶ）においては、大断面で施工する場合の施工効率化の点から、吹付法により積層することが好ましい。
[Method for cross-sectional repair of reinforced concrete structures]
The cross-sectional repair method for a reinforced concrete structure (hereinafter sometimes referred to as "this cross-sectional repair method") of the present invention includes the following four steps.
(I) A process of removing surface concrete in defective areas of an existing reinforced concrete structure until at least a portion of the reinforcing bars are exposed.
(II) A process of covering the exposed reinforcing bars with cross-section repair material A containing lithium nitrite as a rust preventive agent.
(III) A step of applying a primer layer forming material to the surface of the cross-section repair material A to form a primer layer.
(IV) A step of laminating a cross-section repair material B that does not contain lithium nitrite on the primer layer.
The step of covering the reinforcing bars with the cross-section repair material A in the above step (II), the step of applying the primer layer forming material in the above step (III), and the step of laminating the cross-section repair material B in the step (IV) are as follows. Any method is acceptable. Specifically, there are manual methods such as brushing, troweling, and roller painting, methods of spraying using compressed air using a spray gun such as a ricing gun, and cross-sectional repair methods that are applied using a pump. There are two methods: grouting the material into the formwork, and spraying cross-sectional repair material pumped with compressed air. However, in step (IV), from the viewpoint of increasing construction efficiency when constructing a large cross section, it is preferable to perform lamination by a spraying method.
なお、上記工程（III）において用いるプライマー層形成材料は、プライマー層を構成する材料として上記した材料と同様であり、アクリル系樹脂又はエチレン－酢酸ビニル系樹脂を含むものである。また、プライマー層形成材料の塗布量は、不揮発分の塗布量として、５～５０ｇ／ｍ２であることが好ましい。塗布量がこの範囲内であると、本発明の効果を十分に発揮することができる。
なお、上記（II）及び（IV）の工程において使用される、断面修復材Ａ及び断面修復材Ｂの材料は、上述の断面修復材Ａ及び断面修復材Ｂの材料と同様である。
The primer layer forming material used in step (III) above is the same as the material described above as the material constituting the primer layer, and contains an acrylic resin or an ethylene-vinyl acetate resin. Further, the coating amount of the primer layer forming material is preferably 5 to 50 g/m 2 in terms of non-volatile content. When the coating amount is within this range, the effects of the present invention can be fully exhibited.
The materials of the cross-section repair material A and cross-section repair material B used in the steps (II) and (IV) above are the same as those of the cross-section repair material A and cross-section repair material B described above.
また、上記工程（Ｉ）の後、前記工程（ＩＩ）の前に鉄筋に防錆剤を塗布して、防錆層を形成する工程を有することが、より防錆性を高めることができる点で好ましい。なお、防錆層を構成する材料等については、上述の通りである。 Further, after the above step (I) and before the above step (II), including the step of applying a rust preventive agent to the reinforcing steel to form a rust preventive layer can further improve the rust prevention property. It is preferable. Note that the materials constituting the anticorrosion layer are as described above.
さらに、本断面修復方法においては、工程（II）の後、工程（III）の開始前に、３時間以上の保持時間を有することが好ましい。該保持時間を有することで、より防錆効果を高めることができる。 Furthermore, in this cross-sectional repair method, it is preferable to have a holding time of 3 hours or more after step (II) and before starting step (III). By having this holding time, the rust prevention effect can be further enhanced.
以下、実施例及び比較例を用いて本発明を更に具体的に説明するが、本発明はその要旨を逸脱しない限り、下記の実施例に限定されるものではない。 Hereinafter, the present invention will be explained in more detail using Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it departs from the gist thereof.
（評価方法）
（１）付着強度の測定：供試体から直径７３ｍｍのコア供試体を採取し、引張り試験機で付着強度を測定した。なお、付着強度は３回測定を行った平均値を用いた。
（２）防錆性能の評価
試料サンプルの養生２８日後の試験体を気温４０℃、湿度９５％の環境に１５０日暴露後、丸鋼を取り出し、防錆性能を確認した。評価基準は以下の通りである。
〇；錆が認められない。
△；錆がわずかに認められた。
×；錆が認められた。
(Evaluation method)
(1) Measurement of adhesive strength: A core specimen with a diameter of 73 mm was taken from the specimen, and the adhesive strength was measured using a tensile tester. In addition, the average value of three measurements was used for the adhesion strength.
(2) Evaluation of rust prevention performance After 28 days of curing of the sample, the test specimen was exposed to an environment of 40°C and 95% humidity for 150 days, and then the round steel was taken out and the rust prevention performance was confirmed. The evaluation criteria are as follows.
○: No rust observed.
Δ: Slight rust was observed.
×: Rust was observed.
（使用材料）
（１）断面修復材の材料
断面修復材に用いた材料は、以下の通りである。表１に含有量を記載する。なお、後述するように、断面修復材の材料に亜硝酸リチウムを加えた断面修復材を断面修復材Ａとし、亜硝酸リチウムを加えない断面修復材を断面修復材Ｂとする。
・普通セメント：デンカ社製の普通ポルトランドセメント
・砂：新潟県糸魚川市産石灰砂
・ファイバー：ビニロンファイバー、繊維長６ｍｍ
・膨張材：ＣＳＡ＃２０（デンカ社製）
・粉末ポリマー：アクリル酸エステル系共重合体
・増粘剤：メチルセルロース
・プライマー層形成材料：ＲＩＳ２１１Ｅ（ＥＶＡ、デンカ社製）
(Materials used)
(1) Materials for cross-section repair material The materials used for the cross-section repair material are as follows. The contents are listed in Table 1. Note that, as will be described later, a cross-section repair material in which lithium nitrite is added to the cross-section repair material material is referred to as a cross-section repair material A, and a cross-section repair material to which lithium nitrite is not added is referred to as a cross-section repair material B.
・Ordinary cement: Ordinary Portland cement made by Denka ・Sand: Lime sand from Itoigawa City, Niigata Prefecture ・Fiber: Vinylon fiber, fiber length 6mm
・Expansion material: CSA#20 (manufactured by Denka)
・Powder polymer: Acrylic ester copolymer ・Thickener: Methylcellulose ・Primer layer forming material: RIS211E (EVA, manufactured by Denka)
実施例１
上記表１に示される含有量の材料をハンドミキサーで混合し、断面修復材Ａ及びＢに用いる修復材（ポリマーセメントモルタル）を得た。次いで、該ポリマーセメントモルタル１００質量部に対して、水を１２質量部、亜硝酸リチウムの固形分含有量を３質量部配合し、断面修復材Ａを得た。なお、断面修復材Ｂとしては、亜硝酸リチウムを混合しない点を除いて、断面修復材Ａと同じポリマーセメントモルタルを用い該ポリマーセメントモルタル１００質量部に対して、水を１３．５質量部配合し、断面修復材Ｂを得た。
付着強度試験に使用する試験体として、３００ｍｍ×３００ｍｍ×６０ｍｍの歩道板を準備し、これに断面修復材Ａを吹き付けた。断面修復材Ａの厚みは３０ｍｍであった。続いて、断面修復材Ａ上にプライマー層形成材料を刷毛で塗布した。プライマー層の不揮発分の塗布量は２５ｇ／ｍ２とした。プライマー層形成後、２４時間経過後に断面修復材Ｂを吹き付けて試験サンプルを得た。
また防錆性能の評価に使用する試験体として１００ｍｍ×１００ｍｍ×４０ｍｍの型枠の中心位置に長さ１００ｍｍの丸鋼φ１６ｍｍを配置した。これに断面修復材Ａを１００ｍｍ×１００ｍｍ×３０ｍｍとし吹き付けた。断面修復材Ａの厚みは３０ｍｍであった。続いて、断面修復材Ａ上にプライマー層形成材料を刷毛で塗布した。プライマー層の不揮発分の塗布量は２５ｇ／ｍ２とした。プライマー層形成後、２４時間経過後に断面修復材Ｂを吹き付けて試験サンプルを得た。
上記で作製した試験サンプルについて、２０℃、相対湿度６０％の条件で７日間養生した後、上記方法にて、断面修復材Ａと断面修復材Ｂの付着強度を測定した。結果を表２に示す。また防錆性能の評価結果を表２に示す。
また、プライマー層形成材料を吹き付けた後、断面修復材Ｂを吹き付けるまでの時間（以下、「打ち継ぎ時間」と記載する。）を４日間とした場合の評価結果を併せて記載する。なお、養生時間を２８日間とした結果を併せて記載する。
Example 1
The materials having the contents shown in Table 1 above were mixed using a hand mixer to obtain a repair material (polymer cement mortar) used for cross-sectional repair materials A and B. Next, 12 parts by mass of water and 3 parts by mass of lithium nitrite were added to 100 parts by mass of the polymer cement mortar to obtain a cross-sectional repair material A. In addition, as cross-section repair material B, the same polymer cement mortar as cross-section repair material A was used, except that lithium nitrite was not mixed, and 13.5 parts by mass of water was mixed with 100 parts by mass of the polymer cement mortar. A cross-section repair material B was obtained.
A sidewalk board measuring 300 mm x 300 mm x 60 mm was prepared as a test specimen used in the adhesion strength test, and cross-sectional repair material A was sprayed onto it. The thickness of the cross-sectional repair material A was 30 mm. Subsequently, a primer layer forming material was applied onto the cross-section repair material A with a brush. The coating amount of the nonvolatile component of the primer layer was 25 g/m 2 . After 24 hours had elapsed after the primer layer was formed, cross-section repair material B was sprayed to obtain a test sample.
Further, as a test specimen used for evaluating the rust prevention performance, a 16 mm round steel with a length of 100 mm was placed at the center of a formwork of 100 mm x 100 mm x 40 mm. Cross-sectional repair material A was sprayed onto this in a size of 100 mm x 100 mm x 30 mm. The thickness of the cross-sectional repair material A was 30 mm. Subsequently, a primer layer forming material was applied onto the cross-section repair material A with a brush. The coating amount of the nonvolatile component of the primer layer was 25 g/m 2 . After 24 hours had elapsed after the primer layer was formed, cross-section repair material B was sprayed to obtain a test sample.
After curing the test sample prepared above for 7 days at 20° C. and 60% relative humidity, the adhesion strength of cross-section repair material A and cross-section repair material B was measured using the above method. The results are shown in Table 2. Table 2 also shows the evaluation results of rust prevention performance.
In addition, the evaluation results when the time from spraying the primer layer forming material to spraying the cross-section repair material B (hereinafter referred to as "spraying time") was set to 4 days are also described. In addition, the results with a curing time of 28 days are also described.
比較例１
実施例１において、プライマー層を形成しなかったこと以外は、実施例１と同様にして、試験サンプルを得た。実施例１と同様にして、断面修復材Ａと断面修復材Ｂの付着強度を測定した。結果を表２に示す。また防錆性能の評価結果を表２に示す。
Comparative example 1
A test sample was obtained in the same manner as in Example 1 except that the primer layer was not formed. In the same manner as in Example 1, the adhesion strength of cross-sectional repair material A and cross-sectional repair material B was measured. The results are shown in Table 2. Table 2 also shows the evaluation results of rust prevention performance.
実施例２
実施例１において、亜硝酸リチウムの固形分含有量を０．５質量部としたこと以外は、実施例１と同様にして試験サンプルを得た。
Example 2
A test sample was obtained in the same manner as in Example 1, except that the solid content of lithium nitrite was 0.5 parts by mass.
比較例２
実施例２において、プライマー層を形成しなかったこと以外は、実施例２と同様にして、試験サンプルを得た。実施例２と同様にして、断面修復材Ａと断面修復材Ｂの付着強度を測定した。結果を表２に示す。また防錆性能の評価結果を表２に示す。
Comparative example 2
A test sample was obtained in the same manner as in Example 2, except that the primer layer was not formed. In the same manner as in Example 2, the adhesion strength of cross-sectional repair material A and cross-sectional repair material B was measured. The results are shown in Table 2. Table 2 also shows the evaluation results of rust prevention performance.
実施例３
実施例１において、亜硝酸リチウムの固形分含有量を３０質量部としたこと以外は、実施例１と同様にして試験サンプルを得た。
Example 3
A test sample was obtained in the same manner as in Example 1, except that the solid content of lithium nitrite was 30 parts by mass.
比較例３
実施例３において、プライマー層を形成しなかったこと以外は、実施例３と同様にして、試験サンプルを得た。実施例３と同様にして、断面修復材Ａと断面修復材Ｂの付着強度を測定した。結果を表２に示す。また防錆性能の評価結果を表２に示す。
Comparative example 3
A test sample was obtained in the same manner as in Example 3, except that the primer layer was not formed. In the same manner as in Example 3, the adhesion strength of cross-sectional repair material A and cross-sectional repair material B was measured. The results are shown in Table 2. Table 2 also shows the evaluation results of rust prevention performance.
本発明によれば、亜硝酸リチウムの使用量を抑えて、効果的に鉄筋防錆効果を得ることができ、低コストで鉄筋コンクリート構造物の修復を行うことができる。したがって、土木建築分野において、極めて有用な技術である。 According to the present invention, it is possible to suppress the amount of lithium nitrite used, effectively obtain a reinforcing steel rust prevention effect, and repair a reinforced concrete structure at low cost. Therefore, it is an extremely useful technology in the field of civil engineering and construction.
１０ 補修材
１１ 亜硝酸リチウム混入断面修復材Ａ
１２ 亜硝酸リチウム非混入断面修復材Ｂ
１３ プライマー層
２０ 鉄筋
３０ コンクリート
３１ コンクリート外表面
３２ 表層コンクリート
４０ 亜硝酸イオン
10 Repair material 11 Lithium nitrite mixed cross section repair material A
12 Lithium nitrite-free cross-section repair material B
13 Primer layer 20 Rebar 30 Concrete 31 Concrete outer surface 32 Surface concrete 40 Nitrite ion
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| JP2005336952A (en) | 2004-05-31 | 2005-12-08 | Denki Kagaku Kogyo Kk | Cross section repair construction method for concrete deteriorated part and non-contracting polymer cement mortar used in it |
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