JPS6210948B2 - - Google Patents
Info
- Publication number
- JPS6210948B2 JPS6210948B2 JP2947280A JP2947280A JPS6210948B2 JP S6210948 B2 JPS6210948 B2 JP S6210948B2 JP 2947280 A JP2947280 A JP 2947280A JP 2947280 A JP2947280 A JP 2947280A JP S6210948 B2 JPS6210948 B2 JP S6210948B2
- Authority
- JP
- Japan
- Prior art keywords
- mortar
- steel
- concrete
- aqueous solution
- hydroxybenzotriazole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 30
- 239000010959 steel Substances 0.000 claims description 30
- 239000004570 mortar (masonry) Substances 0.000 claims description 21
- 239000000463 material Substances 0.000 claims description 20
- 239000007864 aqueous solution Substances 0.000 claims description 18
- 239000004567 concrete Substances 0.000 claims description 17
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 15
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 14
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 14
- 239000000920 calcium hydroxide Substances 0.000 claims description 14
- ASOKPJOREAFHNY-UHFFFAOYSA-N 1-Hydroxybenzotriazole Chemical compound C1=CC=C2N(O)N=NC2=C1 ASOKPJOREAFHNY-UHFFFAOYSA-N 0.000 claims description 13
- 150000001875 compounds Chemical class 0.000 claims description 11
- 230000002265 prevention Effects 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 5
- 239000004568 cement Substances 0.000 description 13
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- AZFNGPAYDKGCRB-XCPIVNJJSA-M [(1s,2s)-2-amino-1,2-diphenylethyl]-(4-methylphenyl)sulfonylazanide;chlororuthenium(1+);1-methyl-4-propan-2-ylbenzene Chemical compound [Ru+]Cl.CC(C)C1=CC=C(C)C=C1.C1=CC(C)=CC=C1S(=O)(=O)[N-][C@@H](C=1C=CC=CC=1)[C@@H](N)C1=CC=CC=C1 AZFNGPAYDKGCRB-XCPIVNJJSA-M 0.000 description 6
- 238000005260 corrosion Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000000835 fiber Substances 0.000 description 6
- 235000010289 potassium nitrite Nutrition 0.000 description 6
- 239000004304 potassium nitrite Substances 0.000 description 6
- 150000002826 nitrites Chemical class 0.000 description 5
- 239000004576 sand Substances 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000011150 reinforced concrete Substances 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- DZPYZQDOGIPDDF-UHFFFAOYSA-N calcium;1-hydroxybenzotriazole Chemical compound [Ca].C1=CC=C2N(O)N=NC2=C1 DZPYZQDOGIPDDF-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000011210 fiber-reinforced concrete Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
Description
コンクリートあるいはモルタル中に埋設する補
強用の鋼材としては一般に鋼棒、鋼線、鋼網、鋼
繊維、鋼箔が用いられている。これらの鋼材は普
通セメントペーストの高アルカリ性の環境にあつ
て発錆や腐食しにくい状態が保たれている。しか
し鉄筋コンクリートでは一旦ひび割れが起ると、
セメントの中性化の進行や水分の浸入などにより
鋼材の腐食が進行する。また鋼繊維補強コンクリ
ートやモルタルの場合には鋼繊維が均一に混入分
布しているため、表面近傍にも存在し、さらに一
部は表面に露出している。したがつて腐食環境に
さらされやすく、鉄錆が表面に浮き出てくる。
いずれにしても鋼材の錆の発生や腐食の進行
は、コンクリートあるいはモルタルの耐久性を低
下させ構造物の老化をきたす。このような錆の発
生を防止するための方法として一部で亜硝酸カリ
ウムをセメントに混練して使用することにより補
強鋼材の発錆を防止することが行なわれている。
しかし亜硝酸塩は毒性の点で問題があり、また鋼
材に対する防錆性は亜硝酸塩の水溶液中あるいは
湿潤雰囲気中にあつては防錆性を発揮するが、亜
硝酸塩で処理された鋼材が空気中に暴露された時
には急速に防錆効果が低下し、むしろ悪影響を及
ぼすのが通例である。
亜硝酸塩を添加したコンクリートあるいはモル
タルは経時とともにひび割れを生じ空気中に暴露
されることによつて埋め込んだ鋼材に対する防錆
性が低下し、錆が発生しそして付着強度を劣化さ
せる。
本発明の１−ヒドロキシベンゾトリアゾール
と、該化合物に対して当量以上の水酸化カルシウ
ムを用いる理由は、１−ヒドロキシベンゾトリア
ゾール単独の水溶性は酸性を示し、水酸化カルシ
ウムを当量以上加えることにより中和されると同
時に、アルカリ領域に保持することができる。水
酸化カルシウムを過剰に添加して懸濁した水溶液
になつても防錆効果に影響はない。水酸化カルシ
ウムはセメント中に含まれる一成分でもあり、ま
た溶出したCa2+も同じくセメント成分であり有
益な役割こそあれ悪影響を及ぼさない。
本発明の１−ヒドロキシベンゾトリアゾール
と、該化合物に対して当量以上の水酸化カルシウ
ムを含有する水溶液〔例えば１−ヒドロキシベン
ゾトリアゾール1.0％に対し水酸化カルシウム0.4
％（1.5倍当量）〕を用いてセメントを混練し補強
鋼材を埋設したコンクリートあるいはモルタルの
場合、ひび割を生じて空気中に暴露されても防錆
効果を損なうことがない。
さらには１−ヒドロキシベンゾトリアゾールと
該化合物に対して当量以上の水酸化カルシウムを
含有する水溶液によつて補強鋼材をあらかじめ表
面処理し、該鋼材を上記組成の水溶液にて混練し
たコンクリートあるいはモルタルに埋設させるこ
とによつて相乗効果を発揮し補強鋼材のより一層
の優れた防錆性及びコンクリートあるいはモルタ
ルとの密着性が得られる。
上記の水溶液すなわち１−ヒドロキシベンゾト
リアゾール・カルシウム塩のセメントに対する添
加濃度は0.01％〜５％の範囲でよく、好ましくは
0.3〜３％の範囲が埋設する鋼材の防錆性及び密
着性そして経済的にも望ましい。
またコンクリートあるいはモルタルに埋設され
る鋼材をあらかじめ表面処理する方法は、鋼材に
１−ヒドロキシベンゾトリアゾールと該化合物に
対して当量以上の水酸化カルシウムを含有する水
溶液を浸漬、スプレーなどの手段で付着させたの
ち乾燥する。この際に使用する前記水溶液の濃度
は0.05〜３％の範囲でよいが、防錆性および経済
性より0.1〜１％が好ましい。
本発明によるコンクリートあるいはモルタルに
補強鋼材を複合させることによつて従来の亜硝酸
カリウムや他の亜硝酸塩を添加したコンクリート
あるいはモルタルに比べて鋼材の防錆性やコンク
リートに対する密着性に優れた効果を発揮する。
以下実施例について説明する。
実施例 １
１−ヒドロキシベンゾトリアゾールと該化合物
に対して２倍当量の水酸化カルシウムを加えた水
溶液を用いて、セメントに対して前記化合物の添
加量が0.2％と２％になるように水分を加えて練
り混ぜた後、通常の熱延材のSR−24の鉄筋を埋
め込んだ鉄筋コンクリート供試体に作製した。な
お海砂対策上、問題とされる塩分量は砂中に換算
して0.2％迄の事例が多いので砂中塩分を0.2％と
した。水セメント比を建築用の0.65とし、カブリ
厚みは通常の２cmの供試体と、カブリ厚み４cmと
厚くして予め人工的にひび割れを入れて外気の影
響を受けやすくした２種類の供試体を作製した。
いずれも生コンクリートを打設後28日間水中標準
養生した後暴露試験に供した。この供給体を海浜
地帯に５年間暴露したのちコンクリート供試体に
発生したひび割れ状況及びコンクリート供試体を
破砕後、鉄筋を取り出してその発錆面積、最大局
部腐食速度を調べた。
なお比較供試体は従来使われている亜硝酸カリ
ウムを添加したコンクリートを用いた。いずれの
実験も各々２個の供試体を用いて行なつた。結果
を第１表に示す。
Steel rods, steel wires, steel nets, steel fibers, and steel foils are generally used as reinforcing steel materials buried in concrete or mortar. These steel materials remain resistant to rust and corrosion in the highly alkaline environment of ordinary cement paste. However, once cracks occur in reinforced concrete,
Corrosion of steel progresses due to the progress of carbonation of cement and the infiltration of moisture. Furthermore, in the case of steel fiber-reinforced concrete or mortar, steel fibers are mixed and distributed uniformly, so they exist near the surface, and some of them are exposed at the surface. Therefore, it is easily exposed to a corrosive environment, and iron rust appears on the surface. In any case, the occurrence of rust and progression of corrosion in steel materials reduces the durability of concrete or mortar and causes aging of the structure. As a method for preventing the occurrence of such rust, some methods include mixing potassium nitrite into cement to prevent rust from forming on reinforcing steel materials.
However, nitrites pose a problem in terms of toxicity, and although they exhibit rust-preventive properties for steel materials in an aqueous solution of nitrites or in a humid atmosphere, steel materials treated with nitrites exhibit rust-preventive properties in the air. When exposed to water, the anti-corrosion effect rapidly decreases, and in fact it usually has a negative effect. Concrete or mortar containing nitrites cracks over time and is exposed to the air, reducing its anti-corrosion properties for embedded steel materials, causing rust and deteriorating bonding strength. The reason for using the 1-hydroxybenzotriazole of the present invention and calcium hydroxide in an amount equivalent to or more of the compound is that the water solubility of 1-hydroxybenzotriazole alone is acidic, and by adding more than an equivalent amount of calcium hydroxide, the water solubility of 1-hydroxybenzotriazole alone is acidic. It can be maintained in the alkaline region while at the same time being hydrated. Even if an excessive amount of calcium hydroxide is added to form a suspended aqueous solution, the antirust effect is not affected. Calcium hydroxide is a component contained in cement, and eluted Ca 2+ is also a component of cement, and although it plays a beneficial role, it does not have any negative effects. An aqueous solution containing the 1-hydroxybenzotriazole of the present invention and calcium hydroxide in an amount equivalent or more to the compound [for example, 1.0% of 1-hydroxybenzotriazole to 0.4% calcium hydroxide]
% (1.5 times equivalent)], the rust prevention effect will not be lost even if the concrete or mortar is mixed with cement and embedded with reinforcing steel, even if it cracks and is exposed to the air. Furthermore, the reinforcing steel material is surface-treated in advance with an aqueous solution containing 1-hydroxybenzotriazole and calcium hydroxide in an amount equivalent to or more than the compound, and the steel material is buried in concrete or mortar mixed with an aqueous solution having the above composition. By doing so, a synergistic effect is exhibited, and even better rust prevention properties and adhesion with concrete or mortar of the reinforcing steel material can be obtained. The concentration of the above aqueous solution, i.e., 1-hydroxybenzotriazole calcium salt, added to the cement may be in the range of 0.01% to 5%, preferably
A content in the range of 0.3 to 3% is desirable from the viewpoint of rust prevention and adhesion of the buried steel material, as well as economical considerations. In addition, a method for pre-surface treatment of steel materials to be buried in concrete or mortar is to apply an aqueous solution containing 1-hydroxybenzotriazole and calcium hydroxide in an amount equivalent to or more than the compound to the steel material by means such as dipping or spraying. Dry afterwards. The concentration of the aqueous solution used at this time may be in the range of 0.05 to 3%, but is preferably 0.1 to 1% from the viewpoint of rust prevention and economy. By combining reinforcing steel with concrete or mortar according to the present invention, it exhibits superior rust prevention properties of steel and adhesion to concrete compared to conventional concrete or mortar containing potassium nitrite or other nitrites. do.
Examples will be described below. Example 1 Using an aqueous solution containing 1-hydroxybenzotriazole and calcium hydroxide in an amount twice equivalent to the compound, water was added so that the amount of the compound added to the cement was 0.2% and 2%. After adding and mixing, a reinforced concrete specimen was fabricated with embedded SR-24 reinforcing steel, which is a regular hot-rolled material. In addition, in terms of sea sand countermeasures, the amount of salt that is a problem is often up to 0.2% when converted into sand, so the salt content in sand was set at 0.2%. The water-cement ratio was set to 0.65 for construction, and two types of specimens were created: one with a normal fog thickness of 2 cm, and the other with a thick fog thickness of 4 cm and artificially cracked in advance to make it more susceptible to the effects of outside air. did.
In both cases, the ready-mixed concrete was placed and cured in water for 28 days before being subjected to an exposure test. After this supply body was exposed to a seashore area for 5 years, the cracks that occurred in the concrete specimen and after crushing the concrete specimen, the reinforcing bars were taken out and their rusted area and maximum local corrosion rate were examined. The comparative specimen used was concrete to which potassium nitrite was added, which is conventionally used. Each experiment was conducted using two specimens. The results are shown in Table 1.
【表】【table】
【表】
実施例 ２
１−ヒドロキシベンゾトリアゾールと該化合物
に対して1.5倍当量の水酸化カルシウムを加えた
組成の0.5％水溶液にてセメントを混練（該水溶
液／セメント＝１：２）した上澄液に鋼繊維
（0.35×0.6×30mm）を浸した後、風乾してから大
気中に放置して発錆状況を調べた。比較のために
亜硝酸カリウムを添加した場合の結果とあわせて
第２表に結果を示した。
実施例 ３
１−ヒドロキシベンゾトリアゾールと、該化合
物に対して３倍当量の水酸化カルシウムを加えた
組成の１％水溶液にてモルタル（該水溶液／セメ
ント／砂＝１：２：４）を混練し、これに鋼繊維
（0.35×0.6×30mm）を埋込み、28日間水中養生し
て供試体とした。この供試体を所定の期間大気中
に放置してからモルタルに発生したひび割れ状況
及び供試体の鋼材の付着強度を調べた。また供試
体破砕後、鋼繊維を取り出してモルタル内での発
錆状態を調べた。
従来法として亜硝酸カリウムを使用した結果と
ともに第３表に結果を示した。
実施例 ４
実施例３と同様に混練したモルタル中に、あら
かじめ表面処理（１−ヒドロキシベンゾトリアゾ
ールと該化合物に対して1.5倍当量の水酸化カル
シウムを加えた組成の0.5％水溶液に浸漬した後
乾燥）した鋼繊維（0.35×0.6×30mm）を埋込
み、28日間水中養生して供試体とした。供試体を
所定の期間大期中に放置してからモルタルに発生
したひび割れ状況及び供試体の鋼材の付着強度を
調べた。また供試体を破砕後、該鋼材のモルタル
内での防錆性を調べた。
なお比較供試体は従来使われている亜硝酸カリ
ウムを１％量添加した水溶液にモルタル（該水溶
液／セメント／砂＝１：２：４）を混練し、実施
例３及び４の鋼材をそれぞれ埋込んだ供試体を用
いた。結果を第４表に示す。[Table] Example 2 Supernatant obtained by kneading cement with a 0.5% aqueous solution containing 1-hydroxybenzotriazole and 1.5 times equivalent amount of calcium hydroxide relative to the compound (aqueous solution/cement = 1:2) After immersing steel fibers (0.35 x 0.6 x 30 mm) in the solution, they were air-dried and left in the air to examine the rusting state. For comparison, the results are shown in Table 2 together with the results when potassium nitrite was added. Example 3 Mortar (aqueous solution/cement/sand = 1:2:4) was kneaded with a 1% aqueous solution containing 1-hydroxybenzotriazole and calcium hydroxide in an amount three times the amount of the compound. Steel fibers (0.35 x 0.6 x 30 mm) were embedded in this, and the specimen was cured in water for 28 days. After this specimen was left in the atmosphere for a predetermined period of time, the cracks that had occurred in the mortar and the adhesion strength of the steel material of the specimen were examined. After crushing the specimen, the steel fibers were taken out and the state of rust in the mortar was examined. The results are shown in Table 3 along with the results using potassium nitrite as a conventional method. Example 4 In a mortar kneaded in the same manner as in Example 3, surface treatment was performed (immersed in a 0.5% aqueous solution containing 1-hydroxybenzotriazole and calcium hydroxide in an amount equivalent to 1.5 times the compound) and then dried. ) steel fibers (0.35 x 0.6 x 30 mm) were embedded and cured in water for 28 days to prepare a specimen. After the specimen was left for a predetermined period of time, the cracks that occurred in the mortar and the adhesion strength of the steel of the specimen were investigated. After crushing the specimen, the rust prevention properties of the steel material in mortar were examined. The comparative specimens were made by mixing mortar (aqueous solution/cement/sand = 1:2:4) in a conventionally used aqueous solution to which 1% potassium nitrite was added, and embedding the steel materials of Examples 3 and 4, respectively. A specimen was used. The results are shown in Table 4.
【表】【table】
【表】【table】
Claims (1)
合物に対して当量以上の水酸化カルシウムを含有
する水溶液を用いて混練したコンクリートあるい
はモルタル中に鋼材を埋設することを特徴とする
コンクリートあるいはモルタル中の鋼材の防錆方
法。 ２ あらかじめ１−ヒドロキシベンゾトリアゾー
ルと該化合物に対し当量以上の水酸化カルシウム
を含有する水溶液にて表面処理した鋼材を使用す
ることを特徴とする特許請求の範囲第１項記載の
コンクリートあるいはモルタル中の鋼材の防錆方
法。[Scope of Claims] 1. A concrete or mortar in which a steel material is embedded in concrete or mortar kneaded using an aqueous solution containing 1-hydroxybenzotriazole and calcium hydroxide in an amount equivalent to or more than the compound. Rust prevention method for steel in mortar. 2. In concrete or mortar according to claim 1, the steel material is surface-treated with an aqueous solution containing calcium hydroxide in an amount equivalent to or more than 1-hydroxybenzotriazole and the compound. Rust prevention method for steel materials.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2947280A JPS56125259A (en) | 1980-03-08 | 1980-03-08 | Rust prevention for steel material in concrete or mortar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2947280A JPS56125259A (en) | 1980-03-08 | 1980-03-08 | Rust prevention for steel material in concrete or mortar |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56125259A JPS56125259A (en) | 1981-10-01 |
| JPS6210948B2 true JPS6210948B2 (en) | 1987-03-09 |
Family
ID=12277033
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2947280A Granted JPS56125259A (en) | 1980-03-08 | 1980-03-08 | Rust prevention for steel material in concrete or mortar |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS56125259A (en) |
-
1980
- 1980-03-08 JP JP2947280A patent/JPS56125259A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56125259A (en) | 1981-10-01 |
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