JP6758841B2

JP6758841B2 - Deterioration detection method and corrosion sensor

Info

Publication number: JP6758841B2
Application number: JP2016016250A
Authority: JP
Inventors: 幸俊井坂; 早野　博幸; 博幸早野; 愛吉田; 玲江里口
Original assignee: Taiheiyo Cement Corp
Current assignee: Taiheiyo Cement Corp
Priority date: 2015-03-27
Filing date: 2016-01-29
Publication date: 2020-09-23
Anticipated expiration: 2036-01-29
Also published as: JP6649142B2; JP2016186482A; JP6660749B2; JP2016188858A; JP6626285B2; JP6621611B2; JP2016188848A; JP2016188849A; JP2016186483A; JP2016188850A

Description

本発明は、鋼材に塗布された保護塗料の劣化進行状況を検出する技術に関する。 The present invention relates to a technique for detecting the progress of deterioration of a protective coating material applied to a steel material.

従来から、鉄橋やプラントなどの鋼材を用いた構造物では、鋼材に錆が生じないように保護塗料が用いられている。この保護塗料は、腐食因子の浸透や紫外線などにより、時間の経過と共に劣化する。このため、蛍光Ｘ線により厚みを測定することで劣化を検出する手法や、鋼材にケーブルを接続して腐食に伴う電気的特性の変化を測定することで劣化を検出する手法が提案されている。しかし、前者は現場での測定に不向きであり、高価であるという欠点があり、後者は感度や精度劣るという欠点があった。このような事情から、これらの手法は採用しがたく、従来は、主に、目視によって保護塗料の剥離や発錆の点検が行なわれていた。しかし、単に目視で点検する手法では、計画的に保護塗料を塗り替えたり、将来的に、いつ塗り替えるべきであるかを予測したりすることは容易ではない。その結果、従来は、構造物に対し、定期的に全面的な保護塗料の塗り替えが行なわれていた。 Conventionally, in structures using steel materials such as railway bridges and plants, protective paints have been used to prevent rusting of the steel materials. This protective paint deteriorates over time due to the penetration of corrosive factors and ultraviolet rays. For this reason, a method of detecting deterioration by measuring the thickness with fluorescent X-rays and a method of detecting deterioration by connecting a cable to a steel material and measuring a change in electrical characteristics due to corrosion have been proposed. .. However, the former has the disadvantage of being unsuitable for on-site measurement and is expensive, and the latter has the disadvantage of being inferior in sensitivity and accuracy. Due to such circumstances, it is difficult to adopt these methods, and conventionally, peeling of the protective paint and inspection of rust have been mainly performed visually. However, it is not easy to systematically repaint the protective paint or predict when it should be repainted in the future by simply visual inspection. As a result, conventionally, the entire structure has been regularly repainted with the protective paint.

特開２０１３−０５３９１６号公報Japanese Unexamined Patent Publication No. 2013-053916 特開２０１２−２０８０８８号公報Japanese Unexamined Patent Publication No. 2012-208088

しかしながら、構造物の保護塗膜の劣化は、一様に進むわけではないため、一部の劣化が進んでいたとしても、他の一部には、まだ塗り直しを必要としない箇所がある可能性がある。それにもかかわらず、従来から、構造物に対し、定期的に全面的な保護塗料の塗り替えを行なっていたため、無用なコストがかかってしまっていた。鋼材の健全性は保護塗料の健全性によって管理しているため、構造物の各所において、塗り直すべき時期を把握することができれば、安全性を確保しつつ、ライフサイクルコストを削減することが可能となる。一方、鋼材に塗布された保護塗膜は薄いため、塗膜の劣化状況の把握や管理は容易ではない。 However, the deterioration of the protective coating film of the structure does not proceed uniformly, so even if some deterioration progresses, there may be some parts that do not yet need to be repainted. There is sex. Nevertheless, conventionally, the entire structure has been repainted with a protective paint on a regular basis, resulting in unnecessary costs. Since the soundness of steel materials is controlled by the soundness of protective paints, it is possible to reduce life cycle costs while ensuring safety if it is possible to know when to repaint in various parts of the structure. It becomes. On the other hand, since the protective coating film applied to the steel material is thin, it is not easy to grasp and manage the deterioration state of the coating film.

本発明は、このような事情に鑑みてなされたものであり、鋼材の保護塗膜の劣化進行状況を検出し、保護塗料を塗り直すべき時期を把握することができる劣化検出方法および腐食センサを提供することを目的とする。 The present invention has been made in view of such circumstances, and provides a deterioration detection method and a corrosion sensor capable of detecting the deterioration progress of the protective coating film of a steel material and grasping the time when the protective coating film should be reapplied. The purpose is to provide.

（１）上記の目的を達成するために、本発明は、以下のような手段を講じた。すなわち、本発明の劣化検出方法は、鋼材に塗布された保護塗料の劣化進行状況を検出する劣化検出方法であって、光ファイバセンサを鋼材の表面に貼付する工程と、前記光ファイバセンサが貼付された鋼材に対し、前記光ファイバセンサが被覆されるように保護塗料を塗布する工程と、前記光ファイバセンサに計測器を接続し、前記光ファイバセンサ中を伝搬する光波の特性変化に基づいて、ひずみを測定する工程と、を少なくとも含み、前記測定したひずみに基づいて、前記鋼材に塗布された保護塗料の劣化進行状況を検出することを特徴とする。 (1) In order to achieve the above object, the present invention has taken the following measures. That is, the deterioration detection method of the present invention is a deterioration detection method for detecting the deterioration progress status of the protective coating applied to the steel material, and is a step of attaching the optical fiber sensor to the surface of the steel material and the application of the optical fiber sensor. Based on the step of applying a protective coating to the steel material so that the optical fiber sensor is covered, and the characteristic change of the light wave propagating in the optical fiber sensor by connecting a measuring instrument to the optical fiber sensor. The step of measuring the strain is included, and the deterioration progress of the protective coating material applied to the steel material is detected based on the measured strain.

このように、細径である光ファイバセンサを用いることから、厚さが薄い保護塗膜と鋼材との間に設置することが可能となる。また、塗膜の欠損部も少ない。また、鋼材の保護塗膜の劣化進行状況を検出し、保護塗料を塗り直すべき時期を把握することができることから、その結果として、効果的で、かつ効率的な塗装サイクルを設定することが可能となり、コストの削減を図ることが可能となる。 As described above, since the optical fiber sensor having a small diameter is used, it is possible to install the sensor between the thin protective coating film and the steel material. In addition, there are few defects in the coating film. In addition, since it is possible to detect the deterioration progress of the protective coating film of the steel material and grasp the time when the protective coating film should be reapplied, as a result, it is possible to set an effective and efficient coating cycle. Therefore, it is possible to reduce the cost.

（２）また、本発明の劣化検出方法は、鋼材に塗布された保護塗料の劣化進行状況を検出する劣化検出方法であって、光ファイバセンサを金属板の表面に貼付する工程と、前記光ファイバセンサが貼付された金属板を鋼材の表面に貼付する工程と、前記金属板が貼付された鋼材に対し、前記光ファイバセンサが被覆されるように保護塗料を塗布する工程と、前記光ファイバセンサに計測器を接続し、前記光ファイバセンサ中を伝搬する光波の特性変化に基づいて、ひずみを測定する工程と、を少なくとも含み、前記測定したひずみに基づいて、前記鋼材に塗布された保護塗料の劣化進行状況を検出することを特徴とする。 (2) Further, the deterioration detection method of the present invention is a deterioration detection method for detecting the deterioration progress status of the protective coating applied to the steel material, the step of attaching the optical fiber sensor to the surface of the metal plate, and the light. A step of sticking a metal plate to which a fiber sensor is attached to the surface of a steel material, a step of applying a protective paint to the steel material to which the metal plate is attached so that the optical fiber sensor is covered, and the optical fiber. A protection applied to the steel material based on the measured strain, including at least a step of connecting a measuring instrument to the sensor and measuring the strain based on the characteristic change of the light wave propagating in the optical fiber sensor. It is characterized by detecting the progress of deterioration of the paint.

このように、光ファイバセンサを金属板の表面に貼付するので、現地（現場）で光ファイバを張付ける作業が不要となり、金属板を張付けるだけの容易な作業となる。また、現地でなく、室内で光ファイバを適度な緊張力で金属板に取り付けることができ、検知の精度が高くなる。したがって、現場における施工も通常のように実施され、手間が増えることはない。また、金属板の保護塗膜の厚さを段階的に正確に変化させることが可能となるので、保護塗料の劣化進行状況を段階的に検出することが可能となる。 Since the optical fiber sensor is attached to the surface of the metal plate in this way, the work of attaching the optical fiber at the site (site) becomes unnecessary, and the work is as simple as attaching the metal plate. In addition, the optical fiber can be attached to the metal plate with an appropriate tension force not in the field but indoors, and the detection accuracy is improved. Therefore, on-site construction is also carried out as usual, and the labor does not increase. Further, since the thickness of the protective coating film on the metal plate can be changed stepwise and accurately, it is possible to detect the progress of deterioration of the protective coating stepwise stepwise.

（３）また、本発明の劣化検出方法は、光ファイバセンサを鋼材又は金属板の表面に貼付する前に、防錆被膜を鋼材又は金属板の表面に貼付したダミーセンサを設け、ダミーセンサを用いて腐食以外の要因で生じたひずみを検出し、前記検出したひずみを補正するステップをさらに含むことを特徴とする。 (3) Further, in the deterioration detection method of the present invention, before the optical fiber sensor is attached to the surface of the steel material or metal plate, a dummy sensor having a rust preventive coating attached to the surface of the steel material or metal plate is provided, and the dummy sensor is provided. It is characterized by further including a step of detecting a strain generated by a factor other than corrosion and correcting the detected strain.

この構成により、腐食によるひずみと、そうでないひずみ、すなわち温度や外力によるひずみを識別することが可能となる。これにより、温度や外力によるひずみの影響を取り除くことが可能となる。その結果、高い精度で腐食によるひずみのみを検出することが可能となる。 This configuration makes it possible to distinguish between strain due to corrosion and strain that is not, that is, strain due to temperature or external force. This makes it possible to remove the influence of strain due to temperature and external force. As a result, it is possible to detect only the strain due to corrosion with high accuracy.

（４）また、本発明の劣化検出方法は、前記貼付された光ファイバセンサの表面に、腐食因子が浸透しない防錆処理が施されたダミーセンサを設け、ダミーセンサを用いて腐食以外の要因で生じたひずみを検出し、前記検出したひずみを補正するステップをさらに含むことを特徴とする。 (4) Further, in the deterioration detection method of the present invention, a dummy sensor that has been subjected to a rust preventive treatment that prevents corrosion factors from penetrating is provided on the surface of the attached optical fiber sensor, and factors other than corrosion are used using the dummy sensor. It is characterized by further including a step of detecting the strain generated in the above and correcting the detected strain.

（５）また、本発明の腐食センサは、鋼材に塗布された保護塗料の劣化進行状況を検出する腐食センサであって、光ファイバセンサと、前記光ファイバセンサを保持する鋼材と、前記光ファイバセンサおよび前記光ファイバセンサが貼付された鋼材を被覆する保護塗料と、を備え、前記鋼材の腐食により光ファイバセンサ中を伝搬する光波の特性に変化が生じることを特徴とする。 (5) Further, the corrosion sensor of the present invention is a corrosion sensor that detects the deterioration progress of the protective coating applied to the steel material, and is an optical fiber sensor, a steel material holding the optical fiber sensor, and the optical fiber. The sensor and the protective coating material for coating the steel material to which the optical fiber sensor is attached are provided, and the characteristics of the light wave propagating in the optical fiber sensor are changed due to the corrosion of the steel material.

この構成により、現地（現場）でセンサを取り付ける作業が不要となり、本センサを対象物と同じ環境に設置するだけの作業となる。また、現地でなく、室内で光ファイバを適度な緊張力で張付けることができ、検知の精度が高くなる。したがって、現場における施工も通常のように実施され、手間が増えることはない。さらに、測定が容易な場所に設置することもできる。 This configuration eliminates the need to install the sensor on-site (on-site), and only installs this sensor in the same environment as the object. In addition, the optical fiber can be attached with an appropriate tension in the room instead of in the field, and the detection accuracy is improved. Therefore, on-site construction is also carried out as usual, and the labor does not increase. Furthermore, it can be installed in a place where measurement is easy.

本発明によれば、細径である光ファイバセンサを用いることから、厚さが薄い保護塗膜と鋼材との間に設置することが可能となる。また、塗膜の欠損部も少なくなる。また、鋼材の保護塗膜の劣化進行状況を検出し、保護塗料を塗り直すべき時期を把握することができることから、その結果として、効果的で、かつ効率的な塗装サイクルを設定することが可能となり、コストの削減を図ることが可能となる。 According to the present invention, since the optical fiber sensor having a small diameter is used, it is possible to install the sensor between the thin protective coating film and the steel material. In addition, the number of defects in the coating film is reduced. In addition, since it is possible to detect the deterioration progress of the protective coating film of the steel material and grasp the time when the protective coating film should be reapplied, as a result, it is possible to set an effective and efficient coating cycle. Therefore, it is possible to reduce the cost.

本発明に係る実施形態１を示す図である。It is a figure which shows Embodiment 1 which concerns on this invention. Ｈ鋼の側面にセンサを貼付し、保護塗料を塗布した様子を示す図である。It is a figure which shows the state which the sensor was attached to the side surface of H steel, and the protective paint was applied. 実施形態２に係るセンサの使用例を示す図である。It is a figure which shows the use example of the sensor which concerns on Embodiment 2. 鋼材に光ファイバセンサを有する金属板を張り付けて、保護塗膜を施した様子を示す図である。It is a figure which shows the state that the metal plate which has an optical fiber sensor is attached to the steel material, and the protective coating film is applied. 検証例に係る試験体を示す図である。It is a figure which shows the test piece which concerns on a verification example. 腐食環境下における経過時間とひずみとの関係を示すグラフである。It is a graph which shows the relationship between the elapsed time and strain in a corrosive environment. 光ファイバセンサを鋼材に３巻きとした検証結果を示すグラフである。It is a graph which shows the verification result which made 3 turns of an optical fiber sensor in a steel material. 検証例２に係る試験体の概要を示す図である。It is a figure which shows the outline of the test body which concerns on the verification example 2. 測定結果を示す図である。It is a figure which shows the measurement result.

本実施形態に係る腐食検出方法として、鋼材の表面に光ファイバセンサを貼り付ける場合を例示する。この腐食センサにおいては、鋼材そのものの腐食を検出することが可能である。鋼材が腐食すると、腐食生成物の体積膨張により光ファイバに伸びが生ずる。この伸びを、光ファイバセンサを介して、データロガー等の測定器で検出することによって、鋼材が腐食環境にあるのか否か、腐食因子が侵入してきたのかどうか、鋼材の腐食状況はどうかを診断することが可能となる。鋼材は、構造物に用いられている鋼材を使用してもよいし、別に鋼材を準備してセンサを設置してもよい。別に鋼材を準備してセンサを設置する場合は、測定対象と環境が同一である周辺部にセンサが移動したり脱落したりしないように設置する。構造物に用いられている鋼材を使用する場合は、別に鋼材を準備したり、取り付けたりする必要がなくなる。 As a corrosion detection method according to the present embodiment, a case where an optical fiber sensor is attached to the surface of a steel material will be illustrated. With this corrosion sensor, it is possible to detect the corrosion of the steel material itself. When the steel material is corroded, the optical fiber is stretched due to the volume expansion of the corrosion product. By detecting this elongation with a measuring instrument such as a data logger via an optical fiber sensor, it is possible to diagnose whether or not the steel material is in a corrosive environment, whether or not a corrosion factor has invaded, and whether or not the steel material is corroded. It becomes possible to do. As the steel material, the steel material used for the structure may be used, or a steel material may be separately prepared and a sensor may be installed. When a steel material is prepared separately and the sensor is installed, install it so that the sensor does not move or fall off in the peripheral area where the environment is the same as the measurement target. When the steel material used for the structure is used, it is not necessary to separately prepare or attach the steel material.

［実施形態１］
図１は、本発明に係る実施形態１を示す図である。実施形態１では、鋼材６０の平面に光ファイバセンサ６２を直接張り付ける態様を採る。例えば、図２に示すように、Ｈ鋼の側面に光ファイバセンサ６２を貼付し、保護用の塗料を塗布する。これにより、鋼材を加工することなく、直接鋼材に光ファイバセンサ６２を設けることが可能となる。その結果、鋼材腐食の早期発見が可能となる。また、腐食によるひずみを正確に検出することが可能となる。 [Embodiment 1]
FIG. 1 is a diagram showing Embodiment 1 according to the present invention. In the first embodiment, the optical fiber sensor 62 is directly attached to the flat surface of the steel material 60. For example, as shown in FIG. 2, an optical fiber sensor 62 is attached to the side surface of H steel, and a protective paint is applied. This makes it possible to provide the optical fiber sensor 62 directly on the steel material without processing the steel material. As a result, early detection of steel corrosion becomes possible. In addition, it becomes possible to accurately detect strain due to corrosion.

測定対象となる金属構造物、例えば、鋼橋やプラント設備、街路灯、土中埋設管、タンク、船舶などに保護塗料を塗布する場合、塗布前の金属材料の表面に、光ファイバセンサ６２を貼付する。光ファイバセンサ６２はＦＢＧセンサ等を用いることができる。鋼材６０に光ファイバセンサ６２を張付ける際には、直線状に配置すればよいが、屈曲していてもよい。光ファイバセンサ６２を鋼材６０に張り付ける際には、密着するように、好ましくは引張力が加わるように巻き付け、接着剤で両端を固定する。これにより、膨張側・収縮側両方のひずみが計測できるようになる。その後、保護塗料を塗布するまで風雨等により損傷しないように保護しておく。保護する材料としてフィルムやシール、塗料で溶解する材料で覆ってもよい。 When applying a protective paint to a metal structure to be measured, for example, a steel bridge, plant equipment, street lights, underground pipes, tanks, ships, etc., an optical fiber sensor 62 is applied to the surface of the metal material before application. Paste. As the optical fiber sensor 62, an FBG sensor or the like can be used. When the optical fiber sensor 62 is attached to the steel material 60, it may be arranged in a straight line, but it may be bent. When the optical fiber sensor 62 is attached to the steel material 60, it is wound so that it is in close contact with the steel material 60, preferably a tensile force is applied, and both ends are fixed with an adhesive. This makes it possible to measure strain on both the expansion side and the contraction side. After that, protect it from damage due to wind and rain until the protective paint is applied. As a protective material, it may be covered with a film, a seal, or a material that dissolves in paint.

光ファイバセンサの長さは、５ｍｍ〜５００ｍｍが好ましい。光ファイバセンサの長さが、５００ｍｍ以上では張付けの際の取扱いが困難であり、保護塗料の塗布時に損傷する恐れがある。また、光ファイバセンサの長さが、５ｍｍ以下では検知する腐食範囲が狭く、またひずみも小さくなることから検知精度が劣る。 The length of the optical fiber sensor is preferably 5 mm to 500 mm. If the length of the optical fiber sensor is 500 mm or more, it is difficult to handle when attaching, and there is a risk of damage when applying the protective paint. Further, when the length of the optical fiber sensor is 5 mm or less, the corrosion range to be detected is narrow and the strain is also small, so that the detection accuracy is inferior.

本実施形態では、光ファイバセンサおよびその端部を保護塗膜の外部に出して計測器に接続する。ここで、光ファイバセンサは細径であるため、光ファイバセンサを引き出した場合に生じる塗膜の欠陥を生じることなく、センサを設置することができる。あるいは、計測器や光ファイバに接続できるように取り出しておいてもよいし、常時監視できるように配線しておいてもよい。 In the present embodiment, the optical fiber sensor and its end are exposed to the outside of the protective coating film and connected to the measuring instrument. Here, since the optical fiber sensor has a small diameter, the sensor can be installed without causing defects in the coating film that occur when the optical fiber sensor is pulled out. Alternatively, it may be taken out so that it can be connected to a measuring instrument or an optical fiber, or it may be wired so that it can be constantly monitored.

［実施形態２］
図３は、実施形態２に係るセンサの使用例を示す図である。上述した実施形態１では鋼材の平面に光ファイバセンサを直接張り付けたが、本実施形態によれば、金属板６４に光ファイバセンサ６６を張付け、当該金属板６４を鋼材に張り付ける態様を採る。図４は、鋼材７０に光ファイバセンサ６６を有する金属板６４を張り付けて、保護塗膜７２を施した様子を示す図である。金属板（金属箔でもよい）６４の材質は、測定対象とする鋼材７０と同じものが好ましいが、早期検知のためにより錆びやすい材質の鉄や亜鉛にしてもよい。光ファイバセンサ６６を金属板６４に張り付ける際には、密着するように、好ましくは引張力が加わるように巻き付け、接着剤で両端を固定する。事前に室内で適切な引張力が加わるように光ファイバセンサ６６を金属板６４に張り付けておけば、設置したい鋼材に金属板６４を張付けるだけで腐食センサを設置できる。金属板６４の鋼材７０への張付けは接着剤を用いる。 [Embodiment 2]
FIG. 3 is a diagram showing a usage example of the sensor according to the second embodiment. In the above-described first embodiment, the optical fiber sensor is directly attached to the flat surface of the steel material, but according to the present embodiment, the optical fiber sensor 66 is attached to the metal plate 64, and the metal plate 64 is attached to the steel material. FIG. 4 is a diagram showing a state in which a metal plate 64 having an optical fiber sensor 66 is attached to a steel material 70 and a protective coating film 72 is applied. The material of the metal plate (which may be a metal foil) 64 is preferably the same as that of the steel material 70 to be measured, but iron or zinc, which is a material that is more easily rusted for early detection, may be used. When the optical fiber sensor 66 is attached to the metal plate 64, it is wound so that it is in close contact with the metal plate 64, preferably a tensile force is applied, and both ends are fixed with an adhesive. If the optical fiber sensor 66 is attached to the metal plate 64 in advance so that an appropriate tensile force is applied indoors, the corrosion sensor can be installed simply by attaching the metal plate 64 to the steel material to be installed. An adhesive is used to attach the metal plate 64 to the steel material 70.

また、金属板６４の厚さを変化させることによって、保護塗膜７２の厚さを変化させることができる。金属板６４の厚さが異なる複数種類のセンサを、複数個配置することによって、保護塗膜７２の厚さを正確に変化させ、段階的な劣化検出を実施することができる。この場合、同時に、現地の実環境での塗膜の保護性能を把握することも可能となる。また、保護塗膜７２の塗布回数を変化させてもよい。例えば、センサ張付け部のみ下塗りの塗装回数を減らすことで腐食因子の侵入を事前に検知することができる。 Further, the thickness of the protective coating film 72 can be changed by changing the thickness of the metal plate 64. By arranging a plurality of types of sensors having different thicknesses of the metal plate 64, the thickness of the protective coating film 72 can be accurately changed, and stepwise deterioration detection can be performed. In this case, at the same time, it is possible to grasp the protection performance of the coating film in the actual local environment. Further, the number of times the protective coating film 72 is applied may be changed. For example, the intrusion of corrosive factors can be detected in advance by reducing the number of times the undercoat is applied only to the sensor attachment portion.

このため、対象となる金属構造物の保護塗膜７２が劣化するよりも早期に、腐食の危険性を把握することが可能となる。さらに、金属板６４の厚みを段階的に変化させて、複数種類の厚さを持ったセンサを複数配置することにより、時系列的な劣化の進行を把握することができ、塗膜の耐久性の予測や計画的、効率的な塗膜の塗り変えなど、予防保全的な維持管理を可能にすることができる。 Therefore, it is possible to grasp the risk of corrosion earlier than the deterioration of the protective coating film 72 of the target metal structure. Furthermore, by gradually changing the thickness of the metal plate 64 and arranging a plurality of sensors having a plurality of types of thicknesses, it is possible to grasp the progress of deterioration over time, and the durability of the coating film can be grasped. It is possible to enable preventive maintenance such as prediction, systematic, and efficient repainting of the coating film.

本実施形態に係る金属板６４の厚さは、好ましくは０．０５ｍｍ以上０．５ｍｍ以下である。例えば、金属板６４の厚みを０．５ｍｍ以下としてセンサを構成すると、保護塗膜７２に埋設する場合に、特に好適となる。金属板６４（金属箔）の厚さは０．５ｍｍ以下であるので、フレキシブルで、化学工場プラントなどにおける配管やタンクや、球状のガスタンクなどの曲面形状にも対応可能である。また、塗布の際に段差となって障害となることもない。金属板６４（金属箔）の厚さは０．０５ｍｍより薄いと損傷する恐れがあり、また適切な引張力を与えることができなくなる。例えば、金属板６４（金属箔）の厚みを０．０５ｍｍ、０．１ｍｍ、０．１５ｍｍの３種類としてそれぞれセンサを構成し、これらの３種類のセンサを鋼構造物の表面に配置することにより、保護塗膜の劣化進行を段階的に検知することが可能となる。 The thickness of the metal plate 64 according to the present embodiment is preferably 0.05 mm or more and 0.5 mm or less. For example, if the thickness of the metal plate 64 is 0.5 mm or less and the sensor is configured, it is particularly suitable when it is embedded in the protective coating film 72. Since the thickness of the metal plate 64 (metal foil) is 0.5 mm or less, it is flexible and can be used for curved surfaces such as pipes and tanks in chemical factory plants and spherical gas tanks. In addition, it does not become a step and hinder the application. If the thickness of the metal plate 64 (metal foil) is thinner than 0.05 mm, it may be damaged, and an appropriate tensile force cannot be applied. For example, by configuring sensors with three types of metal plate 64 (metal foil) thicknesses of 0.05 mm, 0.1 mm, and 0.15 mm, and arranging these three types of sensors on the surface of a steel structure. , It becomes possible to detect the deterioration progress of the protective coating film step by step.

なお、金属板６４は金属構造物の保護塗膜７２の上から張付けてもよい。この場合、腐食センサに金属構造物と同様の保護塗膜を行なう。 The metal plate 64 may be attached from above the protective coating film 72 of the metal structure. In this case, the corrosion sensor is coated with a protective coating similar to that of a metal structure.

［実施形態３］
本実施形態は、上記の実施形態により光ファイバセンサを設置し、別途腐食を検知しないように防錆処理を施したダミーセンサと設置する様態である。すなわち、ダミーセンサを用いて腐食以外の要因で生じたひずみを検出し、光ファイバセンサで検出したひずみを補正することで、正確に腐食によるひずみを検知することができる。これにより、例えば、温度による鋼材の収縮ひずみなどの影響を除去することが可能となる。 [Embodiment 3]
In this embodiment, the optical fiber sensor is installed according to the above embodiment, and is installed as a dummy sensor that has been separately subjected to rust prevention treatment so as not to detect corrosion. That is, by detecting the strain generated by a factor other than corrosion using a dummy sensor and correcting the strain detected by the optical fiber sensor, it is possible to accurately detect the strain due to corrosion. This makes it possible to eliminate the influence of temperature, such as shrinkage strain of the steel material.

ダミーセンサの製造方法としては、鋼材や金属板の表面に光ファイバセンサを配置したのち、使用される保護塗料よりも中性化や劣化因子の侵入を防ぐ樹脂（例えばエポキシ樹脂）、塗料（例えばジンクリッチ系塗料）によるコーティングあるいはめっき、などで被覆し、内部の鋼材の腐食を防ぐ方法がある。本方法は、鋼材に直接光ファイバセンサを張付ける場合に適する。 As a method of manufacturing a dummy sensor, after arranging an optical fiber sensor on the surface of a steel material or a metal plate, a resin (for example, epoxy resin) or a paint (for example, an epoxy resin) that prevents neutralization or invasion of deterioration factors rather than the protective paint used is used. There is a method of coating or plating with a zinc rich paint) to prevent corrosion of the steel material inside. This method is suitable for attaching the optical fiber sensor directly to the steel material.

また、ダミーセンサの製造方法としては、チタンや貴金属等の腐食しない金属板を鋼材に張付けてから、当該金属板に光ファイバセンサを張り付ける。本方法は、金属箔に光ファイバセンサを張付ける場合に適する。 Further, as a method of manufacturing a dummy sensor, a non-corrosive metal plate such as titanium or a noble metal is attached to a steel material, and then an optical fiber sensor is attached to the metal plate. This method is suitable for attaching an optical fiber sensor to a metal foil.

また、鋼管、丸鋼の内部など腐食が生じない部分が存在する場合には、当該部位に光ファイバセンサを設置し、ダミーセンサとしてもよい。 Further, when there is a portion where corrosion does not occur, such as inside a steel pipe or round steel, an optical fiber sensor may be installed in the portion to serve as a dummy sensor.

［実施形態４］
上記の実施形態は、対象とする構造物の鋼材に光ファイバセンサを設置するものであったが、本実施形態は、別途光ファイバセンサが貼り付けられた鋼材を腐食センサとして設置する様態である。すなわち、上記実施形態の鋼材を小型の鋼材に換えたものであり、例えば、対象物と同じ材質の小型の鉄棒や鉄板に光ファイバセンサを貼り付け、保護塗料を塗布したものである。取り付け方法は、上記実施形態と同様である。本実施形態で製造したセンサは、測定対象と環境が同一である対象物の周辺部に移動したり脱落したりしないように処置を講じて設置するのみである。本実施形態のセンサは、現場で製造することはなく精密に室内で製造して測定箇所に運搬すれば使用可能となる。したがって、現場における施工も通常のように実施され、手間が増えることはなく、構造物にセンサを貼り付けるなど手を加えることもない。また、測定が容易な場所に設置することもできる。 [Embodiment 4]
In the above embodiment, the optical fiber sensor is installed on the steel material of the target structure, but in the present embodiment, the steel material to which the optical fiber sensor is separately attached is installed as a corrosion sensor. .. That is, the steel material of the above embodiment is replaced with a small steel material, for example, an optical fiber sensor is attached to a small iron rod or iron plate of the same material as the object, and a protective paint is applied. The mounting method is the same as that of the above embodiment. The sensor manufactured in the present embodiment is only installed by taking measures so that the sensor does not move or fall off to the peripheral portion of the object whose environment is the same as that of the measurement object. The sensor of this embodiment can be used if it is precisely manufactured indoors and transported to a measurement location without being manufactured on-site. Therefore, the on-site construction is carried out as usual, the labor is not increased, and no modification such as attaching a sensor to the structure is required. It can also be installed in a place where measurement is easy.

［検証例］
図５は、金属の腐食により光ファイバセンサがひずみを検知するかを検証するために用いた試験体を示す図である。図５に示すように、試験体４０は、棒鋼５０に光ファイバセンサ５１を巻き付けて、モルタル等のセメント硬化体５２で被覆することにより構成されている。試験体４０に対して、上下方向のかぶりが２０ｍｍであり、左右方向のかぶりが１０ｍｍである。図５では、棒鋼５０に対して光ファイバセンサ５１を１巻とした例を示したが、以下、３巻とする場合も併せて検証する。次に、試験体４０の具体的検証例を示す。 [Verification example]
FIG. 5 is a diagram showing a test piece used to verify whether the optical fiber sensor detects strain due to metal corrosion. As shown in FIG. 5, the test body 40 is configured by winding an optical fiber sensor 51 around a steel bar 50 and coating it with a cement hardened body 52 such as mortar. With respect to the test body 40, the cover in the vertical direction is 20 mm, and the cover in the left-right direction is 10 mm. FIG. 5 shows an example in which the optical fiber sensor 51 has one roll for the steel bar 50, but the case where the optical fiber sensor 51 has three rolls will also be verified below. Next, a specific verification example of the test body 40 will be shown.

みがき棒鋼は、ＪＩＳＧ３１０８ＳＧＤ３Ｍを使用した。みがき棒鋼に対する光ファイバの巻き方は、一定の張力下、例えば、巻き付け時に多少の引張ひずみが出ていることを確認した上で、巻き付け作業を行ない、端部をＣＮ（東京測器製）で固定した。光ファイバセンサ（ＦＢＧセンサ）は、表２に示す仕様のものを用いた。また、ダミーセンサによるひずみ挙動の差異で腐食検知を行なうのが好ましく、被覆モルタルの体積変化や含水率の影響がひずみに表れることが予想されるため、試験体の仕様に応じて、ダミーの試験体を作製した。 JIS G 3108 SGD3M was used as the polishing steel bar. To wind the optical fiber around the polished steel bar, under a certain tension, for example, after confirming that some tensile strain is generated during winding, perform the winding work and use CN (manufactured by Tokyo Sokki) at the end. Fixed. As the optical fiber sensor (FBG sensor), the one having the specifications shown in Table 2 was used. In addition, it is preferable to detect corrosion by the difference in strain behavior by the dummy sensor, and it is expected that the influence of the volume change and water content of the coated mortar will appear in the strain. Therefore, a dummy test is performed according to the specifications of the test piece. The body was made.

次に、被覆モルタルについて説明する。モルタルの使用材料は、次の表に示す通りである。

Next, the coated mortar will be described. The materials used for mortar are as shown in the following table.

次に、モルタルの配合は、次の表に示す通りである。

なお、上記の表中、「Ｂ」とは、「Ｃ」と「Ｌ」とを混合したものである。 Next, the composition of the mortar is as shown in the following table.

In the above table, "B" is a mixture of "C" and "L".

［モルタルの練混ぜ方法］
試験体に用いるモルタルは、“株式会社丸東製作所社製のモルタルミキサ（2L練）”を用いて練混ぜを行なった。練混ぜ手順は、以下の通りである。なお、モルタルの練混ぜは、２０±２℃、湿度５０％以上の恒温恒湿室にて行なった。 [Mortar mixing method]
The mortar used for the test body was kneaded using "Mortar mixer (2L kneading) manufactured by Maruto Seisakusho Co., Ltd.". The kneading procedure is as follows. The mortar was kneaded in a constant temperature and humidity chamber at 20 ± 2 ° C. and a humidity of 50% or more.

塩ビ製型枠（内径φ４０ｍｍ×高さ５０ｍｍ、または内径φ４０ｍｍ×高さ６５ｍｍ）にモルタルを打込み、その中に光ファイバを巻いた棒鋼を中央部に入れ、その後、同じ恒温恒湿室で３時間養生後、２０℃湿度９５％以上で７日間養生し、脱型した。 Mortar is driven into a PVC mold (inner diameter φ40 mm x height 50 mm, or inner diameter φ40 mm x height 65 mm), and a steel bar wrapped with an optical fiber is placed in the center, and then in the same constant temperature and humidity chamber for 3 hours. After curing, it was cured at 20 ° C. and a humidity of 95% or more for 7 days, and then demolded.

試験体４０を腐食環境下（温度４０℃下で、ＮａＣｌ：１０％水溶液に浸漬１日、湿度６０％乾燥３日、再度ＮａＣｌ：１０％水溶液に浸漬１日、以降は湿度６０％乾燥）におき、計測機器（株式会社渡辺製作所製）により波長の変化を計測した。ＮａＣｌ：１０％水溶液の浸漬は、光ファイバ引き出し部からＮａＣｌ水溶液の侵入がないように、試験体の下端から３０ｍｍ（３巻きの場合は、試験体の下端から４５ｍｍ）の部分までを浸漬させた。また、ダミー試験体は、ここでは実験上腐食しない棒鋼を用いずに腐食センサと同じ試験体を用いており、ＮａＣｌ水溶液を用いる代わりに腐食することのない純水に浸漬した。 The test piece 40 is placed in a corrosive environment (immersed in a NaCl: 10% aqueous solution for 1 day, dried at a humidity of 60% for 3 days, immersed in a NaCl: 10% aqueous solution again for 1 day, and then dried at a humidity of 60%). The change in wavelength was measured with a measuring device (manufactured by Watanabe Seisakusho Co., Ltd.). In the immersion of the NaCl: 10% aqueous solution, the portion 30 mm from the lower end of the test piece (45 mm from the lower end of the test piece in the case of 3 rolls) was immersed so that the NaCl aqueous solution did not enter from the optical fiber extraction part. .. Further, as the dummy test piece, the same test piece as the corrosion sensor was used here without using a steel bar that does not corrode experimentally, and instead of using an aqueous NaCl solution, the dummy test piece was immersed in pure water that does not corrode.

以下の式により、波長からひずみに変換し、腐食によるひずみの変化を確認した。

ここで、ε：ひずみ（μ）、λ：測定時の波長（ｎｍ）、λ^*：初期波長（ｎｍ）である。 The wavelength was converted to strain by the following formula, and the change in strain due to corrosion was confirmed.

Here, ε: strain (μ), λ: wavelength at the time of measurement (nm), λ ^* : initial wavelength (nm).

図６は、腐食環境下における経過時間とひずみとの関係を示すグラフである。図６に示す１巻きとした検証例では、１日と４日に塩水や水に浸漬したため、温度変化やモルタルの吸水などで一時的にひずみが変化したが、ダミー試験体も同じ様に変化したため、腐食によるものではない。１６日に試験体とダミー試験体のひずみ量が乖離した。そこで、試験体の被覆モルタルを除去したところ、棒鋼が腐食していることが確認された。 FIG. 6 is a graph showing the relationship between elapsed time and strain in a corrosive environment. In the verification example with one roll shown in FIG. 6, since the strain was immersed in salt water or water on the 1st and 4th, the strain temporarily changed due to temperature changes and water absorption of the mortar, but the dummy specimen also changed in the same manner. Therefore, it is not due to corrosion. On the 16th, the strain amounts of the test body and the dummy test body deviated from each other. Therefore, when the coated mortar of the test piece was removed, it was confirmed that the steel bar was corroded.

図７に示す３巻きとした検証例では、温度が一定になった後に計測を開始し、腐食後も計測を継続した例である。測定日数４５日に腐食ひび割れが発生した。ひび割れが発生するまで、継続的に腐食による膨張を捉えることが可能であることが証明された。 In the verification example with three turns shown in FIG. 7, the measurement was started after the temperature became constant, and the measurement was continued even after the corrosion. Corrosion cracks occurred on the 45th measurement day. It has been proved that it is possible to continuously capture the expansion due to corrosion until cracks occur.

［検証例２］
腐食の状況に応じてひずみが増加するかどうかを確認するため、鋼材に光ファイバを巻き付けた大気中の場合について、腐食状況の確認と光ファイバによるひずみ計測を行なった。図８に示すように、試験体はφ２０ｍｍ棒鋼５０に、中心部の測定領域高さ２５ｍｍの範囲で光ファイバセンサ５１を１巻とした。図９は、測定結果を示す図である。測定２日目までは２０℃大気中であるため、丸１に示すように、腐食はほとんどなく、その直後にファイバ１巻の試験体中央部に塩水を塗布した。その後急激にひずみが増大し、丸２において目視による判定で腐食範囲が１０％であり、丸３において目視による判定で腐食範囲が３５％となった。以上の結果より、腐食の程度に対応してひずみは増大していることが分かる。 [Verification example 2]
In order to confirm whether the strain increases according to the corrosion condition, the corrosion condition was confirmed and the strain was measured by the optical fiber in the case where the optical fiber was wound around the steel material in the atmosphere. As shown in FIG. 8, the test piece was formed by winding an optical fiber sensor 51 on a φ20 mm steel bar 50 within a measurement region height of 25 mm at the center. FIG. 9 is a diagram showing the measurement results. Since the temperature was 20 ° C. in the air until the second day of measurement, as shown in circle 1, there was almost no corrosion, and immediately after that, salt water was applied to the central part of the test piece of one fiber roll. After that, the strain increased sharply, and in circle 2, the corrosion range was 10% by visual judgment, and in circle 3, the corrosion range was 35% by visual judgment. From the above results, it can be seen that the strain increases according to the degree of corrosion.

これにより、局所的に保護塗料の劣化進行状況を検出することが可能となる。その結果、効果的で、かつ効率的な塗装サイクルを設定することが可能となり、ライフサイクルコストの削減を計ることが可能となる。 This makes it possible to locally detect the deterioration progress of the protective coating material. As a result, it is possible to set an effective and efficient coating cycle, and it is possible to reduce the life cycle cost.

４０試験体
５０棒鋼
５１光ファイバセンサ
５２セメント硬化体（モルタル）
６０鋼材
６２光ファイバセンサ
６４金属板（金属箔）
６６光ファイバセンサ
７０鋼材
７２保護塗膜 40 Specimen 50 Bar Steel 51 Optical Fiber Sensor 52 Cement Hardened Body (Mortar)
60 Steel 62 Optical fiber sensor 64 Metal plate (metal foil)
66 Optical fiber sensor 70 Steel material 72 Protective coating

Claims

It is a deterioration detection method that detects the deterioration progress of the protective paint applied to the steel material.
Before attaching the optical fiber sensor to the surface of the steel material, a dummy sensor with a rust preventive coating attached to the surface of the steel material is provided, and the dummy sensor is used to detect the strain generated by factors other than corrosion, and the detected strain is detected. Steps to correct and
The process of attaching the optical fiber sensor directly to the surface of the steel material,
A step of applying a protective paint to the steel material to which the optical fiber sensor is attached so as to cover the optical fiber sensor, and
It includes at least a step of connecting a measuring instrument to the optical fiber sensor and measuring strain based on a characteristic change of a light wave propagating in the optical fiber sensor caused by volume expansion of a corrosion product of the steel material.
A deterioration detection method characterized by detecting the deterioration progress of the protective coating material applied to the steel material based on the measured strain.

It is a deterioration detection method that detects the deterioration progress of the protective paint applied to the steel material.
The process of attaching the optical fiber sensor directly to the surface of the steel material,
A step of applying a protective paint to the steel material to which the optical fiber sensor is attached so as to cover the optical fiber sensor, and
A step of connecting a measuring instrument to the optical fiber sensor and measuring strain based on a change in the characteristics of a light wave propagating in the optical fiber sensor caused by volume expansion of a corrosion product of the steel material.
A dummy sensor that has been subjected to rust prevention treatment that does not allow corrosion factors to penetrate is provided on the surface of the attached optical fiber sensor, and the dummy sensor is used to detect strain caused by factors other than corrosion, and the detected strain is detected. Including at least the steps to correct
A deterioration detection method characterized by detecting the deterioration progress of the protective coating material applied to the steel material based on the measured strain.

It is a deterioration detection method that detects the deterioration progress of the protective paint applied to the steel material.
Before attaching the optical fiber sensor to the surface of the metal plate, a dummy sensor having an anticorrosive coating attached to the surface of the metal plate was provided, and the dummy sensor was used to detect the strain generated by a factor other than corrosion, and the detection was performed. Steps to correct distortion and
The process of attaching the optical fiber sensor to the surface of the metal plate and
The process of directly attaching the metal plate to which the optical fiber sensor is attached to the surface of the steel material, and
A process of applying a protective paint to the steel material to which the metal plate is attached so that the optical fiber sensor is covered.
It includes at least a step of connecting a measuring instrument to the optical fiber sensor and measuring strain based on a characteristic change of a light wave propagating in the optical fiber sensor caused by volume expansion of a corrosion product of the steel material.
A deterioration detection method characterized by detecting the deterioration progress of the protective coating material applied to the steel material based on the measured strain .

It is a deterioration detection method that detects the deterioration progress of the protective paint applied to the steel material.
The process of attaching the optical fiber sensor to the surface of the metal plate and
The process of directly attaching the metal plate to which the optical fiber sensor is attached to the surface of the steel material, and
A process of applying a protective paint to the steel material to which the metal plate is attached so that the optical fiber sensor is covered.
A step of connecting a measuring instrument to the optical fiber sensor and measuring strain based on a change in the characteristics of a light wave propagating in the optical fiber sensor caused by volume expansion of a corrosion product of the steel material.
A dummy sensor that has been subjected to rust prevention treatment that does not allow corrosion factors to penetrate is provided on the surface of the attached optical fiber sensor, and the dummy sensor is used to detect strain caused by factors other than corrosion, and the detected strain is detected. at least look at including a step of correcting, the,
A deterioration detection method characterized by detecting the deterioration progress of the protective coating material applied to the steel material based on the measured strain .

It is a deterioration detection method that detects the deterioration progress of the protective paint applied to the steel material.
The process of attaching the optical fiber sensor to the surface of the metal plate and
The process of directly attaching a plurality of metal plates having different thicknesses to which the optical fiber sensor is attached to the surface of the steel material, and
A process of applying a protective paint to the steel material to which the metal plate is attached so that the optical fiber sensor is covered.
It includes at least a step of connecting a measuring instrument to the optical fiber sensor and measuring strain based on a characteristic change of a light wave propagating in the optical fiber sensor caused by volume expansion of a corrosion product of the steel material.
A deterioration detection method characterized by detecting the deterioration progress of the protective coating material applied to the steel material based on the measured strain.