JPH09196876A - Detecting method for corroded spot of steel material in concrete - Google Patents
Detecting method for corroded spot of steel material in concreteInfo
- Publication number
- JPH09196876A JPH09196876A JP8005041A JP504196A JPH09196876A JP H09196876 A JPH09196876 A JP H09196876A JP 8005041 A JP8005041 A JP 8005041A JP 504196 A JP504196 A JP 504196A JP H09196876 A JPH09196876 A JP H09196876A
- Authority
- JP
- Japan
- Prior art keywords
- concrete
- steel material
- resistance
- impedance
- measurement
- 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.)
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Links
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- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、コンクリート中の
鋼材の腐食箇所検出方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a corrosion point of a steel material in concrete.
【０００２】[0002]
【従来の技術とその課題】コンクリートは、一般には、
種々の環境に対する抵抗力が強く、また、強アルカリ性
であるので、その内部にある鋼材は、鋼材表面に不動態
被膜を形成して腐食から保護され、そのために、コンク
リート構造物は耐久性のある永久構造物であると考えら
れてきた。[Prior art and its problems] Concrete is generally
Due to its strong resistance to various environments and its strong alkalinity, the steel material inside it is protected from corrosion by forming a passive film on the steel surface, which makes the concrete structure durable. It has been considered to be a permanent structure.
【０００３】しかしながら、この永久構造物と考えられ
てきたコンクリート構造物も、空気中の炭酸ガスにより
コンクリートのｐＨ値が低下する中性化や、塩素イオン
のコンクリート中への浸透によりコンクリート中の鋼材
が腐食する塩害などの原因によりコンクリート中の鋼材
が腐食し、コンクリート構造物の強度を保持するという
機能を失い構造物としての寿命に疑問がなげかけられる
ようになってきた。However, the concrete structure which has been considered to be a permanent structure is also a steel material in the concrete due to neutralization in which the pH value of the concrete is lowered by carbon dioxide gas in the air and permeation of chlorine ions into the concrete. Steel materials in concrete are corroded due to salt damage, etc., and the function of maintaining the strength of concrete structures is lost, leading to doubts about the life of the structures.
【０００４】このような劣化したコンクリート構造物中
の鋼材の腐食状況を検査する方法として、従来は、鋼材
のかぶりコンクリートをはつり、コンクリート中の鋼材
を露出することによってその鋼材の腐食状況を確認する
目視による検査方法が行われてきた。Conventionally, as a method for inspecting the corrosion state of steel material in such a deteriorated concrete structure, the corrosion state of the steel material is confirmed by mounting a steel-covered concrete and exposing the steel material in the concrete. Visual inspection methods have been used.
【０００５】このコンクリートのはつり作業は、作業環
境を悪化させ、安全性からの問題があり、また、コンク
リート構造物の強度を低下させるもので、はつり作業が
ない非破壊による検査方法、例えば、自然電位法、表面
電位差法、電気抵抗法、分極抵抗法、及びＡＣインピー
ダンス法等が提案された〔ＡＳＴＭ(American Society
for Testing Materials)Ｃ８７６、特開昭59−217147号
公報、特開昭63−163266号公報、鉄筋腐食の診断1993年
５月28日 森北出版株式会社発行〕。This concrete chipping work deteriorates the work environment and poses a problem from the safety, and also reduces the strength of the concrete structure. For example, a non-destructive inspection method without chipping work, for example, natural Potential method, surface potential difference method, electric resistance method, polarization resistance method, AC impedance method, etc. have been proposed [ASTM (American Society
for Testing Materials) C876, JP-A-59-217147, JP-A-63-163266, and diagnosis of rebar corrosion May 28, 1993, issued by Morikita Publishing Co., Ltd.].
【０００６】自然電位法は、コンクリート中の鋼材に導
線を接続し、銅−硫酸銅電極などを使用してコンクリー
ト表面での測定によりコンクリート内部の鋼材表面の電
気化学的活性度を測定する方法であるが、この方法で
は、コンクリートの含水量等の影響を受け、測定誤差が
大きく、鋼材の腐食を評価する方法としては不充分であ
るという課題があった。The self-potential method is a method in which a conductor wire is connected to a steel material in concrete and the electrochemical activity of the steel material surface inside the concrete is measured by measuring on the concrete surface using a copper-copper sulfate electrode or the like. However, this method has a problem that it is unsatisfactory as a method for evaluating corrosion of steel materials due to a large measurement error due to the influence of the water content of concrete and the like.
【０００７】表面電位差法は、自然電位法の応用であ
り、２個の照合電極を用い、コンクリート表面での測定
により自然電位の電位勾配を求める方法であるが、この
方法では、鋼材に導線を接続する必要はないものの、鋼
材の腐食の程度が推定できる自然電位の絶対値が求める
ことができないという課題があった。The surface potential difference method is an application of the natural potential method and is a method of obtaining the potential gradient of the natural potential by measuring on the concrete surface by using two reference electrodes. In this method, a conductor is attached to a steel material. Although it is not necessary to connect it, there was a problem that the absolute value of the natural potential that can estimate the degree of corrosion of steel could not be obtained.
【０００８】電気抵抗法は、コンクリートの電気抵抗を
測定することで、コンクリート中の腐食因子の浸入の容
易さや浸入状況を知る方法であるが、鋼材の腐食の可能
性は推定できても、鋼材の腐食状況を知るには不十分で
あるという課題があった。The electrical resistance method is a method of measuring the electrical resistance of concrete so as to know the easiness of infiltration of a corrosion factor into concrete and the infiltration situation, but even if the possibility of corrosion of steel materials can be estimated, However, there was a problem that it was insufficient to know the corrosion status of.
【０００９】分極抵抗法は、コンクリート中の鋼材の一
部に導線を接続し、コンクリート表面からコンクリート
内部の鋼材に対して直流電流を流し、鋼材表面の分極抵
抗を測定する方法であるが、この方法では、その測定が
厳密でかつ、測定に時間がかかるため、現実のコンクリ
ート構造物への適用は難しいという課題があった。The polarization resistance method is a method in which a conductive wire is connected to a part of steel material in concrete and a direct current is applied from the concrete surface to the steel material inside the concrete to measure the polarization resistance of the steel material surface. In the method, there is a problem that it is difficult to apply it to an actual concrete structure because the measurement is strict and the measurement takes time.
【００１０】ＡＣインピーダンス法は、コンクリート中
の鋼材に導線を接続し、コンクリート表面から鋼材に、
１０〜２０ｍＶの電圧で０．０１Ｈｚ〜１００ＫＨｚの
交流電流を流し、分極抵抗を測定し、鋼材の腐食の程度
の推定を行うものである。ＡＣインピーダンス法は、そ
の信頼性の高さと測定の簡便さから、最近注目をあびて
おり、試験室や現場での分極抵抗やコンクリート電気抵
抗率の測定に多用されるようになってきた。In the AC impedance method, a conductor wire is connected to a steel material in concrete, and the concrete surface is connected to the steel material.
An alternating current of 0.01 Hz to 100 KHz is applied at a voltage of 10 to 20 mV, polarization resistance is measured, and the degree of corrosion of the steel material is estimated. The AC impedance method has recently attracted attention due to its high reliability and ease of measurement, and has come to be used frequently for measuring polarization resistance and concrete electrical resistivity in a test room or in the field.
【００１１】しかしながらこのＡＣインピーダンス法で
は、コンクリート中の鋼材への導線の接続が必要であ
り、この接続は、試験室での試験体を用いた測定では、
試験体作成の際、あらかじめ鋼材を露出させておくか、
導線を接続しておくことが必要であり、現場でのコンク
リート構造物の測定では、コンクリート内部の鋼材が露
出している場合を除いて、鋼材を露出させるため、鋼材
までのコンクリートのはつり作業やコアリング作業が必
要となるという課題があった。However, in this AC impedance method, it is necessary to connect a conductive wire to a steel material in concrete, and this connection is measured by a test body in a test room.
When the test piece is created, expose the steel material in advance, or
It is necessary to connect the conductors, and when measuring concrete structures on-site, except when the steel material inside the concrete is exposed, the steel material is exposed. There was a problem that coring work was required.
【００１２】つまり、ＡＣインピーダンス法は、非破壊
による検査の方法の１つとは言いながら導線接続のため
の破壊作業が必要であり、その労力や破壊することによ
る構造物の信頼性が低下する可能性があるという課題が
あった。本発明者らは、前記課題を解決すべく種々検討
した結果、特定の方法採用することにより、前記課題が
解決し得ることを知見し、本発明を完成するに至った。That is, although the AC impedance method is one of the non-destructive inspection methods, it requires a destructive work for connecting conductors, which may reduce the labor and reliability of the structure due to the destructive work. There was a problem that there is a nature. As a result of various studies to solve the above problems, the present inventors have found that the above problems can be solved by adopting a specific method, and have completed the present invention.
【００１３】[0013]
【課題を解決するための手段】即ち、本発明は、電極を
備えた２個以上の鋼材腐食検出端をコンクリート表面に
接触させ、該電極間に交流電流を流すことを特徴とする
コンクリート中の鋼材の腐食箇所検出方法であり、コン
クリート中の２箇所以上の鋼材の分極抵抗又はコンクリ
ート電気抵抗率を測定することを特徴とする該コンクリ
ート中の鋼材の腐食箇所検出方法である。That is, according to the present invention, two or more steel corrosion detecting ends provided with electrodes are brought into contact with a concrete surface, and an alternating current is passed between the electrodes. A method for detecting a corrosion point of a steel material, which is a method for detecting a corrosion point of a steel material in the concrete, characterized by measuring polarization resistance or concrete electrical resistivity of two or more steel materials in the concrete.
【００１４】[0014]
【発明の実施の形態】以下、本発明を詳細に説明する。
本発明は、コンクリート中の被測定鋼材近傍のコンクリ
ート表面に、電極を備えた鋼材腐食検出端（以下本検出
端という）を少なくとも２個接触させ、交流電流を流す
ＡＣインピーダンス法により測定を実施するものであ
る。BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The present invention performs measurement by an AC impedance method in which at least two steel material corrosion detection ends (hereinafter referred to as main detection ends) equipped with electrodes are brought into contact with the concrete surface in the vicinity of the steel material to be measured in concrete, and an alternating current is passed. It is a thing.
【００１５】本発明で使用する本検出端は、電極を備
え、コンクリート表面に交流電流が流れやすくなってい
るものであれば特に限定されるものではないが、電極を
備え、塩化カリウムや水酸化カルシウムなどの電解質溶
液を含浸する脱脂綿やスポンジなどの保水材が、コンク
リート表面に接触できるようになっているものが、作業
性の面から好ましい。The present detection end used in the present invention is not particularly limited as long as it is provided with an electrode so that an alternating current can easily flow on the concrete surface. A water-retaining material such as absorbent cotton or sponge impregnated with an electrolyte solution such as calcium that can contact the concrete surface is preferable from the viewpoint of workability.
【００１６】また、保水材の乾燥を防ぐために、電解質
溶液を蓄え、保水材へ常に電解質溶液を供給できる容器
を使用することはより有効である。本検出端の形状や大
きさは、コンクリート表面との接触面積が０．５ｃｍ2
以上確保できれば特に限定されるものではない。また、
印加電圧を自然電位を基準として測定する場合には、鉛
電極、銀−塩化銀電極、及び飽和カロメル電極等の照合
電極を備えたものを使用することが望ましいが、自然電
位を基準としない場合には照合電極を使用しなくても、
電極間の電位差を測定することで計測が可能である。Further, in order to prevent the water retaining material from drying, it is more effective to use a container which can store the electrolyte solution and can always supply the electrolyte solution to the water retaining material. As for the shape and size of this detection end, the contact area with the concrete surface is 0.5 cm 2
There is no particular limitation as long as the above can be secured. Also,
When measuring the applied voltage with reference to the natural potential, it is desirable to use one equipped with a reference electrode such as a lead electrode, a silver-silver chloride electrode, and a saturated calomel electrode. Without using a reference electrode,
Measurement is possible by measuring the potential difference between the electrodes.
【００１７】本発明で使用する電極としては電流が充分
に流れれば特に限定されるものではないが、耐久性等の
面から、白金やチタンなどの材料で加工されたものが好
ましい。また、電極形状は特に限定されるものではない
が、電気化学的に安定な線状や面状の材料の使用が好ま
しく、電流の流れを良好とする目的から、電極の表面積
は１ｍｍ2 以上が好ましい。２個以上の本検出端を用い
て、コンクリート中の鋼材腐食状況を検査する際、本検
出端間隔は、５ｃｍ〜５０ｍが好ましく、２０ｃｍ〜３
０ｍがより好ましい。この間隔が５ｃｍ未満では、本来
コンクリート表面と鋼材との間に流すべき電流が鋼材を
通過せず、コンクリート表面又はコンクリート表層中を
バイパスして流れてしまう場合があり、間隔が５０ｍを
越える場合は、鋼材の電気抵抗の影響が測定値に誤差と
して含まれたり、鋼材相互の接触抵抗が大きく、測定が
不可能になる場合がある。The electrode used in the present invention is not particularly limited as long as a sufficient current flows, but from the viewpoint of durability and the like, an electrode processed with a material such as platinum or titanium is preferable. The shape of the electrode is not particularly limited, but it is preferable to use a linear or planar material that is electrochemically stable, and the surface area of the electrode should be 1 mm 2 or more for the purpose of improving current flow. preferable. When inspecting a steel material corrosion state in concrete using two or more main detecting ends, the main detecting end interval is preferably 5 cm to 50 m, and 20 cm to 3
0 m is more preferable. If the distance is less than 5 cm, the electric current that should originally flow between the concrete surface and the steel material may not pass through the steel material and may flow by-passing through the concrete surface or the concrete surface layer. If the distance exceeds 50 m, In some cases, the influence of the electric resistance of steel materials is included in the measured value as an error, or the mutual contact resistance between steel materials is large, making measurement impossible.
【００１８】次にポテンショスタット、ガルバノスタッ
トについて説明する。検出端は導線により、ポテンショ
スタット、あるいは、ガルバノスタットに接続される。
ポテンショスタットは、電圧制御による通電を行う装
置、ガルバノスタットは電流制御による通電を行う装置
として一般に用いられている装置であるが、本発明にこ
れらの装置を使用する際には、交流出力電圧、あるい
は、交流検出電圧の最大値が５０ｍＶ程度、交流出力電
流、あるいは、交流検出電流の最大値が１００ｍＡ程度
の能力があれば使用可能である。照合電極を使用する場
合には、４電極方式、つまり、電流の供給端子２点、電
圧検出端子２点を備えた装置を使用することが望まし
い。Next, the potentiostat and galvanostat will be described. The detection end is connected to a potentiostat or a galvanostat by a conductive wire.
The potentiostat is a device that conducts current by voltage control, and the galvanostat is a device that is generally used as a device that conducts current by current control.When using these devices in the present invention, an AC output voltage, Alternatively, it can be used as long as the maximum value of the AC detection voltage is about 50 mV and the capacity of the AC output current or the maximum value of the AC detection current is about 100 mA. When using the reference electrode, it is desirable to use a four-electrode system, that is, an apparatus having two current supply terminals and two voltage detection terminals.
【００１９】次に周波数アナライザーについて説明す
る。ポテンショスタット、あるいは、ガルバノスタット
は、周波数アナライザーにより制御される。周波数アナ
ライザーは、ポテンショスタット、あるいは、ガルバノ
スタットに出力命令を与える装置として一般に用いられ
ている装置であるが、その制御周波数が１Ｈｚ以下から
１００Ｈｚ以上の正弦波、あるいは、方形波等の交流出
力が出来れば、いかようなものも使用可能である。Next, the frequency analyzer will be described. The potentiostat or galvanostat is controlled by the frequency analyzer. A frequency analyzer is a device that is generally used as a device that gives an output command to a potentiostat or a galvanostat, but its control frequency is a sine wave from 1 Hz or less to 100 Hz or more, or an AC output such as a square wave. Anything can be used if possible.
【００２０】次に、測定方法について説明する。測定に
際しては、コンクリート表面の電気的状態を安定させる
目的から、測定の前にコンクリート面を水道水や水酸化
カルシウム溶液で湿潤状態にしておくことが好ましい。
この状態で全ての装置の接続を行い、検出端をコンクリ
ート表面に接触させた後、検出極の中の電極相互に１〜
５０ｍＶの交流電圧を印加する。従来の鉄筋への導線接
続法によるＡＣインピーダンス法に比べ、本発明で測定
端を２個使用する場合には、電流の経路が２倍となって
しまう為、通常の約２倍の電圧の印加を必要とする。周
波数を少なくとも２種類使用することで測定は可能であ
る。Next, the measuring method will be described. At the time of measurement, it is preferable to wet the concrete surface with tap water or a calcium hydroxide solution before the measurement for the purpose of stabilizing the electrical state of the concrete surface.
After connecting all the devices in this state and bringing the detection end into contact with the concrete surface,
An alternating voltage of 50 mV is applied. In the case of using two measuring ends in the present invention, the current path is doubled as compared with the conventional AC impedance method by connecting a conductor to a reinforcing bar, so that a voltage of about twice the normal voltage is applied. Need. Measurement is possible by using at least two types of frequencies.
【００２１】周波数の与え方の一例を述べる。まず、低
周波ＨL を用いて、電圧ＶL を与え、電流ＩL を流した
場合は、図１の等価回路において、電気二重層容量がイ
ンピーダンスとして大きな値となる為、Ｒp とＲs がイ
ンピーダンスとして作用し、ＩL は、ほぼの経路で流
れる。次に高周波ＨH を用いて電圧ＶH を与え、電流Ｉ
H を流した場合は、電気二重層容量がインピーダンスと
して小さな値となる為、Ｒs のみがインピーダンスとし
て作用し、ＩH は、ほぼの経路で流れる。非常に小さ
なＨL 、非常に大きなＨH を用いた場合、図１でコンク
リート電気抵抗Ｒs 〔Ω〕は約ＥH ／ＩH として得るこ
とが出来、分極抵抗Ｒp 〔Ω〕は約ＥL ／ＩL −ＥH ／
ＩH として求めることが出来る。この結果に鉄筋径、か
ぶり厚さを考慮することによって、コンクリート電気抵
抗率〔Ω・ｃｍ〕、分極抵抗〔Ω・ｃｍ2 〕への単位の
変換が出来る。電気二重層容量によるインピーダンス
は、１／（２πｆＣ）、（ここで、ｆ＝周波数、Ｃ＝電
気二重層容量）で与えられる為、低周波とすれば、出来
るだけ低い周波数を使用した方が測定の精度は向上する
が、周波数が低い程、測定時間を長く必要としてしまう
為、実用的には、０．０１〜１Ｈｚ程度を用いることが
望ましい。高周波としては、出来るだけ次数の高い周波
数を使用する程、測定精度は向上するが、周波数が高す
ぎると、電波による漏れが発生してしまう為、５〜１０
０ｋＨｚが実用的である。An example of how to give a frequency will be described. First, when the voltage VL is applied by using the low frequency HL and the current IL is passed, the electric double layer capacitance has a large value as impedance in the equivalent circuit of FIG. 1, so Rp and Rs act as impedance. , IL flow almost along the path. Next, the high frequency HH is used to apply the voltage VH, and the current I
When H 2 is flown, the electric double layer capacitance has a small value as impedance, so that only Rs acts as impedance and IH flows through almost the same path. When very small HL and very large HH are used, the concrete electric resistance Rs [Ω] can be obtained as about EH / IH and the polarization resistance Rp [Ω] is about EL / IL-EH / in FIG.
It can be calculated as IH. By taking into consideration the diameter of the reinforcing bar and the covering thickness in this result, it is possible to convert the unit into concrete electric resistivity [Ω · cm] and polarization resistance [Ω · cm 2 ]. The impedance due to the electric double layer capacitance is given by 1 / (2πfC), (where f = frequency, C = electric double layer capacitance), so if the frequency is low, it is better to use the lowest possible frequency. The accuracy is improved, but the lower the frequency, the longer the measuring time is required, so it is practically preferable to use about 0.01 to 1 Hz. As the high frequency, the higher the order, the more accurate the measurement accuracy is. However, if the frequency is too high, radio waves may cause leakage, so
0 kHz is practical.
【００２２】本発明では、測定結果は２点測定の場合、
分極抵抗、コンクリート電気抵抗が、直列回路として加
算された合成分極抵抗、合成コンクリート電気抵抗とな
る。In the present invention, the measurement result is two-point measurement,
The polarization resistance and the concrete electric resistance are added as a series circuit to form the composite polarization resistance and the synthetic concrete electric resistance.
【００２３】次に、各点それぞれの分極抵抗とコンクリ
ート電気抵抗を求める方法を説明する。請求項１におい
て得られた結果は、２点測定の場合、２点の分極抵抗、
コンクリート電気抵抗が合成された値であり、それぞれ
の測定点の分極抵抗、コンクリート電気抵抗率を求める
必要がある場合は、不十分な方法である。そこで、本発
明においては、請求項１で用いた方法で、Ａ点−Ｂ点
間、Ｂ点−Ｃ点間、Ｃ点−Ａ点間等の任意の測定点間で
測定を実施する。Ａ点−Ｂ点間の測定値をＡＢ、Ｂ点−
Ｃ点間の測定値をＢＣ、Ｃ点−Ａ点間の測定値をＣＡと
するとＡ点の分極抵抗、コンクリート電気抵抗は、それ
ぞれ（ＡＢ−ＢＣ＋ＣＡ）／２として計算出来る。Ｂ、
Ｃ点についても同様である。計算で求めたＡ点の測定値
を基準として、Ａ点以外の任意の測定対象間との合成分
極抵抗、合成コンクリート電気抵抗を測定し、この測定
値からＡ点の値を差し引くことで任意の点の分極抵抗、
コンクリート電気抵抗を求める。例えば、Ａ点を基準と
して、Ａ点−Ｄ点間の分極抵抗、コンクリート電気抵抗
を測定した場合は、この測定値から基準点であるＡ点の
分極抵抗、コンクリート電気抵抗を単純に引くことでＤ
点単独の分極抵抗、コンクリート電気抵抗を求めること
が出来る。この一連の操作と単位の変換をコンピュータ
ーによって自動化しておくことも可能である。Next, a method for obtaining the polarization resistance and the concrete electrical resistance at each point will be described. The results obtained in claim 1 are the two points of polarization resistance in the case of two-point measurement,
This is an inadequate method when the concrete electric resistance is a combined value and it is necessary to obtain the polarization resistance and concrete electric resistivity of each measurement point. Therefore, in the present invention, the method used in claim 1 is used to perform measurement between arbitrary measurement points such as between points A and B, between points B and C, and between points C and A. Measured values between A point and B point are AB and B points-
When the measured value between the C points is BC and the measured value between the C point and the A point is CA, the polarization resistance at the A point and the concrete electric resistance can be calculated as (AB-BC + CA) / 2, respectively. B,
The same applies to point C. Using the measured value at point A obtained by calculation as a reference, measure the combined polarization resistance and synthetic concrete electrical resistance with any measurement object other than point A, and subtract the value at point A from this measured value Polarization resistance of the point,
Find the concrete electrical resistance. For example, when the polarization resistance between points A and D and the concrete electric resistance are measured with reference to the point A, the polarization resistance and concrete electric resistance at the reference point A can be simply subtracted from the measured values. D
It is possible to obtain the polarization resistance of a single point and the electric resistance of concrete. It is also possible to automate this series of operations and conversion of units by a computer.
【００２４】[0024]
【実施例】以下、本発明の実施例に基づいて説明する
が、本発明はこれに限定されるものではない。 実施例１ 図２に示す様な検出端を製作し、深さ２ｍ、幅５ｍ、奥
行７ｍのシングル配金である鉄筋コンクリート製の排水
処理槽の底部分の合成分極抵抗、合成コンクリート電気
抵抗の測定を行った。測定に際しては、排水処理槽の液
を測定直前に抜き、たまり水がなく、かつコンクリート
面が湿っている状態で測定した。この処理槽がある工場
は、工業用食塩を製品の原料として使用している為、排
水中には塩素が含まれていた。その為、コンクリート中
には塩分を含有しており、鉄筋は腐食環境にあった。ま
ず、測定にあたり、鉄筋探査機（スイス プロセク社プ
ロフォメーター３）を使用し、鉄筋位置、および、鉄筋
径の測定を行った。測定の結果によれば、以下に述べる
各地点での鉄筋径、及びかぶり厚さは同一であった。検
出端としては、電解質溶液として、水酸化カルシウム飽
和溶液を用い、保水材（ガーゼ）にしみこませたものを
プラスチック筒におさめ、電極としてチタンメッシュ
（エルガード社製チタンメッシュ、タイプ２１０）を内
蔵させたものを２個用意した。照合電極として飽和塩化
銀内極を使用したもの（東亜電波工業社製ＨＳ−２０５
Ｃ）を２個用いて保水材（ガーゼ）上に置き、基準電位
とした。電極、および、照合電極の端子にポテンショス
タット（北斗電工社製ＨＡ−１５０Ｇ）のリード線を接
続した。一方の検出端ａの電極、照合電極には、Ｃ、Ｒ
Ｅ端子を接続し、もう１方の検出端ｂの電極、照合電極
には、ＷＥ１、ＷＥ２リード線をワニ口グリップ付きリ
ード線で接続し、３ｍ離れたコンクリート表面Ａ、Ｂ点
に検出端を設置した。ポテンショスタットに接続されて
いる周波数アナライザー（北斗電工ＦＲＡ５０８０）を
操作し、まず、０．００１Ｈｚの正弦波周波数の電圧３
０ｍＶを印加し、電流を測定した。測定の結果によれ
ば、以下に述べる各地点での鉄筋径、及びかぶり厚さは
同一であった。次に、１ｋＨｚの正弦波周波数の電圧３
０ｍＶを印加し、合成コンクリート電気抵抗と合成分極
抵抗をそれぞれＥH1／ＩH1、ＥL1／ＩL1−ＥH1／ＩH1と
して求めた。その結果、合成分極抵抗、合成コンクリー
ト電気抵抗は、それぞれ１．０ｋΩ、２．０ｋΩであっ
た。EXAMPLES The present invention will be described below based on examples, but the present invention is not limited thereto. Example 1 A detection end as shown in FIG. 2 was manufactured, and a synthetic polarization resistance and a synthetic concrete electric resistance of a bottom portion of a wastewater treatment tank made of reinforced concrete having a depth of 2 m, a width of 5 m, and a depth of 7 m were measured. I went. At the time of measurement, the liquid in the wastewater treatment tank was drained immediately before the measurement, and the measurement was performed in a state where there was no accumulated water and the concrete surface was wet. Since the factory with this treatment tank uses industrial salt as a raw material for its products, the wastewater contained chlorine. Therefore, the concrete contained salt, and the rebar was in a corrosive environment. First, at the time of measurement, a reinforcing bar probe (Profometer 3 of Swiss Prosec Corporation) was used to measure the position of the reinforcing bar and the diameter of the reinforcing bar. According to the measurement results, the reinforcing bar diameter and the cover thickness at each point described below were the same. As the detection end, a saturated calcium hydroxide solution was used as an electrolyte solution, and a material impregnated with a water retaining material (gauze) was placed in a plastic cylinder, and a titanium mesh (titanium mesh type 210 manufactured by Elgard Co., Ltd.) was incorporated as an electrode. I prepared two pieces. A reference electrode using a saturated silver chloride inner electrode (HS-205 manufactured by Toa Denpa Kogyo KK)
Two pieces of C) were used and placed on a water retaining material (gauze) to obtain a reference potential. A lead wire of a potentiostat (HA-150G manufactured by Hokuto Denko Co., Ltd.) was connected to the electrode and the terminal of the reference electrode. C, R are used for the electrode of one detection end a and the reference electrode.
Connect the E terminal, and connect the WE1 and WE2 lead wires to the other electrode of the detection end b and the reference electrode with the lead wire with an alligator grip, and connect the detection end to the concrete surface points A and B 3 m away. installed. Operate the frequency analyzer (Hokuto Denko FRA5080) connected to the potentiostat, and first, the voltage 3 of the sine wave frequency of 0.001Hz.
0 mV was applied and the current was measured. According to the measurement results, the reinforcing bar diameter and the cover thickness at each point described below were the same. Next, voltage 3 with a sine wave frequency of 1 kHz
0 mV was applied, and the synthetic concrete electric resistance and the synthetic polarization resistance were determined as EH1 / IH1 and EL1 / IL1-EH1 / IH1, respectively. As a result, the synthetic polarization resistance and the synthetic concrete electric resistance were 1.0 kΩ and 2.0 kΩ, respectively.
【００２５】参考例１ 検出端ａを１個のみを使用し、測定対象である鉄筋は、
１５ｃｍ×１５ｃｍの範囲ではつり出し、ポテンショス
タットのＷＥ１、ＷＥ２端子を接続した以外は、実施例
１と同様の方法で測定した。まず、Ａ点の分極抵抗、コ
ンクリート電気抵抗を測定したところ、分極抵抗、コン
クリート電気抵抗は、それぞれ０．５ｋΩ、０．９ｋΩ
であった。次に、Ｂ点の分極抵抗、コンクリート電気抵
抗を測定したところ、分極抵抗、コンクリート電気抵抗
は、それぞれ０．５ｋΩ、１．１ｋΩであった。Reference Example 1 Only one detecting end a was used, and the reinforcing bar to be measured was
The measurement was performed in the same manner as in Example 1 except that the projection was made within a range of 15 cm × 15 cm, and the WE1 and WE2 terminals of the potentiostat were connected. First, when the polarization resistance and concrete electric resistance at point A were measured, the polarization resistance and concrete electric resistance were 0.5 kΩ and 0.9 kΩ, respectively.
Met. Next, when the polarization resistance at point B and the concrete electric resistance were measured, the polarization resistance and the concrete electric resistance were 0.5 kΩ and 1.1 kΩ, respectively.
【００２６】実施例２ 実施例１の方法でＡ，Ｂ点間からそれぞれ３ｍ離れた地
点Ｃ点と、Ａ−Ｂ点間、Ｂ−Ｃ点間、Ｃ−Ａ点間の合成
分極抵抗、合成コンクリート電気抵抗の測定を行った。
その結果を表１に示す。Example 2 According to the method of Example 1, a point C 3 m apart from points A and B, a point A-B, a point B-C, a point C-A, a combined polarization resistance, a point The concrete electrical resistance was measured.
Table 1 shows the results.
【表１】 それぞれの点の分極抵抗を、 Ａ点について、〔１．０(A-B点間）−１．１(B-C点間）
＋１．１(C-A点間）〕／２＝０．５ｋΩ Ｂ点について、〔１．１(B-C点間）−１．１(C-A点間）
＋１．０(A-B点間）〕／２＝０．５ｋΩ Ｃ点について、〔１．１(C-A点間）−１．０(A-B点間）
＋１．１(B-C点間）〕／２＝０．６ｋΩ として求め、また、それぞれのコンクリート電気抵抗
を、 Ａ点について、〔２．０(A-B点間）−２．０(B-C点間）
＋１．８(C-A点間）〕／２＝０．９ｋΩ Ｂ点について、〔２．０(B-C点間）−１．８(C-A点間）
＋２．０(A-B点間）〕／２＝１．１ｋΩ Ｃ点について、〔１．８(C-A点間）−２．０(A-B点間）
＋２．０(B-C点間）〕／２＝０．９ｋΩ として求めた。これらの結果をまとめると表２のように
なる。[Table 1] The polarization resistance of each point is [1.0 (between AB points) -1.1 (between BC points) about A point]
+1.1 (between CA points)] / 2 = 0.5 kΩ About B point, [1.1 (between BC points) -1.1 (between CA points)
+1.0 (between AB points)] / 2 = 0.5 kΩ About C point, [1.1 (between CA points) -1.0 (between AB points)
+1.1 (between BC points)] / 2 = 0.6 kΩ, and the electric resistance of each concrete is [2.0 (between AB points) -2.0 (between BC points) about point A.
+1.8 (between CA points)] / 2 = 0.9 kΩ About B point, [2.0 (between BC points) -1.8 (between CA points)
+2.0 (between AB points)] / 2 = 1.1 kΩ About C point, [1.8 (between CA points) -2.0 (between AB points)
+2.0 (between BC points)] / 2 = 0.9 kΩ. The results are summarized in Table 2.
【表２】 その結果、分極抵抗値からのコンクリート中の腐食状況
はＡ、Ｂ、Ｃ点とも腐食大であった。又、コンクリート
電気抵抗率値からのコンクリート中の腐食状況もＡ、
Ｂ、Ｃ点とも腐食大であった。この結果は、従来の方法
で得られた結果とも一致し、評価判断には信憑性がある
（参考例２参照）。[Table 2] As a result, the state of corrosion in concrete from the polarization resistance value was large at points A, B, and C. Also, the corrosion status in concrete from the concrete electrical resistivity value is A,
Corrosion was large at both points B and C. This result is consistent with the result obtained by the conventional method, and the evaluation judgment is credible (see Reference Example 2).
【００２７】参考例２ 参考例１の方法で、実施例２のＡ、Ｂ、Ｃ点それぞれの
分極抵抗、コンクリート電気抵抗を測定した。その結果
を表３に示す。Reference Example 2 By the method of Reference Example 1, the polarization resistance and concrete electric resistance at points A, B and C of Example 2 were measured. Table 3 shows the results.
【表３】 [Table 3]
【００２８】[0028]
【発明の効果】本発明によれば、ＡＣインピーダンス法
において、コンクリート中の鋼材の一部への導線の接続
が必要ないので、従来の方法の様な鋼材露出の為のはつ
り作業やコアリング作業を省略でき、コンクリート構造
物中の鋼材の腐食状況を非破壊的に評価することができ
る。従って、労力の軽減効果があり、また、コンクリー
ト構造物の破壊行為を必要としない利点がある。According to the present invention, in the AC impedance method, it is not necessary to connect a conducting wire to a part of the steel material in the concrete, and therefore, the chipping work and coring work for exposing the steel material unlike the conventional method. Can be omitted, and the corrosion status of steel in concrete structures can be evaluated nondestructively. Therefore, there is an effect of reducing labor, and there is an advantage that the act of destroying the concrete structure is not required.
【図１】図１は、ＡＣインピーダンス法によるコンクリ
ート電気抵抗、分極抵抗、電気二重層容量の電気回路で
ある。FIG. 1 is an electric circuit of concrete electric resistance, polarization resistance, and electric double layer capacitance by the AC impedance method.
【図２】図２は、実施例１〜２で用いた測定装置であ
る。FIG. 2 is a measuring device used in Examples 1 and 2.
１ コンクリート ２ 鋼材 ３ 分極抵抗Ｒp ４ コンクリート電気抵抗Ｒs ５ 電気二重層容量Ｃ ６ 電極 ７ 照合電極 ８ 保水材 ９ プラスチック筒 １０ ポテンショスタット又はガルバノスタット １１ 周波数アナライザー1 concrete 2 steel material 3 polarization resistance R p 4 concrete electric resistance R s 5 electric double layer capacity C 6 electrode 7 reference electrode 8 water retention material 9 plastic cylinder 10 potentiostat or galvanostat 11 frequency analyzer
Claims (2)
をコンクリート表面に接触させ、該電極間に交流電流を
流すことを特徴とするコンクリート中の鋼材の腐食箇所
検出方法。1. A method for detecting a corrosion location of steel in concrete, characterized in that two or more steel corrosion detection ends equipped with electrodes are brought into contact with the concrete surface, and an alternating current is passed between the electrodes.
所以上の鋼材の分極抵抗又はコンクリート電気抵抗率を
測定することを特徴とする請求項１記載のコンクリート
中の鋼材の腐食箇所検出方法。2. The method for detecting a corrosion location of steel in concrete according to claim 1, wherein the polarization resistance or the concrete electrical resistivity of two or more steel materials in the concrete is measured by passing an alternating current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00504196A JP3326587B2 (en) | 1996-01-16 | 1996-01-16 | Method for detecting corrosion points of steel in concrete |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00504196A JP3326587B2 (en) | 1996-01-16 | 1996-01-16 | Method for detecting corrosion points of steel in concrete |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09196876A true JPH09196876A (en) | 1997-07-31 |
| JP3326587B2 JP3326587B2 (en) | 2002-09-24 |
Family
ID=11600360
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP00504196A Expired - Fee Related JP3326587B2 (en) | 1996-01-16 | 1996-01-16 | Method for detecting corrosion points of steel in concrete |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3326587B2 (en) |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000044364A (en) * | 1998-07-22 | 2000-02-15 | Denki Kagaku Kogyo Kk | Detection of repair-needing portion of concrete structure and its repair |
| WO2002057729A1 (en) * | 2001-01-20 | 2002-07-25 | Technische Universität Braunschweig | State identification of electrically conductive oblong tensioning elements using resonance frequencies and a computer program |
| KR20030060259A (en) * | 2002-01-08 | 2003-07-16 | 심욱서 | Current counter of anti-corroded object in an electric anti-corrosion system |
| JP2011022032A (en) * | 2009-07-16 | 2011-02-03 | Tohoku Univ | Measuring method of concrete volume resistivity and device therefor |
| JP2011080913A (en) * | 2009-10-08 | 2011-04-21 | Hiroshima Prefecture | Method and apparatus for sensing reinforcing bar when cutting to-be-cut object including cutting apparatus |
| KR101379264B1 (en) * | 2012-08-31 | 2014-03-28 | 삼성중공업 주식회사 | Device and method for monitoring corrosion of wind power generator tower |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000044364A (en) * | 1998-07-22 | 2000-02-15 | Denki Kagaku Kogyo Kk | Detection of repair-needing portion of concrete structure and its repair |
| WO2002057729A1 (en) * | 2001-01-20 | 2002-07-25 | Technische Universität Braunschweig | State identification of electrically conductive oblong tensioning elements using resonance frequencies and a computer program |
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| JP2011022032A (en) * | 2009-07-16 | 2011-02-03 | Tohoku Univ | Measuring method of concrete volume resistivity and device therefor |
| JP2011080913A (en) * | 2009-10-08 | 2011-04-21 | Hiroshima Prefecture | Method and apparatus for sensing reinforcing bar when cutting to-be-cut object including cutting apparatus |
| KR101379264B1 (en) * | 2012-08-31 | 2014-03-28 | 삼성중공업 주식회사 | Device and method for monitoring corrosion of wind power generator tower |
| JP2018017517A (en) * | 2016-07-25 | 2018-02-01 | 株式会社Ｎｔｔファシリティーズ | Corrosion degree estimation method, corrosion degree estimation device and program |
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