JP2000028567A - Neutralization detecting method for concrete structural body, and neutralization detecting sensor - Google Patents
Neutralization detecting method for concrete structural body, and neutralization detecting sensorInfo
- Publication number
- JP2000028567A JP2000028567A JP10194552A JP19455298A JP2000028567A JP 2000028567 A JP2000028567 A JP 2000028567A JP 10194552 A JP10194552 A JP 10194552A JP 19455298 A JP19455298 A JP 19455298A JP 2000028567 A JP2000028567 A JP 2000028567A
- Authority
- JP
- Japan
- Prior art keywords
- neutralization
- electrode
- concrete
- concrete structure
- metal element
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、コンクリート構造
体の中性化進行状況を検出する方法及び同検出に用いる
中性化検出センサに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the progress of neutralization of a concrete structure and a neutralization detection sensor used for the detection.
【０００２】[0002]
【従来の技術】鉄筋コンクリート製の建造物などのコン
クリートは本来は強アルカリ性（ｐＨ＝１２．５程度）
を示す。これらのコンクリートは大気中の弱酸性の炭酸
ガスと反応して炭酸カルシウムを生成し、ｐＨが８．５
〜１０程度になる。このような現象をコンクリートの中
性化と呼んでいる。このコンクリートの中性化が進むと
コンクリート中の鉄筋が発錆し、約２．５倍に体積膨張
する。この膨張に伴いコンクリートにひび割れが発生
し、かぶりコンクリートの剥離を招く。そこで、コンク
リート構造物などの耐久性を考える上で、コンクリート
の中性化進行状況を把握することが重要となる。2. Description of the Related Art Concrete, such as a reinforced concrete building, is inherently strongly alkaline (pH = 12.5).
Is shown. These concretes react with weakly acidic carbon dioxide in the atmosphere to produce calcium carbonate, and have a pH of 8.5.
About 10 to 10. Such a phenomenon is called neutralization of concrete. When the carbonation of the concrete progresses, the reinforcing steel in the concrete rusts, and the volume expands about 2.5 times. The expansion causes cracks in the concrete, which causes exfoliation of the cover. Therefore, when considering the durability of concrete structures and the like, it is important to grasp the progress of carbonation of concrete.
【０００３】従来、このコンクリートの中性化を測定す
る方法として、フェノールフタレイン法、示差熱重量分
析法、Ｘ線回析法などが一般的に知られている。フェノ
ールフタレイン法は、フェノールフタレインがｐＨ８．
２〜１０．０以上のアルカリ側では紅色に発色し、中性
では無色であることを利用し、フェノールフタレインの
１％エタノール溶液をコンクリートに吹き付け、コンク
リート表面から発色点までの長さで中性化の進行度を求
めるものである。Conventionally, as a method for measuring the neutralization of concrete, a phenolphthalein method, a differential thermogravimetric analysis method, an X-ray diffraction method and the like are generally known. In the phenolphthalein method, phenolphthalein has a pH of 8.
Spraying 1% ethanol solution of phenolphthalein onto concrete using the fact that it develops a red color on the alkaline side of 2 to 10.0 or more and is colorless in neutral, This is to determine the degree of sexual development.
【０００４】この方法は、最も一般的に使用される方法
であるが、試薬の噴霧量、コンクリートの表面状態又は
試薬の吹き付け時期などにより誤差を生じやすく、また
ｐＨを直読できないという欠点がある。This method is the most commonly used method, but has the drawback that errors tend to occur depending on the amount of reagent sprayed, the surface condition of concrete or the timing of spraying the reagent, and the pH cannot be read directly.
【０００５】示差熱重量分析法は、コンクリートの温度
を上げて熱変化に対応する重量変化を測定する方法と、
温度変化に伴って起こる反応が吸熱か発熱かを調べる方
法とを組み合わせた方法である。これらの方法は、測定
精度は高いが、大がかりな装置を必要とするという欠点
がある。Ｘ線回析法は、コンクリート構造体にＸ線を照
射して回析線の強度パターンを調べる方法であるが、半
定量分析しか行えず、また大がかりな装置を必要とする
欠点がある。[0005] Differential thermogravimetric analysis is a method of measuring the weight change corresponding to the heat change by raising the temperature of concrete;
This is a method combining a method of examining whether the reaction accompanying the temperature change is endothermic or exothermic. Although these methods have high measurement accuracy, they have the disadvantage of requiring large-scale equipment. The X-ray diffraction method is a method of irradiating a concrete structure with X-rays and examining the intensity pattern of the diffraction lines, but has a disadvantage that only a semi-quantitative analysis can be performed and a large-scale apparatus is required.
【０００６】また、上記の方法のいずれも既存のコンク
リートを局部的に破壊してサンプルを採らなければなら
ず、またコンクリート中性化の経時変化をリアルタイム
で測定することはできない。[0006] Further, in any of the above-mentioned methods, a sample must be taken by locally destroying existing concrete, and the change with time of the carbonation of concrete cannot be measured in real time.
【０００７】一方、既設のコンクリートを局部的に破壊
してサンプルを採取せずに、コンクリート中性化を測定
する方法が、特開平９−１７１０１２号公報に開示され
ている。この方法は、コンクリート中に所定間隔を置い
て埋設したニッケル又は亜鉛の同材質金属からなる二個
の電極の電位差を計測してコンクリートの中性化を検知
するものである。On the other hand, Japanese Patent Application Laid-Open No. Hei 9-171012 discloses a method for measuring the neutralization of concrete without locally destroying existing concrete and collecting a sample. In this method, the neutralization of concrete is detected by measuring the potential difference between two electrodes made of the same material metal of nickel or zinc embedded at a predetermined interval in concrete.
【０００８】この方法は、ニッケル又は亜鉛がｐＨ１０
前後で不動態化する性質を利用したものであり、前記ｐ
Ｈから外れると中性化を感知することはできない。ま
た、ｐＨの変化によるコンクリートの中性化の進行状況
を連続的に検知することもできない。In this method, nickel or zinc has a pH of 10 or less.
Utilizing the property of passivation before and after,
If it deviates from H, neutralization cannot be sensed. Further, it is impossible to continuously detect the progress of carbonation of concrete due to a change in pH.
【０００９】[0009]
【発明が解決しようとする課題】本発明は、従来技術に
おける上記の問題点を解消し、コンクリート構造体を破
壊してサンプルを採取することなく、リアルタイムでコ
ンクリートのｐＨ変化を簡単に感知することができ、コ
ンクリートの中性化進行状況を連続的に検知できるコン
クリート構造体の中性化検出方法及びその検出に用いる
中性化検出センサを提供しようとするものである。SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems in the prior art, and to easily detect a pH change of concrete in real time without destroying a concrete structure and taking a sample. It is an object of the present invention to provide a neutralization detecting method for a concrete structure capable of continuously detecting the progress of carbonation of concrete, and a neutralization detecting sensor used for the detection.
【００１０】[0010]
【課題を解決するための手段】本発明者等は、上記課題
を解決するために研究を重ねた結果、周期律表第５族の
金属元素又は該金属元素の１種以上を基体とする合金、
特にビスマス、アンチモン又はそれらの合金がｐＨの変
化に対応した電位変化を示すところから、これらの金属
元素又は合金を測定電極とし、照合電極とともに測定対
象コンクリート構造体中に埋設するか、又は、前記金属
元素又は合金からなる電極を複数埋設し、前記構造体の
コンクリートを介した測定電極と照合電極との間の電位
差、又は、複数の電極間の電位差を計測することによ
り、コンクリート構造体のｐＨを検知して中性化の進行
度を把握することに成功した。即ち、本発明の構成は、
以下のとおりである。Means for Solving the Problems As a result of repeated studies to solve the above problems, the present inventors have found that a metal element of Group 5 of the periodic table or an alloy containing at least one of the above metal elements as a base material ,
In particular, bismuth, antimony or their alloys show potential changes corresponding to changes in pH, so these metal elements or alloys are used as measurement electrodes and embedded in a concrete structure to be measured together with a reference electrode, or By embedding a plurality of electrodes made of metal elements or alloys and measuring the potential difference between the measurement electrode and the reference electrode via concrete of the structure, or the potential difference between the plurality of electrodes, the pH of the concrete structure is measured. To detect the progress of neutralization. That is, the configuration of the present invention is:
It is as follows.
【００１１】(1) 測定電極及び照合電極を測定対象コン
クリート構造体中に埋設し、該構造体のコンクリートを
介した該測定電極と該照合電極との間の電位差を計測し
てコンクリート構造体の中性化を検出する方法におい
て、前記測定電極を、周期律表第５族に属する金属元素
又は該金属元素の１種以上を基体とする合金で構成する
ことを特徴とするコンクリート構造体の中性化検出方
法。 (2) 前記測定電極を複数用い、前記測定対象コンクリー
ト構造体の深さ方向に前記測定電極を予め設定した間隔
で埋設し、前記深さ方向の中性化の進行度を検出するこ
とを特徴とする前記(1) 記載のコンクリート構造体の中
性化検出方法。(1) A measurement electrode and a reference electrode are embedded in a concrete structure to be measured, and a potential difference between the measurement electrode and the reference electrode through concrete of the structure is measured to measure the concrete structure. In the method for detecting neutralization, the measurement electrode is formed of a metal element belonging to Group 5 of the periodic table or an alloy having at least one of the metal elements as a base. Sex detection method. (2) using a plurality of the measurement electrodes, burying the measurement electrodes at predetermined intervals in the depth direction of the concrete structure to be measured, and detecting the degree of progress of neutralization in the depth direction. The method for detecting neutralization of a concrete structure according to the above (1).
【００１２】(3) 複数の電極を測定対象コンクリート構
造体中に埋設し、該構造体のコンクリートを介した前記
複数の電極間の電位差を計測してコンクリート構造体の
中性化を検出する方法において、前記電極を、周期律表
第５族に属する金属元素又は該金属元素の１種以上を基
体とする合金で構成することを特徴とするコンクリート
構造体の中性化検出方法。 (4) 前記測定対象コンクリート構造体の深さ方向に前記
複数の電極を予め設定した間隔で埋設し、前記深さ方向
の中性化の進行度を検出することを特徴とする前記(3)
記載のコンクリート構造体の中性化検出方法。(3) A method of embedding a plurality of electrodes in a concrete structure to be measured and measuring neutralization of the concrete structure by measuring a potential difference between the plurality of electrodes via the concrete of the structure. 3. The method for detecting neutralization of a concrete structure according to claim 1, wherein the electrode is made of a metal element belonging to Group 5 of the periodic table or an alloy having at least one of the metal elements as a base. (4) The plurality of electrodes are buried at predetermined intervals in a depth direction of the concrete structure to be measured, and the progress of neutralization in the depth direction is detected, wherein (3)
The method for detecting neutralization of a concrete structure according to the above.
【００１３】(5) 周期律表第５族に属する前記金属元素
がビスマス又はアンチモンであることを特徴とする前記
(1) 〜(4) のいずれか１つに記載のコンクリート構造体
の中性化検出方法。 (6) 周期律表第５族に属する金属元素又は該金属元素の
１種以上を基体とする合金からなる前記電極が、前記金
属元素の酸化皮膜又は水酸化皮膜を有することを特徴と
する前記(1) 〜(5) のいずれか１つに記載のコンクリー
ト構造体の中性化検出方法。(5) The metal element belonging to Group 5 of the periodic table is bismuth or antimony.
The method for detecting neutralization of a concrete structure according to any one of (1) to (4). (6) The electrode comprising a metal element belonging to Group 5 of the periodic table or an alloy having at least one of the metal elements as a base, wherein the electrode has an oxide film or a hydroxide film of the metal element. (1) The method for detecting neutralization of a concrete structure according to any one of (1) to (5).
【００１４】(7) 測定対象コンクリート構造体中に埋設
するコンクリートの中性化検出センサにおいて、周期律
表第５族に属する金属元素又は該金属元素の１種以上を
基体とする合金からなる測定電極及び照合電極を、少な
くともその一部が露出するように絶縁体に支持又は埋設
し、前記電極を電位差測定計と電気的に接続する手段を
設け、該構造体のコンクリートを介した該測定電極と該
照合電極との間の電位差を計測可能にしたことを特徴と
するコンクリート構造体の中性化検出センサ。 (8) 前記測定電極を複数用い、前記測定対象コンクリー
ト構造体の深さ方向に前記測定電極を予め設定した間隔
で埋設し、前記深さ方向の中性化の進行度の検出を可能
にしたことを特徴とする前記(7) 記載のコンクリート構
造体の中性化検出センサ。(7) A neutralization detection sensor for concrete buried in a concrete structure to be measured, comprising a metal element belonging to Group 5 of the periodic table or an alloy containing at least one of the metal elements as a base material. The electrode and the reference electrode are supported or buried in an insulator so that at least a part of the electrode and the reference electrode are exposed, and means for electrically connecting the electrode to a potentiometer is provided. A neutralization detection sensor for a concrete structure, wherein a potential difference between the concrete structure and the reference electrode can be measured. (8) Using a plurality of the measurement electrodes, burying the measurement electrodes at predetermined intervals in the depth direction of the concrete structure to be measured, enabling the detection of the degree of neutralization progress in the depth direction. The neutralization detection sensor according to the above (7), wherein:
【００１５】(9) 測定対象コンクリート構造体中に埋設
するコンクリートの中性化検出センサにおいて、周期律
表第５族に属する金属元素又は該金属元素の１種以上を
基体とする合金からなる電極を複数用意し、各電極の少
なくともその一部が露出するように絶縁体に支持又は埋
設し、前記複数の電極をそれぞれ電位差測定計と電気的
に接続する手段を設け、該構造体のコンクリートを介
し、前記電極間の電位差を計測可能にしたことを特徴と
するコンクリート構造体の中性化検出センサ。 (10)前記測定対象コンクリート構造体の深さ方向に前記
複数の電極を予め設定した間隔で埋設し、前記深さ方向
の中性化の進行度の検出を可能にしたことを特徴とする
前記(9) 記載のコンクリート構造体の中性化検出セン
サ。(9) In a neutralization detection sensor for concrete embedded in a concrete structure to be measured, an electrode made of a metal element belonging to Group 5 of the periodic table or an alloy containing at least one of the metal elements as a base material A plurality of, each electrode is supported or buried in an insulator so that at least a part of each electrode is exposed, means for electrically connecting each of the plurality of electrodes to a potentiometer is provided, and concrete of the structure is provided. A neutralization detection sensor for a concrete structure, wherein a potential difference between the electrodes can be measured through the intermediary of the electrode. (10) The plurality of electrodes are buried at predetermined intervals in the depth direction of the concrete structure to be measured, and the degree of neutralization in the depth direction can be detected. (9) The neutralization detection sensor of the concrete structure according to (9).
【００１６】(11)周期律表第５族に属する前記金属元素
がビスマス又はアンチモンであることを特徴とする前記
(7) 〜(10)のいずれか１つに記載のコンクリート構造体
の中性化検出センサ。 (12)周期律表第５族に属する金属元素又は該金属元素の
１種以上を基体とする合金からなる前記電極が、前記金
属元素の酸化皮膜又は水酸化皮膜を有することを特徴と
する前記(7) 〜(11)のいずれか１つに記載のコンクリー
ト構造体の中性化検出センサ。(11) The metal element belonging to Group 5 of the periodic table is bismuth or antimony.
(7) The neutralization detection sensor according to any one of (7) to (10). (12) the electrode comprising a metal element belonging to Group 5 of the periodic table or an alloy having at least one of the metal elements as a base, wherein the electrode has an oxide film or a hydroxide film of the metal element. (7) The neutralization detection sensor according to any one of (7) to (11).
【００１７】[0017]
【発明の実施の形態】以下、本発明の実施の形態を図に
基づいて説明する。図１は本発明のコンクリート中性化
検知方法の一実施例を示す概略断面図である。図におい
て、１は測定対象となるコンクリート構造体、２はコン
クリート中性化検知センサである。このセンサ２は、長
尺の絶縁性筒体３と、ビスマス、アンチモン等の周期律
表第５族の金属元素のいずれか１種からなる複数の測定
電極５と、照合電極６とからなり、前記筒体３の高さ方
向に予め設定した間隔で穴を開け、それぞれの穴から前
記測定電極５を外部に露出させ、前記筒体３の底部から
前記照合電極６を露出させ、測定電極５からのリード線
７及び照合電極６からのリード線８をスリーブ９を介し
て前記筒体３の上部から引き出した状態で絶縁性樹脂４
を充填して構成したものである。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing an embodiment of the concrete neutralization detecting method of the present invention. In the figure, 1 is a concrete structure to be measured, and 2 is a concrete neutralization detection sensor. The sensor 2 includes a long insulating cylinder 3, a plurality of measurement electrodes 5 made of any one of the Group 5 metal elements of the periodic table such as bismuth and antimony, and a reference electrode 6. Holes are formed at predetermined intervals in the height direction of the cylindrical body 3, the measurement electrodes 5 are exposed to the outside from the respective holes, the reference electrodes 6 are exposed from the bottom of the cylindrical body 3, and the measurement electrodes 5 are formed. The lead wire 7 from the lead and the lead wire 8 from the reference electrode 6 are pulled out from the upper part of the cylindrical body 3 through the sleeve 9 and the insulating resin 4
Is filled.
【００１８】前記センサ２は、前記スリーブ９の一端を
外部に露出するように、コンクリート構造体１に埋設す
る。前記スリーブ９を介して引き出された測定電極５の
リード線７は接続切り換え器１１に接続し、照合電極の
リード線８は電位差測定計１０に接続し、かつ、接続切
り換え器１１と電位差測定計１０をリード線で接続す
る。The sensor 2 is embedded in the concrete structure 1 so that one end of the sleeve 9 is exposed to the outside. The lead 7 of the measuring electrode 5 drawn out through the sleeve 9 is connected to a connection switch 11, the lead 8 of the reference electrode is connected to a potentiometer 10, and the switch 11 and the potentiometer are connected. 10 is connected by a lead wire.
【００１９】前記筒体３の外部に露出した測定電極５及
び照合電極６は、互いに直接電気回路が形成されること
はなく、測定対象のコンクリート構造体のコンクリート
と電気的に導通性を保持する必要がある。この電気的導
通性を保持するために、電極を前記筒体３から突出させ
るか、水を含ませた親水性プラスチック多孔質材やスポ
ンジなどの電気導通性を有する部材を前記電極の先端に
張り付けることが好ましい。The measurement electrode 5 and the reference electrode 6 exposed to the outside of the cylindrical body 3 do not directly form an electric circuit with each other, and maintain electrical conductivity with the concrete of the concrete structure to be measured. There is a need. In order to maintain the electrical conductivity, an electrode is projected from the cylindrical body 3 or a member having electrical conductivity such as a hydrophilic plastic porous material or sponge impregnated with water is attached to the tip of the electrode. Preferably.
【００２０】測定対象コンクリート構造体１に設置され
たセンサ２は、測定電極５を接続切り換え器１１で順次
切り換え、測定電極５と照合電極６との間の電位差を電
位差測定計１０で計測して、コンクリート構造体のｐＨ
を検知して中性化の進行度を把握する。The sensor 2 installed on the concrete structure 1 to be measured sequentially switches the measuring electrodes 5 with the connection switching device 11 and measures the potential difference between the measuring electrode 5 and the reference electrode 6 with the potentiometer 10. , PH of concrete structure
To detect the progress of neutralization.
【００２１】なお、測定電極５は１つでもよいし、照合
電極６を省略して、測定電極の１つを照合電極として使
用してもよい。また、前記絶縁性筒体３を省略してもよ
い。さらに、測定対象コンクリート構造体にセンサを埋
設する穴を開けて、前記測定電極及び照合電極の先端が
前記のコンクリートに導通するように保持し、前記電極
からリード線を引き出した状態で絶縁性樹脂などを充填
してセンサを構成してもよい。The number of the measuring electrodes 5 may be one, or the reference electrode 6 may be omitted and one of the measuring electrodes may be used as the reference electrode. Further, the insulating cylinder 3 may be omitted. Further, a hole for embedding a sensor is formed in the concrete structure to be measured, and the tip of the measurement electrode and the reference electrode is held so as to be electrically connected to the concrete. Alternatively, the sensor may be configured by filling the above.
【００２２】[0022]
【実施例】次に本発明の実施例を図面に基づいて説明す
る。 （１）予備試験 ビスマス（Ｂｉ）、酸化処理したビスマス（Ｂｉ
2 Ｏ3 ）、マグネシウム（Ｍｇ）、ニッケル（Ｎｉ）、
ステンレス鋼（ＳＵＳ）及びアンチモン（Ｓｂ）を２５
℃飽和水酸化カルシウム溶液に浸漬してこれらの金属の
自然電位の経時変化を測定し、結果を図２に示した。Next, an embodiment of the present invention will be described with reference to the drawings. (1) Preliminary test Bismuth (Bi), oxidized bismuth (Bi)
2 O 3 ), magnesium (Mg), nickel (Ni),
25 stainless steel (SUS) and antimony (Sb)
These metals were immersed in a calcium hydroxide solution saturated at ℃ to measure the change over time in the natural potential of these metals, and the results are shown in FIG.
【００２３】図２から明らかなように、Ｂｉ2 Ｏ3 の自
然電位は浸漬後約５０分で、Ｂｉの自然電位が浸漬後約
１２時間で、Ｓｂが浸漬後約２２時間で安定したが、Ｍ
ｇ、Ｎｉ及びＳＵＳは浸漬開始後、１６８時間経過して
試験を終了するまで自然電位の安定は見られなかった。As is apparent from FIG. 2, the natural potential of Bi 2 O 3 was stabilized at about 50 minutes after immersion, the natural potential of Bi was stabilized at about 12 hours after immersion, and Sb was stabilized at about 22 hours after immersion. M
g, Ni, and SUS did not exhibit a stable natural potential until the test was terminated after 168 hours from the start of immersion.
【００２４】次に、上記試験で自然電位の安定性が良か
ったＢｉ及びＳｂと、比較用ガラス電極を２５℃飽和水
酸化カルシウム溶液に浸漬した後、該飽和水酸化カルシ
ウム溶液を順次希釈してｐＨを順次降下させるときの、
Ｂｉ、Ｓｂ及びガラス電極の電位変化を飽和甘こう電極
を基準にして測定し、結果を図３に示した。図３から明
らかなように、それらは非常に良い相関性が得られ、Ｂ
ｉ及びＳｂがコンクリート中性化検出センサとして適し
ていることが確認できた。Next, Bi and Sb, whose stability of the natural potential was good in the above test, and a glass electrode for comparison were immersed in a saturated calcium hydroxide solution at 25 ° C., and the saturated calcium hydroxide solution was sequentially diluted. When decreasing the pH sequentially,
The potential changes of Bi, Sb and the glass electrode were measured with reference to the saturated luster electrode, and the results are shown in FIG. As is evident from FIG. 3, they have very good correlation and B
It was confirmed that i and Sb were suitable as concrete neutralization detection sensors.
【００２５】（２）実施例 直径２．６ｃｍ、高さ７ｃｍ、肉厚０．３ｃｍの塩化ビ
ニル管を用い、その上端から１ｃｍ、さらに１ｃｍ間隔
で長手方向に５か所の穴を開け、表面を酸化処理した直
径０．２ｃｍ、長さ１．２ｃｍのビスマス製の測定電極
を５個用意し、それぞれの先端を塩化ビニル管の穴に挿
入して外部に０．３ｃｍ突出させ、それぞれの測定電極
の後端に接続したリード線を塩化ビニル管の上部から引
き出し、また直径１ｃｍ、長さ２ｃｍの鉛照合電極を、
塩化ビニル管の底部から０．３ｃｍ突出させ、鉛照合電
極の後端に接続したリード線も塩化ビニル管の上部から
引き出した状態で、塩化ビニル管内部にエポキシ樹脂を
充填して硬化させて図１に示すコンクリート中性化検知
センサ２を製作した。(2) Example A vinyl chloride tube having a diameter of 2.6 cm, a height of 7 cm, and a wall thickness of 0.3 cm was used, and five holes were made in the longitudinal direction at intervals of 1 cm and 1 cm from the upper end thereof. Prepare five measurement electrodes made of bismuth made by oxidation treatment and having a diameter of 0.2 cm and a length of 1.2 cm. Insert each tip into the hole of the vinyl chloride tube and project it to the outside by 0.3 cm. The lead wire connected to the rear end of the electrode was pulled out from the top of the PVC pipe, and a lead reference electrode 1 cm in diameter and 2 cm in length was inserted.
With the lead protruding 0.3 cm from the bottom of the PVC pipe and the lead wire connected to the rear end of the lead reference electrode pulled out from the top of the PVC pipe, the inside of the PVC pipe is filled with epoxy resin and cured. The concrete neutralization detection sensor 2 shown in FIG.
【００２６】そして、図１に示すように、縦横各３０ｃ
ｍ、厚さ１０ｃｍの直方体のモルタル供試体中に、塩化
ビニル管の先端の深さが７．５ｃｍとなるようにコンク
リート中性化検知センサ２を埋設した。前記モルタル供
試体を炭酸ガス雰囲気中に暴露して測定電極と照合電極
の間の電位差を３５０日間測定し、結果を図４に示し
た。図４から明らかなように、試験開始当初は各測定電
極（上段からＥ１〜Ｅ５と呼ぶ）とも飽和甘こう電極換
算値で約−４５５ｍＶの電位を示していたが、最上段の
測定電極（Ｅ１）の電位は、試験開始約２２日目から貴
（プラス側）方向に以降し始め、約１６０日目以降は約
−２４０ｍＶで安定した。Then, as shown in FIG.
The concrete neutralization detection sensor 2 was embedded in a rectangular parallelepiped mortar specimen having a thickness of 10 cm and a thickness of 10 cm so that the depth of the tip of the vinyl chloride pipe became 7.5 cm. The mortar specimen was exposed to a carbon dioxide gas atmosphere, and the potential difference between the measurement electrode and the reference electrode was measured for 350 days. The results are shown in FIG. As is clear from FIG. 4, at the beginning of the test, each of the measurement electrodes (referred to as E1 to E5 from the upper row) showed a potential of about -455 mV in terms of a saturated gall electrode, but the uppermost measurement electrode (E1 The potential of ()) began to increase in the noble (positive side) direction from about the 22nd day of the test, and stabilized at about -240 mV after about the 160th day.
【００２７】２段目の測定電極（Ｅ２）の電位は、試験
開始後約５０日目から貴方向に以降し始め、試験終了時
（３５０日目）には−２４４ｍＶを示した。３段目の測
定電極（Ｅ３）の電位は、試験開始後約１２０日目から
貴方向に以降し始め、試験終了時（３５０日目）には−
２４３ｍＶを示した。なお、４段目と５段目の測定電極
（Ｅ４とＥ５）の電位は、本試験期間（３５０日間）中
殆ど電位の変動は見られなかった。The potential of the measurement electrode (E2) at the second stage began to increase in the noble direction from about the 50th day after the start of the test, and at the end of the test (350th day) showed -244 mV. The potential of the third-stage measurement electrode (E3) starts to increase in the noble direction from about 120 days after the start of the test, and at the end of the test (350 days),
243 mV. The potentials of the measurement electrodes (E4 and E5) at the fourth and fifth stages showed almost no fluctuation during the test period (350 days).
【００２８】試験終了後、前記モルタル供試体を割裂
し、フェノールフタレイン１％指示薬を散布して中性化
の進行深さを調査したところ、フェノールフタレイン１
％指示薬によるモルタル供試体の変色域は、表面から深
さ約３．５ｃｍの範囲に及んでおり、各測定電極が示す
電位から想定される中性化深さと非常に良い相関性を示
した。After the test was completed, the mortar specimen was cleaved, and a phenolphthalein 1% indicator was sprayed to examine the depth of progress of neutralization.
The discoloration area of the mortar specimen with the% indicator extended to a depth of about 3.5 cm from the surface, and showed a very good correlation with the neutralization depth assumed from the potential indicated by each measurement electrode.
【００２９】[0029]
【発明の効果】本発明は、前記の構成を採用することに
より、測定対象コンクリート構造体を局部的破壊してサ
ンプルを採取することなく、簡単にかつ確実にコンクリ
ートの中性化の経時変化を測定することができるように
なった。また、複数の測定電極を、コンクリート構造体
に予め設定した間隔で埋設深さを変えることにより、コ
ンクリート構造体の中性化の進行度を簡単に把握できる
ようになった。According to the present invention, by adopting the above-mentioned structure, it is possible to easily and surely prevent the change of concrete neutralization with time without causing local destruction of the concrete structure to be measured and taking a sample. Now you can measure. In addition, by changing the embedding depth of a plurality of measurement electrodes at predetermined intervals in a concrete structure, the progress of neutralization of the concrete structure can be easily grasped.
【図１】本発明のコンクリート中性化検知方法の一実施
例を説明するための概略断面図である。FIG. 1 is a schematic sectional view for explaining an embodiment of a concrete neutralization detecting method according to the present invention.
【図２】各種金属の２５℃飽和水酸化カルシウム溶液中
の自然電位の変化を表したグラフである。FIG. 2 is a graph showing the change in the natural potential of various metals in a 25 ° C. saturated calcium hydroxide solution.
【図３】水酸化カルシウム溶液に浸漬したビスマス、ア
ンチモンとガラス電極の電位−ｐＨ相関を示したグラフ
である。FIG. 3 is a graph showing a potential-pH relationship between bismuth and antimony immersed in a calcium hydroxide solution and a glass electrode.
【図４】炭酸ガス雰囲気中に暴露したモルタル供試体中
の酸化処理したビスマス製測定電極の電位の経時変化を
示したグラフである。FIG. 4 is a graph showing the change over time of the potential of an oxidized bismuth measuring electrode in a mortar specimen exposed to a carbon dioxide gas atmosphere.
１ コンクリート構造体、 ２ コンクリート中性化検
知センサ、 ３ 筒体、 ４ 絶縁性樹脂、 ５ 測定
電極、 ６ 照合電極、 ７ 測定電極用リード線、
８ 照合電極用リード線、 ９ スリーブ、 １０ 電
位差測定計、１１ 接続切り換え器。1 concrete structure, 2 concrete neutralization detection sensor, 3 cylinder, 4 insulating resin, 5 measuring electrode, 6 reference electrode, 7 lead wire for measuring electrode,
8 Lead wire for reference electrode, 9 Sleeve, 10 Potentiometer, 11 Connection changer.
Claims (8)
リート構造体中に埋設し、該構造体のコンクリートを介
した該測定電極と該照合電極との間の電位差を計測して
コンクリート構造体の中性化を検出する方法において、
前記測定電極を、周期律表第５族に属する金属元素又は
該金属元素の１種以上を基体とする合金で構成すること
を特徴とするコンクリート構造体の中性化検出方法。1. A measurement electrode and a reference electrode are embedded in a concrete structure to be measured, and a potential difference between the measurement electrode and the reference electrode via concrete of the structure is measured to measure the potential difference between the measurement electrode and the reference electrode. In the method of detecting sexing,
A neutralization detection method for a concrete structure, wherein the measurement electrode is formed of a metal element belonging to Group 5 of the periodic table or an alloy having at least one of the metal elements as a base.
体中に埋設し、該構造体のコンクリートを介した前記複
数の電極間の電位差を計測してコンクリート構造体の中
性化を検出する方法において、前記電極を、周期律表第
５族に属する金属元素又は該金属元素の１種以上を基体
とする合金で構成することを特徴とするコンクリート構
造体の中性化検出方法。2. A method for detecting neutralization of a concrete structure by burying a plurality of electrodes in a concrete structure to be measured and measuring a potential difference between the plurality of electrodes via concrete of the structure. A method for detecting neutralization of a concrete structure, wherein the electrode is made of a metal element belonging to Group 5 of the periodic table or an alloy having at least one of the metal elements as a base.
ビスマス又はアンチモンであることを特徴とする請求項
１又は２記載のコンクリート構造体の中性化検出方法。3. The method for detecting neutralization of a concrete structure according to claim 1, wherein the metal element belonging to Group 5 of the periodic table is bismuth or antimony.
金属元素の１種以上を基体とする合金からなる前記電極
が、前記金属元素の酸化皮膜又は水酸化皮膜を有するこ
とを特徴とする請求項１〜３のいずれか１項に記載のコ
ンクリート構造体の中性化検出方法。4. The electrode comprising a metal element belonging to Group 5 of the periodic table or an alloy having at least one of the metal elements as a base has an oxide film or a hydroxide film of the metal element. The method for detecting neutralization of a concrete structure according to claim 1.
るコンクリートの中性化検出センサにおいて、周期律表
第５族に属する金属元素又は該金属元素の１種以上を基
体とする合金からなる測定電極及び照合電極を、少なく
ともその一部が露出するように絶縁体に支持又は埋設
し、前記電極を電位差測定計と電気的に接続する手段を
設け、該構造体のコンクリートを介した該測定電極と該
照合電極との間の電位差を計測可能にしたことを特徴と
するコンクリート構造体の中性化検出センサ。5. A neutralization detection sensor for concrete embedded in a concrete structure to be measured, wherein the measurement electrode is made of a metal element belonging to Group 5 of the periodic table or an alloy containing at least one of the metal elements as a base. And the reference electrode is supported or buried in an insulator so that at least a part of the electrode is exposed, and means for electrically connecting the electrode to a potentiometer is provided. A neutralization detection sensor for a concrete structure, wherein a potential difference between the reference electrode and the reference electrode can be measured.
るコンクリートの中性化検出センサにおいて、周期律表
第５族に属する金属元素又は該金属元素の１種以上を基
体とする合金からなる電極を複数用意し、各電極の少な
くともその一部が露出するように絶縁体に支持又は埋設
し、前記複数の電極をそれぞれ電位差測定計と電気的に
接続する手段を設け、該構造体のコンクリートを介し、
前記電極間の電位差を計測可能にしたことを特徴とする
コンクリート構造体の中性化検出センサ。6. A neutralization detection sensor for concrete buried in a concrete structure to be measured, comprising an electrode made of a metal element belonging to Group 5 of the periodic table or an alloy having at least one of the metal elements as a base. A plurality of the electrodes are supported or buried in an insulator so that at least a part of each electrode is exposed, and means for electrically connecting each of the plurality of electrodes to a potentiometer is provided. ,
A neutralization detection sensor for a concrete structure, wherein a potential difference between the electrodes can be measured.
ビスマス又はアンチモンであることを特徴とする請求項
５又は６記載のコンクリート構造体の中性化検出セン
サ。7. The neutralization detection sensor according to claim 5, wherein the metal element belonging to Group 5 of the periodic table is bismuth or antimony.
金属元素の１種以上を基体とする合金からなる前記電極
が、前記金属元素の酸化皮膜又は水酸化皮膜を有するこ
とを特徴とする請求項５〜７のいずれか１項に記載のコ
ンクリート構造体の中性化検出センサ。8. The electrode comprising a metal element belonging to Group 5 of the Periodic Table or an alloy having at least one of the metal elements as a base has an oxide film or a hydroxide film of the metal element. The neutralization detection sensor for a concrete structure according to any one of claims 5 to 7.
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| JP19455298A JP3911092B2 (en) | 1998-07-09 | 1998-07-09 | Neutralization detection method and neutralization detection sensor for concrete structure |
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| JP19455298A JP3911092B2 (en) | 1998-07-09 | 1998-07-09 | Neutralization detection method and neutralization detection sensor for concrete structure |
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| JP2002038723A (en) * | 2000-07-26 | 2002-02-06 | Suzuko Oshita | Real time life cycle maintenance method of steel frame/ reinforced concrete constructed building |
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