JPH0814550B2 - Concrete resistivity measurement method - Google Patents
Concrete resistivity measurement methodInfo
- Publication number
- JPH0814550B2 JPH0814550B2 JP62297781A JP29778187A JPH0814550B2 JP H0814550 B2 JPH0814550 B2 JP H0814550B2 JP 62297781 A JP62297781 A JP 62297781A JP 29778187 A JP29778187 A JP 29778187A JP H0814550 B2 JPH0814550 B2 JP H0814550B2
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- concrete
- resistivity
- reinforcing bar
- measuring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000004567 concrete Substances 0.000 title claims description 48
- 238000000691 measurement method Methods 0.000 title 1
- 230000003014 reinforcing effect Effects 0.000 claims description 37
- 238000000034 method Methods 0.000 claims description 28
- 239000002689 soil Substances 0.000 description 11
- 238000005259 measurement Methods 0.000 description 9
- 230000007797 corrosion Effects 0.000 description 8
- 238000005260 corrosion Methods 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000010287 polarization Effects 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000011150 reinforced concrete Substances 0.000 description 3
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000008151 electrolyte solution Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical class [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、強化コンクリート（RC）構造物の塩害等に
よる影響を把握するうえで重要なパラメータであるコン
クリートの抵抗率の測定方法に関する。The present invention relates to a method for measuring the resistivity of concrete, which is an important parameter for grasping the influence of salt damage etc. on reinforced concrete (RC) structures.
［従来の技術］ コンクリートの抵抗率を知ることは、コンクリート中
の鉄筋の塩害等による腐食の予測・診断などを行なうう
えで極めて有益である。[Prior Art] Knowing the resistivity of concrete is extremely useful for predicting and diagnosing corrosion due to salt damage of reinforcing bars in concrete.
ところで従来、土壌の抵抗率を測定する方法として
は、例えば「電食・土壌腐食ハンドブック」（電気学
会、コロナ社）に見られるように、土壌杖を用いて局部
的な土壌の抵抗率を測る方法や平均値的な土質の抵抗率
を測定する４電極法が知られている。By the way, conventionally, as a method for measuring the resistivity of soil, as shown in, for example, "Handbook of Electrolytic Corrosion / Soil Corrosion" (The Institute of Electrical Engineers of Japan, Corona Co.), the local resistivity of soil is measured using a soil cane. The method and the four-electrode method for measuring the average soil resistivity are known.
土壌杖を用いる方法とは、一方の電極である６角鉄柱
の先端にこれと絶縁された他方の鉄電極を取り付けた土
壌杖を土壌中に突きさして、両電極間の抵抗値を測定
し、突きさした部分の土壌の抵抗率を簡易に測定する方
法である。The method of using a soil cane is to stick a soil cane, in which the other iron electrode insulated from this is attached to the tip of a hexagonal iron pole that is one electrode, into the soil, and measure the resistance value between both electrodes, It is a method of simply measuring the resistivity of the soil in the pointed part.
また、４電極法には直流電源を用いる場合と交流電流
を用いる場合とがあるが、いずれの場合も４つの電極を
地表面の一直線上に等間隔で配置して両側の２電極間に
電流を流し、中間の２電極間の電位差を測定して抵抗率
を求めるものである。In the four-electrode method, there are cases where a direct current power source is used and cases where an alternating current is used. In either case, four electrodes are arranged on a straight line on the ground surface at equal intervals and a current is applied between the two electrodes on both sides. Is flowed and the potential difference between the two middle electrodes is measured to obtain the resistivity.
［発明が解決しようとする問題点］ しかしながら、土壌杖法は被測定物質に突きさすこと
が必要であるため硬いコンクリートに適用することはで
きない。[Problems to be Solved by the Invention] However, the soil cane method cannot be applied to hard concrete because it needs to stick to the substance to be measured.
また、４電極法は、被測定物質中の既設の埋設物の影
響を交流では特に強く受けるため、鉄筋を含むコンクリ
ート構造物のコンクリート等の測定には適さない。また
直流電源を用いた場合、コンクリートのような表面が乾
燥していることが多いものを測定するには電流を流すの
に高電圧を要するため危険である。例えば乾燥したコン
クリートの場合、最大200V印加可能な定電流装置を用い
ても安定した電流は得られない。このとき、電流を安定
させるため電極の先端が接触するコンクリート表面を湿
潤状態にすると、電極間隔が短い（２〜10cm）ため、今
度は逆に表面の水分によって電極間が短絡してしまい、
コンクリート内部の抵抗率を測定することができないと
いう問題を生ずる。さらにまた、電位検出用の電極は本
来電極電位が同じでなければならないが、実際は銅のよ
うな同一金属棒を用いているだけであるため、両電極間
の自然電位差の分だけ誤差が入るという問題もある。Further, the four-electrode method is particularly not suitable for measuring concrete or the like in a concrete structure including a reinforcing bar because the influence of an existing buried object in the substance to be measured is particularly strongly affected by the alternating current. Further, when a DC power source is used, it is dangerous to measure a current such as concrete whose surface is often dry, because a high voltage is required to pass an electric current. For example, in the case of dry concrete, a stable current cannot be obtained even if a constant current device capable of applying a maximum of 200 V is used. At this time, if the concrete surface with which the tips of the electrodes come into contact is made wet in order to stabilize the current, the electrode interval is short (2-10 cm), so this time conversely short-circuits between the electrodes due to surface moisture,
The problem arises that the resistivity inside the concrete cannot be measured. Furthermore, the electrodes for potential detection should originally have the same electrode potential, but since the same metal rod such as copper is actually used, there is an error due to the natural potential difference between both electrodes. There are also problems.
このようにコンクリートの抵抗率の測定方法は従来得
られていない。As described above, a method for measuring the resistivity of concrete has not been obtained hitherto.
本発明の目的は、このような従来技術の問題点に鑑
み、鉄筋やコンクリート表面の乾湿に影響されず安定し
てコンクリート内部の抵抗率が測定できる簡便な抵抗率
測定方法を提供することにある。An object of the present invention is to provide a simple resistivity measuring method capable of stably measuring the resistivity inside the concrete without being affected by the dryness and humidity of the reinforcing bar and the concrete surface in view of the problems of the conventional art. .
［問題点を解決するための手段］ 上記目的を達成するため本発明では、コンクリート表
面に取り付けた１以上の電極と、コンクリート中の鉄筋
間に電流を流して該電極および鉄筋間の抵抗値を計測
し、該抵抗値に基づきコンクリートの抵抗率を求めるよ
うにしている。[Means for Solving the Problems] In order to achieve the above object, in the present invention, an electric current is passed between one or more electrodes attached to a concrete surface and a reinforcing bar in the concrete to reduce the resistance value between the electrodes and the reinforcing bar. The resistivity of concrete is measured and measured based on the resistance value.
前記電極および鉄筋間の抵抗値は、例えば、該電極お
よび鉄筋間に高周波の交流電流を定電流で流し、このと
きのコンクリート表面の照合電極と鉄筋間の電位応答に
基づき計測することができる。高周波交流電流の波形に
ついては、サイン波、矩形波、三角波、鋸歯状波など種
々あるが、規則性のある波形であればその形状は問わな
い。The resistance value between the electrode and the reinforcing bar can be measured, for example, by applying a high-frequency alternating current between the electrode and the reinforcing bar at a constant current and measuring the potential response between the reference electrode and the reinforcing bar on the concrete surface at this time. The high-frequency alternating current has various waveforms such as a sine wave, a rectangular wave, a triangular wave, and a sawtooth wave, but the shape is not limited as long as it has regularity.
また、前記１以上の電極は例えば鉄筋腐食モニタリン
グ手法において自然電位や分極抵抗を測定する際に用い
られる、電極および照合電極を備えたセンサの電極を利
用することができる。Further, as the one or more electrodes, for example, an electrode of a sensor provided with an electrode and a reference electrode, which is used when measuring a self-potential or a polarization resistance in a reinforcing bar corrosion monitoring method, can be used.
［作用］ この構成において、鉄筋は被測定物質内部にあること
からコンクリート表面の電極と鉄筋間に流れる電流はコ
ンクリート内部を流れるため、コンクリート表面が湿潤
していても従来例のような短絡の問題なく安定した測定
が行なわれる。また、例えば、塩害の影響を受けたRC構
造物のように塩分濃度が表層において大きく内部に入る
に従って減少するような場合は、表面を湿潤状態に保っ
たとき表層の抵抗は急激に減少し内部ほど抵抗率が高く
なる。この場合、等価回路的にはコンクリート表面から
内部に入るに従って増大する抵抗がシリーズにつながっ
ていると考えられ、鉄筋腐食に直接的に係る鉄筋近傍の
抵抗率が大きく反映された抵抗率が測定されることにな
る。一方、前記測定抵抗値から抵抗率を求める関係式の
定式化は、一般には境界条件が複雑なためほとんど行な
われていないが、本発明の方法においては、鉄筋を例え
ば平板状あるいは棒状の電極というように、比較的単純
なパターンにモデル化して考えることにより可能ならし
めている。さらに、前記測定される抵抗値として、電極
と照合電極とを含んで構成されるセンサを用いて自然電
位や分極抵抗を測定する鉄筋腐食モニタリング手段にお
いて測定される鉄筋とセンサ間の抵抗値を用いることが
でき、この場合は他の装置を追加する必要なく抵抗率の
測定が行われる。また、このように照合電極を基準とし
た場合、自然電位による誤差なく測定される。[Operation] In this configuration, since the rebar is inside the substance to be measured, the current flowing between the electrode on the concrete surface and the rebar flows inside the concrete, so that even if the concrete surface is wet, the problem of short circuit as in the conventional example occurs. Stable measurement is performed without Also, for example, in the case of RC structures affected by salt damage, where the salt concentration greatly decreases as it enters the surface layer, the resistance of the surface layer decreases sharply when the surface is kept wet, and The higher the resistivity, the higher. In this case, in terms of an equivalent circuit, it is considered that the resistance increases as it enters from the concrete surface into the series, and the resistivity that directly reflects the corrosion in the vicinity of the rebar is directly measured. Will be. On the other hand, the formulation of the relational expression for obtaining the resistivity from the measured resistance value is generally hardly performed because the boundary condition is complicated, but in the method of the present invention, the reinforcing bar is referred to as, for example, a flat plate-shaped or rod-shaped electrode. As described above, it is possible by modeling into a relatively simple pattern. Further, as the measured resistance value, the resistance value between the reinforcing bar and the sensor, which is measured by the reinforcing bar corrosion monitoring means for measuring the spontaneous potential or the polarization resistance using the sensor including the electrode and the reference electrode, is used. In this case, the resistivity measurement is performed without the need for adding another device. Further, when the reference electrode is used as a reference in this way, measurement is performed without error due to the natural potential.
［実施例］ 以下、図面を用いて本発明の実施例を説明する。Embodiments Embodiments of the present invention will be described below with reference to the drawings.
コンクリートの分極抵抗測定の際、コンクリート表面
上に置いたセンサの電極と鉄筋間の１次電流分布はマク
ロ的には、鉄筋間隔ｌとかぶり厚さｈとの関係が l/h≦４のときは電極と平板間における分布、 l/h＞４のときは電極と１本の鉄筋間における分布 として考えられる。したがって、この，の場合にお
ける極間抵抗の式を抵抗率ρの関数として求めておけ
ば、極間抵抗Rsの測定値から抵抗率ρを算出することが
できる。When measuring the polarization resistance of concrete, the primary current distribution between the sensor electrode placed on the concrete surface and the reinforcing bar is macroscopically when the relationship between the reinforcing bar interval l and the cover thickness h is l / h ≤ 4. Is considered to be the distribution between the electrode and the plate, and when l / h> 4, it is considered to be the distribution between the electrode and one rebar. Therefore, if the formula of the inter-electrode resistance in this case is obtained as a function of the resistivity ρ, the resistivity ρ can be calculated from the measured value of the inter-electrode resistance R s .
第１図は、上記の場合を示す模式図である。 FIG. 1 is a schematic diagram showing the above case.
同図のように、平板とみなされた鉄筋群（以下、平板
という）１上のコンクリート２のかぶり厚さをｈ、コン
クリート２表面上の円盤電極（センサ）３の直径をａ、
コンクリート２の抵抗率をρとし、円盤電極３と平板１
間の抵抗（極間抵抗）Rsが Rs＝Ｃρiajhk （１） （C,i,j,k:定数） で表わせるとすれば、この（１）式の各量の基本単位で
ある（Ω）を〔Ｒ〕、（cm）を〔Ｌ〕で表わして次元式
をつくると、Rs＝〔Ｒ〕，ρ＝〔Ｒ〕〔Ｌ〕,a＝
〔Ｌ〕,h＝〔Ｌ〕であるから、（１）式から、 〔Ｒ〕＝Ｃ（〔Ｒ〕〔Ｌ〕）ｉ〔Ｌ〕ｊ〔Ｌ〕ｋ（２） となる。この（２）式において各基本単位について両辺
の次元は一致しなければならないので、 ｉ＝１ （３） ｊ＝−ｋ−１ （４） が成り立つ。この（３），（４）式を（１）式に代入し
両辺の対数をとれば、 log（Rs・a/ρ）＝logC＋klog（h/a） （５） となる。したがって、種々のa,hにおいてRsを求め、log
（h/a）とlog（Rs・a/ρ）との関係をプロットすれば、
その直線の傾きよりｋ、切片よりＣ、（４）式よりｊが
求まり式（１）が完成する。As shown in the same figure, the cover thickness of concrete 2 on a reinforcing bar group (hereinafter referred to as a flat plate) 1 regarded as a flat plate is h, the diameter of a disk electrode (sensor) 3 on the concrete 2 surface is a,
Let ρ be the resistivity of concrete 2 and disk electrode 3 and flat plate 1
If the resistance between electrodes (resistance between poles) R s can be expressed by R s = Cρ i a j h k (1) (C, i, j, k: constant), When a dimensional equation is created by expressing (Ω) which is a basic unit as [R] and (cm) as [L], R s = [R], ρ = [R] [L], a =
Since [L], h = [L], from the formula (1), [R] = C ([R] [L]) i [L] j [L] k (2). In this equation (2), the dimensions of both sides must match for each basic unit, so that i = 1 (3) j = -k-1 (4). Substituting equations (3) and (4) into equation (1) and taking the logarithm of both sides, log (Rs · a / ρ) = logC + klog (h / a) (5). Therefore, we obtain R s for various a and h, and log
If you plot the relationship between (h / a) and log (R s · a / ρ),
From the slope of the straight line, k is obtained, C is obtained from the intercept, and j is obtained from the equation (4) to complete the equation (1).
なお、ここでは照合電極を用いずに、円盤電極３と鉄
筋との間の極間抵抗値を得ているが、実構造物における
測定では、ゲル化された飽和塩化カリウム水溶液中（低
抵抗率環境）に対極と照合電極を配置して構成したセン
サをコンクリート表面に配置し、この対極と鉄筋との間
に高周波の交流電流を定電流で流し、照合電極と鉄筋と
の間の電位応答に基づいて極間抵抗が計測される。この
ようにして計測される抵抗値は、定抵抗率環境において
対極と照合電極とが近接しているため、対極・鉄筋間に
おける極間抵抗とほぼ等しく、計測によるセンサ内にお
ける電圧降下は無視できるほどに小さい。すなわち、こ
こでは、センサの先端（コンクリート接触部）の円形形
状部分を模擬した円盤電極３を用い、これと鉄筋間の極
間抵抗を計測しており、照合電極を無視した計測を行っ
ている。In addition, here, the electrode-to-electrode resistance value between the disk electrode 3 and the reinforcing bar is obtained without using the reference electrode. However, in the measurement of the actual structure, it was measured in a gelled saturated potassium chloride aqueous solution (low resistivity). (Environment), a sensor configured by arranging a counter electrode and a reference electrode is placed on the concrete surface, and a high-frequency alternating current is passed as a constant current between the counter electrode and the rebar to make the potential response between the reference electrode and the rebar. The inter-electrode resistance is measured based on this. The resistance value measured in this way is almost equal to the resistance between the counter electrode and the rebar between the counter electrode and the reference electrode in the constant resistivity environment, and the voltage drop in the sensor due to the measurement can be ignored. So small. That is, here, the disc electrode 3 simulating the circular portion of the tip (concrete contact portion) of the sensor is used, and the inter-electrode resistance between this and the rebar is measured, and the measurement is performed without the reference electrode. .
一方、前記の場合は第２図に示すように、コンクリ
ート２中の鉄筋４の直径をＤとし、かぶり厚さ、円盤電
極３の直径およびコンクリート２の抵抗率を上記と同じ
くh,aおよびρとし、円盤電極３と１本の鉄筋４間の抵
抗Rsが Rs＝ＣρiajhkDn （６） （C,i,j,k,n:定数） で表わせるとすれば、上述同様にして、 ｉ＝１ （７） ｎ＝−ｊ−ｋ−１ （８） が得られ、この（７），（８）式を（６）式に代入し両
辺の対数をとると、 log（RsD/ρ）＝logC＋jlog（a/D） ＋klog（h/D） （９） となる。したがって、a/D＝一定の条件下におけるlog
（h/D）とlog（RsD/ρ）との関係を示す直線の傾きより
ｋが求まり、h/D＝一定の条件下におけるlog（a/D）
と、log（RsD/ρ）間の関係を示す直線の傾きよりｊが
求まる。On the other hand, in the above-mentioned case, as shown in FIG. 2, the diameter of the reinforcing bar 4 in the concrete 2 is D, and the covering thickness, the diameter of the disk electrode 3 and the resistivity of the concrete 2 are the same as above. If the resistance R s between the disk electrode 3 and one rebar 4 can be expressed by R s = Cρ i a j h k D n (6) (C, i, j, k, n: constant) , I = 1 (7) n = -jk-1 (8) is obtained in the same manner as described above, and when these equations (7) and (8) are substituted into equation (6) and the logarithm of both sides is taken, , Log (R s D / ρ) = logC + jlog (a / D) + klog (h / D) (9). Therefore, a / D = log under constant conditions
(H / D) and log (R s D / ρ) can be calculated from the slope of the straight line, and h / D = log (a / D) under constant conditions
And j can be obtained from the slope of a straight line indicating the relationship between log (R s D / ρ).
第３図（ａ），（ｂ）は前記論理に基づき前記の場
合における（１）式の各定数を決めるため極間抵抗を実
験的に測定する様子を示す平面図および正面図である。3 (a) and 3 (b) are a plan view and a front view showing how the inter-electrode resistance is experimentally measured in order to determine each constant of the equation (1) based on the above logic.
同図に示すように460×500mmの軟鋼平板（裏面シー
ル）５上に高さhcm、抵抗率ρ（＝4237Ω・cm（23.5
℃））の水かぶり６を設け、平板５の中央部直上に側面
をシールした直径acmの円盤電極７をセットし、そして
軟鋼平板５と円盤電極７との間に1kHzのサイン波を印加
してこの両極間のインピーダンスＺをインピーダンスメ
ータ８で測定し、その実数部（Re（Ｚ））を極間抵抗Rs
とする。なお、本系の測定においては電流分布は電解液
抵抗率に依存しない一次分布であるため電解液は水道水
を用いた。As shown in the figure, the height hcm and resistivity ρ (= 4237Ω · cm (23.5
℃)), and a disk electrode 7 with a diameter of acm whose side is sealed is set just above the center of the flat plate 5, and a 1 kHz sine wave is applied between the mild steel flat plate 5 and the disk electrode 7. The impedance Z between the levers is measured with an impedance meter 8, and the real part (Re (Z)) is measured as the resistance R s between the electrodes.
And In the measurement of this system, the current distribution is a primary distribution that does not depend on the electrolytic solution resistivity, so tap water was used as the electrolytic solution.
ａおよびｈの値を ａ＝1,2,3,4,5〔cm〕 ｈ＝1,2,3,4,5,6,7,8,9,10〔cm〕 としたすべてのa,hの組合せ（50通り）について測定
し、（５）式に基づいてプロットしたところ、第４図に
示すグラフが得られた。同図中の直線ＡおよびＢは全デ
ータをh/a＜１のグループとh/a≧１のグループとに分類
し、それぞれのグループにおいて最小二乗法により１次
回帰した結果を示す。各データはほぼ直線ＡまたはＢ上
に乗っており、h/a＝１を境にして２つのグループに分
けるならば、Rsとρとの関係は（１）式で表わせること
がわかる。The values of a and h are a = 1,2,3,4,5 [cm] h = 1,2,3,4,5,6,7,8,9,10 [cm] When the combinations of h (50 ways) were measured and plotted based on the equation (5), the graph shown in FIG. 4 was obtained. Lines A and B in the figure show the results of first-order regression by the least-squares method in which all the data are classified into groups of h / a <1 and groups of h / a ≧ 1. It is understood that each data is on the straight line A or B, and if h / a = 1 is used as a boundary and divided into two groups, the relation between R s and ρ can be expressed by the equation (1).
一方、前記の場合については、第５図に示すよう
に、560×800×500mmの水槽９の底面より30cmの高さの
位置に鉄筋として10φ×800mmの丸鋼10をセットし、こ
の丸鋼10の上端部を基準としてhcmの高さで抵抗率が454
5Ω・cm（23.2℃）の水かぶり６を設定して、上記と同
様にして、丸鋼10中央部直上の水面に位置する直径acm
の円盤電極７と丸鋼10との間の極間抵抗Rsを1kHzのサイ
ン波を印加したときのRe（Ｚ）として計測する。On the other hand, in the case of the above, as shown in FIG. 5, a round steel 10 of 10φ × 800 mm is set as a reinforcing bar at a position 30 cm above the bottom of the water tank 9 of 560 × 800 × 500 mm. The resistivity is 454 at hcm height based on the upper end of 10
A water cover 6 of 5 Ω · cm (23.2 ° C) was set, and in the same manner as above, the diameter acm located on the water surface directly above the center of the round steel 10
The inter-electrode resistance R s between the disk electrode 7 and the round steel 10 is measured as Re (Z) when a sine wave of 1 kHz is applied.
ａ＝1,2,3,3.5,4,4.5,5〔cm〕 ｈ＝1,2,3,4,5,6,7,8,9,10〔cm〕 としたすべてのa,hおよびＤ（＝10mm）の組合せ（70通
り）について測定し、（９）式に従い、h/D＝一定のも
とでlog（a/D）とlog（RsD/ρ）との関係をプロットし
たところ第６図に示すグラフが得られた。また、a/D＝
一定のもとでlog（h/D）とlog（RsD/ρ）との関係をプ
ロットしたところ第７図に示すグラフが得られた。a = 1,2,3,3.5,4,4.5,5 [cm] h = 1,2,3,4,5,6,7,8,9,10 [cm] all a, h and Measured for 70 combinations of D (= 10 mm), and plot the relationship between log (a / D) and log (R s D / ρ) under the condition of h / D = constant according to equation (9). As a result, the graph shown in FIG. 6 was obtained. Also, a / D ＝
When the relationship between log (h / D) and log (R s D / ρ) was plotted under a constant condition, the graph shown in FIG. 7 was obtained.
両図ともそれぞれのパラメータh/D,a/Dを一定の値に
固定した場合において良い直線近似が可能であるが、こ
れらのパラメータの変化にともない傾きj,kが若干変化
する。j,kの取り扱い方法として、第６および７図に示
すようにｊの場合h/Dを、ｋの場合a/Dをそれぞれ３つの
領域に区分けし、各領域の平均値をその領域における値
とした。j,kの値が求まったことによりｎの値はh/Dとa/
Dの２次元領域において（８）式より求められる。得ら
れるべき数をもとにすれば、Ｃ値については第６図およ
び第７図の各直線の切片より各パラメータにおけるＣ値
が求まる。第１表に示すように、求められたＣ値を先の
h/D,a/Dの２次元領域に書き出し、各領域で平均したも
のをその領域のＣ値とした。In both figures, a good linear approximation is possible when the respective parameters h / D and a / D are fixed to constant values, but the slopes j and k change slightly with changes in these parameters. As shown in Figs. 6 and 7, h / D for j and k for a and D are divided into three areas, and the average value of each area is the value in that area. And Since the values of j and k are obtained, the value of n is h / D and a /
It is obtained from the equation (8) in the two-dimensional area of D. Based on the number to be obtained, the C value for each parameter can be obtained from the intercept of each straight line in FIGS. 6 and 7. As shown in Table 1, the calculated C value is
It is written in a two-dimensional area of h / D and a / D, and the average of each area is taken as the C value of that area.
以上の結果をもとに各パラメータを整理して求めた極
間抵抗値Rsより抵抗率ρを算出する式を第２表に示す。
この式は一見複雑そうにみえるが、パソコン等を用い、
測定されたRsおよび各種境界条件をインプットすること
によってρを容易に算出することができる。Table 2 shows the formula for calculating the resistivity ρ from the inter-electrode resistance value R s obtained by organizing each parameter based on the above results.
This formula looks complicated at first glance, but using a personal computer,
Ρ can be easily calculated by inputting the measured R s and various boundary conditions.
第８図は、第２表の式を用いて抵抗率を実験的に測定
する方法を説明するための説明図である。ここでは水層
11中に鉄筋として16φの丸鋼12を格子状に配置し、コン
クリートを模擬した水道水13を、上部鉄筋12aの上端部
を基準としてhcmの水かぶりの状態に設定してある。そ
して、鉄筋直上の水面にセンサの電極を模擬した直径ac
mの円盤電極14をセットし、鉄筋12と円盤電極14間の極
間抵抗を1kHzのサイン波に対するRe（Ｚ）として測定し
た。ただし、このとき、各丸鋼12間の電気的導通を確実
にするために、それぞれの丸鋼からリード線を立ち上げ
てターミナルにて短絡させて測定した。また、前記鉄筋
直上としては、鉄筋交差部、上部鉄筋12aに沿って下部
鉄筋間隔l1の1/4および1/2の位置、さらに下部鉄筋12b
に沿って上部鉄筋間隔l2の1/4および1/2の位置の計５カ
所を選定した。従って試験に供された幾何学的条件は、 ａ＝1,2,3,4,5〔cm〕 ｈ＝2,4,6,8,10〔cm〕 l1＝l2＝10,20,30〔cm〕 のすべての組合せに、センサ設置位置の５ケ所を加えた
375通りである。 FIG. 8 is an explanatory diagram for explaining a method of experimentally measuring the resistivity using the formula in Table 2. Here water layer
Round steel 12 having a diameter of 16 φ is arranged in a grid shape in 11 and tap water 13 simulating concrete is set in a water-blown state of hcm with reference to the upper end of the upper reinforcing bar 12a. Then, the diameter ac simulating the sensor electrode on the water surface directly above the rebar
The disk electrode 14 of m was set, and the interelectrode resistance between the reinforcing bar 12 and the disk electrode 14 was measured as Re (Z) for a sine wave of 1 kHz. However, at this time, in order to ensure electrical conduction between the round bars 12, the lead wire was raised from each round bar and short-circuited at the terminal for measurement. Further, as directly above the reinforcing bar, a reinforcing bar intersection, a position of 1/4 and 1/2 of the lower reinforcing bar interval l 1 along the upper reinforcing bar 12a, and further the lower reinforcing bar 12b.
A total of 5 locations were selected along the line, 1/4 and 1/2 of the upper rebar spacing l 2 . Therefore, the geometrical conditions used in the test are as follows: a = 1,2,3,4,5 [cm] h = 2,4,6,8,10 [cm] l 1 = l 2 = 10,20, Five sensor installation positions were added to all combinations of 30 [cm].
There are 375 streets.
このようにして計測されたRsを第２表の式によって抵
抗率（ρcal）に換算し別途電導度計にて求められた槽
中の水の抵抗率（ρobs）と比較した結果を両者の比
（ρcal/ρobs）として第９図に示す。The R s measured in this way was converted into the resistivity (ρ cal ) by the formula in Table 2 and the result was compared with the resistivity (ρ obs ) of the water in the tank, which was separately obtained by the conductivity meter. The ratio (ρ cal / ρ obs ) of both is shown in FIG.
同図に示すように、l/h＞４においては境界条件によ
って値に若干のばらつきが認められるが、使用用途がコ
ンクリートの抵抗率の評価という目的から考えるなら
ば、おおむね良好な結果を示したと判断することができ
る。As shown in the figure, when l / h> 4, there are some variations in the values depending on the boundary conditions. However, if the purpose of use is to evaluate the resistivity of concrete, it is said that the results were generally good. You can judge.
なお、本発明の方法はコンクリートに限らず土壌、海
水、淡水などの電解質等の抵抗率測定にも用いることが
できる。The method of the present invention can be used not only for concrete but also for measuring the resistivity of soil, seawater, fresh water, and other electrolytes.
［発明の効果］ 以上説明したように、本発明によれば、鉄筋自身を他
方の電極として用いるため、鉄筋の影響なくかつコンク
リート表面の乾湿にも関係なく安定した測定が簡単に行
なえる。また、鉄筋近傍の抵抗率すなわち鉄筋の腐食に
直接係り従来測定容易でなかったコンクリート内部の抵
抗率が反映された抵抗率を測定することができる。さら
に、コンクリート構造物の鉄筋等の分極抵抗法による腐
食モニタリング等に際して他の装置を追加する必要なく
同時に測定することができる。[Effects of the Invention] As described above, according to the present invention, since the reinforcing bar itself is used as the other electrode, stable measurement can be easily performed without being affected by the reinforcing bar and regardless of whether the concrete surface is wet or dry. Further, it is possible to measure the resistivity in the vicinity of the reinforcing bar, that is, the resistivity directly reflecting the corrosion of the reinforcing bar and reflecting the resistivity inside the concrete, which was not easy to measure in the past. Furthermore, it is possible to simultaneously measure the corrosion of the concrete structure such as the reinforcing bar by the polarization resistance method without the need for adding another device.
第１図は、本発明の抵抗率測定方法においてパターン化
された１つのモデルにおける幾何学的パラメータを示す
模式図、 第２図は、本発明の抵抗率測定方法においてパターン化
された他のモデルにおける幾何学的パラメータを示す模
式図、 第３図（ａ），（ｂ）は、第１図に示したパラメータを
有する極間抵抗と抵抗率の関係式（極間抵抗式）を求め
るため抵抗率が既知の物質の極間抵抗を測定する実験を
示す平面図および正面図、 第４図は、第３図に示した方法で測定した結果を示すと
ともにこれに基づき極間抵抗式の考察を行なうための両
対数グラフ、 第５図（ａ），（ｂ）は、第２図に示したパラメータを
有する極間抵抗と抵抗率の関係式（極間抵抗式）を求め
るため抵抗率が既知の物質の極間抵抗を測定する実験を
示す平面図および正面図、 第６および７図は、第５図に示した方法で測定した結果
を示すとともにこれに基づき極間抵抗式の考察を行なう
ための両対数グラフ、 第８図は、求められた極間抵抗式を用いて抵抗率を実験
的に測定する方法を説明するための説明図、そして 第９図は、第８図を用いて説明した方法により抵抗率を
測定した結果を示すグラフである。 1:平板、 2:コンクリート、 3,7,14:円盤電極、 4:1本の鉄筋、 5:軟鋼平板、 6:水かぶり、 8:インピーダンスメータ、 9,11:水槽、 10,12:丸鋼（鉄筋）。FIG. 1 is a schematic diagram showing geometrical parameters in one model patterned in the resistivity measuring method of the present invention, and FIG. 2 is another model patterned in the resistivity measuring method of the present invention. 3 (a) and 3 (b) are schematic diagrams showing geometrical parameters in FIG. 3 are used to obtain a relational expression (inter-electrode resistance expression) between the inter-electrode resistance and the resistivity having the parameters shown in FIG. FIG. 4 is a plan view and a front view showing an experiment for measuring the inter-electrode resistance of a substance having a known rate, and FIG. 4 shows the results measured by the method shown in FIG. The logarithmic graph for carrying out, FIGS. 5 (a) and 5 (b), the resistivity is known in order to obtain the relational expression (inter-electrode resistance equation) between the inter-electrode resistance and the resistivity having the parameters shown in FIG. Plan view showing an experiment to measure the inter-electrode resistance of various materials and And a front view, FIGS. 6 and 7 show the results measured by the method shown in FIG. 5, and a logarithmic log graph for considering the interelectrode resistance formula based on the results, and FIG. 8 were obtained. Explanatory drawing for explaining the method of experimentally measuring the resistivity using the inter-electrode resistance formula, and FIG. 9 is a graph showing the results of measuring the resistivity by the method described with reference to FIG. is there. 1: Flat plate, 2: Concrete, 3,7,14: Disc electrode, 4: 1 rebar, 5: Mild steel flat plate, 6: Water cover, 8: Impedance meter, 9,11: Water tank, 10,12: Round Steel (rebar).
Claims (4)
極とコンクリート中の鉄筋間に電流を流して該電極およ
び鉄筋間の抵抗値を計測し、該抵抗値に基づきコンクリ
ートの抵抗率を求めることを特徴とするコンクリートの
抵抗率測定方法。1. A method for measuring a resistance value between an electrode and a reinforcing bar in a concrete by applying an electric current between one or more electrodes attached to the surface of the concrete and the reinforcing bar in the concrete, and determining the resistivity of the concrete based on the resistance value. Characteristic measuring method for resistivity of concrete.
極と鉄筋との距離、該電極の大きさおよび鉄筋間隔また
はこれに加えて鉄筋の太さをパラメータとして含む前記
抵抗値と抵抗率との関係より求める、特許請求の範囲第
１項記載のコンクリートの抵抗率測定方法。2. The resistivity is defined by a distance between an electrode on the concrete surface and a reinforcing bar, a size of the electrode and a reinforcing bar interval or in addition to the resistance value and a resistivity including the thickness of the reinforcing bar as parameters. The method for measuring the resistivity of concrete according to claim 1, which is obtained from the relationship.
備えたセンサの電極である、特許請求の範囲第２項記載
のコンクリートの抵抗率測定方法。3. The method for measuring the resistivity of concrete according to claim 2, wherein the one or more electrodes are electrodes of a sensor having an electrode and a reference electrode.
極および鉄筋間に高周波の交流電流を定電流で流し、こ
のときの前記照合電極と鉄筋間の電位応答に基づき計測
する、特許請求の範囲第３項記載のコンクリートの抵抗
率測定方法。4. The resistance value is measured based on a potential response between the reference electrode and the reinforcing bar when a high-frequency alternating current is passed as a constant current between the electrode on the concrete surface and the reinforcing bar. The method for measuring the resistivity of concrete according to item 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62297781A JPH0814550B2 (en) | 1987-11-27 | 1987-11-27 | Concrete resistivity measurement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62297781A JPH0814550B2 (en) | 1987-11-27 | 1987-11-27 | Concrete resistivity measurement method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01141346A JPH01141346A (en) | 1989-06-02 |
| JPH0814550B2 true JPH0814550B2 (en) | 1996-02-14 |
Family
ID=17851096
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62297781A Expired - Lifetime JPH0814550B2 (en) | 1987-11-27 | 1987-11-27 | Concrete resistivity measurement method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0814550B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10318145B3 (en) * | 2003-04-18 | 2004-11-18 | Mathias Fritzenwenger | Instrument measuring moisture in building materials, especially in screeds, includes embedded probe connected with instrument measuring resistance |
| CN102269725B (en) * | 2011-05-10 | 2012-10-31 | 交通运输部公路科学研究所 | A device and method for testing the uniformity and compactness of concrete pouring |
| CN119846311A (en) * | 2024-09-18 | 2025-04-18 | 国网天津市电力公司电力科学研究院 | Resistivity measuring device and method for reinforced concrete pole, electronic equipment and storage medium |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61111401A (en) * | 1984-11-06 | 1986-05-29 | Nippon Sharyo Seizo Kaisha Ltd | Method for detecting corrosion of buried pipe or the like |
-
1987
- 1987-11-27 JP JP62297781A patent/JPH0814550B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01141346A (en) | 1989-06-02 |
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