この発明は、鉄筋コンクリート構造物の鉄筋の腐食量を予測する腐食進行予測方法と腐食進行予測装置とに関する。 The present invention relates to a corrosion progress prediction method and a corrosion progress prediction apparatus for predicting the corrosion amount of a reinforcing bar in a reinforced concrete structure.
従来から、鉄筋コンクリート構造物の鉄筋の腐食劣化進行予測方法が知られている（特許文献１参照）。 Conventionally, a method for predicting the progress of corrosion deterioration of reinforcing steel in a reinforced concrete structure is known (see Patent Document 1).
かかる鉄筋の腐食劣化進行予測方法は、鉄筋のかぶり位置での塩化物イオン濃度と、評価対象としての鉄筋コンクリートの建造地域の温度と、コンクリート品質の経時変化を考慮した塩化物イオンの見かけの拡散係数とに基づき、実際に建造されている評価対象としての鉄筋コンクリートの構造物の腐食速度を推定するものである。 The method for predicting the progress of corrosion deterioration of reinforcing bars is the chloride ion concentration at the cover position of the reinforcing bars, the temperature of the reinforced concrete as an evaluation target, and the apparent diffusion coefficient of chloride ions taking into account the changes in concrete quality over time. Based on the above, the corrosion rate of a reinforced concrete structure as an evaluation object actually built is estimated.
しかしながら、このような鉄筋コンクリート構造物の鉄筋の腐食劣化進行予測方法にあっては、鉄筋の腐食速度を推定するものであり、鉄筋の腐食がどのくらい進行しているかが分からないという問題があった。 However, in such a method for predicting the progress of corrosion deterioration of reinforcing bars in reinforced concrete structures, the corrosion rate of the reinforcing bars is estimated, and there is a problem that it is not known how much corrosion of the reinforcing bars has progressed.
この発明の目的は、鉄筋コンクリート構造物の鉄筋の腐食がどのくらい進行しているかが分かる鉄筋の腐食量を予測する腐食進行予測方法と腐食進行予測装置を提供することにある。 An object of the present invention is to provide a corrosion progress prediction method and a corrosion progress prediction apparatus for predicting a corrosion amount of a reinforcing bar, which can be understood how much corrosion of the reinforcing bar of a reinforced concrete structure is progressing.
請求項１の発明は、鉄筋コンクリート構造物の鉄筋の腐食量を予測する腐食進行予測方法であって、
測定時の温度における前記鉄筋の腐食速度を分極抵抗法によって測定し、この測定時の温度における腐食速度から年平均温度における腐食速度を求め、
採取した前記鉄筋コンクリート構造物のコンクリートコアから鉄筋のかぶり位置での塩化物イオン濃度を求め、
この塩化物イオン濃度から鉄筋のかぶり位置における塩化物イオン濃度の経時変化を拡散方程式によって求め、
前記鉄筋の年平均温度の腐食速度と前記塩化物イオン濃度の経時変化とに基づいて、年平均温度における測定時までの鉄筋の腐食速度および測定時以後の鉄筋の腐食速度の経時変化を求め、
前記測定時までの鉄筋の腐食速度および測定時以後の鉄筋の腐食速度の経時変化を基にして該鉄筋の腐食量の経時変化を求めて鉄筋の腐食量を予測することを特徴とする。The invention of claim 1 is a corrosion progress prediction method for predicting the corrosion amount of reinforcing steel in a reinforced concrete structure,
The corrosion rate of the rebar at the temperature at the time of measurement is measured by the polarization resistance method, and the corrosion rate at the annual average temperature is obtained from the corrosion rate at the temperature at the time of measurement,
Obtain the chloride ion concentration at the cover position of the reinforcing bar from the concrete core of the collected reinforced concrete structure,
From this chloride ion concentration, the change over time of the chloride ion concentration at the cover position of the reinforcing bar is obtained by the diffusion equation,
Based on the corrosion rate of the annual average temperature of the reinforcing bar and the temporal change of the chloride ion concentration, the corrosion rate of the reinforcing bar until the measurement at the annual average temperature and the temporal change of the corrosion rate of the reinforcing bar after the measurement are obtained,
Based on the corrosion rate of the reinforcing bar up to the time of the measurement and the change over time of the corrosion rate of the reinforcing bar after the time of measurement, the corrosion amount of the reinforcing bar is predicted by obtaining the change over time of the corrosion rate of the reinforcing bar.
請求項４の発明は、鉄筋コンクリート構造物の鉄筋の腐食量を予測する腐食進行予測装置であって、
測定時の温度における前記鉄筋の腐食速度を分極抵抗法によって測定する分極抵抗法測定部と、
この分極抵抗法測定部が測定した測定時の温度における腐食速度から年平均温度における腐食速度を求める年平均温度腐食速度演算部と、
採取した前記鉄筋コンクリート構造物のコンクリートコアから鉄筋のかぶり位置での塩化物イオン濃度を求める塩化イオン濃度分布分析部と、
この塩化イオン濃度分布分析部が求めた塩化物イオン濃度から鉄筋のかぶり位置における塩化物イオン濃度の経時変化を拡散方程式によって求める塩化物イオン濃度経時変化演算部と、
前記年平均温度腐食速度演算部が求めた年平均温度における腐食速度と、前記塩化物イオン濃度経時変化演算部が求めた塩化物イオン濃度の経時変化とに基づいて、年平均温度における測定時までの鉄筋の腐食速度および測定時以後の鉄筋の腐食速度の経時変化を求める腐食速度経時変化演算部と、
この腐食速度経時変化演算部が求めた腐食速度の経時変化から前記鉄筋の腐食量の経時変化を求める腐食量経時変化演算部とを備え、
この腐食量経時変化演算部が求めた鉄筋の腐食量の経時変化から鉄筋の腐食量を予測することを特徴とする。The invention of claim 4 is a corrosion progress prediction device for predicting the corrosion amount of reinforcing steel in a reinforced concrete structure,
A polarization resistance method measurement unit for measuring the corrosion rate of the reinforcing bar at a temperature at the time of measurement by a polarization resistance method;
An annual average temperature corrosion rate calculation unit for obtaining the corrosion rate at the annual average temperature from the corrosion rate at the measurement temperature measured by this polarization resistance method measurement unit,
A chloride ion concentration distribution analysis part for obtaining a chloride ion concentration at a cover position of the reinforcing bar from the concrete core of the collected reinforced concrete structure;
A chloride ion concentration temporal change calculation unit for obtaining a time-dependent change in chloride ion concentration at the cover position of the reinforcing bar from the chloride ion concentration obtained by the chloride ion concentration distribution analysis unit by a diffusion equation;
Based on the corrosion rate at the annual average temperature determined by the annual average temperature corrosion rate calculation unit and the temporal change in chloride ion concentration determined by the chloride ion concentration temporal change calculation unit, until the measurement at the annual average temperature. Corrosion rate temporal change calculation section for obtaining the corrosion rate of steel bars and the time course of corrosion rate of the reinforcing bars after measurement,
Corrosion rate aging change calculating unit for obtaining the aging change of the corrosion amount of the reinforcing bar from the aging change of the corrosion rate obtained by this corrosion rate aging change calculating unit,
It is characterized in that the corrosion amount of the reinforcing bar is predicted from the change with time of the corrosion amount of the reinforcing bar obtained by the corrosion amount temporal change calculation unit.
この発明によれば、鉄筋コンクリート構造物の鉄筋の腐食がどのくらい進行しているかが分かる。 According to the present invention, it can be seen how much corrosion of the reinforcing bars in the reinforced concrete structure has progressed.
以下、この発明に係る鉄筋コンクリート構造物の鉄筋の腐食量を予測する腐食進行予測方法を実施する腐食進行予測装置の実施の形態である実施例を図面に基づいて説明する。 Hereinafter, an embodiment which is an embodiment of a corrosion progress prediction apparatus for executing a corrosion progress prediction method for predicting a corrosion amount of a reinforcing bar of a reinforced concrete structure according to the present invention will be described with reference to the drawings.
図１に示す腐食進行予測装置１０は、分極抵抗法で鉄筋コンクリート構造物１の鉄筋２の腐食速度を測定する分極抵抗法測定装置（分極抵抗法測定部）２０と、鉄筋コンクリート構造物１から採取したコンクリートコア(図示せず)の深さ方向における塩化物イオン濃度分布を分析する塩化イオン濃度分布分析装置（塩化イオン濃度分布分析部）３０と、分極抵抗法測定装置２０が測定した腐食速度や塩化イオン濃度分布分析装置３０が分析した塩化物イオン濃度分布などから各種の演算を行う演算装置４０と、演算装置４０の演算結果などを表示する表示装置５０などとを備えている。
［分極抵抗法測定装置］
分極抵抗法測定装置２０は、電極２１を鉄筋コンクリート構造物１のコンクリート表面に当て、電極２２を露出させた鉄筋２に当てて分極抵抗法によって腐食速度を測定するものである。The corrosion progress prediction apparatus 10 shown in FIG. 1 is collected from a polarization resistance method measuring device (polarization resistance method measuring unit) 20 that measures the corrosion rate of the reinforcing bar 2 of the reinforced concrete structure 1 by the polarization resistance method, and the reinforced concrete structure 1. Corrosion rates and chlorides measured by the chloride ion concentration analyzer (chloride ion concentration analyzer) 30 and the polarization resistance measuring device 20 for analyzing the chloride ion concentration distribution in the depth direction of the concrete core (not shown). A calculation device 40 that performs various calculations from the chloride ion concentration distribution analyzed by the ion concentration distribution analyzer 30, a display device 50 that displays the calculation results of the calculation device 40, and the like are provided.
[Polarization resistance measurement device]
The polarization resistance measuring device 20 measures the corrosion rate by the polarization resistance method by placing the electrode 21 against the concrete surface of the reinforced concrete structure 1 and the electrode 22 against the exposed rebar 2.
分極抵抗法は、腐食速度を測定するために従来から一般的に用いられる方法の一つであって、自然電位から±約１０mＶ以内の微小な分極範囲から腐食速度を決定するものであり、自然電位から±約１０mＶ以内の電位と電流値を測定してグラフ化し、そのグラフの傾きから分極抵抗値を求め、この分極抵抗値を既存の公式に代入することにより腐食速度を求めるものである。分極抵抗法は、従来から知られているので詳細な説明は省略する。
［塩化イオン濃度分布分析装置］
塩化イオン濃度分布分析装置３０は、従来と同様にして塩化物イオン濃度分布を求めるものであり、その構成は従来と同様なのでその説明は省略する。
［演算装置］
演算装置４０は、年平均温度腐食速度演算部４１と、塩化物イオン濃度経時変化演算部４２と、腐食速度経時変化演算部４３と、腐食量経時変化演算部４４と、ひび割れ時期判断部４５などとを有している。
［年平均温度腐食速度演算部］
年平均温度腐食速度演算部４１は、分極抵抗法測定装置２０が求めた測定時の腐食速度Ｖmeasを測定対象である鉄筋コンクリート構造物の年平均温度Ｔmeanでの腐食速度（年平均温度腐食速度）Ｖmeanに換算する。この換算は下記のようにして求める。The polarization resistance method is one of the methods generally used to measure the corrosion rate, and determines the corrosion rate from a minute polarization range within ± 10 mV from the natural potential. A potential and current value within ± 10 mV from the potential are measured and graphed, a polarization resistance value is obtained from the slope of the graph, and the corrosion rate is obtained by substituting this polarization resistance value into an existing formula. Since the polarization resistance method is conventionally known, detailed description thereof is omitted.
[Chloride ion concentration analyzer]
The chloride ion concentration distribution analyzer 30 obtains a chloride ion concentration distribution in the same manner as in the prior art, and the configuration thereof is the same as that in the prior art, and the description thereof is omitted.
[Calculator]
The arithmetic unit 40 includes an annual average temperature corrosion rate calculation unit 41, a chloride ion concentration temporal change calculation unit 42, a corrosion rate temporal change calculation unit 43, a corrosion amount temporal change calculation unit 44, a crack timing determination unit 45, and the like. And have.
[Annual average temperature corrosion rate calculator]
The annual average temperature corrosion rate calculating unit 41 uses the corrosion rate Vmeas at the time of measurement obtained by the polarization resistance method measuring device 20 as the corrosion rate at the annual average temperature Tmean (annual average temperature corrosion rate) Vmean of the reinforced concrete structure to be measured. Convert to. This conversion is obtained as follows.
温度が鉄筋の腐食速度に及ぼす影響関数をｆ（Ｔ）とすると、測定時の腐食速度Ｖ（Ｔ）は下記の（１）式で求めることができる。 If the influence function of temperature on the corrosion rate of the reinforcing bar is f (T), the corrosion rate V (T) at the time of measurement can be obtained by the following equation (1).
Ｖ（Ｔ）＝α×ｆ（Ｔ） …（１）
温度Ｔと腐食速度Ｖとの関係を図２のグラフＧ１に示す。V (T) = α × f (T) (1)
The relationship between the temperature T and the corrosion rate V is shown in a graph G1 in FIG.
分極抵抗法測定装置２０によって求めた腐食速度がＶmeasとすると、Ｖ（Ｔ）＝Ｖmeasであり、測定時の温度をＴmeasとし、これらを（１）式に代入すると、
Ｖmeas＝α×f(Ｔmeas ) …（２）
となる。この（２）式からαが求まる。すなわち、α＝Ｖmeas／f(Ｔmeas )となる。Assuming that the corrosion rate obtained by the polarization resistance measuring device 20 is Vmeas, V (T) = Vmeas, the temperature at the time of measurement is Tmeas, and these are substituted into the equation (1),
Vmeas = α × f (Tmeas) (2)
It becomes. Α is obtained from the equation (2). That is, α = Vmeas / f (Tmeas).
したがって、αの値が求まると、鉄筋コンクリート構造物の年平均温度Ｔmeanでの腐食速度（年平均温度腐食速度）Ｖmeanは、
Ｖmean＝α×f(Ｔmean )＝（Ｖmeas／f(Ｔmeas )）×f(Ｔmean ) …（３）
となる。Therefore, when the value of α is obtained, the corrosion rate (annual average temperature corrosion rate) Vmean at the annual average temperature Tmean of the reinforced concrete structure is
Vmean = α × f (Tmean) = (Vmeas / f (Tmeas)) × f (Tmean) (3)
It becomes.
すなわち、年平均温度腐食速度演算部４１は、測定時の腐食速度Ｖmeasと温度Ｔmeas での影響関数の値f(Ｔmeas )からαを求め、このαと鉄筋コンクリート構造物１の年平均温度Ｔmeanでの影響関数の値f(Ｔmean)とから年平均温度Ｔmeanでの腐食速度Ｖmeanを求めるものである。なお、鉄筋コンクリート構造物１の年平均温度Ｔmeanは予めデータとして演算装置４０に入力しておく。 That is, the annual average temperature corrosion rate calculation unit 41 obtains α from the corrosion rate Vmeas at the time of measurement and the value f (Tmeas) of the influence function at the temperature Tmeas, and this α and the annual average temperature Tmean of the reinforced concrete structure 1 are obtained. The corrosion rate Vmean at the annual average temperature Tmean is obtained from the influence function value f (Tmean). In addition, the annual average temperature Tmean of the reinforced concrete structure 1 is previously input into the arithmetic unit 40 as data.
また、f(Ｔmeas )、f(Ｔmean )の関数式は、一般に知られており、例えば特許第４８７３４７２号公報や、ＪＣＯＳＳＡＲ２０１１論文集の「塩害劣化を受ける構造物の劣化モードを推定する確率論的手法の構築」に下記の（８）式として、
[数式３]
…（８）
と記載されているので、ここではその説明は省略する。
なお、Ｋは絶対温度、ＣT（Ｔ）はコンクリート温度による影響関数である。
［塩化物イオン濃度経時変化演算部］
塩化物イオン濃度経時変化演算部４２は、鉄筋のかぶり位置での塩化物イオン濃度の経時変化を下記のフィック（Ｆｉｃｋ）の拡散方程式を用いて計算する。Also, the function formulas of f (Tmeas) and f (Tmean) are generally known. The following formula (8)
[Formula 3]
(8)
The description is omitted here.
Here, K is an absolute temperature, and CT (T) is an influence function due to the concrete temperature.
[Chloride ion concentration change with time]
The chloride ion concentration change with time calculation unit 42 calculates the change with time in the chloride ion concentration at the cover position of the reinforcing bar using the following Fick diffusion equation.
なお、経過年数ｔとかぶり位置における塩化物イオン濃度との関係のグラフＧ２を図３に示す。
[数式１]
…（４）
ここで、Ｃ（ｘ,ｔ）は、かぶりの深さｘ（cm）、経過時間ｔ（秒）における塩化物イオン濃度（ｗｔ％）を表す。Ｃ′は初期混入時の塩化物イオン濃度（ｗｔ％）であり、Ｄcは塩化物イオンの見かけの拡散係数（cm２/sec）である。Ｗは表面に付着した飛来塩分のうちコンクリート内部へ浸透する量すなわち付着塩分量（ｗｔ％/cm２/sec）である。In addition, the graph G2 of the relationship between the elapsed time t and the chloride ion concentration in the fogging position is shown in FIG.
[Formula 1]
... (4)
Here, C (x, t) represents the chloride ion concentration (wt%) at the fog depth x (cm) and the elapsed time t (seconds). C ′ is a chloride ion concentration (wt%) at the time of initial mixing, and Dc is an apparent diffusion coefficient (cm 2 / sec) of chloride ions. W is an amount permeating into the concrete out of the flying salt adhering to the surface, that is, the amount of adhering salt (wt% / cm 2 / sec).
Ｄc,Ｗ及びＣ′は、これらの仮定した値を（４）式に代入して求めた計算結果と、採取したコンクリートコアの塩化物イオン濃度の分布データ（分析結果）とを比較し、その差の２乗の和の値を求めていき、それら仮定した値を変えていくごとに上記計算を繰り返し行い、その差の２乗の和が最も小さくなる時の値をＤc,Ｗ及びＣ′の値とするものである。すなわち、最小２乗法による近似計算によってＤc,Ｗ及びＣ′の値を求めるものである。
［腐食速度経時変化演算部］
腐食速度経時変化演算部４３は、塩化物イオン濃度経時変化演算部４２が求めた塩化物イオン濃度の経時変化から、測定時までの腐食速度と測定時以後の腐食速度を求める。すなわち、後述する（６）式により腐食速度の経時変化を演算する。Dc, W and C 'are calculated by substituting these assumed values into equation (4) and the distribution data (analysis results) of the chloride ion concentration of the sampled concrete core. The value of the sum of the squares of the differences is obtained, and the above calculation is repeated each time the assumed values are changed. The values when the sum of the squares of the differences is the smallest are obtained as Dc, W and C ′. The value of That is, the values of Dc, W and C ′ are obtained by approximate calculation by the least square method.
[Corrosion rate change with time]
The corrosion rate aging change calculation unit 43 obtains the corrosion rate until the measurement and the corrosion rate after the measurement from the change with time of the chloride ion concentration obtained by the chloride ion concentration aging change calculation unit 42. That is, the temporal change of the corrosion rate is calculated by the equation (6) described later.
ここで、塩化物イオン濃度が鉄筋の腐食速度に及ぼす影響関数をｆ（Ｃ）とすると、温度が一定の場合の塩化物イオン濃度に応じた腐食速度Ｖ（Ｃ）は以下の（５）式によって表現できる。 Here, if the influence function of the chloride ion concentration on the corrosion rate of the reinforcing bar is f (C), the corrosion rate V (C) corresponding to the chloride ion concentration when the temperature is constant is expressed by the following equation (5). Can be expressed by
Ｖ（Ｃ）＝β×ｆ（Ｃ） …（５）
かぶり位置での塩化物イオン濃度と、腐食速度Ｖとの関係を図４のグラフＧ３に示す。V (C) = β × f (C) (5)
The relationship between the chloride ion concentration at the fogging position and the corrosion rate V is shown in a graph G3 in FIG.
測定時のかぶり位置での塩化物イオン濃度Ｃmeasは塩化イオン濃度分布分析装置３０によって求められており、年平均温度での腐食速度Ｖmeanは年平均温度腐食速度演算部４１によって求められているので、測定時の塩化物イオン濃度Ｃmeasと腐食速度Ｖmeanとを（５）式に代入することによりβを求めることができる。 The chloride ion concentration Cmeas at the fogging position at the time of measurement is obtained by the chloride ion concentration distribution analyzer 30, and the corrosion rate Vmean at the annual average temperature is obtained by the annual average temperature corrosion rate calculation unit 41. Β can be obtained by substituting the chloride ion concentration Cmeas and the corrosion rate Vmean at the time of measurement into the equation (5).
すなわち、Ｖmean＝β×f(Ｃmeas)となり、β＝Ｖmean／f(Ｃmeas)となる。 That is, Vmean = β × f (Cmeas) and β = Vmean / f (Cmeas).
したがって、βの値が決まると、測定時までの腐食速度と測定時以降の腐食速度は、（４）,（５）式より、
Ｖ（Ｃ）＝（Ｖmean／f(Ｃmeas)）×ｆ（Ｃ）
＝（Ｖmean／f(Ｃmeas)）×f(Ｃ（ｘ,ｔ）) …（６）
となる。なお、f(Ｃmeas)の関数式は、一般に知られており、例えば特許第４８７３４７２号公報（または原子力発電所屋外重要土木構造物の耐震性能照査指針：平成１４年５月１７日発行、発行所：社団法人土木学会）や、ＪＣＯＳＳＡＲ２０１１論文集の「塩害劣化を受ける構造物の劣化モードを推定する確率論的手法の構築」に下記の（９）式として、
[数式３]
…（９）
と記載されているので、ここではその説明は省略する。Therefore, once the value of β is determined, the corrosion rate up to the time of measurement and the corrosion rate after the time of measurement are obtained from the equations (4) and (5):
V (C) = (Vmean / f (Cmeas)) × f (C)
= (Vmean / f (Cmeas)) * f (C (x, t)) (6)
It becomes. The function formula of f (Cmeas) is generally known. For example, Japanese Patent No. 4873472 (or guidelines for checking the seismic performance of nuclear power plant outdoor important civil structures: issued on May 17, 2002) : Construction of a probabilistic method for estimating the deterioration mode of structures subject to salt damage deterioration in the JCOSSAR 2011 paper collection
[Formula 3]
... (9)
The description is omitted here.
なお、Ｃc（Ｃ）はかぶり位置での塩化物イオン濃度による影響関数、Ｃ１crは腐食発生限界塩化物イオン濃度（ｋg/ｍ3）である。Cc (C) is an influence function depending on the chloride ion concentration at the fogging position, and C1cr is a corrosion occurrence limit chloride ion concentration (kg / m3 ).
図５は、経過年数ｔと年平均温度での腐食速度Ｖとの関係のグラフＧ４を示すものであり、グラフＧ４が年平均温度での腐食速度Ｖの経時変化を示す。
［腐食量経時変化演算部］
腐食量経時変化演算部４４は、（６）式を積分して鉄筋の腐食量の経時変化を求めていく。この鉄筋の腐食量の経時変化は図５のグラフＧ５に示す。
［ひび割れ時期判断部］
ひび割れ時期判断部４５は、腐食量経時変化演算部４４が積分して求めた腐食量とひび割れ発生限界腐食量Ｍcrとを比較してひび割れ発生時期ｔ２（図５参照）を求める。FIG. 5 shows a graph G4 of the relationship between the elapsed time t and the corrosion rate V at the annual average temperature, and the graph G4 shows the change with time of the corrosion rate V at the annual average temperature.
[Corrosion amount change with time]
The corrosion amount temporal change calculation unit 44 integrates the equation (6) to obtain the temporal change in the corrosion amount of the reinforcing bars. The change over time of the corrosion amount of the reinforcing bars is shown in a graph G5 in FIG.
[Crack time determination section]
The crack timing determination unit 45 determines the crack generation time t2 (see FIG. 5) by comparing the corrosion amount obtained by the integration of the corrosion amount temporal change calculation unit 44 with the crack generation limit corrosion amount Mcr.
ひび割れ発生限界腐食量Ｍcrは、例えば鉄筋径とかぶり深さとに応じて実験でひび割れ発生限界腐食量Ｍcrを予め求めておき、鉄筋径とかぶり深さとに対応させてひび割れ発生限界腐食量Ｍcrをメモリに記憶させておく。 For the cracking limit corrosion amount Mcr, for example, the crack generation limit corrosion amount Mcr is obtained in advance according to the rebar diameter and cover depth, and the crack generation limit corrosion amount Mcr is stored in correspondence with the rebar diameter and cover depth. Remember me.
鉄筋コンクリート構造物の鉄筋径やかぶり深さは分かっているので、測定前に鉄筋径とかぶり深さを予め入力しておく。
［表示装置］
表示装置５０は、腐食速度経時変化演算部４３が演算した腐食速度の経時変化を示すグラフＧ４（図５参照）と、腐食量経時変化演算部４４が演算した腐食量の経時変化を示すグラフＧ５と、ひび割れ時期判断部４５が判断したひび割れ発生時期ｔ２と、ひび割れ発生限界腐食量Ｍcrなどとを表示部５１（図５参照）に表示する。
［測定方法］
次に、腐食進行予測装置１０によって鉄筋コンクリート構造物の鉄筋の腐食量の経時変化を測定する測定方法について説明する。Since the rebar diameter and the cover depth of the reinforced concrete structure are known, the rebar diameter and the cover depth are input in advance before the measurement.
[Display device]
The display device 50 includes a graph G4 (see FIG. 5) showing the corrosion rate aging calculated by the corrosion rate aging change calculating unit 43 and a graph G5 showing the aging change of the corrosion amount calculated by the corrosion amount aging calculating unit 44. The crack generation time t2 determined by the crack time determination unit 45, the crack generation limit corrosion amount Mcr, and the like are displayed on the display unit 51 (see FIG. 5).
[Measuring method]
Next, a measurement method for measuring the change over time in the corrosion amount of the reinforcing bars of the reinforced concrete structure by the corrosion progress prediction device 10 will be described.
先ず、分極抵抗法測定装置２０によって、図１に示すように電極２１を鉄筋コンクリート構造物１のコンクリート表面に当て、電極２２を露出させた鉄筋２に当てて分極抵抗法により鉄筋コンクリート構造物１の鉄筋２の腐食速度Ｖmeasを求める。 First, as shown in FIG. 1, the electrode 21 is applied to the concrete surface of the reinforced concrete structure 1 by the polarization resistance measurement device 20, and the electrode 22 is applied to the exposed rebar 2, and the rebar of the reinforced concrete structure 1 by the polarization resistance method. 2 is determined.
一方、鉄筋コンクリート構造物１からコンクリートコア(図示せず)を採取し、この採取したコンクリートコアの深さ方向の塩化物イオン濃度の濃度分布を塩化イオン濃度分布分析装置３０によって求める。 On the other hand, a concrete core (not shown) is sampled from the reinforced concrete structure 1, and the chloride ion concentration distribution analyzer 30 determines the concentration distribution of the chloride ion concentration in the depth direction of the collected concrete core.
演算装置４０の年平均温度腐食速度演算部４１は、分極抵抗法測定装置２０が求めた測定時の腐食速度測定値Ｖmeasを、上記の（１）式〜（３）式に基づいて鉄筋コンクリート構造物の年平均温度Ｔmeanの腐食速度Ｖmeanに変換する。 The annual average temperature corrosion rate calculation unit 41 of the calculation device 40 calculates the corrosion rate measurement value Vmeas at the time of measurement obtained by the polarization resistance method measurement device 20 based on the above equations (1) to (3). Is converted into a corrosion rate Vmean at an annual average temperature Tmean.
他方、塩化物イオン濃度経時変化演算部４２は、塩化イオン濃度分布分析装置３０が分析した塩化物イオン濃度の濃度分布に基づいて、鉄筋のかぶり位置での塩化物イオン濃度の経時変化を例えば（４）式の拡散方程式の解から求める
める。On the other hand, the chloride ion concentration temporal change calculating unit 42 calculates, for example, the temporal change of the chloride ion concentration at the rebar cover position based on the chloride ion concentration distribution analyzed by the chloride ion concentration distribution analyzer 30 ( 4) Obtain from the solution of the diffusion equation.
腐食速度経時変化演算部４３は、塩化物イオン濃度経時変化演算部４２が求めた塩化物イオン濃度の経時変化から、測定時までの腐食速度と測定時以後の腐食速度の経時変化を（６）式により演算して求める。 The corrosion rate change with time calculation unit 43 calculates the change in corrosion rate up to the time of measurement and the change over time of the corrosion rate after the measurement from the change over time in the chloride ion concentration obtained by the chloride ion concentration change over time calculation unit (6). Calculated using an equation.
腐食量経時変化演算部４４は、腐食速度経時変化演算部４３が求めた腐食速度の経時変化に基づいて、鉄筋２の腐食量の経時変化を求めていく。すなわち、（６）式を積分して鉄筋２の腐食量の経時変化を求めていく。 The corrosion amount change with time calculation unit 44 obtains the change with time of the corrosion amount of the reinforcing bar 2 based on the change with time of the corrosion rate obtained by the corrosion rate change with time calculation unit 43. That is, the change with time of the corrosion amount of the reinforcing bar 2 is obtained by integrating the expression (6).
ひび割れ時期判断部４５は、鉄筋２の腐食量の経時変化と、ひび割れ発生限界腐食量Ｍcrとを比較してひび割れ発生時期ｔ２を求める。 The crack timing determination unit 45 compares the time-dependent change in the corrosion amount of the reinforcing bar 2 with the crack generation limit corrosion amount Mcr to obtain the crack generation timing t2.
表示装置５０は、腐食速度経時変化演算部４３が演算して求めた腐食速度Ｖの経時変化を示すグラフＧ４と、腐食量経時変化演算部４４が演算して求めた腐食量の経時変化を示すグラフＧ５とを図５に示すように表示部５１に表示する。 The display device 50 shows a graph G4 showing the change over time of the corrosion rate V calculated by the corrosion rate temporal change calculation unit 43 and the change over time of the corrosion amount calculated by the corrosion amount temporal change calculation unit 44. The graph G5 is displayed on the display unit 51 as shown in FIG.
また、表示装置５０は、図５に示すように、進展期の残存期間ｔａやひび割れ発生時期ｔ２や潜伏期ｔｂや進展期ｔｃなども表示部５１に表示する。この場合、鉄筋コンクリート構造物１の完成時期などのデータを入力しておく。 Further, as shown in FIG. 5, the display device 50 also displays the remaining period ta, the crack generation time t2, the latent period tb, the progress period tc, and the like in the progress period on the display unit 51. In this case, data such as the completion time of the reinforced concrete structure 1 is input.
このように、分極抵抗法測定装置２０によって鉄筋コンクリート構造物１の鉄筋２の腐食速度Ｖmeasを求め、塩化物イオン濃度分布分析装置３０によってコンクリートコアの深さ方向の塩化物イオン濃度の濃度分布を求めれば、演算装置４０が腐食速度Ｖや腐食量の経時変化を演算して求め、この求めた腐食速度Ｖの経時変化と腐食量の経時変化とのグラフＧ４,Ｇ５が表示装置５０の表示部５１に表示されるので、鉄筋の腐食がどのくらい進行しているのか、また、これから鉄筋の腐食がどのくらい進行していくのかが分かることになる。 Thus, the corrosion resistance Vmeas of the reinforcing bar 2 of the reinforced concrete structure 1 can be obtained by the polarization resistance method measuring device 20, and the concentration distribution of the chloride ion concentration in the depth direction of the concrete core can be obtained by the chloride ion concentration distribution analyzing device 30. For example, the calculation device 40 calculates the corrosion rate V and the change over time of the corrosion amount, and graphs G4 and G5 of the obtained change over time of the corrosion rate V and the change over time of the corrosion amount are displayed on the display unit 51 of the display device 50. Will show how much corrosion of the reinforcing bar has progressed and how much corrosion of the reinforcing bar will progress from now on.
さらに、ひび割れ発生時期ｔ２も表示部５１に表示されるので、鉄筋コンクリート構造物１の耐用年数が明確なものとなる。 Furthermore, since the crack generation time t2 is also displayed on the display unit 51, the useful life of the reinforced concrete structure 1 becomes clear.
ところで、図１に示す腐食進行予測装置１０の分極抵抗法測定装置２０で鉄筋の腐食速度Ｖmeasを測定する場合、分極抵抗法測定装置２０のみを現場に持っていって腐食速度Ｖmeasを測定する。この測定は、分極抵抗法測定装置２０の一方の電極(図示せず)をコンクリート表面に当てるとともに、鉄筋を露出させて該鉄筋に他方の電極(図示せず)を接続して行う。 By the way, when measuring the corrosion rate Vmeas of the reinforcing bar with the polarization resistance method measuring device 20 of the corrosion progress prediction device 10 shown in FIG. 1, only the polarization resistance method measuring device 20 is brought to the site and the corrosion rate Vmeas is measured. This measurement is performed by placing one electrode (not shown) of the polarization resistance measurement device 20 on the concrete surface, exposing the reinforcing bar, and connecting the other electrode (not shown) to the reinforcing bar.
測定が終了したら、分極抵抗法測定装置２０を持ち帰って腐食進行予測装置１０の演算装置４０に接続し、分極抵抗法測定装置２０の測定データを演算装置４０に入力させる。 When the measurement is completed, the polarization resistance measurement device 20 is brought back and connected to the calculation device 40 of the corrosion progress prediction device 10, and the measurement data of the polarization resistance measurement device 20 is input to the calculation device 40.
この場合、現場では鉄筋コンクリート構造物からコンクリートコアを採取し、このコンクリートコアを持ち帰って塩化イオン濃度分布分析装置３０によって塩化物イオン濃度の濃度分布を分析させる。 In this case, a concrete core is collected from the reinforced concrete structure at the site, and the concrete core is brought back and analyzed for the chloride ion concentration distribution by the chloride ion concentration distribution analyzer 30.
また、予めコンクリートコアを採取して塩化イオン濃度分布分析装置３０によって塩化物イオン濃度の濃度分布を分析させておき、この分析したデータを予め演算装置４０に入力させておく。そして、塩化イオン濃度分布分析装置３０を演算装置４０から外し、分極抵抗法測定装置２０と演算装置４０と表示装置５０とを現場に持って行き、分極抵抗法測定装置２０によって腐食速度Ｖmeasを測定すれば、その現場で鉄筋の腐食量の経時変化やひび割れ発生時期ｔ２や腐食速度Ｖの経時変化などが求められることになる。 Further, a concrete core is collected in advance, the chloride ion concentration distribution analyzer 30 analyzes the chloride ion concentration distribution, and the analyzed data is input to the arithmetic unit 40 in advance. Then, the chloride ion concentration distribution analyzer 30 is removed from the arithmetic device 40, the polarization resistance method measuring device 20, the arithmetic device 40 and the display device 50 are brought to the site, and the polarization resistance method measuring device 20 measures the corrosion rate Vmeas. In this case, the time-dependent change in the corrosion amount of the reinforcing bars, the time t2 when cracks occur, and the time-dependent change in the corrosion rate V are required.
上記実施例では、拡散方程式の解として（４）式を用いているが、他の拡散方程式の解を用いてもよい。例えば、下記の（７）式の解を用いてもよい。
[数式２]
…（７）
ただし、Ｄは塩化物イオンの見掛けの拡散係数、Ｃ0はコンクリート表面における塩化物イオン濃度、Ｃ’は初期混入塩化物イオン濃度、Ｘはコンクリート表面からの距離、ｔは供用期間（経過時間）である。In the above embodiment, the equation (4) is used as a solution of the diffusion equation, but a solution of another diffusion equation may be used. For example, the following equation (7) may be used.
[Formula 2]
... (7)
Where D is the apparent diffusion coefficient of chloride ions, C0 is the chloride ion concentration on the concrete surface, C ′ is the initial mixed chloride ion concentration, X is the distance from the concrete surface, t is the service period (elapsed time) It is.
この発明は、上記実施例に限られるものではなく、特許請求の範囲の各請求項に係る発明の要旨を逸脱しない限り、設計の変更や追加等は許容される。 The present invention is not limited to the above-described embodiments, and design changes and additions are permitted without departing from the spirit of the invention according to each claim of the claims.
１ 鉄筋コンクリート構造物
２ 鉄筋
２０ 分極抵抗法測定装置（分極抵抗法測定部）
３０ 塩化イオン濃度分布分析装置（塩化イオン濃度分布分析部）
４１ 年平均温度腐食速度演算部
４２ 塩化物イオン濃度経時変化演算部
４３ 腐食速度経時変化演算部
４４ 腐食量経時変化演算部1 Reinforced concrete structure 2 Reinforcement 20 Polarization resistance method measuring device (polarization resistance method measuring unit)
30 Chloride concentration distribution analyzer (Chloride concentration distribution analyzer)
41 Year Average Temperature Corrosion Rate Calculator 42 Chloride Ion Concentration Time Change Calculator 43 Corrosion Rate Time Change Calculator 44 Corrosion Amount Time Change Calculator
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| JP2012113801AJP2013242163A (en) | 2012-05-17 | 2012-05-17 | Corrosion progress prediction method and corrosion progress prediction apparatus |
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| JP2012113801AJP2013242163A (en) | 2012-05-17 | 2012-05-17 | Corrosion progress prediction method and corrosion progress prediction apparatus |
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| JP2013242163Atrue JP2013242163A (en) | 2013-12-05 |
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| JP2012113801APendingJP2013242163A (en) | 2012-05-17 | 2012-05-17 | Corrosion progress prediction method and corrosion progress prediction apparatus |
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