JP3096240B2 - Diagnosis method and apparatus for corrosion probability or degree of corrosion of reinforcing steel in concrete structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for diagnosing the probability or degree of corrosion of reinforcing steel in various concrete structures such as buildings, bridges and tunnels.

[0002]

2. Description of the Related Art In general, a reinforcing steel is buried in a concrete structure from the viewpoint of securing the strength. However, if the corrosion of the buried reinforcing steel progresses, the strength of the structure is reduced. Yes. However, since the rebar is buried in the structure, it is not possible to diagnose whether the rebar is corroded from the concrete surface.

Therefore, conventionally, ASTM (American Society for Foam) has been used as a method for diagnosing corrosion of reinforcing steel.
A method of measuring the degree of corrosion of reinforcing steel by a method of measuring the natural potential of uncoated reinforcing steel in concrete using C876-87 of r Testing and Materials) has been widely used. This is because in a healthy concrete structure, the reinforcing steel is passivated due to strong alkalinity, and its natural potential is about -100 mV to -200 mV.
(CSE), but chloride penetration and neutralization (carbonation)
Focusing on the fact that the reinforcing bar becomes active and corrosion progresses, and the corrosion progresses, the potential changes in the negative direction (increases in the negative direction) as the corrosion progresses. Is a method of diagnosing the probability of In this apparatus, the probability of corrosion is diagnosed using the method shown in Table 1.

[0004]

However, in this method of diagnosing the probability of corrosion,
There is a problem that the uncertainty area is large and that the actual diagnosis results also vary and lack reliability.

[0006]

Accordingly, a conventional durability diagnosis series 3 for concrete, "Diagnosis of steel bar corrosion" (19)
As described on page 86 of May 28, 1993, Morikita Shuppan Co., Ltd.), the spontaneous potential of a reinforcing bar is measured via a cover on a concrete surface, and thus the true potential of a corrosion portion of a reinforcing bar is not necessarily required. Does not indicate
In addition, various factors affect the measured value, which causes the potential to fluctuate. In addition, the OTH84205 report shows the main factors that are thought to affect measured values and the degree of those effects. Of these factors, those that have the greatest effect are electrochemical and resistive. It has been. The former is due to the non-uniformity of the chemical and physical properties of concrete, and the latter is due to the resistance of the concrete itself and the carbonation layer on the surface, which are dependent on the water content and salt content. Since the potential fluctuates in various ways depending on the properties of the fogged portion, the determination based on the measurement of the spontaneous potential does not match the actual corrosion state, and therefore lacks reliability.

On the other hand, "Rust prevention management" Vol. 3
9, As described on pages 393 to 399 of the November 1995 issue (issued by the Japan Rust Prevention Technology Association on November 1, 1995), there is no effect of various influences on the vicinity of reinforcing bars. When the natural potential (internal potential) was measured,
Reliable results were obtained. However, it is practically impossible to measure the internal potential at all places where it is desired to measure, and in this case, the difference between the natural potential (surface potential) actually measured on the concrete surface and the internal potential is used as a correction potential, and this is used. The method of correcting the spontaneous potential measured on the concrete surface was adopted. However, in the case of this diagnostic method, in order to calculate the correction potential, it is necessary to measure the internal potential, but the correction potential is effective only for a part under the same environment in one concrete structure, For example, when the properties such as the moisture content of the fogged portion are different due to different conditions such as the degree of dryness between the south-facing surface and the north-facing surface, a correct correction potential is obtained unless the internal potential is measured separately. You will not be able to do it. As a result, a large number of holes for measuring the internal potential must be formed in one concrete structure, which is cumbersome and cumbersome, resulting in poor workability. The measurement must be performed in a state different from the condition at the time of measuring the surface potential performed in a sufficiently wet state, in which the hole site must not be wet, and the hole must be closed after the measurement. Thus, if it is possible to determine the extent of corrosion, not just the presence or absence of corrosion of the reinforcing bars, it will be important information in the case of repair, etc. The policy for the investigation, diagnosis and repair of salt-damaged buildings indicated in the report of "Development of Durability Factory Technology for Concrete" made by the Ministry of Construction Comprehensive Technology Development Project (Ministry of Construction, November 1988) At present, it is performed visually based on the classification of the reinforcing steel corrosion degree (shown in Table 2). For this reason, if it is possible to diagnose the probability of corrosion or the degree of corrosion of the reinforcing bar from the measurement results of the natural potential, it is desirable to improve the efficiency and accuracy of the reinforcing bar corrosion diagnosis, but at present there is no such knowledge, These have problems to be solved by the present invention.

[0008]

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve these problems in view of the above-mentioned circumstances, and is intended to reduce the probability of corrosion or the degree of corrosion of reinforcing steel in a concrete structure. Upon diagnosis by measuring the natural potential, with respect to the actually measured natural potential, the correction by the water content of the concrete head portion of the concrete structure, co
Correction for concrete salt presence, concrete charcoal
This is a method for diagnosing the probability of corrosion or the degree of corrosion of a reinforcing bar in a concrete structure, which is to be diagnosed by further correcting the oxidation depth . In this case, the correction based on the moisture content can be performed in a low range in which the moisture content of the cover portion in the concrete structure affects the measured value of the self potential. In this case, the range to be corrected by the moisture content can be such that the moisture content of the concrete at the cover portion of the concrete structure is about 6% or less , and this was confirmed by an experiment. In the above, in the case where the correction based on the presence or absence of salt is further added to the correction based on the water content, if X is the water content of the concrete in the cover portion of the concrete structure, if the concrete does not include the salt, the correction formula based on the water content = −25X + 180, and when the salt content is 3 kg / m ^3, it is approximately calculated as a correction formula based on the water content = −20X + 150. When the concrete has a salt content other than the above, the correction formula calculated from the above two formulas is used. It can be assumed to be calculated by an equation. The formula in this case can be a second-order or higher-dimensional formula, but in view of the fact that the measurement error of the natural potential is about ± 20 mV, it can be obtained by a simple linear proportional formula. Is good. By the way, the values of the constants of the above two correction formulas are approximated as average values from experiments described later, and it is considered that there is a fluctuation due to data accumulation due to accumulation of future experiments. It is estimated that there is no large change such as doubling or halving, and it can be suppressed to a small one. Furthermore, when the correction based on the water content is further corrected by the carbonation depth, if Y is the carbonation depth, if the concrete does not contain salt, the correction formula by carbonation depth = 8Y and the salt is 3 kg. / M ³ is calculated approximately as a correction formula based on the depth of carbonation = 4Y, and when the concrete has a salt content other than the above, the correction formula is calculated using the correction formula calculated from the above two formulas. It can be assumed that The formula in this case can be a higher-order formula of second order or higher, as described above, but the difference after measuring the self potential is ± 20 mV.
In view of the fact that there is a degree, it can be said that a simple linear proportional expression is sufficient. The constant value in this case is also assumed to be the same as described above. Also, in diagnosing the corrosion probability or degree of corrosion of the reinforcing steel in concrete structures by measuring the natural potential, it is necessary to correct the measured natural potential in consideration of the water content, carbonation depth, and salt content of concrete. The correction amount Z is as follows: when W is the moisture content, A is the moisture content count, t is the carbonation depth, and B is the carbonation depth count, the correction amount Z = C−A × W + B × t A = 25−5 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ) B = 8−4 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ) C = 180-30 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ), and the corrected natural potential obtained by correcting the measured self potential by this correction amount Z Iron in concrete structures for evaluating the probability of corrosion or degree of corrosion of reinforcing bars by electric potential A corrosion probability or extent of corrosion diagnostic method. In this case, the evaluation of the degree of corrosion of the reinforcing steel by the corrected natural potential is performed by correcting the corrected natural potential E (mV) Corrosion degree Corrosion state of the reinforcing steel −250 <E I Black scale without corrosion −350 <E ≦ −250 II Slight spot rust on the surface -450 <E ≦ -350 III Thin floating rust on the concrete with rust attached E ≦ -450 IV, V Expansive rust on the concrete However, remarkable expansive rust is generated from a relatively small number of cross-sectional defects, and it can be evaluated in a state where there is a cross-sectional defect.

[0010] Corrosion of reinforcing steel in concrete structures
Probability or degree of corrosion, self potential measurement on concrete surface
In performing the diagnosis and displaying the results, the probability of corrosion or the degree of corrosion of the reinforcing steel in the concrete structure was calculated by taking into account the water content of the concrete, the depth of carbonation, and the amount of salt in the measured natural potential. And the correction amount Z
Is W for water content, A for water content count, t for carbonation depth,
When B is a carbonation depth count, the correction amount Z = C−A × W + B × t A = 25−5 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ) B = 8−4 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ) C = 180−30 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ) Approximately calculated, the measured natural potential is used as a corrected natural potential obtained by correcting the corrected natural potential with the correction amount Z, and the evaluation of the corrosion degree based on the corrected natural potential is performed using the corrected natural potential E (mV). Situation -250 <E I Corrosion-free black scale -350 <E ≦ -250 II Slight spot rust on surface -450 <E ≦ -350 III Thin floating rust on concrete Rust is attached E ≦ −450 IV, V Expansive rust is generated, The cross-section defect is a diagnostic device for the probability of corrosion or the degree of corrosion of reinforcing steel in concrete structures, which is evaluated by remarkably expanding rust from a relatively small state, and is evaluated by classifying it into the state with a cross-section defect. In this way, a favorable corrosion probability or corrosion rate can be evaluated even for an uncertain region that could not be evaluated until now. In this case, in the display of the result, the position of the reinforcing bar is displayed, and the display of the position of the reinforcing bar is identified and displayed by a plurality of sections preliminarily classified based on the corrosion probability or the degree of corrosion. Things. Further, in this method, when identifying and displaying the reinforcing bar position based on the corrosion probability or the degree of corrosion, when adjacent measurement points are in the same category of corrosion probability or degree of corrosion, the same classification is applied between the fixed positions on both sides. An identification display may be provided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The high reliability of the diagnosis of the corrosion probability or the degree of corrosion by the measurement of the internal potential described above means that the measured natural potential is not affected by the degree of drying or carbonation of concrete. Therefore, the inventors of the present invention examined using a test specimen how the water content and the carbonation depth of the concrete affected the natural potential. In addition, the influence on the presence or absence of salt (mainly NaCl) was also examined.・ Specimen form: Concrete unit cement amount is 30
0 kg / m ³ water cement ratio is 65% ・ Method of measuring moisture content of test specimen: The moisture content of the surface layer of the reinforcing bar can be measured normally using a nondestructive simple moisture meter. -Measuring method of carbonation depth (neutralization depth) of test specimen: by phenolphthalein method. In other words, concrete is actually suspended, and the depth of a portion not colored by the phenolphthalein solution is measured. Measurement method of self potential: according to the method described in ASTM C876-87. Here, it is advisable to avoid using an acidic solution or a chloride ion-containing internal solution as the reference electrode, and it is preferable to use a rotary lead reference electrode for quick measurement. The potentiometer preferably has an input impedance of 100 MΩ or more.

<Study on change in water content and change in spontaneous potential when no salt is added> The internal potential (E) of the test piece obtained by changing the water content of the fogging surface layer from about 8% to 3%. ₁ ) and the surface potential (E ₂ ) were measured and plotted in FIG.

According to this, the internal potential (E ₁ ) is almost unaffected by the change in the water content and is constant, whereas the surface potential (E ₂ ) changes almost linearly with the change in the water content. Was observed. Then, it was found that the correction of “E ₂ −E ₁ ” can correct the spontaneous potential by the water content, and the calculated correction formula was as follows. In the formula, X is the moisture content (%) of the surface layer portion of the concrete cover. Correction formula based on water content = -25X + 180

<Study on fluctuation of spontaneous potential accompanying the progress of carbonation in the absence of salt addition> A specimen having a carbonation depth of 0 to about 8 millimeters was prepared for each of the specimens, and the same procedure was applied to these specimens. The potential (E ₁ ) and the surface potential (E ₂ ) were measured and plotted in FIG. In addition, the internal potential (E ₁ ) was measured for a site that was not carbonated.

According to this, the internal potential (E ₁ ) is almost unaffected by the carbonation depth and is constant, while the surface potential (E ₂ ) changes almost linearly with the change in the carbonation depth. Was observed. Then, it was found that the correction of “E ₂ −E ₁ ” can correct the spontaneous potential by the carbonation depth, and the calculated correction formula was as follows. In the formula, Y is the carbonation depth (mm) of the cover portion of the concrete. Correction formula based on carbonation depth = 8Y

Further, in examining the carbonation depth, the effect of the water content was examined. That is, of the specimen was immersed in 1 week water for those carbonation depth 6 mm and 7.5 mm and when it tries to measure the surface potential in the same manner as _{(E 2), E 2 ≒} E _{Was one} . When the moisture content of the fogging surface layer portion was measured at this time, it was about 5.5 to 6%. From this, the correction for the carbonation depth can be ignored if the water content exceeds approximately 5.5-6%.
It has been found that the correction is necessary only for the ones of 5 to 6% or less. Here, regarding the boundary of whether or not to correct the spontaneous potential based on the water content, the water content is set to 5.5 to 6%.
There is a problem in which value is set specifically between the two. For example, when the corrosion rate is evaluated based on the assumption that the correction is not performed on the basis of 5.5%, or when the corrosion degree is evaluated based on the assumption that the correction is not performed based on the 6%, Many experiments have revealed that there is no great difference between the evaluations.

<Study on change in water content and change in spontaneous potential when salt is added> A specimen containing 3 kg / m ³ of sodium chloride as a salt was prepared, and the water content of this sample was about 9% to 3%. About what changed to
Similarly, the internal potential (E ₁ ) and the surface potential (E ₂ ) were measured, and the results are shown in FIG. According to this, it was observed that those containing salts were also linearly affected by the change in the water content with respect to the internal potential (E ₁ ). Based on the result, the correction formula calculated for the case including the salt was as follows. In the formula, X is the moisture content (%) of the surface layer portion of the concrete cover. Correction formula based on water content = −20 × + 150

<Study on fluctuation of spontaneous potential accompanying the progress of carbonation when salt is added> Similarly, for a specimen containing salt, one having a carbonation depth of 0 to about 11 mm was prepared. When the internal potential (E ₁ ) and the surface potential (E ₂ ) were measured in the same manner, the results were as shown in FIG. According to this, the internal potential (E ₁ ) is constant without being largely influenced by the carbonation depth, while
It was observed that the surface potential (E ₂ ) changed almost linearly with the change in the depth of carbonation, and the correction formula calculated based on this based on that containing salt was as follows. Where Y
Is the carbonation depth (mm) of the concrete cover. Correction formula based on carbonation depth = 4Y

When these correction formulas are put together into one formula, the correction amount Z is such that W is the moisture content, A is the moisture content count, t is the carbonation depth, and B is the carbonation depth count. Where, the correction amount Z = C−A × W + B × t A = 25−5 / 3 × (measurement result of the salt content of the uncarbonated portion: kg / m ³ ) B = 8−4 / 3 × ( Measurement result of salt content of uncarbonated part:
kg / m ³ ) C = 180-30 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ).

<Study on whether or not the correction formula is effective> Next, the natural potential, salinity, water content, and carbonation depth of various concrete structures were measured, and then the reinforcing bars of the measured portions were chipped. Then, the degree of corrosion of the reinforcing steel was visually observed, and evaluated based on Table 2 above. Table 3 shows some of the results. Table 3 shows the AST
The evaluation of the degree of corrosion by the self potential measured by M is described for reference.

[0021]

[Table 3]

From these results, the calculated corrected self-potential and the corrosion rates I to V are evaluated according to the relationship shown in Table 4, whereby a more accurate evaluation of the corrosion probability or corrosion rate of the reinforcing steel is performed. Can be.

Next, a diagnostic device for displaying these corrected natural potentials E on the display 1 for diagnosis is provided by an input means (keyboard) 2 for inputting data and a keyboard 2. And a control unit 3 for performing a necessary calculation based on the input signal of the above and outputting the calculation result to the display 1. If necessary, the control unit 3 outputs the calculation result to a printing means (printer) and displays it as a printed matter. Of course, it is good. Now, the control unit 3 is a microcomputer (C
PU), necessary electronic parts such as memory, electrical parts and equipment, etc., but a display means for displaying the corrosion probability or degree of corrosion of the reinforcing bar in a state of displaying the position of the vertical and horizontal reinforcing bars in the concrete structure. Included as a program.

First, in this case, the relationship between the actual reinforcing bar position of the concrete structure to be diagnosed and the display display is required. For this purpose, it is necessary to recognize the reinforcing bar position of the concrete structure. The rebar position data can be roughly analogized with a design drawing (construction drawing) or the like, but there are many cases where the design drawing and actual construction are different. Therefore, the measurement range is determined by a square frame at the site, and the position of the rebar on this frame line is searched. As this search means, it is effective to use a commonly used reinforcing bar detector (metal detector). Then, by connecting the searched reinforcing bar positions vertically and horizontally, it is possible to estimate the intersection of the vertical and horizontal reinforcing bars, and it is preferable to measure the self-potential difference, the salt concentration, the water content, and the carbonation depth at each of these intersections, as shown in FIG. The screen shows an example of measuring each intersection of the reinforcing bars. In this way, the actual rebar position is searched for, the measurement position is specified, and each measurement is performed. However, the number of measurement points is limited to about 400 (that is, the number of vertical and horizontal rebars is 20 each). As a guide, it is needless to say that the present invention is not limited to this. Then, the control unit 3 calculates the correction amount Z by the above-described approximate expression based on the measurement result at each measurement position, and calculates the corrected natural potential. Based on the evaluation table classified as shown in Table 4 for the calculated corrected self potential at each correction position, the corrosion probability or the degree of corrosion is evaluated, and the corresponding corrosion probability or corrosion degree is classified and displayed (for example, display). Are displayed by color if they can be displayed in color, and are displayed by differences in shading or shading in monochrome display). In this case,
If adjacent measurement points are evaluated as having the same degree of corrosion probability or degree of corrosion, a similar identification is made between them to indicate that they are in the same category of corrosion probability or degree of corrosion, and the corresponding identification mark is displayed. Have been. Therefore, by looking at the display, it is easy to simply evaluate the corrosion probability or the degree of corrosion of the reinforcing bar at which position, and the repair corresponding to the degree of corrosion can be performed. .

[Brief description of the drawings]

FIG. 1 shows the water content and internal potential (E
FIG. 1 is a graph plotting the relationship between the measurement results of ₁ ) and the surface potential (E ₂ ).

FIG. 2 is a graph plotting the relationship between the carbonation depth and the measurement results of internal potential (E ₁ ) and surface potential (E ₂ ) when no salt is added.

FIG. 3 is a graph plotting the relationship between the measurement results of the water content, internal potential (E ₁ ), and surface potential (E ₂ ) when a salt is added.

FIG. 4 is a graph plotting the relationship between the measurement results of the carbonation depth, internal potential (E ₁ ), and surface potential (E ₂ ) when a salt is added.

FIG. 5 is a schematic diagram of an apparatus for diagnosing the probability of corrosion or the degree of corrosion of a reinforcing bar in a concrete structure.

FIG. 6 is a schematic front view of a display screen.

──────────────────────────────────────────────────続 き Continuing from the front page (56) References Tamura "Rust Prevention Control" Vol.33, No.8, 1989, pp.247-250 Obayashi Technical Report, No.29, 1984 105-155 Obayashi Technical Report, No.36 1988 129-133 Cement / Concrete, No.551 1993 pp.72-79 (58) Fields investigated (Int.Cl. ⁷ , DB name) File (JOIS)

Claims (10)

(57) [Claims] In diagnosing a corrosion probability or a corrosion degree of a reinforcing bar in a concrete structure by measuring a natural potential,
To correct the measured natural potential based on the concrete moisture content at the cover of the concrete structure ,
Correction by the presence or absence of salt in the salt, carbonation depth of concrete
A method of diagnosing the probability of corrosion or the degree of corrosion of a reinforcing steel in a concrete structure, which is to be further diagnosed with correction according to height. 2. The method according to claim 1, wherein the correction based on the moisture content is performed in a low range in which the moisture content of the cover portion in the concrete structure affects the measured value of the self potential. Diagnosis method of corrosion probability or corrosion degree. 3. The method according to claim 2, wherein the correction based on the water content is a range of the corrosion probability or the degree of corrosion of the reinforcing steel in the concrete structure in which the water content of the concrete in the cover portion of the concrete structure is about 6% or less . Diagnostic method. 4. The method according to claim 1, wherein when the correction based on the water content is further corrected based on the presence or absence of salt, X is the water content of the concrete in the cover portion of the concrete structure. When the correction formula based on the water content is -25X + 180 and the salt content is 3 kg / m ³ , the correction formula based on the water content is calculated approximately as -20X + 150. When the concrete has a salt content other than the above, the above formula is used. A method for diagnosing the probability of corrosion or the degree of corrosion of reinforcing steel in a concrete structure, which is calculated by a prorated correction formula. 5. The correction formula according to claim 1, wherein when the correction based on the water content is further corrected based on the carbonation depth, Y is defined as the carbonation depth. = 8Y, and when the salt content is 3 kg / m ³ , the correction formula based on the carbonation depth is calculated approximately as 4Y, and when the concrete has a salt content other than the above, it is calculated from the above two formulas. A method of diagnosing the probability of corrosion or the degree of corrosion of reinforcing steel in a concrete structure, which is calculated by the correction formula. 6. A method for diagnosing the probability of corrosion or the degree of corrosion of reinforcing steel in a concrete structure by measuring a natural potential.
In correcting the measured natural potential in consideration of the water content, carbonation depth, and salt content of the concrete, the correction amount Z is such that W is the water content, A is the water content count, and t is the carbonation depth. is, when the B was counted carbonation depth, the correction amount Z = C-a × W + B × t a = 25-5 / 3 × ( amount of salt of the measurement results of non-carbonated portions: kg / ^{m 3} B) = 8−4 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ) C = 180−30 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³⁾ Corrosion of reinforcing bars in a concrete structure, wherein the corrosion probability or the degree of corrosion of reinforcing bars is evaluated with the corrected natural potential obtained by correcting the measured natural potential with this correction amount Z. Diagnosis method of probability or corrosion rate. 7. The method according to claim 6, wherein the corrosiveness of the reinforcing steel is evaluated by the corrected natural potential. The corrected natural potential E (mV) Corrosion degree Corrosion of the reinforcing steel −250 <E I Black scale without corrosion −350 < E≤-250 II State with slight spot rust on the surface -450 <E≤-350 III State with thin floating rust and rust attached to concrete E≤-450 IV, V Expandability Although there is rust in the concrete structure, remarkable expansive rust has been generated from a state where the cross-sectional defect is relatively small, and the corrosion probability or corrosion rate of the reinforcing steel in the concrete structure to be evaluated is classified into the state where the cross-sectional defect is present. Diagnostic method. 8. The probability of corrosion of reinforcing steel in a concrete structure.
Or measure the degree of corrosion and measure the natural potential of the concrete surface.
In the diagnosis and display of the results, the probability of corrosion or the degree of corrosion of the reinforcing steel in the concrete structure is calculated based on the measured natural potential, the water content of the concrete, the depth of carbonation,
The correction shall be made in consideration of the amount of salt, and the correction amount Z shall be
When W is the moisture content, A is the moisture content count, t is the carbonation depth, and B is the carbonation depth count, the correction amount Z = C−A × W + B × t A = 25−5 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ) B = 8−4 / 3 × (measurement result of salt content of uncarbonated portion: kg / m ³ ) C = 180-30 / 3 X (measured result of the salt content of the uncarbonated portion: kg / m ³ ), and the measured natural potential is used as a corrected natural potential obtained by correcting with the correction amount Z, and the corrected natural potential is calculated. The corrosion rate was evaluated by the following formula: Corrected spontaneous potential E (mV) Corrosion rate Corrosion state of reinforcing steel -250 <E I Black scale without corrosion -350 <E≤-250 II Slight spot rust on surface State -450 <E ≦ -350 III Light floating rust is generated and rust is attached to concrete. ≤-450 IV, V Expansive rust is generated, but the cross-sectional defect is relatively small and significant expansive rust is generated. Diagnosis device for corrosion probability or degree of corrosion of steel bars. 9. The display of a result according to claim 8, wherein the display of the reinforcing bar position is performed, and the display of the reinforcing bar position is determined based on a corrosion probability or a degree of corrosion. Diagnosis device for corrosion probability or degree of corrosion of reinforcing steel in concrete structures identified and displayed by classification. 10. The method according to claim 9, wherein, when identifying and indicating the position of the reinforcing bar based on the corrosion probability or the degree of corrosion, when the adjacent measurement points are in the same category of corrosion probability or corrosion degree, both sides are fixed. Diagnosis device for the probability of corrosion or degree of corrosion of reinforcing steel in concrete structures that distinguishes between the same categories.