JP2018017518A - Corrosion degree estimation method, corrosion degree estimation apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corrosion degree estimation method, a corrosion degree estimation device and a program for facilitating the formulation of maintenance priority of an aged structure by expanding the range in which the possibility of reinforcing bar corrosion can be estimated. SOLUTION: A measurement step S13 in which a reference electrode portion is pressed against a plurality of measurement points in a measurement range of a concrete member to measure a potential, and when the value of the measurement potential is larger than a first threshold value, a steel material is predetermined. First estimation step S14, which estimates that the steel material is not corroded with a probability and estimates that the steel material is corroded with a predetermined probability when the measured potential is equal to or less than the second threshold value smaller than the first threshold. In S16, when the value of the measurement potential is equal to or less than the first threshold value and the measurement potential is larger than the second threshold value, the cover thickness of the portion of the concrete member where the steel material is arranged is equal to or greater than the predetermined thickness. In some cases, it is characterized by having a second estimation step S18, which estimates that the steel material is not corroded with a predetermined probability. [Selection diagram] Fig. 2

Description

  The present invention relates to a corrosion degree estimation method, a corrosion degree estimation apparatus, and a program for estimating a corrosion degree of a steel material in concrete.

  In aged reinforced concrete structures, there is a desire to evaluate the quantitative progress of corrosion of steel materials (also referred to as reinforcing bars) in concrete. On the other hand, the self-potential measurement method is known as one of the non-destructive investigation methods to evaluate the possibility of corrosion of the reinforcing bar by measuring the potential of the reinforcing bar surface that changes due to corrosion of the reinforcing bar in the concrete. . The self-potential measurement method is utilized as a method for evaluating whether or not a reinforcing bar of a reinforced concrete structure is in a corrosive environment (see, for example, Patent Documents 1 to 3).

  The natural potential measurement method is defined by JSCE-E601 “Method for measuring natural potential in concrete structures” by the Japan Society of Civil Engineers. In addition, a standard defined as ASTM C876 by ASTM International (former name: American Society for Testing Materials) is also known as an official evaluation standard for a method for measuring a natural potential (see FIG. 8).

JP 2012-181130 A JP 2000-044364 A JP-A-10-212292

  However, in the evaluation standard defined as the above-mentioned ASTM C876, there is a region where the possibility of rebar corrosion is uncertain. Therefore, even if the natural potential is measured using the natural potential method for an aging reinforced concrete structure, there are problems that many measurement points included in an indeterminate region are generated.

  Furthermore, if there is an area where the possibility of rebar corrosion is uncertain, there is a problem that it becomes difficult to formulate maintenance priorities when planning the maintenance of aged reinforced concrete structures.

  The present invention has been made in order to solve the above-described problems, and it is possible to facilitate the creation of maintenance priorities for aged structures by expanding the range in which the possibility of rebar corrosion can be estimated. An object of the present invention is to provide a corrosion degree estimation method, a corrosion degree estimation device, and a program.

In order to achieve the above object, the present invention provides the following means.
The corrosion degree estimation method according to the first aspect of the present invention electrically connects a steel material embedded in a concrete member and one terminal of a potential measuring unit, and electrically connects the other terminal of the potential measuring unit. A step of measuring the potential by pressing the reference electrode portion against the plurality of measurement points in the measurement range of the concrete member and measuring the potential, and the value of the measured potential is greater than a first threshold value Is estimated that the steel material is not corroded with a predetermined probability, and when the measured potential is equal to or less than a second threshold value smaller than the first threshold value, the steel material has a predetermined probability. A first estimating step for estimating corrosion; and the measured potential value is equal to or less than a first threshold value, and the measured potential is greater than the second threshold value, the concrete member. The steel material in Has been the head thickness of the portion is characterized by having a, a second estimation step of estimating said steel does not corrode with a predetermined probability in the case where more than a predetermined thickness.

  The corrosion degree estimation apparatus according to the second aspect of the present invention includes a potential measurement unit, a connection unit that electrically connects a steel material embedded in a concrete member and one terminal of the potential measurement unit, and the potential measurement. The reference electrode part electrically connected to the other terminal of the part and pressed against the measurement point in the measurement range of the concrete member, and the cover thickness for measuring the cover thickness of the place where the steel material is arranged in the concrete member And when the measured potential value is greater than the first threshold value, the steel material is estimated not to corrode with a predetermined probability, and the measured potential value is less than the first threshold value. In the case of the second threshold value with a small value and below, it is estimated that the steel material is corroded with a predetermined probability, the value of the measured potential is below the first threshold value, and the measured potential is Is greater than the second threshold In the case of a threshold, there is provided an operation unit that estimates that the steel material is not corroded when the cover thickness measured by the cover thickness measuring unit is equal to or greater than a predetermined thickness. Features.

  In the program according to the third aspect of the present invention, one terminal is electrically connected to a steel material embedded in a concrete member, and the other terminal is pressed against a plurality of measurement points in the measurement range of the concrete member. Based on the potential measured by the potential measuring unit electrically connected to the unit and the cover thickness measured by the cover thickness measuring unit that measures the cover thickness of the portion where the steel material is disposed in the concrete member A program for estimating corrosion of the steel material, wherein the computer acquires the potential measured by the potential measuring unit, and obtains the cover thickness measured by the cover thickness measuring unit, and the measured If the value of the measured potential is greater than the first threshold value, it is estimated that the steel material has not been corroded with a predetermined probability, and the measured electric Is a second threshold value smaller than the first threshold value and below, a first estimation function for estimating that the steel material is corroded with a predetermined probability, and the measured potential value is the first value. When the measured potential is less than a threshold and the measured potential is larger than the second threshold, the steel material is measured when the cover thickness measured by the cover thickness measuring unit is greater than or equal to a predetermined thickness. And a second estimation function for estimating that the material is not corroded.

  According to the corrosion degree estimation method according to the first aspect of the present invention, the corrosion degree estimation apparatus according to the second aspect, and the program according to the third aspect, the steel material is based on the first threshold value and the second threshold value. For the range where the corrosion degree can be estimated, the corrosion degree of the steel material is estimated using the measured potential, and for the range where it is difficult to estimate the corrosion degree of the steel material using the measured potential, By estimating the corrosion degree of the steel material based on the cover thickness, it becomes easier to estimate the corrosion degree of the steel material.

  In the first aspect of the present invention, in the second estimating step, the cover thickness of the place where the steel material is disposed is a predetermined thickness or more, and the moisture content of the concrete of the concrete member is within a predetermined range. When both of these are satisfied, it is preferable to estimate that the steel material is not corroded.

  For the range where it is difficult to estimate the corrosion degree of the steel material with the potential measured in this way, the corrosion degree of the steel material is based on the cover thickness of the place where the steel material is placed in the concrete member and the moisture content of the concrete of the concrete member. It becomes easier to estimate the corrosion degree of the steel material by estimating.

In the first aspect of the present invention, in the second estimating step, the cover thickness of the place where the steel material is disposed is a predetermined thickness or more, and the moisture content of the concrete of the concrete member is within a predetermined range. The sand is not exposed on the concrete surface of the concrete member,
It is preferable to estimate that the steel material is not corroded when the concrete member satisfies all of the fact that there is no cracking or peeling.

  In the second aspect of the present invention, the method further comprises a moisture content measuring unit that measures the moisture content of the measurement range in the concrete member, and the computing unit has the measured potential value equal to or less than a first threshold value. And when the measured potential is larger than the second threshold value, the cover thickness measured by the cover thickness measuring unit is equal to or greater than a predetermined thickness, and the moisture content measuring unit When the measured moisture content is within a predetermined range, it is preferable to estimate that the steel material is not corroded.

  In the third aspect of the present invention, the acquisition function includes a moisture content acquisition function for acquiring the moisture content from a moisture content measuring unit that measures the moisture content of the measurement range in the concrete member. When the measured potential value is equal to or less than a first threshold value and the measured potential is greater than the second threshold value, the estimation function is configured to measure the fogging thickness measured by the fogging thickness measuring unit. It is preferable to estimate that the steel material is not corroded when the thickness is equal to or greater than a predetermined thickness and the water content measured by the water content measuring unit is within a predetermined range.

  In the range where it is difficult to estimate the corrosion degree of the steel material with the measured potential, the cover thickness of the part where the steel material is arranged in the concrete member, the moisture content of the concrete of the concrete member, the sand content is exposed, and the crack By estimating the corrosion degree of the steel material based on the peeling, it becomes easier to estimate the corrosion degree of the steel material.

  According to the corrosion degree estimation method, the corrosion degree estimation apparatus, and the program of the present invention, the range in which it is difficult to estimate the corrosion degree of the steel material at the measured potential is based on the cover thickness of the portion where the steel material is disposed in the concrete member. In order to estimate the degree of corrosion of the steel material, the range in which the possibility of rebar corrosion can be estimated can be expanded, and the maintenance priority of an aged structure can be easily established.

It is a model diagram explaining one Embodiment of the corrosion degree estimation apparatus by this invention. It is a flowchart explaining the corrosion estimation method of the reinforcing bar by the corrosion degree estimation apparatus of FIG. It is a schematic diagram explaining the example of arrangement | positioning of the measurement point in the measurement range of a reinforced concrete structure, and the electric potential distribution map (equivalent electric potential map) created by a measurement. It is a figure explaining the outline | summary of the reinforced concrete structure which estimated the corrosion. It is a table | surface showing the estimation result of corrosion. It is a table | surface explaining the response | compatibility with the condition of a corrosion grade and a reinforcing bar. It is a schematic diagram explaining other embodiment of the corrosion degree estimation apparatus of FIG. It is a table | surface explaining the evaluation criteria prescribed | regulated as ASTMC876.

  A corrosion degree estimation method, a corrosion degree estimation apparatus, and a program according to an embodiment of the present invention will be described with reference to FIGS. In this embodiment, when estimating and evaluating whether or not the reinforcing bar (steel material) 51 of the reinforced concrete structure (concrete member) 50 is corroded using the corrosion degree estimation method, the corrosion degree estimation apparatus, and the program of the present invention. It applies to and explains. Here, examples of the reinforced concrete structure 50 include buildings made of reinforced concrete and structures such as bridges.

  Further, in the present embodiment, description will be made by applying to an example in which a natural potential (potential) is measured using a natural potential measurement method defined as JSCE-E601 “Method for Measuring Natural Potential in Concrete Structures”.

  As shown in FIG. 1, the corrosion degree estimation apparatus 1 according to the present embodiment includes a potentiometer (potential measurement unit) 10, a connection unit 11, a probe (reference electrode unit) 12 used for measuring a natural potential, and a reinforcing bar. An estimation unit (calculation unit) 20 that estimates 51 corrosion, a moisture content measurement unit 31, and a cover thickness measurement unit 32 are mainly provided.

  The potentiometer 10, the connecting portion 11, and the probe 12 may be any one that can perform the natural potential measuring method defined as JSCE-E601 “Spontaneous Potential Measuring Method in Concrete Structures”, and is a known commercially available device. Can be used. In the description of the present embodiment, the description will be made based on the natural potential measured using canin + of Prosec.

  The potentiometer 10 has a connection portion 11 connected to one terminal and a probe 12 connected to the other terminal. The potentiometer 10 is a natural object of the rebar 51 that is a measurement object located in the measurement range set in the reinforced concrete structure 50. It is used for measuring the potential difference.

  The connection part 11 peels off the concrete on the surface of the reinforced concrete structure 50, and one end is electrically connected to the exposed reinforcing bar 51, and the other end is connected to the terminal of the potentiometer 10. It is what is done. For example, one end is a clip-like end sandwiching the reinforcing bar 51, and the other end is a connector connected to the terminal of the potentiometer 10, and a lead wire capable of conducting an electrical signal between the two ends. Can be given as an example.

  The probe 12 has a reference electrode inside, and is pressed against the concrete surface where the reinforcing bar 51 to be measured is located in the measurement range set in the reinforced concrete structure 50. As the reference electrode, any of a saturated copper sulfate electrode, a saturated calomel electrode, a saturated silver chloride electrode, and a lead electrode specified in JSCE-E601 “Method for Measuring Natural Potential in Concrete Structures” may be used.

  The estimation unit 20 acquires the natural potential measured by the potentiometer 10 and estimates the corrosion of the reinforcing bar 51 as the measurement target. In the present embodiment, description will be made by applying to an example in which the estimation unit 20 is a computer having a CPU (Central Processing Unit), ROM, RAM, input / output interface and the like. The program stored in the storage device such as the ROM described above causes the CPU to function as the calculation unit 21 and the input / output interface or the like to function as the acquisition unit 22.

  The calculation unit 21 includes a natural potential measured by the potentiometer 10, a moisture content measured by the moisture content measurement unit 31, a fog thickness measured by the fog thickness measurement unit 32, exposure of sand on the concrete surface, and This is to estimate whether or not the reinforcing bar 51 is corroded based on cracking or peeling of the concrete surface, and implements the first estimation function and the second estimation function. The details of specific calculation processing by the first estimation function and the second estimation function will be described later.

  The acquisition unit 22 acquires the natural potential measured by the potentiometer 10, the water content measured by the water content measurement unit 31, and the cover thickness measured by the cover thickness measurement unit 32. It also realizes the acquisition function. A specific method of acquiring the natural potential, the moisture content, and the cover thickness from the potentiometer 10, the moisture content measuring unit 31, and the cover thickness measuring unit 32 is to acquire via wired or wireless communication. In addition, a known information acquisition method such as a method of acquiring via a portable recording medium can be used, and the method is not limited to a specific method.

  In the present embodiment, the potentiometer 10 and the estimation unit 20 are described as applied to an example in which they are housed in separate housings. However, the potentiometer 10 and the estimation unit 20 are housed in one housing. There may be, and the format is not particularly limited.

  The moisture content measuring unit 31 measures moisture contained in the concrete in the reinforced concrete structure 50. A known measuring device can be used as the moisture content measuring unit 31, and the measuring method thereof is not particularly limited. For example, a concrete mortar moisture meter HI-520 from Ketto Scientific Research Institute, Inc. can be used.

  The cover thickness measuring unit 32 measures the cover thickness in the reinforced concrete structure 50, that is, the thickness from the reinforcing bar 51 to the concrete surface. A known measuring device can be used as the cover thickness measuring unit 32, and the measuring method and the like are not particularly limited.

Next, a method for estimating corrosion of the reinforcing bar 51 in the corrosion degree estimation apparatus 1 having the above-described configuration will be described with reference to FIGS.
First, an operation of confirming whether the reinforcing bars 51 to be measured have electrical continuity with each other is performed (S10). When the electrical continuity is confirmed, water is sprayed onto the concrete surface in the measurement range set in the reinforced concrete structure 50 (S11). In the watering operation, water is sprayed and sprayed before measuring the natural potential so that the concrete surface becomes wet. However, the work is performed so that floating water is not generated on the concrete surface.

  Thereafter, as a preparation for the corrosion degree estimation apparatus 1, a connection between the potentiometer 10 and the connection portion 11 and a connection between the potentiometer 10 and the probe 12 are performed (S12). As shown in FIG. 1, the end portion of the connecting portion 11 is electrically connected to a reinforcing bar 51 to be measured. At this time, when the surface of the reinforcing bar 51 is covered with an insulating material such as rust, the connecting part 11 is attached so as to be electrically connected to the reinforcing bar 51 after the insulating material is removed.

  Then, the potentiometer 10 performs an operation of measuring the natural potential in the measurement range set in the reinforced concrete structure 50 (measurement step: S13). For example, as shown in FIG. 3, the natural potential is measured at a plurality of measurement points 55 so that a potential distribution diagram (equivalent potential diagram) can be drawn along the reinforcing bars 51 arranged in the measurement range. It is preferable that the arrangement position of the reinforcing bar 51 is grasped in advance using a commercially available reinforcing bar probe.

  Further, when measuring the natural potential, water is contained in a sponge or the like disposed at the end of the probe 12 (reference electrode) pressed against the concrete surface, and the probe 12 is pressed against the measurement point 55. When measuring using canin + of Prosec Corp., the self-potential may be measured by pressing the stick-shaped probe 12 at each measurement point 55, or the wheel-shaped probe 12 is rotated on the line where the measurement points 55 are aligned. The self-potential may be measured by pressing it.

  The natural potential measured by the potentiometer 10 is acquired by the acquisition unit 22 to the estimation unit 20. The acquisition of the natural potential may be performed every time the natural potential is measured at the measurement point 55, or the value of the natural potential measured by the potentiometer 10 is stored, and a plurality of natural potentials are collectively collected by the estimation unit 20. May be obtained.

  The estimation unit 20 that has acquired the measured natural potential performs a process of determining whether or not the value of the natural potential measured by the calculation unit 21 is larger than the first threshold (first estimation step: S14). As the value of the natural potential used for the determination, the value of the natural potential selected as representing the measurement range among the natural potentials measured at the plurality of measurement points 55 in the measurement range is used. Various methods can be used as a representative method for selecting a natural potential, and the method is not particularly limited.

  In this embodiment, the first threshold value is -200 mV according to the evaluation standard of ASTM C 876 and applied to an example in which the second threshold value described later is -350 mV. Values described in the evaluation criteria may be used, and the values are not limited.

  When it is determined that the value of the natural potential measured in the determination of S14 is larger than the first threshold (in the case of YES), the calculation unit 21 corrodes the rebar 51 with a probability of 90% or more within the measurement range. It is estimated that there is not (S15).

  When the value of the natural potential measured in the determination of S14 is determined to be equal to or smaller than the first threshold value (in the case of NO), the calculation unit 21 determines whether the value of the measured natural potential is equal to or smaller than the second threshold value. (First estimation step: S16). When it is determined that the measured natural potential value is equal to or less than the second threshold value (in the case of YES), the calculation unit 21 estimates that the reinforcing bar 51 is corroded with a probability of 90% or more within the measurement range (S17). .

  When it is determined that the value of the natural potential measured in the determination of S16 is greater than the second threshold value (in the case of NO), the calculation unit 21 determines that the cover thickness measured within the measurement range is the predetermined thickness. The process which determines whether it is above is performed (2nd estimation step: S18). Examples of the predetermined thickness include the design cover thickness in the reinforced concrete structure 50. That is, the calculation unit 21 performs a process of determining whether or not the cover thickness measured within the measurement range is equal to or greater than the design cover thickness.

  When the cover thickness measured in the determination of S18 is determined to be less than the design cover thickness (in the case of NO), the calculation unit 21 corrodes the reinforcing bar 51 with a probability of 90% or more within the measurement range. (S17).

  When it is determined that the cover thickness measured in the determination of S18 is equal to or greater than the design cover thickness (in the case of YES), the calculation unit 21 determines that the moisture content measured within the measurement range is within the predetermined range. Processing for determining whether or not there is present (second estimation step: S19). Examples of the predetermined range include 4% or more and 7% or less, preferably 4% or more and 6% or less, and more preferably 4.5% or more and 5.5% or less.

  When it is determined that the moisture content measured in the determination of S19 is outside the predetermined range (in the case of NO), the calculation unit 21 estimates that the reinforcing bar 51 is corroded with a probability of 90% or more within the measurement range (S17). ).

  When it is determined that the moisture content measured in the determination of S19 is within the predetermined range (in the case of YES), the calculation unit 21 determines whether sand or the like is not exposed on the concrete surface within the measurement range. A determination process is performed (second estimation step: S20). The exposure of sand or the like means that the cement paste on the concrete surface is powdered and the sand is exposed.

  In addition, the calculating part 21 may determine whether the sand content is not exposed by analyzing the image which image | photographed the concrete surface of the measurement range, and the sample which is a part of concrete surface of the measurement range. And analyzing this sample to determine whether the sand is not exposed or not based on whether the sand is in contact with the concrete surface in the measurement range. May be. Further, the result of confirming whether or not sand or the like is exposed on the concrete surface in the measurement range may be determined based on the input result input to the calculation unit 21, and the determination method is limited. Not what you want.

  When it is determined in S20 that sand is exposed on the concrete surface within the measurement range (in the case of NO), the calculation unit 21 corrodes the rebar 51 with a probability of 90% or more within the measurement range. Presumed to be present (S17).

  When it is determined in the determination of S20 that no sand or the like is exposed on the concrete surface within the measurement range (in the case of YES), it is determined whether or not the concrete surface in the measurement range is cracked or peeled off. Processing is performed (second estimation step: S21).

  The calculation unit 21 may determine whether or not there is cracking or peeling by analyzing an image obtained by photographing the concrete surface in the measurement range. The result of confirming whether or not there is peeling may be determined based on the input result input to the calculation unit 21, and the determination method is not limited.

  When it is determined in S21 that the concrete surface in the measurement range has cracks or peeling (in the case of NO), the calculation unit 21 estimates that the reinforcing bar 51 is corroded with a probability of 90% or more within the measurement range. (S17).

  If it is determined in S21 that the concrete surface in the measurement range is not cracked or peeled off (in the case of YES), the calculation unit 21 indicates that there is no corrosion in the rebar 51 with a probability of 90% or more within the measurement range. Estimate (S15).

  Next, an example in which corrosion of the reinforcing bar 51 is estimated in the corrosion degree estimation apparatus 1 having the above configuration will be described with reference to FIGS. 4 to 6. FIG. 4 is a diagram for explaining the outline of the reinforced concrete structure 50 on which the corrosion is estimated, and FIG. 5 is a table showing the corrosion estimation results.

  As shown in FIG. 4, the reinforced concrete structure 50 on which the corrosion has been estimated includes four buildings: an A building, a B building, a C building, and a D building. The area where these buildings are located, the year of construction, the year when the survey (estimation) was conducted, and the elapsed time are as shown in FIG. RC in the structure and scale means reinforced concrete, (0 +2) is 2 stories without basement, (0 +4) is 4 stories without basement, (-1 + 2) means two stories on the first basement floor.

  As for Building A, as shown in FIG. 1 and no. No. 2 for 2 locations and B building. 1 to No. For 5 locations up to 5, C building, No. 1 to No. 5 locations up to 5, No. 1 and no. 2 are estimated at two locations.

  The second evaluation criterion in FIG. 5 means the criterion used in the determination of the second estimation steps S18 to S21. (1) is whether or not the moisture content measured within the measurement range is within a predetermined range, and (2) is whether or not sand is exposed on the concrete surface within the measurement range, (3) is whether or not the concrete surface in the measurement range is free from cracks or peeling, and (4) is whether or not the cover thickness measured within the measurement range is greater than or equal to a predetermined thickness.

  The first evaluation criterion in FIG. 5 means the criterion used in the determination of the first estimation steps S14 and S16. Further, the visual corrosion grade is determined by visualizing the reinforcing bar 51 to determine which of the grades shown in the table of FIG. Here, grade I and grade II correspond to no corrosion (sound), and grade III and grade IV correspond to corrosion.

  When the plurality of estimation results shown in FIG. 5 are evaluated, when the corrosion of the reinforcing bar 51 is estimated using only the second evaluation criterion, the estimation result is 73% of the probability when compared with the degree of corrosion of the reinforcing bar 51 by visual observation. The results are consistent. On the other hand, when the corrosion of the reinforcing bar 51 is estimated using the second evaluation standard for the measurement position determined to be indeterminate in the first evaluation standard, the estimation result and the visual confirmation result with a probability of 93%. And the results are consistent.

  According to said structure, about the range which can estimate the corrosion degree of the reinforcing bar 51 based on a 1st threshold value and a 2nd threshold value, the corrosion degree of the reinforcing bar 51 is estimated using the measured electric potential, and the reinforcing bar 51 is measured with the measured electric potential. In the range where it is difficult to estimate the degree of corrosion, the cover thickness of the reinforced concrete structure 50 where the reinforcing bars 51 are arranged, the moisture content of the concrete of the reinforced concrete structure 50, the sand content is exposed, and cracking and peeling are considered. By estimating the corrosion degree of the reinforcing bar 51 based on this, it becomes easier to estimate the corrosion degree of the reinforcing bar 51.

  In other words, it is possible to widen the range in which the possibility of rebar corrosion can be estimated, and it is possible to easily set the maintenance priority of an aged structure. Therefore, the estimation result is used as a quantitative deterioration progress degree of the reinforcing bar corrosion of the reinforced concrete structure 50, and the basis for establishing the maintenance priority and the diagnostic accuracy of the remaining life of the reinforced concrete structure 50 including the building are improved. Can be achieved.

  In addition, since the degree of deterioration of the reinforced concrete structure 50 can be quantified, it becomes possible to identify the reinforced concrete structure 50 that needs to be refurbished for the time being, and it is easy to reduce the required annual investment cost for the reinforced concrete structure 50. Become.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the description has been made by applying the example in which the connecting part 11 is electrically connected to the reinforcing bar 51 that is exposed to the outside and is exposed to the outside. Other members that are electrically connected to 51 may be used. Specifically, as shown in FIG. 7, a sash frame 56, which is a metal member installed around an opening such as an entrance, is often electrically connected to the reinforcing bar 51. You may make it connect the connection part 11 to this sash frame 56 electrically.

  DESCRIPTION OF SYMBOLS 1 ... Corrosion degree estimation apparatus, 10 ... Potentiometer (potential measurement part), 11 ... Connection part, 12 ... Probe (reference | reference electrode part), 20 ... Estimation part (calculation part), 21 ... Calculation part, 31 ... Water content measurement , 32 ... Cover thickness measurement part, 50 ... Reinforced concrete structure (concrete member), 51 ... Reinforcement (steel), S13 ... Measurement step, S14 ... First estimation step, S16 ... First estimation step, S18 ... Second Estimation step, S19 ... second estimation step, S20 ... second estimation step, S21 ... second estimation step

Claims (7)

A steel electrode embedded in the concrete member and one terminal of the potential measurement unit are electrically connected, and a plurality of reference electrode portions electrically connected to the other terminal of the potential measurement unit are included in the measurement range of the concrete member. A measurement step of measuring the potential by pressing the reference electrode portion to the measurement point
When the value of the measured potential is larger than the first threshold value, it is estimated that the steel material is not corroded with a predetermined probability, and the measured potential is a second value smaller than the first threshold value. In the case of the threshold value and the following, a first estimation step for estimating that the steel material is corroded with a predetermined probability;
When the measured potential value is less than or equal to the first threshold value and the measured potential is greater than the second threshold value, the cover thickness of the portion where the steel material is disposed in the concrete member is A second estimation step for estimating that the steel material is not corroded with a predetermined probability when the thickness is equal to or greater than a predetermined thickness;
A method for estimating the degree of corrosion, comprising: In the second estimating step,
The cover thickness of the place where the steel material is disposed is a predetermined thickness or more,
The concrete moisture content of the concrete member is within a predetermined range;
The corrosion degree estimation method according to claim 1, wherein when both of the conditions are satisfied, the steel material is estimated not to be corroded. In the second estimating step,
The cover thickness of the place where the steel material is disposed is a predetermined thickness or more,
The concrete moisture content of the concrete member is within a predetermined range;
That no sand is exposed on the concrete surface of the concrete member;
The concrete member is not cracked or peeled off,
The corrosion degree estimation method according to claim 1, wherein if all of the above are satisfied, it is estimated that the steel material is not corroded. A potential measurement unit;
A connecting portion for electrically connecting a steel material embedded in a concrete member and one terminal of the potential measuring portion;
A reference electrode unit electrically connected to the other terminal of the potential measuring unit and pressed against a measurement point in the measurement range of the concrete member;
A cover thickness measuring unit for measuring the cover thickness of the place where the steel material is disposed in the concrete member;
When the value of the measured potential is larger than the first threshold value, it is estimated that the steel material is not corroded with a predetermined probability, and the measured potential is a second value smaller than the first threshold value. If the threshold and below, the steel is estimated to corrode with a predetermined probability,
When the measured potential value is less than or equal to the first threshold value and the measured potential is greater than the second threshold value, the cover thickness measured by the cover thickness measuring unit is predetermined. When the thickness is greater than or equal to the thickness, the computing unit estimates that the steel material is not corroded,
Corrosion degree estimation device characterized by that. A water content measurement unit for measuring the water content of the measurement range in the concrete member;
When the measured potential value is less than or equal to a first threshold value and the measured potential is greater than the second threshold value, the computing unit measures the cover thickness measurement unit. It is estimated that the steel material is not corroded when the cover thickness is equal to or greater than a predetermined thickness and the water content measured by the water content measuring unit is within a predetermined range. Item 5. The corrosion degree estimation apparatus according to Item 4. One terminal is electrically connected to a steel material embedded in a concrete member, and the other terminal is electrically connected to a reference electrode unit pressed against a plurality of measurement points in the measurement range of the concrete member. A program for estimating corrosion of the steel material based on the measured potential and the cover thickness measured by the cover thickness measuring unit that measures the cover thickness of the portion where the steel material is disposed in the concrete member. ,
An acquisition function for causing a computer to acquire the potential measured by the potential measuring unit and to acquire the cover thickness measured by the cover thickness measuring unit;
When the value of the measured potential is larger than the first threshold value, it is estimated that the steel material is not corroded with a predetermined probability, and the measured potential is a second value smaller than the first threshold value. In the case of the threshold and the following, the first estimation function that estimates that the steel material is corroded with a predetermined probability;
When the measured potential value is less than or equal to the first threshold value and the measured potential is greater than the second threshold value, the cover thickness measured by the cover thickness measuring unit is predetermined. A second estimation function for estimating that the steel material is not corroded when the thickness is equal to or greater than the thickness;
A program characterized by realizing. The acquisition function includes a moisture content acquisition function for acquiring the moisture content from a moisture content measurement unit that measures the moisture content of the measurement range in the concrete member,
The second estimation function is measured by the cover thickness measuring unit when the measured potential value is equal to or less than a first threshold value and the measured potential is greater than the second threshold value. Further, when the cover thickness is equal to or greater than a predetermined thickness and the water content measured by the water content measuring unit is within a predetermined range, it is estimated that the steel material is not corroded. The program according to claim 6.