JP6158961B1 - Steel material potential measuring method and steel material potential measuring device - Google Patents

Abstract

An object of the present invention is to provide a method and apparatus for efficiently measuring the potential of a steel material in a concrete structure in which the steel material is embedded. A steel material potential measuring method according to the present invention is a steel material potential measuring method for measuring a potential of a steel material 11b embedded in a concrete structure 11 by using a steel material potential measuring device 1, and the steel material potential measuring device 1 Is between the reference contact portion 2, the reference electrode unit 3 having the reference electrodes 32 and the reference electrode holding portion 32 for holding the reference electrodes 31, and the reference contact portion 2 and each of the reference electrodes 31. A plurality of reference electrodes 31 are arranged in two dimensions at intervals from each other, and the reference electrode unit 3 is moved along the surface of the concrete structure 11. In this case, the potential difference between the reference contact portion 2 and each of the plurality of verification electrodes 31 is measured by sequentially arranging them on the plurality of verification surfaces 11d. [Selection] Figure 1

Description

  The present invention relates to a steel material potential measuring method and a steel material potential measuring device for measuring the potential of a steel material in a concrete structure in which the steel material is embedded.

  In concrete structures in which steel materials are embedded, such as reinforced concrete, corrosion of steel materials due to deterioration over time has become a problem. As a method for investigating the corrosion state of a steel material embedded in a concrete structure, for example, Patent Document 1 discloses a method of detecting a corrosion site of a steel material by measuring a difference in natural potential between two steel materials in the concrete. It is disclosed. In the corrosion detection method disclosed in Patent Document 1, as shown in FIG. 6 (a), two main detection ends 101a and 101b having electrodes are brought into contact with the surface of the concrete 103 at a constant interval to thereby measure the potential. 100, the difference between the natural potentials at two locations of the steel material 102 in the concrete 103 is measured. Then, as shown in FIGS. 6A and 6B, one book detection end 101b is moved and sequentially brought into contact with the surface of the concrete 103, and the difference in natural potential is measured. A location where a natural potential relatively low with respect to the natural potential at the detection end 101a is detected is found, and a corrosion location of the steel material is specified.

JP-A-10-212292

  However, in the corrosion detection method disclosed in Patent Document 1, since this detection end 101b needs to be brought into contact with the surface located directly above the steel material, the position where the steel material is embedded beforehand by a reinforcing bar probe or the like is used. It is necessary to check and put a marker on the surface of the concrete structure, such as making a ruled line. Then, as shown in FIG. 6A and FIG. 6B, the detection end 101b is moved over the entire region of the steel material 102 for each of the embedded steel materials 102 one by one. It is necessary to measure the potential difference. Therefore, for example, when investigating the corrosion state of steel in a concrete structure used in a huge structure such as a bridge, the position of the buried steel is examined over a very wide area to be investigated, and the concrete structure Since a marker is attached to the surface of an object and then a large number of measurement points have to be measured, there is a problem that enormous labor and time are consumed. Furthermore, there is a problem that it becomes difficult to grasp the whole image of the investigation object by limiting the investigation range to be small in order to save such labor and time. Further, in this type of corrosion detection method, in order to obtain good electrical contact between the detection ends 101a and 101b and the surface of the concrete 103, it is common to spray the surface of the concrete 103 for about 30 minutes. The measurement of the entire area takes time, and the wet condition of the surface changes until the measurement of the entire area is completed. Therefore, the measurement conditions vary depending on the area, and accurate measurement results cannot be obtained. There is.

  This invention is made | formed in view of this problem, and it aims at providing the method and apparatus for measuring the electric potential of the steel materials efficiently in the concrete structure in which the steel materials were embed | buried.

  The steel material potential measuring method of the present invention is a steel material potential measuring method for measuring the potential of a steel material embedded in a concrete structure using a steel material potential measuring device, wherein the steel material potential measuring device contacts a reference position. A reference electrode unit having a reference contact part, a plurality of reference electrodes that contact the surface of the concrete structure, a reference electrode holding part that holds the plurality of reference electrodes, the reference contact part, and the plurality of reference electrodes Each of the plurality of reference electrodes is connected to the reference contact part and each of the plurality of reference electrodes, and each of the plurality of reference electrodes is connected to the reference electrode holding part. Two-dimensionally arranged in a plane including a first direction and a second direction orthogonal to each other, spaced apart from each other, the steel material potential measurement method contacts the reference contact portion with the reference position. Placing the reference electrode unit on the verification surface of the concrete structure to bring the plurality of verification electrodes into contact with the surface in the verification surface; and And measuring a potential difference between each of the plurality of verification electrodes, the verification electrode unit is moved along the surface of the concrete structure, and sequentially disposed on the plurality of verification surfaces, A potential difference between the reference contact portion and each of the plurality of verification electrodes is measured for each of the plurality of verification surfaces.

  Further, it is preferable to include a step of calibrating the measured potential difference for each of the plurality of verification electrodes in order to correct a shift in electrode potential unique to the verification electrode.

  Preferably, the method further includes a step of obtaining a statistical value of the potential difference for each of the plurality of verification electrodes for each of the plurality of verification surfaces.

  In addition, the arrangement interval of the plurality of verification electrodes is smaller than the distance between two steel materials embedded separately from the concrete structure, and the interval between the verification electrodes arranged most apart is the concrete structure. It is preferable that the distance is larger than the distance between two steel materials embedded in the object.

  The reference electrode holding portion is formed in a substantially rectangular shape having a pair of first sides extending along the first direction and a pair of second sides extending along the second direction, A plurality of collation electrodes are arranged in a substantially equidistant matrix along the first direction and the second direction on the collation electrode holding portion, and are arranged on the first side and the first side. Both the spacing between the near reference electrodes and the spacing between the second side and the nearest matching electrode to the second side are arrangements of the matching electrodes in the first direction and the second direction. Preferably, it is approximately half of the interval.

  The steel material potential measuring device of the present invention is a steel material potential measuring device used for measuring the potential of a steel material embedded in a concrete structure, wherein a reference contact portion that contacts a reference position and the surface of the concrete structure A reference electrode unit having a plurality of reference electrodes in contact with each other, a reference electrode holding part for holding the plurality of reference electrodes, and the reference contact part and each of the plurality of reference electrodes, and the reference contact part And a potential difference measuring device that measures a potential difference between each of the plurality of verification electrodes, and each of the plurality of verification electrodes has a first direction and a second direction orthogonal to the verification electrode holding unit. It is characterized in that they are arranged two-dimensionally at intervals in a plane including the direction.

  In addition, the arrangement interval of the plurality of verification electrodes is smaller than the distance between two steel materials embedded separately from the concrete structure, and the interval between the verification electrodes arranged most apart is the concrete structure. It is preferable that the distance is larger than the distance between two steel materials embedded in the object.

  The reference electrode holding portion is formed in a substantially rectangular shape having a pair of first sides extending along the first direction and a pair of second sides extending along the second direction, A plurality of collation electrodes are arranged in a substantially equidistant matrix along the first direction and the second direction on the collation electrode holding portion, and are arranged on the first side and the first side. Both the spacing between the near reference electrodes and the spacing between the second side and the nearest matching electrode to the second side are arrangements of the matching electrodes in the first direction and the second direction. Preferably, it is approximately half of the interval.

  Further, the steel material potential measuring device includes an information processing device, and the information processing device calibrates the measured potential difference for each of the plurality of reference electrodes in order to correct a deviation of the electrode potential specific to the reference electrode. It is preferable to be configured to do so.

  The steel material potential measuring device includes an information processing device, and the information processing device is configured to obtain a statistical value of the potential difference for each of the plurality of verification electrodes for each of the plurality of verification surfaces. It is preferable.

  According to the steel material potential measuring method and the steel material potential measuring device of the present invention, the potential of the steel material in the concrete structure in which the steel material is embedded can be efficiently measured.

It is a figure which shows one Embodiment of the steel material potential measuring apparatus used with the steel material potential measuring method of this invention. It is the figure which looked at the collation electrode unit of the steel material potential measuring device of Drawing 1 from the collation electrode side, (a) is a perspective view and (b) is a top view. It is a flowchart which shows one Embodiment of the steel material potential measuring method of this invention. It is a schematic diagram which shows one Embodiment of the steel-material electric potential measuring method of this invention, (a) has shown the state by which the reference electrode was contacted to the reference surface, and the collation electrode unit was arrange | positioned on the collation surface, (b ) Shows a state where the position where the verification electrode unit is arranged is sequentially changed, and (c) shows a state where the verification electrode unit is sequentially arranged over the entire surface of the concrete structure to be measured. Show. It is a figure which shows typically the electric potential difference distribution which linked | related the measured electric potential difference and the measured area | region obtained by the steel material electric potential measuring method which concerns on one Embodiment of this invention, (a) respond | corresponds to a collation electrode. (B) shows the distribution for each collation surface. (A) is a side view which shows typically the steel-material corrosion measuring apparatus used for the conventional corrosion detection method, (b) is a plane which shows typically the steel-material corrosion measuring apparatus used for the conventional corrosion detection method FIG.

  Hereinafter, a steel material potential measuring method and a steel material potential measuring device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  A steel material potential measuring method according to an embodiment of the present invention is a method of measuring the potential of a steel material embedded in a concrete structure using a steel material potential measuring device. As shown in FIG. 1, the concrete structure 11 to which the steel material potential measuring method of the present embodiment is applied is a structure in which a steel material 11b is embedded in concrete 11a. The concrete structure 11 is not particularly limited as long as it is a structure in which steel is embedded in concrete. For example, a bridge of a bridge over a river or the sea, a pier of a highway, a dam, etc. Giant civil engineering structures such as, buildings such as buildings. Moreover, as steel material 11b embed | buried in concrete 11a, in this embodiment shown by FIG. 1, the rebar arranged in the grid | lattice form is illustrated, However, The kind and magnitude | size of steel materials, and the arrangement method of steel materials are There is no particular limitation. From the potential of the steel material measured by the steel material potential measurement method of the present embodiment, for example, the corrosion state of the steel material and the surrounding state of the steel material can be determined, but the present invention is not limited to this, and the steel material to be measured Any state of the steel material can be determined as long as the potential of the steel material is significantly different. Hereinafter, the steel material potential measuring method of this embodiment is to measure the potential of the steel material (rebar) 11b in the concrete structure (wall portion) 11 in which the steel material (rebar) 11b is embedded in the concrete 11a bonded by cement. A description will be given based on an example used to determine the corrosion state of the steel material 11b.

<Steel material potential measuring device>
The steel material potential measuring device 1 used in the steel material potential measuring method of the present embodiment is used to measure the potential of the steel material 11b embedded in the concrete structure 11. More specifically, the steel material potential measuring device 1 measures the potential (natural potential or relative potential) of the steel material 11 b embedded in the concrete structure 11 from the surface of the concrete structure 11. And the corrosion state of the steel material 11b can be determined from the measured potential of the steel material 11b. As shown in FIG. 1, the steel material potential measuring device 1 of the present embodiment includes a reference contact portion 2 that contacts a reference position, a plurality of reference electrodes 31 that contact a surface of a concrete structure 11, and a plurality of reference electrodes 31. The reference electrode unit 3 having the reference electrode holding part 32 for holding the reference contact part 2 and each of the plurality of reference electrodes 31 are connected, and between the reference contact part 2 and each of the plurality of reference electrodes 31 And a potential difference measuring device 4 for measuring a potential difference. According to this steel material potential measuring device 1, the potential difference between the potential at the reference position and the natural potential of the steel material 11b located near (substantially below) the surface of the concrete structure 11 with which the verification electrode 31 contacts is a potential difference measuring device. 4 is measured. As will be described later, when the reference position is the steel material 11 b embedded in the concrete structure 11, the potential difference measured by the potential difference measuring device 4 indicates the natural potential of the steel material 11 b in the concrete structure 11. When the position is the surface of the concrete structure 11 (reference surface 11c), the potential difference measured by the potential difference measuring device 4 is the concrete where the reference electrode 31 contacts the natural potential of the steel material 11b in the vicinity of the reference surface 11c. The difference (relative potential) from the natural potential of the steel material 11b in the vicinity of the surface of the structure 11 is shown. For example, in the former case, when the natural potential of the steel material 11b is lower than a predetermined potential value (threshold), it is determined that the steel material 11b at that position may be corroded. In the latter case, if the natural potential of the steel material 11b on the surface in contact with the reference electrode 31 is lower than a predetermined potential difference (threshold) than the natural potential of the steel material 11b on the reference surface 11c, the steel material 11b at that position is It is determined that there is a possibility of corrosion. The natural potential of the steel material 11b is a potential of the steel material 11b in a state where no external potential is applied, and is a natural potential measured by a known natural potential measurement method.

<Reference contact area>
The reference contact portion 2 is a member that is in contact with a reference position having a reference potential with respect to the natural potential of the steel material 11b measured on the surface with which the verification electrode 31 contacts. Specifically, as shown in FIG. 1, when measuring the natural potential of the steel material 11b, the reference terminal 21 that is in contact with the steel material 11b serving as a reference position can be used as the reference contact portion 2. . When measuring the relative potential of the steel material 11b, the concrete structure is located in the vicinity of the cover thickness direction of the region of the steel material 11b having a reference natural potential (reference potential) (substantially above the region). The reference electrode 22 that is in contact with the surface of the object 11 (reference surface 11c) can be used as the reference contact portion 2. However, the reference contact portion 2 and the reference position may be other combinations as long as a reference potential can be obtained with respect to the natural potential of the steel material 11b measured on the surface with which the reference electrode 31 contacts.

  As shown in FIG. 1, the reference terminal 21 is in contact with a steel material 11 b embedded in the concrete structure 11 and is electrically connected to one or the other terminal of the potential difference measuring device 4 through a lead wire 6 such as a lead wire. Connected. As the reference terminal 21, a known alligator clip or the like can be used. However, the material and shape of the reference terminal 21 are not particularly limited as long as the steel material 11b and the potential difference measuring device 4 can be connected to each other. In addition, the position of the steel material 11b with which the reference terminal 21 is in contact can be arbitrarily selected from a healthy location where no corrosion or the like occurs.

  As shown in FIG. 1, the reference electrode 22 is in contact with the reference surface 11 c of the concrete structure 11, and is electrically connected to one or the other terminal of the potential difference measuring device 4 through a conducting wire 6 such as a lead wire. Connected. Although not shown, the reference electrode 22 includes an electrode body and a wet pad on the side in contact with the reference surface 11c. As the electrode body of the reference electrode 22, a known electrode such as a copper / copper sulfate electrode, a silver / silver chloride electrode, or a calomel electrode can be adopted. Further, the wet pad of the reference electrode 22 has a water injection / water retention function, and is configured such that the reference electrode 22 can be stably contacted and held on the surface of the concrete structure 11. The wet pad has a water retaining material such as a sponge, and is wetted with an electrolyte solution such as tap water or a calcium hydroxide solution. Since the reference electrode 22 includes the wet pad, the surface of the concrete structure 11 is reliably kept wet when the reference electrode 22 contacts the reference surface 11c, and the reference electrode 22 and the reference surface 11c are maintained. Good electrical contact with. In the present embodiment, the reference electrode 22 has a substantially rectangular parallelepiped shape in which a wet pad is laminated on a thin plate-like electrode body. However, the reference electrode 22 may have any shape or size as long as it can contact the reference surface 11c of the concrete structure 11 in order to use as a reference when measuring the potential difference with the potential difference measuring device 4. The present invention is not limited to the above-described embodiment. In the present embodiment, the reference electrode 22 is formed in a size that spans a plurality of steel materials 11b that are embedded separately. Thus, unlike the conventional method, the position of the steel material 11b embedded in the concrete structure 11 is searched for, and the labor for providing the reference electrode 22 immediately above the steel material 11b can be saved, and the reference potential can be obtained reliably and easily. . In addition, as the reference surface 11c, for example, a surface located in the vicinity of the cover thickness direction of the non-corroded region of the steel material 11b (substantially above the region) is arbitrarily selected from the surfaces of the concrete structure 11. Is done. However, the reference surface 11c may be the surface of the concrete structure 11 located in the vicinity of the cover thickness direction of the region of the steel material 11b having the reference natural potential, and the cover thickness of the slightly corroded region of the steel material 11b. The surface of the concrete structure 11 located in the vicinity of the vertical direction may be used. The size of the reference surface 11 c is defined by the size of the reference electrode 22.

<Reference electrode unit>
The collation electrode unit 3 includes a plurality of collation electrodes 31 and a collation electrode holding unit 32 that holds the plurality of collation electrodes 31, and a region of the steel material 11b having a natural potential to be measured with respect to a reference potential. Are arranged on the surface of the concrete structure 11 (matching surface 11d), which is located in the vicinity of the cover thickness direction in the vicinity of (in the vicinity of the region), the plurality of matching electrodes 31 are placed in the matching surface 11d. It is a member made to contact the some surface. In the verification electrode unit 3, as shown in FIGS. 2A and 2B, each of the plurality of verification electrodes 31 has a first direction X and a second direction orthogonal to the verification electrode holding portion 32. Are arranged two-dimensionally at intervals in a plane including the direction Y. Therefore, when the collation electrode unit 3 is arranged on the collation surface 11d, the plurality of collation electrodes 31 arranged in two dimensions are simultaneously brought into contact with the plurality of surfaces in the collation surface 11d. The natural potential or relative potential can be measured simultaneously. Thereby, the electric potential of the some area | region of the steel material 11b can be measured efficiently. As a result, it is possible to simultaneously determine the corrosion state of a plurality of regions of the steel material 11b, and to efficiently determine the corrosion state of the steel material 11b in the concrete structure 11 in which the steel material 11b is embedded. In addition, as the collation surface 11d, the concrete structure 11 is located in the vicinity of the cover thickness direction of the region of the steel material 11b to be measured from the surface of the concrete structure 11 (substantially directly above the region). The surface is arbitrarily selected. The size of the verification surface 11 d is defined by the size of the verification electrode unit 3.

  In the verification electrode unit 3, as long as the plurality of verification electrodes 31 are two-dimensionally arranged at intervals, the arrangement interval is not particularly limited, but as shown in FIG. The arrangement interval of the verification electrodes 31 is smaller than the distance between the two steel materials 11 b embedded in the concrete structure 11 so as to be separated from each other, and the interval between the verification electrodes 31 arranged in the most separated position is in the concrete structure 11. It is preferable that the distance is larger than the distance between the two steel materials 11b embedded in a separated manner. More specifically, among the plurality of verification electrodes 31 arranged in two dimensions, the distance between the centers of two verification electrodes 31 that are spaced apart with the shortest distance is the shortest distance. The distance between the centers of the two reference electrodes 31 that are smaller than the distance between the centers of the two steel materials 11b that are spaced apart and are the longest distance apart is the shortest distance between them. It is preferable that the distance is larger than the distance between the centers of the two steel materials 11b that are spaced apart. By arranging the plurality of verification electrodes 31 in this manner, when the verification electrode unit 3 is arranged on the verification surface 11d without checking the position where the steel material is embedded in advance by a reinforcing bar probe or the like, On the surface of the region where the plurality of steel materials 11b are embedded, the plurality of verification electrodes 31 come into contact with the surface in the verification surface 11d at intervals shorter than the distance between the plurality of steel materials 11b, or the natural potential of the plurality of steel materials 11b or Relative potential can be measured simultaneously without substantial leakage. As a result, the corrosion state distribution of the steel material 11b can be determined efficiently. In the present embodiment, the plurality of verification electrodes 31 are arranged along the first direction X and the second direction Y on the verification electrode holding portion 32 as shown in FIG. 2A and FIG. Spacing between reference electrodes 31 arranged in a substantially equidistant matrix (or grid) and spaced apart with the shortest distance in the first and second directions X and Y (between the electrode centers) Distance (d1) is smaller than the distance d3 (see FIG. 1) between the two steel materials 11b, and the distance between the reference electrodes 31 (the electrode center) that is the longest distance apart in the first and second directions X and Y The distance (distance) D1 is arranged to be larger than the distance d3 (see FIG. 1) between the two steel materials 11b. Therefore, in the arrangement of the collation electrodes 31 of the present embodiment, the potential distribution of the steel material 11b can be efficiently measured with substantially no leakage in both the first and second directions X and Y. The verification electrode unit 3 of the present embodiment is provided with 3 × 3 = 9 verification electrodes, but the number is arbitrarily set according to the surface of the target concrete structure 11. For example, 4 × 4 = 16, 5 × 5 = 25, 3 × 4 = 12, 3 × 5 = 15, and the like. Further, as described above, the distance d1 and the distance D1 are determined according to the distance d3. For example, d1 = 50 to 200 mm (100 mm in the present embodiment), D1 = 150 to 500 mm or more (200 mm in the present embodiment). ).

  The collation electrode holding part 32 is a member that holds a plurality of two-dimensionally arranged collation electrodes 31 in an insulated state. In the present embodiment, the verification electrode holding unit 32 has a pair of first sides 33, 33 and second extending along the first direction X, as shown in FIGS. 2 (a) and 2 (b). Are formed in a substantially rectangular shape having a pair of second sides 34 extending along the direction Y. The collation electrode holding unit 32 is configured such that the distance d2 between the first side 33 and the collation electrode 31 closest to the first side 33 and the collation electrode closest to the second side 34 and the second side 34 The distance d2 between the first and second electrodes 31 is approximately half the array distance d1 of the matching electrodes 31 in the first direction X and the second direction Y. Therefore, as shown in FIG. 4B, the reference electrode unit 3 is moved along the surface of the concrete structure 11 and is sequentially arranged on the adjacent reference surface 11d. Each can be brought into contact with the surface of the concrete structure 11 at substantially equal intervals. Thereby, it becomes easy to measure the distribution of the natural potential or the relative potential of the steel material 11b at substantially equal intervals, and the distribution of the corrosion state of the steel material 11b in the concrete structure 11 can be accurately determined in a short time.

  In this embodiment, as shown in FIG. 1, the reference electrode holding portion 32 is formed to have a size that spans a plurality of steel materials 11 b that are embedded in the concrete structure 11 while being separated from each other. The size is not particularly limited as long as the plurality of verification electrodes 31 arranged in the size can be held in a state of being insulated from each other, and the size is not particularly limited. The size can be arbitrarily set accordingly. Further, in this embodiment, the collation electrode holding unit 32 is formed of an insulating resin material, but is not particularly limited as long as the plural collation electrodes 31 can be held in an insulated state. It may be formed of other materials.

<Reference electrode>
As shown in FIG. 1, the verification electrode 31 is an electrode that is in contact with the surface in the verification surface 11d described above. The verification electrode 31 is in contact with the surface in the verification surface 11d and is connected to the other or one terminal of the potential difference measuring device 4 through a conductive wire 6 such as a lead wire. Although not shown, the verification electrode 31 includes an electrode body and a wet pad disposed on the side in contact with the surface of the concrete structure 11. A known electrode such as a copper / copper sulfate electrode, a silver / silver chloride electrode, or a calomel electrode can be used for the electrode body of the verification electrode 31. Further, the wetting pad of the verification electrode 31 has a water injection / water retention function, and is configured such that the verification electrode 31 can come into stable electrical contact with the surface of the concrete structure 11. The wet pad has a water retaining material such as a sponge, and is wetted with an electrolyte solution such as tap water or a calcium hydroxide solution. Since the collation electrode 31 includes the wet pad, when the collation electrode 31 contacts the surface of the concrete structure 11, the surface of the concrete structure 11 is surely kept in a wet state. The electrical contact with the verification surface 11d of the concrete structure 11 becomes good. However, the collation electrode 31 should just be able to contact the surface in the collation surface 11d of the concrete structure 11, and is not limited to embodiment mentioned above.

  In this embodiment, the verification electrode 31 is formed in a substantially cylindrical shape as shown in FIG. 2A. However, if the verification electrode 31 is formed so as to be in contact with the surface in the verification surface 11d, its shape Is not particularly limited, and may be formed in other shapes such as a substantially prismatic shape. Further, in the present embodiment, as shown in FIG. 1, the reference electrode 31 has a contact area (diameter thereof) whose size substantially corresponds to the width of the steel material 11 b embedded in the concrete structure 11 or of the steel material 11 b. It is formed to have a size slightly larger than the width. If the collation electrode 31 can contact the surface in the collation surface 11d, the size of the contact area is not particularly limited. However, in order to measure the potential of each steel material 11b, the concrete structure 11 It is preferable that the size does not extend over a plurality of embedded steel materials 11b.

<Potential difference measuring device>
The potential difference measuring device 4 measures a potential difference between the reference contact portion 2 and each of the plurality of verification electrodes 31. As shown in FIG. 1, the potential difference measuring device 4 has two terminals on the plus side and the minus side. One or the other terminal of the potential difference measuring device 4 is electrically connected to the reference contact portion 2 via a conducting wire 6 such as a lead wire. The other or one terminal of the potential difference measuring device 4 is electrically connected to each of the plurality of verification electrodes 31 via a conducting wire 6 such as a lead wire. As the potentiometer 4, a potentiometer used in a known natural potential measuring method can be used. However, the potentiometer is not particularly limited to such a potentiometer, and any device that can measure a potential difference between two points. Anything can be used.

<Information processing device>
The steel material potential measuring device 1 of the present embodiment further includes an information processing device 5 as shown in FIG. The information processing device 5 is connected to the potential difference measuring device 4 so as to be capable of information communication, receives information such as a potential difference from the potential difference measuring device 4, processes the received information, and displays the received information and / or the processed information. It is configured to display. In the present embodiment, the information processing device 5 includes a processing device main body 51 for processing information and a display device 52 for displaying information. As schematically shown in FIGS. 5A and 5B, the information processing device 5 displays a potential difference distribution that associates the obtained potential difference with the position where the potential difference is obtained on the display device 52. The three-dimensional or three-dimensional display can be performed, and the distribution of the corrosion state of the steel material 11b after determining the corrosion state by comparing the obtained potential difference with the threshold value can be displayed two-dimensionally or three-dimensionally. In FIG. 5A and FIG. 5B, the region a surrounded by the fine grid lines corresponds to the region of the surface of the concrete structure 11 with which each of the plurality of reference electrodes 31 is in contact with the thick grid. A region A surrounded by a line corresponds to the region of the verification surface 11d. And the area | region shown with the oblique line in the figure has shown the area | region where the electric potential difference lower than a threshold value (large absolute value) was obtained. The information processing device 5 is not particularly limited, and for example, an arithmetic processing device such as a CPU, a storage device such as a hard disk, a communication device such as a network interface, an input device such as a keyboard / mouse, a display such as a liquid crystal display A known computing device such as a personal computer provided with the device inside or outside can be used.

  The information processing device 5 is configured to calibrate the measured potential difference for each of the plurality of verification electrodes 31 in order to correct a shift in electrode potential unique to the verification electrode 31. More specifically, the information processing device 5 calibrates the potential difference measured by the potential difference measuring device 4 for each of the plurality of verification electrodes 31 using a calibration formula obtained in advance for each of the plurality of verification electrodes 31. It is configured as follows. The calibration formula is such that, for example, a plurality of verification electrodes 31 are brought into contact with each of two standard surfaces having different known potentials, and two potentials for each standard surface are detected by the potential difference measuring device 4 for each of the verification electrodes 31. Can be obtained as a linear form from the two measured potentials and the two known potentials. The potential difference measured for each of the plurality of verification electrodes 31 is calibrated by the information processing device 5, whereby the potential difference can be obtained with high accuracy for each of the plurality of verification electrodes 31. Therefore, the degree of corrosion of the steel material can be accurately determined, and the distribution of the corrosion state can be determined with higher accuracy. The calibration formula only needs to be able to correct the deviation of the electrode potential unique to the verification electrode 31, and may be obtained by a method other than the above-described method, for example, using one or three or more standard surfaces.

  Further, the information processing device 5 is configured to obtain a statistical value of a potential difference for each of the plurality of verification electrodes 31 for each of the plurality of verification surfaces 11d. Here, the statistical value of the potential difference for each verification surface 11d is an average value of a plurality of potential differences (measured potential difference and / or calibrated potential difference) obtained within the same verification surface 11d, and the deviation for each verification electrode 31. Value, standard deviation value, center value, maximum value, minimum value, and other values calculated by other statistical value calculation methods. For example, by obtaining the average value of the potential differences for each of the plurality of collation surfaces 11d, the potential distribution can be measured in the collation surface 11d unit of the large region, not the potential distribution of the small region unit corresponding to each collation electrode 31. . Accordingly, the corrosion state of the steel material 11b in the concrete structure 11 can be determined in units of the collation surface 11d in a large region, and as a result, the visibility of the distribution when the corrosion state distribution is displayed two-dimensionally or three-dimensionally is improved. The corrosion state distribution of the steel material 11b can be roughly grasped. Furthermore, referring to FIG. 4 (a) schematically showing the potential difference distribution for each region corresponding to the verification electrode 31, and FIG. 4 (b) schematically showing the average potential difference distribution for each verification surface 11d. As can be seen, for example, as shown in FIG. 4 (a), even if there is only one region that may be determined to be a singular value in the approximate center of FIG. 4 (a), FIG. ), The singular value can be canceled by calculating the average for each reference surface 11d, so that the corrosion state of the steel material can be determined more accurately. Further, for example, by obtaining the deviation value for each of the verification electrodes 31 or the standard deviation value of the potential difference for each of the plurality of verification surfaces 11d, the corrosion state variation of the steel material 11b in the verification surface 11d can be evaluated. The distribution of the difference in the degree of variation in the corrosion state for each surface 11d can be determined.

  Further, the information processing device 5 may be configured to obtain an average value of potential differences measured twice or three times or more at substantially the same contact location for each of the plurality of verification electrodes 31. By configuring the information processing apparatus 5 in this way, even if an abnormal value due to electronic circuit noise or the like is accidentally generated in any of the plurality of verification electrodes 31, the abnormal value can be canceled. Therefore, it is possible to maintain the measurement accuracy and correctly grasp the potential distribution of the measurement target. Here, in the potential measurement using the conventional spot type single electrode, the measurement accuracy is maintained virtually by measuring the same portion a plurality of times in the same manner as the steel material potential measuring device 1 of the present embodiment. However, in reality, more time is spent on measurement, and it is difficult to maintain measurement accuracy by performing multiple measurements. In addition, in the conventional potential measurement using a rotary electrode, a relatively quick measurement is possible, so that multiple measurements at the same location are allowed, but in reality, the rotational position of the electrode is the same every measurement time. Since it is impossible to average a plurality of potential differences obtained from the same location unless it corresponds to the measurement location, it is difficult to measure multiple times and maintain measurement accuracy. However, according to the steel material potential measuring apparatus 1 of the present embodiment, the potentials of a plurality of regions of the steel material 11b can be efficiently measured. Therefore, even if a plurality of measurements are performed, the measurement is performed in comparison with the conventional method. Sufficient speeding-up can be achieved and measurement accuracy can be maintained, and both speeding-up of measurement and maintenance of accuracy can be achieved.

  Furthermore, the information processing device 5 obtains a potential difference deviation for each of the plurality of collation electrodes 31 every two or three or more measurement times on the same collation surface 11d, and the deviations of the respective measurement times are mutually determined. The difference is compared with a predetermined threshold value, and it is determined whether or not the potential difference for each of the plurality of verification electrodes 31 is an abnormal value (a value that does not indicate the original potential difference due to electronic circuit noise or the like). It may be configured as follows. More specifically, according to the information processing apparatus 5, first, with respect to the same verification surface 11d, the deviation of the potential difference for each of the plurality of verification electrodes 31 obtained by the first measurement and the second time A difference from the deviation of the potential difference for each of the plurality of verification electrodes 31 obtained by the measurement is obtained. Here, the deviation of the potential difference is a difference between the average of the plurality of potential differences obtained by the plurality of verification electrodes 31 and the potential difference obtained by each of the plurality of verification electrodes 31 in one measurement. Next, the difference in deviation for each verification electrode 31 is compared with a predetermined threshold (for example, 10 mV). If the difference in deviation is equal to or smaller than the predetermined threshold, it is determined that the potential difference is not an abnormal value. Is greater than a predetermined threshold value, it is determined that the potential difference is an abnormal value. Therefore, according to the steel material potential measuring apparatus 1 of the present embodiment, the abnormal value can be grasped more reliably, and the reliability of the measurement result can be improved. If it is determined that the potential difference is an abnormal value, the potential difference is remeasured for the collation surface 11d determined to have an abnormal value, or the abnormal value is used to determine the reliability of the measurement result. Reference value. Instead of obtaining the difference between the potential difference obtained by the first measurement and the potential difference obtained by the second measurement, the difference obtained by the first measurement was obtained by the second measurement. By obtaining the difference from the deviation, the verification electrodes 31 can be evaluated relative to each other.

<Steel material potential measurement method>
Next, a steel material potential measuring method of the present embodiment using the above-described steel material potential measuring device 1 will be described with reference to the flowchart shown in FIG. 3 and the schematic diagrams shown in FIGS. 4 and 5.

  As shown in FIG. 3, the steel material potential measurement method of the present embodiment includes steps S1 to S4. First, in step S1, the reference contact portion 2 is brought into contact with the reference position. In this embodiment, as shown in FIG. 4A, the reference electrode 22 that is the reference contact portion 2 is brought into contact with the reference surface 11c that is the reference position. More specifically, the wet pad of the reference electrode 22 in a wet state is brought into contact with the reference surface 11c of the concrete structure 11, and the reference electrode 22 is held at the position of the reference surface 11c. As the reference surface 11c with which the reference electrode 22 is brought into contact, a location where there is no or little corrosion of the steel material 11b immediately below is selected by a preliminary investigation or the like. In addition, for example, when a location where the corrosion of the steel material 11b directly below is selected as the reference surface 11c with which the reference electrode 22 is brought into contact, a region having a natural potential higher than the natural potential on the reference surface 11c was found in a later step. In that case, the region may be newly set as a reference surface 11c as a portion with less corrosion or no corrosion. Moreover, in the example shown by Fig.4 (a), although the reference electrode 22 is made to contact the reference surface 11c, you may make the reference terminal 21 contact the steel material 11b.

  Next, in step S2, the verification electrode unit 3 is arranged on the verification surface 11d of the concrete structure 11, thereby bringing the plurality of verification electrodes 31 into contact with the surface in the verification surface 11d (FIG. 4A). More specifically, like the reference electrode 22, the wet pad of the verification electrode 31 is brought into contact with the surface in the verification surface 11d of the concrete structure 11, and the verification electrode 31 is held at the surface position. To do. In the present embodiment, as shown in FIG. 4A, the verification electrode unit 3 covers the plurality of steel materials 11b, and the verification surface 11d is sized to straddle the plurality of steel materials 11b. . In addition, process S1 and process S2 may be reverse order.

  After the arrangement of the reference contact portion 2 and the verification electrode unit 3 is completed in steps S1 and S2, in step S3, the potential difference measuring device 4 (see FIG. 1) and the reference electrode 22 as the reference contact portion 2 and the plurality of reference electrodes 22 The potential difference between each of the reference electrodes 31 is measured. Thereby, the difference (relative potential) between the natural potential of the steel material 11b on the reference surface 11c (reference potential) and the natural potential of the steel material 11b on each surface in the reference surface 11d is measured. At this time, when the verification electrode unit 3 is arranged on the verification surface 11d, the plurality of verification electrodes 31 arranged in two dimensions are simultaneously brought into contact with the plurality of surfaces in the verification surface 11d. The relative potential of the region can be measured simultaneously. Therefore, according to the steel material potential measurement method of the present embodiment, the potentials of a plurality of regions of the steel material 11b can be efficiently measured as compared with the conventional method. Furthermore, the corrosion state of the several area | region of the steel material 11b can be determined simultaneously, and the corrosion state of the steel material 11b in the concrete structure 11 with which the steel material 11b was embed | buried can be determined efficiently compared with the conventional method. If the natural potential on each surface in the collation surface 11d is lower than the reference potential by a predetermined threshold or more, it is located in the vicinity of the cover thickness direction of each surface in the collation surface 11d (in the vicinity of almost directly below each surface). ) It is determined that a corrosion site exists in the steel material 11b. On the other hand, when the natural potential on each surface in the verification surface 11d is substantially the same as the reference potential, or the difference is within a predetermined threshold range, the vicinity of each surface in contact with the plurality of verification electrodes 31 It is determined that no corrosion site exists in the steel material 11b.

  After step S3, in step S4, it is determined whether there is another surface to be measured. If there is another surface to be measured (Yes in step S4), the verification electrode unit 3 is moved along the surface of the concrete structure 11, and the steps S2 and S3 are repeated (FIGS. 4B to 4B). FIG. 4 (c)). That is, the reference electrode unit 3 is moved along the surface of the concrete structure 11 and sequentially disposed on the plurality of reference surfaces 11d, and the reference electrode 22 that is the reference contact portion 2 is provided for each of the plurality of reference surfaces 11d. A potential difference between each of the plurality of verification electrodes 31 is measured. Then, step S2 and step S3 are repeated until there is no other surface to be measured (No in step S4). Here, in the steel material potential measuring device 1 of the present embodiment, as shown in FIG. 2B, the verification electrode holding portion 32 of the verification electrode unit 3 is formed in a substantially rectangular shape, and the verification electrode 31 is used as the verification electrode. The holding parts 32 are arranged in a matrix at substantially equal intervals, and the distance between each of the first side 33 and the second side 34 of the verification electrode holding part 32 and the verification electrode 31 is an approximate distance between the verification electrodes 31. It is arranged to be half. Therefore, as shown in FIG. 4B, the reference electrode unit 3 is moved along the first direction X and / or the second direction Y, and the first direction X and / or the second direction is moved. Each of the plurality of verification electrodes 31 can be brought into contact with the surface of the concrete structure 11 at substantially equal intervals simply by sequentially arranging them on the plurality of verification surfaces 11d adjacent by Y. Therefore, it becomes easy to measure the distribution of the potential of the steel material 11b at equal intervals, and the distribution of the corrosion state of the steel material 11b in the concrete structure 11 can be determined efficiently and accurately in a short time. In particular, in order to obtain good electrical contact between the reference electrode 22 and the reference electrode 31 and the surface of the concrete structure 11 before the steps S1 and S2, water is sprayed on the surface of the concrete structure 11. Even so, according to the corrosion potential measurement method of the present embodiment, the potential distribution of the steel material 11b can be measured efficiently, and the corrosion state of the steel material 11b can be determined efficiently, so the wet state of the surface changes. The measurement can be completed before, and the corrosion state can be determined by measuring the potential of the steel material 11b more accurately than in the conventional method.

  As shown in FIG. 3, the steel material potential measuring method of the present embodiment may further include steps S5 and S6 performed subsequent to steps S1 to S4. In step S <b> 5, the measured potential difference is calibrated for each of the plurality of verification electrodes 31 in order to correct a shift in electrode potential unique to the verification electrode 31. More specifically, the potential difference measured by the potential difference measuring device 4 for each of the plurality of verification electrodes 31 is calibrated by the information processing device 5 using a calibration formula obtained in advance for each of the plurality of verification electrodes 31. . By calibrating the potential difference measured for each of the plurality of verification electrodes 31 by the information processing device 5, the potential of the steel material 11b can be accurately measured, and the degree of corrosion of the steel material 11b can be accurately determined. it can.

  In step S6, a statistical value of a potential difference for each of the plurality of verification electrodes 31 is obtained for each of the plurality of verification surfaces 11d. As described above, as the statistical value to be obtained, as described above, an average value of a plurality of potential differences (measured potential difference and / or calibrated potential difference) obtained in the same verification surface 11d, a deviation value for each verification electrode 31, a standard deviation It is a value calculated by a value, center value, maximum value, minimum value, and other statistical value calculation methods. For example, by determining the average value of the potential differences for each of the plurality of verification surfaces 11d, it is possible to determine the corrosion state not in the small area unit corresponding to each verification electrode 31 but in the large area verification surface 11d unit. Therefore, the corrosion state distribution of the steel material 11b in the concrete structure 11 can be roughly grasped. Furthermore, even if there is a region that may be determined to be a singular value in the region corresponding to the collation electrode 31, the singular value can be canceled by obtaining an average for each collation surface 11d. It is possible to more accurately determine the corrosion state of the steel material (see FIGS. 5A and 5B).

  Further, in the steel material potential measuring method of the present embodiment, the step 3 is further repeated for the same reference surface 11d, and the potential difference measured two or more times at the same contact location for each of the plurality of reference electrodes 31. The process of calculating | requiring the average value of may be included. Even if an abnormal value due to electronic circuit noise or the like is accidentally generated in any of the plurality of verification electrodes 31 by obtaining an average value of two or three or more potential differences for each of the plurality of verification electrodes 31. Since the accidental abnormal value can be canceled, the measurement accuracy can be maintained and the potential distribution of the measurement target can be correctly grasped. According to the steel material potential measurement method of the present embodiment, as described above, the potential of a plurality of regions of the steel material 11b can be efficiently measured, so even if a plurality of measurements are performed, measurement is performed as compared with the conventional method. Can be sufficiently speeded up and the measurement accuracy can be maintained, and both the speeding up of the measurement and the maintenance of the accuracy can be achieved.

  Further, the steel material potential measurement method of the present embodiment further repeats step 3 on the same verification surface 11d, and the plurality of verification electrodes 31 are measured every two or three or more measurement times on the same verification surface 11d. A step of obtaining a potential difference deviation for each of them, comparing each difference of measurement deviations with a predetermined threshold value, and determining whether or not the potential difference for each of the plurality of verification electrodes 31 is an abnormal value. May be included. More specifically, in this step, first, with respect to the same verification surface 11d, the potential difference deviation for each of the plurality of verification electrodes 31 obtained by the first measurement and the second measurement are obtained. Further, the difference from the potential difference deviation for each of the plurality of verification electrodes 31 is obtained. Next, the difference in deviation for each verification electrode 31 is compared with a predetermined threshold value (for example, 10 mV), and if the potential difference deviation is equal to or smaller than the predetermined threshold value, it is determined that the potential difference is not an abnormal value. Is greater than a predetermined threshold value, it is determined that the potential difference is an abnormal value. Therefore, according to the steel material potential measurement method of the present embodiment, the abnormal value can be grasped more reliably, and the reliability of the measurement result can be improved. If it is determined that the potential difference is an abnormal value, the potential difference is remeasured for the reference surface 11d determined to have an abnormal value, or the abnormal value is a reference for determining the reliability of the measurement result. Value.

DESCRIPTION OF SYMBOLS 1 Steel material potential measuring apparatus 2 Reference contact part 21 Reference terminal 22 Reference electrode 3 Reference electrode unit 31 Reference electrode 32 Reference electrode holding part 33 1st edge | side 34 2nd edge | side 4 Potential difference measuring device 5 Information processing apparatus 51 Processing apparatus main body 52 Display device 6 Conductor 11 Concrete structure 11a Concrete 11b Steel (rebar)
11c Reference surface 11d Reference surface X First direction Y Second direction

Claims (10)

A steel material potential measuring method for measuring the potential of a steel material embedded in a concrete structure using a steel material potential measuring device,
The steel material potential measuring device,
A reference contact portion that contacts the reference position;
A plurality of reference electrodes in contact with the surface of the concrete structure, and a reference electrode unit having a reference electrode holding part for holding the plurality of reference electrodes;
The reference contact portion and each of the plurality of verification electrodes are connected, and a potential difference measuring device that measures a potential difference between the reference contact portion and each of the plurality of verification electrodes, and
Each of the plurality of verification electrodes is two-dimensionally arranged on the verification electrode holding portion at a distance from each other in a plane including a first direction and a second direction orthogonal to each other.
The steel material potential measuring method,
Bringing the reference contact portion into contact with the reference position;
Placing the plurality of reference electrodes in contact with the surface in the reference surface by placing the reference electrode unit on the reference surface of the concrete structure;
A step of measuring a potential difference between the reference contact portion and each of the plurality of verification electrodes by the potential difference measuring device;
The reference electrode unit is moved along the surface of the concrete structure and sequentially arranged on a plurality of reference surfaces, and for each of the reference surfaces, the reference contact portion and each of the plurality of reference electrodes A method for measuring the potential of a steel material, characterized by measuring a potential difference between the two. The steel material potential measuring method according to claim 1, further comprising a step of calibrating the measured potential difference for each of the plurality of verification electrodes in order to correct a shift in electrode potential unique to the verification electrode. The steel material potential measurement method according to claim 1, further comprising a step of obtaining a statistical value of the potential difference for each of the plurality of verification electrodes for each of the plurality of verification surfaces. The arrangement interval of the plurality of verification electrodes is smaller than the distance between two steel materials that are embedded in the concrete structure so as to be spaced apart from each other, and the interval between the verification electrodes that are arranged the most apart from each other is in the concrete structure. The steel material potential measuring method according to any one of claims 1 to 3, wherein the steel material potential measuring method is larger than a distance between two steel materials embedded separately. The reference electrode holding portion is formed in a substantially rectangular shape having a pair of first sides extending along the first direction and a pair of second sides extending along the second direction;
The plurality of verification electrodes are arranged in a substantially equidistant matrix along the first direction and the second direction on the verification electrode holding unit,
Both the distance between the first side and the reference electrode closest to the first side and the distance between the second side and the reference electrode closest to the second side are the first side. 5. The steel material potential measurement method according to claim 1, wherein the steel material potential measurement method is approximately half of an arrangement interval of the reference electrodes in the first direction and the second direction. A steel material potential measuring device used to measure the potential of a steel material embedded in a concrete structure,
A reference contact portion that contacts the reference position;
A plurality of reference electrodes in contact with the surface of the concrete structure, and a reference electrode unit having a reference electrode holding part for holding the plurality of reference electrodes;
The reference contact portion and each of the plurality of verification electrodes are connected, and a potential difference measuring device that measures a potential difference between the reference contact portion and each of the plurality of verification electrodes, and
Each of the plurality of verification electrodes is two-dimensionally arranged at a distance from each other in a plane including a first direction and a second direction orthogonal to each other on the verification electrode holding portion. Steel potential measuring device. The arrangement interval of the plurality of verification electrodes is smaller than the distance between two steel materials that are embedded in the concrete structure so as to be spaced apart from each other, and the interval between the verification electrodes that are arranged the most apart from each other is in the concrete structure. The steel material potential measuring device according to claim 6, wherein the steel material potential measuring device is larger than a distance between two steel materials embedded in a separated manner. The reference electrode holding portion is formed in a substantially rectangular shape having a pair of first sides extending along the first direction and a pair of second sides extending along the second direction;
The plurality of verification electrodes are arranged in a substantially equidistant matrix along the first direction and the second direction on the verification electrode holding unit,
Both the distance between the first side and the reference electrode closest to the first side and the distance between the second side and the reference electrode closest to the second side are the first side. The steel material potential measuring device according to claim 6 or 7, wherein the steel material potential measuring device is approximately half of the arrangement interval of the reference electrodes in the direction of and the second direction. The steel material potential measuring device includes an information processing device,
7. The information processing apparatus is configured to calibrate a measured potential difference for each of the plurality of verification electrodes in order to correct a shift in electrode potential unique to the verification electrode. The steel material electric potential measuring apparatus of any one of -8. The steel material potential measuring device includes an information processing device,
The information processing apparatus is configured to obtain a statistical value of the potential difference for each of the plurality of verification electrodes for each of the plurality of verification surfaces. The steel material potential measuring device according to 1.

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