JP2017179467A - Electrical protection structure for reinforced concrete structure and method for measuring effect of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method that can measure, without an operator's high-place hazardous work even if the current measurement site locates in a high place, in order to easily specify the location of a corrosion generating place and to check corrosion protection or corrosion inhibition effect in an electrical protection structure for a reinforced concrete structure.SOLUTION: At least a part of a conductive material for conducting a plurality of anode materials 3 and an internal rebar 2 is exposed on an outer surface of a concrete structure 1 to measure a current value of the exposed part in the electrical protection structure for the reinforced concrete structure. The electrical protection structure for the reinforced concrete structure suppresses corrosion of the internal rebar by the potential difference generated between the anode materials 3 and the internal rebar 2 with the anode materials 3 buried in the reinforced concrete structure 1 and the internal rebar 2 connected by a conductive material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrical corrosion protection structure in a reinforced concrete structure such as an elevated road or a reinforced concrete floor slab of a bridge, and a method for measuring the effect of the electrical corrosion protection structure.

  In reinforced concrete structures such as reinforced concrete slabs that form elevated roads and bridges, internal reinforcement due to the neutralization of concrete, the salt content of concrete, the effects of salt from the outside and antifreezing materials (salt damage) May corrode and lead to deterioration of the reinforced concrete structure.

  Conventionally, as a countermeasure for the corrosion of reinforcing bars, there are known an electric corrosion prevention method for preventing corrosion of reinforcing bars by supplying electric current to the reinforcing bars or an electric corrosion inhibiting method for suppressing corrosion of reinforcing bars. Depending on the supply method, it is roughly divided into an external power supply method and a galvanic anode method. (Hereinafter, in this specification, it is referred to as “electric corrosion prevention” including the above “electric corrosion inhibition”)

  In the external power supply system, an insoluble anode made of titanium or the like is installed on the concrete surface or inside the concrete, and a direct current power supply device is connected between the insoluble anode and the reinforcing bar forming the cathode, and current is supplied to the reinforcing bar from the insoluble anode. However, since the amount of current can be adjusted and the long-term anticorrosion property is excellent, it is positioned as an electric anticorrosion and has been conventionally used in many anticorrosion structures for reinforced concrete slabs.

  In the galvanic anode method, a galvanic anode made of zinc, aluminum, etc., which has a lower oxidation-reduction potential than that of a reinforcing bar, is installed on the concrete surface or inside the concrete, and a current is supplied to the reinforcing bar using the potential difference between this galvanic anode and the reinforcing bar. Since the amount of current generated is smaller than that of the external power supply system, it is positioned as an electrical corrosion inhibitor. However, because it can be expected to have a sufficient corrosion-inhibiting effect, and no external power supply is required, and the introduction and maintenance costs are low, the application of this type of corrosion-inhibiting structure to reinforced concrete slabs is drawing attention. .

  In addition, this type of cathodic protection structure is classified into a planar anode method, a linear anode method, and a dotted anode method depending on the arrangement of the anode with respect to the reinforced concrete structure.

  In the planar anode method, a sheet-like or net-like anode material is laid on the surface of a reinforced concrete structure. In the linear anode method, a plurality of grooves are formed on the concrete surface, and the grooves are linear. The anode material is embedded.

  In addition, in the point anode method, a plurality of holes are provided in concrete according to the amount of reinforcing bars, and after inserting the anode material there, the holes are backfilled with cement-based mortar and the anode is installed in the concrete. (For example, refer to Patent Document 1).

  In order to confirm the effect of such an anticorrosion method, conventionally, a reference electrode is embedded in the reinforced concrete structure separately from the anode during the anticorrosion work, and this and the reinforced concrete structure are reinforced. A method is known in which an electrical circuit for confirming the effect of electrical connection is formed, an ammeter is provided in the electrical circuit, and a potential difference between the reference electrode and the reinforcing bar is measured (for example, Patent Document 2). , 3).

Japanese translation of PCT publication No. 8-511581 Japanese Examined Patent Publication No. 4-35032 JP2013-224456A

  In the electric corrosion prevention structure in the conventional reinforced concrete structure described above and the effect measurement method of the electric corrosion prevention structure, a voltmeter is incorporated in a circuit (hereinafter referred to as an effect confirmation circuit) constituted by a reinforcing bar, a measurement terminal, and a verification electrode, Measure the natural potential of the reinforcing bar near the reference electrode with a voltmeter when supplying electricity for anticorrosion and when not supplying it, and the difference between when electricity is supplied and when it is not supplied There is a method of grasping the anticorrosion (corrosion suppression) effect by (recovery amount). In this case, since a part of the circuit is opened and a voltmeter is installed, and the voltage is measured and recorded at all times or at regular intervals, the cost increases.

  In this case, there is a problem that only the situation in the vicinity of the verification electrode can be grasped.Therefore, in order to grasp the situation of many points, it is necessary to install a large number of verification electrodes, and a large number of effect confirmation circuits are required. Many wiring materials are required, which further increases the cost.

  Furthermore, in the effect confirmation circuit using these verification electrodes, the conductor from the verification electrode or the reinforcing bar to the voltmeter is embedded in the surface layer part of the reinforced concrete structure, so the measurer needs to approach the voltmeter installation position. Since these positions are usually high places, there is a problem that the work may be dangerous. In order to avoid this danger, the effect confirmation circuit may be measured on a safe ground, but for that purpose, the length of the wiring piping becomes longer, which also leads to an increase in cost.

  In other conventional reinforced concrete structures, the electrical corrosion prevention structure and the method of measuring the effect of the electrical corrosion prevention structure include a current from the entire sacrificial anode to the entire rebar in the case of the galvanic anode method, and an external power supply method. Has a method to estimate the effect by measuring the current from the DC power supply to the entire rebar with an ammeter built into the effect confirmation circuit and dividing this by the target area to estimate the amount of current flowing through each part. .

  In this case, since the estimated value can only be obtained as an average value that flows to the target part, if the deterioration state varies depending on the location, or if local deterioration is progressing, the consumption state of the anode is grasped. I can't.

  Furthermore, in a general concrete buried type galvanic anode material, the galvanic anode material-wiring-reinforcing bars are all buried in the concrete, and the corrosion prevention (corrosion suppression) effect itself is not measured. There is.

  In view of such a conventional problem, the present invention can accurately provide a potential difference for electrical protection between each anode material and a reinforcing bar approaching it in electrical protection of a reinforced concrete structure. In addition, potential measurement or current measurement for confirming the electrical anticorrosive effect between each anode material and the reinforcing bar should be carried out at a low cost between each individual anode material and the reinforcing bar corresponding to this. In addition, it is possible to easily identify the location where corrosion occurs, and even when the current measurement site is high, the electrical corrosion protection structure in the reinforced concrete structure can be measured without dangerous work at the operator's height The object is to provide a method for measuring the effect of the electrically anticorrosive structure.

  A first feature of the present invention for solving the conventional problems as described above includes a plurality of anode materials embedded in a reinforced concrete structure, and a conductive material connecting the anode materials and internal reinforcing bars, and the anode material At least a part of the conductive material for electrically connecting the anode material and the internal rebar in the electrically anticorrosive structure in the reinforced concrete structure in which corrosion of the internal rebar is suppressed by a potential difference generated between the internal rebar and the internal rebar Is an electrically anticorrosive structure in a reinforced concrete structure, characterized in that is exposed to the outer surface of the concrete structure.

  The second feature of the present invention is that, in addition to the first feature, the exposed conductive material on the outer surface of the reinforced concrete structure is a non-corrosive conductive material.

  According to a third feature of the present invention, in addition to the first or second feature, the individual conductive materials are electrically connected to each anode material, and at least a part of each of the individual conductive materials is the reinforced concrete structure. Being exposed to the surface.

  A fourth feature of the present invention includes a plurality of anode materials embedded in a reinforced concrete structure, a conductive material connecting the anode materials and internal reinforcing bars, and is generated between the anode material and the internal reinforcing bars. A method for measuring the effect of an electrical protection structure in which corrosion of the internal rebar is suppressed by a potential difference, wherein at least a part of a conductive material that conducts the anode material and the internal rebar is exposed to the surface of the reinforced concrete structure. In other words, the current of the exposed portion of the conductive material from the reinforced concrete structure is measured using an overhead wire current measuring device.

  A fifth feature of the present invention is that, in addition to the fourth feature, a non-corrosive conductive material is used as the conductive material exposed on the surface of the reinforced concrete structure.

  According to a sixth aspect of the present invention, in addition to the fourth or fifth aspect, the individual conductive materials are electrically connected for each anode material, and at least a part of each individual conductive material is connected to the reinforced concrete structure. It is to be exposed on the surface.

  As described in the first feature, the present invention includes a plurality of anode materials embedded in a reinforced concrete structure, and a conductive material connecting the anode materials and internal reinforcing bars, and the anode material and the internal reinforcing bars In the electrically anticorrosive structure in the reinforced concrete structure in which the corrosion of the internal rebar is suppressed by the potential difference generated in the outer surface of the concrete structure, at least part of the conductive material that conducts the anode material and the internal rebar Thus, the value of the current flowing in the portion exposed from the reinforced concrete structure of the conductive material can be measured using the overhead wire current measuring instrument.

  Therefore, there is no need to install a reference electrode or install a voltmeter permanently in the circuit between the reference electrode and the reinforcing bar, and workers can measure overhead current from the ground even at high places such as under the concrete floor slab of an elevated road. Since the measurement can be performed by bringing the instrument close to the measurement position, the work at a high place is unnecessary and the safety of the work is high.

  As described in the second and fifth features, the present invention provides a circuit for confirming the anticorrosion or corrosion inhibition effect by using the conductive material exposed on the outer surface of the reinforced concrete structure as a non-corrosive conductive material. Durability is maintained even if the conductive material to be constructed is not embedded in the surface of the reinforced concrete structure, and it can be adapted for long-term effect confirmation.

  In the present invention, as in the third and sixth features, the individual conductive materials are electrically connected to each anode material, and at least a part of each individual conductive material is exposed on the surface of the reinforced concrete structure. As a result, the anticorrosion or corrosion inhibition effect at a position near the anode material of the internal rebar can be confirmed, so that it is possible to detect a position where the effect is not recognized or low. Therefore, it is possible to determine the degree of consumption of each anode and to estimate the life.

  As in the fourth feature, the present invention includes a plurality of anode materials embedded in a reinforced concrete structure, a conductive material connecting the anode materials and the internal reinforcing bars, and the anode material and the internal reinforcing bars. A method for measuring the effect of the corrosion prevention structure in which corrosion of the internal rebar is suppressed by a potential difference generated in the reinforced concrete structure, wherein at least a part of the conductive material for electrically connecting the anode material and the internal rebar is provided in the reinforced concrete structure. It is exposed to the surface, and the current of the exposed portion from the reinforced concrete structure of the conductive material is measured using an overhead wire current measuring device, so that the collation electrode can be installed and the collation electrode as in the past. There is no need to install an ammeter permanently in the circuit between the steel bar and the reinforcing bar. Since it is possible to measure by approaching to, it becomes aerial is high work safety becomes unnecessary.

It is sectional drawing which shows an example which implemented the cathodic protection structure of the reinforced concrete floor slab which concerns on this invention to the galvanostatic anode system which uses a point-like anode. It is a partial bottom view same as the above. It is a perspective view which shows the electric current measurement state for the effect confirmation in an electric corrosion prevention structure same as the above. It is explanatory drawing which shows the other example of the electric current measurement state for the effect confirmation in an electric corrosion prevention structure same as the above. It is explanatory drawing which shows the modification same as the above. It is explanatory drawing which shows an example which implemented the cathodic protection structure of the reinforced concrete floor slab which concerns on this invention to the galvanic anode system which uses a linear anode. It is sectional drawing which shows an example which implemented the cathodic protection structure of the reinforced concrete floor slab which concerns on this invention to the external power supply system which uses a point-like anode.

  Next, an embodiment of the electric corrosion prevention structure and the effect measurement method of the electric corrosion prevention structure in the reinforced concrete structure according to the present invention will be described based on the embodiments shown in the drawings.

  FIG. 1 and FIG. 2 show an example of a grain electrode anode-type electric corrosion prevention structure. In the figure, reference numeral 1 denotes a reinforced concrete structure such as a reinforced concrete floor slab, 2 denotes an internal reinforcing bar of the reinforced concrete structure 1, and 3 denotes an anode material.

  The anode material 3 is accommodated in the anode installation holes 4 formed at regular intervals along the internal rebar 2 on the surface of the reinforced concrete structure 1, and is embedded in the anode installation holes 4 by a filler 5 made of an electrolyte. ing.

  Each anode material 3 is electrically connected to one end side of a lead wire 6 which is an individual conductive material. A part of the lead wire 6 is exposed on the surface of the reinforced concrete structure 1, and the other end is electrically connected to an anode-rebar conductive material 7 that is electrically connected to the internal rebar 2. The anode-reinforcing bar conductive material 7 is inserted into a groove 8 formed on the surface of the reinforced concrete structure 1, and is buried with a filler 9 such as mortar.

  The lead wire 6 is arranged so that at least a part of the exposed portion from the reinforced concrete structure 1 is raised from the surface of the reinforced concrete structure 1 as shown in the figure, and is placed in an opening-and-closing ring-shaped sensor portion of a clamp meter described later. Arrange it so that it can enter. The lead wire 6 may be a rust-proof coated electric wire, and is made of a conductive metal material whose outer peripheral surface is coated with a corrosion-resistant conductive material such as carbon or a bare wire made of a non-corrosive conductive material such as titanium. May be used.

  In the electrical protection structure constructed in this way, a current flows in the concrete due to the potential difference between the anode material 3 and the reinforcing bar 1 to prevent the flow of corrosion current around the reinforcing bar, thereby preventing or suppressing the corrosion of the reinforcing bar. The

  The above-mentioned anticorrosion effect of the electric anticorrosion structure is confirmed by knowing whether or not an electric current is flowing in the concrete between the internal rebar 2 and the anode material 3 in the reinforced concrete structure 1. It can be measured by measuring the value of the current flowing through the lead wire 6 of the anode material 3.

  Whether or not a current is flowing in the lead wire 6 or how much current is flowing can be measured by an overhead wire current measuring instrument 10 called a clamp meter. The overhead wire current measuring device 10 measures the current value flowing through the overhead wire by using the semiconductor Hall effect by penetrating the overhead wire into the ring-shaped sensor portion 11 as shown in FIG. The ring shape has a structure that can be opened and closed by a river operation, and by using this, the current value flowing through the lead wire 6 is measured, whereby the anode material 3 and the internal rebar 2 corresponding to the lead wire 6 are measured. You can know the current value in the concrete between.

  In addition to using the above-mentioned overhead wire current measuring device 10, when using a bare wire of a non-corrosive conductive material such as titanium as a lead wire, the electrical resistance R (Ω / m) of the same material is measured prior to use. In addition, the voltage V (V) applied to an appropriate interval of the same material exposed on the concrete surface is measured with a DC voltmeter, and the anticorrosion current I can be obtained from I = V / (R × L).

  That is, as shown in FIG. 4, a measuring apparatus using current measuring electrodes 12 and 12 made of two conductive rods with an appropriate distance between the tips and incorporating a voltmeter 13 between the electrodes. The current value flowing through the lead wire 6 can also be easily measured by using the electrodes 12 and 12 in contact with the lead wire 6 and measuring the voltage between the electrodes at that time.

  Further, as shown in FIG. 5, the two current measuring electrodes 12 and 12 of the measuring device are attached to the tip of a support rod 14 which can be expanded and contracted, and two current measuring electrodes are provided at the proximal portion of the support rod 14. If a voltmeter 13 that can measure the voltage between 12 and 12 is installed, it is possible to remotely measure a certain high place or a place where proximity is impossible.

  By measuring the current value for each anode material 3 in this way, it is possible to determine which part of the reinforcing bar is corroded and to confirm the anticorrosion effect precisely. In addition, it is possible to determine the degree of wear for each anode and to estimate the lifetime.

  In addition to the above-described point anode method, it can also be used in a galvanic anode method of a linear anode method. In this case, as shown in FIG. 6, a part of the lead wire 16 electrically connected to the linear anode 15 provided in an appropriate arrangement as shown in FIG. 6 is exposed on the surface of the reinforced concrete structure 1, and the lead wire The anticorrosion effect can be confirmed in the same manner as described above by measuring the current of the 16 exposed portions using the overhead wire current measuring device 10 described above.

  In the above-described example, the case of the galvanic anode method using the pointed anode method in which a large number of anode materials 3 are installed in the form of dots has been described. However, in the external power supply method using the pointed anode method as shown in FIG. Can be similarly implemented.

  In this case, the rebar-side conductive material 18 electrically connected to the rebar is connected to one electrode of the DC power source 17 and the lead wire 6 of each anode material 3 is branched to the other electrode of the power source 13. The electrically connected anode-side conductive material 19 is conducted. Then, by exposing each lead wire 6 to the outside of the reinforced concrete structure 1 in the same manner as described above, the current of the exposed portion is measured using the overhead wire current measuring device 10 as shown in FIG. Similarly, the anticorrosive effect can be confirmed.

DESCRIPTION OF SYMBOLS 1 Reinforced concrete structure 2 Internal reinforcing bar 3 Anode material 4 Anode installation hole 5 Filler 6 Lead wire 7 Anode-rebar conductive material 8 Groove 9 Filler 10 Overhead current measuring instrument 11 Sensor unit 15 Linear anode 16 Lead wire 17 DC power supply 18 Reinforcing bar side conductive material 19 Anode side conductive material

Claims (6)

A plurality of anode materials embedded in a reinforced concrete structure, and a conductive material connecting the anode material and the internal reinforcing bars, and corrosion of the internal reinforcing bars is suppressed by a potential difference generated between the anode material and the internal reinforcing bars. In the electric corrosion protection structure in the reinforced concrete structure
An electrically anticorrosive structure in a reinforced concrete structure, characterized in that at least a part of a conductive material for conducting the anode material and the internal rebar is exposed on an outer surface of the concrete structure.   2. The electrically anticorrosive structure in a reinforced concrete structure according to claim 1, wherein the exposed conductive material on the outer surface of the reinforced concrete structure is a non-corrosive conductive material.   The individual conductive material is electrically connected to each anode material, and at least a part of each individual conductive material is exposed on the surface of the reinforced concrete structure. Anti-corrosion structure. Provided with a plurality of anode materials embedded in a reinforced concrete structure, and provided with a conductive material connecting the anode material and the internal rebar, and the corrosion of the internal rebar is suppressed by the potential difference generated between the anode material and the internal rebar. It is an effect measurement method in the electrical anticorrosion structure made to do,
At least a part of the conductive material that conducts the anode material and the internal rebar is exposed on the surface of the reinforced concrete structure, and the current of the exposed portion of the conductive material from the reinforced concrete structure is measured using an overhead wire current measuring device. A method for measuring the effect of an electrically anticorrosive structure in a reinforced concrete structure.   The method for measuring the effect of an electrically anticorrosive structure in a reinforced concrete structure according to claim 4, wherein a non-corrosive conductive material is used as the conductive material exposed on the surface of the reinforced concrete structure.   The electrically conductive anticorrosive structure in a reinforced concrete structure according to claim 4, wherein the individual conductive materials are electrically connected to each anode material, and at least a part of each individual conductive material is exposed on the surface of the reinforced concrete structure. Effect measurement method.

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