Desalination apparatus and desalination method for concrete structures

Abstract

To provide a desalination apparatus and desalination method for concrete structures that can accurately supply current to the necessary anodes and perform desalination work safely and efficiently. [Solution] In this concrete structure desalination apparatus 2, the surface of the concrete structure 1 is divided into multiple construction target sections A1 to A3, and each construction target section A1 to A3 is equipped with an anode system 9 consisting of one or more linear anode units 8, 8... installed on the surface of the electrolyte solution holding layer 7 covering the surface of the concrete structure 1, and is equipped with a primary distribution means 11 that distributes current from a power supply 10 to each anode system 9, 9..., and each anode system 9 is equipped with a secondary distribution means 12 that distributes the current distributed from the primary distribution means 11 to each anode unit 8, 8..., so that the amount of current is controlled for each anode unit 8, 8....

Description

Technical Field

[0001] The present invention relates to a desalination device and a desalination method for a concrete structure in which steel materials such as reinforcing bars are embedded inside.

Background Art

[0002] In a concrete structure having steel materials such as reinforcing bars and PC steel materials inside, chloride ions penetrate inside due to salts flying from the sea, antifreeze agents sprayed on the road surface, etc., and the steel materials inside the concrete corrode, and the function of the structure may be impaired, resulting in a so-called "salt damage".

[0003] For such salt damage countermeasures, a temporary anode composed of an anode material, its holding material, and an electrolyte solution is installed on the surface of the concrete, and a direct current is supplied for a certain period between the steel material embedded in the concrete to extract chloride ions in the concrete to the outside of the concrete by electrophoresis. A desalination method is known.

[0004] Generally, in this desalination method, (1) it is necessary to be able to supply current to the concrete uniformly and stably during the energization period, (2) it is necessary to be able to suppress the generation of chlorine gas near the anode during the energization period, and (3) in the case of a structure that requires consideration of the alkali-silica reaction (ASR), it is required to use an electrolyte solution having an ASR progress suppression effect. In order to meet the requirements of (1) to (3) above, various methods such as the fiber method, the panel method, the bonding method, the simple water supply method, and the water absorption mat method have been developed.

[0005] Among these, the fiber method involves spraying cellulose fibers containing an electrolyte solution around a metal anode and holding the anode material with these cellulose fibers. It can be constructed even when the surface shape of the concrete is complex, and it is the most proven method because it can be constructed on both horizontal and vertical surfaces.

[0006] Furthermore, in this type of concrete desalination method, it is common to use a metal mesh as a planar anode, and this planar anode is covered with a coating material that can hold the electrolyte solution, with the steel material inside the concrete acting as the cathode, and a direct current (1.0 A / m² per concrete surface area) is applied. 2 The system involves running a solution (of a certain degree) for about eight weeks to extract chloride ions from the concrete, which are a cause of steel corrosion, from the concrete by electrophoresis (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2006-328886 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, with the conventional techniques described above, when a planar anode is used, it is difficult to grasp the planar current distribution of the planar anode, and it is also difficult to control the unevenness of the planar current distribution caused by the electrical resistance of the concrete, the amount of internal steel, and the amount of alkali around the anode.

[0009] Furthermore, if the current distribution becomes uneven, areas with low current flow may experience reduced desalination and fail to reach the desalination target, while areas with concentrated current may experience over-current.

[0010] In the event of excessive current flow, the amount of alkali penetration would concentrate, and in the case of concrete containing reactive aggregates, the ASR reaction could be accelerated, potentially causing cracks in the concrete.

[0011] Furthermore, when a planar anode is used, the current distribution becomes uneven, which reduces the coating material (catalyst) on the anode in areas with high current flow. Over time, this localized degradation increases electrical resistance, potentially leading to a loss of current flow.

[0012] On the other hand, in the case of the fiber method, which is commonly used in this type of desalination, there was a problem in that the used fibers could not be reused and were discarded as a large amount of industrial waste after desalination was complete.

[0013] Furthermore, the fiber method has material-related challenges such as frequent evaporation and leakage of the electrolyte solution, and because cellulose fibers are sprayed onto the concrete surface during construction, dust and other particles are generated, posing challenges in hygiene management for workers.

[0014] Therefore, in view of these conventional problems, the present invention aims to provide a desalination apparatus and desalination method for concrete structures that can accurately supply current to the necessary anodes and perform desalination work safely and efficiently. [Means for solving the problem]

[0015] The invention described in claim 1, which solves the conventional problems described above, is a desalination device for a concrete structure in which a steel material embedded in the concrete structure is used as the cathode, a direct current is supplied between the cathode and an anode placed on the surface of the concrete structure to remove chloride ions from the concrete, wherein the surface of the concrete structure is divided into a plurality of work area sections, and each work area section is provided with an electrolyte solution holding layer covering the surface of the concrete structure and an anode system consisting of one or more linear anode units installed on the surface of the electrolyte solution holding layer, and a power supply that supplies current between the anode system and the cathode, and a primary distribution means that distributes current from the power supply to each anode system, and each anode system is provided with a secondary distribution means that distributes the current distributed from the primary distribution means to each anode unit.

[0016] Furthermore, the features of the invention described in claim 2 are that, in addition to the configuration of claim 1, each anode unit constituting the anode system is connected in parallel, and each anode unit is provided with a detachable resistor connected in series.

[0017] Furthermore, a feature of the invention described in claim 3 is that, in addition to the configuration of claim 2, the resistor is either a fixed resistor or a variable resistor.

[0018] Furthermore, the features of the invention described in claim 4 are that, in addition to the configuration of claim 1, the anode unit comprises a linear anode material having a certain length, a backfill impregnated with an alkaline solution covering the linear anode material, and an insulating cover housing the backfill.

[0019] Furthermore, a feature of the invention described in claim 5 is that, in addition to the configuration of claim 1, the electrolyte solution holding layer is made of a sheet material consisting of a fibrous material or a continuously foamed material.

[0020] Furthermore, a feature of the invention described in claim 6 is a method for desalination of a concrete structure, in which a steel material embedded in the concrete structure is used as the cathode, a direct current is supplied between the cathode and an anode placed on the surface of the concrete structure to remove chloride ions in the concrete, wherein the surface of the concrete structure is divided into a plurality of construction target sections, the surface of the concrete structure is covered with an electrolyte solution retaining layer for each construction target section, and an anode system consisting of one or more linear anode units is installed on the surface of the electrolyte solution retaining layer, current from a power source that supplies current between each anode system and the cathode is distributed to each anode system through a primary distribution means, the distributed current is distributed to the anode units constituting each anode system through a secondary distribution means, and the amount of current is controlled for each anode unit.

[0021] The features of the invention according to claim 7 are, in addition to the configuration of claim 6, connecting each anode unit constituting the anode system in parallel, measuring the current amount of each anode unit, and then connecting a resistor in series with any one of the anode units as necessary to control the current amount of each anode unit.

[0022] The features of the invention according to claim 8 are, in addition to the configuration of claim 7, forming the resistor with a fixed resistor or a variable resistor and controlling the current amount of each anode unit by appropriately changing the resistance value.

[0023] The features of the invention according to claim 9 are, in addition to the configuration of claim 6, arranging each anode unit in accordance with the position of the steel material embedded in the concrete structure.

Advantages of the Invention

[0024] The desalination device for a concrete structure according to the present invention, by having the configuration according to claim 1, enables grasping of the energization amount for each construction target section and each anode unit constituting the anode system of each construction target section, and makes it easy to control the non-uniformity of the current distribution for each construction target section, equalize the desalination rates of a plurality of construction target sections, and improve the quality. Further, since it is possible to avoid local concentration of current, the amount of alkali penetration does not concentrate either, and even in concrete containing reactive aggregates, it is possible to suppress cracking of the concrete due to acceleration of the ASR reaction.

[0025] Also, in the present invention, by having the configuration according to claims 2 to 3, the current amount of each anode unit can be controlled with a simple structure.

[0026] Furthermore, in the present invention, by having the configuration according to claim 4, when there is partial deterioration of the anode, it can be dealt with by replacing the unitized members. Also, the anode unit can be reused after the energization operation, and by repeatedly using it, reduction of industrial waste and reduction of material costs can be achieved.

[0027] Furthermore, by incorporating the configuration described in claim 5, unlike conventional fiber methods, the use of cellulose fibers is eliminated, thereby drastically reducing industrial waste. Additionally, there is no dust damage during construction, allowing for hygienic, safe, and efficient construction.

[0028] The desalination method for concrete structures according to the present invention, by having the configuration described in claim 6, makes it possible to grasp the amount of current flow for each construction target section and for each anode unit constituting the anode system of each construction target section, and makes it easy to control the unevenness of the current distribution for each construction target section, thereby standardizing the desalination rate of multiple construction target sections and improving quality. Furthermore, since it is possible to avoid localized current concentration, the amount of alkali penetration does not concentrate, and even in concrete containing reactive aggregates, it is possible to suppress concrete cracking due to the acceleration of the ASR reaction.

[0029] Furthermore, by incorporating the configurations described in claims 7 to 8, the current amount of each anode unit can be controlled with a simple structure.

[0030] Furthermore, by incorporating the configuration described in claim 9, the present invention is effective in desalination near the internal steel material where desalination is required, and since the entire construction target section is covered with an electrolyte solution holding layer, current can be easily distributed between anode units, thereby improving the desalination effect between anode units. [Brief explanation of the drawing]

[0031] [Figure 1] This is a side view showing an example of a concrete structure using the concrete structure desalination device according to the present invention. [Figure 2] This is a longitudinal cross-section of the same image. [Figure 3] This is a schematic circuit diagram of the desalination apparatus described above. [Figure 4]This is a partially enlarged schematic cross-sectional view showing the state of the anode unit shown above. [Figure 5] A block diagram showing an example of the secondary distribution means described above. [Modes for carrying out the invention]

[0032] Next, an embodiment of the desalination apparatus for concrete structures according to the present invention will be described based on the example shown in Figures 1 to 5. In the figures, reference numeral 1 denotes a concrete structure, and reference numeral 2 denotes the desalination apparatus.

[0033] In this embodiment, a reinforced concrete T-girder 1 erected between the piers of a bridge will be used as an example of concrete structure 1, and the same reference numerals will be used for concrete structures and T-girders as appropriate.

[0034] As shown in Figures 1 and 2, the T-girder 1 integrally comprises a wall-shaped web portion 3 having a constant width that is continuous in the bridge axis direction, and a flat plate-shaped flange portion 4 integrally supported at the upper end of the web portion 3, and is formed so that the T-shaped cross section is continuous in the bridge axis direction.

[0035] As shown in Figure 2, this T-girder 1 is made of reinforced concrete with multiple reinforcing bars (main bars 5, 5…) positioned at a certain distance (cover) from the surface of the web portion 3 and flange portion 4, with their axial direction oriented toward the bridge axis, and reinforcing bars 6 arranged in a direction intersecting the bars 5, 5….

[0036] As shown in Figures 1 to 3, the desalination device 2 for the concrete structure 1 (hereinafter referred to as the desalination device) is configured such that the surface of the concrete structure, a T-girder 1, is divided into multiple construction target sections A1, A2, and A3. Each construction target section A1, A2, and A3 is equipped with an electrolyte solution holding layer 7 that covers the surface of the concrete structure 1, and an anode system 9 consisting of one or more linear anode units 8, 8... installed on the surface of the electrolyte solution holding layer 7. A direct current is supplied between the cathode, which is made of steel materials 5, 6 embedded in the concrete structure 1, and the anode system 9 to remove chloride ions from the concrete.

[0037] Furthermore, the desalination apparatus 2 includes a power supply 10 that supplies current between the anode system 9 and the steel materials 5 and 6 that form the cathode, and a primary distribution means 11 that distributes current from the power supply 10 to each anode system 9. The current (amount of current) distributed to each anode system 9 is then distributed to each anode unit 8, 8... by a secondary distribution means 12, allowing any current (including no current) to be passed through each anode unit 8, 8....

[0038] There are no particular restrictions on the designation of the construction target areas A1, A2, and A3, but the shape of the concrete structure 1 and the arrangement of the internal steel members (main reinforcement 5, 5..., reinforcing reinforcement 6) are important. For example, in the T-girder 1 of this embodiment, the areas are the two lower surfaces of the flange portion 4 (A1, A1), the two side surfaces of the web portion 3 (A2, A2), and the lower surface of the web portion 3 (A3), which are located symmetrically on either side of the T-girder 1, and the areas obtained by dividing these into multiple sections along the bridge axis are designated as construction target areas A1, A2, and A3, respectively.

[0039] The electrolyte solution retaining layer 7 is made of a sheet material consisting of paper fiber material or continuous foam, and is attached to cover the entirety of each construction target section A1, A2, and A3 of the concrete structure 1, so that the electrolyte solution is supplied to this electrolyte solution retaining layer 7 continuously or intermittently.

[0040] Furthermore, each of the construction target sections A1, A2, and A3 may have the electrolyte solution holding layer 7 formed by one sheet material, or it may have the electrolyte solution holding layer 7 formed by multiple sheet materials.

[0041] The sheet material can be any sheet material that possesses water retention and a certain level of strength. For example, hydrophilic fibers such as regenerated fibers like rayon or natural fibers like cotton can be dispersed in water, flattened into a sheet using a sieve, and then dehydrated and dried (paper fiber material) can be used.

[0042] Furthermore, the sheet material may be a nonwoven fabric made of hydrophilic synthetic fibers such as polyethylene or polypropylene, polyester, or polyamide, or it may be composed of an open-cell body obtained by chemically crosslinking polyethylene resin to create a complex network polymer structure.

[0043] This electrolyte solution retaining layer 7 is formed to ensure sufficient water retention according to the electrolyte solution used, thereby maintaining the wet state of the concrete.

[0044] The electrolyte solution is an aqueous solution in which lithium, sodium, and potassium are dissolved in water, along with solutes such as carbonates, nitrates, nitrites, sulfates, borates, hydroxides, and chlorides of magnesium and calcium, and is designed to facilitate the flow of electricity by penetrating into concrete.

[0045] This electrolyte solution, although not specifically shown in the diagram, is supplied from the electrolyte solution storage tank through supply pipes, etc., to the electrolyte solution holding layers 7 provided in each construction target section A1, A2, and A3. After supply, the amount that flows down from the electrolyte solution holding layers 7 is recovered, and the recovered electrolyte solution is returned to the electrolyte solution storage tank to circulate.

[0046] A DC power source such as a general battery is used for the power supply 10, and the primary distribution means 11 distributes the current to the anode systems 9 installed in each construction target area A1, A2, and A3 by means of, for example, a DC power distribution device.

[0047] A DC power distributor is equipped with a current distribution circuit and can distribute the input from the DC power supply 10 to multiple (parallel) DC current outputs, and a general commercially available product can be used.

[0048] Furthermore, the form of the primary distribution means is not limited to the DC distributor described above. For example, it may simply be a bundle of multiple wires using a sleeve or the like, or multiple wires may be directly connected to the positive terminal of a DC power supply and then bundled together.

[0049] The current output from this primary distribution means 11 is connected to the steel materials (main reinforcement bars 5, 5... and reinforcing bars 6) embedded in the concrete that constitute the cathode, with the negative electrode output connected to each anode system 9.

[0050] In this embodiment, current is distributed from a single power source 10 to all anode systems 9 via a primary distribution means 11. However, the desalination apparatus 2 may be equipped with multiple power sources 10, and current may be distributed from each power source 10 to the corresponding multiple anode systems 9 via the primary distribution means 11.

[0051] As shown in Figure 3, the anode system 9 consists of one or more linear anode units 8, 8… arranged in parallel at intervals from each other on the surface of the electrolyte solution holding layer 7 in each construction target section A1, A2, A3, with their axial direction oriented toward the bridge axis. The current supplied via the primary distribution means 11 is distributed to each anode unit 8, 8… constituting each anode system 9 by the secondary distribution means 12.

[0052] Each anode unit 8, 8… is preferably positioned in accordance with the location of the steel members 5, 5… embedded in the concrete structure 1. For example, they are positioned parallel to the main reinforcement bars 5, 5… in line with the vertical spacing of the main reinforcement bars 5, 5… in the bridge axis direction of the T-girder 1.

[0053] As shown in Figures 1 and 4, the anode units 8, 8… each comprise a linear anode material 13 having a certain length, a backfill 14 impregnated with an alkaline solution covering the linear anode material 13, and an insulating cover 15 made of an insulating resin with a U-shaped cross-section that houses the backfill 14, and are formed in a rod shape having a certain length (for example, about 0.5 to 2.0 m). The form of the anode unit 8 is not limited to this embodiment, and any form is acceptable as long as it is rod-shaped and can exhibit performance equivalent to that of the above embodiment as an anode in a desalination device.

[0054] These anode units 8, 8… are fixed to the surface of the concrete structure 1 by fasteners (not shown) with the open side of the insulating cover 15 facing the electrolyte solution holding layer 7, and the backfill 14 in contact with the electrolyte solution holding layer 7.

[0055] Furthermore, these anode units 8,8... are manufactured in a pre-assembled state at the factory, and the anode unit 8 can be installed independently and detachably.

[0056] Furthermore, the anode units 8, 8... may have a portion of the linear anode material 13 (terminal portion) exposed, or may be equipped with connectors for connection, in order to facilitate connection with the branch wires 17, 17... described later.

[0057] The secondary distribution means 12 includes a main wire 16 connected to the primary distribution means 11, and branch wires 17, 17... that branch off from the main wire 16 and are connected to the linear anode material 13 of each anode unit 8, 8..., forming a parallel circuit (branch circuit).

[0058] Furthermore, the secondary distribution means 12 is equipped with resistors 18, 19 that can be attached and detached in series with anode units 8, 8, etc. on the branch wires 17, 17, etc., and as shown in Figure 5, the amount of current can be controlled for each anode unit 8, 8, etc. by installing the resistors 18, 19 on any branch wire 17, 17, etc.

[0059] The resistors 18 and 19 may be either fixed resistors 18 or variable resistors 19. In the case of fixed resistors 18, any resistor 18 with any resistance value necessary to obtain the desired amount of current is used, and in the case of variable resistors 19, the resistance value is changed to obtain the desired amount of current.

[0060] Furthermore, the resistance values ​​of resistors 18 and 19 are determined by measuring the current value of each branch circuit before the desalination process, and adjusting them to a predetermined current level if excessive current is flowing. Current can be measured using a clamp-type ammeter, or fixed ammeters may be installed in each branch circuit.

[0061] Next, a method for desalination of concrete structure 1 using the desalination apparatus 2 described above will be explained. Components similar to those in the above-described embodiment will be denoted by the same reference numerals. Furthermore, the explanation of the desalination method will be based on the figures used in the explanation of the desalination apparatus.

[0062] First, as a preliminary step, the arrangement and condition (presence or absence of corrosion, etc.) of the steel materials (main reinforcement bars 5,5..., reinforcing bars 6) embedded in the target concrete structure 1 (in this embodiment, T-beam 1) are determined by the specifications, design drawings, or prior inspections.

[0063] Then, based on the arrangement of the steel members 5 and 6 as determined above, and more specifically the amount of reinforcement in the steel members 5 and 6, the surface of the concrete structure 1 is divided into multiple construction target sections A1, A2, and A3. For example, it is divided into the lower surface of the web section 3 (A3), which has a relatively large amount of reinforcement in the web section 3; the lower surfaces of both flange sections 4 (A1, A1), which are symmetrically located with the T-girder 1 in between, which has less reinforcement than the lower surface of the web section 3; and the two sides of the web section 3 (A2, A2).

[0064] Next, once the construction areas A1, A2, and A3 are completed, a water-retentive sheet material is attached to each of the construction areas A1, A2, and A3 to form an electrolyte solution retaining layer 7. Although not specifically shown in the diagram, piping such as supply pipes for supplying the electrolyte solution to the electrolyte solution retaining layer 7 is also installed.

[0065] Then, after the installation of the electrolyte solution holding layer 7 is complete, anode units 8, 8… that constitute the anode system 9 are installed on the surface of the electrolyte solution holding layer 7 for each of the construction target sections A1, A2, and A3.

[0066] Specifically, anode units 8, 8… are positioned in accordance with the locations of the steel materials (main reinforcement bars 5, 5… in this embodiment) embedded in the concrete, and then secured with fasteners.

[0067] In the lower surface of the web section 3, where there is a large amount of reinforcement, the anode units 8,8... are spaced closely together, while in the side surfaces of the web section 3 and the lower surface of the flange section 4, where there is a relatively small amount of reinforcement, the anode units 8,8... are spaced more widely apart.

[0068] Next, the power supply 10 and the primary distribution means 11 (DC power distributor) are installed in predetermined locations, multiple main power lines 16 are distributed (branched) from the primary distribution means 11, and multiple branch power lines 17, 17… that branch off from the main power lines 16 corresponding to the anode systems 9 installed in each construction target area A1, A2, A3 are connected to each anode unit 8, 8… of each anode system 9.

[0069] On the other hand, the negative terminal output of the primary distribution means 11 (DC power distributor) is connected to steel materials (main reinforcement bars 5, 5..., reinforcing bars 6) embedded in the concrete structure 1, which is the cathode.

[0070] Next, the electrolyte solution is supplied from the electrolyte solution storage tank to the electrolyte solution holding layers 7 installed in each construction target section A1, A2, and A3 via supply pipes, etc., and current is supplied between the cathode steel materials 5, 6 and the anode units 8, 8… of each anode system 9. In this state, the amount of current in each branch power line 17, 17… is measured using a clamp-type grounding ammeter, etc. (current measurement work).

[0071] In this case, the amount of current from the anode units 8, 8, etc. may differ depending on the dry and wet state of the concrete structure 1 and the degree of corrosion of the steel materials (main reinforcement bars 5, 5, etc. and reinforcing bars 6).

[0072] Then, once the measurement of the current is complete, the supply of the electrolyte solution and the power supply are temporarily stopped, and according to the measured current, resistors 18, 19 are installed in series with the anode units 8, 8, ... on the branch wires 17, 17, ... at the points with high current, as shown in Figure 5, to form a secondary distribution means 12, and the current is controlled for each anode unit 8, 8, ... that constitutes each anode system 9.

[0073] Next, once the secondary distribution means 12 is set up, the supply of electrolyte solution and the energization are restarted, and the current density per surface area of ​​the reinforcing bars (steel materials) is set to 1.0 A / m² per concrete surface area. 2 The power is kept on for about 8 weeks to achieve a certain level of corrosion, and chloride ions in the concrete that cause corrosion of steel materials 5 and 6 are extracted from the concrete by electrophoresis.

[0074] In this process, the anode units 8,8… are positioned in accordance with the locations of the steel materials 5,5…, so a sufficient desalination effect can be obtained near the internal steel materials where desalination is required. Furthermore, since each construction target section A1, A2, and A3 is covered with an electrolyte solution holding layer 7 and the anode units 8,8… are installed on its surface, current can be easily distributed between the parallel anode units 8,8, improving the desalination effect between the anode units 8,8….

[0075] Next, while power is supplied, the current amount of each anode unit 8,8… is measured periodically, and resistors 18,19 are newly installed or their resistance values ​​are adjusted in series with the anode units 8,8… on the branch wires 17,17… where the current amount of the secondary distribution means 12 is large. If the current amount is small, the installed resistors 18,19 are removed, and the current amount is controlled for each anode unit 8,8… that constitutes each anode system 9.

[0076] Furthermore, if the linear anode material 13 deteriorates partially, the entire anode unit 8, 8... is replaced.

[0077] Then, once desalination is complete, the wires and piping for supplying the electrolyte solution that make up the anode units 8, 8..., power supply 10, primary distribution means 11, and secondary distribution means 12 are removed, and the sheet material that makes up the electrolyte solution holding layer 7 is peeled off from the surface of the concrete structure 1.

[0078] The anode units 8,8... are modular and can be easily removed, and if usable, they can be reused.

[0079] On the other hand, if the sheet material constituting the electrolyte solution holding layer 7 is made of paper fiber, it can be disposed of as combustible waste after drying, thereby reducing industrial waste.

[0080] The desalination apparatus 2 and method for concrete structures 1 configured in this way distribute current to each of the multiple partitioned construction target sections A1, A2, A3, and further control the amount of current for each of the multiple independent anode units 8, 8... that form a circuit, thereby suppressing the uneven distribution of current in each construction target section A1, A2, A3 and achieving precise current supply.

[0081] Therefore, in the present invention, the desalination rates of multiple construction target sections A1, A2, and A3 can be made roughly the same, and it is possible to avoid the occurrence of areas in the concrete structure 1 that do not partially reach the desalination target.

[0082] Furthermore, in this invention, since the current distribution is uniform, localized current concentration can be prevented. Therefore, alkali penetration does not concentrate, and even in concrete containing reactive aggregates, cracking of the concrete due to the acceleration of the ASR reaction (alkali-silica reaction) can be suppressed.

[0083] In the above embodiment, a T-beam 1 was used as an example of the concrete structure 1, but the form of the concrete structure 1 is not limited to this, and can be applied to any concrete structure 1 in which steel materials are embedded inside.

[0084] Furthermore, the configuration of the secondary distribution means 12 is not limited to the above-described embodiment. For example, a switch circuit that interrupts the supply of current in the event of an overcurrent may be incorporated instead of, or in combination with, the resistors 18 and 19. [Explanation of Symbols]

[0085] 1. Concrete structure (T-beam) 2 Desalination equipment 3. Web Department 4. Flange section 5. Reinforcement bars (main reinforcement) 6. Reinforcement muscles 7. Electrolyte solution holding layer 8 Anode Units 9. Anode System 10 Power supply 11 Primary distribution means 12 Secondary distribution means 13 Linear Anode Material 14 Backfill 15 Insulating cover 16 Main electrical wire 17 Branch wires 18 fixed resistor 19 Variable resistor

Claims

1. In a desalination apparatus for concrete structures, in which a steel material embedded within the concrete structure is used as the cathode, and a direct current is supplied between the cathode and an anode placed on the surface of the concrete structure to remove chloride ions from the concrete, The surface of the aforementioned concrete structure is divided into multiple construction target areas, Each section to be constructed comprises an electrolyte solution retaining layer covering the surface of the concrete structure, and an anode system consisting of one or more linear anode units installed on the surface of the electrolyte solution retaining layer, The system comprises a power supply that supplies current between the anode system and the cathode, and a primary distribution means that distributes current from the power supply to each anode system. A desalination apparatus for concrete structures, characterized in that each anode system is provided with a secondary distribution means that distributes the current distributed from the primary distribution means to each anode unit.

2. The desalination apparatus for concrete structures according to claim 1, wherein each anode unit constituting the anode system is connected in parallel, and a resistor that can be attached to and detached in series with each anode unit is provided.

3. The desalination apparatus for concrete structures according to claim 2, wherein the resistor is a fixed resistor or a variable resistor.

4. The desalination apparatus for concrete structures according to claim 1, wherein the anode unit comprises a linear anode material having a certain length, a backfill impregnated with an alkaline solution covering the linear anode material, and an insulating cover housing the backfill.

5. The desalination apparatus for concrete structures according to claim 1, wherein the electrolyte solution holding layer is composed of a sheet material made of a fibrous material or a continuously foamed material.

6. In a method for desalination of a concrete structure, in which a steel material embedded within the concrete structure is used as the cathode, and a direct current is supplied between the cathode and an anode placed on the surface of the concrete structure to remove chloride ions from the concrete, The surface of the aforementioned concrete structure is divided into multiple construction target areas, For each section to be constructed, the surface of the concrete structure is covered with an electrolyte solution retaining layer, and an anode system consisting of one or more linear anode units is installed on the surface of the electrolyte solution retaining layer. A method for desalination of concrete structures, characterized by distributing current from a power source that supplies current between each anode system and the cathode to each anode system through a primary distribution means, distributing the distributed current to anode units constituting each anode system through a secondary distribution means, and controlling the amount of current for each anode unit.

7. The method for desalination a concrete structure according to claim 6, wherein each anode unit constituting the anode system is connected in parallel, the amount of current in each anode unit is measured, and a resistor is connected in series with any of the anode units as necessary to control the amount of current in each anode unit.

8. The method for desalination a concrete structure according to claim 7, wherein the resistor is composed of a fixed resistor or a variable resistor, and the amount of current in each anode unit is controlled by changing the resistance value as appropriate.

9. The method for desalination of a concrete structure according to claim 6, wherein each of the anode units is positioned in accordance with the location of the steel material embedded in the concrete structure.

Images