JP6858026B2 - Electrocorrosion protection method, concrete structure and manufacturing method of concrete structure - Google Patents

Description

The present invention relates to an electrolytic corrosion protection method, a concrete structure, and a method for manufacturing a concrete structure.

The concrete structure may have internal voids and surface cracks due to deterioration over time. When steel materials such as reinforcing bars, steel frames, and PC steel materials are buried in the concrete structure, water and chloride enter from the outside through internal voids and surface cracks, and chloride ions generate corroded parts in the steel material. Salt damage may occur.

As a method of suppressing salt damage, an external power supply type electrocorrosion protection method is known in which an anode material is installed in a concrete structure, a steel material is used as a cathode, and an anticorrosion current is continuously passed from an external power source to the steel material. The external power supply type electrocorrosion protection method is related to the corrosion of the steel material by injecting an anticorrosion current from the power supply into the steel material and polarizing the steel material so that the surface potential difference between the corroded part and the sound part of the steel material becomes small. It delays the progress of the anodic reaction and reduces the corrosion rate of the steel material.

However, in many concrete structures, steel materials are arranged in multiple stages in the internal region, and there are restrictions on the part where the anode material can be installed due to the structure. Therefore, even if the steel material is buried in the same concrete structure, the current density of the anticorrosion current flowing into the surface of the steel material varies depending on the positional relationship between the anode material and the steel material, and the polarization amount is the anticorrosion reference value. There is a possibility that some steel materials will not reach. For example, when the concrete structure is a bridge slab, the anode material can be installed only on the lower surface, and the current density of the anticorrosion current flowing into the steel surface near the lower surface is higher than the current density of the anticorrosion current flowing into the steel surface on the road surface side away from the lower surface. The current density of the anticorrosion current is reduced. As a result, the current density of the anticorrosion current flowing into the surface of the steel material varies among the steel materials, and there is a possibility that the steel material whose polarization amount does not reach the anticorrosion reference value may be generated.

Further, in the concrete structure, the concentration distribution of chloride ions in the internal region is uneven, and the corrosive environment of the steel material may differ depending on the position of the steel material. For example, the region on the surface side of the structure tends to have a higher chloride ion concentration than the inner region due to the influence of salt infiltration from the outside. Such a difference in the corrosive environment also causes a variation in the current density of the anticorrosion current supplied to the surface of the steel material among the steel materials, which causes the steel material whose polarization amount does not reach the anticorrosion standard value.

Therefore, in order to supply the optimum anticorrosion current to the steel material according to the difference in the corrosive environment, Patent Document 1 describes the surface side steel material arranged in the surface side region and the inner side arranged inside the surface side steel material. In a concrete structure having a steel material, it has been proposed to separately form an electrocorrosion protection circuit including a surface side steel material and an electrocorrosion protection circuit including an inner steel material.

Japanese Unexamined Patent Publication No. 2015-145524

However, since the surface side steel material and the inner steel material are often assembled by connecting a part of them to each other as a framework of a concrete structure such as a reinforcing bar or a steel frame, they are electrically connected in the concrete structure. Often in a state. Therefore, even if the electrocorrosion circuit is formed separately as described above, the anticorrosion current tends to flow into the steel material close to the anode material instead of the steel material electrically connected as the electrocorrosion protection circuit. Steel materials with a low amount of polarization are likely to occur.

In the above case, it is conceivable to increase the supply amount of the anticorrosion current according to the steel material having a low polarization amount so that the polarization amount of all the steel materials satisfies the anticorrosion standard. However, in this case, since the steel material at a position where the anticorrosion current is easily supplied is in an overcorrosion state, the load on the electrocorrosion device including the anode material may increase and the durability of the electrocorrosion device may decrease. ..

On the other hand, as described above, there is a bias in the chloride ion concentration distribution in the concrete structure, but this bias varies not only with the position in the concrete structure but also with the installation environment and application of the concrete structure. For example, when the concrete structure is a bridge slab, calcium chloride may be sprayed on the road surface of the concrete structure as an antifreeze agent. Therefore, when the concrete structure is a bridge slab, the road surface side portion has a higher chloride ion concentration and a faster corrosion rate than the lower surface side portion facing the road surface. As described above, in many cases, the anode material can be installed only on the lower surface of the bridge slab, and such a bias in the chloride ion concentration distribution is caused by the variation in the current density of the anticorrosion current between the steel materials and the amount of polarization. This is a factor that increases the possibility that steel materials that do not reach the anticorrosion standard value will be generated.

Therefore, the present invention reduces the variation in the current density of the anticorrosion current between the steel materials and the possibility of occurrence of the steel material whose polarization amount does not reach the anticorrosion reference value without lowering the durability of the electrocorrosion protection device including the anode material. It is an object of the present invention to provide an electrocorrosion protection method, a concrete structure and a method for manufacturing a concrete structure, which can be used.

(1) The electrocorrosion protection method according to the embodiment of the present invention is a concrete structure in which a steel material is embedded, in an outer surface including a target surface, an inner region surrounded by the outer surface, and the inner region. The distance between the first steel material buried and the second steel material buried in the internal region, and the distance between the second steel material and the target surface is greater than the distance between the first steel material and the target surface. A linear anode material installation step of installing a plurality of linear anode materials so as to extend in the longitudinal direction along the target surface in a concrete structure including a second steel material arranged so as to be long. The first anticorrosion method comprises a rod-shaped anode material installation step of installing a plurality of rod-shaped anode materials on the concrete structure so that the longitudinal direction extends from the outer surface toward the inner region. The steel material and the plurality of linear anode materials are electrically connected to the first external power source, and the second steel material and the plurality of rod-shaped anode materials are electrically connected to the second external power source. The linear anode material and the rod-shaped anode material are installed so that the sum of the surface surfaces of the plurality of rod-shaped anode materials is equal to or greater than the sum of the surface surfaces of the plurality of linear anode materials.
(2) The electrocorrosion protection method according to the embodiment of the present invention is the electrocorrosion protection method described in (1) above, and the rod-shaped anode material installation step is performed in a region sandwiched between the plurality of linear anode materials. It may include a step of forming the plurality of insertion holes in the target surface and a step of inserting the rod-shaped anode material into the insertion holes.
(3) The electrocorrosion protection method according to the embodiment of the present invention is the electrocorrosion protection method according to (1) or (2) above, and in the rod-shaped anode material installation step, the end portion on the internal region side and the said. The rod shape including the end on the outer surface side so that the distance between the end on the inner region side and the second steel material is shorter than the distance between the end on the inner region side and the first steel material. An anode material may be installed.
(4) The electrocorrosion protection method according to the embodiment of the present invention is the electrocorrosion protection method according to any one of (1) to (3) above, and the plurality of rods are formed in the rod-shaped anode material installation step. The rod-shaped anode material may be installed so that the plurality of rod-shaped anode materials are arranged in a staggered manner in a cross section across the anode material.
(5) The concrete structure according to the embodiment of the present invention is a concrete structure in which a steel material is embedded, and is located in an outer surface including a target surface, an inner region surrounded by the outer surface, and the inner region. The first steel material buried and the second steel material buried in the internal region, the distance between the second steel material and the target surface is greater than the distance between the first steel material and the target surface. A second steel material arranged so as to be long, a plurality of linear anode materials whose longitudinal direction extends along the target surface, and a plurality of rod-shaped anodes whose longitudinal direction extends from the outer surface toward the inner region. The material, the first external power source electrically connected to the first steel material and the plurality of linear anode materials, and the second steel material and the plurality of rod-shaped anode materials are electrically connected to each other. The linear anode material and the rod-shaped anode material are provided with a second external power source so that the sum of the surface areas of the plurality of rod-shaped anode materials is equal to or greater than the sum of the surface areas of the plurality of linear anode materials. It is provided.
(6) The method for manufacturing a concrete structure according to an embodiment of the present invention is a concrete structure in which a steel material is embedded, the outer surface including the target surface, the inner region surrounded by the outer surface, and the above. The first steel material buried in the internal region and the second steel material buried in the internal region, the distance between the second steel material and the target surface is the distance between the first steel material and the target surface. Installation of a plurality of linear anode materials so as to extend in the longitudinal direction along the target surface in a concrete structure including a second steel material arranged so as to be longer than the distance of A method for manufacturing a concrete structure, comprising a step and a rod-shaped anode material installation step of installing a plurality of rod-shaped anode materials on the concrete structure so that the longitudinal direction extends from the outer surface toward the inner region. The first steel material and the plurality of linear anode materials are electrically connected to the first external power source, and the second steel material and the plurality of rod-shaped anode materials are connected to the second external power source. The linear anode material and the rod-shaped anode material are installed so that the sum of the surface areas of the plurality of rod-shaped anode materials is equal to or greater than the sum of the surface areas of the plurality of linear anode materials. is there.

The present invention reduces the variation in the current density of the anticorrosion current between the steel materials and the possibility that the steel material whose polarization amount does not reach the anticorrosion reference value is generated without significantly reducing the durability of the electrocorrosion protection device including each anode material. can do.

It is a process explanatory drawing which shows typically the electric corrosion protection method which concerns on embodiment of this invention. (A) is a schematic view explaining the rod-shaped anode material used in the electro-corrosion protection method according to the embodiment of the present invention, and (b) is the linear anode material used in the electro-corrosion protection method according to the embodiment of the present invention. It is a schematic diagram to explain. It is a bottom view of the concrete structure of the electrolytic corrosion protection method which concerns on embodiment of this invention. FIG. 3 is a cross-sectional view taken along the line AA'in FIG. It is sectional drawing in the BB' cross section of FIG. It is a bottom view of the concrete structure which concerns on Example 2 of this invention. It is sectional drawing in the CC'cross section of FIG. It is sectional drawing in the DD'cross section of FIG. It is a graph which shows the variation of the current density of the anticorrosion current flowing into each reinforcing bar surface of the concrete structure which concerns on Example 1 of this invention. It is a graph which shows the variation of the current density of the anticorrosion current flowing into each reinforcing bar surface of the concrete structure which concerns on Example 2 of this invention. It is a graph which shows the variation of the current density of the anticorrosion current flowing into each reinforcing bar surface of the concrete structure which concerns on Comparative Example 1 of this invention. It is a graph which shows the variation of the current density of the anticorrosion current flowing into each reinforcing bar surface of the concrete structure which concerns on Comparative Example 2 of this invention. It is a graph which shows the variation of the current density of the anticorrosion current flowing into each reinforcing bar surface of the concrete structure which concerns on Comparative Example 3 of this invention. It is a bottom view of the concrete structure to which the electrocorrosion protection method which concerns on embodiment of this invention is applied. It is sectional drawing in sectional view E of FIG. It is sectional drawing in the cross section F of FIG.

The present invention relates to an electrocorrosion protection method for suppressing salt damage of the concrete structure 100. The electric corrosion protection method of the present invention is a method of installing an electric corrosion protection device on the concrete structure 100, and when the electric corrosion protection method of the present invention is carried out, the concrete structure 100 and the electric corrosion protection device installed on the concrete structure 100 are combined. A concrete structure 300 including the concrete structure 300 is manufactured. The concrete structure 100 to which the electrocorrosion protection method of the present invention is applied includes both a concrete structure before the progress of deterioration due to salt damage and a concrete structure after the progress of deterioration. Further, in the present invention, concrete is used as a concept including not only concrete but also cement and mortar. The steel material is a known concrete structural steel material including reinforcing bars, steel frames and PC steel materials, and is used as a concept including a concrete reinforcing steel material and a tension material for prestressed concrete. Examples of the concrete structure 100 include reinforced concrete structures such as bridge slabs, bridge girders, columns, and beams.

The electrocorrosion protection method according to the embodiment of the present invention will be described with reference to FIGS. 1, 3 to 5, and 14 to 16. FIG. 1 is a process explanatory view schematically showing the electrocorrosion protection method of the present embodiment, and FIGS. 3 to 5 show a concrete structure 300 obtained by applying the electrocorrosion protection method of the present embodiment to the concrete structure 100. FIG. 3 is a schematic view, FIG. 3 is a bottom view of the concrete structure 300, FIG. 4 is a cross-sectional view taken along the line AA'of FIG. 3, and FIG. 5 is a cross-sectional view taken along the line BB' of FIG. .. In FIGS. 3 to 5, the first external power supply X and the second external power supply Y are not shown. 14 to 16 are views showing a concrete structure 100 to which the anticorrosion method according to the embodiment of the present invention is applied, FIG. 14 is a perspective view, FIG. 15 is a sectional view in cross section E of FIG. 14, and FIG. Is a cross-sectional view of the cross section F of FIG.

The electrocorrosion protection method according to the embodiment of the present invention is a method of performing electrocorrosion protection on such a concrete structure 100 by using both the point-shaped anode method and the linear anode method. In the point-shaped anode method, the rod-shaped anode material is installed in the concrete structure 100 so that the longitudinal direction extends from the outer surface toward the inner region. Further, in the linear anode method, an elongated strip-shaped linear anode material is installed in the concrete structure 100 so that the longitudinal direction extends along the outer surface 100S of the concrete structure 100.

As shown in FIGS. 1A and 14 to 16, the concrete structure 100 includes an outer surface 100S including a target surface and an inner region 100i surrounded by the outer surface 100S, and a plurality of concrete structures 100 in the inner region 100i. Steel materials 1 to 19 of the above are buried. In the concrete structure 100, the outer surface 100S includes an upper surface 100U, a bottom surface 100B, and a side surface 100L. In the present embodiment, the target surface will be described as the bottom surface 100B. In the present invention, the direction of penetrating the upper surface 100U and the bottom surface 100B facing the upper surface 100U is referred to as a thickness direction. In the present invention, the side view means viewing from the side with respect to the target surface.

In the present embodiment, as shown in FIGS. 3 to 5, three linear anode materials 211a to 211c and 16 rod-shaped anode materials 231a to 231i are installed on the bottom surface 100B of the concrete structure 100 to form a steel material. Performs 1 to 19 electroprotection. The steel materials 1 to 19 include the first steel material 1,2,3,7,8,9,10,11, the second steel material 4,5,6,12,13,14,15,16 and the laterally tightened steel material17. , 18, 19 are included. As shown in the figure, in the steel materials 1 to 19, the distance between the second steel materials 4, 5, 6, 12, 13, 14, 15, 16 and the bottom surface 100B is the first steel material 1, 2, 3, 7, It is arranged so as to be longer than the distance between 8, 9, 10, and 11 and the bottom surface 100B. That is, the first steel materials 1, 2, 3, 7, 8, 9, 10, 11 and the second steel materials 4, 5, 6, 12, 13, 14, 15, 16 are from the top surface 100U to the bottom surface 100B. It is arranged in multiple stages in the direction of thickness toward which it faces, and is arranged in two stages in the figure.

In the present embodiment, the concrete structure 100 includes a first steel material 1,2,3,7,8,9,10,11 and a second steel material 4,5,6,12,13,14,15, A connecting steel material connecting with 16 may be further included. In this case, the first steel materials 1, 2, 3, 7, 8, 9, 10, 11 and the second steel materials 4, 5, 6, 12, 13, 14, 15, 16 are the concrete structure 100. It is electrically connected in the internal area 100i.

For example, the first steel materials 1, 2, 3, 7, 8, 9, 10, and 11 are buried in a region of 3 cm or more and 10 cm or less, preferably 7 cm or more and 10 cm or less from the bottom surface 100B of the concrete structure 100. Further, for example, the second steel materials 4, 5, 6, 12, 13, 14, 15, 16 are buried in a region of 3 cm or more and 10 cm or less, preferably 7 cm or more and 10 cm or less from the upper surface 100U of the concrete structure 100. There is.

The concrete structure 100 may or may contain chloride ions in the internal region 100i depending on the installation environment, application, and the like, and the concentration distribution thereof is biased. In the concrete structure 100 of the present embodiment, the chloride ion concentration in the region where the second steel materials 4, 5, 6, 12, 13, 14, 15, and 16 are embedded in the concrete structure 100 is the first. The steel materials 1, 2, 3, 7, 8, 9, 10, 11 are higher or may be higher than the chloride ion concentration in the embedded region. That is, the area in which the second steel material 4,5,6,12,13,14,15,16 is buried in the concrete structure 100 and the first steel material 1,2,3,7,8,9,10 The corrosive environment is different from the area where, 11 is buried, or may change over time.

In the electrolytic corrosion protection method of the present embodiment, as shown in FIG. 1 (b), a plurality of linear anode materials 211a so as to extend in the longitudinal direction along the bottom surface 100B of the concrete structure 100 shown in FIG. 1 (a). , 211b, 211c are provided with a linear anode material installation step. The plurality of linear anode materials 211a, 211b, 211c may be installed along the bottom surface 100B of the concrete structure 100 in the band width direction as shown in the drawing, or the band width direction may be installed along the bottom surface 100B of the concrete structure 100. It may be installed along the thickness direction from 100U to the bottom surface 100B. To install the linear anode materials 211a, 211b, 211c, cut with a cutter or the like to form a plurality of elongated grooves on the bottom surface 100B, and insert each of the linear anode materials 211a, 211b, 211c inside each of the elongated grooves. , It can be carried out by filling and solidifying a filler containing a cement-based solidifying material in the long groove. In this case, in order to prevent the linear anode materials 211a, 211b, 211c from falling or misaligning from the concrete structure 100, the linear anode materials 211a, 211b, 211c are temporarily fixed in each elongated groove using a fixture. After that, the filler may be filled. Further, the linear anode materials 211a, 211b, 211c may be installed by directly fixing the linear anode materials 211a, 211b, 211c to the bottom surface 100B of the concrete structure 100 with a fixture.

The plurality of linear anode materials 211a, 211b, 211c are installed so that the longitudinal direction is along the longitudinal direction of the first steel materials 1, 2, and 3 of the concrete structure 100. The depth of the long groove is formed so that the distance from the bottom surface 100B of the concrete structure 100 to the bottom of the long groove is deeper than the thickness of the linear anode materials 211a to 211c. For example, since the concrete cover thickness with respect to the reinforcing bar is usually about 30 mm, the depth from the bottom surface 100B of the concrete structure 100 to the bottom of the long groove is about 15 mm or more and 25 mm or less.

As shown in FIG. 2B, the linear anode materials 211a, 211b, 211c are elongated strips whose surface is at least formed of a metal or a metal compound. Known examples of the linear anode materials 211a, 211b, 211c include a metal ribbon mesh anode material formed of an insoluble metal such as titanium, a metal grit type anode material, a metal tray type anode material, and a nickel-coated carbon fiber type anode material. An elongated strip-shaped anode material can be used.

In the electrolytic corrosion protection method of the present embodiment, as shown in FIG. 1 (c), a plurality of rod-shaped anode materials 231a to 231p are installed on the concrete structure 100 so as to extend in the longitudinal direction from the outer surface 100S toward the inner region 100i. It is provided with a rod-shaped anode material installation process. The rod-shaped anode materials 231a to 231p may be installed by drilling holes in the outer surface 100S of the concrete structure 100 to form insertion holes, and inserting the rod-shaped anode materials 231a to 231p into each of the insertion holes. In the examples shown in FIGS. 3 to 5, the concrete structure 100 is perforated from the bottom surface 100B, and is formed at a depth from the bottom surface 100B to the vicinity of the top surface 100U so that the insertion hole does not penetrate. The rod-shaped anode materials 231a to 231p are filled with a filler containing a cement-based solidifying material in the insertion hole at least before and after the rod-shaped anode materials 231a to 231p are inserted, and the rod-shaped anode materials 231a to 231p are inserted. By solidifying the filler in the state of being in the state, it can be fixed in the insertion hole.

Here, in the linear anode materials 211a, 211b, 211c and the rod-shaped anode materials 231a to 231p, the sum of the surface areas of the plurality of rod-shaped anode materials 231a to 231p in the concrete structure 100 is the sum of the surface areas of the plurality of linear anode materials 211a, 211b, Install so that it is equal to or greater than the sum of the surface areas of 211c. This makes it easier to supply the anticorrosion current to the second steel materials 4, 5, 6, 12, 13, 14, 15, and 16 far from the target surface. Therefore, in the electrocorrosion protection method of the present embodiment, the electrocorrosion protection can be performed so that the variation in the electrocorrosion protection effect between the steel materials is reduced. Further, in the concrete structure 300 according to the embodiment, the variation in the electric corrosion protection effect between the steel materials is further reduced in response to the difference in the corrosive environment such as the bias of the chloride ion concentration distribution in the concrete structure 300. Electrocorrosion protection can be performed. Further, the electrocorrosion protection method of the present embodiment can reduce the possibility of occurrence of a steel material whose polarization amount does not reach the anticorrosion reference value. If the amount of polarization reaches the anticorrosion reference value, it is determined that the reinforcing bar is in the anticorrosion state. _{The amount of polarization (ΔE) is the natural potential (Ecor} ) when the anticorrosion current is not passed and the anticorrosion current when the anticorrosion current is passed by the reference electrode installed near each of the steel materials 1 to 19 in the concrete structure 100. _{It is obtained as the amount of potential change from the instant off potential (Eins} ) immediately after the energization of the concrete is stopped, and if the polarization amount is equal to or more than the anticorrosion reference value (100 mV), each steel material 1 to 19 is in an anticorrosion state. It is judged.

In the present invention, the surface area of the linear anode materials 211a, 211b, 211c means the surface area of one main surface 212 of the linear anode materials 211a, 211b, 211c shaded in FIG. 2 (b). The surface area of the rod-shaped anode materials 231a to 231p refers to the area of the outer surface 232 of the rod-shaped anode materials 231a to 231p shaded in FIG. 2 (a). However, the surface areas of the linear anode materials 211a, 211b, 211c and the surface areas of the rod-shaped anode materials 231a to 231p are the surface areas of the portion that functions as the anode material, and when the portion that does not function as the anode material exists on the outer surface. , The surface area of the portion that does not function as the anode material is excluded. For example, the portion that does not function as the anode material is an opening or a void provided on the surface of the anode material.

As shown in FIG. 2, the rod-shaped anode materials 231a to 231p are fixed by winding an elongated strip-shaped body made of the same anode material as the linear anode materials 211a, 211b, 211c around the rod-shaped body. May be used. According to this, the area ratio of the surface areas of the linear anode materials 211a, 211b, 211c and the rod-shaped anode materials 231a to 231p can be accurately measured, and the variation in the current density of the anticorrosion current between the steel materials and the amount of polarization are anticorrosion. It is possible to further reduce the possibility of occurrence of steel materials that do not reach the standard value.

The plurality of rod-shaped anode materials 231a to 231p can be installed in the concrete structure 100 in an arbitrary arrangement. For example, as shown in FIG. 3, the plurality of rod-shaped anode materials 231a to 231p may be arranged in a staggered manner in the cross section of the concrete structure 100 that crosses the plurality of rod-shaped anode materials 231a to 231p. In this case, in the side view of the concrete structure 100 shown in FIGS. 4 and 5, the adjacent rod-shaped anode materials 231a to 231p are arranged so as not to overlap each other. As a result, the anticorrosion current can be more uniformly supplied from the plurality of rod-shaped anode materials 231a to 231p to the second steel materials 4, 5, 6, 12, 13, 14, 15, and 16. Therefore, it is possible to further reduce the possibility that the variation in the current density of the anticorrosion current between the steel materials and the amount of polarization of the anticorrosion current do not reach the anticorrosion reference value.

Further, as shown in FIGS. 6 to 8, the plurality of rod-shaped anode materials 231a to 231p are the adjacent rod-shaped anode materials 231a to 231p in the cross section of the concrete structure 100 that crosses the plurality of rod-shaped anode materials 231a to 231p. The virtual lines connecting the ends may be arranged in a grid pattern. In this case, in the side view of the concrete structure 100 shown in FIGS. 7 and 8, adjacent rod-shaped anode materials 231a to 231p are arranged in an overlapping manner. In FIGS. 6 to 8, the first external power supply X and the second external power supply Y are not shown.

In the rod-shaped anode material installation step, the insertion hole may be perforated in the target surface so as not to penetrate the concrete structure 100. In this case, the plurality of insertion holes can be formed in a region sandwiched between the plurality of linear anode materials 211a, 211b, 211c on the target surface. Therefore, as shown in FIGS. 3 to 8, the rod-shaped anode materials 231a to 231p are inserted from the bottom surface 100B toward the top surface 100U, and the ends of the rod-shaped anode materials 231a to 231p on the bottom surface 100B side are a plurality of lines on the bottom surface 100B. The rod-shaped anode materials 231a to 231p are installed so as to be located in the region sandwiched between the shape anode materials 211a, 211b, 211c. That is, the rod-shaped anode materials 231a to 231p are installed so that the ends of the rod-shaped anode materials 231a to 231p on the target surface side are located in the region sandwiched between the plurality of linear anode materials 211a, 211b, 211c on the target surface. .. According to this, the target surface on which the anode material can be installed is limited, and since it is far from the target surface on which the anode material can be installed, it is difficult to supply an anticorrosive current, or anticorrosion to the second steel material side where the corrosive environment may be bad. The amount of current supplied can be increased.

Although not shown, the insertion hole may be drilled from the upper surface 100U toward the bottom surface 100B so as not to penetrate the concrete structure 100. In this case, the rod-shaped anode materials 231a to 231p are inserted from the upper surface 100U toward the bottom surface 100B. Further, although not shown, the insertion hole may be drilled in the side surface 100L so as not to penetrate the concrete structure 100. In this case, the rod-shaped anode materials 231a to 231p are inserted from one side surface toward the other side surface.

In the rod-shaped anode material installation step, the distance between the end portion on the inner region 100i side and the end portion on the outer surface 100S side in the longitudinal direction and the distance between the end portion on the inner region 100i side and the second steel material 12 is the end on the inner region side. The rod-shaped anode material 231a may be installed so as to be shorter than the distance between the portion and the first steel material 7. The same applies to the rod-shaped anode materials 231b to 231p as shown in the figure. According to this, it is possible to increase the supply amount of the anticorrosion current to the second steel materials 4, 5, 6, 12, 13, 14, 15, and 16.

As shown in FIG. 2A, the rod-shaped anode materials 231a to 231p are rod-shaped bodies having at least an outer surface 232 formed of a metal or a metal compound. The rod-shaped anode materials 231a to 231p include a metal ribbon mesh linear anode material formed of an insoluble metal such as titanium, a metal mesh rod-shaped anode material obtained by winding a metal mesh planar anode material around a rod-shaped body and fixing the rod-shaped anode material, or a metal. A rod-shaped anode material or the like can be used. In the internal region 100i, the rod-shaped anode materials 231a to 231p are embedded so as to be electrically separated from the linear anode materials 211a to 211c at intervals that do not cause a short circuit.

As shown in FIG. 1D, the electrocorrosion protection method of the present embodiment includes the first steel materials 1, 2, 3, 7, 8, 9, 10, 11 and a plurality of linear anode materials 211a, 211b, 211c. Is electrically connected to the first external power source X, and the second steel materials 4, 5, 6, 12, 13, 14, 15, 16 and the plurality of rod-shaped anode materials 231a to 231p are connected to the second external power source. A connection step of electrically connecting to Y is provided. Specifically, the electrical connection can be made by connecting using a conducting wire. In order to simplify the illustration, in FIG. 1D, only a part of the electrical connections are schematically shown, and the electrical connections of the other parts are omitted. The first external power source X and the second external power source Y supply a direct current to the steel materials 1 to 19. The first external power source X and the second external power source Y are the first steel materials 1, 2, 3, 7, 8, 9, 10, 11 and the second steel materials 4, 5, 6, 12, 13, As long as the currents can be supplied to 14, 15 and 16 with different amounts of anticorrosion currents, they may be formed separately or integrally formed. As a result, a plurality of linear anode materials 211a, 211b, 211c to the first steel materials 1, 2, 3, 7, 8, 9, 10 are provided by the first external power source X through the concrete of the concrete structure 100. , An anticorrosion current flows into the surface of 11. Similarly, the anticorrosion current flows from the plurality of rod-shaped anode materials 231a to 231p to the surfaces of the second steel materials 4, 5, 6, 12, 13, 14, 15, and 16 by the second external power source Y. In the electrolytic corrosion protection method of the present embodiment, after that, the first external power source X to the first steel materials 1, 2, 3, 7, 8, 9, 10, 11 and a plurality of linear anode materials 211a, 211b, 211c The anticorrosion current of the first anticorrosion current value is passed through the second external power source Y to the second steel materials 4, 5, 6, 12, 13, 14, 15, 16 and a plurality of rod-shaped anode materials 231a to 231p. The step of passing the anticorrosion current of the anticorrosion current value of 2 is included. The second anticorrosion current value may be larger than the first anticorrosion current value, and the first anticorrosion current value and the second anticorrosion current value may show the same value. When the second anticorrosion current value is larger than the first anticorrosion current value, the anticorrosion current is supplied to the second steel materials 4, 5, 6, 12, 13, 14, 15, 16 arranged in the back. Even if it is difficult, the surface of the second steel material 4,5,6,12,13,14,15,16 is covered with the first steel material 1,2,3,7,8,9,10,11. The anticorrosion current can flow in at the same current density as the surface, further suppresses the deterioration of the durability of the electrocorrosion protection device including the anode material, and the variation in the current density of the anticorrosion current between the steel materials and the amount of polarization are the anticorrosion standards. It is possible to further reduce the possibility of occurrence of steel materials that do not reach the value.

(Concrete structure)
Next, the concrete structure 300 according to the embodiment of the present invention will be described with reference to FIGS. 3 to 8. The concrete structure 300 is manufactured by carrying out the electrocorrosion protection method according to the above-described embodiment, and includes the concrete structure 100 and the electrocorrosion protection device. The concrete structure 100 includes an outer surface 100S including a bottom surface 100B, which is a target surface, and an inner region 100i surrounded by the outer surface 100S, and steel materials 1 to 19 are embedded in the inner region 100i. The steel materials 1 to 19 are the first steel material 1,2,3,7,8,9,10,11 and the second steel material 4,5,6,12,13,14,15,16. The distance between the second steel material 4,5,6,12,13,14,15,16 and the bottom surface 100B, which is the target surface, is the first steel material 1,2,3,7,8,9,10,11. The second steel materials 4, 5, 6, 12, 13, 14, 15, 16 which are arranged so as to be longer than the distance from the bottom surface 100B, which is the target surface, are arranged in multiple stages.

The concrete structure 300 according to the present embodiment further includes an electrocorrosion protection device installed in the concrete structure 100. The electrocorrosion device includes a plurality of linear anode materials 211a to 211c whose longitudinal direction extends along the target surface, and a plurality of rod-shaped anode materials 231a to 231p whose longitudinal direction extends from the outer surface 100S toward the inner region 100i. A first external power source X electrically connected to the steel materials 1, 2, 3, 7, 8, 9, 10, 11 and the plurality of linear anode materials 211a to 211c, and a second steel material 4 , 5, 6, 12, 13, 14, 15, 16 and a second external power supply Y electrically connected to the plurality of rod-shaped anode materials 231a to 231p. Although not shown, the electrocorrosion protection device may further include a reference electrode for controlling the amount of the corrosion protection current.

In the concrete structure 300, as described in the embodiment of the electrocorrosion protection method described above, the linear anode materials 211a to 211c and the rod-shaped anode materials 231a to 231p have a plurality of sums of the surface areas of the plurality of rod-shaped anode materials 231a to 231p. It is provided so as to be equal to or greater than the sum of the surface areas of the linear anode materials of.

With the above configuration, the concrete structure 300 according to the present embodiment can easily supply the anticorrosion current to the second steel materials 4, 5, 6, 12, 13, 14, 15, and 16 far from the target surface. Therefore, the electric corrosion protection can be performed so that the variation in the electric corrosion protection effect between the steel materials is further reduced. Further, in the concrete structure 300 according to the embodiment, the variation in the electric corrosion protection effect between the steel materials is further reduced in response to the difference in the corrosive environment such as the bias of the chloride ion concentration distribution in the concrete structure 300. Electrocorrosion protection can be performed. Further, the concrete structure 300 can be controlled so that the possibility that a steel material that does not reach the anticorrosion standard value is generated is low. Therefore, the concrete structure 300 of the present embodiment has high corrosion resistance of the steel material, and the concrete structure 300 itself has high durability.

As shown in FIG. 3, the plurality of rod-shaped anode materials 231a to 231p may be arranged in a staggered manner in a cross section crossing the plurality of rod-shaped anode materials 231a to 231p. As a result, the variation in the current density of the anticorrosion current between the steel materials and the possibility of occurrence of the steel material whose polarization amount does not reach the anticorrosion standard value can be further reduced, and the durability of the concrete structure 300 can be further improved. it can. Further, as shown in FIG. 6, the plurality of rod-shaped anode materials 231a to 231p are adjacent to each other when the concrete structure 100 is viewed from the side in a cross section crossing the plurality of rod-shaped anode materials 231a to 231p. ~ 231p may be arranged so as to overlap.

(Manufacturing method of concrete structure)
The method for manufacturing the concrete structure 300 according to the present embodiment is a method for manufacturing the concrete structure 300 by installing an electric corrosion protection device on the concrete structure 100 by implementing the electric corrosion protection method according to the above-described embodiment. is there. Specifically, a step of installing an electric corrosion protection device in the concrete structure 100 in which the steel materials 1 to 19 are embedded is provided. The concrete structure 100 includes an outer surface 100S including a bottom surface 100B which is a target surface and an inner region 100i surrounded by the outer surface 100S, and the first steel material 1, 2, 3, 7, 8 is included in the inner region 100i. , 9, 10 and 11 are buried, and the second steel materials 4, 5, 6, 12, 13, 14, 15 and 16 are buried in the internal area 100i.

The second steel material 4,5,6,12,13,14,15,16 is the distance between the second steel material 4,5,6,12,13,14,15,16 and the bottom surface 100B which is the target surface. Is arranged so as to be longer than the distance between the first steel materials 1, 2, 3, 7, 8, 9, 10, 11 and the bottom surface 100B, which is the target surface. That is, the second steel materials 4, 5, 6, 12, 13, 14, 15, and 16 are separated from the bottom surface 100B, which is the target surface, and are in positions where it is difficult to supply the anticorrosion current.

Next, a step of installing the anticorrosion device on the concrete structure 100 will be described. The steps of installing the anticorrosion device include the steps of installing a plurality of linear anode materials 211a to 211c so as to extend in the longitudinal direction along the bottom surface 100B, which is the target surface, and the outer surface of the concrete structure 100 in the longitudinal direction. A step of installing a plurality of rod-shaped anode materials 231a to 231p so as to extend from 100S toward the internal region 100i is provided.

The linear anode materials 211a to 211c and the rod-shaped anode materials 231a to 231p are installed so that the sum of the surface areas of the plurality of rod-shaped anode materials 231a to 231p is equal to or greater than the sum of the surface areas of the plurality of linear anode materials 211a to 211c. Further, in the step of installing the anticorrosion device on the concrete structure 100, the first steel materials 1, 2, 3, 7, 8, 9, 10, 11 and the plurality of linear anode materials 211a to 211c are connected to each other by conducting wires or the like. The second steel materials 4, 5, 6, 12, 13, 14, 15, 16 and the plurality of rod-shaped anode materials 231a to 231p are electrically connected to the first external power source X by means of a lead wire or the like. Includes the step of electrically connecting to the external power supply Y of the above.

With the above configuration, the method for manufacturing the concrete structure 300 according to the present embodiment can manufacture the concrete structure 300 having high durability.

As shown in FIG. 3, the plurality of rod-shaped anode materials 231a to 231p may be arranged in a staggered manner in a cross section crossing the plurality of rod-shaped anode materials 231a to 231p. As a result, the variation in the current density of the anticorrosion current between the steel materials and the possibility of occurrence of the steel material whose polarization amount does not reach the anticorrosion standard value can be further reduced, and the durability of the concrete structure 300 can be further improved. it can. Further, as shown in FIG. 6, the plurality of rod-shaped anode materials 231a to 231p are adjacent to each other when the concrete structure 100 is viewed from the side in a cross section crossing the plurality of rod-shaped anode materials 231a to 231p. ~ 231p may be arranged so as to overlap.

Hereinafter, the electrocorrosion protection method according to the above embodiment will be described in more detail with reference to Examples.

(Example 1)
The electrocorrosion protection method of Example 1 is a combination of a dotted anode method and a linear anode method arranged in a staggered pattern, and embodies the electrocorrosion protection method according to the embodiment shown in FIGS. 3 to 5. It's a thing. In Example 1, a reinforced concrete floor slab is used as the concrete structure 100, and a reinforcing bar is used as the steel material. Further, in the first embodiment, in order to indicate the position of each reinforcing bar, the reference numerals of the steel materials shown in FIGS. 3 to 5 will be cited and described.

The concrete floor slab is formed so that the thickness T from the top surface to the bottom surface is 200 mm and the bottom surface is 1230 mm × 600 mm. For concrete floor slabs, the lower reinforcing bars 1,2,3,7,8,9,10,11, which are the first steel materials, and the upper reinforcing bars 4,5,6,12,13,14, which are the second steel materials, are used. , 15 and 16 are buried. The upper reinforcing bars 4, 5, 6, 12, 13, 14, 15, 16 are composed of reinforcing bars 12, 13, 14, 15, 16 arranged at 250 mm intervals and reinforcing bars 4, 5, 6 arranged at 130 mm intervals. It is formed by intersecting in a grid pattern. Similarly, the lower reinforcing bars 1, 2, 3, 7, 8, 9, 10, 11 are the reinforcing bars 7, 8, 9, 10, 11 arranged at 250 mm intervals, and the reinforcing bars 1, 2 arranged at 130 mm intervals. , 3 intersect in a grid pattern. The upper reinforcing bars 4,5,6,12,13,14,15,16 have a distance of 35 mm from the upper surface of the concrete floor slab, and the lower reinforcing bars 1,2,3,7,8,9,10,11 have. It is arranged so that the distance from the bottom surface of the concrete floor slab is 35 mm.

As the lower reinforcing bars 1,2,3,7,8,9,10,11 and the upper reinforcing bars 4,5,6,12,13,14,15,16, the sheath tube φ40 (nominal major axis 19.1 mm, nominal) A reinforcing bar (D13 (JIS G 3112-1964)) inserted through a circumference of 60 mm) was used. The concrete floor board has the chloride ion concentration in the concrete in the area where the upper reinforcing bars 4, 5, 6, 12, 13, 14, 15, 16 are buried, based on the measured values in the bridge slab actually installed. However, the lower reinforcing bars 1, 2, 3, 7, 8, 9, 10, and 11 were formed so as to be higher than the chloride ion concentration in the concrete in the buried area. Specifically, in the concrete floor board, calcium chloride is 5 kg / m ³ with ^{respect to concrete 1 m 3} (excluding calcium chloride) in the arrangement area of the upper reinforcing bars 4, 5, 6, 12, 13, 14, 15, 16. ^{Concrete formed by kneading so as to be poured is poured, and calcium chloride is added to 1 m 3} of concrete (excluding calcium chloride) in the arrangement area of the lower reinforcing bars 1, 2, 3, 7, 8, 9, 10, 11. ^{The concrete formed by kneading to 3} kg / m 3 was poured and then hardened.

Next, three titanium ribbon mesh linear anode materials were installed on the concrete slab so that the longitudinal direction was along the bottom surface of the concrete slab. More specifically, the bottom surface of the concrete slab is cut, and a long groove along the longitudinal direction of the reinforcing bar 1 at a distance of 100 mm from the side edge of the concrete slab and a long groove 2 at a distance of 200 mm from the long groove. , 3 long grooves along the longitudinal direction, and a total of 3 long grooves were formed. An elongated strip-shaped linear anode material is inserted into the elongated groove and temporarily fixed to the bottom of the elongated groove, and then cement mortar is filled in the groove as a filler to embed the anode for electrolytic corrosion protection in the concrete floor slab. And repaired the groove. As a result, three titanium ribbon mesh linear anode materials were installed on the bottom surface of the concrete floor slab at intervals of 200 mm as the linear anode materials of the present embodiment.

Next, the titanium ribbon mesh rod-shaped anode material was installed on the concrete slab so that the longitudinal direction extended from the bottom surface toward the internal region. More specifically, first, a hole was made in the bottom surface of the concrete slab to provide a plurality of insertion holes in the concrete slab. The perforations in the concrete slab were made so that a plurality of insertion holes were arranged in a staggered pattern on the bottom surface of the concrete slab as shown in FIG. After inserting the rod-shaped anode material into the insertion hole, the insertion hole was embedded with the filler. As the rod-shaped anode material, a titanium ribbon mesh rod-shaped anode material in which the same titanium ribbon mesh anode material as the above-mentioned linear anode material was wound around a columnar body was formed and used.

As a result, the titanium ribbon mesh rod-shaped anode materials were arranged in a staggered manner so that the distance between the adjacent titanium ribbon mesh rod-shaped anode materials 231a to 231p was 100 mm or more and 130 mm or less in the cross section passing through the titanium ribbon mesh rod-shaped anode material. As a result, each titanium ribbon mesh rod-shaped anode material has an end portion on the inner region side of the titanium ribbon mesh rod-shaped anode material and the upper reinforcing bar 4,5,6,12,13,14,15,16 closest to the end portion. The distance from any of the titanium ribbon mesh rod-shaped anode materials is between the end of the titanium ribbon mesh rod-shaped anode material on the inner region side and one of the lower reinforcing bars 1, 2, 3, 7, 8, 9, 10, and 11 closest to the end. It was installed so that it was shorter than the distance.

The titanium ribbon mesh linear anode material and the titanium ribbon mesh rod-shaped anode material are installed so that the sum of the surface areas of the plurality of titanium ribbon mesh rod-shaped anode materials is equal to or greater than the sum of the surface areas of the plurality of titanium ribbon mesh linear anode materials. It was. In this example, the sum of the surface areas of the three titanium ribbon mesh linear anode materials and the sum of the surface areas of the 16 titanium ribbon mesh rod-shaped anode materials were set to be 1.00: 1.08.

Then, the lower reinforcing bars 1, 2, 3, 7, 8, 9, 10, 11 and the titanium ribbon mesh linear anode material are electrically connected to the first external power source X by lead wires, and the upper reinforcing bars 4 are connected. , 5, 6, 12, 13, 14, 15, 16 and titanium ribbon mesh rod-shaped anode materials 231a to 231p are electrically connected to a second external power supply Y different from the first external power supply X by a lead wire. did. As a result, a concrete floor slab with an electric anticorrosion device according to the electrocorrosion protection method according to Example 1 was formed. An anticorrosion current of 3.7 mA was passed from a first external power source and a second external power source to the concrete floor slab with an electrocorrosion device to perform electrocorrosion protection.

(Example 2)
The electrolytic corrosion protection method of the second embodiment uses both a point-shaped anode method and a linear anode method in which a plurality of adjacent rod-shaped anode materials are arranged so as to overlap each other in a side view of the concrete structure. It embodies the electrocorrosion protection method according to the embodiment shown in FIGS. 4 to 6. Since the electrocorrosion protection method of Example 2 differs from the electrocorrosion protection method of Example 1 only in the arrangement pattern of the rod-shaped anode material and the insertion hole, only these arrangement patterns will be described, and the description of Example 1 is quoted for others. To do. In Example 2, in order to indicate the position of each reinforcing bar, the reference numerals of the steel materials shown in FIGS. 6 to 8 are cited and described.

In the anticorrosion method of Example 2, a plurality of insertion holes are arranged in a row on the bottom surface of the concrete floor slab as shown in FIG. Then, after inserting the titanium ribbon mesh rod-shaped anode material into the insertion hole, the insertion hole was embedded with the filler. As a result, the titanium ribbon mesh rod-shaped anode material has the adjacent rod-shaped anode materials 231a to 130 mm or less so that the distance between the adjacent titanium ribbon mesh rod-shaped anode materials is 100 mm or more and 130 mm or less in the cross section passing through the titanium ribbon mesh rod-shaped anode material. The virtual lines connecting the ends of 231p were arranged in a grid pattern, and a plurality of adjacent rod-shaped anode materials were arranged so as to overlap each other in the side view of the concrete structure. Except for this, the electrocorrosion protection method was carried out in the same manner as in Example 1, and a concrete floor slab with an electrocorrosion protection device was formed by the electrocorrosion protection method according to Example 2. An anticorrosion current of 3.7 mA was passed from a first external power source and a second external power source to the concrete floor slab with an electrocorrosion device to perform electrocorrosion protection.

(Comparative Example 1)
In the electrocorrosion protection method of Comparative Example 1, one external power source (first) is used, whereas the electrocorrosion protection methods of Examples 1 and 2 are provided with a plurality of external power sources to form a plurality of electrocorrosion circuits. It differs in that it is provided with only the external power supply X) to form one electric corrosion protection circuit. Specifically, in the electrolytic corrosion protection method of Comparative Example 1, the lower reinforcing bars 1, 2, 3, 7, 8, 9, 10, 11 and the titanium ribbon mesh linear anode material and the upper reinforcing bars 4, 5, 6 are used. , 12, 13, 14, 15, 16 and titanium ribbon mesh rod-shaped anode materials 231a to 231p were electrically connected to the same first external power source X by lead wires. Except for this, the electrocorrosion protection method was carried out in the same manner as in Example 1, and a concrete floor slab with an electrocorrosion protection device was formed by the electrocorrosion protection method according to Comparative Example 1. An anticorrosion current of 3.7 mA was passed through the concrete floor slab with an electrocorrosion device from the first external power source to perform electrocorrosion protection.

(Comparative Example 2)
In the electrocorrosion protection method of Comparative Example 2, the sum of the surface areas of the plurality of titanium ribbon mesh rod-shaped anode materials is equal to or greater than the sum of the surface areas of the plurality of titanium ribbon mesh linear anode materials in the electrocorrosion protection methods of Examples 1 and 2. Whereas it was installed, it was installed so that the sum of the surface areas of the plurality of titanium ribbon mesh rod-shaped anode materials was less than the sum of the surface areas of the plurality of titanium ribbon mesh linear anode materials.

In the electrolytic corrosion protection method of Comparative Example 2, the lower reinforcing bars 1, 2, 3, 7, 8, 9, 10, 11 and all the titanium ribbon mesh linear anode materials are connected to the first external power supply X by lead wires. Electrically connected to the upper reinforcing bars 4, 5, 6, 12, 13, 14, 15, 16 and 8 titanium ribbon mesh rod-shaped anode materials out of the 16 installed titanium ribbon mesh rod-shaped anode materials. Was electrically connected to a second external power supply Y separate from the first external power supply X by a lead wire. That is, the remaining eight titanium ribbon mesh rod-shaped anode materials were not energized on a trial basis and were not electrically connected. As a result, the sum of the surface areas of the three titanium ribbon mesh linear anode materials and the sum of the surface areas of the eight titanium ribbon mesh rod-shaped anode materials has an area ratio of 1.00: 0.54. Except for the above, the electrocorrosion protection method was carried out in the same manner as in Example 1 to form a concrete floor slab with an electrocorrosion protection device by the electrocorrosion protection method according to Comparative Example 2. An anticorrosion current of 3.7 mA was passed from a first external power source and a second external power source to the concrete floor slab with an electrocorrosion device to perform electrocorrosion protection.

(Comparative Example 3)
In the electrocorrosion protection method of Comparative Example 3, the amount of current flowing from the second external power source is larger than the amount of current flowing from the first external power source in the electrocorrosion protection method of Comparative Example 2. Corrosion protection is applied to the concrete floor slab with an electric corrosion protection device shown in Comparative Example 2 by setting the current amount of the corrosion protection current flowing from the first external power source to 3.7 mA and the current amount of the corrosion protection current flowing from the second external power source to 5.55 mA. It is the one that supplied the electric current. As a result, the amount of the anticorrosion current flowing from the second external power source is 1.5 times the amount of the anticorrosion current flowing from the first external power source.

(Current density per reinforcing bar surface area)
The current densities per reinforcing bar surface area of the reinforcing bars 1 to 19 were measured for the concrete slab with the electric corrosion protection device formed by the electric corrosion protection method according to Examples 1 and 2 and Comparative Examples 1 to 3. In Examples 1 and 2 and Comparative Examples 1 to 3, in order to measure the current density per the surface area of the reinforcing bars 1 to 19, the upper reinforcing bars 4, 5, 6, 12, 13, 14, 15, 16 and the lower reinforcing bars are used. Reinforcing bars 1, 2, 3, 7, 8, 9, 10, 11 and laterally tightened steel materials 17, 18, 19 were prevented from electrically conducting inside the concrete structure. The current density per reinforcing bar surface area of the reinforcing bars 1 to 19 was derived by inserting a 1Ω resistor between each reinforcing bar 1 to 19 and the power supply device and measuring the voltage in the resistor using a voltmeter. The derivation was performed by calculating the amount of current using the formula of current (A) = voltage (V) / resistance (Ω) and then dividing the calculated amount of current by the surface area of each reinforcing bar. The results are shown in FIGS. 9 to 13. In FIGS. 9 to 13, the horizontal axis represents each reinforcing bar 1 to 19, and the vertical axis represents the current density (mA / m ² ) per reinforcing bar surface area.

(Amount of polarization)
With respect to the concrete floor slab with the electric corrosion protection device formed by the electric corrosion protection method according to Examples 1 and 2 and Comparative Examples 1 to 3, the polarization amounts of the lower reinforcing bar 7 and the upper reinforcing bar 12 were measured using a lead reference electrode. The measured amount of polarization is shown in Table 1.

(result)
FIG. 9 is a graph showing the current density per the surface area of the reinforcing bars 1 to 19 for the concrete floor slab with the electric corrosion protection device formed by the electric corrosion protection method according to the first embodiment. Further, FIG. 10 is a graph showing the current densities per the surface area of the reinforcing bars 1 to 19 for the concrete floor slab with the electric corrosion protection device formed by the electric corrosion protection method according to the second embodiment. Similarly, FIG. 11 shows Comparative Example 1, FIG. 12 shows Comparative Example 2, and FIG. 13 shows the concrete slab with an electric corrosion protection device formed by the electric corrosion protection method according to Comparative Example 3 per the surface area of the reinforcing bars 1 to 19. It is a graph which shows the current density.

As shown in FIGS. 9 and 10, as compared with Comparative Example 1, the concrete floor slab with the electric corrosion protection device formed by the electric corrosion protection method according to Examples 1 and 2 has the current density of the corrosion protection current of the reinforcing bars 1 to 19. The variation is small. The concrete floor slab with an electric anticorrosion device formed by the electrocorrosion protection method according to the first embodiment has a polarization amount of 75 mV for the upper reinforcing bar and does not satisfy the anticorrosion standard value of 100 mV, but the anticorrosion current flowing from the second external power source. It is recognized that the electric corrosion protection method can be carried out without significantly reducing the durability of the electric corrosion protection device including each anode material, which can be dealt with by passing a slightly large amount of current. Therefore, in the electrocorrosion protection method according to Examples 1 and 2, the variation in the current density of the anticorrosion current between the steel materials and the amount of polarization become the anticorrosion reference values without significantly reducing the durability of the electrocorrosion protection device including each anode material. It was possible to reduce the possibility of occurrence of steel materials that did not reach.

Further, when comparing Example 1 and Example 2, the one in which a plurality of rod-shaped anode materials are arranged in a staggered pattern as in Example 1 is adjacent to each other in the side view of the concrete structure as in Example 2. The variation in the current densities of the reinforcing bars 1 to 19 could be made smaller than that in which a plurality of combined rod-shaped anode materials were arranged so as to overlap each other.

On the other hand, as shown in FIG. 11, in the concrete floor slab with an electric corrosion protection device formed by the electric corrosion protection method according to Comparative Example 1, the corrosion protection currents are applied to the lower reinforcing bars 1, 2, 3, 7, 8, 9, and 10. Concentrated, the upper reinforcing bars 4, 5, 6, 12, 13, 14, 15, and 16 had a current density of about 30 to 50% of that of the lower reinforcing bar 1, etc., and caused a large variation. Further, as shown in Table 1, the amount of polarization of the upper reinforcing bar was 25 mV, which resulted in a significant lack of corrosion protection, and metal corrosion protection could not be performed satisfactorily.

As shown in FIG. 12, the concrete floor slab with an electrocorrosion device formed by the electrocorrosion protection method according to Comparative Example 2 also has a large variation in the current densities of the reinforcing bars 1 to 19, and the polarization amount of the upper reinforcing bar is too low. Metal corrosion protection could not be performed well. Therefore, as in Comparative Example 3, it is conceivable to increase the current value of the anticorrosion current supplied from the second external power source. Although the anticorrosion current reference value is satisfied as shown in Table 1, FIG. 13 As shown in the above, it was expected that the overcorrosion state of the reinforcing bars 4 to 6 and the reinforcing bars 13 to 16 would become large, which would impose a burden on the electric corrosion protection device including the anode material, and the durability of the anode material would be reduced to about 75%. ..

From the above, in the electrocorrosion protection method according to the present embodiment, the variation in the current density of the anticorrosion current between the steel materials and the amount of polarization do not reach the anticorrosion standard value without significantly reducing the durability of the electrocorrosion protection device including the anode material. It was possible to further reduce the possibility of steel material generation.

The electrolytic corrosion protection method according to the present invention is not limited to the above-described embodiment and the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. Further, the configurations and methods of the plurality of embodiments described above may be arbitrarily adopted and combined, and further, the configurations and methods and the like according to the various modified examples described below may be arbitrarily selected to form the above-described embodiments. Of course, it may be adopted for such a configuration or method.

For example, in the above-described embodiment and the above-described embodiment, the bottom surface 100B of the concrete structure 100 has been used as the target surface, but the top surface 100U and the side surface 100L of the concrete structure 100, or a plurality of combinations thereof are used as the target surface. May be good. Which surface is to be the target surface is selected according to the type of the concrete structure 100, the corrosive environment in the concrete structure 100, and the like. For example, when the concrete structure 100 is a columnar structure or a beam-shaped structure, the side surface of the columnar structure or the beam-shaped structure can be the target surface, and when the concrete structure 100 is a reinforced concrete house, the side surface can be the target surface. The upper surface and wall surface of the roofing material can be the target surface.

Further, in the above-described embodiment and the above-described embodiment, it is described that the step of installing the rod-shaped anode material is included after the step of installing the linear anode material, but in the present invention, each step may be included in no particular order. It can be done, or a plurality of steps can be performed at the same time. For example, the linear anode material installation step is arranged after the rod-shaped anode material installation process, or the rod-shaped anode material installation step is performed after the first and second external power supplies are connected to the rod-shaped anode material and the linear anode material in advance. Needless to say, the step of installing the linear anode material may be included.

1 to 19 ... Steel material 100 ... Concrete structure 100B ... Bottom surface 100i ... Internal area 100S ... Outer surface 100U ... Top surfaces 211a to 211c ... Linear anode material 231a to 231p ... Rod-shaped anode material 212 ... One main surface of linear anode material 232 ... Outer surface 300 of rod-shaped anode material ... Concrete structure X ... First external power supply Y ... Second external power supply

Claims (6)

A concrete structure in which a steel material is embedded, the outer surface including the target surface, the inner region surrounded by the outer surface, the first steel material buried in the inner region, and the first steel material buried in the inner region. A second steel material, which is arranged so that the distance between the second steel material and the target surface is longer than the distance between the first steel material and the target surface. A linear anode material installation step of installing a plurality of linear anode materials so as to extend in the longitudinal direction along the target surface on the concrete structure to be provided.
A rod-shaped anode material installation step of installing a plurality of rod-shaped anode materials on the concrete structure so that the longitudinal direction extends from the outer surface toward the inner region.
It is an electric anticorrosion method equipped with
The first steel material and the plurality of linear anode materials are electrically connected to a first external power source, and the second steel material and the plurality of rod-shaped anode materials are connected to a second external power source. The linear anode material and the rod-shaped anode material are installed so that the sum of the surface areas of the plurality of rod-shaped anode materials is equal to or greater than the sum of the surface areas of the plurality of linear anode materials. Electrocorrosion protection method. The rod-shaped anode material installation step includes a step of forming the plurality of insertion holes in the target surface in a region sandwiched between the plurality of linear anode materials, and a step of inserting the rod-shaped anode material into the insertion holes. The electrocorrosion protection method according to claim 1, which comprises. In the rod-shaped anode material installation step, the distance between the end portion on the inner region side and the end portion on the outer surface side and the distance between the end portion on the inner region side and the second steel material is the end portion on the inner region side. The electrocorrosion protection method according to claim 1 or 2, wherein the rod-shaped anode material is installed so as to be shorter than the distance between the first steel material and the first steel material. Any one of claims 1 to 3 in which the rod-shaped anode material is installed so that the plurality of rod-shaped anode materials are arranged in a staggered manner in a cross section crossing the plurality of rod-shaped anode materials in the rod-shaped anode material installation step. The electrocorrosion protection method described in. It is a concrete structure in which steel materials are buried.
The outer surface including the target surface and
The internal area surrounded by the outer surface and
The first steel material buried in the internal region and
A second steel material embedded in the internal region, which is arranged so that the distance between the second steel material and the target surface is longer than the distance between the first steel material and the target surface. 2 steel materials and
A plurality of linear anode materials whose longitudinal directions extend along the target surface,
A plurality of rod-shaped anode materials whose longitudinal direction extends from the outer surface toward the inner region,
A first external power source that is electrically connected to the first steel material and the plurality of linear anode materials,
A second external power source that is electrically connected to the second steel material and the plurality of rod-shaped anode materials is provided.
The linear anode material and the rod-shaped anode material are concrete structures provided so that the sum of the surface areas of the plurality of rod-shaped anode materials is equal to or greater than the sum of the surface areas of the plurality of linear anode materials. A concrete structure in which a steel material is embedded, the outer surface including the target surface, the inner region surrounded by the outer surface, the first steel material buried in the inner region, and the first steel material buried in the inner region. A second steel material, which is arranged so that the distance between the second steel material and the target surface is longer than the distance between the first steel material and the target surface. A linear anode material installation step of installing a plurality of linear anode materials so as to extend in the longitudinal direction along the target surface on the concrete structure to be provided.
A rod-shaped anode material installation step of installing a plurality of rod-shaped anode materials on the concrete structure so that the longitudinal direction extends from the outer surface toward the inner region.
It is a manufacturing method of a concrete structure provided with
The first steel material and the plurality of linear anode materials are electrically connected to a first external power source.
The second steel material and the plurality of rod-shaped anode materials are electrically connected to a second external power source.
A method for manufacturing a concrete structure in which the linear anode material and the rod-shaped anode material are installed so that the sum of the surface areas of the plurality of rod-shaped anode materials is equal to or greater than the sum of the surface areas of the plurality of linear anode materials.

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