JP5418407B2 - Construction method for concrete structures - Google Patents

Description

 The present invention relates to a method for constructing a concrete structure.

  As shown in FIG. 2, a conventional concrete structure construction method includes an MMO (Mixed Metal Oxide) anode electrode 2 for cathodic protection on the discarded concrete 1 before placing the foundation slab concrete. A construction method is known in which a slab rebar 4 is assembled on the top, and after confirming that there is no electrical short circuit between the slab rebar 4 and the MMO anode electrode 2, a foundation slab concrete is placed. .

  The general MMO anode electrode 2 is often formed into a thin plate by weaving MMO fine wires mainly composed of non-consumable metal such as titanium into a mesh shape. In the anticorrosion, a positive voltage is applied to the MMO anode electrode 2 and a negative voltage is applied to the slab rebar 4 to generate a potential difference between the MMO anode electrode 2 and the slab rebar 4. This is a technique for preventing the slab rebar 4 from being corroded.

  The distance (gap) between the MMO anode electrode 2 and the slab reinforcing bar 4 can be theoretically derived according to the potential difference generated between the two and the components of the concrete. The slab rebar 4 is assembled at a predetermined position on the MMO anode electrode 2 with the target gap as a target. At this time, as shown in FIG. 2, an electrical short circuit between the slab reinforcing bar 4 and the MMO anode electrode 2 occurs only by the contact of the wire 5 that binds the slab reinforcing bars 4 to the MMO anode electrode 2. Since much labor and time are spent identifying the cause, it is necessary to pay close attention to assembling the slab rebar 4.

  On the other hand, for example, in Patent Document 1 below, a non-consumable electrode mainly composed of titanium is coated with mortar or concrete to form a square bar, and an end portion of the non-consumable electrode is formed on a longitudinal end surface of the square bar. A technique for preventing an electrical short circuit between a reinforcing bar and a non-consumable electrode by manufacturing an anode electrode body provided with a connecting piece with exposed metal and using the anode electrode body as an electrode for cathodic protection is disclosed. .

JP 2003-213804 A

  In the technique of the above-mentioned Patent Document 1, it is necessary to form a square bar of a predetermined size by previously covering a non-consumable electrode with mortar or concrete, so that the size can be changed flexibly according to the situation of each construction site. It is difficult to make design changes.

 The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a method for constructing a concrete structure capable of easily realizing prevention of an electrical short circuit between an electrode for anticorrosion and a reinforcing bar. And

In order to solve the above-described problems, in the present invention, as a first solving means related to a concrete structure construction method, a first step of laying an electrode for cathodic protection on lower-layer side concrete, and on the lower-layer side concrete A second step of placing protective concrete so as to cover the electrode for anticorrosion, a third step of assembling a reinforcing bar after placing the protective concrete, and placing an upper-layer side concrete after assembling the reinforcing bar. And a fourth step to be provided.
In the present invention, as the second solving means relating to the construction method of the concrete structure, in the first solving means, the lower layer side concrete is discarded concrete, the reinforcing bar is a slab reinforcing bar, and the upper layer side The concrete is basic slab concrete.
Further, in the present invention, as a third solving means relating to a method for constructing a concrete structure, in the first or second solving means, the electrode for anticorrosion is made of a composite metal oxide containing titanium as a main component. It is configured.

 In the present invention, before assembling the reinforcing bars, the protective concrete is placed so as to cover the anticorrosive electrodes laid on the lower concrete layer, thereby preventing an electrical short circuit between the anticorrosive electrodes and the reinforcing bars. can do. That is, according to the present invention, it is only necessary to add a simple process called a protective concrete placing process to the construction process, and it is necessary to use a square bar with an electrode or the like that is difficult to change in design as in Patent Document 1 above. Therefore, it is possible to easily realize prevention of electrical short circuit between the electrode for anticorrosion and the reinforcing bar.

It is a schematic diagram showing each process of the construction method of the concrete structure in this embodiment. It is a schematic diagram showing the construction method of the conventional concrete structure.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Drawing 1 is a mimetic diagram showing each process of a construction method of a concrete structure in this embodiment. In FIG. 1, parts that are the same as those in FIG. First, as a first step in the method for constructing a concrete structure, as shown in FIG. 1 (a), an MMO anode electrode 2 as an electrode for anticorrosion is disposed on abandoned concrete 1 previously placed as lower-layer side concrete. Lay down.

  As the MMO anode electrode 2, an MMO thin wire mainly composed of a non-consumable metal such as titanium or the like formed by weaving it in a mesh shape may be used, or an MMO itself formed in a thin plate shape may be used. May be used. In addition, as a metal material that can be used as an electrode for cathodic protection, not only MMO mainly composed of non-consumable metals such as titanium, but also nickel or lead as long as the natural potential is higher than the reinforcing bar (iron) that is to be protected. , Tin, copper, silver, gold, platinum and the like and alloy materials thereof can be used.

  Subsequently, as a second step in the method for constructing the concrete structure, as shown in FIG. 1B, the protective concrete 3 is placed on the discarded concrete 1 so as to cover the MMO anode electrode 2. As described above, the slab reinforcing bar 4 is assembled at a predetermined position on the MMO anode electrode 2 with the goal of the distance (gap) between the MMO anode electrode 2 and the slab reinforcing bar 4 described later theoretically obtained in advance. Therefore, it is necessary to appropriately set the thickness of the protective concrete 3 while considering the gap. In addition, when the thickness of the protective concrete 3 is too thin, there is a possibility that a later-described number wire 5 may pass through the protective concrete 3 and come into contact with the MMO anode electrode 2, so the thickness may be set to at least 30 mm or more. preferable.

  Subsequently, as a third step in the construction method of the concrete structure, as shown in FIG. 1 (c), after placing the protective concrete 3, the MMO anode is targeted for the theoretically obtained gap. The slab rebar 4 is assembled at a predetermined position on the electrode 2. At this time, as shown in FIG. 1C, the slab reinforcing bars 4 are bound together by the number wire 5, but since the MMO anode electrode 2 is covered with the protective concrete 3, the number wire 5 is the MMO anode electrode. 2, that is, it is possible to reliably prevent the slab rebar 4 and the MMO anode electrode 2 from being electrically short-circuited.

  Subsequently, as a fourth step in the concrete structure construction method, as shown in FIG. 1 (d), after the slab rebar 4 is assembled, the foundation slab concrete 6 is placed as the upper-layer side concrete. Thus, by placing the protective concrete 3 before placing the foundation slab concrete 6, it is possible to completely eliminate the risk of an electrical short circuit between the slab rebar 4 and the MMO anode electrode 2. The remaining construction can be continued at the planned cost and process.

 As described above, in the present embodiment, before assembling the slab reinforcing bar 4, the protective concrete 3 is placed so as to cover the MMO anode electrode 2 laid on the discarded concrete 1. And slab rebar 4 can be prevented from being electrically short-circuited. In other words, according to the present embodiment, it is only necessary to add a simple process of placing the protective concrete 3 to the construction process, and the use of a square bar with electrodes that is difficult to change the design as in Patent Document 1 above. Therefore, it is possible to easily prevent the electrical short circuit between the MMO anode electrode 2 and the slab rebar 4.

  In the above embodiment, the protective concrete 3 is placed so as to cover the MMO anode electrode 2 laid on the discarded concrete 1, and the slab rebar 4 is assembled on the upper part, and then the foundation slab concrete 6 is placed. However, the present invention is not limited to this, and it is widely used as a technique for preventing an electrical short circuit between the electrode for anticorrosion laid on the lower concrete and the rebar assembled on the upper part. Can be used.

  DESCRIPTION OF SYMBOLS 1 ... Abandoned concrete (lower layer concrete), 2 ... MMO anode electrode (electrode for electric protection), 3 ... Protective concrete, 4 ... Slab reinforcement (rebar), 5 ... Number wire, 6 ... Foundation slab concrete (upper layer concrete)

Claims (3)

A first step of laying an electrode for cathodic protection on the lower side concrete;
A second step of placing protective concrete so as to cover the electrode for anticorrosion on the lower-layer side concrete;
A third step of assembling the reinforcing bars after placing the protective concrete;
A fourth step of placing the upper-layer side concrete after the rebar is assembled;
A method for constructing a concrete structure characterized by comprising: The lower layer side concrete is discarded concrete,
The rebar is a slab rebar,
The concrete structure construction method according to claim 1, wherein the upper-layer side concrete is foundation slab concrete.   The construction method for a concrete structure according to claim 1, wherein the electrode for cathodic protection is composed of a composite metal oxide mainly composed of titanium.

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