JPH0394081A - Method for fitting insoluble electrode to concrete structure - Google Patents

Abstract

PURPOSE:To make it possible to stably impress electric current for electric protection over a long period of time by setting a meshy insoluble electrode on the surface of a concrete structure, pressing a protective sheet coated with an electrolyte against the surface of the structure with the electrode in-between and fixing the sheet. CONSTITUTION:A linear or meshy insoluble electrode 5 is set on the surface of a concrete structure 1. A protective sheet 6 coated with an electrolyte is pressed against the surface of the structure with the electrode 5 in-between and the coated side inward. The pressed sheet 6 is fixed in the surface of the structure with fixing tools 2, 4.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides an insoluble electrode used for cathodic protection of steel materials in reinforced concrete structures, breast-stressed concrete structures, etc. using an external power source. Regarding how to place.

[Conventional technology]

In the method of cathodic protection of steel materials (reinforcing bars, prestressing steel, steel frames, etc.) in concrete structures using an external power supply method, since concrete has a high resistivity and a thin cover, insoluble electrodes are used to supply corrosion protection current. It is necessary to cover the surface of the structure widely in order to make the current distribution uniform. For this purpose, when linear electrodes are used, the intervals between the lines are generally made close, or mesh electrodes are used.

When installing such a linear or mesh-like insoluble electrode (for example, diameter 1.2mXL) on the vertical or ceiling surface of a concrete structure, drill a hole in the concrete surface and make a hole with a diameter slightly larger than the diameter of this hole. A plastic pin is driven in, the electrode is fixed with the head of the pin, and the electrode is then coated with mortar to a thickness of about 20 mm by spraying or troweling.

[Problem that the invention seeks to solve]

In order to reduce the dead load of the structure, the mortar covering the linear or mesh-like insoluble electrodes must be made extremely thin to the extent that these electrodes are hidden, from an economic standpoint. However, for example, mesh electrodes are also less economical.
There is a tendency to use expanded titanium plates with a thickness of mm, which makes them difficult to flatten and requires a large number of bolts to ensure uniform spacing between the concrete surface and the work efficiency. This had the problem of an extremely low value.

In addition, since the covering mortar is applied by troweling or spraying, it loses its adhesion over time and there is a risk of peeling.

The present invention provides an electrode installation method that allows a linear or mesh-like insoluble electrode to be attached to a concrete surface with good adhesion without increasing dead load, and that enables a stable supply of anticorrosive current over a long period of time. The purpose is to

[Means for solving problems]

In the present invention, a linear or mesh insoluble electrode is set on the surface of a concrete structure, a protection plate coated with an electrolyte is pressed onto the concrete surface with the electrolyte coated side facing inside, and then fixed onto the concrete surface using a fixture. The above-mentioned problem is solved by press-fitting and fixing.

[For production]

In this way, in the present invention, a linear or mesh-like insoluble electrode is set on the concrete structure surface, a protective plate coated with electrolyte is pressed onto the concrete surface with the electrolyte coated side facing inside, and the fixing device is Since the electrode is fixed to the concrete surface by pressure, the increase in dead load is significantly reduced compared to conventional methods, and there is no gap between the electrode surface and the concrete surface, which improves adhesion and makes it easier to spray mortar, etc. is omitted, and the insoluble electrode can be installed in an extremely simple process without the risk of falling off.

The electrolyte used in the present invention can be any suitable electrolyte such as mortar or back fill. After applying these electrolytes to a thickness of 3 to 8 mm on the protective plate, the electrolyte is coated with fluidity before drying and solidifying. Press it against the concrete surface and secure it with a fixing device. When using mortar as the electrolyte, polymer cement mortar with a synthetic resin emulsion added to improve adhesion, or conductive mortar mixed with carbon fiber or graphite powder to improve conductivity, etc., may be used. Packfills include, for example, bentonite and a hygroscopic electrolyte kneaded with water, specifically aluminum silicate hydrate, metal sulfate, and magnesium chloride as shown in Japanese Patent Application No. 158484/1983. Examples include things like: When using this pack fill, a non-woven fabric or the like may be sandwiched between the pack fills to prevent sagging after being applied to the protection plate and before being fixed to the concrete surface.

Further, the protective plate in the present invention may be any plate-shaped body having a certain degree of rigidity and durability necessary for pressure contact, and an asbestos slate plate, an FRP plate, etc. can be used.

In the present invention, setting a linear or mesh-like insoluble electrode on a concrete surface means placing the electrode on the concrete surface and holding it to the extent that it does not move.
Specifically, it is temporarily fixed with a plastic pin, or if a bolt embedded in the concrete surface is used as a fixing device, the electrode is hooked onto this bolt.

Examples of the present invention are shown below.

Example This example shows the case where the present invention is applied to a concrete girder. The targets for corrosion protection were both sides and the bottom of the girder, and the length of the girder cross section was 2.2 m.

As shown in Figures 1 and 2, a 1.2 m long titanium mesh electrode 5 was cut into a length of 2.2 m, and the short end was fixed to the top of one side with a plastic pin. ,
It hung along the side of the girder.

6mm thick, 0.75m with 5 bolt holes for mounting
Apply mortar 7 to a thickness of 5 mm on an asbestos slate board 6 measuring 1.1 m in diameter, press it against the concrete surface from above the mesh electrode 5, and attach the anchor bolt 2 (previously attached to the girder 1 surface).
(made of plastic, insoluble metal, or ceramic) using a washer 3 and a nut 4. Similarly, protective plates 6 were attached to the corners and the bottom surface of the girder, and then to the other side surfaces.

However, the bottom protection plate had dimensions of 0.5 m x 1.1 m.

A titanium mesh electrode was placed next to and in contact with the construction site, a protection plate 6 was attached, and construction was carried out over the entire surface of the girder.

Apply mortar to the gap between the protective plates and attach the mesh electrode 5.
covered. The presence of the electrode contributed to the adhesion of the mortar as well as the metal lath.

〔Effect of the invention〕

As explained above, according to the present invention, the insoluble electrode used in the external power supply method is firmly fixed to the concrete surface via the electrolyte through a simple process, so the increase in dead load is significantly reduced, and it can be used for a long period of time. , a stable anti-corrosion current supply is ensured.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are schematic explanatory diagrams showing embodiments of the present invention. 1... Concrete girder 2... Anchor bolt 1~
3... Washer 4... Nut 5... Mesh electrode 6... Protective plate 7... Mortar 7 -8

Claims (2)

[Claims] 1. In the method of installing insoluble electrodes used for cathodic protection of steel materials in concrete structures using an external power supply method, a linear or mesh insoluble electrode is set on the surface of the concrete structure, and an electrolyte is applied over the protection. A method for installing an insoluble electrode on a concrete structure, which comprises pressing a plate against a concrete surface so that the electrolyte-applied surface faces inside, and fixing the plate to the concrete surface using a fixing device. 2. 2. The method for installing an insoluble electrode in a concrete structure according to claim 1, wherein the fixing device is a bolt whose one end is embedded in the concrete structure and a nut screwed into the bolt part.