JPH06207922A - Monitoring method for corrosion/corrosion-resistance of underground piping passing through ferroconcrete structure - Google Patents

Abstract

PURPOSE:To provide a corrosion/corrosion-resistance monitoring method enabling the corrosion/corrosion-resistance monitoring of an underground piping passing trough a concrete structure without requiring excavation of earth and sand at all. CONSTITUTION:An assembly 9 of a combination of a reference electrode 11 and/or a corrosion/corrosion-resistance detecting probe 10 is projected into a hole 7 formed in the external ground passing through a concrete wall from inside a concrete structure 1, in the vicinity of a part where an underground piping 2 passing through the concrete wall. The assembly 9 is fixed to the concrete wall. Accordingly, it becomes possible to monitor the corrosion/ corrosion-resistance without requiring excavation of the outside earth and sand from inside of the concrete structure 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for monitoring corrosion protection of underground buried pipes that penetrate reinforced concrete structures.

[0002]

2. Description of the Related Art As shown in FIG.
When the underground buried pipe 2 penetrating the reinforced concrete structure 1 such as a bridge comes into contact with the reinforcing bar 3 at the penetrating portion, C / S
When a macro cell is formed and there is a risk of corrosion, in addition to excavation from the ground and burying electrodes in the structure, conventionally, the following measures are taken. That is, as shown in FIG. 3, a large number of galvanic anodes 4, ... Are installed, as shown in FIG. 4, the galvanic anode 4 is surrounded by a flexible sheet 5, and the galvanic anodes 4 are installed.
As shown in (4), the insulation improvement 6, 6 ', etc. of the penetrating portion are provided.

By the way, when the above-mentioned electrolytic protection is applied, as a method for confirming the anticorrosion effect, the ground potential of the underground buried pipe is measured from the ground by using a reference electrode, or the underground buried pipe is preliminarily measured. If a reference electrode is buried in the vicinity and measured, and the ground potential thereof is, for example, −850 mV or less as a value converted to a saturated copper sulfate electrode, it is considered to be anticorrosion.

Alternatively, a specimen having the same material as that of the underground buried pipe and a known surface area is buried in the vicinity of the underground buried pipe in advance, and the current between the sample and the underground buried pipe is measured. For example, if the direction of the current is flowing into the specimen in the soil, the current is also flowing into the underground buried pipe, so it is estimated that it is protected from corrosion, and the measured current is also tested. Dividing by the surface area of the piece gives the current density flowing into the test piece, so the corrosion protection current density to the underground buried pipe in the vicinity of that was estimated, and it was carried out by confirming whether the required protection current density was reached. .

Even if the anticorrosion is not applied, the ground potential of the underground buried pipe is measured as described above or the current between the test piece and the underground buried pipe is measured to determine the direction and size of the underground. The corrosion status of the buried pipe was monitored. For example, if the direction of the current between the test piece and the underground buried pipe is the direction in which the sample flows out in the soil, it is estimated that the underground buried pipe tends to corrode or the outflow current is If it is divided by the surface area, the outflow current density from the test piece can be known. Therefore, the outflow current density from the underground buried pipe in the vicinity thereof can be estimated, and the extent of corrosion of the underground buried pipe can be inferred.

Alternatively, the ground potential of the underground buried pipe is -500 to -600 mV (spontaneous potential of steel in soil) or more, for example, -200 to -40 in terms of a value converted to a saturated copper sulfate electrode.
If it becomes 0 mV (natural electric potential of steel in concrete), it is estimated that the underground buried pipe is in electrical contact with the reinforcing bars in the concrete, and the underground buried pipe tends to corrode.

[0007]

However, when burying these reference electrodes and test pieces in the vicinity of the underground burial pipe, there is no particular problem when burying at the same time as the pipe burial, but when burying after pipe burial. It is essential to excavate the outside of the structure, but in many cases it is difficult or impossible due to the large depth and the existence of ground facilities such as paved roads and veneer walkways. Also, even if it is buried at the same time as the pipe is buried, if there is a failure or inconvenience in the middle, it is often difficult or impossible to excavate from the outside of the structure like the above, so replacement is not possible, In some cases, sufficient corrosion / corrosion protection monitoring was not possible.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method capable of sufficiently and long-term corrosion / corrosion monitoring without excavation on the outside of a structure.

[0009]

In order to achieve the above object, a method for monitoring corrosion and corrosion of an underground buried pipe penetrating a reinforced concrete structure according to the present invention is to measure the inside of a concrete structure near a concrete wall penetration part of the underground buried pipe. Further, the assembly mounted by combination with the reference electrode and / or the probe for detecting corrosion and corrosion is projected into the hole in the outer soil through the concrete wall, and is fixed to the concrete wall.

[0010]

[Operation] The cylindrical assembly that is inserted from the inside of the concrete structure to the hole in the outer soil enables monitoring of corrosion and corrosion of underground pipes without excavating the outer soil.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS This will be described in detail below with reference to the drawings.
In the figure, 7 is a hole formed in the soil 8 in the vicinity of the penetrating portion of the underground buried pipe 2 through the concrete wall from inside the structure with a concrete cutter or the like. Reference numeral 9 in the drawing denotes an assembly which is attached to the hole 7 from the inside of the structure, and after attachment, the concrete wall is fixed by applying measures such as water stop and insulation.

The assembly 9 comprises a probe 10 and / or a reference electrode 11 according to the required corrosion and corrosion monitoring. When the underground buried pipe 2 is galvanically protected In the assembly 9 including the probe 10 and the reference electrode 11 as shown in FIG. 1, the reference electrode 11 measures the ground potential of the underground buried pipe 2 and the probe 10 and the underground. By measuring the current with the buried pipe 2, that is, the current flowing into the probe 10, the corrosion protection of the underground buried pipe 2 can be monitored in the reinforced concrete structure 1.

Further, in the assembly 9 composed only of the probe 10 as shown in FIG. 2, by measuring the current flowing into the probe 10, the corrosion protection monitoring for the underground buried pipe 2 can be performed in the reinforced concrete structure 1. Further, in the assembly 9 including only the reference electrode 11 as shown in FIG. 3, by measuring the ground potential of the underground buried pipe 2, corrosion protection monitoring of the underground buried pipe 2 can be performed in the reinforced concrete structure 1.

When the underground buried pipe 2 is not galvanically protected In the assembly 9 including the probe 10 and the reference electrode 11 shown in FIG. 1, the reference electrode 11 measures the ground potential of the underground buried pipe 2 and the probe 10 and the underground By measuring the current between the buried pipe 2 and the underground buried pipe 2, corrosion can be monitored in the reinforced concrete structure 1.

Further, in the assembly 9 including only the probe 10 shown in FIG. 2, the corrosion of the underground buried pipe 2 can be monitored in the reinforced concrete structure 1 by measuring the current flowing into the probe 10. Further, the assembly 9 including only the reference electrode 11 of FIG.
Then, by measuring the ground potential of the underground buried pipe 2, the corrosion monitoring of the underground buried pipe 2 can be performed in the reinforced concrete structure 1. The reference electrode 11
Examples thereof include a zinc reference electrode and a lead reference electrode. The probe 10 is preferably made of the same material as the underground buried pipe 2.

[0016]

As described above, according to the present invention, it is possible to easily and economically monitor the corrosion protection of the underground buried pipe 2 only in the concrete structure 1 without any need to excavate the external sediment. Further, since the assembly 9 is provided from the indoor side and can be collected from the indoor side, it can be easily replaced at all times, and sufficient and long-term perfect monitoring can be expected.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method of the present invention.

FIG. 2 is an explanatory diagram of a method of the present invention.

FIG. 3 is an explanatory view of the method of the present invention.

FIG. 4 is an explanatory diagram of a portion targeted by the present invention.

FIG. 5 is an explanatory diagram of a portion targeted by the present invention.

FIG. 6 is an explanatory diagram of a portion targeted by the present invention.

FIG. 7 is an explanatory diagram of a part targeted by the present invention for both a and b.

[Explanation of symbols]

 1 Reinforced concrete structure 2 Underground buried pipe 3 Reinforcing bar 4 Galvanic anode 5 Flexible sheet 6,6 'Insulation improvement 7 Holes 8 Soil 9 Assembly 10 Probe 11 Reference electrode

Claims (1)

[Claims] 1. A submerged underground pipe is provided with a reference electrode and / or a corrosion / corrosion detection probe in combination with a reference electrode and / or a corrosion / corrosion / corrosion detection probe, which is installed in an underground hole of a concrete structure that penetrates through concrete from inside the concrete wall. A method for monitoring corrosion and corrosion of an underground buried pipe penetrating a reinforced concrete structure, characterized in that the assembly is projected and fixed to the concrete wall.