KR100292976B1 - Method of manufacturing titanium wire net for improving durability of rc concrete structure - Google Patents

Abstract

PURPOSE: A method of manufacturing a titanium wire net for improving durability of RC concrete structures is provided, in which by supporting conventional titanium wire net with metals such as iridium oxide, platinum, cobalt, tin, selenium, ruthenium oxide, and iron, RC concrete structures are prevented from being corroded. CONSTITUTION: The method of manufacturing a titanium wire net for improving durability of RC concrete structures includes the steps of (i) dissolving 100g of metal composition in an acidic solution having a hydrogen ion-concentration of pH4-7 wherein the metal composition comprises iridium oxide 40-63%, platinum 20-30%, cobalt 12-24%, tin 4-8%, 0.5-4% of at least one metal selected from selenium, ruthenium; (ii) immersing a titanium wire net in a mixed solution that is added with polyvalent alcohol as a viscosity control agent until its density become 30-70sec by using NO.3 and NO.4 of viscometer; and (iii) thermal fusing at a temperature range of 400 to 700deg.C.

Description

Manufacturing Method of Titanium Metal Mesh for Extending Durability of RC Concrete Structures

The present invention provides a titanium metal mesh for reinforcing and extending the life of RC concrete structure. More specifically, it can be contaminated from the existing RC concrete structure contaminated with chloride, emulsion, nitride, or the like using titanium metal mesh. The present invention provides a method of manufacturing an improved titanium metal mesh that can prevent the corrosion of reinforcing bars due to concrete neutralization and salt damage caused by reinforcing corrosion of new RC concrete structures and carbon dioxide in the air.

The present invention is to connect the titanium metal mesh as an anode and the steel as a cathode for the RC concrete structure in which chloride ions penetrating into the concrete and reinforcing corrosion due to the increase of concrete neutralization and use of sea water, and the electric It is a technical field related to the titanium anode network that extends the life of the structure as well as strengthening the durability of the structure by stopping the corrosion of the steel and restoring the interior of the concrete by chemical action. Reinforcing corrosion of reinforcement is a means of reinforcing the reinforcing bar itself or waterproofing the concrete surface to prevent chloride ions from penetrating.In RC concrete structures, the corrosion of reinforcing steel due to cracking, deterioration and neutralization of concrete surface layer is in progress. In the state By performing repairing methods such as FRP and carbon fiber reinforced compression on the lower slab of the concrete structure, long-term wet state is generated due to the re-deterioration of reinforced concrete structures and the liquefaction of gases generated on the adhesive interface with existing concrete structures. The early defects such as dropping of the recurrence problem will occur.

A more advanced method of the prior art is a means of using a conductive overlay as the anode, in which case the anode is a mixture of asphalt, coke powder and aggregate mixed with high silicon cast iron that functions as a current contact material. In the system, when the current flows uniformly on the slab surface, the anode surface is large because the anode surface area is large.

However, coke and asphalt overlays show structural collapse and must be partially replaced or repaired within a few years.

And if the concrete under the overlay is accompanied by air irregularly it causes deterioration by repeated freezing and dissolution.

In addition, the slit type non-overlay anode system was developed to extend the surface of the anode and expand the applicability, while constructing an area that does not increase the load and height of the upper slab. The grooves are made long at regular intervals, and anodes are planted in these grooves, and filled with a conductive mixture of carbon and organic resin, which functions as a surface of the anode.

Since the anode has a limit on conductivity, a current is supplied to the anode by a metal wire or a carbon wire conductor.

Since the anode has a small surface area, the adjacent concrete is eroded from the acid or gas of the anode reactant, and the groove is widely separated. Therefore, the current distribution of the reinforcing steel is not uniform and there is no redundancy in the current connection. The effect is greatly diminished, high costs are required for maintenance and installation, and workability is difficult.

In addition, an ion conductive overlay, a conductive polymar grout anode made of carbon and organic resin, is installed on the upper slab surface, such as a metal wire and a carbon conductor current conductor, and coated with concrete thereon, and a rigid non-conductive overlay extends the slab life. It has the advantage of minimizing deterioration due to freezing or melting of concrete underneath by inhibiting the penetration of chloride, but this system is also attacked by acid or carbonate gas which is caused by electrochemical reaction of conductive organic resin mixture with carbon. There is an easy issue.

In addition, there is another plastic material of the rigid ion conductive overlay and the use of the cathode material, which is made of a large net with a continuous cable, placed on the upper slab and coated with the rigid overlay.

Such a system takes less time to install but does not have good faults and power distribution without acid or gas attack and network redundancy. Such a polymer anode can be exemplified in U.S. Patent No. 447350. If kebur is cut at the part, the cathodic anticorrosive effect is reduced in a considerable area.

In addition, U.S. Patent No. 450485 is an example of using a fused zinc anode, and since the natural voltage of zinc is very low, it does not emit a proper mode current over a sufficient distance to the reinforcing bar in concrete, so the need for a power supply and current distribution system is required. This is further required.

This creates many problems with the expandable corrosion products of zinc.

As mentioned above, all systems for treating rebar in the cathode method have used carbon as the cathode surface, except for the system using the zinc anode, but the carbon is used for the cathode method. Because of this very high anode surface area, anode cost has to be low, so inexpensive carbon has been used.

However, since carbon is not suitable for the interior of concrete, the physical form of carbon has been used in combination with concrete, together with thermoplastic polymer organic resin and paint mastic.

In addition, due to other shortcomings of carbon, in actual construction, carbon has lower electrical conductivity than metal and requires accurate current conductor system, and carbon is thermochemically unstable and reacts and is harmful to cement such as carbon dioxide, carbonic acid, and carbonate. To form the product.

In addition, carbon is an electrochemically inert anode, and the anode potential of the carbon anode is relatively high when operated in contaminated concrete of chloride and generates chlorine gas and hypochlorite, and the reaction product is a strong oxidizing agent, and thus reacts with organic complexes. This causes problems with anode life.

As described above, the reinforcing cathode method in concrete is insufficient to satisfy the required properties among the anodes used in the related art.

For example, considering economics, there are advantages, but sufficient area is needed to prevent deterioration of the concrete adjacent to the anode, but there are many methods that are practically difficult and ideal current distribution due to the structure of the structure and construction problems. Most of the methods are causing serious problems.

As a more improved method to solve the above problems, a metal network has been introduced that multiplexes the current circuit, ideally distributes the current, has dimensional stability, and generates little carbon dioxide or chlorine in chloride-contaminated concrete.

Such a metal mesh is a titanium anode metal mesh such as square, hexagon, honeycomb, etc. has made breakthroughs in the art.

However, research on the effect of the current density of titanium metal mesh on the suppression concrete of the product by the ideal current distribution electrochemical reaction has emerged as a big problem.

In the concrete structure, the metal composition is coated on the surface of the titanium metal mesh used in the electrochemical system using the rebar as the cathode and the anode as the titanium metal mesh, thereby reducing the consumption of the metal mesh and facilitating current distribution, thereby preventing concrete neutralization and It is to maximize the life of concrete structure by preventing corrosion of reinforcing steel and preventing degradation of cement by acid.

1 is a diagram illustrating a state of reinforcing corrosion of a conventional concrete reinforced structure.

Figure 2 is a titanium anode network according to the present invention in the reinforcing bar structure of the corrosion protection reaction state.

The present invention provides a method for producing a titanium metal mesh, that is, a titanium metal mesh loaded with a new metal composition, for use in an electrochemical system using reinforcing bars as cathodes and titanium metal meshes as anodes in RC concrete structures.

Prior to the present invention, in the concrete structure, concrete neutralization, salt, and corrosion mechanism of reinforcing bars due to acid flow will be described first. In concrete neutralization, when a concrete structure is exposed to natural environment for a long time, carbon dioxide in the air penetrates into the concrete, It reacts to produce lime carbonate and neutralization proceeds.

At this time, the neutrality is gradually neutralized at pH 12.5-13 of general high-quality concrete, and when it reaches PH 8.5-9.5, alkalinity is lost. Therefore, the passivation film is destroyed on the surface of the reinforcement in the alkali, and the oxide is formed and the corrosion is started. Cracking and peeling occur due to the volume expansion pressure.

The second cause is the cause of the use of a maritime arising from the use of the use of the ice-making maritime and Cl ^-, SO ₄ ^-, etc. penetrate the chloride content of the concrete inside the predetermined amount the amount of sulphate or when more than 300ppm in the If exceeded, the rebar begins to corrode, and when the ice maker is used, chlorides such as calcium chloride and sodium chloride penetrate into the concrete. If the chloride content penetrates more than 300ppm, concrete cracking and peeling may occur.

The third cause is in when, for example, penetration of acids SO _X, NO _X salts to penetrate because the salt is produced by reacting with the cement hydrate standing cement hydrate is decomposed.

This leads to chemical erosion of the concrete surface and to the decay of the concrete tissue and the reinforcing steel, which leads to the deterioration of the strength of the cement structure.

With the destruction of the passive film of the reinforced surfaces and concrete interior due to concentration difference between the salt and alkali, the potential of the reinforcing surface macroscopically nonuniform while contaminated with salt ^- more specifically in a chloride penetration into the concrete surface (Cl) As shown in FIG. 1, an anode (+) and a cathode (−) are formed to form an electrical circuit. At this time, an oxidation reaction, which is an electrochemical reaction, occurs and a corrosion reaction occurs at a bonded portion of a salted steel.

1 is a corrosion state diagram of reinforcing bars in a conventional concrete reinforcing structure and the symbol A represents a reinforcing bar.

Or more and functions of the electrochemical system of the anode and the reinforcement as cathode to corrosion caused by concrete oxidation degradation and reinforced, such as a titanium wire mesh is a chloride ion (Cl ^-) to penetrate into the concrete inside the electrochemically, such as a reinforced surface hameuroseo ^{producing-hydroxyl} group (OH) in the reinforced-corrosion factor positive (+) with basically by blocking the corrosive sikimyeo completely stop the corrosion of corrosion of the reinforcing bar also the cathode occurring due to the concrete carbonation Transfer () Regenerates the passivation film to stop corrosion of the rebar.

In more detail, by applying an electrochemical method, as shown in FIG. 2, the steel is connected to a cathode by using a positive electrode network of positive electrode (+) and the rebar as a negative electrode (−), and thus the rebar is negative on the corrosion mechanism (−). stopping the corrosion of the reinforcement which is to be the reinforced surface negative (-) in alkaline a hydroxyl group (OH ^-) by the electrochemical reaction, according to the generated film passivation of reinforcement surface being played back corrosion of the reinforcing bar due to the concrete carbonation Also stops.

In particular, as the hydroxyl group (OH ⁻ ) generated in the cathode, which is the surface of the rebar, moves toward the anode (+), the concrete interior gradually becomes alkaline.

Further corrosion factors, Cl ^-, SO ^-, S ^-, etc. go to the titanium mesh anode, and Cl ^-, SO ^-, S ^- and the like does not occur because the corrosion moved to the positive electrode.

2 is a state diagram showing the anti-corrosion reaction of the reinforcing steel in the concrete reinforcing structure using the titanium anode network according to the present invention and symbol B represents a titanium metal mesh.

Titanium metal network according to the present invention also has an anticorrosive function based on the same principle, but in the electrical system consisting of smooth current distribution, current density per unit area of concrete, reinforcement of the reinforcing structure as a cathode and titanium metal network as the anode To provide an efficient electrochemical reaction and a method for producing a titanium metal network to maximize the life of the anode according to the consumption delay caused by oxidation of the anode network, such a metal network is composed of various metals and metal oxides in the titanium metal network It is possible to achieve the object of the present invention by supporting the coating.

Titanium metal mesh according to the present invention is dissolved in one or more metals of iridium oxide (IrO ₂ ), platinum, cobalt, tin, iron and selenium, rhodium, rudenium in hydrochloric acid solution or nitric acid solution or mixed aqua regia As a viscosity modifier of this solution, a mixed solution containing a polyhydric alcohol was immersed in a titanium metal mesh to impregnate the mixed solution, and then sufficiently heat treated at a temperature of 400 ° C. to 700 ° C. until a low melting point metal such as tin and selenium was sufficiently melted. Titanium metal mesh characterized in that.

Titanium metal mesh used in the above method is composed of diamond-shaped flat plate rhombus aggregates, and the thickness of titanium metal mesh can be in the range of 0.5mm to 2mm and can be used from 1cm to 2m of the width of titanium anode network. Its scope is determined by its use.

In addition, the size of the rhombus may vary depending on the application, but the standard titanium metal mesh can be shown in Table (1), and the method of obtaining the metal mesh is thin titanium having a certain width.

It is formed by continuously pressing punching a metal plate.

For example, the metal mesh obtained by the punching method is superior to the overall function as the electrical conductivity, durability, and anode network than the metal mesh formed by spot welding of titanium wire or any other connection method. have.

In addition, the composition ratio of the composition supported on the titanium metal mesh is 40-63% of iridium oxide, 20-30% of platinum, 12-24% of cobalt, 4-8% of tin, 0.5-1.5% of iron and selenium, A metal composition composed of 0.5-4% of one or more metals among rhodium and ruthenium.

In this method, acid is in the range of PH 4-7, dilution uses distilled water, and polyhydric alcohol, tri-ethylene glycol, fury pyrene glycol, etc., and the added viscosity is ZAHN CUP concentration meter NO. .3 and 4 can be used if the viscosity in the range of 30 seconds-70 seconds, and the pH range of the mixed solution can be achieved if the pH range of 4-7 range can be achieved and the amount of the metal composition to be added to the acid solution is 20- About 30 g of metal composition is added to 30 l.

The composition used as the supported metal and its composition ratio are the metals with catalytic function and their electrical conductivity, current density, rate consumed by oxidation of anode network in electrochemical system, and bond strength by thermal fusion of titanium metal network. It can be said that it is the optimal composition and composition ratio which considered.

In addition, the viscosity can appropriately control the amount of metal adhering to the titanium metal mesh and when the pH is excessively acidic, an explosive violent reaction occurs, resulting in danger as well as lowering the function of the viscosity modifier.

In the above deposition process, the titanium metal mesh is eroded by acid and roughened so that the metals of the composition can be well supported on the titanium metal mesh surface and coated. In the heat treatment process, various acids or alcohols evaporate completely and the melting point is 232 ℃. Low melting metals, such as tin having tin and selenium having a melting point of 217 ° C., are melted to strongly adhere high melting metal particles to the titanium metal mesh.

The titanium metal net obtained by the above method can greatly increase the current density compared to the conventional titanium anode metal net when applied to RC concrete reinforcing structures, thereby improving current distribution by increasing the current density per unit of concrete.

And a hydroxyl group (OH ^-) according to electrochemical systems for the reinforcement as the cathode and a titanium metal mesh in the RC concrete structures with an anode passive film PLAY corrosion factor of chlorine ions in the reinforced surface of the generation (Cl ^-, SO ₄ ^{- -,} S ^-) is increased, moves the function of the titanium mesh anode, such as larger end extends significantly the life of the concrete structure RC.

In the electrochemical system using the reinforcement of RC concrete structure as the cathode and the titanium metal mesh as the anode, the metal mesh according to the present invention is suitable for safety, corrosion resistance, strength, and light weight, and the metal mesh itself is a rhombus aggregate. It consists of a metal mesh on the plate and forms thousands of multi-current circuits, so that even if any part is cut, smooth current distribution can be achieved.Titanium metal mesh has a thermal expansion coefficient similar to that of concrete, preventing breakage or cutting due to thermal expansion or thermal contraction. In particular, the titanium metal mesh is coated with a composition composed of metal and oxide to maximize the current density and greatly extend the life of the metal mesh from about 45 years to about 65 years, thereby extending the life of RC concrete reinforcing structures. It can be called a titanium metal net that can be significantly extended.

In order to clarify the technical configuration of the present invention and to examine the effect thereof is shown in the examples.

Example 1

Iridium oxide 500, platinum 230, cobalt 180, tin 60, selenium 20, iron 10 were added to 250 l aqueous solution of aqua regia in the concentration range of PH 4-7 Titanium according to the present invention by immersing the titanium metal net as the standard in Table (1) stated in the mixed solution adjusted to the viscosity to 50 seconds with NO. A metal net was obtained.

The test results of this metal net are shown in Table 2.

The electrochemical system using the above-mentioned titanium metal net as an anode is used for the upper and lower slabs of bridges, bridges and concrete beams, under concrete, under water boxes, marine RC structures, and elevated road access roads and bridges using winter ice making agents, interchanges. Reinforcement of existing concrete structures and reinforcement of new concrete structures by applying concrete to RC concrete structures using maritime, such as subway and railroad crossings, RC structures exposed to salt and underground parking lot of public buildings, etc. It is possible to extend the service life of RC concrete reinforcement structure by applying to the repair method.

In addition, it is possible to improve reinforcement and repair technology by developing an excellent anode network economically, and to reduce repair cost by extending the life of RC concrete structure, and to install this method on new RC concrete structure or existing RC concrete structure. Afterwards, the internal condition of the structure can be monitored in the office, thereby reducing the cost of safety management of the structure, and the development of a titanium anode network can contribute to enormous foreign currency saving and foreign currency acquisition.

In particular, most of Korea's concrete structures, which had been in the process of large collapse and high growth in Seongsu Bridge and Sampoong Department Store, caused serious problems in the safety of structures due to the neutralization of concrete and corrosion of steel. The construction method using the metal net can be called an urgent construction method, and as a result of applying it to the renovation of existing buildings or existing buildings in the underground parking lot of Seongsan Bridge, Seongsu Bridge, Mokpo, Busan Pier, and other apartments and public buildings, there are no problems yet. In addition, better results are expected from the development of the titanium anode network according to the present invention.

Claims (2)

Add polyhydric alcohol as a viscous agent to a solution of 100 g of metal composition dissolved in 20-30 l of hydrochloric acid or nitric acid solution such as PH4-7 or acid solution such as aqua regia. 30 seconds to 70 seconds with Viscosity Viscometer NO.3 and NO.4 Durability of RC concrete structure characterized by immersing the plate-like titanium metal mesh composed of rhombus aggregates in the mixed solution adjusted to the viscosity of Method of producing a titanium metal mesh to extend. The composition of claim 1, wherein the composition ratio of the metal composition is 40-63% of iridium oxide, 20-30% of platinum, 12-24% of cobalt, 4-8% of tin, 0.5-1.5% of iron, selenium, rhodium, Method for producing a titanium metal mesh to extend the durability of the RC concrete structure, characterized in that 0.5 to 4% of the at least one metal in rudenium.

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