JP2001020532A - Method for modifying and reinforcing concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for modifying and reinforcing concrete that enables remedying the causes of concrete defects with a chemical and improving concrete into sound concrete to provide for durability. SOLUTION: A channel 6 with a predetermined width and a predetermined depth is formed in advance in the portion of a concrete face corresponding to the periphery of a construction section, and an inorganic or resin type filler is injected into the groove 6 at low pressure. After a porous or fibrous laminate 12 is bonded to the concrete face in the construction section, a plastic film 13 is laid thereover and sealed at its periphery, and then the inside of the plastic film 13 is decompressed into a vacuum, after which a chemical is fed into the plastic film 13 and impregnated into every deep part of the concrete via the porous or fibrous laminate 12 sucked thereto by decompression.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing and reforming concrete for suppressing cracks and structural destruction of concrete and deterioration of concrete, and for strengthening already generated portions and improving durability. About.

[0002]

2. Description of the Related Art In the era when river gravel and river sand were used as aggregate for concrete, concrete was of good quality and excellent in durability.

However, due to the building boom during the high growth period, civil engineering structures such as railway viaducts and highway viaducts, which are social capital, and concrete aggregates used for building structures are made of sea sand and rock. Many are made of crushed stone.

[0004] Among crushed stones, when crushed stones containing expansible aggregates (reactive silica) which are often contained in pyroxene andesite are used, sodium (Na ⁺ ) and potassium contained in cement components and sea sand are used. It reacts with (K ⁺ ) and expands. This phenomenon is called an alkali-aggregate reaction. If this phenomenon occurs in large quantities at the same time and exceeds the binding force of concrete, explosive cracks run in a turtle-like shape and length and breadth, and the concrete strength decreases. Eventually, corrosion of the internal rebar causes fatal destruction.

As a method for suppressing such alkali-aggregate reaction, there are a resin coating waterproofing method, a lining method, and the like in which the supply of water or alkali is stopped surface-wise. It was not too much.

[0006] Lithium nitrite (eg, manufactured by Nissan Chemical Industries, Ltd.) is one of the therapeutic and prophylactic drugs that have been spotlighted. It is well known that the lithium ion of this component reacts with reactive silica to insolubilize the surroundings of the expandable aggregate and suppress the reaction expansion, as reported by the Japan Concrete Institute and others. However, it is difficult to impregnate the lithium ions deep inside the concrete with a large amount of an effective amount. Even if it is applied three times with a brush, the limit is 350 to 500 g, and the only way to supply a larger amount is to mechanically forcibly inject it.

[0007] Next, regarding the countermeasures against deterioration due to salt damage, there are damages due to salt in sea sand, damage to flying salt in the near sea, salt damage in food factories, and the like. In this case, the salt supplied later can be dealt with by a method of blocking the surface, but it is impossible to extract the salt which has already entered the concrete. It is well known that nitrite ions are supplied to the reinforcing bar position to form a passivation film layer (Fe ₂ O ₃ ) to prevent rusting of the reinforcing bar. It is difficult to impregnate an effective amount into the depth.

[0008] Conventional methods include brushing lithium nitrite and gradually penetrating and diffusing mixed mortar, but it takes three months or more to reach the target depth. Since rust progresses, quick action is required.

[0009] In addition, it is effective to use a method in which concrete whose surface layer is weakened by a substance harmful to concrete such as acid rain or factory chemicals is cut off and coated with a new material. However, if it is desired to improve the existing surface by strengthening the surface layer, the reinforcement must be impregnated with the reinforcing agent to the deep fragile layer of the concrete. Conventionally, a method of brushing or spraying lithium silicate or acrylic resin or the like to solidify the surface has been used. However, the desired depth was not reached, and the result was unsatisfactory of only 3 mm or less.

[0010]

DISCLOSURE OF THE INVENTION The present invention solves the conventional problems, and is the only problem of a drug which has already been highly evaluated for its effectiveness. Various problems, such as securing and shortening the penetration rate, are solved at once, and the cause of the defect in the concrete is treated with chemicals to improve the soundness of the concrete and to improve the durability. In particular, it is intended to maintain the durability of expressways and Shinkansen viaducts, tunnels, dams, and other social capital structures that are said to be impossible to rebuild.Specifically, cracks and salt due to alkali-aggregate reaction Reinforces concrete strength and neutralization and strengthens degraded surface layer by injecting chemicals evenly and deeply into parts that are weakened due to corrosion of steel bars, other chemical damage to concrete, acid rain, etc. by mechanical forcing. And to provide a method for improving the quality of the concrete itself.

[0011]

In order to achieve the above-mentioned object, a method for strengthening and modifying concrete according to the present invention provides a groove having a predetermined width and a predetermined depth in a portion of a concrete surface around a construction section. Is formed, and an inorganic or resinous filler is injected into the groove at a low pressure, and a porous or fibrous laminating material is adhered to the concrete surface of the construction section, and a plastic film is laminated and adhered. Is sealed, and then the inside of the plastic film is evacuated and evacuated, and then a drug is supplied into the plastic film through a porous or fibrous laminate that is adsorbed by the reduced pressure. Therefore, the chemical is impregnated deeply into the concrete.

The present invention provides a rapid effect on the prevention and treatment of alkali-aggregate reaction and rebar corrosion which destroy concrete by forcibly injecting nitrites as a concrete modifying agent.
Since nitrite alone is not very effective in treating and preventing corrosion of reinforcing steel due to salt damage, further effects and durability can be obtained by supplying silver nitrite mixed with nitrite and silver ions. The fragile layer of concrete, which has already deteriorated due to acid rain or other factors, is reinforced by forcibly injecting silicate or acrylic emulsion resin. Furthermore, quality control can be performed by repeating the supply of the medicine several times.

According to the method for reinforcing and modifying concrete of the present invention, the concrete surface to which the porous material is attached is coated with a plastic film and sealed, and the pressure is reduced to bring the concrete body into a vacuum state, and then the chemical is supplied. Is what you do. For this reason, the concrete modification strengthening method of the present invention,
The required amount of the drug can be surely permeated and supplied to the required depth.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, as shown in FIG. 1, a concrete skeleton 1 as an object is often provided with a reinforcing bar 2, and a crack generated in the concrete has a penetration crack 3 of 1 mm or more and a crack of 0.3 mm or more. There is a crack 4 of less than 0.0 mm and a crack 5 of less than 0.3 mm that does not significantly affect water leakage and strength.

An important object of the present invention is to ensure airtightness of an object. To do so, the air flowing through the crack must be shut off. For large areas,
For once construction of the total area is impossible, it was performed by dividing the 5 m ² of the area of conforming to the ability of the decompressor to 6 m ² unit. However, when a decompressor having a large capacity is used, the construction area can be enlarged once.

A section having a width of 2 m and a width of 3 m = 6 m ² is defined as a section, and a groove having a width of 2 mm to 3 mm and a depth of 50 mm or less is dug around the section, and a crack width 0.3 in the range is formed.
The surface of the inorganic sealing material including those having a diameter of not less than mm is sealed with a trowel or a spatula. Epoxy-based or other resin-based sealing materials can also be used. 1 on the cracked line
Injection holes or injection pedestals 8 at intervals of 0 to 50 cm
Attach.

In the present embodiment, since the test was conducted at a crack site caused by an alkali-aggregate reaction, lithium nitrite was used as a drug, and a chemical pump was used to press-in it with a chemical pump to perform pre-injection until the cracks reached a wet state. However, since the pre-injection agent differs depending on the deterioration factor of the concrete, the pre-injection may be performed using only fresh water without using the agent.

A low-pressure injector 9 containing an injecting agent 11 is attached to an injecting pedestal 8 attached to a boundary sealing seal 6 and a line of cracks 3 and 4 having a diameter of 0.3 mm or more. As the injection proceeds, the gap is gradually filled. Due to the effect of the filler in this work, the flow of air from the back surface of the concrete and from the surroundings is suppressed, and airtightness is maintained. However, the material to be injected into the boundary sealing seal 6 and the cracked portions 3 and 4 may be any resin-based material such as an epoxy-based or acrylic-based material having a high fluidity, in addition to the inorganic-based slurry.

Next, as shown in FIG. 2, in the frame of the boundary sealing seal 6, three porous cushioning materials 12 each having a thickness of 10 mm, a length of 2 m, and a width of 1 m are connected to each other and attached to the target surface with an umbrella nail or the like. wear. After that, the whole is covered with a plastic film 13 and the terminal is attached to the boundary sealing seal 6 with a resin-based adhesive sealing material 14 to complete the sealing. However, the porous cushion material 12 may be a material having a thickness of 10 mm to 50 mm or a fibrous material such as cotton, depending on the application. The plastic film 13 is classified into an aqueous type, an alcohol type, and an organic solvent type depending on the type of the chemical, and a material suitable for the physical properties is selected and used.

At the lower center of the sealed plastic film 13, a medicine supply hole 16 is attached. Further, a reduced pressure suction hole 15 is attached to the center or both ends of the upper portion with an adhesive. Then, a drug supply hole 16 is connected to the drug tank 17 using a hose. The pressure reducing compressor 19 and the pressure regulator 2
0 and the reduced pressure suction hole 15 are connected using a suction hose 22. Then, the inside of the plastic film 13 is depressurized by operating the decompression compressor 19 to make the inside of the plastic film 13 into a vacuum state, and then the medicine valve 18 of the medicine tank 17 is opened to supply the medicine gradually. The chemical fills up to the top via the porous cushion material 12 and gradually penetrates deeper from the surface of the concrete skeleton 1 as the object.

When the supply of the medicine reaches the required amount, the medicine valve 18 is closed to stop the supply. In addition, the suction hole valve 2
Also tighten 3 to seal. When the medicine supply hole and the suction hole are closed, the plastic film 13 is adsorbed with a stronger force by the decompression action, and the medicine in the porous cushion material 12 is rapidly pressed into the concrete frame 1. As the penetration of the drug progresses, the decompression force weakens, and the remaining drug solution moves downward and does not penetrate.Therefore, the suction operation is repeated until the remaining drug disappears, and it is determined that the injection is completed when the drug does not accumulate at the lower portion. To end the work.

[0022]

Since the present invention is configured as described above, it has the following effects.

(1) It is impossible to easily rebuild large important structures such as dams, power plants, road bridges, railroad bridges, etc., and how to perform improved maintenance for the purpose of maintaining durability. It is in. According to the present invention, concrete is reformed by accurately and forcibly injecting an effective amount of a chemical in accordance with such a deterioration factor of a structure in a short time, thereby treating a defective portion and a symptom that will occur in the future. Can be prevented in a short time and at low cost.

(2) Causes of rapid deterioration of concrete include strength reduction due to complex cracking due to alkali-aggregate reaction, destruction due to accelerated corrosion of internal reinforcing bars, and neutralization of concrete caused by acid rain and the like. It is said that the typical factors include weathering due to oxidation and expansion splitting caused by corrosion of reinforcing steel due to salt damage. In the conventional method, it has been carried out by the brushing method, the spraying method and the compressing method, but since there is no forcible force, it depends only on natural penetration force, and it is superficial even in the application amount and penetration depth and at most The limit was about 5 mm. ADVANTAGE OF THE INVENTION According to this invention, the durability of concrete is reliably extended by uniformly impregnating the required amount of the medical solution to the required depth, and an important and social contribution degree that meets the needs of the age of valuing things. It is a high construction method.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first step of a concrete reforming and strengthening method of the present invention.

FIG. 2 is a diagram illustrating a second step of the concrete reforming and strengthening method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete frame 2 Reinforcing bar 3 Cracks of 1.0 mm or more 4 Cracks of 0.3 mm to less than 1.0 mm 5 Cracks of less than 0.3 mm 6 Boundary seals for process sections 7 Crack seals 8 Injection base 9 Low pressure injector 10 Pressure spring 11 Injectant 12 Porous cushion material 13 Plastic film 14 Adhesive seal 15 Decompression suction hole 16 Drug supply hole 17 Drug tank 18 Drug valve 19 Decompression compressor 20 Pressure regulator 21 Suction adjustment valve 22 Suction hose 23 Suction hole valve

Claims (3)

[Claims] 1. A groove having a predetermined width and a predetermined depth is formed in advance in a portion of a concrete surface around a construction section, and an inorganic or resin-based filler is injected into the groove at a low pressure. After attaching a porous or fibrous laminate to the concrete surface, a plastic film is overlaid and sealed to hermetically seal the surroundings, and then the inside of the plastic film is depressurized and evacuated to a vacuum. A method for modifying and strengthening concrete, characterized in that a concrete is uniformly impregnated in a deep portion of a concrete through a porous or fibrous laminated material adsorbed by reduced pressure by supplying a medicine into a film. 2. The method according to claim 1, wherein the agent comprises a concrete modifier comprising nitrites or a mixture of nitrites and silver ions, or a monomer or polymer comprising silicates and a monomer or polymer comprising an acrylic resin. The method for modifying and strengthening concrete according to claim 1, wherein the method is one selected from concrete improving and strengthening agents. 3. The method for strengthening and modifying concrete according to claim 1, wherein the necessary amount of the chemical and the impregnation depth are adjusted by repeating the supply of the chemical several times.