JP2002295023A - Repair method for cracks in concrete - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a method for repairing cracks in concrete material, which can prevent water infiltration and maintain the prevention action. SOLUTION: The tearing part of the concrete material is filled with a repair member having a property of absorbing water and swelling, the surface or the tearing part of the concrete material is coated or filled with a water absorbing material, the surface of the concrete material or the tearing part. Applying or filling a resin containing a water-absorbing material to the surface, applying or filling a rust-preventive oil containing a water-absorbing material on the surface or the rupture of the concrete material, or swelling when the surface or the rupture of the concrete material is wetted. Immediately prior to application, etc., mix a repairing member having or a repairing member having the property of foaming, expanding in volume and elasticity with water with a medium for penetrating the repairing member, and applying in a colloidal state Alternatively, the material is penetrated by filling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extending the life of a concrete (reinforced) material whose deterioration has become apparent due to cracks.

[0002]

2. Description of the Related Art Cracks due to external force and drying shrinkage are occasionally observed in land structures using concrete materials. For example, it has been pointed out that cracks occur in precast concrete members due to drying after steam curing.
Even in a prestressed concrete member, cracks may be observed due to excessive unbalanced load. Also,
Even in a viaduct floor plate, fine cracks may occur. Cracks serve as a path for harmful substances to penetrate into the concrete from the external environment, and promote water permeability and neutralization of the concrete material. Therefore, a repair method for closing a crack has been studied and implemented in various fields.

[0003] Conventional repair methods include:
First of all, there is an external shielding by various kinds of coatings since ancient times. There have also been attempts to apply water-reaction curable paints and to impart water repellency to the paints themselves. In recent years, a method of reinforcing by attaching a carbon fiber sheet or injecting a resin or the like into a crack has been attempted. In addition, as an electrochemical method, there is a research report for depositing an inorganic substance similar to a concrete material as an electrodeposit by energizing to crack closure and modify a surface layer portion.

Generally, when cracks occur in the walls or columns of concrete or mortar, rainwater infiltrates along the cracks and causes the steel to rust, or the steel is "delayed" by embrittlement due to hydrogen generated by the rust. I do. To prevent this,
A method has been adopted in which cracks are filled with an adhesive member such as cement from the surface or the surface is further painted to prevent water from entering.

[0005]

However, in the conventional repair method, although there is no problem at the beginning of construction, cracks expand or the adhesive member contracts due to aging over time, and water enters due to the cracks. In addition, the reliability of long-term repair was low, for example, the surface repair member was weathered by rain or ultraviolet rays and fell off. In addition, there has been a problem that regular repair is required, and the cost for this is further increased. Further, the effect of preventing deterioration caused by hydrogen caused by water, such as delayed fracture of a reinforcing bar in a prestressed concrete column represented by an electric pole, was not obtained. Also, the medium that carries harmful substances to concrete materials is mainly water, and water itself can be a factor that promotes corrosion of reinforcing bars, for example.
It is necessary to prevent water from entering the cracks in the concrete material.

[0006] The present invention has been made in view of the above points, and provides a method for repairing cracks in concrete material, which can prevent water intrusion and can maintain the prevention effect.

[0007]

A method for repairing a crack in a concrete material according to the present invention comprises, in the method for repairing a crack in a concrete material, filling a cracked portion of the concrete material with a repair member having a property of absorbing water and swelling. Features.

The method for repairing a crack in a concrete material according to the present invention is characterized in that, in the method for repairing a crack in a concrete material, a water-absorbing material is applied or filled on a surface or a fractured portion of the concrete material.

The method for repairing cracks in a concrete material according to the present invention is characterized in that, in the method for repairing cracks in a concrete material, a resin containing a water-absorbing material is applied or filled on a surface or a fractured portion of the concrete material.

The method for repairing cracks in a concrete material according to the present invention is characterized in that, in the method for repairing cracks in a concrete material, a rust-preventive oil containing a water-absorbing material is applied or filled on the surface or the fractured portion of the concrete material.

The method for repairing a crack in a concrete material according to the present invention is a method for repairing a crack in a concrete material, wherein a repair member having a property of swelling when wetted is applied to a surface or a broken portion of the concrete material immediately before application or the like. It is characterized in that the repair member is mixed with a medium for infiltration, made into a colloidal form, and applied or filled to penetrate the object.

Further, the method for repairing a crack in a concrete material according to the present invention is a method for repairing a crack in a concrete material, wherein the foam is formed on a surface or a fractured portion of the concrete material by a chemical reaction with water to have an expanded volume and elasticity. The repairing member having the above is mixed with a medium for penetrating the repairing member immediately before coating or the like, colloidally applied or filled, and then penetrated into the object.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The method for repairing cracks in concrete material according to the present embodiment is characterized in that a cracking portion (separation portion) of concrete material is filled with a repairing member which absorbs water and swells, and water is cracked. This is a method of prolonging the life by preventing a certain amount of water flow (water intrusion) when the water enters the water. The repair method is based on infiltrating a repair member in a colloidal state into a cracked portion of a concrete material.

The repair members used for repair include (1) those which swell when hydrated (fibrous members such as agar and diaper absorbent), and (2) foaming or expanding in volume due to chemical reaction with water and elasticity. Certain ones (such as urethane foam) are used.
The size of the colloid (powder, thin plate, needle) is smaller than the crack to be repaired. In addition, the carrier (water, alcohol, alkaline water, resin, rust-preventive oil, etc.) and the repairing member, which are the media for penetrating the repairing member into the crack, are mixed immediately before the penetration into the crack and swell after the penetration. Or promote foaming.

There are various types of cracks, from very fine ones to those that can be clearly recognized, but cracks judged to be deteriorated have an opening width (gap) of 0.
It is said to be 1 mm or more. Cracks of 0.1 mm or more can be visually confirmed, and repair according to the present invention is possible.

Examples of the repairing member that absorbs water and swells include a water-absorbing polymer typified by a commercially available absorbent article for disposable diapers. A similar material is mixed with an anhydrous solvent or resin to crack. An appropriate amount is applied or injected / filled around or around the crack site including the site. The water-absorbing and swelling substance applied or filled on the cracked surface or inside, for example, absorbs water if water enters from the gap of the filled resin and swells further, so it acts to stop further intrusion of water from outside .

[0017] The cracks do not always have the same clearance, and in some cases, it is assumed that the cracks may spread further or cracks may occur at other locations. Even in such a case, by allowing an appropriate amount of the water-absorbing and swelling substance to be present on the surface or inside of the concrete material, it is possible to absorb the water that has entered due to the occurrence of cracks and their opening. Conversely, when dried, the water-absorbing swelling material shrinks, thereby increasing air permeability and promoting drying inside the crack.

The method of applying or injecting / filling the repair member can be selected and carried out according to the object to be applied, such as spraying, airless spraying, injection using a tool (such as a syringe), or brushing. . In addition, as the water-absorbing and swelling substance used as the repair member, an environmentally friendly substance utilizing natural resources such as cellulose can be selected. Further, as a solvent or a resin to be mixed with the water-absorbing swelling substance, an epoxy resin, foamed polyurethane or the like having good permeability to the clearance may be selected. Alternatively, it is also possible to use a rust preventive oil or the like to add a rust preventive action to the reinforcing steel.

The repair is performed in the depth direction along the crack. Therefore, the influence of deterioration due to sunlight, wind and rain is small.
Further, the repair member is mixed with a medium for penetrating the repair member, and is made into a colloid to penetrate the crack. By doing so, it is possible to penetrate deep into the cracks by capillary action, and work can be easily performed by brushing, spraying, pouring, or the like. In addition, there is no prior curing work until solidification and drying compared to cement bonding members and painting,
Efficient and economical.

An embodiment (construction example) according to the present invention will be described below.

[Example 1] Cracks in a utility pole made of prestressed concrete (the crack opening width is 0.1 mm on average)
2 mm), a fine powder of a water-absorbing swelling material containing cellulose as a main component was mixed with a main component of a two-part foamed polyurethane resin, jetted out together with a curing agent, and sufficiently injected. Under the condition that almost the same cracks occurred in the adjacent electric poles, five sets of the electric poles subjected to the above treatment and the electric poles not subjected to the treatment were set. While all of the five treated electric poles remained in a healthy state, three of the five untreated telephone poles exhibited further increased cracking and breakage of the rebar. Thereby, the effectiveness of the present invention was confirmed.

[Example 2] In the same manner as in Example 1, two powders of a fine powder of a water-absorbing and swelling material containing cellulose as a main component were applied to the cracks (crack opening width: 0.2 mm on average) of a utility pole made of prestressed concrete. The mixture was mixed with the main component of an epoxy resin, and was spouted out together with the curing agent, followed by sufficient injection. Under the condition that almost similar cracks occurred in adjacent power poles in a cold region, five sets of power poles subjected to the above-mentioned treatment and non-implemented power poles were set. While all the five treated poles remained healthy, four of the five untreated poles had cracks due to frost damage and lack of concrete. Thereby, the effectiveness of the present invention was confirmed.

[Example 3] On a concrete tunnel wall surface, a portion where a large number of cracks having a crack opening width of 0.2 to 1 mm are observed is divided into areas of 4 m ^{2, and} a range in which repair according to the present invention is performed. And a range not to be repaired. The repair was carried out by mixing a fine powder of a water-absorbing swelling material containing cellulose as a main component at the cracked portion with a two-component foamed polyurethane base material, squirting it together with a curing agent, and sufficiently injecting it. After that, in the area where the repair was performed, the condition was healthy, but in the area where the repair was not performed, the concrete wall surface fell. Thereby, the effectiveness of the present invention was confirmed.

As described above, the present invention can be widely applied to the prevention of the collapse of concrete utility poles, the prevention of falling of tunnel walls and concrete walls for preventing landslides, and other uses for preserving concrete structures. FIG. 1 is a schematic diagram comparing a deterioration prevention effect process (a) according to a conventional method with a deterioration prevention effect process (b) of an embodiment according to the present invention. As shown in this figure, it can be seen that the repair method according to the present invention has a very excellent effect as compared with other repair methods.

[0025]

As described above in detail, according to the present invention, it is possible to prevent water and a deterioration accelerating substance from penetrating into the deep portion of the disconnected portion from the cracked portion of the concrete material. Accordingly, it is possible to suppress the effect of crack expansion caused by freezing (ice) of water at the disconnection portion, and to prevent water and the corrosion promoting substance from reaching the reinforcing bar. That is, according to the present invention, it is possible to prevent the deterioration of the concrete member, prolong the life of the reinforcing bar rupture, and reduce the damage caused by frost damage. Further, it is possible to prevent water from entering along cracks for a long time, prevent hydrogen embrittlement and corrosion of the reinforcing bar caused by water, and suppress progress of deterioration of the reinforcing bar.

Further, even if the crack (separation portion) is enlarged, the repairing member swells and closes the crack because a swellable or elastic repairing member is used. Therefore, even if the cracks increase due to aging, the effect of preventing water intrusion is maintained and the effect is maintained. As a result, deterioration of the reinforced concrete due to deterioration of the reinforcing steel can be suppressed.

Further, since the repairing member is mixed with a medium for penetrating the repairing member and applied or filled in a colloidal state, the repairing member can penetrate deep into the cracks by capillary action, and can be brushed and sprayed. The work can be easily performed by a method such as injection or the like. Further, unlike the cement bonding member and the coating, the curing work before or until solidification and drying is not required, so that it is efficient and economical.

[Brief description of the drawings]

FIG. 1 is a diagram comparing a conventional method of repairing (a) with a repairing method (b) of the present invention for preventing deterioration of concrete material.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akinori Watanabe 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo F-term in Nippon Telegraph and Telephone Corporation (reference) 2E176 AA01 BB14 BB16

Claims (6)

[Claims] 1. A method for repairing a crack in a concrete material, the method comprising: filling a fractured portion of the concrete material with a repair member having a property of absorbing water and swelling. 2. A method for repairing a crack in a concrete material, the method comprising applying or filling a water-absorbing material to a surface or a rupture portion of the concrete material. 3. A method for repairing a crack in a concrete material, the method comprising applying or filling a resin containing a water-absorbing material to a surface or a fractured portion of the concrete material. 4. A method for repairing a crack in a concrete material, comprising applying or filling a rust-preventive oil containing a water-absorbing material to a surface or a fractured portion of the concrete material. 5. A method for repairing a crack in a concrete material, wherein a repairing member having a property of swelling when wetted is mixed with a medium for penetrating the repairing member immediately before application or the like on a surface or a fractured portion of the concrete material. A method for repairing a crack in a concrete material, characterized in that the material is infiltrated into an object by being applied or filled in a colloidal state. 6. A method for repairing cracks in a concrete material, wherein a repair member having a property of foaming, expanding in volume, and having elasticity is foamed by a chemical reaction with water on a surface or a fractured portion of the concrete material immediately before application or the like. A method for repairing a crack in a concrete material, wherein the repair material is mixed with a medium for infiltrating the material, colloidally applied or filled, and the material is permeated into an object.