JP3437920B2 - Crack repair agent for concrete structure, waterproofing / repairing method, and method for modifying concrete - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a porous concrete structure such as a bridge, a flat roof, an outer wall of a building, which is cracked, and rainwater penetrates from the crack to corrode the reinforcing bar or the concrete. A crack repairing agent and repairing method for concrete structure for preventing the neutralization of
It also relates to a method for modifying concrete.

[0002]

2. Description of the Related Art The above concrete structure is porous and
Cracks are likely to occur in the concrete due to heat shrinkage, dry shrinkage fatal to the concrete, thermal expansion in midsummer, and the like. When the concrete is cracked, rainwater enters the concrete and causes various problems such as explosion of reinforcing bars, accident of rain leak, and generation of ugly efflorescence. As a conventional repair method in such a case, a method of injecting a urethane foam resin, an epoxy resin, a cement-based grout agent, or the like into the crack is generally used.

However, when these repair agents are injected into the cracks of the concrete as a repair process, there is a disadvantage that the cracks cannot be injected unless the crack width is at least 0.3 mm or more. The crack may extend again and the accident may occur again.

As another construction method, there is a method in which a crack is formed in the concrete by inserting a U-shaped or V-shaped groove with an electric cutter and the cut portion is subjected to a sealing treatment. Although this method can be performed at a relatively low cost, it has the drawback that not only the appearance of the earthworm swelling traces appear on the repaired site over time, but the appearance of the building is impaired and the durability is poor.

Further, as a repair method in the case where the existing waterproof layer of a flat roof is broken or the concrete is cracked and rainwater infiltrates to cause a water leakage accident, asphalt waterproofing agents and urethane resin waterproofing are used. There is a method of covering and repairing the entire flat roof with an agent, a FRP resin waterproofing agent, an epoxy resin waterproofing agent, a rubber sheet waterproofing agent, and the like.

However, in the case of this construction method, it is difficult to carry out the construction at a low cost and the construction period becomes long, and there is a drawback that various troubles such as noise troubles, odors and the like occur in the neighborhood, and the waterproof construction is carried out every few years. There is a hassle of having to start over.

Further, as a method of reinforcing the neutralized concrete, there is a method of covering the whole with a coating film, or a method of repairing the concrete of the neutralized portion with mortar so as to repair it.

The inventor of the present invention has previously proposed a method of injecting calcium into cracks, drying and then injecting sodium silicate into the cracks, and then sprinkling water three times or more (JP-A-7-26674). Issue).

According to the invention described in Japanese Patent Application Laid-Open No. 7-26674, calcium is injected into a crack of a concrete to apply an inorganic penetrating waterproofing agent, and after drying, water is applied three times to form a waterproof layer on the crack. Although formed, it has been found to have the following drawbacks.

(1) The aqueous calcium solution injected into the concrete crack is difficult to dry. (2) It is difficult for the calcium aqueous solution to permeate and adsorb to the concrete, and the calcium solution must be injected into the crack several times or more and then the sodium silicate must be injected into the crack. (3) Immediately after injecting an aqueous calcium solution into the concrete cracks, and then injecting sodium silicate immediately, the reaction occurs on the concrete crack surface to form crystals, and the infiltration of rainwater is sufficient. Cannot be prevented.

[0011]

As described above, since there are many problems in the conventional crack repairing method for the concrete structure, the present invention does not have such a problem.
An object of the present invention is to provide a crack repairing agent for a concrete structure and a repairing method that can repair cracks in the concrete structure and prevent water leakage at a low cost with a short construction period.

Another object of the present invention is to provide a method for modifying a concrete for easily and surely modifying the neutralized concrete to maintain its strength.

[0013]

DISCLOSURE OF THE INVENTION The present invention is a crack repair agent for concrete structure, characterized in that 1% to 60% of alcohol is added to an aqueous solution of 1% to 25% of calcium salt, or By injecting a solution obtained by adding alcohol to an aqueous solution of calcium salt into the cracks of the concrete structure, the calcium salt is rapidly dried by the action of the alcohol, and a crystal form of the calcium salt is formed to form the crystal. A concrete characterized in that the crack is filled with a body.
Repairing method for cracks of structure, or applying or injecting the above-mentioned repairing agent to neutralized concrete and adsorbing it in the cavity of porous concrete, and then applying alkali silicate to make it porous. The above-mentioned problems have been solved by a method for modifying a concrete characterized in that a calcium salt crystal is formed in a cavity of the concrete to densify the concrete to maintain its strong alkalinity.

The calcium salt used in the present invention is currently used as a raw material for medicines, a textile printing agent, an organic synthetic catalyst, a food preservative, and the like, and is not a chemical used for construction. It includes molcarboxylic acids such as acetic acid, formic acid, and lactic acid, dicarboxylic acids such as tartaric acid, apple acid, and succinic acid, polycarboxylic acids such as citric acid, and fatty acids such as balmitic acid and stearic acid, and organic acid calcium. This calcium salt has a problem that it is difficult to dissolve it in alcohol. As calcium lactate, which is a type of calcium salt, is dissolved in water and is often used in foods, it can be said that calcium salt is a safe drug depending on how it is used.

Cement, which is widely used in the construction and civil engineering industry today, contains a large amount of calcium, and the strength of the structure is maintained by maintaining strong alkalinity. However, the current situation is that the concrete becomes neutral due to aging, and rainwater penetrates through the cracks to deteriorate the concrete. If calcium is contained in the cement component, the defect can be easily repaired by alternately supplying the calcium salt and the alkali silicate to the deteriorated portion.

From the above findings, the present inventors have found that 1% to 25%
Using a repairing agent in which 1% to 60% of alcohol is added to the calcium salt aqueous solution, a construction method is proposed to prevent the intrusion of rainwater by filling the water channels leaking from inside the concrete cracks with calcium salt crystals. I put it out.

The feature of the present invention is to dissolve the calcium salt in water and add the alcohol. Calcium salt cannot be dissolved in alcohol, and if it is dissolved in water and used as it is for cracking of concrete, it takes a long time to dry, and a lot of time is required until the water blocking effect is exhibited.

The crack repairing agent for the concrete structure according to the present invention first comprises 1% of calcium salt per 1 liter of water.
-25% is mixed and dissolved, and then 1% to 60% of alcohol is added to the dissolved calcium salt aqueous solution, and the mixture is mixed and stirred to produce. In this case, if 60% or more of alcohol is added, crystallization occurs during stirring and mixing, and injection into cracks of concrete becomes impossible.

The addition of alcohol is for improving the permeability into the interior of the concrete structure and for facilitating the drying to improve the workability. This repairing agent for water stop is intended to increase the speed of crystallization inside the crack of the concrete structure and to simplify the water stop work.

As described above, when a static aqueous solution having a high alcohol concentration is injected into a concrete crack, if the calcium salt crystallizes quickly, the calcium salt does not reach the inner part of the crack and is crystallized around the entrance, A situation occurs where rainwater cannot be prevented. However, the repairing agent according to the present invention is blended in the cracks of the concrete so as to be dried about 30 minutes after being injected, and by repeatedly injecting this stopping aqueous solution , the concrete is repaired only with this stopping aqueous solution. Water leakage from cracks in the structure can be prevented.

[0021] Preferably, after the crystal of the repair agent is formed in the crack of the concrete structure, in order to improve the durability of the water blocking effect, the alkali silicate is re-applied and injected to complete the treatment. The inside of the crack of the concrete structure is filled with the water and the water is stopped to prevent the intrusion of rainwater. Since the crystalline substance of calcium salt is PH8, it is made into a solution that maintains the strength of the concrete by making it a strong alkali with an alkali silicate.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a method for repairing cracks that occur in walls, floors, etc., which are concrete structures. The concrete structure has a fate that cracks occur due to heat shrinkage, dry shrinkage, thermal stress, and the like, and rainwater leaks from the cracks, resulting in a decrease in the life of the concrete. However, according to the present invention, that problem can be solved.

In the example shown in FIG. 1, the concrete structure 1
Rainwater has infiltrated into the crack 2 that has occurred, and water has leaked from the infiltrated portion of the crack 2. In the repair method according to the present invention,
The crack 2 is filled with the repairing agent according to the present invention and waits for it to dry. Since the repair agent is an aqueous solution of calcium salt to which alcohol is added, the drying time is about 30 minutes, which is shorter than before.

When alkali silicate is injected into the crack 2 of the concrete structure 1 after drying, the crystal body 3 is formed in about 1 to 20 minutes, and the crack 2 is filled with the crystal body 3 to the inside and rainwater is filled. It will not pass. After the above treatment, clean water is again sprayed around the cracks 1 or more times to allow the concrete to adsorb the solution so as to permeate it, and the waterproofing power is enhanced to complete the work.
Alternatively, the alkali silicate may be injected first, and then the repair agent may be injected.

Conventionally, when an aqueous solution of calcium was injected into the cracks of the concrete structure 1, a drying time of 24 to 48 hours was required. In addition, when an alkali silicate is injected into a crack in a state where the calcium salt is not dried, a crystal body is formed at the entrance of the crack and the solution of the calcium salt and the alkali silicate are used to fill the inside of the crack of the concrete. The solution was alternately repeated several times.

The greatest feature of the present invention is to use a calcium salt containing alcohol. By injecting the repair agent or alkali silicate into the crack 2 of the concrete structure 1 to 2 times, coating and drying the same, the inside of the crack 2 can be completely removed if the crack width is 0.1 mm to 2 mm. Can be buried in and can not accept rainwater. The penetrating force and volatilizing force of the alcohol penetrate deep into the crack and adsorb it into the cavity of the porous concrete to form a crystal. Working time is reduced to about 2 hours. Moreover, unlike the conventional resin-based injection method, the crystal does not cause secondary damage (regeneration of crack expansion) to the concrete, and the construction can be easily performed.

Complete repairs are required for waterproofing work, water-stopping work, etc. However, by using alkali silicate as an auxiliary agent and performing watering treatment once or more, permanent cracking of the concrete structure 1 Can be waterproof and waterproof. The water sprinkling treatment is performed once or more because it is permeated deep into the concrete, and the alkali silicate and calcium hydroxide (free calcium) in the concrete cause a chemical reaction to be crystallized to form a porous structure. This is because the concrete is densified to improve the concrete and prevent intrusion of rainwater twice.

FIG. 2 shows an example of repair work on a concrete roof, where 11 is a concrete frame, 12 is a parapet, 13 is a waterproof layer, 14 is a heat insulating material, 15 is a shrink joint, and 16 is A pressing concrete, 17 is a concrete slab, 18 is a concrete crack, and 19 is a broken portion of the waterproof layer. Waterproof layer 1 on this concrete rooftop
When a breakage portion 19 is formed in 3 and water leaks into the room from the crack 18 of the concrete, the conventional pressing concrete 1
6 is removed and the broken portion 19 of the waterproof layer 13 is additionally attached to repair it, and the pressing concrete 16 is re-stripped again, or
The entire rooftop was repaired by applying a waterproof film on the roof.

However, in the present invention, after the contraction joint 15 shown in FIG. 2 is removed and cleaned well, the steps of alternately applying and injecting an aqueous solution of alkali silicate and calcium salt containing alcohol thereinto are carried out. This is repeated a number of times to form crystals in the gaps of the pressing concrete 16 to prevent rainwater from entering. This construction method will be described in more detail below.

(1) An aqueous solution of calcium salt containing alcohol is poured into the shrinkage joint 15 and waits for drying (drying time 30
Minutes to 1 hour). (2) After the step (1) is completed, alkali silicate is shrunk joint 1
5 and wait for calcium salt crystals to form (2-4 hours). (3) After the step (2), the fresh water sprinkling process is performed once or more around the contraction joint 15 to complete the process.

The solutions (1) and (2) enter the gap of the pressing concrete 16 and reach the crack 18 of the concrete through the breakage portion 19 of the waterproof layer. The injected aqueous solution spreads over the gaps between the pressing concrete 16 and the entire inside of the concrete cavity, and the pressing concrete 1
By filling the inside of the space between 6 and the waterproof layer 13 with a crystal, a rooftop where rainwater does not enter is obtained.

The reason why the aqueous solution of the calcium salt containing alcohol is used in the above method is that the drying time of the aqueous solution is short. Conventionally, it took 24 to 48 hours or more even in fine weather until calcium is dissolved in water and poured into the shrinkage joint 15 of the pressing concrete and dried to form a crystal body. Then it is halved.

1% alcohol in an aqueous solution of calcium salt
By adding up to 60%, the water contained in the solution is volatilized at the same time by the volatility of the alcohol, which simplifies the work and makes it possible to inject the alkali silicate in a short time. Crystals are rapidly formed in the 16 gaps to form a perfect waterproof protective layer.

Next, the reason why the aqueous solutions of alkali silicate and calcium salt containing alcohol are used alternately will be described.

The calcium salt is weakly alkaline at PH8. Concrete becomes weak because it is neutralized. Therefore, in order to maintain the strength of the concrete, its strong alkalinity may be maintained. there,
Injecting a weakly alkaline solution of PH8 may promote neutralization. In the present invention, in order to maintain the performance of the concrete, when an aqueous solution of a calcium salt is used, after the injection, a drying time is allowed to inject the alkali silicate into the place to restore the PH to 12% or more. Preserve concrete.

Further, according to the present invention, when the aqueous solution of calcium salt permeates into the cavity of the porous concrete by the osmotic force of alcohol and azeotropy, the aqueous solution of alkali silicate is injected into the portion to be crystallized. The body can be made and the porous concrete can be transformed into a non-porous concrete.

Next, the principle of the rooftop concrete waterproofing method will be described. Normally hold down concrete 16
There is a pool of rainwater on the back side of this, and because this rainwater is in contact with the holding concrete 16, calcium hydroxide ( Ca (OH) ₂ ) in the concrete flows out, and the holding concrete 16 The flowing out calcium hydroxide ( Ca (OH) ₂ ) is filled below. This calcium hydroxide reacts with the injected alkaline silicate aqueous solution to form a crystalline body, which makes it possible to waterproof.

[0038]

[Chemical 1]

[0039]

[Chemical 2]

[0040]

In the case of waterproofing by the above method, the residual amount of free calcium has a great meaning. Hold down concrete 16
If there is a large amount of residual free calcium accumulated on the back of the,
Crystals are formed only by injecting an alkaline silicate aqueous solution to form a waterproof layer, but when the residual amount of free calcium is small, it is necessary to supplement calcium. This phenomenon also occurs inside the concrete crack. In order to close the cracks in the concrete, the injection amount of the calcium salt aqueous solution into the cracks, the drying time, the time until crystallization, etc. are important factors.

When preparing an aqueous solution of 1% to 25% calcium salt, it is better to use distilled water. If dissolved in normal tap water, mold is likely to occur in summer. Powder of calcium salt is often used in foods, pharmaceuticals, etc.
When it is used for concrete cracks, it is preferable to use a powder having coarse mesh as much as possible. This is because a coarser mesh is more likely to be adsorbed on the fracture surface (concrete bubbles) inside the concrete crack. When an aqueous solution of fine particles of calcium is injected into the concrete crack, it may flow out from the injected lower end, and after the water stop treatment with calcium crystal inside the concrete crack, as time passes, Water leakage accidents often occur.

The method of the present invention is characterized in that calcium salt crystals are formed inside the cracks of the concrete to stop water and prevent rainwater from leaking from the cracks of the concrete. However, another feature is that crystals formed in the cracks of the concrete absorb rainwater, and more water than the absorbed rainwater cannot be accepted due to surface tension.

As described above, when the calcium salt particles are fine particles, a crystal is formed over the entire crack of the concrete, and when the natural drying is repeated, the crystal is cracked and water begins to leak. There is.

It is preferable to dissolve 15% to 30% of alkali silicate in water and adjust the pH to 12 or less before use. Originally, alkali silicate has a specific gravity of 1.4 and a pH of around 13, and if the specific gravity is heavy, it hardly penetrates into the concrete, and does not enter the concrete crack when chemically reacting with an aqueous solution of calcium salt.

Next, the reason for adding alcohol to calcium acetate will be described. Calcium salts are soluble in water but poorly soluble in alcohol. Therefore, make a 1% to 25% aqueous solution of calcium salt and add alcohol to it.
Is added 1% to 60% of ethanol . Ethanol evaporates at a boiling point of 78.3 degrees, and water is azeotroped together with the evaporation of ethanol , and water of an aqueous solution of calcium salt also evaporates at the same time, so that the drying speed is fast and the workability is excellent. Was confirmed.

In order to rapidly dry the rainwater or the calcium salt aqueous solution accumulated inside the concrete cracks,
Heat is required. It is an object of the present invention that by adding alcohol to an aqueous solution of calcium salt, the solution injected into the crack of the concrete and the accumulated water are azeotroped together. Normally, when calcium is injected inside the crack of the concrete or inside 6 of the holding concrete,
The drying required 24 to 48 hours or more, but the addition of alcohol succeeded in shortening the drying time.

Regarding the compounding ratio when alcohol is added to an aqueous solution of calcium salt, 1% to 48% is a range in which it can be easily dissolved, and 49% to 60% gives some crystals. These crystals disappear with stirring and become a normal solution.
When 60% or more of alcohol is added, there is a feature that crystallization occurs during compounding.

Further, since the alcohol penetrates into the hollow (porous) of the concrete together with the aqueous solution of the calcium salt, the crystal formation of the waterproof layer becomes easy.

The above examples are merely examples of many embodiments of the present invention, and the present invention is not limited to the above-described repair of cracks, but also secondary product of concrete (a hum tube, a box carbur, It can also be applied to reinforcement of blocks), reinforcement of concrete roads, breakwaters, levees, bridges of electric trains, and repair of cracks.

[0051]

As described above, according to the present invention, by adding alcohol to an aqueous solution of calcium salt, a concrete
The calcium salt aqueous solution is sufficiently adsorbed on the cracked or neutralized porous concrete of the glass structure, and the crystal body is rapidly formed inside the concrete by the chemical reaction using the alkaline silicate aqueous solution and water. It is something that makes it workable,
The cost can be reduced, and the most suitable construction method and repair agent to prevent water leaking from cracks in today's concrete structures can be obtained, and at the same time, neutralization of concrete can be prevented. It has the effect of maintaining its strength.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a construction method according to the present invention.

FIG. 2 is a schematic diagram for explaining a construction method according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) E04G 23/02 C04B 41/68

Claims (6)

(57) [Claims] 1. An aqueous solution containing 1% to 25% of calcium salt,
In order to accelerate the drying, 1% to 60% of alcohol is added , and the calcium salt is acetic acid, formic acid, lactic acid, etc.
Dicarboxylic acid such as molcarboxylic acid, tartaric acid, apple acid, succinic acid, etc.
Polycarboxylic acids such as boric acid and citric acid, or balmitic acid
Organic acids such as fatty acids such as acid and stearic acid
Crack repair agent for concrete structure which is sium . 2. An aqueous solution containing 1% to 25% of calcium salt,
1% to 60% of alcohol is added to accelerate the drying, and the calcium salt is acetic acid or ant.
Acids, carboxylic acids such as lactic acid, tartaric acid, malic acid, succinic acid
Dicarboxylic acids such as, polycarboxylic acids such as citric acid,
Is one of the fatty acids such as barmitic acid and stearic acid.
Of Cracks in Concrete Structures of Organic Calcium Oxide
Method of manufacturing agent. 3. A solution obtained by adding alcohol to an aqueous solution of calcium salt is injected into the cracks of the concrete structure, whereby the solution is rapidly dried by the action of the alcohol and a crystal form of calcium salt is formed. A method for repairing a crack in a concrete structure, which comprises filling the crack with the crystal body. 4. The repair agent according to claim 1 is applied to or injected into the cracks of the concrete structure, and after drying, an aqueous solution of alkali silicate is injected to rapidly form a crystalline body of calcium salt. A method for repairing a crack in a concrete structure, which comprises filling the crack with a body. 5. A calcium salt aqueous solution to which an alcohol is added in order to promote its drying is permeated and adsorbed into a porous concrete or stone material, and an alkali silicate is applied to the solution, followed by drying. A waterproofing method characterized in that cracking is prevented by water-spraying the part once or more to make the concrete or stone material non-porous. 6. The neutralized concrete is coated or injected with the repair agent according to claim 1 to be adsorbed in the cavities of the porous concrete, and then alkali silicate is coated to make the porous concrete. A method for modifying a concrete, characterized in that a crystal of a calcium salt is formed in a cavity of the concrete to densify the concrete to maintain its strong alkalinity.