JP4515328B2 - Concrete repair method - Google Patents

Description

  The present invention relates to a method for repairing concrete. In particular, the present invention relates to a method for repairing concrete, characterized in that an alkali metal silicate aqueous solution is pressed into an injection hole drilled in a cracked concrete surface.

  Cracks (cracks) occur in concrete after hardening due to various factors. For example, shrinkage during curing, repeated expansion and contraction due to temperature changes, deformation due to load, and the like are the main causes of cracking. The cracks generated in this way may reduce the strength of the concrete itself or cause water leakage. In addition, moisture and air that has penetrated from the cracks may corrode the internal reinforcing bars, or the concrete around the cracks may react with carbon dioxide and become neutral, reducing strength. If a crack once generated is left as it is, the crack grows and the problem may become more serious. In particular, if the water leakage location is left as it is, the amount of water leakage will gradually increase and the strength will decrease, so an effective water stopping method is strongly desired.

  As a method of stopping water leakage from concrete, a method of injecting a water-stopping agent into the crack is widely used. As such a water-stopping agent, various inorganic water-stopping agents and polymer water-stopping agents are used. As a typical inorganic water-stopping agent, cement paste using fine particle cement is used, but it is not easy to repair even fine cracks. For example, if the inner surface of the crack is dry, the moisture of the cement paste is deprived and the fluidity decreases, so the cement paste may not reach the depth of the crack, and conversely, the inner surface of the crack is wet In some cases, the cement concentration is lowered and sufficient strength may not be exhibited. On the other hand, a curable resin such as an epoxy resin or a polyurethane resin is used as the polymer water-stopping agent. However, since such a resin generally has a high viscosity, it is difficult to infiltrate into fine cracks, and it has been necessary to apply high pressure to the cracks.

  For example, in Patent Document 1, a concrete crack in which water leakage has occurred is washed with high pressure, and then a sealing material is pressed into a crack other than an injection portion and sealed, and a two-stage drill is used to fix the anchor hole. Squeezed into a two-step shape of a countersink hollow on the head to form an injection hole, and then an inner screw anchor is driven in, and a hollow bolt mounted in the order of silicon rubber, washer and nut is attached to the inner screw anchor, and A concrete water-stop method is described in which a container containing a hydrophilic one-component polyurethane resin is screwed and fixed to a hollow bolt and then reacted with water leakage to foam and harden the resin. Further, Patent Document 2 discloses a sealing method in which a water blocking material injection hole is drilled at a predetermined angle from a concrete surface layer with respect to a water leakage crack of a concrete structure, and the water blocking material is retained in a state of crossing the water leakage crack. Forming a chamber and inserting a crack reinforcing member into the sealed chamber, and then sealing the leakage crack in the concrete surface layer and installing an injection plug with a backflow prevention valve in the water stop injection hole, and then injecting the injection A water-stopping material mainly composed of a hydrophilic one-component polyurethane prepolymer is injected from a plug, and a predetermined amount is filled in the sealed chamber and a water leakage crack, and the water-stopping material is foamed by a chemical reaction with intrusion water. A high-pressure injection water-stop method is described, which is characterized in that it penetrates into a water leakage crack.

  On the other hand, Patent Document 3 describes a method of using a concrete modifier composed of an aqueous solution in which a polyvalent carboxylic acid such as citric acid is dissolved in water glass as a method for repairing fine cracks in concrete. Yes. The modifying agent is used by being applied to the surface of a cracked concrete or injected into a crack, and can be used for concrete waterproofing work or water stop work.

Japanese Patent Laid-Open No. 10-245998 JP 2004-251009 A JP 2001-294461 A

  However, as described in Patent Document 1 and Patent Document 2, when a polymer-based repair agent is used, since the viscosity of the injected resin is high, even if high pressure is applied, fine cracks still occur. It was difficult to repair with sufficient filling. In addition, if an aqueous solution having a low viscosity as described in Patent Document 3 is used, it is considered that the permeability to fine cracks is improved, but it is still possible to sufficiently penetrate to the deep part of the fine cracks. In this case, it may be preferable to inject by applying pressure. However, since it is a low-viscosity and highly permeable liquid, it tends to leak from the side of the injection plug when pressure is applied, and it may be difficult to stably maintain the high pressure. In addition, when a low-viscosity liquid leaks, it is likely to be scattered, which may cause a problem from the viewpoint of worker safety.

  The present invention has been made to solve the above problems, and provides a method for repairing concrete in which a repair agent can be safely and surely infiltrated into fine cracks generated in concrete by applying pressure. It is intended to do.

The above-mentioned problem is that the injection hole is drilled in the cracked concrete surface, the anchor is fixed inside the injection hole, the rod member is fixed to the anchor, and the rod member is fixed to the anchor member. A method of repairing concrete in which an alkali metal silicate aqueous solution pressurized by a pump is injected using an injection plug closely attached to an opening of an injection hole , wherein a pressure gauge is provided between the pump and the injection plug After press-fitting the alkali metal silicate aqueous solution that has been connected and pressurized by the pump, the valve between the pump and the pressure gauge is closed, and the alkali metal silicate aqueous solution is subsequently reduced in pressure. It is solved by providing a concrete repairing method characterized by judging the state of intrusion into the crack of the concrete.

  The alkali metal silicate aqueous solution used here as a repair agent is an aqueous solution having a relatively low viscosity. Further, since pressure is applied during injection, the repair agent can be sufficiently distributed to deep cracks. is there. Moreover, by fixing the anchor inside the injection hole, the injection plug does not come off even when high pressure is applied. Therefore, it is possible to allow the repair agent to penetrate into the deep part of the crack safely and reliably.

At this time, the anchor has an inner thread, the rod-shaped member has an outer thread, is screwed to the anchor, penetrates the injection plug, and tightens a nut through a packing to tighten the nut. The injection plug is preferably in close contact with the opening. It is also preferable that the injection plug has a sealing portion covered with a buffer material, and the sealing portion is inserted into the opening portion of the injection hole to be in close contact .

Buffer containing the air is connected between the injection plug and the pump, after press-fitting the alkali metal silicate solution from said pump to release the connection between the pump and the buffer unit Thus, it is a preferred embodiment of the present invention to continue the injection by the pressure of the compressed air in the buffer unit.

  It is preferable that the pressure at the time of press-fitting the alkali metal silicate aqueous solution is 0.5 to 10 MPa. The alkali metal silicate aqueous solution is also preferably one in which a part of the silicate is neutralized with an acid. Moreover, it is also preferable to press-fit a fine particle cement dispersion or an aqueous solution in which a salt of a metal belonging to Group 2 of the periodic table is dissolved after the alkali metal silicate aqueous solution is injected.

  According to the repairing method of the present invention, the repairing agent can be safely infiltrated into the fine cracks generated in the concrete by applying pressure. It is easy to stably maintain a high pressure and prevent leakage of the repair agent from the side of the injection plug, and is suitably used for water-stopping treatment of concrete in which water leakage has occurred.

  Hereinafter, the present invention will be described more specifically with reference to the drawings. FIG. 1 is a view showing the appearance of an example of an injection plug and its fixing device used in the present invention. FIG. 2 is a schematic cross-sectional view showing a state where the injection plug of FIG. 1 is fixed to the injection hole. FIG. 3 is a schematic view showing an example of the entire injection apparatus. FIG. 4 is a schematic view showing another example of the entire injection apparatus. Hereinafter, the concrete repair method of the present invention will be described with reference to FIGS.

  In the present invention, the liquid used for repairing concrete is an aqueous alkali metal silicate solution. The aqueous solution has an active ingredient dissolved in water, has a high affinity for concrete, and has a low viscosity in many cases. Therefore, the aqueous solution can be easily infiltrated into fine cracks generated in the concrete. Furthermore, by injecting under high pressure, the aqueous solution can be penetrated deeply into fine cracks. On the other hand, since the permeability is high and the viscosity is relatively low, it has a problem that it easily leaks when injected under pressure, and the repair method of the present invention is particularly preferably employed. Alkali metal silicates are believed to react with calcium salts near the concrete surface inside the cracks, especially calcium hydroxide, to form calcium silicate crystals, which is the main component of the calcium silicate. It is considered that the inside of the crack is filled.

Examples of the cation species of the alkali metal silicate include lithium ions, sodium ions, and potassium ions, but sodium ions are preferable from the standpoint of availability and cost. Also, the anion species is not particularly limited, and not only anion species such as orthosilicate anion [SiO ₄ ^4- ] and metasilicate anion [SiO ₃ ^2- ], but also a plurality of silicate [SiO ₂ ] units are linked. In this case, anion species may be formed. Specific examples of the compound include sodium orthosilicate, potassium orthosilicate, lithium orthosilicate, sodium metasilicate, potassium metasilicate, lithium metasilicate, and water glass.

Among these, water glass is preferably used in the present invention. Water glass is an aqueous solution of an alkali metal silicate, in which a plurality of silicic acid [SiO ₂ ] units are connected to form an anionic species. The alkali metal used here may be potassium, but is usually sodium. The general formula for the solid content in the case of sodium silicate is represented by Na ₂ O · nSiO ₂ . The ratio of the number of metal atoms to the number of silicon atoms in the silicate [metal / silicon] is preferably in the range of 0.1-2. When the ratio [metal / silicon] is less than 0.1, the water solubility decreases, and the aqueous solution may not reach the deep part in fine cracks. More preferably, it is 0.2 or more, and further preferably 0.3 or more. On the contrary, when the ratio [metal / silicon] exceeds 2, a large amount of calcium is required for curing, and the curability may be lowered. More preferably, it is 1.5 or less, and more preferably 1 or less.

  The higher the concentration of alkali metal silicate in the aqueous solution, the higher the specific gravity of the aqueous solution. The preferred specific gravity of the aqueous solution is 1.05 to 1.4. By setting it as such a density | concentration, while being able to fully penetrate | deep into the deep part of a crack, sufficient quantity of alkali metal silicate can be supplied to the inside of a crack. The specific gravity is more preferably 1.1 or more, and even more preferably 1.15 or more. On the other hand, it is more preferably 1.35 or less, and further preferably 1.3 or less.

  Moreover, it is preferable that an acid is mix | blended with alkali metal silicate aqueous solution and a part of said alkali metal silicate is neutralized with the acid. By neutralization, the pH of the aqueous solution does not become too high, and calcium carbonate generated on the concrete surface in the cracks is likely to elute, and calcium silicate strongly adhered to the concrete surface is likely to be formed. . The type of the acid is not particularly limited, but the carboxylic acid can be used from the viewpoint that the alkali metal silicate aqueous solution can have an appropriate pH and does not adversely affect the stability of the concrete or the internal rebar. Is preferred.

  The carboxylic acid used is not particularly limited, and monocarboxylic acids such as formic acid, acetic acid and propionic acid; oxymonocarboxylic acids such as glycolic acid, lactic acid and gluconic acid; oxalic acid, malonic acid, succinic acid and pimeline Polyvalent carboxylic acids such as acid, adipic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid; hydroxy polyvalent carboxylic acids such as malic acid, citric acid; acrylic acid polymer, maleic anhydride polymer, etc. The polyvalent carboxylic acid polymer can be used. Of these, oxycarboxylic acids and polycarboxylic acids having low volatility and good water solubility are preferred, and polyvalent carboxylic acids are more preferred. Also suitable are unsaturated polyvalent carboxylic acids such as maleic acid and fumaric acid.

  When the carboxylic acid is blended in the alkali metal silicate aqueous solution, the ratio [metal / carboxyl group] of the number of metal atoms in the silicate to the number of carboxyl groups in the carboxylic acid is preferably 1 to 200. is there. When the ratio [metal / carboxyl group] is less than 1, the water solubility is lowered, and the aqueous solution may not reach the deep part in fine cracks. More preferably, it is 2 or more, more preferably 5 or more, and most preferably 10 or more. Conversely, if the ratio [metal / carboxyl group] exceeds 200, a large amount of calcium is required for curing, and the curability may be lowered. More preferably, it is 100 or less, More preferably, it is 50 or less.

  The alkali metal silicate aqueous solution may contain other components as long as the effects of the present invention are not impaired. However, it is preferably a uniform aqueous solution substantially free of insoluble components. By doing so, it becomes easy for the aqueous solution to penetrate to the deep part of the fine crack.

  The concrete 10 is repaired by injecting the repair agent composed of the alkali metal silicate aqueous solution described above. In the repair method of the present invention, an alkali metal pressurized by a pump 40 using an injection plug 20 in which an injection hole 12 is drilled in the surface of the concrete 10 where the crack 11 has occurred and is in close contact with the opening of the injection hole 12. Press-fit silicate aqueous solution. At this time, the injection hole 12 is preferably formed at a position that penetrates the crack 11.

  The injection plug 20 is formed of a substantially T-shaped tubular body, and has an upper opening 21, a lower opening 22, and a side opening 23. A sealing portion 24 is formed in the vicinity of the lower opening 22, the sealing portion 24 has a tapered shape that tapers downward, and the surface thereof is covered with a buffer material 25. The sealing part 24 is inserted into the injection hole 12 drilled in the surface of the concrete 10 and seals the opening of the injection hole 12 through the buffer material 25. As a result, it is possible to ensure sealing. The material of the injection plug 20 is a hard material such as metal. As the buffer material 25, flexible rubber or resin is used. For example, a rubber tube or a soft vinyl tube may be covered, or a vinyl tape or a Teflon (registered trademark) tape may be wound.

  The upper opening 21 and the lower opening 22 of the injection plug 20 are connected in a straight line, and the rod-shaped member 30 penetrates the inside thereof. The rod-shaped member 30 has external threads formed on the entire surface, and an anchor 31 is screwed to the lower end portion thereof. The anchor 31 has an internal thread and is screwed to the external thread of the rod-shaped member 30. Four cuts 33 are made in the lower end 32 of the anchor 31, and when the wedge 34 is driven, the lower end 32 is opened and pressed against the inner wall of the injection hole 12. The wedge 34 is pressed against the bottom 13 of the injection hole 12 and the upper end of the bar is hit with a hammer or the like through the bar to open the lower end 32 and fix the anchor 31 to the injection hole 12. By screwing the member 30 to the anchor 31, the rod-shaped member 30 can be securely fixed to the injection hole 12. The rod-shaped member 30 can also be fixed to the injection hole 12 by screwing the anchor 31 to the rod-shaped member 30 in advance and then hitting the upper end 35 with a hammer or the like. The anchor 31 is not particularly limited as long as it can be fixed in the injection hole 12, and various types of anchors can be used.

  A nut 36 is screwed from above the rod-shaped member 30 such that the rod-shaped member 30 screwed to the anchor 31 fixed to the injection hole 12 penetrates the inside of the injection plug 20. Then, the nut 36 is pressed against the upper opening 21 of the injection plug 20 through the packing 37 and tightened. Thereby, the space between the upper opening 21 and the nut 36 is strongly sealed, and the space between the opening of the injection hole 12 and the sealing portion 24 is also strongly sealed. Since the anchor 31 is strongly fixed in the vicinity of the bottom 13 of the injection hole 12, even when the repair agent is injected under a high pressure, the injection plug 20 does not come off or the repair agent does not leak. Therefore, it becomes possible to apply a high pressure, and it becomes possible to inject the repair agent into the fine cracks. The packing 37 is not limited as long as it has appropriate flexibility and can be sealed, but an O-ring is preferably used. Further, since the rod-shaped member 30 penetrates the injection plug 20, the rod-shaped member 30 can be easily applied to the injection hole 12 of any depth if the length of the rod-shaped member 30 is roughly adjusted. In the vicinity of the injection plug 20, the crack 11 appearing on the surface of the concrete 10 is preferably sealed prior to the injection operation. The sealing method is not particularly limited. For example, the sealing is performed by application of an alkali metal silicate aqueous solution or sliding of a fine particle cement paste.

  The side opening 23 of the injection plug 20 is a female portion of the joint 46, and the male portion of the joint 46 can be detachably connected and fixed. A check valve is provided inside the female portion constituting the joint 46 so that the repair agent does not leak when the connection is released. Such a leakage prevention valve is not limited to the check valve, and a manual valve or the like can also be used. The repair agent pressurized by the pump 40 is supplied through the side opening 23. The repair agent passes through the inside of the joint 46 and is pressed into the injection hole 12 from the clearance 26 existing outside the rod-shaped member 30 in the injection plug 20. Since the repair agent can be supplied from the vicinity of the inlet of the injection hole 12, it is easy to spread the repair agent over the entire injection hole 12, and the repair agent can be used at any position in the injection hole 12. Easy to enter.

  Although the pressure at the time of press-fitting the alkali metal silicate aqueous solution is not particularly limited, it is preferably 0.5 to 10 MPa. In the case of a pressure of 0.5 MPa or less, the repair agent may not reach the deep part of the fine crack. Further, since the aqueous solution pressure is not so high, there are many cases in which the injection plug 20 does not come off or liquid leakage occurs even if the configuration of the present invention is not adopted, so the benefit of employing the repair method of the present invention is not so great. . More preferably, it is 1 MPa or more, and further preferably 1.5 MPa or more. On the other hand, in the case of a pressure of 10 MPa or more, there is a risk of damaging the concrete, and the pressurizing device becomes large. More preferably, it is 5 MPa or less, More preferably, it is 3.5 MPa or less. In the pressurizing operation, it is preferable to gradually increase the pressure while confirming the injection state. The pump 40 for pressurization is not particularly limited, and various types can be used, and a tank 41 for storing a liquid to be supplied to the pump 40 is connected.

  In the example of FIG. 3, a unit 44 having a valve 42 and a pressure gauge 43 is detachably connected by joints 45 and 46 between the pump 40 and the injection plug 20. With such a configuration, the alkali metal silicate aqueous solution pressurized by the pump 40 is injected, and then the valve 42 between the joint 45 and the pressure gauge 43 is closed. It is possible to determine the state of penetration of the metal silicate aqueous solution into the crack. In the past, injection operations that depended on the instinct of the site were often performed. However, it is possible to quantitatively determine the situation of actual supply into the cracks, and to perform highly reliable repair work.

  In the example of FIG. 4, a unit 48 having a buffer part 47 containing air and a valve 42 is detachably connected between the pump 40 and the injection plug 20 by joints 45 and 46. By adopting such a configuration, after the alkali metal silicate aqueous solution pressurized by the pump 40 is injected, the valve 42 between the joint 45 and the buffer portion 47 is closed, and then the connection of the joint 45 is released. Then, the injection by the pressure of the compressed air in the buffer unit 47 can be continued. When it takes a long time to inject the aqueous solution into the crack, the injection operation from a large number of injection plugs 20 can be performed in parallel with one pump 40, and the work efficiency is improved. A pressure gauge 43 indicating the pressure inside the buffer unit 47 is preferably provided in the buffer unit 47. Thereby, when the pressure drop is recognized, it can be connected to the pump 40 again and the pressurization can be repeated. The buffer portion 47 is not particularly limited as long as it contains air and has pressure resistance, and may have a tank shape or a simple pipe shape. The valve 42 may be manually closed or may be a check valve that automatically closes when the connection is released.

  The unit 44 used in FIG. 3 and the unit 48 used in FIG. 4 may be used for one injection hole 12, or one of them may be used, or neither of them may be used. May be. Corresponding to the situation of cracks to be repaired, etc., it is possible to select an appropriate work while recombining the units by appropriately judging at the site. When both units 44 and 48 are used, they may be connected in series and used at the same time, or may be switched and connected in sequence.

  Even if the operation of injecting the alkali metal silicate aqueous solution in the manner as described above is still not possible to close the crack, after pressing the alkali metal silicate aqueous solution, from the same injection plug 20, Subsequently, it is preferable to inject a fine cement dispersion or an aqueous solution in which a salt of a metal belonging to Group 2 of the periodic table is dissolved. Alkali metal silicate aqueous solutions can penetrate into fine cracks, but cannot fill cracks that are too wide. On the other hand, it is possible to fill a wider crack by press-fitting a fine particle cement dispersion or an aqueous solution in which a metal salt belonging to Group 2 of the periodic table is dissolved.

When injecting the fine particle cement dispersion, the presence of the alkali metal silicate promotes the hardening of the fine particle cement, so that wide cracks are easily blocked. The fine particle cement used here has a specific surface area measured based on JIS R5201 of usually 5000 cm ² / g or more, preferably 8000 cm ² / g or more, and more preferably 10,000 cm ² / g or more. is there. The specific surface area is usually 30000 cm ² / g or less, and preferably 20000 cm ² / g or less from the viewpoint of availability. In addition, the specific surface area of normal Portland cement is usually about 2500-3300 cm < ² > / g. A cement having a specific surface area of 8000 cm ² / g or more is sometimes referred to as an ultrafine particle cement. The content of fine particle cement in the fine particle cement dispersion is preferably 33 to 67% by weight. When the content of the fine particle cement is less than 33% by weight, the strength of the cured product may be insufficient, more preferably 50% by weight or more, and even more preferably 55% by weight or more. . On the other hand, when the content of the fine particle cement exceeds 67% by weight, the filling property into the cracks may be lowered, and more preferably 63% by weight or less.

  In addition, as described above, alkali metal silicate is considered to react with a salt of a metal belonging to Group 2 of the periodic table such as calcium ions to form calcium silicate crystals. Compared to the case of the fine particle cement dispersion, the penetration into cracks is good, so it is not fine but effective against relatively narrow cracks. Examples of salts belonging to Group 2 of the periodic table include beryllium salts, magnesium salts, calcium salts, strontium salts, barium salts, etc. In view of availability and toxicity, magnesium salts or calcium salts are Preferably used. Of these, magnesium salts are preferred because they are excellent in the effect of quickly closing large cracks. The anionic species of the metal salt belonging to Group 2 of the periodic table is not particularly limited, but carboxylate is preferably used because there are many salts that do not adversely affect concrete and have high solubility in water. Preferred examples of the carboxylate include acetate, propionate, lactate and the like.

  The content of a salt of a metal belonging to Group 2 of the periodic table dissolved in the Group 2 metal salt aqueous solution is preferably 0.01% by weight or more in terms of metal element. This is because when a certain amount or more of the Group 2 metal ions are dissolved, the Group 2 metal ions that can fill the inside of the large crack can be easily provided. The content of the salt is more preferably 0.5% by weight or more, and further preferably 1% by weight or more in terms of metal element. On the other hand, the content of the salt is usually 20% by weight or less in terms of metal element. The group 2 metal salt aqueous solution may contain components other than the salt of the metal belonging to group 2 of the periodic table dissolved therein. When the Group 2 metal salt aqueous solution is a uniform aqueous solution that does not substantially contain insoluble components, it is easy to enter the interior of the crack. The content of the salt in the Group 2 metal salt aqueous solution is preferably 0.5% by weight or more, more preferably 1% by weight or more, and further preferably 2% by weight or more in terms of metal element. It is. Although the Group 2 metal salt aqueous solution may contain an insoluble component, even if the insoluble component contains a Group 2 metal element, the above-mentioned “dissolved metal salt belonging to Group 2 of the periodic table” “Content” shall not be included.

  Either the fine particle cement dispersion or the aqueous solution in which the salt of the metal belonging to Group 2 of the periodic table is dissolved may be injected, or these two types of liquids may be sequentially injected, or the periodic table A liquid in which fine-particle cement is dispersed may be injected into an aqueous solution in which a metal salt belonging to Group 2 is dissolved. It is appropriately selected according to the cracking situation. An injection operation of an aqueous alkali metal silicate solution may be performed again after injecting an aqueous solution in which a fine particle cement or a metal salt belonging to Group 2 of the periodic table is dissolved. Since wide cracks are blocked and high pressure can be applied, an alkali metal silicate aqueous solution can be infiltrated into fine cracks.

  After injecting the repairing agent as described above, the nut 36 is loosened to remove the injection plug 20 from the injection hole 12, and the rod-shaped member 30 is rotated to remove it from the anchor 31. Thereafter, it is preferable to close the injection hole 12 using a super-hard cement or the like. Thereafter, it is also preferable to apply an alkali metal silicate aqueous solution to the concrete surface near the injection hole 12.

  As described above, according to the repair method of the present invention, the repair agent can be safely and surely infiltrated into the fine cracks generated in the concrete. It is also easy to select an optimal crack repair method by combining various methods according to the situation at the site, and a construction method with high work efficiency is provided.

  The repair method of the present invention can be applied to various places and purposes. For example, it is possible to repair cracks generated on the floor, walls, ceiling, etc. of rooftops, verandas, basements, parking lots, etc., and it is particularly effective for water stoppage when water leaks. It is also suitable for repairing junkers and joints in hardened concrete. It is also suitable for stopping water leakage from pools and aquariums while accumulating water.

  Hereinafter, the present invention will be described in more detail using examples. This embodiment shows an example of a method for repairing a crack generated in concrete by injecting an alkali metal silicate aqueous solution using the apparatus having the configuration shown in FIG. 3 or FIG. By this method, water leakage that occurred in concrete could be effectively stopped.

[Preparation of aqueous alkali metal silicate solution]
0.15 parts by weight of fumaric acid was charged into a container containing 15 parts by weight of water having a water temperature of 60 ° C., and dissolved by stirring. Subsequently, 25 parts by weight of water glass “JIS No. 3 sodium silicate” manufactured by Tosoh Sangyo Co., Ltd. was added while stirring was continued. At this time, the viscosity temporarily increased greatly in the portion where water glass was added, but the whole was homogenized by stirring. This operation was repeated to add the whole amount of water glass to prepare an aqueous solution having no uniform insoluble matter as a whole. The water glass used here contains 9 to 10% by weight of a sodium oxide (Na ₂ O: MW = 61.98) component and 28 to 30% by weight of a silicon dioxide (SiO ₂ : MW = 60.09) component. is there. When the median is adopted and the sodium oxide component is 9.5% by weight and the silicon dioxide component is 29% by weight, the ratio [metal / silicon] is 0.64. The ratio [metal / carboxyl group] of the number of sodium atoms to the number of carboxyl groups in fumaric acid (C ₄ H ₄ O ₄ : MW = 116.07) which is a divalent acid was 30. The specific gravity of the aqueous solution was 1.24.

[Drilling]
The injection hole 12 having a diameter of about 12.5 mm and a depth of about 250 mm is drilled so as to penetrate the crack 11 at an angle of 45 degrees from a position about 100 mm away from the crack 11 observed from the surface of the concrete 10, and air blow Then, the cutting powder was removed.

[Installation of injection plug]
The injection plug 20 shown in FIGS. 1 and 2 was installed in the injection hole 12 in the following manner. First, the anchor 31 was put into the injection hole 12 and hit with a hammer through a metal rod to fix the anchor 31 to the bottom 13 of the injection hole 12. Subsequently, the rod-shaped member 30 having the outer screw formed on the entire surface was screwed onto the inner screw of the anchor 31 and fixed. The upper end 35 of the rod-shaped member 30 is formed in the order of the injection plug 20, the packing 37 (O-ring), and the nut 36 whose sealing portion 24 is covered with the buffer material 25 (vinyl chloride tube) with respect to the fixed rod-shaped member 30. The injection plug 20 was fixed to the injection hole 12 by tightening the nut 36 from the side.

[Scratch seal]
The alkali metal silicate aqueous solution was applied to the surface of the concrete 10 near the crack 11. Subsequently, Mitsubishi Materials Corp. ultrafine cement "armor # 600": the (JIS R5201 measured specific surface area based on 12200cm ² / g) 100 parts by weight, those kneading by adding water 30 parts by weight, cracks 11 was rubbed against. The surface was shaved until the cement paste hardened, and the surface was finished to be flat.

[Injection of aqueous alkali metal silicate solution]
The alkali metal silicate aqueous solution is put into the tank 41, the pump 40 is operated, the tip of the hose 49 (joint 45 which is disconnected) is put into the tank 41, the aqueous solution is circulated, and the Air was removed. As the pump 40, a plunger pump having a maximum pressure of 3.2 MPa was used. The operation of the pump 40 is once stopped, the valve 50 at the tip of the hose 49 is closed, and the unit 44 provided with the pressure gauge 43 and the valve 42 is connected by joints 45 and 46, and the apparatus configuration shown in FIG. It was. While opening the valve 50 little by little, the pressure was gradually increased, and the pressure was increased to finally reach 3.0 MPa. During this time, it was confirmed that there were no leaks from surrounding cracks 11 and injection holes 12. After the pressure increase, the valve 42 was closed and the injection was performed while confirming the pressure drop of the pressure gauge 43. After the injection, the valve 40 was closed and the pump 40 was stopped. Subsequently, when the injection rate of the alkali metal silicate aqueous solution was too slow, the following [injection using a buffer part] operation was performed. When the injection rate of the alkali metal silicate aqueous solution was too fast or when leakage from cracks was confirmed, the following [Injection of fine particle cement dispersion] operation was performed. In addition, when it was determined that the injection rate of the alkali metal silicate aqueous solution was appropriate, the following [finishing] operation was performed.

[Injection using buffer part]
After the [injection of alkali metal silicate aqueous solution] operation, the pump 40 is stopped, the unit 44 provided with the pressure gauge 43 and the valve 42 is removed, and the buffer 47 and the valve 42 containing air are replaced. The unit 48 having the configuration shown in FIG. The buffer portion 47 here is a metal hollow pipe having a length of about 300 mm and an inner diameter of about 8 mm, and a pressure gauge 43 is provided at the upper end thereof. While opening the valve 50 little by little, the pressure was gradually increased, and the pressure was increased to finally reach 3.0 MPa. In this state, the valve 42 was closed, the operation of the pump 40 was stopped, the connection of the joint 45 was released, and the injection with the compressed air in the buffer unit 47 was continued. After the injection, the following [finishing] operation was performed.

[Injection of fine particle cement dispersion]
After the [injection of alkali metal silicate aqueous solution] operation, the pump 40 was stopped, the connection of the joint 45 was released, and the liquid in the hose 49 was returned to the tank 41. The pump 40 was connected to another tank 41 in which a fine particle cement dispersion obtained by adding 65 parts by weight of water to 100 parts by weight of an ultrafine particle cement “Arma # 600” manufactured by Mitsubishi Materials Corporation was added. Then, by the same operation as the above [Injection of alkali metal silicate aqueous solution], the fine particle cement dispersion was injected while confirming the injection state. After the injection, the valve 50 was closed and then the pump 40 was stopped, and the following [finishing] operation was performed.

[Finish]
The nut 36 was loosened to remove the injection plug 20 from the injection hole 12, and the rod-shaped member 30 was rotated and removed from the anchor 31. 100 parts by weight of Manor Co., Ltd. super hard cement “Arro Q” was filled with 25 parts by weight of water and kneaded, and the surface was sharpened and finished. Thereafter, the alkali metal silicate aqueous solution was applied to the surface of the concrete 10 near the injection hole 12.

It is the figure which showed the external appearance of an example of the injection | pouring plug used by this invention, and its fixing device. It is the cross-sectional schematic diagram which showed the state which fixed the injection | pouring plug of FIG. 1 to the injection hole. It is the schematic diagram which showed an example of the whole injection | pouring apparatus. It is the schematic diagram which showed another example of the whole injection | pouring apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Concrete 11 Crack 12 Injection hole 20 Injection plug 30 Rod-shaped member 31 Anchor 36 Nut 40 Pump 41 Tank 42, 50 Valve 43 Pressure gauge 45, 46 Joint 47 Buffer part

Claims (7)

An injection hole is drilled in the cracked concrete surface, an anchor is fixed inside the injection hole, a rod-shaped member is fixed to the fixed anchor, and the opening of the injection hole is fixed to the rod-shaped member. A method of repairing concrete in which an alkali metal silicate aqueous solution pressurized by a pump is pressed using an injection plug closely attached to a portion , wherein a pressure gauge is connected between the pump and the injection plug, After injecting the alkali metal silicate aqueous solution pressurized by the pump, the valve between the pump and the pressure gauge is closed, and from the subsequent pressure drop to cracking of the alkali metal silicate aqueous solution A method for repairing concrete characterized by judging the infiltration status . The anchor has an internal thread, and the rod-shaped member has an external thread and is screwed to the anchor, penetrates the injection plug, and tightens a nut through a packing to tighten the injection plug. The method for repairing concrete according to claim 1, wherein the concrete is in close contact with the opening. The method for repairing concrete according to claim 1 or 2, wherein the injection plug has a sealing portion covered with a buffer material, and the sealing portion is inserted into and closely attached to the opening of the injection hole. A buffer part containing air is connected between the pump and the injection plug, and after the alkali metal silicate aqueous solution is press-fitted from the pump, the connection between the pump and the buffer part is released. The method for repairing concrete according to any one of claims 1 to 3 , wherein the injection by the pressure of compressed air in the buffer portion is continued. The method for repairing concrete according to any one of claims 1 to 4 , wherein a pressure when the alkali metal silicate aqueous solution is injected is 0.5 to 10 MPa. The alkali metal silicate solution is one method of repairing concrete of claims 1-5 part of the silicates are those neutralized with an acid. The concrete repair according to any one of claims 1 to 6 , wherein, after the alkali metal silicate aqueous solution is injected, a fine cement dispersion or an aqueous solution in which a metal salt belonging to Group 2 of the periodic table is dissolved is subsequently injected. Method.

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