Filler, manufacturing method of structure, and method for improving ground or concrete

Abstract

To provide a filler that can render the filled portion and its surroundings more compact, maintaining the structure stable for a long period of time.SOLUTION: A filler according to the present invention contains cement milk or mortar, and an ion-releasing compound that can release cations or anions. The ion-releasing compound can produce a water-insoluble salt.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filler that can be used in structures. The present invention also relates to a method for manufacturing a structure using the filler and a method for improving ground or concrete. [Background technology]

[0002] The number of underground structures, such as tunnels, subways, underground shopping malls, and underground passages, is increasing with the development of underground spaces. When constructing an underground structure, if the concrete shrinks as it hardens or dries, cavities may form between the underground structure and the ground behind it. Cavities may also form between an underground structure and the ground behind it due to external stress such as an earthquake or ground subsidence caused by a decrease in groundwater.

[0003] If such cavities are left unattended for a long period of time, the ground (natural rock) may collapse or the underground structure may tilt, potentially making it impossible to ensure the safety of the interior of the underground structure.In order to equalize the earth pressure acting on the underground structure and prevent the ground from collapsing, a backfilling method is sometimes used, in which a filler material is injected into the cavity between the underground structure and the ground behind it.

[0004] Patent Document 1 listed below discloses a composite backfill injection waterstop method. The composite backfill injection waterstop method comprises the following steps: a step of forming an injection hole in a crack that has occurred in an underground concrete structure or in the vicinity thereof, injecting a first material through the injection hole, and creating an improved body made of the first material behind the concrete member; and a step of injecting a second material different from the first material through the injection hole or an injection hole separately formed in the vicinity thereof, using the improved body as a runaway prevention wall and creating a waterblocking body made of the second material near the back of the concrete member in the cracked portion.

[0005] Patent Document 2 below discloses a two-component mixed backfill material in which a main component of a hardening agent and a reactive agent react and solidify at the filling location. The backfill material contains air mortar as the main component and water glass as the reactive agent. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 04-001366 [Patent Document 2] Japanese Patent Application Publication No. 2019-044417 Summary of the Invention [Problem to be solved by the invention]

[0007] In order to reinforce an underground structure, if a conventional backfill material (filling material) is filled (injected) into the cavity between the underground structure and the ground, the strength of the underground structure can be increased to a certain extent.

[0008] However, if after reinforcing an underground structure, new cracks or tiny voids appear in the underground structure or ground around the filled area due to external stress or changes in environmental conditions, further reinforcement will be necessary.

[0009] Conventionally, there is no known method for repairing or strengthening existing underground structures and the surrounding areas of the underground structures in a self-healing manner over a long period of time.

[0010] The object of the present invention is to provide a filler that can densify the filled area and its surroundings and maintain a structure in a stable state for a long period of time. The present invention also provides a method for manufacturing a structure using the filler and a method for improving ground or concrete. [Means for solving the problem]

[0011] According to a broad aspect of the present invention, there is provided a filler comprising cement milk or mortar and an ion-releasing compound capable of releasing cations or anions, the ion-releasing compound being capable of generating a poorly water-soluble salt.

[0012] In a specific aspect of the filler according to the present invention, the ion-releasing compound is tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, calcium sulfate, calcium chloride, calcium bicarbonate, sodium carbonate, or sodium bicarbonate.

[0013] In a particular aspect of the filler according to the present invention, the ion-releasing compound is capable of generating calcium carbonate as a poorly water-soluble salt.

[0014] In a particular aspect of the filler according to the present invention, the surface of the ion-releasing compound is coated with a coating agent.

[0015] In a specific aspect of the filler according to the present invention, the material of the coating agent includes a resin.

[0016] In a specific aspect of the filler according to the present invention, the filler contains cement milk, and the cement milk is air milk.

[0017] In a specific aspect of the filler according to the present invention, the filler includes mortar, and the mortar is air mortar.

[0018] In a specific aspect of the filler according to the present invention, the filler contains a foaming agent, and the foaming agent is an alkaline foaming agent.

[0019] According to a broad aspect of the present invention, there is provided a method for manufacturing a structure, comprising a filling step of filling the above-mentioned filler into the filling target portion of an object to be filled, and a hardening step of hardening the cement milk or the mortar in the filler.

[0020] In a specific aspect of the manufacturing method of a structure according to the present invention, the object to be filled includes ground or concrete, and the portion to be filled is a cavity in the ground or concrete.

[0021] According to a broad aspect of the present invention, there is provided a method for improving ground or concrete, which uses the above-described filler material. [Effects of the Invention]

[0022] The filler according to the present invention includes cement milk or mortar and an ion-releasing compound capable of releasing cations or anions. In the filler according to the present invention, the ion-releasing compound is capable of generating a poorly water-soluble salt. Because the filler according to the present invention has the above-described configuration, it is possible to densify the filled area and its surroundings, thereby maintaining the structure in a stable state for a long period of time. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram illustrating a method for producing a structure using a filler according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be described in detail below.

[0025] (filling material) The filler according to the present invention contains cement milk or mortar and an ion-releasing compound capable of releasing cations or anions (hereinafter, sometimes referred to as "ion-releasing compound"). In the filler according to the present invention, the ion-releasing compound is capable of generating a poorly water-soluble salt. The filler according to the present invention is a filler for generating a poorly water-soluble salt.

[0026] In this specification, "cement milk" refers to a mixture of cement and water (mixing water). In this specification, "cement milk" does not include fine aggregate. In this specification, "mortar" refers to a mixture of cement, fine aggregate, and water (mixing water). In this specification, "cement" refers to a powder whose main ingredients are limestone, clay, silica stone, and iron oxide raw materials, etc., and which can harden through a chemical reaction with water.

[0027] In this specification, the term "poorly water-soluble salt" refers to a salt in which, when 1 g of the poorly water-soluble salt is placed in 100 g of water and kept at 20°C for 10 minutes, the weight of the poorly water-soluble salt that dissolves in water is 0.1 g or less.

[0028] The filler according to the present invention has the above-described configuration, and therefore can increase the strength of the filled area and its surroundings, and can maintain high strength for a long period of time. More specifically, when the filler is filled into the filling target area of ​​the filling target object, the ion-releasing compound in the filler releases ions, generating poorly water-soluble salts and forming concretions. This densifies the filled area and its surroundings, allowing the structure to be maintained in a stable state for a long period of time. The present invention contributes to the preventive maintenance of structures. In particular, the present invention contributes to the preventive maintenance of existing underground structures.

[0029] With the filler according to the present invention, after the filler is filled into the filling target portion of the object to be filled, the cement milk or mortar hardens, thereby increasing the strength of the filled area and its surroundings. Furthermore, when the filler comes into contact with moisture or the like adhering to the ground or a structure at the filled area, the ion-releasing compound in the filler releases ions, thereby generating a poorly water-soluble salt at the contact surface between the filler and the moisture or the like. That is, the filler according to the present invention can generate a layer of poorly water-soluble salt on the surface of the filler. The generated poorly water-soluble salt further increases the strength of the filled area and its surroundings. It is believed that the generation of the poorly water-soluble salt typically takes several months to several years. Furthermore, the generated poorly water-soluble salt effectively prevents further contact between the filler and moisture, thereby effectively preventing deterioration of the hardened filler and the structure. The filler may be the filler after the hardening reaction of the cement milk or mortar, or the hardened filler.

[0030] The filler of the present invention can be used whether the area to be filled is dry or wet. Furthermore, the filler of the present invention can be used even when water is leaking from the area to be filled. Therefore, the filler of the present invention can preserve structures for various purposes and can also quickly repair them.

[0031] The structure may be an underground structure. Examples of the underground structure include an underground concrete structure, an underground tunnel, an undersea tunnel, and a mountain tunnel. The filler according to the present invention is suitable for use in a cavity between an underground structure and the ground behind the underground structure. The filler according to the present invention is also suitable for use in a cavity that has occurred under the floor of a structure due to ground subsidence. Furthermore, the filler according to the present invention is suitable for use in cavities in tunnels and water supply and sewerage pipes that are no longer needed, and in lightweight embankments behind bridge abutments.

[0032] In order to effectively exhibit the effects of the present invention, it is preferable that the filler is a filler for a filling object containing ground or concrete.In order to effectively exhibit the effects of the present invention, it is preferable that the filler is used by filling a filling target portion of a filling object containing ground or concrete.

[0033] Hereinafter, the details of each component used in the filler according to the present invention will be described.

[0034] <Cement milk or mortar> The filler includes cement milk or mortar. The filler may include cement milk, may include mortar, or may include both cement milk and mortar.

[0035] When the filler contains cement milk, the injectability of the filler can be improved. When the filler contains mortar, shrinkage due to hardening of cement (autogenous shrinkage) and shrinkage due to drying after hardening (drying shrinkage) can be suppressed.

[0036] The cement contained in the cement milk and the mortar is not particularly limited, and examples of the cement contained in the cement milk and the mortar include portland cement, blast furnace cement, silica cement, and fly ash cement.

[0037] Examples of the fine aggregate in the mortar include artificial aggregate and natural aggregate. Examples of the artificial aggregate include blast furnace slag and fly ash. Examples of the natural aggregate include sand. From the viewpoint of reducing material costs, the fine aggregate in the mortar is preferably sand.

[0038] The average particle size of the fine aggregate in the mortar is preferably 5 μm or more, more preferably 10 μm or more, and preferably 2000 μm or less, more preferably 100 μm or less. When the average particle size of the fine aggregate in the mortar is equal to or greater than the lower limit, the strength of the mortar can be improved. When the average particle size of the fine aggregate in the mortar is equal to or less than the upper limit, the settlement of the fine aggregate in the mortar can be suppressed, and the injectability of the filler can be improved.

[0039] From the viewpoint of exerting the effects of the present invention more effectively, the cement content in 100% by weight of the cement milk is preferably 10% by weight or more, more preferably 20% by weight or more, even more preferably 30% by weight or more, and preferably 90% by weight or less, more preferably 80% by weight or less, even more preferably 70% by weight or less.

[0040] From the viewpoint of exerting the effects of the present invention more effectively, the content of water (mixing water) in the above cement milk per 100 parts by weight of cement is preferably 11 parts by weight or more, more preferably 25 parts by weight or more, even more preferably 35 parts by weight or more, and preferably 125 parts by weight or less, more preferably 100 parts by weight or less, even more preferably 67 parts by weight or less.

[0041] From the viewpoint of exerting the effects of the present invention more effectively, the cement content in 100% by weight of the mortar is preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more, and is preferably 60% by weight or less, more preferably 50% by weight or less, even more preferably 40% by weight or less.

[0042] From the viewpoint of exerting the effects of the present invention more effectively, the content of fine aggregate in 100% by weight of the mortar is preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more, and is preferably 90% by weight or less, more preferably 85% by weight or less, even more preferably 80% by weight or less.

[0043] From the viewpoint of exerting the effects of the present invention more effectively, the content of fine aggregate in the above mortar is preferably 11 parts by weight or more, more preferably 25 parts by weight or more, even more preferably 40 parts by weight or more, per 100 parts by weight of cement, and is preferably 900 parts by weight or less, more preferably 400 parts by weight or less, even more preferably 250 parts by weight or less.

[0044] From the viewpoint of exerting the effects of the present invention more effectively, the content of water (mixing water) in the above mortar is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, even more preferably 40 parts by weight or more, and is preferably 200 parts by weight or less, more preferably 100 parts by weight or less, even more preferably 60 parts by weight or less, per 100 parts by weight of cement.

[0045] From the viewpoint of exerting the effects of the present invention more effectively, the content of the cement milk or the mortar in 100% by weight of the filler is preferably 80% by weight or more, more preferably 90% by weight or more, even more preferably 95% by weight or more, and preferably 99.9% by weight or less, more preferably 99.5% by weight or less, even more preferably 99% by weight or less.

[0046] <Ion-releasing compounds> The filler contains an ion-releasing compound capable of releasing cations or anions (ion-releasing compound), which is capable of generating a poorly water-soluble salt.

[0047] The ion-releasing compound may be a compound capable of releasing cations, a compound capable of releasing anions, a compound capable of releasing both cations and anions, or a mixture of a compound capable of releasing cations and a compound capable of releasing anions. The ion-releasing compound may be in particulate form. The ion-releasing compound may be used alone or in combination of two or more types.

[0048] The ion-releasing compound preferably generates a poorly water-soluble salt upon contact with moisture or the like attached to the ground or structure. Preferably, the ion-releasing compound releases cations or anions due to water or moisture reaching the area where the filler is filled. Specifically, when the ion-releasing compound is a compound capable of releasing cations, the cations released from the ion-releasing compound preferably react with anions dissolved in moisture or the like to form a poorly water-soluble salt. When the ion-releasing compound is a compound capable of releasing anions, the anions released from the ion-releasing compound preferably react with cations dissolved in moisture or the like to form a poorly water-soluble salt. Furthermore, when the ion-releasing compound is a compound capable of releasing both cations and anions, or a mixture of a compound capable of releasing cations and a compound capable of releasing anions, the cations and anions released from the ion-releasing compound preferably migrate to a medium such as moisture and form a poorly water-soluble salt at the point where they meet.

[0049] Examples of the ion-releasing compound include tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, calcium sulfate, calcium chloride, calcium bicarbonate, sodium carbonate, and sodium bicarbonate. The ion-releasing compound is preferably tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, calcium sulfate, calcium chloride, calcium bicarbonate, sodium carbonate, or sodium bicarbonate. These ion-releasing compounds can more effectively produce poorly water-soluble salts.

[0050] Examples of the compound capable of releasing cations include tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium chloride, calcium sulfate, calcium nitrate, calcium acetate, calcium lactate, calcium bicarbonate, etc. The compound capable of releasing cations may be used alone or in combination of two or more.

[0051] From the viewpoint of more effectively exerting the effects of the present invention, the compound capable of releasing cations is preferably tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium chloride, calcium nitrate, calcium acetate, calcium lactate, or calcium bicarbonate. From the viewpoint of more effectively exerting the effects of the present invention, the compound capable of releasing cations is more preferably calcium oxide, calcium chloride, calcium nitrate, calcium acetate, or calcium lactate, and even more preferably calcium lactate. From the viewpoint of more effectively exerting the effects of the present invention, the compound capable of releasing cations is preferably a compound capable of releasing calcium ions, and more preferably an organic acid calcium salt. Examples of the organic acid calcium salt include calcium acetate and calcium lactate.

[0052] Examples of the compound capable of releasing anions include calcium bicarbonate, ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, barium carbonate, sodium carbonate, sodium bicarbonate, etc. The compound capable of releasing anions may be used alone or in combination of two or more.

[0053] From the viewpoint of more effectively exerting the effects of the present invention, the compound capable of releasing anions is preferably ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, barium carbonate, or sodium bicarbonate, and more preferably sodium bicarbonate. From the viewpoint of more effectively exerting the effects of the present invention, the compound capable of releasing anions is preferably a compound capable of releasing bicarbonate ions or carbonate ions.

[0054] Examples of the compound capable of releasing both cations and anions include calcium bicarbonate.

[0055] From the viewpoint of producing a poorly water-soluble salt more efficiently, the filler is preferably a mixture of a compound capable of releasing a cation and a compound capable of releasing an anion, and more preferably a mixture of a compound capable of releasing a calcium ion and a compound capable of releasing a bicarbonate ion or a carbonate ion.

[0056] Examples of the poorly water-soluble salt include calcium carbonate, barium carbonate, calcium phosphate, calcium sulfate, calcium silicate, and iron hydroxide.

[0057] From the viewpoint of more effectively exhibiting the effects of the present invention, the poorly water-soluble salt is preferably calcium carbonate, and from the viewpoint of more effectively exhibiting the effects of the present invention, the ion-releasing compound is preferably capable of producing calcium carbonate as the poorly water-soluble salt.

[0058] The ion-releasing compound may be spherical, may have a shape other than spherical, or may be flat, but is preferably spherical.

[0059] The particle diameter of the ion-releasing compound is preferably 1.0 μm or more, more preferably 5.0 μm or more, even more preferably 10 μm or more, and preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 120 μm or less. When the particle diameter of the ion-releasing compound is equal to or greater than the above-mentioned lower limit, the dispersibility in the filler and in the cured product of the filler can be improved. Furthermore, when the particle diameter of the ion-releasing compound is equal to or greater than the above-mentioned lower limit, the ion-releasing compound is well coated with the coating agent described below, and the dispersibility in the filler and in the cured product of the filler can be improved. When the particle diameter of the ion-releasing compound is equal to or less than the above-mentioned upper limit, the viscosity when the filler is filled into the filling target portion can be improved, and the injectability of the filler can be improved.

[0060] The particle size of the ion-releasing compound is preferably an average particle size. The average particle size indicates a number-average particle size. The average particle size of the ion-releasing compound is determined by observing 50 random ion-releasing compounds with an electron microscope or an optical microscope and calculating the average value.

[0061] In the filler, the surface of the ion-releasing compound may be coated with a coating agent. The ion-releasing compound may be encapsulated in a microcapsule. The filler may contain a microcapsule containing the ion-releasing compound as an encapsulation. When the surface of the ion-releasing compound is coated with a coating agent or the ion-releasing compound is encapsulated in a microcapsule, the timing and amount of release of cations or anions from the ion-releasing compound can be controlled.

[0062] The ion-releasing compound coated with the coating agent is preferably capable of releasing cations or anions when moisture such as water or humidity comes into contact with the filler or a cured product of the filler and the moisture diffuses and penetrates into the coating agent. The ion-releasing compound coated with the coating agent may be capable of releasing cations or anions from voids in the coating agent. The ion-releasing compound coated with the coating agent may be capable of diffusing into the coating agent and releasing cations or anions. In these cases, the timing and amount of cations or anions released from the ion-releasing compound can be more effectively controlled.

[0063] The microcapsules are preferably capable of releasing the ion-releasing compound. The membranes constituting the microcapsules preferably disintegrate upon contact with water or moisture, allowing for better control of the timing and amount of release of cations or anions from the ion-releasing compound.

[0064] The material of the membrane constituting the microcapsules and the material of the coating agent for coating the surface of the ion-releasing compound can be appropriately selected depending on the type of the ion-releasing compound. The material of the membrane constituting the microcapsules and the material of the coating agent for coating the surface of the ion-releasing compound preferably contain a resin. In this case, the dispersibility of the ion-releasing compound in the filler and in the cured product of the filler can be improved, and the timing and amount of release of cations or anions can be well controlled. Furthermore, the thickness of the membrane constituting the microcapsules can be made uniform, and the surface of the ion-releasing compound can be uniformly coated with the coating agent.

[0065] Examples of the resin include a water-soluble resin, a thermoplastic resin, a thermosetting resin, a photocurable resin, and a moisture-curable resin. The resins may be used alone or in combination of two or more.

[0066] Examples of the water-soluble resin include polyvinyl alcohol, polylactic acid resin (PLA resin), poly(meth)acrylic acid, poly(meth)acrylamide, polyvinylpyrrolidone, polyethylene oxide, and methylcellulose.

[0067] Examples of the thermoplastic resin include polyolefin resin, polyvinyl chloride resin, polyamide resin, polycarbonate resin, polystyrene resin, polyester resin, acrylonitrile-butadiene-styrene resin (ABS resin), polyethylene terephthalate (PET), and polymethyl methacrylate (PMMA).

[0068] Examples of the polyolefin resin include polyethylene, polypropylene, polystyrene, polybutene, polyisobutylene, polybutadiene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer.

[0069] Examples of the thermosetting resin include epoxy resin, phenol resin, (meth)acrylic resin, unsaturated polyester resin, vinyl ester resin, polyimide resin, urethane resin, polyurea resin, etc. The thermosetting resin may be used in combination with a thermosetting agent.

[0070] Examples of the photocurable resin include (meth)acrylic resin, (meth)acrylic urethane resin, epoxy resin, silicone resin, etc. The photocurable resin may be used in combination with a photopolymerization initiator.

[0071] Examples of the moisture-curable resin include moisture-curable urethane resins and hydrolyzable silyl group-containing resins.

[0072] From the viewpoint of better controlling the timing and amount of release of cations or anions from the ion-releasing compound, the resin preferably contains a thermoplastic resin, more preferably contains a polyolefin resin, even more preferably contains an ethylene-vinyl acetate copolymer, and is particularly preferably an ethylene-vinyl acetate copolymer.

[0073] The thickness of the membrane constituting the microcapsules and the thickness of the coating layer of the coating agent are not particularly limited. From the viewpoint of better controlling the timing and amount of release of cations or anions from the ion-releasing compound, the thickness of the membrane constituting the microcapsules and the thickness of the coating layer of the coating agent are preferably 1 μm or more, more preferably 5 μm or more, and preferably 1000 μm or less, more preferably 200 μm or less.

[0074] The content of the ion-releasing compound in 100% by weight of the filler is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and preferably 10% by weight or less, more preferably 5% by weight or less. When the content of the ion-releasing compound is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the filled area and its surroundings are further densified, and the structure can be maintained in a stable state for a longer period of time. When the content of the ion-releasing compound is below the upper limit, the viscosity of the filler when filling the filling target area can be improved, and the injectability of the filler can be improved.

[0075] The content of the ion-releasing compound is preferably 0.1 parts by weight or more, more preferably 0.3 parts by weight or more, and preferably 20 parts by weight or less, more preferably 5 parts by weight or less, and even more preferably 1 part by weight or less, per 100 parts by weight of the cement milk or the mortar. When the content of the ion-releasing compound is above the lower limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the filled area and its surroundings are further densified, and the structure can be maintained in a stable state for a longer period of time. When the content of the ion-releasing compound is below the upper limit, the viscosity of the filler when filling the target area can be improved, and the injectability of the filler can be improved.

[0076] The content of the ion-releasing compound is preferably 0.2 parts by weight or more, more preferably 0.5 parts by weight or more, and preferably 40 parts by weight or less, more preferably 10 parts by weight or less, relative to 100 parts by weight of the cement content in the cement milk or mortar. When the content of the ion-releasing compound is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced efficiently. As a result, the filled area and its surroundings are further densified, and the structure can be maintained in a stable state for a longer period of time. When the content of the ion-releasing compound is below the upper limit, the viscosity of the filler when filling the target area can be improved, thereby improving the injectability of the filler.

[0077] The total content of the ion-releasing compound and the coating agent in 100% by weight of the filler is preferably 0.5% by weight or more, more preferably 1.5% by weight or more, and preferably 50% by weight or less, more preferably 25% by weight or less. When the total content of the ion-releasing compound and the coating agent is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced efficiently. As a result, the filled area and its surroundings are further densified, and the structure can be maintained in a stable state for a longer period of time. When the total content of the ion-releasing compound and the coating agent is below the upper limit, the viscosity of the filler when filled into the filling target area can be improved, thereby improving the injectability of the filler.

[0078] <Foaming agent> From the viewpoint of increasing the lightness and fluidity of the filler, it is preferable that the cement milk or the mortar is used by mixing air bubbles. From the viewpoint of increasing the lightness and fluidity of the filler, it is preferable that the filler contains cement milk, and the cement milk is aerated milk. From the viewpoint of increasing the lightness and fluidity of the filler, it is preferable that the filler contains mortar, and the mortar is aerated mortar. From the viewpoint of increasing the lightness and fluidity of the filler, it is preferable that the filler contains aerated milk or aerated mortar. Aerated milk is a mixture of the cement milk and air bubbles, and aerated mortar is a mixture of the mortar and air bubbles.

[0079] From the viewpoint of stabilizing and favorably dispersing the air bubbles (air) in the aerated milk or aerated mortar, the filler preferably contains a foaming agent.

[0080] The foaming agent includes animal protein surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

[0081] Examples of the anionic surfactant include alkyl sulfates (AS), alkyl ether sulfates (AES), alkyl benzene sulfonates (LAS), and sodium alpha olefin sulfonates (AOS).

[0082] From the viewpoint of more effectively forming a poorly water-soluble salt and preventing the generated poorly water-soluble salt from redissolving, the foaming agent is preferably an alkaline foaming agent, preferably an anionic surfactant, and more preferably an alkaline anionic surfactant. From the viewpoint of more effectively forming a poorly water-soluble salt and preventing the generated poorly water-soluble salt from redissolving, the pH of the foaming agent is preferably 7 or more, more preferably 8 or more, and preferably 12 or less, more preferably 11 or less. If the foaming agent is an acidic foaming agent, the generated poorly water-soluble salt may redissolve. In particular, when the ion-releasing compound is a compound capable of releasing carbonate ions, if the foaming agent is acidic, the proportion of carbonate ions present may decrease, making it difficult to form the poorly water-soluble salt.

[0083] As a method for mixing air bubbles into the cement milk or the mortar using the foaming agent (a method for producing air milk or air mortar), a conventionally known method can be used. As a method for mixing air bubbles into the cement milk or the mortar using the foaming agent, a pre-forming method, a mixed foaming method, or the like can be used.

[0084] From the viewpoint of further increasing the lightness of the filler, the air content (volume content) of the filler containing the air milk or air mortar is preferably 20% or more, more preferably 30% or more, and is preferably 80% or less, more preferably 70% or less.

[0085] The amount of air can be measured by the alcohol method, the specific gravity measurement method, or the like.

[0086] The content of the foaming agent in 100% by weight of the filler is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and preferably 5% by weight or less, more preferably 3% by weight or less. When the content of the foaming agent is above the lower limit and below the upper limit, the air bubbles in the aerated milk or aerated mortar can be further stabilized and dispersed more effectively.

[0087] The content of the foaming agent is preferably 0.2 parts by weight or more, more preferably 0.4 parts by weight or more, and preferably 10 parts by weight or less, more preferably 6 parts by weight or less, relative to 100 parts by weight of the cement milk. When the content of the foaming agent is equal to or more than the lower limit and equal to or less than the upper limit, the air bubbles in the aerated milk can be further stabilized and dispersed more effectively.

[0088] The content of the foaming agent is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, and preferably 5 parts by weight or less, more preferably 3 parts by weight or less, relative to 100 parts by weight of the mortar. When the content of the foaming agent is equal to or more than the lower limit and equal to or less than the upper limit, the air bubbles (air) in the air mortar can be further stabilized and dispersed more effectively.

[0089] The content of the foaming agent is preferably 0.1 part by weight or more, more preferably 0.3 part by weight or more, and preferably 10 parts by weight or less, more preferably 6 parts by weight or less, relative to 100 parts by weight of the cement content in the cement milk or mortar. When the content of the foaming agent is equal to or more than the lower limit and equal to or less than the upper limit, the air bubbles (air) in the aerated milk or aerated mortar can be further stabilized and dispersed more effectively.

[0090] The foaming agent is preferably diluted with water (dilution water) before use. The filler preferably contains the foaming agent and water (dilution water). Examples of the dilution water include seawater, river water, lake water, tap water, industrial water, and deionized water.

[0091] From the viewpoint of further increasing the lightness of the filler, the dilution ratio of the foaming agent is preferably 5 times or more, more preferably 10 times or more, and is preferably 50 times or less, more preferably 30 times or less.

[0092] When the filler contains a foaming agent and dilution water, the ratio W / C (%) of the content (weight) of water (W) in the filler material (specifically, for example, the total content (weight) of mixing water, foaming agent, and dilution water) to the content (weight) of cement (C) is defined as the water-cement ratio. From the viewpoint of further increasing the lightness of the filler, the water-cement ratio is preferably 70% or more, more preferably 80% or more, and preferably 150% or less, more preferably 140% or less.

[0093] <Other ingredients> The filler may contain other components, as necessary, in addition to the cement milk, mortar, ion-releasing compound, and foaming agent, such as a reaction catalyst, a reaction accelerator, a crosslinking agent, a water absorbent, a foam stabilizer, an antioxidant, and a colorant.

[0094] (Other details of filling material) The filler is preferably a filler used by mixing. The filler is preferably a filler used by mixing the cement milk or the mortar with the ion-releasing compound. The filler is more preferably a filler used by mixing the aerated milk or the aerated mortar with the ion-releasing compound.

[0095] (Method for improving ground or concrete, structure, and method for manufacturing structure) The filler according to the present invention can be used to improve ground or concrete. The method for improving ground or concrete according to the present invention is a method for improving ground or concrete using the above-mentioned filler. To improve the ground or concrete, the filler is injected into the ground or concrete.

[0096] Furthermore, a structure can be obtained using the filler according to the present invention. The structure preferably comprises a filling target having a filling target portion, and a filler filled in the filling target portion. The filler is preferably formed from the filler. The filler is a filler formed by hardening the cement milk or the mortar in the filler. The filler is a hardened product of the filler.

[0097] The method for manufacturing a structure according to the present invention includes a filling step of filling the filling target portion of an object to be filled with the above-mentioned filler, and a hardening step of hardening the cement milk or the mortar in the filler.

[0098] The method for manufacturing a structure provides a structure having a filler filled in the filling target portion. The filler is a filler obtained by curing the curable component in the filler. The filler is a cured product of the filler.

[0099] In the structure, the area filled with the filler and its surroundings are densified by the filler, so that the structure can be maintained in a stable state for a long period of time.

[0100] In order to effectively achieve the effects of the present invention, it is preferable that the object to be filled includes ground or concrete. In order to effectively achieve the effects of the present invention, it is preferable that the object to be filled is a cavity in the ground or concrete.

[0101] The method for manufacturing the structure preferably comprises the following steps: (1) a step of mixing the cement milk or the mortar with the ion-releasing compound to obtain a filler. (2) a filling step of filling the part to be filled with the filler. (3) a hardening step of hardening the cement milk or the mortar in the filler. The method for manufacturing the structure more preferably comprises the following steps: (1A) a step of mixing the cement milk or the mortar with the foaming agent and dilution water to obtain aerated milk or aerated mortar. (1B) a step of mixing the aerated milk or the aerated mortar with the ion-releasing compound to obtain a filler. (2) a filling step of filling the part to be filled with the filler. (3X) a hardening step of hardening the aerated milk or the aerated mortar in the filler.

[0102] The method for mixing the cement milk or the mortar (the aerated milk or the aerated mortar) with the ion-releasing compound is not particularly limited. The cement milk or the mortar (the aerated milk or the aerated mortar) and the ion-releasing compound are preferably mixed when the filler is filled (injected). A mixing unit, an extruder, or a blender may be used for mixing.

[0103] The filler is used by filling the part to be filled. There are no particular limitations on the method for filling the part to be filled with the filler. Examples of methods for filling the part to be filled with the filler include forming an injection port in the structure that penetrates from the front to the back of the structure, and injecting the filler into the part to be filled through the injection port. The amount of the filler injected can be changed as appropriate depending on the size of the area to be filled (the part to be filled). The part to be filled is preferably a cavity. The part to be filled may be a cavity between an underground structure and the ground. The filler is preferably filled by a backfilling method.

[0104] The pressure when filling (injecting) the filler can be changed as appropriate depending on the viscosity of the filler, the size of the part to be filled (the part to be filled), etc. The filler may be filled (injected) at high pressure or low pressure. When filling at high pressure, the pressure is preferably 0.5 MPa or more and 24 MPa or less. When filling at low pressure, the pressure is preferably 0.01 MPa or more and 0.5 MPa or less. From the viewpoint of improving the injectability of the filler into the fine parts of the part to be filled, the pressure when injecting the filler is preferably 0.1 MPa or more and 4 MPa or less.

[0105] FIG. 1 is a schematic diagram illustrating a method for producing a structure using a filler according to one embodiment of the present invention.

[0106] The structure 100 is an underground structure. Between the structure 100 and the ground 102, a portion to be filled (void) 103 is generated.

[0107] The filler supply device 5 includes an injection gun 51 and a tank 52. The tank 52 is filled with the filler.

[0108] First, a hole is drilled at a predetermined angle from the front to the back of the structure 100 to form the injection port 101. Next, the injection plug 1 is connected to the injection gun 51. After that, a compressor is used to fill (inject) the filler material into the filling target portion 103 through the injection port 101 (filling step). Prior to the filling step, an injection plate may be installed on the front side of the structure so as to cover the periphery of the injection plug, in order to prevent the filler material from leaking out of the front of the structure.

[0109] Next, the cement milk or the mortar in the filler is hardened (hardening step). In this way, a structure can be obtained. The structure includes a hardened product of the filler as a filler filled in the filling target portion. The hardened product of the filler is formed in the structure.

[0110] The hardened filler preferably contains the hardened cement milk or mortar and the ion-releasing compound. The ion-releasing compound in the hardened filler is a compound capable of releasing cations or anions. The ion-releasing compound in the hardened filler is capable of generating a poorly water-soluble salt inside or on the surface of the hardened filler. The ion-releasing compound in the hardened filler is preferably dispersed in the hardened cement milk or mortar.

[0111] The compressive strength of the cured product of the filler in the structure is preferably 0.1 N / mm 2 More preferably, 0.3N / mm 2 or more, preferably 30N / mm 2 Less than or equal to 16N / mm 2 When the compressive strength of the cured product of the filler in the structure is equal to or greater than the lower limit, the strength of the cured product of the filler can be increased, and the durability of the resulting structure can be improved. When the compressive strength of the cured product of the filler in the structure is equal to or less than the upper limit, the distribution of stress generated in and around the filled area can be improved when the structure is subjected to external stress such as an earthquake.

[0112] The compressive strength of the cured filler in the structure can be measured by the following method. The filler is poured into a triple mold (4 cm wide x 4 cm high x 16 cm long) and cured at 17°C to 23°C and 90% RH to prepare a test specimen. The compressive strength of the obtained test specimen is measured in accordance with JIS R5201.

[0113] In the structure, the area filled with the filler and its surroundings can be densified, and the structure can be maintained in a stable state for a long period of time.

[0114] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0115] The following materials were prepared:

[0116] (cement milk or mortar) Cement (Taiheiyo Cement Corporation's "Blast Furnace Type B Cement") Fine aggregate (sand, average particle size 50μm) Mixing water

[0117] (Foaming agent and dilution water) Alkaline anionic surfactant ("Air Ball Q" manufactured by Tachibana Materials Co., Ltd.) Neutral anionic surfactant (Sanko Colloid Chemical Co., Ltd. "Sanko Neosol") Dilution water

[0118] (ion-releasing compounds) Sodium bicarbonate (Fujifilm Wako Pure Chemical Industries, Ltd., average particle size 107 μm) Calcium lactate (Nacalai Tesque, average particle size 50 μm)

[0119] (coating agent) Ethylene-vinyl acetate copolymer (Tosoh Corporation's "EVA Ultrathene #636")

[0120] Example 1 Making air-dried milk: Cement milk was obtained by mixing 30 kg of cement with 20 kg of mixing water. Next, 2.584 kg of dilution water was added to 0.136 kg of alkaline anionic surfactant to dilute the mixture 20 times, and after mixing with air bubbles, the mixture was mixed with the cement milk to obtain air milk (preform method).

[0121] Preparation of the filling material: Sodium bicarbonate and ethylene-vinyl acetate copolymer were melt-mixed in an extruder, extruded into strands, pelletized, freeze-pulverized, and classified to obtain a powder with an average particle size of 50 μm, in which at least a portion of the surface of sodium bicarbonate (ion-releasing compound) was coated with ethylene-vinyl acetate copolymer (coating agent). The content of ethylene-vinyl acetate copolymer in 100% by weight of the powder was 80% by weight. 0.3 kg of the resulting powder was mixed with air-dried milk to obtain a filler.

[0122] Preparation of hardened filler: The resulting filler was filled into a cylindrical container having a diameter of 100 mm, and after leaving it to harden for one month, it was removed from the container to obtain a hardened filler.

[0123] Examples 2 to 4 Fillers and cured products of the fillers were obtained in the same manner as in Example 1, except that the composition and content of the filler were changed as shown in Table 1 below.

[0124] (Comparative Example 1) A filler and a cured product of the filler were obtained in the same manner as in Example 1, except that the ion-releasing compound and the coating agent were not used.

[0125] (Comparative Example 2) A filler and a cured product of the filler were obtained in the same manner as in Example 2, except that the ion-releasing compound and the coating agent were not used.

[0126] (evaluation) (1) Water-cement ratio For each filler material, the ratio W / C (%) of the water (W) content (weight) (the total content (weight) of mixing water, foaming agent, and dilution water) to the cement (C) content (weight) was calculated and used as the water-cement ratio.

[0127] (2) Air volume The air content of the resulting filler was calculated by specific gravity measurement.

[0128] (3) Compressive strength The compressive strength of the resulting cured filler was measured by the method described above.

[0129] (4) Formation of poorly water-soluble salts The hardened fillers obtained in Examples 1, 2, and 4 and Comparative Examples 1 and 2 were immersed in a 1000 ppm calcium chloride solution for one month. The hardened filler obtained in Example 3 was also immersed in ion-exchanged water for one month. After immersion, the hardened fillers were removed and visually inspected in detail to determine whether particles had precipitated on the surface of the hardened fillers. When particles had precipitated on the surface, they were observed using a scanning electron microscope, revealing aggregates of particles with a dense crystalline structure (calcium carbonate calcite structure). The generation of poorly water-soluble salts (calcium carbonate) was evaluated according to the following criteria:

[0130] [Criteria for determining the formation of poorly water-soluble salts] ○○: The surface area where particles are deposited is 20% or more out of the total surface area of ​​the hardened filler material (100%). ○: The surface area where particles are precipitated is more than 0% and less than 20% of the total surface area of ​​the hardened filler (100%). ×: No particles precipitate on the surface of the cured filler

[0131] The composition of the filler and the results are shown in Tables 1 and 2 below.

[0132] [Table 1]

[0133] [Table 2] [Explanation of symbols]

[0134] 1...Injection plug 5...Feeding device 51...Injection gun 52...Tank 100...Structure 101…Inlet 102...ground 103...Filling target portion (cavity)

Claims

1. A method for manufacturing a foaming agent, comprising: a cement milk or mortar; an ion-releasing compound capable of releasing cations or anions; and a foaming agent; the ion-releasing compound is capable of forming a poorly water-soluble salt, the ion-releasing compound is calcium bicarbonate, sodium carbonate, or sodium bicarbonate; the surface of the ion-releasing compound is coated with a coating agent; A filler, wherein the foaming agent has a pH of 7 or higher.

2. The filler according to claim 1 , wherein the ion-releasing compound is capable of producing calcium carbonate as a poorly water-soluble salt.

3. The filler according to claim 1 or 2, wherein the material of the coating agent comprises a resin.

4. Contains cement milk, The filler according to any one of claims 1 to 3, wherein the cement milk is air milk.

5. Including mortar, The filler according to any one of claims 1 to 3, wherein the mortar is air mortar.

6. A filler described in any one of claims 1 to 5, wherein the foaming agent is an alkaline foaming agent.

7. a filling step of filling a filling target portion of an object to be filled with the filler according to any one of claims 1 to 6; and a hardening step of hardening the cement milk or the mortar in the filler.

8. The filling object includes ground or concrete, The method for manufacturing a structure according to claim 7 , wherein the portion to be filled is a cavity in the ground or the concrete.

9. A method for improving ground or concrete, comprising improving the ground or concrete using the filler according to any one of claims 1 to 6.

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