Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B1/00—Producing shaped prefabricated articles from the material
  • B28B1/30—Producing shaped prefabricated articles from the material by applying the material on to a core or other moulding surface to form a layer thereon
  • B28B1/32—Producing shaped prefabricated articles from the material by applying the material on to a core or other moulding surface to form a layer thereon by projecting, e.g. spraying
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B14/02—Granular materials, e.g. microballoons
  • C04B14/04—Silica-rich materials; Silicates
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators or shrinkage compensating agents
  • C04B22/06—Oxides, Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators or shrinkage compensating agents
  • C04B22/08—Acids or salts thereof
  • C04B22/14—Acids or salts thereof containing sulfur in the anion, e.g. sulfides
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates

Definitions

• the present invention relates to a liquid quick-setting agent and sprayed concrete.
• a method of spraying quick-setting concrete in which a quick-setting agent is mixed into the concrete, has been used to prevent the collapse of exposed ground during tunnel excavation, etc.
• This method involves measuring and mixing the materials at a measuring plant installed at the excavation site to prepare the sprayed concrete, which is then pumped and mixed with quick-setting agent pumped in from the other side of the junction pipe, and sprayed onto the ground surface until a specified thickness is reached.
• the quick-setting agents used in the spraying method can be broadly classified into two types: powder quick-setting agents whose main components are calcium aluminate or alkali metal aluminate, and liquid quick-setting agents whose main components are alkali metal aluminate or aluminum sulfate.
• liquid quick-setting additives have the problem of having lower quick-setting properties compared to powder quick-setting additives. Therefore, measures to improve quick-setting properties have been taken, such as those shown in Patent Document 1, in which the concentration of sulfate ions is increased.
• Patent Document 2 proposes liquid quick-setting agents consisting of aluminum fluoride, an acidic or basic solution of aluminum containing aluminum hydrofluoric acid as a component, lithium silicate, and lithium aluminate.
• Patent Document 3 proposes liquid quick-setting agents consisting of fluoride-containing water-soluble aluminum salts obtained by the reaction of aluminum sulfate with hydrofluoric acid, aluminum hydroxide, and lithium hydroxide, lithium carbonate, lithium sulfate, etc.
• the present invention aims to provide a liquid quick-setting agent that has excellent quick-setting properties, strength development, and finish properties.
• the present invention is as follows.
• a liquid quick-setting admixture containing, in terms of oxide, 2.5 to 21.0 mass%, 7.5 to 30.0 mass%, and 50 to 15,000 mass ppm of aluminum, sulfur, and silicon, respectively.
• the liquid quick-setting admixture according to the above [1] further containing 1 to 4,000 ppm by mass of calcium in terms of oxide.
• the liquid quick-setting admixture according to the above [1] or [2] which has a peak in the chemical shift range of 0 ppm to 2.0 ppm in a spectrum obtained by 27 Al-NMR measured under the following conditions.
• the present invention makes it possible to provide a liquid quick-setting agent that has excellent quick-setting properties, strength development, and finish properties.
• the liquid quick-setting admixture according to this embodiment is a liquid quick-setting admixture containing, in terms of oxide, 2.5 to 21.0 mass %, 7.5 to 30.0 mass %, and 50 to 15,000 mass ppm of aluminum, sulfur, and silicon, respectively.
• the liquid quick-setting admixture contains 2.5 to 21.0 mass% of aluminum, calculated as an oxide ( Al2O3 ), preferably 3.5 to 18.0 mass%, more preferably 4.5 to 15.0 mass%, and even more preferably 5.0 to 12.0 mass%. If the amount of aluminum in the liquid quick-setting admixture calculated as an oxide is less than 2.5 mass%, the quick-setting ability may not be exhibited, whereas if it exceeds 21.0 mass%, the strength development and finish may be poor.
• the liquid quick-setting admixture contains 7.5 to 30.0 mass% of sulfur, calculated as oxide ( SO3 ), preferably 8.5 to 28.0 mass%, more preferably 12.0 to 27.0 mass%, and even more preferably 13.5 to 20.0 mass%. If the amount of sulfur in the liquid quick-setting admixture calculated as oxide is less than 7.5 mass%, strength development may not be achieved, and if it exceeds 30.0 mass%, quick-setting properties and strength development may be poor.
• SO3 oxide
• the liquid quick-setting admixture contains 50 to 15,000 mass ppm of silicon, calculated as oxide ( SiO2 ), preferably 150 to 9,000 mass ppm, more preferably 500 to 7,000 mass ppm, and even more preferably 1,000 to 5,000 mass ppm. If the amount of silicon in the liquid quick-setting admixture calculated as oxide is less than 50 mass ppm or more than 15,000 mass ppm, the finish may be poor.
• the liquid quick-setting admixture further contains calcium, calculated as oxide (CaO), preferably in an amount of 1 to 4,000 ppm by mass, more preferably 100 to 3,800 ppm by mass, and even more preferably 750 to 3,500 ppm by mass.
• CaO calcium, calculated as oxide
• the mass ratio (Al 2 O 3 /SiO 2 ) of aluminum and silicon in the liquid quick-setting admixture calculated as oxides thereof is preferably from 3 to 1,000, more preferably from 5 to 500, and even more preferably from 10 to 150.
• Al 2 O 3 /SiO 2 is within the above range, quick-setting properties, strength development, and finish properties tend to be good.
• the liquid quick-setting admixture has a peak in the chemical shift range of 0 ppm or more and 2.0 ppm or less.
• the half-width of the peak is, for example, preferably 2.0 ppm or less, more preferably 1.8 ppm or less, and even more preferably 1.5 ppm or less. This can improve the storage stability of the quick-setting admixture.
• the half-width may be, for example, 0.1 ppm or more.
• the 27 Al-NMR measurement of the liquid quick-setting admixture can be performed using a commercially available measuring device, for example, a superconducting nuclear magnetic resonance device (ECX-400) manufactured by JEOL Ltd., under the following conditions.
• a commercially available measuring device for example, a superconducting nuclear magnetic resonance device (ECX-400) manufactured by JEOL Ltd., under the following conditions.
• Observed nucleus 27Al Sample tube rotation speed: 12Hz
• Pulse width 5 ⁇ sec (45° pulse) Waiting time: 5 seconds
• External standard Aluminum chloride aqueous solution
• the pH of the liquid quick-setting admixture is preferably 4.0 or less, and more preferably 3.5 or less. A pH of 4.0 or less reduces the environmental impact and suppresses adverse effects on the human body. The pH is preferably 1.5 or more. The pH of the liquid quick-setting admixture can be measured using a pH meter.
• the fluoride ion concentration in the liquid quick-setting admixture is preferably 1.0 to 500 ppm, more preferably 1.0 to 450 ppm, and even more preferably 1.0 to 350 ppm.
• the fluoride ion concentration is within the above range, false setting caused by rapid hydration due to the addition of the quick-setting admixture is easily mitigated, and good workability is easily achieved.
• the total alkali amount R 2 O (R is an alkali metal) in the liquid quick-setting admixture is preferably 1.0 mass% or less, more preferably 0.8 mass% or less, and even more preferably 0.5 mass% or less, from the viewpoint of worker safety. It may also be 0 mass% or more.
• the total alkali amount R 2 O in the liquid quick-setting admixture can be set within the above range.
• the total alkali amount R 2 O in the liquid quick-setting admixture can be measured by atomic absorption spectrometry.
• the chloride ion concentration in the liquid quick-setting admixture is preferably 5.0 mass% or less, more preferably 3.0 mass% or less, and even more preferably 2.0 mass% or less.
• the chloride ion concentration in the liquid quick-setting admixture can be within the above range.
• the chloride ion concentration in the liquid quick-setting admixture can be measured using a commercially available analyzer, for example, an ion chromatograph (ICS2100) manufactured by Thermo Scientific. When analyzing, the measurement can be performed by diluting the solution in advance so that the chloride ions are within the calibration curve.
• the liquid quick-setting admixture can be obtained by mixing raw materials containing aluminum such as aluminum sulfate, aluminum hydroxide, various alums, ground granulated blast furnace slag, and aluminum dross ash, raw materials containing sulfur such as sulfuric acid, and raw materials containing silicon such as fly ash, silica fume, ground granulated blast furnace slag, amorphous silica, and aluminum dross ash, and reacting them at high heat.
• Raw materials containing calcium such as calcium oxide, calcium hydroxide, ground granulated blast furnace slag, and carbide slag can also be used.
• the heating temperature is preferably 70 to 100°C, more preferably 85 to 100°C, and even more preferably 85 to 95°C.
• the reaction time is preferably 30 to 150 minutes, more preferably 60 to 150 minutes, and even more preferably 90 to 120 minutes. That is, the liquid quick-setting admixture can be prepared by mixing aluminum hydroxide, sulfuric acid, and ground granulated blast furnace slag, and heating them at 85 to 95°C for 90 to 120 minutes.
• the position and half-width of the peak in the spectrum obtained by 27Al -NMR of the liquid quick-setting admixture are influenced by the ratio of the raw materials of aluminum, sulfur, and silicon.
• the ratio of the raw material of aluminum to the raw material of sulfur if the ratio of the raw material of aluminum is increased, the chemical shift tends to fall within the desired range, whereas if the ratio of the raw material of sulfur is increased, the half-width tends to become smaller.
• liquid quick-setting admixture can contain various additives as long as they do not impair the effects of the present invention, but from the standpoint of ease of handling, it is preferable that it does not contain sodium aluminum dioxide.
• Sprayed concrete actually uses cement
• cements that can be used in sprayed concrete include various types of Portland cement, such as normal, early strength, extra early strength, low heat, and medium heat, various mixed cements that mix Portland cement with blast furnace slag, fly ash, or silica, filler cements that mix limestone powder or ground cooled blast furnace slag, and environmentally friendly cements (ecocement) made from municipal waste incineration ash and sewage sludge incineration ash.
• Portland cement such as normal, early strength, extra early strength, low heat, and medium heat
• various mixed cements that mix Portland cement with blast furnace slag, fly ash, or silica
• filler cements that mix limestone powder or ground cooled blast furnace slag
• environmentally friendly cements ecocement
• sprayed concrete uses aggregate, but there are no particular limitations on the aggregate, and it is preferable to use aggregate with low water absorption and high aggregate strength. There are no particular limitations on the maximum size of the aggregate, so long as it can be sprayed. As fine aggregate, river sand, mountain sand, sea sand, lime sand, silica sand, etc. can be used, and as coarse aggregate, river gravel, mountain gravel, lime gravel, etc. can be used, and crushed sand and crushed stone can also be used.
• the powder quick-setting admixture is preferably a powder quick-setting admixture containing calcium aluminate as a main component.
• containing calcium aluminate as a main component means that the content (by mass) of calcium aluminate is the highest among the components of the powder quick-setting admixture.
• the calcium aluminate content in the powder quick-setting admixture is 30% or more, preferably 30-80%, and more preferably 45-60%. If it is 30% or more, good setting properties are more likely to be obtained. If it is 80% or less, good long-term strength is more likely to be obtained.
• Calcium aluminate is a general term for compounds having CaO and Al 2 O 3 as main components and having hydration activity, and is a compound in which part of CaO and/or Al 2 O 3 is replaced with an alkali metal oxide, an alkaline earth metal oxide, silicon oxide, titanium oxide, iron oxide, an alkali metal halide, an alkaline earth metal halide, an alkali metal sulfate, an alkaline earth metal sulfate, or the like, or a substance in which a small amount of these are dissolved in a substance having CaO and Al 2 O 3 as main components, and calcium aluminate may be either crystalline or amorphous.
• crystalline calcium aluminate examples include C3A and its alkali metal solid solution such as C14RA5 , CA, C12A7 , C11A7.CaF2 , C4A.Fe2O3 , and C3A3.CaSO4 , where C is CaO , A is Al2O3 , and R2O ( Na2O , K2O , Li2O ) is R.
• amorphous calcium aluminate is preferred because of its good quick-setting property.
• the vitrification rate is preferably 80 % or more.
• the CaO/Al 2 O 3 molar ratio of calcium aluminate is not particularly limited, but in consideration of the very early and long-term strength development, the molar ratio is preferably 2.0 to 3.0, more preferably 2.1 to 2.8. If the molar ratio is 2.0 or more, the very early setting properties can be made good, and if it is 3.0 or less, good long-term strength development is easily obtained.
• Methods for obtaining calcium aluminate include heat treating a CaO raw material such as calcium carbonate or calcium hydroxide with an Al 2 O 3 raw material such as bauxite in a rotary kiln or electric furnace. Specifically, the raw materials are mixed in a predetermined ratio, heated and melted in an electric furnace, and quenched by contacting with compressed air or water.
• the CaO/Al 2 O 3 molar ratio can be adjusted by adjusting the ratio of the raw materials, and the vitrification rate can be adjusted by the temperature during heating and melting and the cooling method.
• the Blaine specific surface area of calcium aluminate is preferably 4,000 to 8,000 cm 2 /g, and more preferably 5,000 to 7,000 cm 2 /g. By having the specific surface area of 4,000 to 8,000 cm 2 /g, early strength development is easily achieved and the handling of mortar and/or concrete during spraying can be improved.
• the Blaine specific surface area is measured based on the specific surface area test described in JIS R 5201:2015 "Physical testing methods for cement".
• the amount of liquid quick-setting agent added to the shotcrete can be adjusted so that the aluminum component in the liquid quick-setting agent is preferably 0.1 to 20 parts by mass per 100 parts by mass of cement in the shotcrete.
• the amount of powder quick-setting agent added can be adjusted so that the calcium aluminate in the powder quick-setting agent is preferably 1 to 15 parts by mass per 100 parts by mass of cement.
• the amounts of liquid quick-setting agent and powder quick-setting agent added can be adjusted as described above according to the required strength of the shotcrete, and the initial and long-term compressive strength of the shotcrete can be improved.
• the mixing ratio of the liquid quick-setting agent and the powder quick-setting agent can be adjusted so that, for example, when the ground condition is poor, the early strength of the shotcrete can be improved by adding a larger amount of powder quick-setting agent, and when the ground condition is stable, the amounts of both quick-setting agents used can be reduced.
• Aluminum source Aluminum hydroxide, for industrial use.
• Sulfur source Sulfuric acid, for industrial use.
• Silicon source amorphous silica, industrial grade.
• Source of calcium slaked lime, for industrial use.
• Solvent pure water.
• Ordinary Portland cement commercially available product, Blaine value 3,200 cm 2 /g Fine aggregate: sand from the Himekawa River system in Itoigawa City, Niigata Prefecture, maximum dimension 5 mm or less, density 2.62 g/cm 3 .
• - Coarse aggregate No. 6 crushed stone from Itoigawa, Niigata Prefecture, maximum dimension 15 mm, density 2.67 g/cm 3 .
• Water tap water.
• Water reducing agent Commercially available product, high-performance water reducing agent.
• each specimen was polished with a specimen end surface finishing machine (manufactured by Marui Co., Ltd.), and the height of the specimen on a circumference of ⁇ 100 mm centered on the reference point was measured at 6 points x 5 points every 60 °, for a total of 30 points, and the standard deviation of the height was calculated. If the value of the standard deviation was small, it was judged that the unevenness of the finish was small and good.
• the upper surface of the specimen was polished and the compressive strength at 28 days was measured in accordance with JIS A 1107:2022 "Method of extracting cores from concrete and method of testing compressive strength" and JIS A 1132:2020 "Method of preparing specimens for strength testing of concrete”.
• the liquid quick-setting agent of the present invention can be suitably used for cement concrete that is sprayed onto exposed natural ground surfaces such as road, railway, and waterway tunnels, as well as on slopes, etc.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Inorganic Chemistry (AREA)
• Civil Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Coating By Spraying Or Casting (AREA)
• Aftertreatments Of Artificial And Natural Stones (AREA)

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Citations (8)

• 2024
  • 2024-02-06 JP JP2024576854A patent/JPWO2024166900A1/ja active Pending
  • 2024-02-06 TW TW113104732A patent/TW202438471A/zh unknown
  • 2024-02-06 WO PCT/JP2024/003848 patent/WO2024166900A1/ja not_active Ceased

Patent Citations (8)

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