WO2024043169A1 - Adjuvant de ciment et composition de ciment - Google Patents

Adjuvant de ciment et composition de ciment Download PDF

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Publication number
WO2024043169A1
WO2024043169A1 PCT/JP2023/029727 JP2023029727W WO2024043169A1 WO 2024043169 A1 WO2024043169 A1 WO 2024043169A1 JP 2023029727 W JP2023029727 W JP 2023029727W WO 2024043169 A1 WO2024043169 A1 WO 2024043169A1
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WO
WIPO (PCT)
Prior art keywords
cement
cement admixture
calcium carbonate
admixture
calcium hydroxide
Prior art date
Application number
PCT/JP2023/029727
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English (en)
Japanese (ja)
Inventor
僚介 安田
和人 田原
Original Assignee
デンカ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by デンカ株式会社 filed Critical デンカ株式会社
Publication of WO2024043169A1 publication Critical patent/WO2024043169A1/fr

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    • 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
    • C04B14/26—Carbonates
    • C04B14/28—Carbonates of calcium
    • 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, 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, shrinkage compensating agents
    • C04B22/08—Acids or salts thereof
    • 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
    • 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
    • C04B28/08—Slag cements

Definitions

  • the present invention relates to cement admixtures and cement compositions used in the civil engineering field, architectural field, etc.
  • Patent Document 1 discloses that when used as an admixture for concrete, it is possible to reduce changes in fluidity over time and improve material separation resistance at low cost without significantly reviewing the mix or formulation of concrete. Fine powders for concrete compositions have been proposed.
  • the fine powder for concrete compositions described in Patent Document 1 contains more than 0.0 mass % and less than 1.0 mass % of quicklime fine powder and/or slaked lime fine powder in terms of free calcium oxide, and contains calcium carbonate fine powder. It contains 95.0% by mass or more.
  • there are no basic evaluations such as setting properties, initial strength, and drying shrinkage properties, and the practicality of this method is questionable.
  • the present invention has been made in order to solve the above problems, and provides a cement admixture that has good initial strength development and can also ensure good setting and drying shrinkage properties.
  • the purpose is to provide.
  • one particle contains calcium carbonate and calcium hydroxide, the mass ratio of these is within a predetermined range, and calcium carbonate and calcium hydroxide are contained in one particle.
  • the inventors have discovered that a cement admixture with a high total content of calcium hydroxide can solve the above problems, and have completed the present invention. That is, the present invention is as follows.
  • the cement according to [1] wherein the time required for the mixture of the cement admixture and water to reach pH 11 from 8 to 11 in a mass ratio of 1:300 is 10 to 30 seconds.
  • Admixture [3] The cement admixture according to [1] or [2], which is a carbonate of by-product slaked lime.
  • [4] The cement admixture according to any one of [1] to [3], which has a median diameter of 20 to 60 ⁇ m.
  • [5] A cement composition comprising the cement admixture according to any one of [1] to [4] and cement.
  • [6] The cement composition according to [5], wherein the cement is blast furnace cement.
  • the cement admixture according to this embodiment contains calcium carbonate and calcium hydroxide in one particle.
  • calcium carbonate and calcium hydroxide coexist in one particle, it is possible to obtain better initial strength development than when they exist separately.
  • the elution of alkali components is uneven, so it is thought that it is difficult to obtain a good initial strength development effect.
  • the mass ratio of calcium carbonate to calcium hydroxide is 30/70 to 97/3, preferably 50/50 to 90/10, and 70/30 to 85/15. It is more preferable that there be. When the mass ratio is less than 30/70 or more than 97/3, it becomes difficult to obtain good initial strength development and coagulation properties.
  • the total amount of calcium carbonate and calcium hydroxide in the cement admixture is 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. If the total amount is less than 50% by mass, it becomes difficult to obtain good initial strength development. Note that the upper limit of the total is 95% by mass.
  • the cement admixture according to the present embodiment contains calcium carbonate and calcium hydroxide in one particle, and the mixed state thereof is not particularly limited. It is preferable to have a core-shell structure in which calcium carbonate is mainly present and calcium carbonate is mainly present on the outside. Due to the core-shell structure, calcium carbonate, which is abundant on the outside, suppresses the elution of excess calcium, and then calcium hydroxide, which is abundant near the center, gradually elutes calcium, resulting in a good initial stage. It becomes easier to obtain strength development properties, and it becomes easier to ensure good setting and drying shrinkage properties.
  • the cement admixture according to the present embodiment has the following characteristics: In a mixed solution in which the cement admixture and water are mixed at a mass ratio of 1:300, the amount of water required to reach pH 11 from pH 8 to The time is preferably 10 to 30 seconds, more preferably 13 to 25 seconds.
  • the cement admixture has a core-shell structure. That is, in the above-mentioned liquid mixture, calcium carbonate, which is present in large quantities on the surface, is first dissolved. Since calcium carbonate has a lower pH than calcium hydroxide, the pH remains around 8 to 9 for a while (for example, 5 to 10 seconds) after preparing the mixed solution. Thereafter, when the calcium hydroxide on the center side is eluted, the pH starts to increase and finally reaches around 11.
  • the pH of the mixed solution containing only calcium carbonate powder remains around 8 even after 30 seconds, and the mixed solution made by mixing equal amounts of calcium hydroxide and calcium carbonate has a pH of around 8. Since strong basicity is predominant, the pH increases immediately after preparing the mixed solution and reaches around pH 11 in about 10 seconds. As described above, the fact that the cement admixture according to the present embodiment takes approximately 10 to 30 seconds to reach pH 11 from pH 8 is inferred to indicate that it has a core-shell structure. , it becomes easier to obtain good initial strength development more efficiently, and it becomes possible to ensure better setting properties and drying shrinkage properties.
  • the median diameter of the cement admixture according to this embodiment is preferably 20 to 60 ⁇ m. , more preferably 25 to 50 ⁇ m.
  • the median diameter can be determined, for example, by using a laser diffraction/scattering particle size distribution measuring device manufactured by HORIBA.
  • the above cement admixture can be produced by carbonating commercially available slaked lime that has been adjusted in particle size, but in this embodiment, we will focus on the effective use of waste and the mass ratio of calcium carbonate and calcium hydroxide. From the viewpoint of ease of adjustment, it is preferable to use carbonated by-product slaked lime, which is a carbonated product of by-product slaked lime.
  • By-product slaked lime which is the raw material for carbonated by-product slaked lime, is a by-product slaked lime that is produced in the acetylene gas manufacturing process using the calcium carbide method (there are wet and dry products depending on the acetylene gas manufacturing method), calcium Examples include slaked lime by-product of acetylene, such as slaked lime by-product contained in dust captured in the wet dust collection process of a carbide electric furnace.
  • the by-product slaked lime contains 65 to 95% calcium hydroxide (preferably 70 to 90%), and in addition, 0.1 to 10% calcium carbonate and 0.1 to 6.0% iron oxide. (preferably 0.1 to 3.0%).
  • the Blaine specific surface area of this by-product slaked lime is preferably 2,500 to 6,000 cm 2 /g, more preferably 3,000 to 5,500 cm 2 /g. When it is 2500 to 6000 cm 2 /g, desired carbonation treatment can be easily performed.
  • the median diameter of the by-product slaked lime is preferably 1 to 300 ⁇ m, more preferably 10 to 100 ⁇ m.
  • Carbonation of the by-product slaked lime can be carried out, for example, by placing the by-product slaked lime in a carbon dioxide-containing gas atmosphere at a temperature in the range of 0 to 75°C, and heating and/or humidifying as necessary.
  • the proportion of carbon dioxide in the carbon dioxide-containing gas is preferably 5% by volume or more, preferably 10 to 100% by volume, and more preferably 15 to 100% by volume.
  • Moisture water vapor
  • the relative humidity at 20° C. is preferably 80% RH or more, more preferably 90 RH% or more.
  • the carbonation rate of by-product slaked lime can be adjusted by adjusting the carbon dioxide concentration, temperature, humidity, carbonation time, etc. Therefore, the surface of the main component, calcium hydroxide, is carbonated to become calcium carbonate, and the core-shell structure described above can be efficiently formed. Moreover, the mass ratio of calcium carbonate and calcium hydroxide can also be easily adjusted.
  • the Blaine specific surface area of the carbonated by-product slaked lime produced as described above is preferably 2,500 to 6,000 cm 2 /g, more preferably 3,000 to 5,500 cm 2 /g, and 4,000 to 5,000 cm 2 /g. It is more preferable that When it is 2500 to 6000 cm 2 /g, it becomes easier to obtain good initial strength development, and it becomes easier to ensure good setting and drying shrinkage properties.
  • the cement composition according to this embodiment includes the cement admixture of this embodiment and cement.
  • the cement according to the present embodiment is not particularly limited, but includes, for example, various Portland cements such as normal, early strength, moderate heat, low heat, and white; ecocement manufactured using municipal garbage incineration ash and sewage sludge incineration ash as raw materials; Examples include mixed cements containing blast furnace slag, silica fume, limestone, fly ash, gypsum, etc. Among these, Portland cement and blast furnace cement are preferred, and blast furnace cement is more preferred as cements that can provide good initial strength development.
  • the cement composition may contain known additives that can be generally blended within a range that does not impede the effects of the present invention.
  • Additives include, but are not limited to, rust preventives, colorants, polymers, fibers, fluidizers, neutralization inhibitors, waterproofing agents, thickeners, waterproofing agents, retardants, early strength agents, and accelerators. , water reducer, high performance (AE) water reducer, foaming agent, foaming agent, AE agent, drying shrinkage reducer, rapid setting agent, swelling agent, cold resistance accelerator, efflorescence inhibitor, alkaline aggregate reaction inhibitor, Examples include black unevenness reducing agents and environmental purification admixtures. These additives can be used alone or in combination of two or more.
  • the cement admixture according to this embodiment in the cement composition is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, from the viewpoint of effectively exhibiting the function of the cement admixture. It is preferably 3 to 10% by mass, and more preferably 3 to 10% by mass.
  • the cement composition of this embodiment may be prepared by mixing the respective materials at the time of construction, or may be partially or entirely mixed in advance. Further, the method of mixing each material and water is not particularly limited, and each material may be mixed at the time of construction, or some or all of the materials may be mixed in advance. Alternatively, a portion of the material may be mixed with water and then the remaining material may be mixed.
  • any existing device can be used, such as a tilting mixer, omni mixer, Henschel mixer, V-type mixer, and Nauta mixer.
  • Carbonation was performed in a constant temperature and humidity chamber at 20° C., 60% RH, and a carbon dioxide concentration of 5% by volume.
  • the total amount of calcium oxide was 99% by mass, the density was 2.61 g/cm 3 , the Blaine specific surface area was 4520 cm 2 /g, and the median diameter was 21 ⁇ m).
  • the time required for cement admixture A to reach pH 11 from pH 8 was 15 seconds, which was within the range of 10 to 30 seconds.
  • the time required for cement admixture B to reach pH 11 from pH 8 was 7 seconds, and the pH increase was faster than that of cement admixture A.
  • Cement admixture A which contains calcium carbonate and calcium hydroxide in a predetermined ratio in each particle, has a higher initial strength at 3 days of age than other admixtures while ensuring good setting and drying shrinkage properties. The expression was good.
  • the present invention can be particularly suitably used as a cement admixture used in the civil engineering field, construction field, etc.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Civil Engineering (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

Cet adjuvant de ciment contient du carbonate de calcium et de l'hydroxyde de calcium dans chaque particule de celui-ci. Le rapport massique (carbonate de calcium/hydroxyde de calcium) du carbonate de calcium à l'hydroxyde de calcium est de 30/70 à 97/3. La quantité totale du carbonate de calcium et de l'hydroxyde de calcium dans l'adjuvant de ciment est de 50 % en masse ou plus.
PCT/JP2023/029727 2022-08-26 2023-08-17 Adjuvant de ciment et composition de ciment WO2024043169A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022-134999 2022-08-26
JP2022134999 2022-08-26

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WO2024043169A1 true WO2024043169A1 (fr) 2024-02-29

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59203121A (ja) * 1983-04-08 1984-11-17 Giken Kogyo Kk アンカ−体の施工方法
US6310129B1 (en) * 1997-10-02 2001-10-30 Rebaseproducts Inc. Processing and use of carbide lime
WO2013053064A1 (fr) * 2011-10-13 2013-04-18 Martin Marcus E Procédé et appareil pour la préparation de particules d'hydroxyde de calcium enrobées de carbonate de calcium

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59203121A (ja) * 1983-04-08 1984-11-17 Giken Kogyo Kk アンカ−体の施工方法
US6310129B1 (en) * 1997-10-02 2001-10-30 Rebaseproducts Inc. Processing and use of carbide lime
WO2013053064A1 (fr) * 2011-10-13 2013-04-18 Martin Marcus E Procédé et appareil pour la préparation de particules d'hydroxyde de calcium enrobées de carbonate de calcium

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