WO2024043169A1 - Cement admixture and cement composition - Google Patents

Cement admixture and cement composition 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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cement
cement admixture
calcium carbonate
admixture
calcium hydroxide
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PCT/JP2023/029727
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French (fr)
Japanese (ja)
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僚介 安田
和人 田原
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デンカ株式会社
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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)
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Abstract

This cement admixture contains calcium carbonate and calcium hydroxide in each particle thereof. The mass ratio (calcium carbonate/calcium hydroxide) of the calcium carbonate to the calcium hydroxide is 30/70 to 97/3. The total amount of the calcium carbonate and the calcium hydroxide in the cement admixture is 50 mass% or more.

Description

セメント混和材及びセメント組成物Cement admixtures and cement compositions
　本発明は、土木分野、建築分野等で用いられるセメント混和剤及びセメント組成物に関する。 The present invention relates to cement admixtures and cement compositions used in the civil engineering field, architectural field, etc.
　近年、土木分野、建築分野等において、コンクリートを用いた構造物の増加若しくは大型化、老朽化した構造物の補修若しくは補強の必要性から、コンクリートの需要が増すことが予想される。
　一方で、環境面から製造時にＣＯ２排出の少ないセメントや廃棄物を有効利用したセメントを用いたコンクリートが種々検討されるようになった。 In recent years, demand for concrete is expected to increase in the fields of civil engineering, architecture, etc. due to the increase or enlargement of structures using concrete and the need to repair or reinforce aging structures.
On the other hand, from an environmental perspective, various types of concrete using cement that emit less CO 2 during production and cement that effectively utilizes waste materials have been studied.
　例えば、特許文献１では、コンクリートの混和材として使用した場合に、コンクリートの配合あるいは調合の大幅な見直しを行わずに流動性の経時変化の低減及び材料分離抵抗性の向上を低コストで実現できるコンクリート組成物用微粉末が提案されている。 For example, 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.
特許第４８１０９１４号公報Patent No. 4810914
　特許文献１に記載のコンクリート組成物用微粉末は、生石灰微粉末及び／又は消石灰微粉末を遊離酸化カルシウム換算で０．０質量％より多く且つ１．０質量％未満含有し、炭酸カルシウム微粉末を９５．０質量％以上含有するものである。しかし、凝結性や初期強度、乾燥収縮性状といった基本的な評価がなく、実用性に疑問が残るものといえる。 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. However, there are no basic evaluations such as setting properties, initial strength, and drying shrinkage properties, and the practicality of this method is questionable.
　本発明は、上記のような問題を解決するためになされたものであり、初期強度発現性が良好であり、また、良好な凝結性および乾燥収縮性状を確保することができる、セメント混和材を提供することを目的とする。 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.
　本発明者らは、上記のような問題を解決するために鋭意研究を行った結果、一粒子中に、炭酸カルシウム及び水酸化カルシウムを含み、これらの質量比を所定の範囲とし、炭酸カルシウム及び水酸化カルシウムの合計含有率を高くしたセメント混和材が上記課題を解決できることを見出し、本発明を完成するに至った。
　すなわち、本発明は、下記のとおりである。 As a result of intensive research to solve the above problems, the present inventors found that 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.
［１］　一粒子中に、炭酸カルシウム及び水酸化カルシウムを含むセメント混和材であって、前記炭酸カルシウムと前記水酸化カルシウムの質量比（炭酸カルシウム／水酸化カルシウム）が３０／７０～９７／３であり、前記炭酸カルシウム及び前記水酸化カルシウムの合計が前記セメント混和材中５０質量％以上であるセメント混和材。
［２］　前記セメント混和材と水とを質量比で１：３００の割合で混合した混合液において、ｐＨ８からｐＨ１１に至るまでに要する時間が、１０～３０秒である［１］に記載のセメント混和材。
［３］　副生消石灰の炭酸化物である［１］又は［２］に記載のセメント混和材。
［４］　メジアン径が２０～６０μｍである［１］～［３］のいずれか１つに記載のセメント混和材。
［５］　［１］～［４］のいずれか１つに記載のセメント混和材とセメントとを含むセメント組成物。
［６］　前記セメントが高炉セメントである［５］に記載のセメント組成物。 [1] A cement admixture containing calcium carbonate and calcium hydroxide in one particle, wherein the mass ratio of the calcium carbonate to the calcium hydroxide (calcium carbonate/calcium hydroxide) is 30/70 to 97/3. and a cement admixture in which the total of the calcium carbonate and the calcium hydroxide is 50% by mass or more in the cement admixture.
[2] 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 μm.
[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.
　本発明によれば、初期強度発現性が良好であり、また、良好な凝結性および乾燥収縮性状を確保することができる、セメント混和剤を提供することができる。 According to the present invention, it is possible to provide a cement admixture that has good initial strength development properties and can ensure good setting and drying shrinkage properties.
セメント混和材Ａ及びセメント混和材ＢのｐＨ測定の結果を示す図である。It is a figure which shows the result of pH measurement of cement admixture A and cement admixture B.
　以下、本発明の一実施形態（本実施形態）について詳細に説明する。なお、本明細書で使用する部や％は特に規定のない限り質量基準である。 Hereinafter, one embodiment of the present invention (this embodiment) will be described in detail. Note that parts and percentages used in this specification are based on mass unless otherwise specified.
［セメント混和材］
　本実施形態に係るセメント混和材は、一粒子中に、炭酸カルシウム及び水酸化カルシウムを含む。炭酸カルシウムと水酸化カルシウムとが１つの粒子中に共存することで、これらが別々に存在する場合に比べて、良好な初期強度発現性を得ることができる。一方で、炭酸カルシウム及び水酸化カルシウムをそれぞれ粉末で混合した状態では、アルカリ分の溶出に偏りが生じるため、良好な初期強度発現効果が得られにくいと考えられる。 [Cement admixture]
The cement admixture according to this embodiment contains calcium carbonate and calcium hydroxide in one particle. When calcium carbonate and calcium hydroxide coexist in one particle, it is possible to obtain better initial strength development than when they exist separately. On the other hand, in a state in which calcium carbonate and calcium hydroxide are mixed in the form of powders, the elution of alkali components is uneven, so it is thought that it is difficult to obtain a good initial strength development effect.
　炭酸カルシウムと水酸化カルシウムの質量比（炭酸カルシウム／水酸化カルシウム）は、３０／７０～９７／３であり、５０／５０～９０／１０であることが好ましく、７０／３０～８５／１５であることがより好ましい。当該質量比が３０／７０未満、または９７／３を超えると、良好な初期強度発現性や凝結性状が得られにくくなる。 The mass ratio of calcium carbonate to calcium hydroxide (calcium carbonate/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.
　炭酸カルシウム及び水酸化カルシウムの合計は、セメント混和材中５０質量％以上であり、７０質量％以上であることが好ましく、９０質量％以上であることがより好ましい。当該合計が５０質量％未満であると、良好な初期強度発現性が得られにくくなる。なお、当該合計の上限は、９５質量％である。 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.
　本実施形態に係るセメント混和材は既述のとおり、一粒子中に炭酸カルシウム及び水酸化カルシウムを含むものでその混在状態としては、特に限定されるものではないが、例えば、中心に水酸化カルシウムが主として存在し、外側に炭酸カルシウムが主として存在するコアシェル構造であることが好ましい。コアシェル構造であることで、まず外側に多く存在する炭酸カルシウムが過剰なカルシウムの溶出を抑制し、その後、中心付近に多く存在する水酸化カルシウムが段階的にカルシウムを溶出することで、良好な初期強度発現性が得られやすくなり、また、良好な凝結性及び乾燥収縮性状の確保がよりしやすくなる。 As described above, 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.
　上記のコアシェル構造と関連して、本実施形態に係るセメント混和材は、当該セメント混和材と水とを質量比で１：３００の割合で混合した混合液において、ｐＨ８からｐＨ１１に至るまでに要する時間が、１０～３０秒であることが好ましく、１３～２５秒であることがより好ましい。このような態様は、当該セメント混和材がコアシェル構造となっていることを推察させる。すなわち、上記混合液において、まずは表面に多く存在する炭酸カルシウムが溶解する。炭酸カルシウムは水酸化カルシウムよりもｐＨは低いため、混合液作製の直後からしばらく（例えば、５～１０秒後まで）は、ｐＨは８～９付近を示す。その後、中心側の水酸化カルシウムが溶出すると、ｐＨが高くなりはじめて最終的に１１付近を示すようになる。 In relation to the above-mentioned core-shell structure, 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. Such an aspect suggests that 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.
　一方、炭酸カルシウム粉末だけの場合の混合液のｐＨは、３０秒経過してもｐＨは８付近であり、水酸化カルシウムと炭酸カルシウムをそれぞれ等量混合してなる混合液は、水酸化カルシウムの強塩基性が支配的であるため、混合液作製の直後から、ｐＨが高くなり１０秒程度でｐＨ１１付近まで高くなる。
　このように、本実施形態に係るセメント混和材において、既述のとおり、ｐＨ８からｐＨ１１に至るまでに要する時間が、１０～３０秒程度であることは、コアシェル構造を有していると推察され、より効率よく良好な初期強度発現性が得られやすくなり、また、より良好な凝結性及び乾燥収縮性状の確保が可能となる。 On the other hand, 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.
　なお、ｐＨの測定は、純水３００ｍｌ（３００ｇ）をスターラーで攪拌させながら、試料１ｇを粉塵が生じない程度に一気に投入し、その投入後、１秒ごとのｐＨ変化を、ｐＨメーターにより測定すればよい。このときの撹拌速度は、６００ｒｐｍ、測定時の水温は２０℃とする。試料はブレーン比表面積で４５００～４７００ｃｍ２／ｇのものを使用することが好ましい。なお、ブレーン比表面積とは、ＪＩＳ　Ｒ　５２０１「セメントの物理試験方法」に記載された比表面積試験に基づいて測定されたものである。 To measure the pH, add 1 g of the sample at once to 300 ml (300 g) of pure water while stirring it with a stirrer to the extent that no dust is generated, and then measure the pH change every second with a pH meter. Bye. The stirring speed at this time is 600 rpm, and the water temperature at the time of measurement is 20°C. It is preferable to use a sample having a Blaine specific surface area of 4500 to 4700 cm 2 /g. The Blaine specific surface area is measured based on the specific surface area test described in JIS R 5201 "Physical Test Methods for Cement."
　混和材使用時の流動性、および均一な混和材粒子の分散により良好な初期強度発現性を確報する観点から、本実施形態に係るセメント混和材のメジアン径は、２０～６０μｍであることが好ましく、２５～５０μｍであることがより好ましい。メジアン径は、例えば、ＨＯＲＩＢＡ社製のレーザー回折／散乱式粒子径分布測定装置を用いることで求めることができる。 From the viewpoint of ensuring good initial strength development due to fluidity when using the admixture and uniform dispersion of admixture particles, the median diameter of the cement admixture according to this embodiment is preferably 20 to 60 μm. , more preferably 25 to 50 μm. The median diameter can be determined, for example, by using a laser diffraction/scattering particle size distribution measuring device manufactured by HORIBA.
　以上のようなセメント混和材は、粒度調整を行った市販の消石灰を炭酸化して作製することができるが、本実施形態では、廃棄物の有効利用と、炭酸カルシウム及び水酸化カルシウムの質量比の調整のしやすさといった観点から、副生消石灰の炭酸化物である炭酸化副生消石灰を用いることが好ましい。 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.
　炭酸化副生消石灰の原料となる副生消石灰は、カルシウムカーバイド法によるアセチレンガスの製造工程で副生される副生消石灰（アセチレンガス製造方法の違いで、湿式品と乾式品がある）、カルシウムカーバイド電気炉の湿式集塵工程で捕獲されるダスト中に含まれる副生消石灰等といったアセチレン副生消石灰が挙げられる。副生消石灰は、例えば、水酸化カルシウムが６５～９５％（好ましくは、７０～９０％）で、その他に、炭酸カルシウムを０．１～１０％、酸化鉄を０．１～６．０％（好ましくは、０．１～３．０％）等を含む。これらの割合は蛍光Ｘ線測定、及び示差熱重量分析（ＴＧ－ＤＴＡ）で求まる質量減量分（Ｃａ（ＯＨ）２：４０５℃～５１５℃付近、ＣａＣＯ３：６５０℃～７６５℃付近）にて確認することができる。レーザー回折・散乱法で測定する体積平均粒子径は、５０～１００μｍ程度である。さらに、ＪＩＳ　Ｋ００６８「化学製品の水分測定方法」中、乾燥減量法で測定される水分率は、１０％以下であることが好ましい。また、ＣａＳ、Ａ１２Ｓ３、及びＣａＣ２・ＣａＳなどイオウ化合物を含んでもよいが、２％以下であることが好ましい。 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. For example, 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%). These ratios are determined by the mass loss (Ca(OH) 2 : around 405°C to 515°C, CaCO 3 : around 650°C to 765°C) determined by fluorescent X-ray measurement and differential thermogravimetry analysis (TG-DTA). It can be confirmed. The volume average particle diameter measured by laser diffraction/scattering method is about 50 to 100 μm. Furthermore, the moisture content measured by the loss on drying method in JIS K0068 "Method for measuring moisture in chemical products" is preferably 10% or less. Sulfur compounds such as CaS, A1 2 S 3 , and CaC 2 ·CaS may also be included, but the content is preferably 2% or less.
　また、この副生消石灰のブレーン比表面積は、２５００～６０００ｃｍ２／ｇであることが好ましく、３０００～５５００ｃｍ２／ｇであることがより好ましい。２５００～６０００ｃｍ２／ｇであることで、所望の炭酸化処理がしやすくなる。 Further, 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.
　副生消石灰のメジアン径は、取り扱い性の観点から、１～３００μｍであることが好ましく、１０～１００μｍであることがより好ましい。 From the viewpoint of handleability, the median diameter of the by-product slaked lime is preferably 1 to 300 μm, more preferably 10 to 100 μm.
　副生消石灰の炭酸化は、例えば、副生消石灰を二酸化炭素含有ガス雰囲気中で０～７５℃の範囲下に置き、必要に応じて加熱及び／又は加湿する方法が挙げられる。 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.
　二酸化炭素含有ガスとしては、セメント工場及び石炭火力発電所から発生する排ガス、塗装工場における排気処理で発生する排ガス等を用いることができ、その場合は加熱や加湿等は不要となる。二酸化炭素含有ガス中の二酸化炭素の割合は、５体積％以上であることが好ましく、１０～１００体積％であることが好ましく、１５～１００体積％であることがさらに好ましい。 As the carbon dioxide-containing gas, exhaust gas generated from cement factories and coal-fired power plants, exhaust gas generated during exhaust treatment at paint factories, etc. can be used, and in that case, heating, humidification, etc. are not required. 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.
　二酸化炭素含有ガス中には水分（水蒸気）が含まれていてもよい。例えば、２０℃における相対湿度が８０％ＲＨ以上であることが好ましく、９０ＲＨ％以上であることがより好ましい。 Moisture (water vapor) may be included in the carbon dioxide-containing gas. For example, the relative humidity at 20° C. is preferably 80% RH or more, more preferably 90 RH% or more.
　二酸化炭素の濃度や温度、湿度、炭酸化の時間等を調整することで副生消石灰の炭酸化の割合を調整できる。そのため、主成分の水酸化カルシウムの表面が炭酸化されて炭酸化カルシウムとなり、既述のコアシェル構造を効率よく形成することができる。また、炭酸カルシウム及び水酸化カルシウムの質量比をも容易に調整することができる。 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.
　以上のようにして作製された炭酸化副生消石灰のブレーン比表面積は、２５００～６０００ｃｍ２／ｇであることが好ましく、３０００～５５００ｃｍ２／ｇであることがより好ましく、４０００～５０００ｃｍ２／ｇであることがさらに好ましい。２５００～６０００ｃｍ２／ｇであることで、良好な初期強度発現性が得られやすくなり、また、良好な凝結性及び乾燥収縮性状の確保がよりしやすくなる。 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.
［セメント組成物］
　本実施形態に係るセメント組成物は、本実施形態のセメント混和材とセメントとを含む。 [Cement composition]
The cement composition according to this embodiment includes the cement admixture of this embodiment and cement.
　本実施形態に係るセメントとしては、特に限定されないが、例えば、普通、早強、中庸熱、低熱、白色などの各種ポルトランドセメント；都市ゴミ焼却灰、下水汚泥焼却灰を原料として製造されるエコセメント；高炉スラグ、シリカヒューム、石灰石、フライアッシュ、石膏などを含む混合セメントなどが挙げられる。
　なかでも、良好な初期強度発現性を得られるセメントとして、ポルトランドセメント、高炉セメントが好ましく、高炉セメントがより好ましい。 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.
　セメント組成物には、本発明の効果を阻害しない範囲において、一般的に配合され得る公知の添加剤を含有することができる。添加剤としては、特に限定されないが、防錆剤、着色剤、ポリマー、繊維、流動化剤、中性化抑制剤、防水剤、増粘剤、防水剤、遅延剤、早強剤、促進剤、減水剤、高性能（ＡＥ）減水剤、起泡剤、発泡剤、ＡＥ剤、乾燥収縮低減剤、急結剤、膨張剤、耐寒促進剤、エフロレッセンス防止剤、アルカリ骨材反応抑制剤、黒色むら低減剤、環境浄化混和剤などが挙げられる。これらの添加剤は、単独又は２種以上を組み合わせて用いることができる。 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.
　セメント組成物中の本実施形態に係るセメント混和材は、当該セメント混和材の機能を有効に発揮させる観点から、１～３０質量％であることが好ましく、２～２０質量％であることがより好ましく、３～１０質量％であることがより好ましい。 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.
　本実施形態のセメント組成物はそれぞれの材料を施工時に混合して作製してもよいし、あらかじめ一部あるいは全部を混合しておいても差し支えない。また、各材料及び水の混合方法も特に限定されるものではなく、それぞれの材料を施工時に混合してもよいし、あらかじめ一部を、あるいは全部を混合しておいても差し支えない。また、材料の一部を水と混合した後に残りの材料を混合してもよい。 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.
　混合装置としては、既存のいかなる装置も使用可能であり、例えば、傾胴ミキサ、オムニミキサ、ヘンシェルミキサ、Ｖ型ミキサ、及びナウタミキサ等の使用が可能である。 As the mixing device, any existing device can be used, such as a tilting mixer, omni mixer, Henschel mixer, V-type mixer, and Nauta mixer.
　以下、実施例及び比較例を用いて本発明を具体的に説明するが、本発明はその要旨を逸脱しない限り、これらの実施例に限定されるものではない。 Hereinafter, the present invention will be specifically explained using Examples and Comparative Examples, but the present invention is not limited to these Examples unless it departs from the gist thereof.
［実験例１］
（セメント混和材の作製）
・セメント混和材Ａ
　副生消石灰として、カルシウムカーバイド法によるアセチレンガスの製造工程で副生される副生消石灰（密度：２．２１ｇ／ｃｍ３、ブレーン比表面積：４６８０ｃｍ２／ｇ、Ｃａ（ＯＨ）２含有率８４質量％）を使用し、これを下記の条件で炭酸化処理し、粉砕及び篩分けによりセメント混和材Ａ（炭酸カルシウム／水酸化カルシウム＝７５／２５（質量比）、セメント混和材Ａ中の炭酸カルシウム及び水酸化カルシウムの合計量９４質量％、密度２．５３ｇ／ｃｍ３、ブレーン比表面積４５２０ｃｍ２／ｇ、メジアン径３２μｍ）を作製した。 [Experiment example 1]
(Preparation of cement admixture)
・Cement admixture A
As by-product slaked lime, by-product slaked lime (density: 2.21 g/cm 3 , Blaine specific surface area: 4680 cm 2 /g, Ca(OH) 2 content 84 mass) is produced as a by-product in the acetylene gas production process using the calcium carbide method. %), carbonate it under the following conditions, crush it and sieve it to remove the calcium carbonate in cement admixture A (calcium carbonate/calcium hydroxide = 75/25 (mass ratio)). and a total amount of calcium hydroxide of 94% by mass, a density of 2.53 g/cm 3 , a Blaine specific surface area of 4520 cm 2 /g, and a median diameter of 32 μm).
＜炭酸化処理＞
　恒温恒湿室内で２０℃６０％ＲＨ、二酸化炭素濃度５体積％の条件で炭酸化を行った。 <Carbonation treatment>
Carbonation was performed in a constant temperature and humidity chamber at 20° C., 60% RH, and a carbon dioxide concentration of 5% by volume.
・セメント混和材Ｂ
　石灰石微粉末（上越鉱業製、１００メッシュ、密度：２．７４ｇ／ｃｍ３、比表面積：４５５０ｃｍ２／ｇ）と既述の副生消石灰とを、セメント混和材Ｂ中の炭酸カルシウム／水酸化カルシウムが７５／２５（質量比）となるように混合し、篩分けを行ってセメント混和材Ｂ（炭酸カルシウム／水酸化カルシウム＝７５／２５（質量比）、セメント混和材Ｂ中の炭酸カルシウム及び水酸化カルシウムの合計量９９質量％、密度２．６１ｇ／ｃｍ３、ブレーン比表面積４５２０ｃｍ２／ｇ、メジアン径２１μｍ）を作製した。 ・Cement admixture B
Fine limestone powder (manufactured by Joetsu Mining Co., Ltd., 100 mesh, density: 2.74 g/cm 3 , specific surface area: 4550 cm 2 /g) and the aforementioned by-product slaked lime were added to calcium carbonate/calcium hydroxide in cement admixture B. were mixed so that the ratio was 75/25 (mass ratio), and sieved to obtain cement admixture B (calcium carbonate/calcium hydroxide = 75/25 (mass ratio)), calcium carbonate and water in cement admixture B. 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 μm).
・セメント混和材Ｃ
　既述の副生消石灰をセメント混和材Ｃ（炭酸カルシウム／水酸化カルシウム＝０／１００（質量比）、セメント混和材Ｃ中の炭酸カルシウム及び水酸化カルシウムの合計量９１質量％、密度２．２１ｇ／ｃｍ３、ブレーン比表面積４６８０ｃｍ２／ｇ、メジアン径４７μｍ）とした。 ・Cement admixture C
The already mentioned by-product slaked lime was added to cement admixture C (calcium carbonate/calcium hydroxide = 0/100 (mass ratio), total amount of calcium carbonate and calcium hydroxide in cement admixture C 91% by mass, density 2.21g) /cm 3 , Blaine specific surface area 4680 cm 2 /g, and median diameter 47 μm).
（各混和材のｐＨ測定）
　セメント混和材Ａ、ＢのそれぞれをＨＯＲＩＢＡ社製のｐＨ測定計（Ｄ－５３Ｓ）を用いて測定した。具体的には、純水３００ｍｌ（３００ｇ）をスターラーで攪拌させながら、試料１ｇを粉塵が生じない程度に一気に投入し、その投入後、１秒ごとのｐＨ変化を、ｐＨメーターにより測定した。このときの撹拌速度は、６００ｒｐｍ、測定時の水温は２０℃とした。結果を図１に示す。 (pH measurement of each admixture)
Each of cement admixtures A and B was measured using a pH meter (D-53S) manufactured by HORIBA. Specifically, while stirring 300 ml (300 g) of pure water with a stirrer, 1 g of the sample was added at once to such an extent that no dust was generated, and after the addition, the pH change every second was measured using a pH meter. The stirring speed at this time was 600 rpm, and the water temperature at the time of measurement was 20°C. The results are shown in Figure 1.
　図１より、セメント混和材Ａは、ｐＨ８からｐＨ１１に至るまでに要する時間が、１５秒で、１０～３０秒の範囲内にあった。一方で、セメント混和材ＢはｐＨ８からｐＨ１１に至るまでに要する時間が、７秒で、セメント混和材ＡよりもｐＨの上昇が速かった。 From FIG. 1, 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. On the other hand, 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.
（セメント組成物の作製と評価）
　各例のセメント混和材とセメントとからなるセメント組成物に砂を混合し、水／　セメント＝０．５（質量比）となるように水（上下水道水）を混合して、下記の評価を行った。結果を表１に示す。なお、セメント混和材は、セメント組成物中に５％となるように混合し、セメント１００部に対して砂を３００部混合した。また、使用した材料は下記のとおりである。
・セメント：Ｂ種高炉セメント（市販品、密度３．０５ｇ／ｃｍ３、ブレーン比表面積３７００ｃｍ２／ｇ、スラグ置換率：４２．８％）
・砂：細骨材（セメント協会製、ＪＩＳ強さ試験用標準砂）
・水：　 (Preparation and evaluation of cement composition)
Sand was mixed with the cement composition consisting of the cement admixture and cement in each example, and water (water supply and sewage water) was mixed so that the water/cement ratio was 0.5 (mass ratio), and the following evaluation was carried out. went. The results are shown in Table 1. The cement admixture was mixed into the cement composition at a concentration of 5%, and 300 parts of sand was mixed with 100 parts of cement. In addition, the materials used are as follows.
・Cement: Class B blast furnace cement (commercial product, density 3.05 g/cm 3 , Blaine specific surface area 3700 cm 2 /g, slag replacement rate: 42.8%)
・Sand: Fine aggregate (manufactured by Cement Association, JIS strength test standard sand)
·water:
・圧縮強さ
　ＪＩＳ　Ｒ　５２０１「セメントの物理試験方法」に準拠し材齢３日、７日、２８日での強さを測定した。なお、脱型後は水中養生を実施した。 - Compressive strength The strength was measured at 3 days, 7 days, and 28 days in accordance with JIS R 5201 "Physical test method for cement." Note that after demolding, water curing was performed.
・凝結
　ＪＩＳ　Ｒ　５２０１「セメントの物理試験方法」に準拠して、凝結の始発及び終結の時間を測定した。 - Setting The starting and ending times of setting were measured in accordance with JIS R 5201 "Physical Test Methods for Cement."
・乾燥収縮
　ＪＩＳ　Ａ　１１２９「モルタル及びコンクリートの長さ変化測定方法」の附属書Ａモルタル及びコンクリートの乾燥による自由収縮ひずみ試験方法に準拠して、材齢２８日目の長さ変化率を測定した。 ・Drying shrinkage The length change rate on the 28th day of material age was measured in accordance with JIS A 1129 "Length change measurement method for mortar and concrete", Annex A Free shrinkage strain test method due to drying of mortar and concrete. .
Figure JPOXMLDOC01-appb-T000001
 
Figure JPOXMLDOC01-appb-T000001
 
　一粒子中に炭酸カルシウム及び水酸化カルシウムを所定の割合で含むセメント混和材Ａは、良好な凝結性および乾燥収縮性状を確保しながら、他の混和材に比べて、材齢３日の初期強度発現性が良好であった。 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.
［実験例２］
　セメント混和材Ａの作製において、炭酸化条件を変更して表２に示す、炭酸カルシウム／水酸化カルシウム質量比としたセメント混和材を作製し、実験例１と同様にして、セメント組成物の作製と評価を行った。結果を表２に示す。 [Experiment example 2]
In the production of cement admixture A, the carbonation conditions were changed to produce a cement admixture with the calcium carbonate/calcium hydroxide mass ratio shown in Table 2, and in the same manner as in Experimental Example 1, a cement composition was produced. and evaluated. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
 
Figure JPOXMLDOC01-appb-T000002
 
［実験例３］
　セメント混和材Ａの作製において、粉砕及び篩分けにより表２に示すメジアン径としたセメント混和材を作製し、実験例１と同様にして、セメント組成物の作製と評価を行った。結果を表２に示す。 [Experiment example 3]
In the preparation of cement admixture A, a cement admixture having the median diameter shown in Table 2 was prepared by crushing and sieving, and a cement composition was prepared and evaluated in the same manner as in Experimental Example 1. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000003
 
Figure JPOXMLDOC01-appb-T000003
 
　本発明は、特に土木分野、建築分野等で用いられるセメント混和材として好適に使用できる。 The present invention can be particularly suitably used as a cement admixture used in the civil engineering field, construction field, etc.

Claims (6)

  1. 　一粒子中に、炭酸カルシウム及び水酸化カルシウムを含むセメント混和材であって、
    　前記炭酸カルシウムと前記水酸化カルシウムの質量比（炭酸カルシウム／水酸化カルシウム）が３０／７０～９７／３であり、
    　前記炭酸カルシウム及び前記水酸化カルシウムの合計が前記セメント混和材中５０質量％以上であるセメント混和材。     A cement admixture containing calcium carbonate and calcium hydroxide in one particle,
    The mass ratio of the calcium carbonate and the calcium hydroxide (calcium carbonate/calcium hydroxide) is 30/70 to 97/3,
    A cement admixture in which the total amount of the calcium carbonate and the calcium hydroxide is 50% by mass or more in the cement admixture.
  2. 　前記セメント混和材と水とを質量比で１：３００の割合で混合した混合液において、ｐＨ８からｐＨ１１に至るまでに要する時間が、１０～３０秒である請求項１に記載のセメント混和材。 The cement admixture according to claim 1, wherein the time required for the cement admixture and water to reach pH 11 from pH 8 to pH 11 is 10 to 30 seconds in a mixed solution in which the cement admixture and water are mixed at a mass ratio of 1:300.
  3. 　副生消石灰の炭酸化物である請求項１又は２に記載のセメント混和材。 The cement admixture according to claim 1 or 2, which is a carbonate of by-product slaked lime.
  4. 　メジアン径が２０～６０μｍである請求項１又は２に記載のセメント混和材。 The cement admixture according to claim 1 or 2, which has a median diameter of 20 to 60 μm.
  5. 　請求項１又は２に記載のセメント混和材とセメントとを含むセメント組成物。 A cement composition comprising the cement admixture according to claim 1 or 2 and cement.
  6. 　前記セメントが高炉セメントである請求項５に記載のセメント組成物。 The cement composition according to claim 5, wherein the cement is blast furnace cement.
PCT/JP2023/029727 2022-08-26 2023-08-17 Cement admixture and cement composition WO2024043169A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59203121A (en) * 1983-04-08 1984-11-17 Giken Kogyo Kk Construction of anchor body
US6310129B1 (en) * 1997-10-02 2001-10-30 Rebaseproducts Inc. Processing and use of carbide lime
WO2013053064A1 (en) * 2011-10-13 2013-04-18 Martin Marcus E Method and apparatus for the preparation of calcium carbonate coated calcium hydroxide particles

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59203121A (en) * 1983-04-08 1984-11-17 Giken Kogyo Kk Construction of anchor body
US6310129B1 (en) * 1997-10-02 2001-10-30 Rebaseproducts Inc. Processing and use of carbide lime
WO2013053064A1 (en) * 2011-10-13 2013-04-18 Martin Marcus E Method and apparatus for the preparation of calcium carbonate coated calcium hydroxide particles

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