Cement composition and hydraulic composition

Abstract

To provide a cement composition that includes, as a cement admixture, a ground product of a burned product (those not corresponding to cement clinker ground product), has excellent strength development, and can reduce a total amount of discharged carbon dioxide by absorbing and immobilizing abundant carbon dioxide in the curing process: and a hydraulic composition involving the cement composition.SOLUTION: Disclosed are: a powdery cement composition (A) that includes (i) Portland cement or Portland cement clinker ground product and (ii) a ground product of a burned product involving 2CaOSiO2 and 2CaOAl2O3SiO2, the ground product of the burned product satisfying following conditions (1) and (2), and a cement composition (B) that includes (iii) an amine, wherein (1) an amount of the 2CaOAl2O3SiO2 to 100 pts.mass of the 2CaOSiO2 is 10-100 pts.mass, and (2) the burned product does not contain 3CaOAl2O3, or contains it in an amount of 15 pts.mass or under relative to 100 pts.mass of the 2CaOSiO2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a cement composition and a hydraulic composition containing the cement composition. [Background technology]

[0002] Currently, reducing carbon dioxide emissions is a crucial issue in order to curb global warming. One known method for reducing carbon dioxide emissions in the production of cementitious hardened bodies is to absorb carbon dioxide during the curing process of the cementitious hardened body, thereby reducing the total amount of carbon dioxide emitted until the cementitious hardened body is obtained. Patent Document 1 describes a cementitious hardened body that can significantly reduce the total amount of carbon dioxide emitted by absorbing a large amount of carbon dioxide during the curing process, characterized in that the hardened body of a cement mixture containing (A) a powder for cement mixing containing either or both of mullite and anorthite, and a powdered cement composition containing Portland cement, (B) water, and (C) aggregate is carbonized. Furthermore, Patent Document 2 describes a cementitious hardened body characterized by carbonation of a cement mixture containing (A) 10 to 200 parts by mass of C2AS and 20 parts by mass or less of C3A per 100 parts by mass of C2S, a powdered cement composition containing Portland cement, (B) water, and (C) aggregate. This cementitious hardened body is characterized by carbonization of a cement mixture containing these materials.

[0003] On the other hand, cement compositions using crushed calcined material (not crushed cement clinker) as a cement admixture are known. For example, as a fired product (cement admixture) that can reduce the heat of hydration of cement and improve its fluidity, Patent Document 3 describes a fired product characterized by containing 10 to 100 parts by weight of C2AS and a C3A content of 20 parts by weight or less per 100 parts by weight of C2S. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-153357 [Patent Document 2] Japanese Patent Publication No. 2016-47788 [Patent Document 3] Japanese Patent Publication No. 2004-2155 [Overview of the project] [Problems that the invention aims to solve]

[0005] The object of the present invention is to provide a cement composition that contains crushed calcined material (not crushed cement clinker) as a cement admixture, exhibits excellent strength development, and can reduce the total amount of carbon dioxide emitted by absorbing and fixing a large amount of carbon dioxide during the curing process, as well as a hydraulic composition containing the cement composition. [Means for solving the problem]

[0006] The inventors of the present invention have diligently studied to solve the above problems and have found that the above objectives can be achieved by a cement composition comprising (A)(i) crushed Portland cement or Portland cement clinker, (ii) crushed calcined material containing 2CaO·SiO2 and 2CaO·Al2O3·SiO2 that satisfies specific conditions, and (iv) an alkaline earth metal-containing material which is at least one selected from periclase, light-calcined magnesia, partially hydrated light-calcined magnesia, light-calcined dolomite, and partially hydrated light-calcined dolomite, and which contains magnesium in a proportion of 1.7 to 5.0% by mass (on an oxide basis), wherein the total content of free calcium oxide and the content of magnesium (Mg) contained in the alkaline earth metal-containing material on an oxide basis is 2.0 to 5.3% by mass, and (ii) the content of crushed calcined material is 10 to 90% by mass. In other words, the present invention provides the following [1] to [8].

[0007] [1] (A)(i) Crushed Portland cement or Portland cement clinker, (ii) Crushed calcined product containing 2CaO·SiO2 and 2CaO·Al2O3·SiO2 that satisfies the following conditions (1) to (2), and (iv) Cement composition containing alkaline earth metal (however, limited to those other than those in (i) and (ii) above), wherein the alkaline earth metal contained in the alkaline earth metal, is magnesium (Mg), and the alkaline earth metal contained in the alkaline earth metal is periclase, calcined magnesia, or a portion of calcined magnesia. A cement composition characterized by comprising at least one selected from hydrate, light-calcined dolomite, and partially hydrated light-calcined dolomite, wherein the total content of free calcium oxide and the content of magnesium (Mg) in the alkaline earth metal-containing material on an oxide basis in the cement composition is 2.0 to 5.3% by mass, the content of magnesium (Mg) in the alkaline earth metal-containing material on an oxide basis in the cement composition is 1.7 to 5.0% by mass, and the content of the crushed calcined material in the cement composition is 10 to 90% by mass. (1) The amount of the above 2CaO·Al2O3·SiO2 with respect to 100 parts by mass of the above 2CaO·SiO2 is 10 to 100 parts by mass (2) The fired product does not contain 3CaO·Al2O3, or contains it in an amount of 15 parts by mass or less with respect to 100 parts by mass of the above 2CaO·SiO2

[0008] [2] The cement composition according to [1] above, wherein the magnesium contained in the alkaline earth metal-containing substance is at least one form selected from magnesium oxide, magnesium hydroxide, magnesium sulfate, magnesium nitrate, and magnesium chloride. [3] A hydraulic composition containing the cement composition according to [1] or [2] above, water, and an aggregate, wherein the amount of the water with respect to 100 parts by mass of the above cement composition is 25 to 70 parts by mass. [4] Further, the cement composition according to [1] or [2] above, which contains (B)(iii) an amine, and the amount of the amine with respect to 100 parts by mass of the total of (i) and (ii) above is 0.5 to 2.0 parts by mass. [5] The cement composition according to [4] above, wherein the amine is an alkanolamine. [6] A hydraulic composition containing the cement composition according to [4] or [5] above, water, and an aggregate, wherein the amount of the water with respect to 100 parts by mass of the total of (i) and (ii) above is 25 to 70 parts by mass.

[0009] [7] A method for producing the hydraulic composition according to [3] above, which includes a kneaded material preparation step of preparing a kneaded material, which is a mixture of each material constituting the cement composition, the water, and the aggregate, a placing step of placing the kneaded material in a mold, a demolding step of demolding the hardened body of the kneaded material from the mold after the kneaded material in the mold has hardened, and a carbonation curing step of carbonation curing the hardened body of the kneaded material demolded from the mold to obtain a carbonation hardened body. [8] A method for producing the hydraulic composition according to [6], comprising a kneaded material preparation step of preparing a kneaded material, which is a mixture of each material constituting the cement composition, the water, and the aggregate; a placing step of placing the kneaded material in a mold; a demolding step of demolding the cured body of the kneaded material from the mold after the kneaded material in the mold has cured; and a carbonation curing step of subjecting the cured body of the kneaded material demolded from the mold to carbonation curing to obtain a carbonated cured body.

Advantages of the Invention

[0010] When water is added to the cement composition of the present invention to form a cured body, it has excellent strength development properties. In addition, when carbonation curing or the like is performed during the curing process when water is added to the cement composition of the present invention to form a cured product, a large amount of carbon dioxide can be absorbed and immobilized, thereby reducing the total amount of carbon dioxide emitted. Furthermore, by adjusting the raw material composition of the pulverized product of the (ii) fired product constituting the cement composition of the present invention and reducing the CaO content ratio compared to Portland cement, the amount of carbon dioxide emissions during production can be reduced. Also, by setting the firing temperature during the production of the fired product lower than the firing temperature during the production of Portland cement, the amount of carbon dioxide emissions generated from the fuel for firing can be reduced.

Embodiments for Carrying Out the Invention

[0011] [Cement Composition A] An example of the cement composition of the present invention is a powdery cement-containing material containing (A)(i) Portland cement or a pulverized product of Portland cement clinker and (ii) a pulverized product of a fired product containing 2CaO·SiO2 (hereinafter also referred to as "C2S") and 2CaO·Al2O3·SiO2 (hereinafter also referred to as "C2AS"), the pulverized product of the fired product satisfying the following conditions (1) to (2), and (B)(iii) a material containing an amine (hereinafter also referred to as "cement composition A"). (1) The amount of 2CaO·Al2O3·SiO2 relative to 100 parts by mass of 2CaO·SiO2 is 10 to 100 parts by mass. (2) The above-mentioned calcined product does not contain 3CaO·Al2O3 (hereinafter also referred to as "C3A"), or contains it in an amount of 15 parts by mass or less per 100 parts by mass of 2CaO·SiO2. The following explains in detail.

[0012] [(A) Ingredients: Powdered cement-containing material] The powdered cement-containing material includes (i) crushed Portland cement or Portland cement clinker, and (ii) crushed calcined material containing 2CaO·SiO2 and 2CaO·Al2O3·SiO2, which satisfies the conditions of (1) to (2) above. [(i) Components: Portland cement or crushed Portland cement clinker] Examples of Portland cement include various types such as ordinary Portland cement, rapid-hardening Portland cement, moderate-heat Portland cement, and low-heat Portland cement. Furthermore, examples of crushed Portland cement clinker include the crushed clinker of the various Portland cements mentioned above. These may be used individually or in combination of two or more types. In particular, from the viewpoint of cost and versatility, crushed ordinary Portland cement or ordinary Portland cement clinker is preferred. The specific surface area of ​​the crushed Portland cement or Portland cement clinker is preferably 2,500 to 5,000 cm². 2 / g, more preferably 3,000~4,500cm 2 The value is / g. The above Brain specific surface area is 2,500 cm². 2 If the value is 1 / g or higher, the strength development of the cement composition will be further improved. The above Blaine specific surface area is 5,000 cm². 2 If the value is less than / g, the fluidity of the cement composition before hardening will be further improved.

[0013] The content of Portland cement or crushed Portland cement clinker in the powdered cement-containing material is preferably 10 to 70% by mass, more preferably 15 to 60% by mass, even more preferably 20 to 50% by mass, and particularly preferably 25 to 40% by mass. If the above content is 10% by mass or more, the strength of the hardened body of the hydraulic composition can be increased. If the above content is 60% by mass or less, (ii) the content of crushed material in the calcined product becomes larger, and thus the reduction of carbon dioxide emissions mentioned above can be further realized. The content of Portland cement or crushed Portland cement clinker in cement composition A is preferably 10 to 70% by mass, more preferably 15 to 60% by mass, even more preferably 20 to 50% by mass, and particularly preferably 25 to 40% by mass. If the above content is 10% by mass or more, the strength of the hardened body can be increased. If the above content is 60% by mass or less, (ii) the content of crushed material in the fired product becomes larger, and thus the reduction of carbon dioxide emissions mentioned above can be further realized.

[0014] [(ii) Components: Crushed calcined material containing C2S and C2AS] In a fired product containing C2S and C2AS (hereinafter also simply referred to as "fired product"), the amount of C2AS per 100 parts by mass of C2S is 10 to 100 parts by mass, preferably 20 to 80 parts by mass, more preferably 25 to 70 parts by mass, and particularly preferably 30 to 60 parts by mass. In a fired product with an amount of less than 10 parts by mass, the carbonation of the hydraulic composition (e.g., mortar) during carbonation curing is less likely to proceed, and the amount of carbon dioxide absorbed in the early stages of curing is reduced. When the amount exceeds 100 parts by mass, the amount of C2S is relatively small, which reduces the strength development of the cement composition and also reduces the amount of carbon dioxide absorbed by the hydraulic composition in the long stages of curing. When the fired product contains C3A, the amount of C3A per 100 parts by mass of C2S is 15 parts by mass or less, preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, and particularly preferably 1 to 3 parts by mass. It is difficult to manufacture a fired product in which the above amount exceeds 15 parts by mass. Furthermore, if the above amount is 15 parts by mass or less, the fluidity of the hydraulic composition before hardening is further improved.

[0015] The calcined product may contain 4CaO·Al2O3·Fe2O3 (hereinafter also referred to as "C4AF"). The amount of C4AF relative to 100 parts by mass of C2S is preferably 30 parts by mass or less, more preferably 0.1 to 20 parts by mass, even more preferably 0.5 to 15 parts by mass, and particularly preferably 1.0 to 10 parts by mass. If the above amount is 30 parts by mass or less, the hydration activity of the hydraulic composition at its initial age can be further improved. The total amount of C4AF and C2AS relative to 100 parts by mass of C2S is preferably 10 to 100 parts by mass, more preferably 20 to 90 parts by mass, and particularly preferably 30 to 80 parts by mass. When the above amount is 10 parts by mass or more, the carbonation of the hydraulic composition (e.g., mortar) during carbonation curing progresses more easily, and the amount of carbon dioxide absorbed in the early stages of curing increases. When the above amount is 100 parts by mass or less, the amount of C2S is relatively high, which further improves the strength development of the cement composition and increases the amount of carbon dioxide absorbed by the hydraulic composition in the long stages of curing. The amount of C4AF relative to 100 parts by mass of C2AS is preferably 210 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 50 parts by mass or less, and particularly preferably 20 parts by mass or less. If the above amount is 210 parts by mass or less, the hydration activity of the hydraulic composition at its initial age can be further improved.

[0016] The C2S (B-Lite) content in the fired product is preferably 50-80% by mass, more preferably 55-75% by mass, and particularly preferably 60-70% by mass. If the above content is 50% by mass or more, the long-term strength development of the cement composition is further improved. If the above content is 80% by mass or less, the initial strength development of the cement composition is further improved. The C2AS content in the fired product is preferably 10 to 60% by mass, more preferably 20 to 50% by mass, and particularly preferably 25 to 40% by mass. If the above content is 10% by mass or more, the carbonation of the hydraulic composition will proceed more easily, and the amount of carbon dioxide absorbed by the hydraulic composition in the early stages of aging will be greater. If the above content is 60% by mass or less, the amount of C2S will be relatively large, which will further improve the strength development of the cement composition and increase the amount of carbon dioxide absorbed by the hydraulic composition in the long stages of aging.

[0017] The C3A (aluminate phase) content in the calcined product is preferably 10% by mass or less, more preferably 0.1 to 5% by mass, and particularly preferably 0.5 to 3.5% by mass. If the above content is 10% by mass or less, the fluidity of the hydraulic composition before hardening is further improved. The content of C4AF (ferrite phase) in the calcined product is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less. If the above content is 20% by mass or less, the hydration activity of the hydraulic composition at its initial age can be further improved. The content of C3S (alite; 3CaO·SiO2) in the calcined product is preferably 5% by mass or less, more preferably 3% by mass or less, and particularly preferably 1% by mass or less. If the above content is 5% by mass or less, the fluidity of the hydraulic composition before hardening can be further improved.

[0018] The CaO content in the calcined product (especially when limestone is used as a raw material) is preferably 50-59% by mass, more preferably 52-58% by mass, and most preferably 53-57% by mass. If the above percentage is 50% by mass or more, the strength development of the cement composition is improved. If the above percentage is 59% by mass or less, the amount of carbon dioxide emitted during calcination can be further reduced. The SiO2 content in the calcined product is preferably 15 to 45% by mass, more preferably 20 to 40% by mass, and particularly preferably 25 to 35% by mass. The Al2O3 content in the calcined product is preferably 1 to 10% by mass, more preferably 3 to 9% by mass, and particularly preferably 4 to 8% by mass. The Fe2O3 content in the calcined product is preferably 1 to 8% by mass, more preferably 2 to 6% by mass, and particularly preferably 3 to 5% by mass.

[0019] The mineral composition of calcined materials (content of C2S, C2AS, C3A, and C4AF, etc.) can be quantified using X-ray diffraction (XRD) / Rietveld method. Specifically, the theoretical profile of each mineral can be fitted to the powder X-ray diffraction chart (measured profile) of the calcined material and quantified by Rietveld analysis. Commercially available analysis software can be used for this quantification. The mineral composition can also be quantified by microscopic observation or point counting using electron backscatter diffraction.

[0020] The above-mentioned calcined product can be manufactured by, for example, using one or more materials selected from industrial waste, general waste, and construction-generated soil as raw materials, preparing the raw materials to achieve the target mineral composition, chemical composition, etc. of the calcined product, and then calcining these raw materials at, for example, 1,000 to 1,400°C (preferably 1,200 to 1,400°C, and more preferably 1,300 to 1,400°C). Furthermore, if it is difficult to prepare the calcined product to achieve the target mineral composition using only the above-mentioned raw materials, other raw materials such as calcium (e.g., limestone), silicon, aluminum, and iron may also be used. The resulting calcined material is appropriately pulverized using a pulverizer such as a ball mill or rod mill. If the powdered cement contains gypsum, the calcined material and the gypsum may be pulverized and mixed together simultaneously. The Blaine specific surface area of ​​the calcined material is preferably 2,500 to 5,000 cm². 2 / g, more preferably 3,000~4,500cm 2 The value is / g. The above Brain specific surface area is 2,500 cm². 2 If the concentration is above / g, the hydration reaction is further promoted, carbon dioxide absorption increases, and the strength development of the cement composition is further improved. 2 If the value is less than / g, the fluidity of the hydraulic composition before hardening will be further improved.

[0021] The content of crushed calcined material in the powdered cement is preferably 10 to 90% by mass, more preferably 30 to 85% by mass, even more preferably 40 to 80% by mass, even more preferably 50 to 80% by mass, and particularly preferably 60 to 80% by mass. If the above content is 10% by mass or more, the amount of carbon dioxide absorbed by the hydraulic composition in the initial age will be greater. If the above amount is 90% by mass or less, the decrease in the strength development of the cement composition due to the relatively small amount of Portland cement or crushed Portland cement clinker will be less likely to occur. The amount of crushed calcined material per 100 parts by mass of crushed Portland cement or crushed Portland cement clinker is preferably 65 to 500 parts by mass, more preferably 100 to 400 parts by mass, even more preferably 150 to 350 parts by mass, and particularly preferably 200 to 320 parts by mass. If the above amount is 65 parts by mass or more, the amount of carbon dioxide absorbed by the hydraulic composition in the initial age will be greater. If the above amount is 500 parts by mass or less, the decrease in the strength development of the cement composition due to the relatively small amount of crushed Portland cement or crushed Portland cement clinker will be less likely to occur.

[0022] Furthermore, the content of crushed calcined material in the cement composition is preferably 10 to 90% by mass, more preferably 30 to 85% by mass, even more preferably 40 to 80% by mass, even more preferably 50 to 80% by mass, and particularly preferably 60 to 80% by mass. If the above content is 10% by mass or more, the amount of carbon dioxide absorbed by the hydraulic composition in the initial age will be greater. If the above amount is 90% by mass or less, the decrease in the strength development of the cement composition due to the relatively small amount of Portland cement or crushed Portland cement clinker will be less likely to occur. (A) The ratio of the total amount of component (i) and component (ii) in the powdered cement content is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more, from the viewpoint of improving the strength development of the cement composition and increasing the amount of carbon dioxide absorbed.

[0023] [(iv) Components: Alkaline earth metal-containing material] The powdered cement-containing material may also contain (iv) alkaline earth metal-containing material. By including alkaline earth metal-containing material in the powdered cement-containing material, the strength development of the cement composition can be further improved. Examples of alkaline earth metals contained in alkaline earth metal-containing materials include calcium (Ca), magnesium (Mg), strontium (Sr), barium (Ba), radium (Ra), and beryllium (Be). These may be present individually or in combination of two or more. In particular, from the viewpoint of the strength development of the cement composition and ease of availability, calcium (Ca) and magnesium (Mg) are preferred, and magnesium (Mg) is more preferred. Furthermore, from the viewpoint of improving the strength development of the cement composition, the form of alkaline earth metals contained in the cement composition is preferably an oxide of alkaline earth metal or a hydroxide of alkaline earth metal, and more preferably an oxide of alkaline earth metal.

[0024] When an alkaline earth metal-containing material contains magnesium as the alkaline earth metal, examples of magnesium sources (magnesium-containing substances) include magnesium oxide, magnesium hydroxide, magnesium sulfate, magnesium nitrate, and magnesium chloride. Among these, magnesium oxide and magnesium hydroxide are preferred, and magnesium oxide is more preferred, from the viewpoint of further improving the strength development of the cement composition. These may be reagents, but they may also be magnesium-containing substances such as periclase (a mineral containing magnesium oxide), calcined magnesia (MgO), partially hydrated calcined magnesia, calcined dolomite (CaO·MgO), and partially hydrated calcined dolomite. These may be used individually or in combination of two or more.

[0025] When an alkaline earth metal-containing material contains calcium as the alkaline earth metal, examples of calcium sources (calcium-containing substances) include calcium oxide, calcium hydroxide, calcium nitrate, and calcium chloride. These may be reagents, or they may be calcium-containing substances such as quicklime, slaked lime, ready-mix concrete sludge, and waste concrete. These may be used individually or in combination of two or more. Among these, calcium oxide and calcium hydroxide are preferred, and calcium oxide is more preferred, from the viewpoint of further improving the strength development of the cement composition. Furthermore, the ready-mix concrete sludge is preferably a powdered form obtained by sieving the sludge generated during the concrete manufacturing process at ready-mix concrete plants and concrete product plants, using sieves or the like, to collect fine particles containing cement hydrate and unhydrated cement. The ready-mix concrete sludge is easily carbonized and usually has a CaO content of 30% by mass or more. Furthermore, the waste concrete is preferably a fine powder containing cement hydrate and unhydrated cement, obtained by crushing concrete waste generated when demolishing concrete structures, and then removing aggregate from the crushed material. The fine powder of waste concrete is easily carbonated, and the CaO content is usually 15% by mass or more. Furthermore, alkaline earth metal-containing materials are usually in powder form, from the viewpoint of improving the strength development of hydraulic compositions.

[0026] The content of alkaline earth metals in the powdered cement (however, alkaline earth metals other than the alkaline earth metals contained in the alkaline earth metal-containing material (in other words, alkaline earth metals contained in materials other than the alkaline earth metal-containing material in the powdered cement) shall be limited to magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide) is 0.1 to 10% by mass, more preferably 0.2 to 8% by mass, and particularly preferably 0.5 to 6% by mass, in terms of oxides. If the above content is less than 0.1% by mass, the strength development of the cement composition will decrease. If the above content exceeds 10% by mass, the initial strength development of the cement composition (for example, at 1 day of age) may decrease. Furthermore, if the powdered cement contains multiple alkaline earth metals (however, the only alkaline earth metals other than those contained in the alkaline earth metal-containing material are magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide), the above content rate is the total content rate.

[0027] The components (i) to (ii) and (v) to (vi) (described later) mentioned above may include periclase (MgO), magnesium hydroxide (Mg(OH)2), calcium oxide (CaO; especially free calcium oxide), calcium hydroxide (Ca(OH)2), etc. The alkaline earth metal content mentioned above shall include these alkaline earth metals in addition to the alkaline earth metals contained in the alkaline earth metal-containing material. Furthermore, alkaline earth metals (e.g., calcium) dissolved in silicate minerals (e.g., belite, alite), aluminate phase, and ferrite phase, as well as alkaline earth metals other than magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide, such as gypsum (CaSO4) and calcium carbonate, contained in components (i) to (iii) and components (v) to (vi), are unlikely to affect the effects of the present invention, or they are present in such small amounts that they hardly affect the effects of the present invention. The content of periclase (MgO) and magnesium hydroxide (Mg(OH)2) in components (i) to (ii), and components (v) to (vi), etc., can be measured by X-ray diffraction (XRD) / Rietveld method, etc. The content of calcium oxide (CaO) or calcium hydroxide (Ca(OH)2) in components (i) to (ii) and components (v) to (vi), etc., can be measured by X-ray diffraction (XRD) / Rietveld method or in accordance with "JCAS I-01-1997 (Method for the Quantitative Determination of Free Calcium Oxide)".

[0028] Furthermore, when magnesium is included as an alkaline earth metal, the magnesium content in the powdered cement is preferably 1.0 to 10% by mass, more preferably 2.5 to 8.0% by mass, and particularly preferably 4.0 to 6.0% by mass, in terms of oxide. If the above content is 1.0% by mass or higher, the strength development of the cement composition is further improved. If the above content exceeds 10% by mass, the initial strength development of the cement composition (for example, at 1 day of age) may decrease. Furthermore, when calcium is included as an alkaline earth metal, the calcium content in the powdered cement is preferably 0.8 to 10% by mass, more preferably 1.0 to 4.0% by mass, even more preferably 1.2 to 3.0% by mass, and particularly preferably 1.5 to 2.0% by mass, in terms of oxide. If the above content is 0.8% by mass or higher, the strength development of the cement composition is further improved. If the above content exceeds 10.0% by mass, the initial strength development of the cement composition (for example, at 1 day of age) may decrease.

[0029] [(v) Ingredient: Gypsum] The SO3 content in the powdered cement composition is preferably 6.0% by mass or less, more preferably 0.5 to 5.0% by mass, even more preferably 1.0 to 4.5% by mass, and particularly preferably 1.5 to 4.0% by mass. If the above content is 6.0% by mass or less, the strength development of the cement composition can be further improved. (i) When Portland cement clinker is used as component (i), or when the SO3 content of component (ii) is low, if the SO3 content in the powdered cement mixture does not fall within the desired numerical range, gypsum may be used as a material for the powdered cement composition in addition to components (i) to (ii) and (iv) for the purpose of adjusting the SO3 content in the powdered cement mixture to fall within the aforementioned numerical range. Examples of types of gypsum are not particularly limited and include, for example, natural dihydrate gypsum, flue gas desulfurization gypsum, phosphate gypsum, titanium gypsum, hydrofluoric acid gypsum, etc. These may be used individually or in combination of two or more types. Examples of gypsum forms (whether hydrated or not) include dihydrate gypsum, hemihydrate gypsum, and anhydrous gypsum. These may consist of only one form or may include two or more forms. Furthermore, if the powdered cement-containing material is a crushed Portland cement clinker, it preferably contains gypsum in addition to components (i) to (ii) and (iv).

[0030] [(vi) Ingredients: Other] The powdered cement-containing material may, as necessary, contain other materials in addition to the above-mentioned components (components (i) to (ii) and (iv)), within limits that do not hinder the objectives of the present invention. Other materials that may be added as necessary include various admixtures such as fly ash, silica fume, and blast furnace slag powder, as well as various powdered admixtures. The powdered cement-containing material may also contain alkali metals. The content of other materials in the powdered cement-containing material is preferably 30% by mass or less, and more preferably 20% by mass or less, from the viewpoint of the strength development of the powdered cement-containing material.

[0031] [(B) Component] Cement composition A contains (iii) amine as component (B). [(iii) Component: Amine] Examples of amines include alkanolamines, alkylamines, polyamines, and chain amines such as hydroxylamines, as well as water-soluble amines such as cyclic amines. These may be used individually or in combination of two or more types. In particular, chain-like amines are preferred, and alkanolamines are more preferred, from the viewpoint of improving strength development and increasing the amount of carbon dioxide fixed. Here, an alkanolamine is an amine that has an amino group and a hydroxyl group in its molecule. Examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, methyldiethanolamine, 2-amino-2-methyl-1-propanol, methyldiisopropanolamine, diethanolisopropanolamine, diisopropanolethanolamine, tetrahydroxyethylethylenediamine, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, tris(2-hydroxybutyl)amine, diglycolamine, etc. Among these, monoethanolamine, diethanolamine, and triisopropanolamine are preferred from the viewpoint of ease of availability and improved strength development. These may be used individually or in combination of two or more.

[0032] Alkanolamines in which a portion of the alkanolamine is bonded to the polymer may also be used. Furthermore, used alkanolamine obtained from a carbon dioxide recovery device may be used as the alkanolamine. In amine-based carbon dioxide recovery devices used to recover carbon dioxide from exhaust gases of factories and the like, the liquid containing degraded alkanolamine is usually discarded. However, in the present invention, the above-mentioned waste liquid can be effectively utilized. Alkanolamines are known as grinding aids and may also be used for that purpose.

[0033] The amount of (B) amine per 100 parts by mass of the (A) powdered cement-containing material described above is preferably 0.001 to 5.0 parts by mass, more preferably 0.005 to 4.0 parts by mass, even more preferably 0.02 to 2.0 parts by mass, even more preferably 0.05 to 1.8 parts by mass, even more preferably 0.1 to 1.6 parts by mass, even more preferably 0.5 to 1.4 parts by mass, and particularly preferably 0.8 to 1.2 parts by mass. If the above amount is 0.001 parts by mass or more, the amount of carbon dioxide fixed can be increased, and the strength development can be further improved. If the above amount is 5.0 parts by mass or less, the fluidity of the hydraulic composition before hardening can be prevented from deteriorating. Furthermore, cement composition A is preferably in powder form from the viewpoint of ease of transportation and manufacture of hydraulic compositions.

[0034] [Method for manufacturing cement composition A] The method for producing cement composition A is not particularly limited, and examples include a method of preparing a cement composition by mixing the materials such as the components (i) to (vi) described above. The order in which the materials are mixed is not particularly limited. For example, (a-1) a method of simultaneously mixing pulverized Portland cement or Portland cement clinker, pulverized calcined material containing C2S and C2AS, and amine; (a-2) a method of simultaneously pulverizing and mixing Portland cement or Portland cement clinker and calcined material containing C2S and C2AS, and then mixing the resulting mixture with amine; (a-3) a method of simultaneously pulverizing and mixing Portland cement or Portland cement clinker, calcined material containing C2S and C2AS, and amine. In particular, in the method of simultaneously grinding and mixing Portland cement or Portland cement clinker, a calcined product containing C2S and C2AS, and an amine, the amine also has the effect of a grinding aid. If the cement composition further contains materials such as alkaline earth metals, these materials are usually mixed simultaneously with Portland cement or Portland cement clinker, and fired products containing C2S and C2AS.

[0035] Furthermore, in a method for producing a hydraulic composition (described later) by kneading (mixing) a powdered cement-containing material obtained by pre-mixing components (i) to (ii), component (iii), water, and aggregate, it is preferable that component (iii) is pre-mixed with water to form an aqueous solution. In particular, when used alkanolamine (waste liquid containing alkanolamine) obtained from a carbon dioxide recovery device is used as component (iii), it is preferable to pre-mix it with water in the above method. The proportions of each material are determined so that the content of each material in the cement composition falls within the target numerical range. For example, the amount of alkaline earth metals is determined in advance by measuring the content of alkaline earth metals contained in each material, and then the content (in oxide terms) of alkaline earth metals in the cement composition (however, the only alkaline earth metals other than those contained in the above-mentioned alkaline earth metals are magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide) is determined so that it falls within the target numerical range.

[0036] [Cement Composition B] Other examples of the cement composition of the present invention include a cement composition (hereinafter also referred to as "cement composition B") comprising (i) crushed Portland cement or Portland cement clinker, (ii) crushed calcined product containing 2CaO·SiO2 and 2CaO·Al2O3·SiO2 that satisfies the conditions of (1) to (2) described above, and (iv) alkaline earth metal-containing material, wherein the content of alkaline earth metals in the cement composition (however, the alkaline earth metals other than the alkaline earth metals contained in the alkaline earth metal-containing material (in other words, the alkaline earth metals contained in materials other than the alkaline earth metal-containing material in the cement composition) shall be limited to magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide) in terms of oxides, which shall be 0.1 to 10% by mass. Furthermore, cement composition B does not contain the above-mentioned component (iii).

[0037] In cement composition B, (i) crushed Portland cement or Portland cement clinker, (ii) crushed calcined product containing 2CaO·SiO2 and 2CaO·Al2O3·SiO2 that satisfies the above-mentioned conditions (1) to (2), and (iv) alkaline earth metal-containing material can be the same as components (i), (ii), and (iv) used in cement composition A. The content of Portland cement or crushed Portland cement clinker in cement composition B is preferably 10 to 60% by mass, more preferably 15 to 50% by mass, and particularly preferably 20 to 40% by mass. If the above content is 10% by mass or more, the strength of the hardened body can be increased. If the above content is 60% by mass or less, (ii) the content of crushed material in the fired product becomes larger, and thus the reduction of carbon dioxide emissions mentioned above can be further realized.

[0038] In cement composition B, the amount of crushed calcined material per 100 parts by mass of crushed Portland cement or crushed Portland cement clinker is preferably 30 to 500 parts by mass, more preferably 65 to 450 parts by mass, even more preferably 100 to 400 parts by mass, even more preferably 150 to 350 parts by mass, and particularly preferably 200 to 320 parts by mass. If the above amount is 65 parts by mass or more, the amount of carbon dioxide absorbed by the hydraulic composition in the initial age will be greater. If the above amount is 500 parts by mass or less, the decrease in the strength development of the cement composition due to the relatively small amount of crushed Portland cement or crushed Portland cement clinker will be less likely to occur.

[0039] Furthermore, the content of crushed calcined material in cement composition B is preferably 10 to 90% by mass, more preferably 30 to 85% by mass, even more preferably 40 to 80% by mass, even more preferably 50 to 80% by mass, and particularly preferably 60 to 80% by mass. If the above content is 10% by mass or more, the amount of carbon dioxide absorbed by the hydraulic composition in the initial age will be greater. If the above amount is 90% by mass or less, the decrease in the strength development of the cement composition due to the relatively small amount of Portland cement or crushed Portland cement clinker will be less likely to occur. The ratio of the total amount of component (i) and component (ii) in cement composition B is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more, from the viewpoint of improving the strength development of the cement composition and increasing the amount of carbon dioxide absorbed.

[0040] The content of alkaline earth metals in cement composition B (however, alkaline earth metals other than those contained in the alkaline earth metal-containing material (in other words, alkaline earth metals contained in materials other than the alkaline earth metal-containing material in cement composition B) shall be limited to magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide) is 0.1 to 10% by mass, more preferably 0.2 to 8% by mass, and particularly preferably 0.5 to 6% by mass, in terms of oxides. If the above content is less than 0.1% by mass, the strength development of the cement composition will decrease. If the above content exceeds 10% by mass, the initial strength development of the cement composition (for example, at 1 day of age) may decrease. Furthermore, if cement composition B contains multiple alkaline earth metals (however, the only alkaline earth metals other than those contained in the alkaline earth metal-containing material are magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide), the above content rate is the total content rate.

[0041] The components (i) to (ii) above, component (v) (described later), and component (vi) (described later) may include periclase (MgO), magnesium hydroxide (Mg(OH)2), calcium oxide (CaO; especially free calcium oxide), calcium hydroxide (Ca(OH)2), etc. The alkaline earth metal content mentioned above includes these alkaline earth metals in addition to the alkaline earth metals contained in the alkaline earth metal-containing material. Furthermore, alkaline earth metals (e.g., calcium) dissolved in silicate minerals (e.g., belite, alite), aluminate phase, and ferrite phase, as well as alkaline earth metals other than magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide, such as gypsum (CaSO4) and calcium carbonate, contained in components (i) to (ii) and components (v) to (vi), are unlikely to affect the effects of the present invention, or they are present in such small amounts that they hardly affect the effects of the present invention.

[0042] When cement composition B contains magnesium as an alkaline earth metal, the magnesium content in cement composition B is preferably 1.0 to 10% by mass, more preferably 2.5 to 8% by mass, and particularly preferably 4.0 to 6% by mass, in terms of oxide. If the above content is 1.0% by mass or higher, the strength development of the cement composition is further improved. If the above content exceeds 10% by mass, the initial strength development of the cement composition (e.g., at 1 day of age) may decrease. Furthermore, if cement composition B contains calcium as an alkaline earth metal, the calcium content in cement composition B is preferably 0.8 to 10% by mass, more preferably 1.0 to 4.0% by mass, even more preferably 1.2 to 3.0% by mass, and particularly preferably 1.5 to 2.0% by mass, in terms of oxide. If the above content is 0.8% by mass or higher, the strength development of the cement composition is further improved. If the above content exceeds 10.0% by mass, the initial strength development of the cement composition (for example, at 1 day of age) may decrease.

[0043] The SO3 content in cement composition B is preferably 6.0% by mass or less, more preferably 0.5 to 5.0% by mass, even more preferably 1.0 to 4.5% by mass, and particularly preferably 1.5 to 4.0% by mass. If the above content is 6.0% by mass or less, the strength development of the cement composition can be further improved. (i) When Portland cement clinker is used as component (i), or when the SO3 content of component (ii) is low, if the SO3 content in cement composition B does not fall within the desired numerical range, gypsum can be used as component (v) in addition to components (i) to (ii) and (iv) as a material for cement composition B, in order to adjust the SO3 content in cement composition B to fall within the above-mentioned numerical range. In cement composition B, (v) gypsum can be the same as component (v) used in cement composition A. If component (i) of cement composition B is crushed Portland cement clinker, it is preferable to include gypsum in addition to components (i) to (ii) and (iv).

[0044] Cement composition B may, if necessary, contain other materials (component (vi)) in addition to the above-mentioned components (components (i), (ii), (iv), and (v)), as long as they do not hinder the objectives of the present invention. Other materials that may be added as needed include various admixtures such as fly ash, silica fume, and blast furnace slag powder, as well as various powdered admixtures. In addition, cement composition B may contain alkali metals in addition to alkaline earth metals. The content of other materials in cement composition B is preferably 30% by mass or less, and more preferably 20% by mass or less, from the viewpoint of the strength development of the cement composition. Furthermore, cement composition B is preferably in powder form from the viewpoint of ease of transport and manufacture of hydraulic compositions.

[0045] [Method for producing cement composition B] The method for producing cement composition B is not particularly limited, and examples include a method of preparing a cement composition by mixing the materials such as the components (i) to (ii) and (iv) to (vi) described above. The order in which the materials are mixed is not particularly limited. For example, (i) a method of simultaneously mixing crushed Portland cement or Portland cement clinker, crushed calcined material containing C2S and C2AS, and powdered alkaline earth metal-containing material; (ii) a method of simultaneously crushing and mixing Portland cement or Portland cement clinker, calcined material containing C2S and C2AS, and lump-shaped alkaline earth metal-containing material; (iii) a method of simultaneously crushing and mixing Portland cement or Portland cement clinker and calcined material containing C2S and C2AS, and then mixing the resulting mixture with powdered alkaline earth metal-containing material. Furthermore, when crushing Portland cement or Portland cement clinker and a calcined product containing C2S and C2AS, a crushing aid may be used. The proportions of each material are determined so that the content of each material in the cement composition falls within the target numerical range. For example, the amount of alkaline earth metals is determined in advance by measuring the content of alkaline earth metals contained in each material, and then the content (in oxide terms) of alkaline earth metals in the cement composition (however, the only alkaline earth metals other than those contained in the above-mentioned alkaline earth metals are magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide) is determined so that it falls within the target numerical range.

[0046] [Hydraulic composition] The cement composition A or B described above can be hardened by adding water. An example of the hydraulic composition of the present invention is one which contains the above-mentioned cement composition A, water, and aggregate, with the amount of water being 25 to 70 parts by mass per 100 parts by mass of powdered cement-containing material (hereinafter also referred to as "hydraulic composition A"). Another example of the hydraulic composition of the present invention is one comprising the above-mentioned cement composition B, water, and aggregate, wherein the amount of water is 25 to 70 parts by mass per 100 parts by mass of cement composition (hereinafter also referred to as "hydraulic composition B"). In this specification, "hydraulic composition" includes both the fluid form before curing and the form after curing.

[0047] The type of water used is not particularly limited and includes tap water, and recycled water as defined in "JIS A 5308:2019 (Ready-Mixed Concrete)". In hydraulic composition A, the amount of water per 100 parts by mass of powdered cement is 25 to 70 parts by mass, preferably 30 to 65 parts by mass, more preferably 40 to 60 parts by mass, and particularly preferably 45 to 55 parts by mass. If the above amount is less than 25 parts by mass, the fluidity of the hydraulic composition before hardening decreases. If the above amount exceeds 70 parts by mass, the strength of the hardened body of the hydraulic composition decreases. In hydraulic composition B, the amount of water per 100 parts by mass of cement composition B is 25 to 70 parts by mass, preferably 30 to 65 parts by mass, more preferably 40 to 60 parts by mass, and particularly preferably 45 to 55 parts by mass. If the above amount is less than 25 parts by mass, the fluidity of the hydraulic composition before hardening decreases. If the above amount exceeds 70 parts by mass, the strength of the hardened body of the hydraulic composition decreases.

[0048] The aggregate can consist of fine aggregate alone, or a combination of fine aggregate and coarse aggregate. Natural aggregate, artificial aggregate, or recycled aggregate can also be used. The fine aggregate is not particularly limited and includes, for example, river sand, mountain sand, land sand, sea sand, crushed sand, silica sand, limestone fine aggregate, slag fine aggregate, lightweight fine aggregate, clinker fine aggregate, glass aggregate, and CCU fine aggregate (fine aggregate with carbon dioxide fixed from one or more types selected from recycled aggregate, waste concrete, blast furnace slag, and steelmaking slag). These may be used individually or in combination of two or more types.

[0049] The coarse aggregate is not particularly limited and includes, for example, river gravel, mountain gravel, land gravel, sea gravel, crushed stone, limestone coarse aggregate, slag coarse aggregate, lightweight coarse aggregate, clinker coarse aggregate, glass aggregate, and CCU coarse aggregate (coarse aggregate with carbon dioxide fixed from one or more types selected from recycled aggregate, waste concrete, blast furnace slag, and steelmaking slag). These may be used individually or in combination of two or more types. When a hydraulic composition contains coarse aggregate, the fine aggregate ratio (the volume ratio of fine aggregate to (fine aggregate + coarse aggregate) expressed as a percentage) is preferably 5-70%, more preferably 10-60%, and particularly preferably 20-50%. If the fine aggregate ratio is within the above range, the workability and ease of molding of the hydraulic composition before hardening will be improved. The aggregate content in hydraulic composition A (total amount if fine aggregate and coarse aggregate are used in combination) is preferably 200 to 750 parts by mass, more preferably 300 to 650 parts by mass, per 100 parts by mass of powdered cement-containing material. The aggregate content in hydraulic composition B (the total amount if fine aggregate and coarse aggregate are used in combination) is preferably 200 to 750 parts by mass, more preferably 300 to 650 parts by mass, per 100 parts by mass of cement composition B. If the above content is within the above numerical range, the strength of the hardened body of the hydraulic composition will be greater, and the shrinkage rate of the hardened body will be smaller.

[0050] The hydraulic composition may optionally contain various admixtures such as cement dispersants (water-reducing agents, AE water-reducing agents, high-performance AE water-reducing agents), AE agents, defoaming agents, shrinkage-reducing agents, organic fibers, glass fibers, etc., as long as they do not hinder the objectives of the present invention.

[0051] When the hydraulic composition of the present invention is a carbonated hardened body (particularly a hardened body obtained by carbonation curing), the strength of the hydraulic composition can be increased. Carbonated hardened materials can be obtained, for example, by performing carbonation curing on a hydraulic composition. Carbonation curing fixes carbon dioxide in the hydraulic composition, densifying its structure and thereby increasing its strength. The method of carbonation curing is not particularly limited, but examples include a method of carbonation curing by exposing the hydraulic composition to carbon dioxide, or a method of blowing carbon dioxide into the hydraulic composition during the mixing of the hydraulic composition (in this case, a larger amount of carbon dioxide can be absorbed). Furthermore, the carbonation of hydraulic compositions (other than carbonation curing) includes methods in which carbonation occurs naturally over a long period of time by absorbing carbon dioxide from the air in the form of concrete products, concrete structures, or concrete pavements. The amount of carbon dioxide fixed per ton of cement composition is preferably 80 to 400 kg / ton, more preferably 100 to 350 kg / ton, even more preferably 150 to 330 kg / ton, even more preferably 200 to 315 kg / ton, and particularly preferably 250 to 300 kg / ton. If the fixed amount is 80 kg / ton or more, the total amount of carbon dioxide emitted can be further reduced. If the fixed amount is 400 kg / ton or less, productivity can be further improved.

[0052] [Method for producing a hydraulic composition] An example of a method for producing a hardened body of a hydraulic composition obtained by carbonation curing is a method that includes a mixture preparation step of preparing a mixture using each material constituting the cement composition, water, and aggregate; a casting step of casting the mixture into a formwork; a demolding step of demolding the hardened mixture from the formwork after the mixture has hardened in the formwork; and a carbonation curing step of carbonating the hardened mixture demolded from the formwork to obtain a carbonized hardened body. The following explains each step in detail.

[0053] [Preparation process for kneaded products] This process involves preparing a mixture of the materials constituting the cement composition, water, and aggregate. In the hydraulic composition A, there are no particular limitations on the method for preparing a mixture using each of the materials constituting the cement composition A, water, and aggregate. Examples include (a-1) a method of simultaneously mixing a pre-prepared cement composition A, water, and aggregate; and (a-2) a method of simultaneously mixing a powdered cement-containing material (A) obtained by pre-mixing components (i) to (ii) constituting component (A), component (B), water, and aggregate. In the hydraulic composition B, the method for preparing a mixture using each of the materials constituting the cement composition B, water, and aggregate is not particularly limited, and examples include (b-1) a method of simultaneously mixing a pre-prepared cement composition B, water, and aggregate, and (b-2) a method of simultaneously mixing a pre-mixed mixture of components (i) to (ii), component (iv), water, and aggregate. The method of mixing each ingredient is not particularly limited. Furthermore, the equipment used for mixing is also not particularly limited; for example, conventional mixers such as omni mixers, pan mixers, twin-shaft mixers, and tilting-drum mixers can be used.

[0054] [Concrete pouring process] This process involves pouring the mixture obtained in the previous process into a mold. The concrete placement method is not particularly limited, and conventional methods such as pour molding can be used. The curing method after pouring the mixed material into the formwork until demolding is not particularly limited, and general curing methods such as air curing, humid air curing, underwater curing, sealed curing, and steam curing can be employed. [Demolding process] This process involves demolding the hardened hydraulic composition, which is formed from the hardened mixture inside the mold, from the mold after the mixture has hardened.

[0055] [Carbonation curing process] This process involves carbonizing the hardened hydraulic composition that has been demolded from the mold, in order to obtain a carbonated hardened body obtained by carbonizing the hardened hydraulic composition. Furthermore, from the viewpoint of maximizing carbon dioxide absorption during carbonation curing, the concentration of carbon dioxide gas is preferably 1 volume% or more, more preferably 10 volume% or more, even more preferably 50 volume% or more, and particularly preferably 60 volume% or more. Also, from the viewpoint of reducing costs related to curing equipment, etc., the concentration of carbon dioxide gas is preferably 95 volume% or less, more preferably 85 volume% or less, and even more preferably 80 volume% or less. The temperature for carbonation curing is preferably 5 to 100°C, more preferably 10 to 90°C, even more preferably 15 to 80°C, even more preferably 20 to 75°C, even more preferably 25 to 70°C, even more preferably 30 to 65°C, even more preferably 30 to 50°C, and particularly preferably 30 to 40°C. If the temperature is 5°C or higher, the efficiency of carbonation is further improved and the strength of the cured product is increased. If the temperature is 100°C or lower, the energy cost of carbonation curing can be further reduced. Furthermore, the relative humidity during carbonation curing is preferably 20-90%, more preferably 30-80%, and particularly preferably 40-70%. If the relative humidity is 20% or higher, the efficiency of carbonation is further improved, and the strength of the cured material is increased. If the relative humidity is 90% or lower, the costs associated with curing equipment can be further reduced. [Examples]

[0056] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. [A.(ii) Manufacturing of calcined products] Using sewage sludge, construction-generated soil, limestone, and clay as raw materials, the raw materials were mixed so as to be within the target chemical composition range including the chemical composition (measured values in the examples) shown in Table 1, and after preparing the raw materials for firing, the raw materials for firing were fired at 1,370 °C using a rotary kiln to obtain a fired product. In addition to heavy oil, waste oil and waste plastic were used as fuels during firing. Next, after pulverizing the fired product, for the obtained pulverized product, a powder X-ray diffraction (XRD) pattern of the pulverized product was acquired using an X-ray diffractometer (manufactured by Bruker Japan, trade name "D8 ADVANCE A-25 type"). The measurement conditions for powder X-ray diffraction were: target: CuKα, tube voltage condition: 40 kV - 40 mA, scanning range: 2θ = 5 to 65°, step width: 0.023° / step, and measurement time: 0.13 seconds / step. When the obtained powder XRD pattern was qualitatively analyzed using analysis software (manufactured by Bruker Japan, trade name "DIFFRAC.EVA"), peaks of C2S (β-C2S), C2AS, C3A, and CA were observed. On the other hand, no peak of MgO (periclase) was observed.

[0057] Using analysis software (manufactured by Bruker Japan, trade name "DIFFRAC.TOPAS ver.6"), by fitting the theoretical profiles of each mineral of C2S (β-C2S), C2AS, C3A, and CA to the measured profiles obtained from the results of powder XRD by the Rietveld method, the mineral composition of the pulverized product was measured. The results are shown in Table 2. In accordance with "JCAS I-01-1997 (Quantitative Method for Free Calcium Oxide)", when the content rate of f.CaO in the fired product was measured, it was 0.3 mass%. Mg(OH)2 and Ca(OH)2 were not contained in the fired product. The Blaine specific surface area of the pulverized fired product was 3,310 cm 2 / g.

[0058]

Table 1

[0059] [Table 2]

[0060] [B. Preparation of hydraulic composition] [Materials used] (1) Cement: Ordinary Portland cement (Brain specific surface area: 3,290 cm²) 2 / g); Manufactured by Taiheiyo Cement Corporation; possessing the chemical composition shown in Table 3 and the mineral composition shown in Table 4; the chemical composition of the cement was measured in accordance with "JIS R 5204:2019 (X-ray fluorescence analysis method for cement)". No peak of periclase (MgO) was observed in X-ray diffraction. The mineral composition of the cement was measured in the same manner as the crushed calcined material described above, except that the mineral settings in the analysis software were changed to the types of minerals shown in Table 4. The f.CaO content of the cement, measured in accordance with "JCAS I-01-1997 (Method for determination of free calcium oxide)", was 0.2 mass%. The cement did not contain Mg(OH)2 or Ca(OH)2. (2) Firing products: as described above (3) Gypsum: Excluded dihydrate gypsum (4) Amine A: Monoethanolamine (2-aminoethanol) (5) Amine B: Diethanolamine (2,2'-iminodiethanol) (6) Amine C: Triisopropanolamine aqueous solution (Triisopropanolamine content: 85% by mass) (7) Amine D: 2-amino-2-methyl-1-propanol (8) MgO: Periclase (industrial reagent, MgO content: 95.0% by mass or more) (9) MgSO4·7H2O: Reagent (10) CaO: Hard calcined quicklime (industrial reagent, CaO content: 93.0% by mass or more) (11) Ready-mix concrete sludge: Ready-mix concrete sludge is dried at 105°C as a pretreatment and then crushed, with a BET specific surface area of ​​14.71 m². 2 / g, average particle size (frequency basis) 46.9 μm, 50% volume cumulative particle size (D50) 20.4 μm, chemical composition as shown in Table 5 (measured in accordance with "JIS R 5204:2019 (X-ray fluorescence analysis method for cement)"), calcium hydroxide content 15.8% by mass. (12) Fine aggregate: Cement Association standard sand

[0061] [Table 3]

[0062] [Table 4]

[0063] [Table 5]

[0064] [Reference examples 1~3] The calcined material and excreted dihydrate gypsum were mixed and ground in a mass ratio of 95.67:4.33 to obtain a mixture of the ground calcined material and excreted dihydrate gypsum. The above mixture and ordinary Portland cement were mixed in a mass ratio of 75:25 (mixture:ordinary Portland cement) to obtain a powdered cement-containing material. The chemical composition (measured value) of the powdered cement-containing material is shown in Table 6, and the mineral composition (calculated value) is shown in Table 7. The chemical composition of the powdered cement-containing material was measured in accordance with "JIS R 5204:2019 (X-ray fluorescence analysis method for cement)". The mineral composition was measured in the same manner as the crushed calcined material. The Blaine specific surface area of ​​the powdered cement-containing material was 3,300 cm². 2 It was / g. The obtained powdered cement-containing material, the types of amines shown in Table 8, fine aggregate, and water were used in the amounts shown in Table 8 (where "Water / Powdered Cement-Containing Material" in Table 8 indicates the mass ratio of water to powdered cement-containing material) to prepare test specimens in accordance with "JIS R 5201:2015 (Physical Test Methods for Cement)". After 1 day, the specimens were demolded and subjected to carbonation curing in a curing tank at a temperature of 65°C, relative humidity of 60%, and carbon dioxide concentration of 80% by volume. While carbonation curing was being performed, the compressive strength and flexural strength of the test specimens (hardened bodies of hydraulic compositions) were measured at 7 days of age (excluding the 1 day from the preparation of the test specimens until demolding) in accordance with "JIS R 5201:2015 (Physical Test Methods for Cement)".

[0065] Specimens were prepared in the same manner as described above for measuring compressive and flexural strength. After demolding, carbonation curing was performed in a curing tank at a temperature of 65°C, relative humidity of 60%, and carbon dioxide concentration of 20% by volume. After crushing the specimens at 3, 7, and 14 days of age, the amount of carbon in the specimens was measured using a carbon-sulfur analyzer, and the amount of carbon dioxide (A) in the specimens was determined by converting the obtained measurement values ​​to CO2. Next, based on the amount of carbon contained in each specimen (hardened body of the hydraulic composition) measured with the carbon-sulfur analyzer and the composition of the hydraulic composition, the amount of carbon dioxide (B) contained in the specimens before carbonation curing was determined, and the amount of carbon dioxide immobilized in the specimens was calculated from the difference (AB) between the amount of carbon dioxide before and after carbonation curing. The amount of carbon dioxide fixed (kg / ton) was calculated by dividing the amount of carbon dioxide fixed in the test specimen by the amount of cement used in the specimen. Furthermore, after performing carbonation curing for up to 3 years, the specimens were removed from the curing tank and cured for an additional 4 days in a constant temperature and humidity chamber at 20°C and 60% relative humidity (indicated as "3 days + 4 days" in Table 8). The amount of carbon dioxide fixed in these specimens was measured in the same manner.

[0066] [Comparative Example 1] The compressive strength and flexural strength of the hydraulic composition at 7 days of age were measured in the same manner as in Reference Example 1, except that amines were not used. The results are shown in Table 9.

[0067] [Table 6]

[0068] [Table 7]

[0069] [Table 8]

[0070] [Table 9]

[0071] From Table 9, the compressive strengths of Reference Examples 1-3 are (55.9-68.2 N / mm²). 2 This is the compressive strength of Comparative Example 1 (55.6 N / mm²). 2 It can be seen that it is larger than ). Also, the bending strength (10.4~12.2 N / mm²) of the material at 7 days of age in Reference Examples 1-3. 2 ) is the bending strength (10.4 N / mm²) of Comparative Example 1 at 7 days of age. 2 It can be seen that it is equal to or better than ). Furthermore, it can be seen that the carbon dioxide fixation amounts in Reference Examples 1-3 (3 days old: 232-236 kg / ton, 7 days old: 237-240 kg / ton, 14 days old: 239-247 kg / ton, 3+4 days old: 236-238 kg / ton) are greater than the carbon dioxide fixation amounts in Comparative Example 1 (3 days old: 227 kg / ton, 7 days old: 231 kg / ton, 14 days old: 234 kg / ton, 3+4 days old: 233 g / ton).

[0072] [Examples 1-3, Reference Examples 4-5] A cement composition was obtained by mixing the powdered cement-containing material prepared in Reference Example 1 with the types of alkaline earth metal-containing materials shown in Table 10 in the proportions shown in Table 10. In Table 10, "Alkaline earth metal content" refers to the content of alkaline earth metals in the cement composition (in oxide terms). Also in Table 10, "derived from f·CaO" refers to the f·CaO contained in the cement composition. The obtained cement composition (shown as "Composition" in Table 10), fine aggregate, and water were used in the amounts shown in Table 10 (in Table 10, "Water / Composition" indicates the mass ratio of water to the cement composition) to prepare test specimens in accordance with "JIS R 5201:2015 (Physical Test Methods for Cement)". After demolding, carbonation curing was performed in a curing tank at a temperature of 30°C, relative humidity of 60%, and carbon dioxide concentration of 80% by volume. While performing carbonation curing, the compressive and flexural strengths of the test specimens (hardened hydraulic compositions) were measured at 3 and 7 days of age in accordance with "JIS R 5201:2015 (Physical Testing Methods for Cement)". Furthermore, for specimens subjected to carbonation curing at 1, 3, and 7 days of age, similar to the measurement of bending strength, a 1% phenolphthalein ethanol solution was sprayed onto the fracture surface of the specimen after the bending test. The carbonation depth (the area that changed color due to the spraying of the 1% phenolphthalein ethanol solution) was measured from the sides (4 sides) of the specimen using calipers, and the average value was taken as the carbonation depth (carbonation depth). In Table 11, "20.0 mm" indicates complete carbonation.

[0073] [Comparative Example 2] The compressive and flexural strengths of the hydraulic composition were measured at 3 and 7 days of age, in the same manner as in Example 1, except that alkaline earth metal-containing materials were not used. The results are shown in Table 11.

[0074] [Table 10]

[0075] [Table 11]

[0076] Table 11 shows the compressive strength (age 3 days: 48.9-58.0 N / mm²) of Examples 1-3 and Reference Examples 4-5. 2 , Material age 7 days: 58.3~72.7N / mm 2 ) is the compressive strength of Comparative Example 2 (age 3 days: 45.1 N / mm²). 2 , material age 7 days: 52.8N / mm 2 It can be seen that it is larger than ). Furthermore, the bending strength (10.1-12.5 N / mm²) at 3 days of age for Examples 1-3 and Reference Example 5 is also shown. 2 ) is the bending strength (9.8 N / mm²) of Comparative Example 2 at 3 days of age. 2 It can be seen that it is larger than ). Furthermore, the bending strength (12.1-14.8 N / mm²) at 7 days of age for Examples 1-3 and Reference Examples 4-5 is also measured. 2 ) is the bending strength (11.7 N / mm²) of Comparative Example 2 at 7 days of age. 2 It can be seen that it is larger than ). Furthermore, the neutralization depths in Examples 1-3 and Reference Examples 4-5 indicate that the specimens were carbonated even internally after 3 days of age.

[0077] [Reference examples 6-10] A cement composition was obtained by mixing a mixture of the crushed calcined material and exfoliated dihydrate gypsum prepared in Reference Example 1 with a mixture of ordinary Portland cement (corresponding to the powdered cement-containing material in Reference Example 1: indicated as "powdered raw material" in Table 12) and the types and amounts of amines shown in Table 12. The obtained cement composition (referred to as "Composition" in Table 12), fine aggregate, and water were used in the amounts shown in Table 12 (where "Water / Composition" in Table 12 indicates the mass ratio of water to the cement composition) to prepare test specimens in accordance with "JIS R 5201:2015 (Physical Test Methods for Cement)". After demolding, carbonation curing was performed in a curing tank at a temperature of 30°C, relative humidity of 60%, and carbon dioxide concentration of 80% by volume. While carbonation curing was being performed, the compressive strength of the test specimens (hardened bodies of the hydraulic composition) at 7 days of age was measured in accordance with "JIS R 5201:2015 (Physical Test Methods for Cement)".

[0078] The specimens were prepared in the same manner as the compressive strength measurement described above, and after demolding, Temperature 30℃ Carbonation curing was performed in a curing tank with a relative humidity of 60% and a carbon dioxide concentration of 20% by volume. For the specimens at 3 days and 7 days of age, the amount of carbon dioxide fixed (kg / ton) was calculated in the same manner as in Reference Example 1. In Table 13, "―" indicates that measurement was not performed.

[0079] [Example 4] A mixture of the crushed calcined material and exfoliated dihydrate gypsum prepared in Reference Example 1, along with a mixture of ordinary Portland cement, was mixed with the amount of alkaline earth metal-containing material shown in Table 12 to obtain a powdered cement-containing material. The obtained powdered cement-containing material was mixed with the types and amounts of amines shown in Table 12 to obtain a cement composition. In Table 12, "derived from f·CaO" refers to the f·CaO contained in the powdered cement-containing material. Using the obtained cement composition, specimens were prepared in the same manner as in Reference Example 6, and the compressive strength of the specimens at 7 days of age was measured in the same manner as in Reference Example 6. In addition, the bending strength of the specimens was measured at 3 days and 7 days of age, in accordance with "JIS R 5201:2015 (Physical Testing Methods for Cement)". For specimens subjected to carbonation curing at 3 and 7 days of age, in the same manner as for measuring bending strength, the carbonation depth was measured from the sides (4 sides) of the specimens in the same manner as in Example 1, and the average value was taken as the carbonation depth (carbonation depth). In Table 13, "20.0 mm" indicates complete carbonation. The results are shown in Table 13.

[0080] [Table 12]

[0081] [Table 13]

[0082] Tables 9 and 13 show that the amount of carbon dioxide fixed at 7 days of age for Reference Examples 6-10 (292-315 kg / ton) is greater than the amount of carbon dioxide fixed at 7 days of age for Reference Examples 1-3 (carbonation curing performed in a curing tank at a temperature of 65°C, relative humidity of 60%, and carbon dioxide concentration of 20% by volume) (237-240 kg / ton). From Tables 11 and 13, the compressive strength (60.6 to 74.8 N / mm²) at 7 days of age for Reference Examples 6-10 and Example 4 can be seen. 2 ) is the compressive strength (7 days old: 52.8 N / mm²) of Comparative Example 2 (which did not use either amines or alkaline earth metals, and had the same curing conditions as Reference Examples 6-10 and Example 4). 2 It can be seen that it is larger than ). In particular, the compressive strength of Example 4 (using amine and alkaline earth metal-containing material) at 7 days of age (74.8 N / mm²) 2 ) is the largest. Bending strength of Example 4 (age 3 days: 11.8 N / mm 2 , material age 7 days: 16.6N / mm 2 ) is the bending strength of Comparative Example 2 (age 3 days: 9.8 N / mm²). 2 , 11.7 N / mm 2 It can be seen that it is larger than ). From the neutralization depth in Example 4, it can be seen that the specimen was carbonated all the way through to its interior after 7 days of age.

[0083] [Reference Example 11, Example 5] A mixture of crushed calcined material and exfoliated dihydrate gypsum prepared in Reference Example 1 and a mixture of ordinary Portland cement (corresponding to the powdered cement-containing material in Reference Example 1: indicated as "powdered raw material" in Table 14), and the types and proportions shown in Table 14. material The following were mixed to obtain a cement composition. In Example 5, Alkaline earth metal-containing substances and MgSO 4 ·7H 2 O was mixed in. In Table 14, "Alkaline Earth Metal Content" refers to the content of alkaline earth metals in the cement composition (in oxide terms). The obtained cement composition (referred to as "Composition" in Table 14), fine aggregate, and water were used in the amounts shown in Table 14 (where "Water / Composition" in Table 14 indicates the mass ratio of water to the cement composition) to prepare test specimens in accordance with "JIS R 5201:2015 (Physical Test Methods for Cement)". After demolding, carbonation curing was performed in a curing tank at a temperature of 30°C, relative humidity of 60%, and carbon dioxide concentration of 80% by volume. While carbonation curing was being performed, the compressive strength of the test specimens (hardened bodies of the hydraulic composition) at 7 days of age, as well as the flexural strength at 3 days and 7 days of age, were measured in accordance with "JIS R 5201:2015 (Physical Test Methods for Cement)". For specimens subjected to carbonation curing at 3 and 7 days of age, in the same manner as for measuring bending strength, the carbonation depth was measured from the sides (4 sides) of the specimens in the same manner as in Example 1, and the average value was taken as the carbonation depth (carbonation depth). In Table 13, "20.0 mm" indicates complete carbonation. The results are shown in Table 15.

[0084] [Table 14]

[0085] [Table 15]

[0086] From Tables 11 and 15, the compressive strength (53.5~56.9 N / mm²) at 7 days of age for Reference Example 11 and Example 5 can be seen. 2 ) is the compressive strength (7 days old: 52.8 N / mm²) of Comparative Example 2 (which did not use either amines or alkaline earth metals, and had the same curing conditions as Reference Example 11 and Example 5). 2 It can be seen that it is larger than ). Reference Example 11 and Example 5: Bending strength (3 days old: 10.3~11.5 N / mm 2 , material age 7 days: 11.6~13.1N / mm 2 ) is the bending strength of Comparative Example 2 (age 3 days: 9.8 N / mm²). 2 , 11.7 N / mm 2It can be seen that it is equivalent to or greater than ). From the neutralization depths in Reference Example 11 and Example 5, it can be seen that the specimens were carbonated all the way to their interiors.

Claims

1. (A) (i) Portland cement or crushed Portland cement clinker, (ii) 2CaO・SiO ２ and 2CaO·Al ２ O ３ SiO ２ A pulverized product of a calcined product containing the following, and a pulverized product of a calcined product that satisfies the following conditions (1) to (2), (iv) A cement composition containing an alkaline earth metal (however, limited to those other than those described in (i) and (ii) above), The alkaline earth metal contained in the above alkaline earth metal-containing material is magnesium (Mg). The above alkaline earth metal-containing material is at least one selected from the minerals periclase, calcined magnesia, partially hydrated calcined magnesia, calcined dolomite, and partially hydrated calcined dolomite. In the above cement composition, the total content of free calcium oxide and the content of magnesium (Mg) contained in the above alkaline earth metal-containing material, in terms of oxide, is 2.0 to 5.3% by mass. In the above cement composition, the content of magnesium (Mg) in terms of oxides contained in the above alkaline earth metal-containing material is 1.7 to 5.0% by mass. A cement composition characterized in that the content of the crushed (ii) calcined product in the above cement composition is 10 to 90% by mass. (1) The above 2CaO・SiO ２ The above 2CaO・Al per 100 parts by mass ２ O ３ SiO ２ The amount is 10 to 100 parts by mass. (2) The fired product does not contain 3CaO·Al ２ O ３ or contains it in an amount of 15 parts by mass or less with respect to 100 parts by mass of the above 2CaO·SiO ２ ​

2. Furthermore, comprising MgSO4, The cement composition according to claim 1, wherein the total content of magnesium (Mg) and calcium (Ca) in terms of oxides contained in materials other than the alkaline earth metal-containing material in the cement composition (however, the content of magnesium (Mg) and calcium (Ca) in terms of oxides is limited to the content of magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide) is 0.1 to 6.0% by mass.

3. A hydraulic composition comprising the cement composition, water, and aggregate described in claim 1 or 2, A hydraulic composition wherein the amount of water is 25 to 70 parts by mass per 100 parts by mass of the cement composition.

4. Furthermore, (B) contains (iii) amine, The cement composition according to claim 1, wherein the amount of the amine is 0.5 to 2.0 parts by mass relative to 100 parts by mass of the total of (i) and (ii) above.

5. The cement composition according to claim 4, wherein the amine is an alkanolamine.

6. A hydraulic composition comprising the cement composition, water, and aggregate according to claim 4 or 5, A hydraulic composition in which the amount of water is 25 to 70 parts by mass relative to 100 parts by mass of the total of (i) and (ii) above.

7. A method for producing the hydraulic composition described in claim 3, A compound preparation step in which a compound is prepared using the materials constituting the cement composition, the water, and the aggregate, The above-mentioned mixture is poured into the formwork in a pouring process, After the above-mentioned mixture has hardened within the above-mentioned mold, a demolding step is performed to remove the hardened body of the mixture from the above-mentioned mold. A method for producing a hydraulic composition, comprising a carbonation curing step of carbonizing the hardened mixture obtained from the above-mentioned mold to obtain a carbonized hardened body.

8. A method for producing the hydraulic composition described in claim 6, A compound preparation step in which a compound is prepared using the materials constituting the cement composition, the water, and the aggregate, The above-mentioned mixture is poured into the formwork in a pouring process, After the above-mentioned mixture has hardened within the above-mentioned mold, a demolding step is performed to remove the hardened body of the mixture from the above-mentioned mold. A method for producing a hydraulic composition, comprising a carbonation curing step of carbonizing the hardened mixture obtained from the above-mentioned mold to obtain a carbonized hardened body.

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