Carbonation promoter for hydraulic composition and production method for hydraulic composition hardened product

Abstract

To provide a carbonation promoter for a hydraulic composition, the promoter being capable of promoting the carbonation of a hydraulic composition when added to the hydraulic composition.SOLUTION: There is provided a carbonation promoter for a hydraulic composition, the promoter containing 10-100 mass% of an anionic surfactant, the anionic surfactant being a compound containing an organic acid ion having 6-50 hydrophobic groups in the molecule.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a carbonation accelerator for a hydraulic composition and a method for producing a hardened body of a hydraulic composition. More specifically, the present invention relates to a carbonation accelerator for a hydraulic composition capable of accelerating the carbonation of the hydraulic composition by adding it to the hydraulic composition, and a method for producing a hardened body of the hydraulic composition.

Background Art

[0002] In recent years, efforts to achieve a decarbonized society such as carbon neutral or carbon negative have been accelerating worldwide. For example, in Japan, the realization of "carbon neutrality in 2050" was declared in 2020, and in 2021, a target was set to reduce greenhouse gas emissions in fiscal year 2030 by 46% (compared to fiscal year 2013).

[0003] Therefore, for example, even the construction industry is working on reducing carbon dioxide (CO2) emissions.

[0004] Specifically, since concrete uses cement that emits a large amount of carbon dioxide during production, it is a material with a very high carbon dioxide emission. Therefore, in order to reduce carbon dioxide emissions, low-carbon cement and low-carbon concrete that reduce the amount of cement used by using industrial by-products such as blast furnace slag fine powder and fly ash are known.

[0005] In addition, precast concrete obtained by hardening a concrete mixture in which γ-C2S (γ-2CaO·SiO2 (sometimes called "γ belite")) is added to steelmaking slag powder and Portland cement and subjecting the concrete to carbonation curing after demolding is also known (see, for example, Patent Document 1). This precast concrete is a technology in which carbonation accompanying the absorption of carbon dioxide proceeds on the concrete surface, densification occurs in that part, and high durability is achieved.

[0006] Here, in Patent Document 1, carbonation curing is performed to densify concrete and improve its durability. On the other hand, this technology involves the fixation and absorption of carbon dioxide by concrete. That is, in the entire concrete manufacturing process, it can be said that the carbon dioxide emissions are reduced by the amount of carbon dioxide fixed and absorbed by the concrete through carbonation curing. Thus, γ-C2S (γ-2CaO·SiO2) may be used as a technology for reducing, fixing, and absorbing carbon dioxide (CO2).

[0007] Similarly, as one of the efforts towards greenhouse gas reduction, a carbonation accelerator that promotes the carbonation of alkaline earth metal compounds has also been reported (see Patent Document 2).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, there is still room for improvement regarding the carbon dioxide absorption amount and absorption rate. Therefore, the development of a carbonation accelerator that can further increase the amount of carbon dioxide absorbed and immobilized by concrete, improve the carbon dioxide absorption rate, or both is desired. Note that increasing the amount of carbon dioxide absorbed by concrete at a predetermined age means shortening the time until a certain amount of carbon dioxide is absorbed, and as a result, it also means shortening the carbonation curing period (shortening the manufacturing time of concrete products).

[0010] In view of the above circumstances, the present invention aims to provide a carbonation accelerator for hydraulic compositions and a method for manufacturing a hardened body of a hydraulic composition, which can promote the carbonation of the hydraulic composition and reduce the carbon dioxide balance of the hydraulic composition by adding thereto. The carbon dioxide balance is the amount of carbon dioxide calculated by the formula: "the amount of carbon dioxide derived from the raw materials constituting the concrete (i.e., the amount of carbon dioxide generated during the production of the raw materials)" - "the amount of carbon dioxide absorbed and immobilized by carbonation curing or the like". And "reducing the carbon dioxide balance" means increasing the reduction amount of carbon dioxide, that is, reducing the value of the amount of carbon dioxide calculated by the above formula.

Means for Solving the Problems

[0011] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by containing a predetermined anionic surfactant. According to the present invention, the following carbonation accelerator for hydraulic compositions and a method for manufacturing a hardened body of a hydraulic composition are provided.

[0012] [1] A carbonation accelerator for a hydraulic composition, comprising an anionic surfactant in a proportion of 10 to 100% by mass, wherein the anionic surfactant is a compound containing an organic acid ion having a hydrophobic group with 6 to 50 carbon atoms in the molecule.

[0013] [2] The carbonation accelerator for a hydraulic composition according to [1] above, wherein the anionic surfactant is at least one compound selected from the compounds represented by the following general formula (1).

[0014]

Chemical Formula

[0015]

Chemical formula

[0016]

Chemical formula

[0017]

Chemical formula

[0018]

Chemical formula

[0019]

Chemical formula

[0020]

Chemical formula

[0021] [3] The carbonation accelerator for the hydraulic composition according to [1], wherein the anionic surfactant is at least one selected from the compounds represented by the following general formulas (1-1) to (1-5).

[0022]

Chemical formula

[0023]

Chemical formula

[0024]

Chemical formula

[0025]

Chemical formula

[0026]

Chemical formula

[0027] [4] The compound represented by the general formula (1-1) is a compound represented by the following general formula (1-1a), The anionic surfactant is a mixture containing the compound represented by the general formula (1-1a) and at least one selected from the compounds represented by the general formulas (1-2) to (1-5), which is the carbonation accelerator for the hydraulic composition according to the above [3].

[0028]

Chemical formula

[0029] [5] A carbonation curing accelerator for a hydraulic composition, which is added to a hydraulic composition that becomes a hardened body of the hydraulic composition through a carbonation curing process, which is a curing process carried out in an environment with a carbon dioxide volume concentration of 5% or more, as described in any one of [1] to [4] above.

[0030] [6] A carbonation curing accelerator for a hydraulic composition, which is added to a hydraulic composition containing a binder containing 40 to 99% by mass of blast furnace slag fine powder, water, and aggregates, as described in any one of [1] to [4] above.

[0031] [7] A carbonation curing accelerator for a hydraulic composition, wherein the hydraulic composition contains γ-2CaO·SiO2, as described in any one of [1] to [4] above.

[0032] [8] A carbonation curing accelerator for a hydraulic composition, wherein the hydraulic composition contains at least one selected from the following CO2-fixing fine powder and the following CO2-fixing modified recycled fine aggregate, as described in any one of [1] to [4] above. CO2-fixing fine powder: The 50% particle size is 50 μm or less, and it contains modified concrete powder, which is a reaction product of recycled concrete powder and carbon dioxide gas. The modified concrete powder contains calcium carbonate and silicate. However, the content ratio of the CO2-fixing fine powder in the hydraulic composition is in the range of 1 to 100% by mass with respect to 100% by mass of the binder. CO2-fixing modified recycled fine aggregate: The particle size of all particles is 10 mm or less, and 85% or more of them are 5 mm or less. It contains a modified recycled fine aggregate, which is a reaction product of a recycled fine aggregate with a water absorption rate of more than 3.0% and less than or equal to 10% and carbon dioxide gas, either dry or wet. The modified recycled fine aggregate contains calcium carbonate and silicon dioxide. However, the content ratio of the CO2-fixing modified recycled fine aggregate in the hydraulic composition is in the range of 10 to 100% by volume with respect to the total aggregate volume.

[0033] [9] A preparation step of preparing a hydraulic composition containing a carbonation accelerator for a hydraulic composition according to any one of [1] to [4], a binder containing 40 to 99% by mass of fine blast furnace slag powder, and water, A curing step of curing the obtained hydraulic composition to obtain a cured body of the hydraulic composition, A carbonation curing step of curing the obtained cured body of the hydraulic composition in an environment having a carbon dioxide volume concentration of 5% or more to absorb and immobilize carbon dioxide in the cured body of the hydraulic composition, A method for producing a cured body of a hydraulic composition, characterized by comprising:

Advantages of the Invention

[0034] The carbonation accelerator for a hydraulic composition of the present invention has an effect of promoting the carbonation of the hydraulic composition and reducing the carbon dioxide balance of the hydraulic composition by adding it to the hydraulic composition.

[0035] According to the method for producing a cured body of a hydraulic composition of the present invention, since a hydraulic composition containing the carbonation accelerator for a hydraulic composition of the present invention is used, an effect of increasing the amount of carbon dioxide reduced in the production process is achieved.

Modes for Carrying Out the Invention

[0036] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments. Therefore, it should be understood that appropriate changes and improvements can be made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. In the following examples, etc., unless otherwise specified, % means mass% and part means mass part.

[0037] (1) Carbonation accelerator for hydraulic composition: The carbonation accelerator for a hydraulic composition of the present invention contains an anionic surfactant at a ratio of 10 to 100% by mass, and this anionic surfactant is a compound containing an organic acid ion having a hydrophobic group with 6 to 50 carbon atoms in the molecule.

[0038] Such an accelerator for carbonation of a hydraulic composition, when added to the hydraulic composition, can accelerate the carbonation of the hydraulic composition and increase the amount of carbon dioxide absorbed by the hydraulic composition (i.e., the amount of carbon dioxide reduction). That is, the carbon dioxide balance of the hydraulic composition can be reduced. Note that calcium silicate hydrate (C-S-H), calcium hydroxide (CH), etc. are generated by the hydration of cement. In addition, the hydraulic composition contains calcium oxide (CaO), etc. as derived from its raw materials. And by the carbonation (reaction with carbon dioxide) of these compounds, carbon dioxide can be absorbed and immobilized in the hydraulic composition (the hardened body of the hydraulic composition).

[0039] For example, in a thermal power plant or the like, carbon dioxide is emitted into the atmosphere as exhaust gas. Although this carbon dioxide is considered to be one of the causes of global warming, by supplying the carbon dioxide in the exhaust gas to the carbonation curing process, the carbon dioxide can be absorbed by the hydraulic composition, and carbon dioxide reduction can be achieved. Note that the hardened body of the hydraulic composition can not only be used in the carbonation curing process, but also be installed at a predetermined location later to permanently immobilize carbon dioxide in the atmosphere.

[0040] (1-1) Anionic surfactant: The content ratio of the anionic surfactant is 10 to 100% by mass, preferably 15 to 100% by mass, and more preferably 20 to 100% by mass. By setting it within the above range, the carbon dioxide balance of the hydraulic composition can be reduced.

[0041] In addition, the "components other than the anionic surfactant" are also those with a reduced content ratio in the following aspects. First, when the "components other than the anionic surfactant" are other than water, it is possible to avoid the addition amount of the "components other than the anionic surfactant" from becoming too large when adding a carbonation accelerator for the hydraulic composition to the hydraulic composition, and it is possible to reduce the concern that the "components other than the anionic surfactant" may affect various physical properties of the hydraulic composition. Further, when the "component other than the anionic surfactant" is water (that is, in the case of an aqueous solution of an anionic surfactant), by setting the above content ratio, the product stability of the carbonation accelerator for the hydraulic composition is likely to be maintained. That is, if the water ratio is too high, it is likely to cause problems such as spoilage.

[0042] An anionic surfactant is a compound containing an organic acid ion having a hydrophobic group with 6 to 50 carbon atoms in the molecule, and by containing this specific organic acid ion, the amount of carbon dioxide absorbed by the hardened body of the hydraulic composition can be increased.

[0043] When the above-mentioned predetermined anionic surfactant is contained in the carbonation accelerator for the hydraulic composition, the following is inferred. That is, fine bubbles can be uniformly carried in the hydraulic composition containing the carbonation accelerator for the hydraulic composition. Therefore, the mass permeability when the hydraulic composition is hardened is improved, and a good flow path for gas (carbon dioxide) to flow from the outer surface to the central part is formed. And by the formation of this flow path, carbon dioxide is likely to flow into the central part of the hardened body during the carbonation curing of the hardened body of the hydraulic composition, and carbonation is further promoted.

[0044] (1-1-1) Compound represented by general formula (1): The anionic surfactant is not particularly limited as long as it satisfies the above conditions. For example, it is preferably at least one compound selected from the compounds represented by the following general formula (1). That is, it may be one compound corresponding to the compound represented by general formula (1), or there may be two or more compounds corresponding to the compound represented by general formula (1).

[0045] [Chemical formula] (In general formula (1), R 1 is an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, an aryl group having 8 to 20 carbon atoms, a residue obtained by removing carboxylic acid from rosin, or a residue obtained by removing hydrogen from a product obtained by adding 1 to 10 moles in total of an alkylene oxide having 2 to 3 carbon atoms per mole of an aliphatic alcohol having 1 to 24 carbon atoms. X is represented by the above general formulas (a) to (f).)

[0046] Rosin contains diterpenoid acid compounds called resin acids (rosin acids). The resin acids contained in rosin are mainly abietic acid, but in addition to this abietic acid, there are neoabietic acid, dehydroabietic acid, tetrahydroabietic acid, palustric acid, pimaric acid, isopimaric acid, sandaracopimaric acid, levopimaric acid, etc.

[0047] R in general formula (1) 1 The "residue obtained by removing carboxylic acid from rosin" in means the residue obtained by removing carboxylic acid from the resin acid constituting rosin. That is, for example, the residue obtained by removing carboxylic acid from abietic acid, the residue obtained by removing carboxylic acid from palustric acid, etc. correspond. From this, the "residue obtained by removing carboxylic acid from rosin" usually contains two or more "residues obtained by removing carboxylic acid from rosin", but may also be a single residue (for example, the residue obtained by removing carboxylic acid from abietic acid).

[0048] In addition, the rosin of the acyl residue of rosin in general formula (1-1) is the same, and the "acyl residue of rosin" means the acyl residue of carboxylic acids such as resin acids constituting rosin. 4

[0049] (1-1-2) Compounds represented by general formulas (1-1) to (1-5): Among the compounds represented by the general formula (1), the anionic surfactant is more preferably at least one selected from the compounds represented by the above general formulas (1-1) to (1-5). By containing these compounds, the amount of carbon dioxide absorbed by the hardened body of the hydraulic composition can be further increased.

[0050] Regarding the compounds represented by the general formulas (1-3) to (1-5), the anionic surfactant can be constituted by a mixture thereof. Regarding these composition ratios, they can be determined by measuring the P nuclear NMR integration ratio.

[0051] The method for measuring the P nuclear NMR integration ratio is shown below. First, an excess of KOH is added to a mixture of the compounds (phosphoric acid esters) represented by the general formulas (1-3) to (1-5) to make the pH 12 or higher. Next, under this condition (that is, the condition of performing alkali over-neutralization pretreatment with KOH), 31 P-NMR (specifically, a product name MERCURY plus NMR Spectrometor System manufactured by Varian, 300 MHz) measurement is performed, and using the obtained measurement values, the P nuclear NMR integration ratio can be calculated based on the following formulas (a) to (c). Note that 31 As the solvent in the P-NMR measurement, a mixed solvent of heavy water / tetrahydrofuran = 8 / 2 (volume ratio) can be used.

[0052]

Number

[0053]

Number

[0054]

Number

[0055] In the above formulas (a) to (c), P conversion 1, P conversion 2, and P conversion 3 are as shown below. P conversion 1: The P nuclear NMR integral value attributed to the compound (phosphoric acid ester) represented by the general formula (1-3) P conversion 2: The P nuclear NMR integral value attributed to the compound (phosphoric acid ester) represented by the general formula (1-4) P conversion 3: The P nuclear NMR integral value attributed to the compound (phosphoric acid ester) represented by the general formula (1-5)

[0056] "Alkali over-neutralization pretreatment" means a pretreatment in which an excessive amount of alkali is added to the phosphoric acid ester. 31 In the measurement of P-NMR, when this "alkali over-neutralization pretreatment" is performed, the peaks attributed to the phosphoric acid ester can be clearly separated, and the calculation of the P nuclear NMR integral ratio attributed to each compound according to the above formulas (a) to (c) becomes possible.

[0057] (1-1-3) Compound represented by the general formula (1-1a): The compound represented by the general formula (1-1) is preferably the compound represented by the following general formula (1-1a). And in the present invention, the anionic surfactant is preferably a mixture containing the compound represented by the following general formula (1-1a) and at least one selected from the compounds represented by the general formulas (1-2) to (1-5). By containing these compounds, the amount of carbon dioxide absorbed by the hardened body of the hydraulic composition can be further increased.

[0058]

Chemical formula

[0059] R in the general formula (1-1a) 11 is an alkyl group having 6 to 20 carbon atoms or an alkenyl group having 6 to 20 carbon atoms.

[0060] M in the general formula (1-1a) 16 is hydrogen, an alkali metal, an alkaline earth metal, or an organic amine.

[0061] (1-2) Other components: The carbonation accelerator for the hydraulic composition of the present invention can contain other components in addition to the above anionic surfactant as long as the effects are not impaired.

[0062] As the other components, for example, water and additives added to conventionally known hydraulic compositions can be appropriately selected and employed.

[0063] Note that the other components may be used alone or in combination of two or more.

[0064] The carbonation accelerator for the hydraulic composition of the present invention is preferably added to the hydraulic composition described later.

[0065] (2) Hydraulic composition: The carbonation accelerator for the hydraulic composition of the present invention can be added to and used in a hydraulic composition. This hydraulic composition can include a binder (hydraulic binder), water, and aggregates (fine aggregates, coarse aggregates) in the same manner as conventionally known hydraulic compositions.

[0066] There is no particular limitation on the content ratio of the carbonation accelerator for the hydraulic composition of the present invention in the hydraulic composition, and it can be appropriately set. For example, the content ratio of the carbonation accelerator for the hydraulic composition of the present invention can be 0.0005 to 2% by mass based on 100% by mass of the binder.

[0067] Examples of the binder include various Portland cements such as ordinary Portland cement, medium heat Portland cement, low heat Portland cement, early strength Portland cement, sulfate resistant Portland cement, and various cements such as blast furnace cement, fly ash cement, and silica fume cement.

[0068] Furthermore, as the binder, various admixtures such as fly ash, blast furnace slag fine powder, limestone fine powder, stone powder, silica fume, expansive agent, anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum may be used in combination with the various cements described above.

[0069] In addition, the binder preferably contains 40 to 99% by mass of blast furnace slag fine powder. That is, the hydraulic composition to which the carbonation promoter for the hydraulic composition of the present invention is added preferably contains a binder containing 40 to 99% by mass of blast furnace slag fine powder, water, and aggregate. The content ratio of the blast furnace slag fine powder is preferably 50 to 99% by mass, and more preferably 60 to 99% by mass. By doing so, the carbon dioxide balance of the hydraulic composition can be further reduced.

[0070] Examples of the aggregate include fine aggregate and coarse aggregate.

[0071] Examples of the fine aggregate include river sand, mountain sand, land sand, sea sand, silica sand, crushed sand, various slag fine aggregates, and various recycled fine aggregates, and those containing fine particle components such as clay may also be used.

[0072] Examples of the coarse aggregate include river gravel, mountain gravel, land gravel, crushed stone, various slag coarse aggregates, lightweight aggregate, and various recycled coarse aggregates.

[0073] The hydraulic composition preferably contains γ-2CaO·SiO2. That is, the carbonation accelerator for the hydraulic composition of the present invention is preferably added to the hydraulic composition containing γ-2CaO·SiO2. By doing so, since γ-2CaO·SiO2 exhibits the function of immobilizing carbon dioxide, the amount of carbon dioxide absorbed by the hardened body of the hydraulic composition (i.e., the amount of carbon dioxide reduction) can be further increased. As a result, the carbon dioxide balance of the hydraulic composition can be further reduced. This γ-2CaO·SiO2 is a material that hardens by carbonation. Note that γ-2CaO·SiO2 may be added to a hydraulic composition containing a binder containing 40 to 99% by mass of blast furnace slag fine powder, water, and aggregate, or to a hydraulic composition not containing these binders and the like.

[0074] The content ratio of γ-2CaO·SiO2 is not particularly limited, but for example, it can be set to a ratio corresponding to 1 to 30% by mass on an internal basis with respect to 100% by mass of the binder.

[0075] The hydraulic composition preferably contains at least one selected from the following CO2-fixing fine powder and the following CO2-fixing modified recycled fine aggregate. By doing so, the carbon dioxide balance of the hydraulic composition can be further reduced. Note that CCU (Carbon Capture and Utilization) materials such as CO2-fixing fine powder and CO2-fixing modified recycled aggregate (including CO2-fixing modified recycled fine aggregate) are powders and aggregates produced by previously reacting CO2 with calcium components derived from waste such as waste concrete, and the CCU materials may be used in carbon-neutral or carbon-negative concrete. In addition to the CO2-fixing modified recycled fine aggregate, the hydraulic composition may further employ a CO2-fixing modified recycled coarse aggregate, or may employ a CO2-fixing modified recycled coarse aggregate instead of the CO2-fixing modified recycled fine aggregate.

[0076] (CO2-fixing fine powder) The CO2-fixing fine powder has a particle size of 50 μm or less for 50% of the particles, and contains a modified concrete powder which is a reaction product of recycled concrete powder and carbon dioxide gas. This modified concrete powder contains calcium carbonate and silicate. And the content ratio of the CO2-fixing fine powder is in the range of 1 to 100% by mass based on 100% by mass of the binder.

[0077] The CO2-fixing fine powder can be produced as follows. That is, first, a concrete block is crushed or ground, and recycled concrete fine powder with a median diameter of 100 μm or less is recovered. There are no particular restrictions on the method of performing this crushing or grinding, and known crushing devices or grinding devices such as shot blasting type crushing devices, impact crushers, and mechanical abrasion type grinding devices without heating can be used. Next, the recovered recycled concrete fine powder is reacted with carbon dioxide gas at a volume concentration of 5% or more to fix CO2 to the cement-derived components contained in the recycled concrete fine powder. The reaction with carbon dioxide gas may be a dry method in which gaseous carbon dioxide gas is brought into contact, or any of wet methods in which the recycled concrete fine powder is immersed in a solution such as water and then carbon dioxide gas is blown into this liquid (dispersion) to bring them into contact. In this way, the CO2-fixing fine powder can be produced.

[0078] (CO2-fixed modified recycled aggregate) The CO2-fixed modified recycled aggregate is an aggregate produced by previously reacting CO2 with calcium components derived from waste such as waste concrete. Examples include CO2-fixed modified recycled fine aggregate and CO2-fixed modified recycled coarse aggregate. Among these, since it contains more cement-derived calcium components, has a larger CO2 fixation amount during the production of the CO2-fixed modified recycled aggregate (i.e., the "emission amount of carbon dioxide derived from the material" is small), and has a large reduction effect on the carbon dioxide balance when applied to a hydraulic composition, it is preferable to use the CO2-fixed modified recycled fine aggregate.

[0079] (CO2-fixed modified recycled fine aggregate) The CO2-fixed modified recycled fine aggregate has a particle size of 10 mm or less for all particles, with 85% or more of them being 5 mm or less, and a water absorption rate exceeding 3.0% and being 10% or less. It includes the modified recycled fine aggregate that is a dry or wet reaction product of the recycled fine aggregate and carbon dioxide gas. The modified recycled fine aggregate contains calcium carbonate and silicon dioxide. And the content ratio of the CO2-fixed modified recycled fine aggregate is in the range of 10 to 100 volume % with respect to the total aggregate volume.

[0080] The CO2-fixed modified recycled fine aggregate can be manufactured as follows. That is, first, the concrete block is crushed or ground to obtain the recycled fine aggregate. There are no particular restrictions on the method of performing this crushing or grinding, and known crushing devices or grinding devices such as shot blasting type crushing devices, impact crushers, and mechanical rubbing and grinding devices without heating can be used. Then, the particles with a particle size of 10 mm or less for all particles are classified, and among them, the particles with a water absorption rate exceeding 3% and being 10% or less are used as the recycled fine aggregate. Next, the recycled fine aggregate is reacted with carbon dioxide gas at a volume concentration of 5% or more to obtain the CO2-fixed modified recycled fine aggregate containing calcium carbonate and silicon dioxide. The reaction between the recycled fine aggregate and carbon dioxide gas may adopt a dry method or a wet method. In this way, the CO2-fixed modified recycled fine aggregate can be manufactured.

[0081] The content ratio of the CO2-fixed fine powder is 1 to 100 mass %, preferably 10 to 90 mass %, and more preferably 30 to 80 mass % with respect to 100 mass % of the binder as described above.

[0082] The content ratio of the CO2-fixed modified recycled fine aggregate is 10 to 100 volume %, preferably 20 to 100 volume %, and more preferably 30 to 100 volume % with respect to the total aggregate volume (more specifically, the aggregate volume using the original formulated natural aggregate) as described above.

[0083] Here, the original mixture refers to a mixture that does not use CO2-fixed modified recycled fine aggregates. Also, natural aggregates refer to aggregates that have not been subjected to CO2 fixation treatment. For example, in the case of fine aggregates, it includes river sand, mountain sand, land sand, sea sand, silica sand, crushed sand, various slag fine aggregates, etc. In the case of coarse aggregates, it includes, for example, river gravel, mountain gravel, land gravel, crushed stone, various slag coarse aggregates, lightweight aggregates, etc. That is, "with respect to the aggregate volume using the natural aggregates of the original mixture" means with respect to the volume of natural aggregates such as river sand as in the past. That is, conventionally, CO2-fixed modified recycled fine aggregates may be used instead of what has been used as aggregates (100% by volume), or about 1 / 5 (i.e., 20% by volume) may be replaced and used.

[0084] The hydraulic composition may further contain other constituent components as appropriate within a range where the effects are not impaired. Examples of such other constituent components include saccharides, setting retardation components composed of oxycarboxylates, etc., components having a dispersing action composed of sodium lignosulfonate, etc., defoaming agents composed of oxyalkylene compounds, etc., hardening accelerators composed of alkanolamines, etc., shrinkage reducing agents composed of polyoxyalkylene alkyl ethers, etc., thickeners composed of cellulose ether compounds, etc., preservatives composed of isothiazoline compounds, etc., rust preventives composed of nitrites, etc.

[0085] As the content ratio of other constituent components, for example, it can be 0 to 5% by mass with respect to 100% by mass of the binder.

[0086] As the ratio of water to binder (water / binder ratio) of the hydraulic composition, a conventionally known ratio can be appropriately adopted. For example, it can be 25 to 70% by mass.

[0087] The hydraulic composition can be cured to form a cured body of the hydraulic composition (specifically, mortar or concrete). When obtaining such a cured body of the hydraulic composition, it is preferable to go through a carbonation curing process, which is a process of curing in an environment with a carbon dioxide volume concentration of 5% or more. By going through such a carbonation curing process, a large amount of carbon dioxide can be absorbed and immobilized in the hydraulic composition (cured body of the hydraulic composition).

[0088] Note that the volume concentration of carbon dioxide in the carbonation curing process is not particularly limited, but it can usually be 5 to 100%.

[0089] (3) Method for manufacturing a cured body of a hydraulic composition: The method for manufacturing a cured body of the hydraulic composition of the present invention includes a preparation step of preparing a hydraulic composition containing at least the carbonation accelerator for the hydraulic composition of the present invention, a binder containing 40 to 99% by mass of fine blast furnace slag powder, and water, a curing step of curing the obtained hydraulic composition to obtain a cured body of the hydraulic composition, and a carbonation curing step of curing the obtained cured body of the hydraulic composition in an environment with a carbon dioxide volume concentration of 5% or more to absorb and immobilize carbon dioxide in the cured body of the hydraulic composition. According to such a method for manufacturing a cured body of a hydraulic composition, since a hydraulic composition containing the carbonation accelerator for the hydraulic composition of the present invention is used, the amount of carbon dioxide reduced in the manufacturing process increases.

[0090] (3-1) Preparation step: The preparation step is a step of preparing a hydraulic composition containing at least the carbonation accelerator for the hydraulic composition of the present invention, a binder containing 40 to 99% by mass of fine blast furnace slag powder, and water.

[0091] The fine blast furnace slag powder is contained at 40 to 99% by mass as described above, preferably 50 to 99% by mass, and more preferably 60 to 99% by mass. By setting the above content ratio, the amount of carbon dioxide reduced in the manufacturing process of the cured body of the hydraulic composition increases.

[0092] (3-2) Curing step: The hardening process is a process of hardening the hydraulic composition obtained in the preparation process to obtain a hardened body of the hydraulic composition. As the method for hardening the hydraulic composition, a conventionally known method can be appropriately adopted.

[0093] (3-3) Carbonation curing process: The carbonation curing process is a process of curing the hardened body of the hydraulic composition obtained in the hardening process in an environment with a carbon dioxide volume concentration of 5% or more (carbonation curing) to absorb and immobilize carbon dioxide in the hardened body of the hydraulic composition.

[0094] In this process, carbon dioxide in the atmosphere is absorbed by the hardened body of the hydraulic composition, carbonated, and fixed. By using the carbonation accelerator for the hydraulic composition of the present invention, the following is speculated. That is, fine bubbles are uniformly carried in the hydraulic composition. Therefore, in the hardened body of the hydraulic composition, a flow path through which gas (carbon dioxide) flows from the outer surface toward the central part is favorably formed. And by forming this flow path, it becomes easier for carbon dioxide to flow into the central part of the hardened body of the hydraulic composition, and more carbon dioxide can be absorbed and immobilized in the hydraulic composition (hardened body of the hydraulic composition).

[0095] The volume concentration of carbon dioxide is not particularly limited, but it can usually be 5 to 100%.

[0096] In addition, when the volume concentration of carbon dioxide is less than 5%, the amount of carbon dioxide absorbed is too small, so the carbonation curing period until a predetermined carbon dioxide fixation amount is reached may be prolonged.

Examples

[0097] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

[0098] (Examples 1 to 48, Comparative Examples 1 to 12) (1) Carbonation accelerator for hydraulic composition: First, the carbonation accelerators A-1 to A-16 and RA-1 to RA-2 for hydraulic compositions of Examples and Comparative Examples were prepared with the formulations shown in Table 1 below.

[0099]

Table 1

[0100] Next, Table 2 below specifically shows each of the essential components (anionic surfactants a-1 to a-18) and other components (b-1 to b-5) shown in Table 1. b-5 is "the product name "Skishu 21B" (special polycarboxylic acid type surfactant) manufactured by Kao Corporation".

[0101]

Table 2

[0102] The manufacturing methods of each anionic surfactant (a-1 to a-18) will be specifically described below.

[0103] For the anionic surfactant (a-1), oleic acid from Tokyo Chemical Industry Co., Ltd. was used. For the anionic surfactant (a-13), sodium branched-chain dodecylbenzenesulfonate from Tokyo Chemical Industry Co., Ltd. was used. For the anionic surfactant (a-14), sodium linear dodecylbenzenesulfonate from Tokyo Chemical Industry Co., Ltd. was used. For the anionic surfactant (a-15), sodium decyl sulfate from Kao Corporation was used. For the anionic surfactant (a-16), sodium higher alcohol ethoxysulfate from Teika Corporation was used. For the anionic surfactant (a-17), sodium tetradecenesulfonate (sodium α-olefin sulfonate) from Lion Specialty Chemicals Co., Ltd. was used. For the anionic surfactant (a-18), sodium sec-alkyl (C14-17) sulfonate from Clariant was used.

[0104] In addition, when the anionic surfactants (a-1 to a-12) are classified into the compounds represented by the general formulas (1-1) to (1-5), the anionic surfactants a-1 to a-4 and a-12 correspond to the compounds represented by the general formula (1-1), and the anionic surfactants a-10 to a-11 correspond to the compounds represented by the general formula (1-2). The anionic surfactants a-5 to a-9 are a mixture of the compounds represented by the general formulas (1-3) to (1-5). The anionic surfactants a-13 to a-18 are compounds containing organic acid ions having a hydrophobic group with 6 to 50 carbon atoms in the molecule.

[0105] Anionic surfactant a-2: After charging 437.91 g of ion-exchanged water and 18.17 g of a 48% potassium hydroxide aqueous solution into the reaction vessel, the mixture was heated to 40 °C. 43.92 g of oleic acid (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.) was added thereto while stirring. After sufficient stirring, aging was carried out for 1 hour. In this way, a 10% aqueous solution of potassium oleate (anionic surfactant a-2) was obtained.

[0106] Anionic surfactants a-3, a-4: For the anionic surfactants a-3 and a-4, synthesis was carried out in the same manner as for the anionic surfactant a-2, except that the types and charging ratios of the compounds (raw material fatty acids and alkalis used for neutralization) used were changed.

[0107] Anionic surfactant a-5: 221.44 g of 1-octanol (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.) was charged into the reaction vessel, and dehydration treatment was carried out at 120 °C under the condition of 0.05 MPa for 2 hours. Then, the pressure was returned to atmospheric pressure, and 78.56 g of phosphorus pentoxide was added dropwise over 0.5 hour while stirring at 60 ± 5 °C. After aging at 80 °C for 3 hours, 200.00 g of ion-exchanged water was added and aging was carried out for 0.5 hour to obtain a 60% aqueous solution of phosphate ester (a-5) which is the anionic surfactant a-5.

[0108] Anionic surfactant a-6-1: After charging 407.11 g of ion-exchanged water and 71.29 g of a 60% aqueous solution of phosphoric ester (a-5) into the reaction vessel, the mixture was heated to 50°C. 21.61 g of a 48% aqueous potassium hydroxide solution was added dropwise thereto for neutralization to obtain a 10% aqueous solution of phosphoric ester (a-6-1), which is anionic surfactant a-6-1.

[0109] Anionic surfactant a-6-2: 136.53 g of 1-octanol (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.) was charged into the reaction vessel and dehydrated at 120°C under the condition of 0.05 MPa for 2 hours. After returning to atmospheric pressure, 86.93 g of phosphorus pentoxide was added over 0.5 hour at 60 ± 5°C with stirring. After aging at 80°C for 3 hours, 47.74 g of ion-exchanged water was added and aged for 0.5 hour. 228.81 g of a 48% aqueous potassium hydroxide solution was added dropwise thereto at 50°C for neutralization to obtain a 60% aqueous solution of phosphoric ester (a-6-2). Thereafter, it was adjusted to 10% with ion-exchanged water to obtain a 10% aqueous solution of anionic surfactant a-6-2.

[0110] Anionic surfactant a-7: For anionic surfactant a-7, synthesis was carried out in the same manner as for anionic surfactant a-5, except that the type of the compound (raw material alcohol) used and the charging ratio of the raw material alcohol to phosphorus pentoxide were changed.

[0111] Anionic surfactant a-8: (Synthesis of poly(5 mol) oxyethylene octyl ether) 371.58 g of 1-octanol (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.) and 1.0 g of potassium hydroxide were charged into a pressure vessel equipped with a stirrer, a pressure gauge and a thermometer. Subsequently, while maintaining the reaction system at 150 ± 5°C, 628.42 g of ethylene oxide was added at a gauge pressure of 0.4 MPa over 4 hours, and 150 ± 5°C was maintained for 1 hour to complete the reaction. Thereafter, neutralization was carried out using "Kyoward 600 (manufactured by Kyowa Chemical Industry Co., Ltd.)", and filtration was carried out to obtain poly(5 mol) oxyethylene octyl ether.

[0112] (Phosphorylation) Next, 210.96 g of the obtained poly(5 mol) oxyethylene octyl ether was charged into another reaction vessel, dehydrated at 120 °C for 2 hours under the condition of 0.05 MPa or less, then returned to atmospheric pressure, and 47.35 g of phosphorus pentoxide was added dropwise over 0.5 hours at 60 ± 5 °C with stirring. After aging at 80 °C for 3 hours, 117.06 g of ion-exchanged water was added and aged for 0.5 hours. To this, 124.63 g of a 48% aqueous potassium hydroxide solution was added dropwise at 50 °C for neutralization to obtain a 60% aqueous solution of the phosphate ester (a-8). Then, it was adjusted to 10% with ion-exchanged water to obtain a 10% aqueous solution of the anionic surfactant a-8.

[0113] Anionic surfactant a-9: For the anionic surfactant a-9, synthesis was carried out in the same manner as for the anionic surfactant a-6-1, except that the type of the compound (raw material alcohol) used and the charging ratio of the raw material alcohol to phosphorus pentoxide were changed.

[0114] Anionic surfactant a-10: 298.6 g of ion-exchanged water and 90.3 g of a 48% aqueous potassium hydroxide solution were charged into a reaction vessel, uniformly dissolved with stirring, and then the temperature of the reaction system was maintained at 40 °C in a warm water bath. Next, 111.1 g of dodecenyl succinic anhydride (reagent, manufactured by Tokyo Chemical Industry Co., Ltd., a mixture of branched-chain isomers) was added dropwise over 1 hour for neutralization, and then stirred at 45 °C for 2 hours. After the neutralization reaction, 913.09 g of ion-exchanged water was added and stirred well. In this way, a 10% aqueous solution of the anionic surfactant a-10 was obtained.

[0115] Anionic surfactant a-11: The anionic surfactant a-11 was synthesized in the same manner as the anionic surfactant a-10, except as shown in Table 1.

[0116] Anionic surfactant a-12: After charging 701.7 g of ion-exchanged water and 76.3 g of a 48% potassium hydroxide aqueous solution into the reaction vessel, the mixture was heated to 90 °C. 222.0 g of rosin (reagent, manufactured by Fuji Film Wako Pure Chemical Corporation) was added thereto while stirring. After the addition, aging was carried out for 1 hour to obtain a 25% aqueous solution of potassium rosin, which is an anionic surfactant a-12.

[0117] (Mass average molecular weight) The mass average molecular weights of the respective anionic surfactants (a-1 to a-18) are shown in the column of "Molecular weight" in Table 2. The mass average molecular weight was measured using gel permeation chromatography (GPC) under the following conditions. <Measurement conditions> Apparatus: Shodex GPC-101 (manufactured by Showa Denko KK) Column: OHpak SB-G + SB-804M HQ + SB-802.5M HQ (manufactured by Showa Denko KK) Detector: Differential refractometer (RI) Eluent: 50 mM sodium nitrate aqueous solution Flow rate: 0.7 mL / min Column temperature: 40 °C Sample concentration: Eluent solution with a sample concentration of 0.5 mass% Standard substance: PEG / PEO (manufactured by Agilent Technologies)

[0118] (P nuclear NMR integration ratio) Each of the anionic surfactants a-5 to a-9 shown in Table 2 is a mixture of compounds represented by general formulas (1-3) to (1-5). Therefore, the P nuclear NMR integration ratios attributed to each of the compounds represented by general formulas (1-3) to (1-5) were measured. The results are shown in Table 2. In "P nuclear NMR integration ratio" in Table 2, "mono" indicates the P nuclear NMR integration ratio attributed to the compound represented by general formula (1-3), "di" indicates the P nuclear NMR integration ratio attributed to the compound represented by general formula (1-4), and "poly" indicates the P nuclear NMR integration ratio attributed to the compound represented by general formula (1-5).

[0119] The P nuclear NMR integration ratio was first determined by adding an excess of KOH to each prepared phosphate ester (organic phosphate ester) to bring the pH to 12 or higher. Next, under this condition (i.e., the condition after the alkali over-neutralization pretreatment with KOH), 31 P-NMR (specifically, a product named MERCURY plus NMR Spectrometor System manufactured by Varian, 300 MHz) measurement was performed, and the P nuclear NMR integration ratio was calculated based on the following formulas (a) to (c) using the obtained measurement values. Note that 31 As the solvent for the P-NMR measurement, a mixed solvent of heavy water / tetrahydrofuran = 8 / 2 (volume ratio) was used.

[0120]

Number

[0121]

Number

[0122]

Number

[0123] In the above formulas (a) to (c), P-1, P-2, and P-3 are as shown below. P-1: The P nuclear NMR integration value attributed to the compound (phosphate ester) represented by the general formula (1-3) P-2: The P nuclear NMR integration value attributed to the compound (phosphate ester) represented by the general formula (1-4) P-3: The P nuclear NMR integration value attributed to the compound (phosphate ester) represented by the general formula (1-5)

[0124] (2) Hydraulic composition: Next, hydraulic compositions (mortars) were prepared using the formulations C-1 to C-3 shown in Table 3.

[0125] Specifically, first, into the kneading machine specified in JIS R5201, using the mixtures C-1 to C-3 (mortar mixtures) shown in Table 3, ordinary Portland cement (manufactured by Taiheiyo Cement Corporation, density 3.16 g / cm 3 ), blast furnace slag fine powder #4000 (manufactured by Essement Chubu Co., Ltd., density 2.89 g / cm 3 ), carbonation admixture LEAF mainly composed of γ-2CaO·SiO2 (manufactured by Denka Co., Ltd., density 3.09 g / cm 3 ), fine aggregate (Oigawa River system land sand, density 2.58 g / cm 3 ), carbon dioxide (CO2) fixing fine powder (CCU fine powder; density 2.51 g / cm 3 ), and carbon dioxide (CO2) fixing modified recycled aggregate (CCU recycled fine aggregate; density 2.42 g / cm 3 ) were sequentially charged, and then dry-kneaded for 10 seconds. Here, the ordinary Portland cement, blast furnace slag fine powder, and carbonation admixture were regarded as binders.

[0126] In addition, the CO2 fixing fine powder and the CO2 fixing modified recycled aggregate are specifically shown below.

[0127] The CO2 fixing fine powder has a 50% particle size of 50 μm or less, contains modified concrete powder which is a reaction product of recycled concrete powder and carbon dioxide gas, and contains calcium carbonate and silicate.

[0128] This CO2 fixing fine powder was specifically manufactured as follows. That is, the concrete block was crushed and ground by a known crusher to obtain recycled concrete fine powder with a median diameter of 100 μm or less. Subsequently, 1800 kg of water and 200 kg of the obtained recycled concrete fine powder were sequentially charged into a container with a volume of 2 m 3 and stirred, and further, carbon dioxide gas was injected from the bottom of the container at a rate of 150 L / min to react the recycled concrete fine powder with CO2. The above reaction treatment was continued until the pH of the dispersion became 6.8 or less, and then a reaction product of the recycled concrete fine powder and CO2 was obtained. After the reaction was completed, the obtained reaction product was taken out, excess moisture was removed with a polypropylene twill filter, and then air-dried to obtain the CO2 fixing fine powder.

[0129] The CO2-fixed modified recycled aggregate (specifically, the CO2-fixed modified recycled fine aggregate) includes a modified recycled fine aggregate which is a dry or wet reaction product of a recycled fine aggregate having a water absorption rate of more than 3.0% and 10% or less and carbon dioxide gas, and contains calcium carbonate, silicon dioxide, and gypsum.

[0130] This CO2-fixed modified recycled aggregate was specifically manufactured as follows. That is, the concrete block was crushed and ground by a known crusher, and then classified by a sieve so that all particle diameters of the particles became particles of 10 mm or less. Among them, particles having a water absorption rate exceeding 3% and 10% or less were obtained as recycled fine aggregates. Subsequently, 1800 kg of water and 200 kg of the obtained recycled fine aggregate were sequentially charged into a container with a capacity of 2 m 3 and stirred, and further, carbon dioxide gas was injected from the bottom of the container at a rate of 150 L / min to react the recycled fine aggregate with CO2. The above reaction treatment was continued until the pH of the dispersion became 6.8 or less, and then a reaction product of the recycled fine aggregate and CO2 was obtained. After the reaction was completed, the obtained reaction product was taken out, excess moisture was removed with a twill filter made of polypropylene, and then air-dried to obtain the CO2-fixed modified recycled fine aggregate.

[0131] Next, a carbonation accelerator for the hydraulic composition shown in Table 1, a water reducing agent (high-performance water reducing agent Tuperpol NV-80 (trade name) manufactured by Takemoto Yushi Co., Ltd.), and an antifoaming agent (AFK-2 (trade name) manufactured by Takemoto Yushi Co., Ltd.) were kneaded and added to water (however, the above carbonation accelerator, water reducing agent, and antifoaming agent are regarded as a part of the water). Then, this kneaded water was put into a kneader and kneaded for 180 seconds to obtain a hydraulic composition (mortar).

[0132] In addition, the antifoaming agent was added at 0.0005% by mass based on the binder (however, the antifoaming agent was not added in Comparative Examples 2, 5, and 8), and the carbonation accelerator for the hydraulic composition was adjusted and added within the range of 0.001% to 0.05% by mass based on the binder so that the air content of the mortar after mixing was within 4.5 ± 0.5%. However, in Comparative Examples 2, 5, and 8, the air content of the mortar after mixing was set to 4.5 ± 0.5% by high-speed stirring of the mixer during mortar mixing.

[0133] Also, the addition amount of the water reducing agent was set such that the mortar flow was within 200 ± 5 mm for Formulations C-1 and C-2, and the mortar flow was within 275 ± 5 mm for Formulation C-3.

[0134] [Table 3]

[0135] Regarding Formulations C-1 to C-3, the following relationships exist. Specifically, no carbonation admixture was used in Formulation C-1, while a carbonation admixture was used in Formulations C-2 and C-3. This carbonation admixture is 30% by mass based on the binder. In Formulation C-3, CCU fine powder was blended, and this CCU fine powder replaced 50% by mass of the fine aggregate outside the binder. Also, in Formulation C-3, CCU recycled fine aggregate was blended, and 100% of the fine aggregate was replaced with this CCU recycled fine aggregate.

[0136] In Table 3, the "carbon dioxide emissions from materials (α)" were calculated based on the amount of carbon dioxide emitted during the production of each component. That is, the carbon dioxide emissions of ordinary Portland cement are 764.3 kg / t, the carbon dioxide emissions of blast furnace slag fine powder are 26.5 kg / t, the carbon dioxide emissions of the carbonation admixture are 124.5 kg / t, the carbon dioxide emissions of CCU recycled fine aggregate are -26.9 kg / t, and the carbon dioxide emissions of CCU fine powder are -83.8 kg / t.

[0137] Tables 4 to 6 show the test results (mortar flow (mm), air content (%)) of the mortars prepared by adopting each of Formulations C-1 to C-3, and the results such as carbon dioxide balance. The numerical values in the column of "emission amount of carbon dioxide derived from materials (α)" in Tables 4 to 6 are the "emission amount of carbon dioxide derived from materials (α)" shown in Table 3.

[0138] In Examples 1 to 16 and Comparative Examples 1 and 2 shown in Table 4, based on the carbon dioxide balance of Comparative Example 3, the difference from the carbon dioxide balance in each example and comparative example was calculated, and the value of "carbon dioxide reduction amount" by the carbonation accelerator for hydraulic compositions was shown. In Examples 17 to 32 and Comparative Examples 5 and 6 shown in Table 5, based on the carbon dioxide balance of Comparative Example 7, the difference from the carbon dioxide balance in each example and comparative example was calculated, and the value of "carbon dioxide reduction amount" by the carbonation accelerator for hydraulic compositions was shown. In Examples 33 to 48 and Comparative Examples 9 and 10 shown in Table 6, based on the carbon dioxide balance of Comparative Example 11, the difference from the carbon dioxide balance in each example and comparative example was calculated, and the value of "carbon dioxide reduction amount" by the carbonation accelerator for hydraulic compositions was shown.

[0139] Here, in Comparative Examples 3, 7, and 11, only a water reducing agent is used without using a carbonation accelerator for hydraulic compositions. In Comparative Examples 3, 7, and 11, air is intentionally entrained into the hydraulic composition by high-speed stirring of the hydraulic composition. However, the entrained air is coarser than that in the case of using a carbonation accelerator for hydraulic compositions. Since the carbon dioxide balances of Comparative Examples 4, 8, and 12 are respectively larger than those of Comparative Examples 3, 7, and 11, the "carbon dioxide reduction amount" has not been calculated.

[0140] The measuring methods of mortar flow (mm) and air content (%) for the hydraulic composition are shown below.

[0141] (Mortar flow) For the hydraulic composition immediately after remixing, it was measured in a state without falling motion in accordance with JIS R5201.

[0142] (Air volume (volume %)) For the hydraulic composition immediately after remixing, measurements were taken using a mortar container in accordance with JIS A1116.

[0143] (3) Method for manufacturing a hardened body of a hydraulic composition: (Hardening process of mortar) First, a formwork of a cylindrical tin concrete specimen mold (product name "Summit Mold", manufactured by Sumisho Cement Co., Ltd., diameter of the bottom surface of the mold 50 mm, height of the mold 100 mm) was prepared, and the prepared hydraulic composition (mortar) was filled into this formwork using a two-layer packing method.

[0144] Next, air curing (at 20 °C) was carried out indoors at 20 °C. Then, 2 hours after the preparation of the mortar, the surface of the filled mortar was leveled, and polyethylene wrap was applied so that moisture would not evaporate, and sealed curing was carried out until the age of 2 days. Then, a specimen (mortar hardened body) was obtained.

[0145] (Carbonation curing process of mortar hardened body (hardened body of hydraulic composition)) After sealed curing, the specimen (mortar hardened body) was demolded from the mold, and carbonation curing (curing conditions: 20 °C, 60% RH, volume concentration of carbon dioxide 60%) was carried out until the age of 7 days in a high-concentration accelerated carbonation curing tank (manufactured by Marui Co., Ltd.) capable of controlling temperature, humidity, and carbon dioxide concentration. At this time, carbonation was carried out from the entire surface of the specimen without coating the specimen. In this way, a hardened body of the hydraulic composition was manufactured.

[0146] (Measurement of the fixed amount of carbon dioxide) For the manufactured hardened body of the hydraulic composition, the fixed amount of carbon dioxide was measured as follows.

[0147] (Method for preparing an analytical sample) After carbonation curing, the specimen (hardened body of the hydraulic composition) was taken out of the curing tank and immediately transferred to a furnace at 105 °C for a drying treatment for 2 days. After drying, the entire specimen was crushed, and then further crushed in a ball mill to a size of 150 μm or less, and this was used as an analytical sample.

[0148] (Method for measuring total carbon content and method for calculating CO2 fixation amount by carbonation curing) To confirm the amount of carbon dioxide fixed (CO2 fixation amount) by carbonation curing, the total carbon content (C (%)) in the analysis sample was measured using a total organic carbon meter ("TOC-L" manufactured by Shimadzu Corporation and a solid sample combustion device "SSM-5000A"). The measurement conditions were a sample amount of 50 mg and a combustion temperature of 900 °C.

[0149] From the obtained total carbon content, the CO2 fixation amount (%) in the analysis sample was calculated using the following formula, and the amount of carbon dioxide fixed (kg-CO2 / m 3 ) was calculated. Formula: CO2 (%) = C (%) × 44 / 12

[0150] Note that the CO2 fixation amount is the ratio to the sample weight after heat treatment at 900 °C. Also, the CO2 fixation amount by carbonation curing is calculated after subtracting the carbon amount detected from the materials used in the mortar (cement, blast furnace slag fine powder, carbonation accelerator, CO2-fixing fine powder, fine aggregate, CO2-fixing modified recycled aggregate (CO2-fixing modified recycled fine aggregate)) and the added components (water reducing agent, antifoaming agent, carbonation accelerator for hydraulic composition).

[0151] In Tables 4 to 6, "carbon dioxide balance (α-β)" is a value calculated by the formula: carbon dioxide emission amount from materials (α) - carbon dioxide fixation amount by carbonation curing (β). Also, "carbon dioxide reduction amount" is a value calculated by the formula: |"carbon dioxide balance" of each example - "carbon dioxide balance" of Comparative Examples 3, 7, and 11|. From the results of this "carbon dioxide reduction amount", it can be seen that in each example, the carbon dioxide absorption effect is excellent compared to the case of Comparative Examples 3, 7, and 11 which are the reference. That is, in each example, the carbonation of the hydraulic composition is promoted by the carbonation accelerator for hydraulic composition.

[0152]

Table 4

[0153] In addition, in Table 4, the evaluation of "carbon dioxide reduction amount" was based on the following evaluation criteria. S: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is 30 kg-CO2 / m 3 or more. A: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is 20 kg-CO2 / m 3 or more and less than 30 kg-CO2 / m 3 . B: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is 10 kg-CO2 / m 3 or more and less than 20 kg-CO2 / m 3 . C: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is less than 10 kg-CO2 / m 3 .

[0154] [Table 5]

[0155] In addition, in Table 5, the evaluation of "carbon dioxide reduction amount" was based on the following evaluation criteria. S: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is 30 kg-CO2 / m 3 or more. A: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is 20 kg-CO2 / m 3 or more and less than 30 kg-CO2 / m 3 . B: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is 10 kg-CO2 / m 3 or more and less than 20 kg-CO2 / m 3 . C: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is less than 10 kg-CO2 / m 3 .

[0156]

Table 6

[0157] In Table 6, the evaluation of the "carbon dioxide reduction amount" was based on the following criteria. S: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is 25 kg-CO2 / m 3 or more A: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is 20 kg-CO2 / m 3 or more and less than 25 kg-CO2 / m 3 B: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is 10 kg-CO2 / m 3 or more and less than 20 kg-CO2 / m 3 C: The carbon dioxide reduction amount (kg-CO2 / m 3 ) is less than 10 kg-CO2 / m 3

[0158] (Results) As shown in Tables 4 to 6, by adding the carbonation accelerator for the hydraulic composition of this example, it can be seen that the carbonation of the hydraulic composition is promoted and the amount of carbon dioxide reduction by the hydraulic composition (hydraulic composition hardened body) can be increased. Also, according to the manufacturing method of the hardened body of the hydraulic composition of this example, by using the carbonation accelerator for the hydraulic composition of this example as a raw material, it can be seen that the carbonation of the hydraulic composition is promoted and the amount of carbon dioxide absorbed by the manufactured hardened body of the hydraulic composition (carbon dioxide reduction amount) can be increased.

Industrial Applicability

[0159] ​​​The carbonation accelerator for hydraulic compositions of the present invention can be used as a raw material for a hardened body of a hydraulic composition that reduces carbon dioxide by adding it to the hydraulic composition. The method for producing a hardened body of a hydraulic composition of the present invention can be adopted as a method for producing a hardened body of a hydraulic composition that absorbs carbon dioxide.

Claims

1. containing an anionic surfactant in a proportion of 10 to 100% by mass, wherein the anionic surfactant is a compound containing an organic acid ion having a hydrophobic group with 6 to 50 carbon atoms in the molecule, and is a carbonation accelerator for a hydraulic composition.

2. The carbonation accelerator for a hydraulic composition according to claim 1, wherein the anionic surfactant is at least one compound selected from the compounds represented by the following general formula (1). 【Chemical 1】 (In general formula (1), R １ is an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, an aryl group having 8 to 20 carbon atoms, a residue obtained by removing carboxylic acid from rosin, or a residue obtained by removing hydrogen from a product obtained by adding 1 to 10 moles in total of an alkylene oxide having 2 to 3 carbon atoms per mole of an aliphatic alcohol having 1 to 24 carbon atoms. X is represented by the following general formulas (a) to (f).) 【Chemical 2】 【Chemical Formula 3】 【Chemical Formula 4】 【Chemical Formula 5】 【Chemical Formula 6】 【Chemical Formula 7】 (In general formulas (a) to (f), R ２ and R ３ are each independently a residue obtained by removing a hydroxyl group from an aliphatic alcohol having 1 to 24 carbon atoms, or a residue obtained by removing a hydroxyl group from a product obtained by adding alkylene oxide having 2 to 3 carbon atoms in a total amount of 1 to 10 moles per mole of an aliphatic alcohol having 1 to 24 carbon atoms. M １ to M ８ are each independently an alkali metal, an alkaline earth metal, ammonium, or an organic amine. n is an integer of 2 or 3.)

3. The carbonation accelerator for a hydraulic composition according to claim 1, wherein the anionic surfactant is at least one selected from the compounds represented by the following general formulas (1-1) to (1-5). 【Chemical 8】 (In the general formula (1-1), R ４ is an alkyl group having 6 to 20 carbon atoms, an alkenyl group having 6 to 20 carbon atoms, or an acyl residue of rosin. M ９ is hydrogen, an alkali metal, an alkaline earth metal, ammonium, or an organic amine.) 【Chemical Formula 9】 (In the general formula (1-2), R ５ is an alkyl group having 6 to 20 carbon atoms, an alkenyl group having 6 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. M １０ to M １１ is hydrogen, an alkali metal, an alkaline earth metal, ammonium, or an organic amine.) 【Chemical Formula 10】 (In the general formula (1-3), R ６ is a residue obtained by removing a hydroxyl group from an aliphatic alcohol having 6 to 20 carbon atoms, or a residue obtained by removing a hydroxyl group from a product obtained by adding 1 to 10 moles in total of an alkylene oxide having 2 to 3 carbon atoms per mole of an aliphatic alcohol having 6 to 20 carbon atoms. M １２ , M １３ is each independently hydrogen, an alkali metal, an alkaline earth metal, ammonium or an organic amine.) 【Chemical 11】 (In the general formula (1-4), R ７ , R ８ is each independently a residue obtained by removing a hydroxyl group from an aliphatic alcohol having 6 to 20 carbon atoms, or a residue obtained by removing a hydroxyl group from an aliphatic alcohol having 6 to 20 carbon atoms to which 1 to 10 moles of alkylene oxide having 2 to 3 carbon atoms are added per mole of the aliphatic alcohol. M １４ is hydrogen, an alkali metal, an alkaline earth metal, ammonium or an organic amine.) 【Chemical Formula 12】 (In the general formula (1-5), R ９ , R １０ is each independently a residue obtained by removing a hydroxyl group from an aliphatic alcohol having 6 to 20 carbon atoms, or a residue obtained by removing a hydroxyl group from a product obtained by adding a total of 1 to 10 moles of alkylene oxide having 2 to 3 carbon atoms per mole of an aliphatic alcohol having 6 to 20 carbon atoms. M １５ is hydrogen, an alkali metal, an alkaline earth metal, ammonium or an organic amine. m is an integer of 2 or 3.)

4. The anionic surfactant is a compound represented by the general formula (1-1a), and at least one selected from the compounds represented by the general formulas (1-2) to (1-5), and is a mixture, and is a carbonation accelerator for a hydraulic composition according to claim 3. 【Chemical Formula 13】 (In the general formula (1-1a), R １１ is an alkyl group having 6 to 20 carbon atoms or an alkenyl group having 6 to 20 carbon atoms. M １６ is hydrogen, an alkali metal, an alkaline earth metal, or an organic amine.)

5. Added to a hydraulic composition that becomes a hardened body of the hydraulic composition through a carbonation curing step, which is a curing step carried out in an environment with a volume concentration of carbon dioxide of 5% or more, and is the carbonation accelerator for a hydraulic composition according to any one of claims 1 to 4.

6. Added to a hydraulic composition containing a binder containing 40 to 99% by mass of blast furnace slag fine powder, water, and aggregate, and is the carbonation accelerator for a hydraulic composition according to any one of claims 1 to 4.

7. The hydraulic composition contains γ-2CaO·SiO ２ The carbonation accelerator for a hydraulic composition according to any one of claims 1 to 4, which contains ２ .

8. The hydraulic composition contains the following CO ２ fixed fine powder and the following CO ２ The carbonation accelerator for a hydraulic composition according to any one of claims 1 to 4, which contains at least one selected from fixed modified recycled fine aggregates. CO ２ Fixed fine powder: having a 50% particle size of 50 μm or less and containing a modified concrete powder that is a reaction product of recycled concrete powder and carbon dioxide gas, wherein the modified concrete powder contains calcium carbonate and silicate. However, the content ratio of the CO ２ in the hydraulic composition is in the range of 1 to 100% by mass with respect to 100% by mass of the binder. CO ２ Fixed modified recycled fine aggregate: all particle diameters of all particles are 10 mm or less, and 85% or more of them are 5 mm or less, and contains a modified recycled fine aggregate that is a reaction product of a recycled fine aggregate with a water absorption rate of more than 3.0% and 10% or less and carbon dioxide gas, either dry or wet, wherein the modified recycled fine aggregate contains calcium carbonate and silicon dioxide. However, the content ratio of the CO in the hydraulic composition ２ of the fixed modified recycled fine aggregate is in the range of 10 to 100% by volume based on the total aggregate volume.

9. A preparation step of preparing a hydraulic composition containing the carbonation accelerator for a hydraulic composition according to any one of claims 1 to 4, a binder containing 40 to 99% by mass of blast furnace slag fine powder, and water, a curing step of curing the obtained hydraulic composition to obtain a hardened body of the hydraulic composition, and a carbonation curing step of curing the obtained hardened body of the hydraulic composition in an environment with a volume concentration of carbon dioxide of 5% or more to absorb and immobilize carbon dioxide in the hardened body of the hydraulic composition. A method for producing a hardened body of a hydraulic composition, characterized by having

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