Hydraulic composition

Abstract

Provided is a hydraulic composition having fluidity, fluidity retention and strength development capabilities, and capable of reducing carbon dioxide balance. The hydraulic composition is characterized by including water, at least one aggregate selected from fine aggregate and coarse aggregate, a powder containing a binder, and an admixture. The hydraulic composition is also characterized by satisfying at least one condition selected from the conditions in which: the powder contains CO2-fixed fine powder; the fine aggregate contains a CO2-fixed modified regenerated fine aggregate; and the coarse aggregate contains CO2-fixed modified regenerated coarse aggregate. The hydraulic composition is further characterized in that the mass ratio of water to the binder contained in the powder (water / binder) is 0.3-0.9, and that the content of the admixture is 0.02-1.0 parts by mass with respect to 100 parts by mass of the binder.

Description

hydraulic composition

[0001] The present invention relates to a hydraulic composition, and more particularly to a hydraulic composition that has fluidity, fluidity retention, and strength development properties and reduces carbon dioxide balance.

[0002] In recent years, efforts to achieve a carbon-neutral or carbon-negative society have been accelerating around the world. For example, Japan declared in 2020 that it would achieve carbon neutrality by 2050, and in 2021 set a target of reducing greenhouse gas emissions by 46% by fiscal 2030 (compared to fiscal 2013 levels).

[0003] For example, the construction industry is also working to reduce carbon dioxide (CO2) emissions.

[0004] Specifically, concrete is a material that emits a large amount of carbon dioxide during its production, using cement that emits a large amount of carbon dioxide. Therefore, in order to reduce carbon dioxide emissions, low-carbon cement and low-carbon concrete, which use industrial by-products such as ground granulated blast furnace slag and fly ash to reduce the amount of cement used, are known.

[0005] It has also been reported that by using a cement admixture containing a non-hydraulic compound such as γ-2CaO·SiO2 and a predetermined proportion of eelimite, it is possible to ensure the initial strength of concrete while imparting strength reproducibility through carbonation curing (see Patent Document 1).

[0006] Japanese Patent Application Laid-Open No. 2023-28447

[0007] However, even when the cement admixture described in Patent Document 1 is used, there is still room for improvement in reducing the carbon dioxide balance (i.e., reducing the total amount of carbon dioxide emitted throughout the entire process of producing a hydraulic composition hardened body such as a concrete product). Furthermore, there is still room for improvement in the fluidity and fluidity retention of the obtained hydraulic composition, and there is also room for improvement in the strength development of a hydraulic composition hardened body produced from this hydraulic composition.

[0008] Therefore, there is a demand for the development of a hydraulic composition that can improve the reduction in carbon dioxide balance and also has improved fluidity, fluidity retention, and strength development.

[0009] In view of the above circumstances, an object of the present invention is to provide a hydraulic composition that has improved fluidity, fluidity retention, and strength development, and that can improve the reduction in carbon dioxide balance.

[0010] The phrase "improving the reduction in carbon dioxide balance" can be achieved by reducing the total amount of carbon dioxide emitted throughout the entire process of producing a hardened hydraulic composition such as a concrete product, or by using a material that has absorbed carbon dioxide. The material that has absorbed carbon dioxide is a CCU (Carbon Capture and Utilization) material such as CO2-fixing fine powder.

[0011] As a result of intensive research aimed at solving the above problems, the inventors have found that the above problems can be solved by containing CO2-fixing fine powder or CO2-fixing modified recycled aggregate and a predetermined binder, as well as a predetermined proportion of a predetermined admixture. According to the present invention, the following hydraulic composition is provided.

[0012] [1] A hydraulic composition comprising water, at least one aggregate selected from fine aggregate and coarse aggregate, a powder containing the binder described below, and the admixture described below, wherein the powder contains the CO2-fixing fine powder described below, the fine aggregate contains the CO2-fixing modified recycled fine aggregate described below, and the coarse aggregate contains the CO2-fixing modified recycled coarse aggregate described below, wherein the mass ratio of the water to the binder contained in the powder (water / binder) is 0.3 to 0.9, and the content of the admixture is 0.02 to 1.0 parts by mass per 100 parts by mass of the binder. Binder: A powder having hydraulic and latent hydraulic properties, containing 5 to 70 mass% Portland cement, 30 to 95 mass% ground granulated blast furnace slag, and 0 to 10 mass% gypsum based on the total mass of the binder. CO2-fixing fine powder: Includes modified concrete powder, which has a 50% particle size of 100 μm or less and is the reaction product of recycled concrete powder obtained from hardened concrete and carbon dioxide, the modified concrete powder containing calcium carbonate and silicates. CO2-fixing modified recycled fine aggregate: Includes modified recycled fine aggregate, which is the dry or wet reaction product of carbon dioxide and recycled fine aggregate obtained from hardened concrete and having a water absorption rate of more than 3.0% and not more than 10%, the modified recycled fine aggregate containing calcium carbonate and silicon dioxide. CO2-fixing modified recycled coarse aggregate: Includes modified recycled coarse aggregate, which is the dry or wet reaction product of carbon dioxide and recycled coarse aggregate obtained from hardened concrete and having a water absorption rate of more than 2.0% and not more than 7.0%, the modified recycled coarse aggregate containing calcium carbonate and silicon dioxide. Admixture: When the total content of structural unit 1 formed from a compound represented by the following general formula (1), structural unit 2 formed from a compound represented by the following general formula (2), and structural unit 3 formed from other copolymerizable monomers is taken as 100 mass%, the admixture comprises a water-soluble vinyl copolymer containing structural unit 1 in an amount of 50 to 99 mass%, structural unit 2 in an amount of 1 to 50 mass%, and structural unit 3 in an amount of 0 to 10 mass%.

[0013] (In general formula (1), R 1 , R 2 , R 3 are each independently a hydrogen atom or a methyl group. 4 is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. 5 O is an oxyalkylene group having 2 to 4 carbon atoms (however, when a plurality of oxyalkylene groups are present, one type may be used alone or two or more types may be used). n is R 5 is the average number of moles of O added, and is a number from 1 to 150. x is an integer from 0 to 5. y is an integer of 0 or 1.

[0014] (In general formula (2), R 6 , R 7 , R 8 are each independently a hydrogen atom, a methyl group, or [—(CH) p COOM 2 ] (wherein [-(CH2) p COOM 2 ] is COOM 1 or other COOM 2 In this case, M1 and M2 do not exist in the group. 1 , M 2 are each independently a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2), or an organic amine; and p is an integer of 0 to 2.

[0015] [2] The hydraulic composition according to [1], wherein the powder contains the CO2-fixed fine powder, and the content of the CO2-fixed fine powder is 1 to 100 parts by mass per 100 parts by mass of the binder.

[0016] [3] The hydraulic composition according to [1], wherein the fine aggregate contains the CO2 fixation modified recycled fine aggregate, and the CO2 fixation modified recycled fine aggregate is contained in an amount of 1 to 100 volume % of the total volume of the fine aggregate.

[0017] [4] The hydraulic composition according to [1], wherein the coarse aggregate contains the CO2 fixation modified recycled coarse aggregate, and the CO2 fixation modified recycled coarse aggregate is contained in a proportion of 1 to 100 volume % of the total volume of the coarse aggregate.

[0018] The hydraulic composition of the present invention has fluidity, fluidity retention and strength development properties, and further has the effect of reducing the carbon dioxide balance.

[0019] 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, modifications, etc. can be made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. In the following examples, % means % by mass, and parts means parts by mass, unless otherwise specified.

[0020] (1) Hydraulic composition: The hydraulic composition of the present invention contains water, at least one aggregate selected from fine aggregate and coarse aggregate, powder containing the binder described below, and the admixture described below, and satisfies at least one condition selected from the following: the powder contains the CO2-fixing fine powder described below; the fine aggregate contains the CO2-fixing modified recycled fine aggregate described below; and the coarse aggregate contains the CO2-fixing modified recycled coarse aggregate described below; the mass ratio of water to the binder contained in the powder (water / binder) is 0.3 to 0.9, and the content of the admixture is 0.02 to 1.0 part by mass per 100 parts by mass of the binder.

[0021] Such hydraulic compositions contain CO2-fixing fine powder or CO2-fixing modified recycled aggregate and a specified binder, as well as a specified proportion of a specified admixture, and therefore have fluidity, fluidity retention, and strength development properties, and can also reduce the carbon dioxide balance.

[0022] Binder: A powder with hydraulic and latent hydraulic properties, containing 5 to 70% by mass of Portland cement, 30 to 95% by mass of ground granulated blast furnace slag, and 0 to 10% by mass of gypsum relative to the total mass of the binder. CO2-fixing fine powder: A modified concrete powder with a 50% particle size of 100 μm or less, which is a reaction product of recycled concrete powder obtained from hardened concrete with carbon dioxide, the modified concrete powder containing calcium carbonate and silicates. CO2-fixing modified recycled fine aggregate: A modified recycled fine aggregate which is a dry or wet reaction product of carbon dioxide and recycled fine aggregate obtained from hardened concrete with a water absorption rate of more than 3.0% and not more than 10%, the modified recycled fine aggregate containing calcium carbonate and silicon dioxide. CO2-fixed modified recycled coarse aggregate: This includes modified recycled coarse aggregate, which is a dry or wet reaction product of carbon dioxide and recycled coarse aggregate obtained from hardened concrete and having a water absorption rate of more than 2.0% and not more than 7.0%, and the modified recycled coarse aggregate contains calcium carbonate and silicon dioxide. Admixture: This includes a water-soluble vinyl copolymer containing 50 to 99% by mass of structural unit 1, 1 to 50% by mass of structural unit 2, and 0 to 10% by mass of structural unit 3, where the total content of structural unit 1 formed from a compound represented by the following general formula (1), structural unit 2 formed from a compound represented by the following general formula (2), and structural unit 3 formed from other copolymerizable monomers is taken as 100% by mass.

[0023] (In general formula (1), R 1 , R 2 , R 3 are each independently a hydrogen atom or a methyl group. 4 is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. 5 O is an oxyalkylene group having 2 to 4 carbon atoms (however, when a plurality of oxyalkylene groups are present, one type may be used alone or two or more types may be used). n is R 5 is the average number of moles of O added, and is a number from 1 to 150. x is an integer from 0 to 5. y is an integer of 0 or 1.

[0024] (In general formula (2), R 6 , R 7 , R 8 are each independently a hydrogen atom, a methyl group, or [—(CH) p COOM 2 ] (wherein [-(CH2) p COOM 2 ] is COOM 1 or other COOM 2 In this case, M1 and M2 do not exist in the group. 1 , M 2 are each independently a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2), or an organic amine; and p is an integer of 0 to 2.

[0025] As described above, the hydraulic composition of the present invention must satisfy at least one of the following conditions: (i) the powder contains CO2-fixing fine powder; (ii) the fine aggregate contains CO2-fixing modified recycled fine aggregate; and (iii) the coarse aggregate contains CO2-fixing modified recycled coarse aggregate. In other words, the hydraulic composition of the present invention may satisfy any one of the conditions (i) to (iii) above, or may satisfy multiple conditions (i) to (iii) above. When multiple conditions (i) to (iii) above are satisfied, the combination of these conditions is not particularly limited and can be selected appropriately. Preferably, the hydraulic composition of the present invention combines the conditions (i) and (ii) above. Such a combination provides fluidity, fluidity retention, and strength development, and can further reduce the carbon dioxide balance.

[0026] Furthermore, when the above condition (i) is satisfied, that is, when the powder contains CO2-fixing fine powder, the content of the CO2-fixing fine powder is preferably 1 to 100 parts by mass, more preferably 10 to 100 parts by mass, and particularly preferably 20 to 100 parts by mass, per 100 parts by mass of the binder. By setting such a predetermined content ratio, the powder can have fluidity, flow retention, and strength development, and can further reduce the carbon dioxide balance.

[0027] Furthermore, when the above condition (ii) is satisfied, that is, when the fine aggregate contains CO2 fixation modified recycled fine aggregate, the CO2 fixation modified recycled fine aggregate is preferably contained in a proportion of 1 to 100 volume % of the total volume of the fine aggregate (more specifically, the volume of fine aggregate using the original natural aggregate). 25 to 100 volume % is more preferable, and 50 to 100 volume % is particularly preferable. By setting such a predetermined content ratio, the mixture can have fluidity, fluidity retention, and strength development, and can further reduce the carbon dioxide balance.

[0028] Furthermore, when the above condition (iii) is satisfied, that is, when the coarse aggregate contains CO2 fixation modified recycled coarse aggregate, the CO2 fixation modified recycled coarse aggregate is preferably contained in a proportion of 1 to 100 volume % of the total volume of the coarse aggregate (more specifically, the volume of the coarse aggregate using the original natural aggregate). A content of 25 to 100 volume % is preferred, and 50 to 100 volume % is particularly preferred. By achieving such a predetermined content, the mixture has fluidity, fluidity retention, and strength development, and can further reduce the carbon dioxide balance.

[0029] Here, "original mix" refers to a mix that does not use CO2 fixation and modified recycled fine aggregate or CO2 fixation and modified recycled coarse aggregate. Furthermore, "natural aggregate" refers to aggregate that has not been subjected to CO2 fixation treatment. Natural aggregate includes, for example, fine aggregates such as river sand, mountain sand, land sand, sea sand, silica sand, crushed sand, various slag fine aggregates, and various recycled fine aggregates, and coarse aggregates such as river gravel, mountain gravel, land gravel, crushed stone, various slag coarse aggregates, lightweight aggregate, and various recycled coarse aggregates. In other words, "relative to the fine aggregate volume (or coarse aggregate volume) using natural aggregate in the original mix" refers to the volume of natural aggregate, such as river sand, as in the past. In other words, CO2 fixation and modified recycled fine aggregate and CO2 fixation and modified recycled coarse aggregate may be used in place of aggregates conventionally used (i.e., 100% by volume), or may replace, for example, about 1 / 5 (i.e., 20% by volume).

[0030] (1-1) Aggregate: The aggregate is at least one selected from fine aggregate and coarse aggregate.

[0031] Examples of fine aggregates include river sand, mountain sand, land sand, sea sand, silica sand, crushed sand, various slag fine aggregates, various recycled fine aggregates, etc., and may contain fine particles such as clay.

[0032] Examples of coarse aggregate include river gravel, mountain gravel, land gravel, crushed stone, various slag coarse aggregates, lightweight aggregates, and various recycled coarse aggregates.

[0033] In the present invention, as in the above conditions (ii) and (iii), the fine aggregate may contain CO2 fixation modified recycled fine aggregate, and the coarse aggregate may contain CO2 fixation modified recycled coarse aggregate.

[0034] These CO2 fixed modified recycled fine aggregates and CO2 fixed modified recycled coarse aggregates (sometimes collectively referred to as "CO2 fixed modified recycled aggregates") are aggregates produced by reacting CO2 in advance with calcium derived from waste materials such as waste concrete.

[0035] More specifically, CO2-fixed modified recycled fine aggregate includes modified recycled fine aggregate, which is a dry or wet reaction product of carbon dioxide and recycled fine aggregate obtained from hardened concrete and having a water absorption rate of more than 3.0% and not more than 10%, and the modified recycled fine aggregate contains calcium carbonate and silicon dioxide.

[0036] The CO2 fixation and modification recycled fine aggregate can have a particle size of 0.10 to 10 mm, and more preferably, a particle size of 0.10 to 5.0 mm. Furthermore, of those that meet the above particle size range, it is desirable that 85% or more be 5 mm or less. The particle size of this CO2 fixation and modification recycled fine aggregate can be appropriately adjusted by sieving.

[0037] Specifically, the CO2 fixation modified recycled fine aggregate can be produced as follows.

[0038] First, concrete blocks are crushed or grinded to obtain recycled aggregate. There are no particular limitations on the method of crushing or grinding, and known crushing or grinding devices, such as shot-blasting crushers, impact crushers, and mechanical grinding devices that do not require heating, can be used. Particles with a particle size of 10 mm or less are then classified, and particles with a water absorption rate of more than 3.0% and less than 10% are designated as recycled fine aggregate. The water absorption rate can be controlled by the processing method of the crushing or grinding device, such as the number of shot-blasting repetitions. Although the fine aggregate is classified to 10 mm or less, in reality, the fine aggregate is a mixture of multiple sizes. Individual fine aggregates (particles) larger than 10 mm are acceptable as long as their content is 5% by mass or less. Next, the recycled fine aggregate is reacted with carbon dioxide at a volume concentration of 5% or more to obtain a CO2-fixed and modified recycled fine aggregate containing calcium carbonate and silicon dioxide. The reaction between the recycled aggregate and carbon dioxide may be carried out by either a dry method or a wet method. In this way, the CO2 fixation modified recycled fine aggregate can be produced.

[0039] More specifically, the CO2 fixation modified recycled coarse aggregate includes modified recycled coarse aggregate that is a dry or wet reaction product of carbon dioxide and recycled coarse aggregate obtained from hardened concrete and having a water absorption rate of more than 2.0% and not more than 7.0%, and the modified recycled coarse aggregate contains calcium carbonate and silicon dioxide.

[0040] The CO2 fixation and modification recycled coarse aggregate preferably has a particle size of 5.0 to 100 mm, more preferably 5.0 to 60 mm, and particularly preferably 5.0 to 40 mm. Furthermore, of those satisfying the above particle size range, it is desirable that 85% or more be 5.0 mm or larger. This particle size can be adjusted appropriately by sieving.

[0041] CO2 fixation modified recycled coarse aggregate can be produced in the same way as CO2 fixation modified recycled fine aggregate, except that recycled aggregate is classified to particle sizes of 5 mm or more and particles with a water absorption rate of more than 2.0% and 7.0% or less are selected. Note that although the particle size is classified to 5 mm or more as described above, in reality the coarse aggregate is a mixture of multiple sizes, and even if individual particles of coarse aggregate (particles) 5.0 mm or less are present, this is acceptable as long as their content is 10% by mass or less.

[0042] (1-2) Powder: The powder contains a binder, which is a powder having hydraulic and latent hydraulic properties. This powder may contain CO2-fixing fine powder as described in the above condition (i).

[0043] (1-2a) Binder: The binder is a powder having hydraulic properties and latent hydraulic properties. This binder contains, based on its total mass, 5 to 70 mass% of Portland cement (a "hydraulic" powder), 30 to 95 mass% of ground granulated blast furnace slag (a "latent hydraulic" powder), and 0 to 10 mass% of gypsum (a "hydraulic" powder). By including such a binder, the hydraulic composition has fluidity, fluidity retention, and strength development, and furthermore, the carbon dioxide balance can be reduced.

[0044] "Latent hydraulicity" refers to the property that a material does not harden when mixed with water, but begins to harden when an alkaline irritant is also present, and "powder with latent hydraulicity" refers to a powder that exhibits this property.

[0045] Examples of Portland cement include ordinary Portland cement, moderate-heat Portland cement, low-heat Portland cement, high-early-strength Portland cement, and sulfate-resistant Portland cement.

[0046] Examples of gypsum include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum.

[0047] In addition to the Portland cement, ground granulated blast furnace slag, and gypsum, the binder may contain other conventionally known components, such as fly ash, silica fume, stone powder, limestone powder, and an expanding agent.

[0048] Portland cement is contained in the binder at a ratio of 5 to 70 mass %, preferably 5 to 67 mass %, based on the total mass of the binder.

[0049] The ground granulated blast furnace slag is contained in the binder at a ratio of 30 to 95 mass % as described above, and preferably at a ratio of 30 to 92 mass %.

[0050] As described above, the gypsum is contained in a proportion of 0 to 10% by mass, preferably 3 to 8% by mass, based on the total mass of the binder.

[0051] The proportion of the total amount of Portland cement, ground granulated blast furnace slag, and gypsum in the total mass of the binder may be 50 to 100 mass %.

[0052] In the hydraulic composition of the present invention, the mass ratio of water to the binder contained in the powder (water / binder) is preferably 0.3 to 0.9. By setting the mass ratio within this range, the hydraulic composition has fluidity, fluidity retention, and strength development, and further, can reduce the carbon dioxide balance.

[0053] (1-2b) CO2-fixing fine powder: As shown in the above-mentioned condition (i), the powder can contain CO2-fixing fine powder, and by containing this CO2-fixing fine powder, the carbon dioxide balance in the hydraulic composition can be further reduced.

[0054] The CO2-fixed fine powder has a 50% particle size of 100 μm or less and includes recycled concrete powder obtained from hardened concrete and modified concrete powder, which is a reaction product of carbon dioxide and the recycled concrete powder, and this modified concrete powder contains calcium carbonate and silicate.

[0055] This CO2-fixing fine powder can be produced as follows.

[0056] First, concrete blocks are crushed or ground to recover recycled concrete powder with a 50% particle size of 100 μm or less. There are no particular limitations on the method of crushing or grinding, and known crushing or grinding devices, such as shot-blasting crushers, impact crushers, and grinding devices using mechanical grinding without heating, can be used. Next, the recovered recycled concrete powder is reacted with carbon dioxide at a volume concentration of 5% or more to fix CO2 to the cement-derived components contained in the recycled concrete powder. The reaction with carbon dioxide can be carried out either by a dry method in which gaseous carbon dioxide is brought into contact with the recycled concrete powder, or by a wet method in which the recycled concrete powder is immersed in a solution such as water and then carbon dioxide is blown into the liquid (dispersion) to contact the powder. In this way, CO2-fixed fine powder can be produced.

[0057] The 50% particle size of the recycled concrete powder and the CO2 fixed fine powder can be measured as follows.

[0058] First, 0.05 g of recycled concrete powder and CO2-fixed fine powder were ultrasonically dispersed for 180 seconds using ethanol as a solvent. The ultrasonically dispersed material was then measured at room temperature (25°C) using a laser diffraction / scattering particle size distribution analyzer (Microtrac MT3300EXII, manufactured by Microtrac Bell). In this way, the 50% particle size was measured.

[0059] (1-2c) Non-hydraulic powder: The powder may further contain a non-hydraulic powder. This non-hydraulic powder is a powder that does not have hydraulic properties and hardens by reacting with carbon dioxide. Note that "non-hydraulic powder" means "a powder that does not harden, or hardly hardens, even when mixed with water."

[0060] Examples of the non-hydraulic powder include γ-2CaO.SiO2, 3CaO.2SiO2, 3CaO.2SiO2.CaF2, 3CaO.MgO.2SiO2, α-CaO.SiO2, calcium magnesium silicate, etc. Specifically, it can be at least one selected from the group consisting of γ-2CaO.SiO2, 3CaO.2SiO2, α-CaO.SiO2, and calcium magnesium silicate.

[0061] The content of the non-hydraulic powder can be 1 to 100 parts by mass, preferably 5 to 90 parts by mass, and more preferably 10 to 80 parts by mass, per 100 parts by mass of the binder. By setting the content within such a range, the carbon dioxide balance in the hydraulic composition can be reduced.

[0062] (1-3) Compatibilizer: The compatibilizer contains a water-soluble vinyl copolymer having the predetermined structural units 1 to 3.

[0063] By using such a predetermined admixture in a predetermined ratio, even when the above-mentioned conditions (i) to (iii) are satisfied, the obtained hydraulic composition has fluidity, fluidity retention, and strength development, and further, can reduce the carbon dioxide balance.

[0064] In other words, in efforts to realize a carbon-free society, hydraulic composition hardened bodies such as concrete products that incorporate CO2-fixing fine powder or CO2-fixing modified recycled aggregate have been reported. However, the use of CO2-fixing fine powder or CO2-fixing modified recycled aggregate tends to change the physical properties (fluidity, fluidity retention, etc.) of the hydraulic composition, resulting in a decrease in workability. Furthermore, there is a demand for further reductions in carbon dioxide balance. In this situation, the hydraulic composition of the present invention, by incorporating a predetermined admixture in a predetermined ratio, has fluidity, fluidity retention, and strength development properties, and can also reduce the carbon dioxide balance, even when it contains CO2-fixing fine powder or CO2-fixing modified recycled aggregate.

[0065] (1-3-1) Water-soluble vinyl copolymer: The water-soluble vinyl copolymer contains structural unit 1 formed from a compound represented by the following general formula (1), structural unit 2 formed from a compound represented by the following general formula (2), and structural unit 3 formed from other copolymerizable monomers. When the total blending proportions of structural units 1 to 3 is taken as 100% by mass, the copolymer contains structural unit 1 in proportions of 50 to 99% by mass, structural unit 2 in proportions of 1 to 50% by mass, and structural unit 3 in proportions of 0 to 10% by mass. Furthermore, it is preferable that the content of structural unit 1 is 70 to 99% by mass, the content of structural unit 2 is 1 to 30% by mass, and the content of structural unit 3 is 0 to 10% by mass.

[0066] (1-3-1a) Structural Unit 1: Structural unit 1 is a structural unit formed from a compound represented by the following general formula (1).

[0067] (In general formula (1), R 1 , R 2 , R 3 are each independently a hydrogen atom or a methyl group. 4 is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. 5 O is an oxyalkylene group having 2 to 4 carbon atoms (however, when a plurality of oxyalkylene groups are present, one type may be used alone or two or more types may be used). n is R 5 is the average number of moles of O added, and is a number from 1 to 150. x is an integer from 0 to 5. y is an integer of 0 or 1.

[0068] R in general formula (1) 1 , R 2 , R 3 are each independently a hydrogen atom or a methyl group, and among these, R 1 , R 3 is preferably a hydrogen atom.

[0069] (1-3-1b) Structural Unit 2: Structural unit 2 is a structural unit formed from a compound represented by the following general formula (2).

[0070] (In general formula (2), R 6 , R 7, R 8 are each independently a hydrogen atom, a methyl group, or [—(CH) p COOM 2 ] (wherein [-(CH2) p COOM 2 ] is COOM 1 or other COOM 2 In this case, M1 and M2 do not exist in the group. 1 , M 2 are each independently a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2), or an organic amine; and p is an integer of 0 to 2.

[0071] M 1 , M 2 are each independently a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2), or an organic amine, and among these, a hydrogen atom, sodium, and potassium are preferred. Note that since alkaline earth metals are divalent, alkaline earth metals (1 / 2) are 1 or M 2 This indicates that 1 / 2 mole of the compound is added.

[0072] Specific examples of the compound represented by general formula (2) include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, etc., as well as alkali metal salts, alkaline earth metal salts (1 / 2), organic amine salts, etc. Among these, the compound represented by general formula (2) is preferably at least one selected from acrylic acid, methacrylic acid, maleic acid, fumaric acid, and alkali metal salts, alkaline earth metal salts (1 / 2), and organic amine salts thereof.

[0073] (1-3-1c) Structural unit 3: Structural unit 3 is a structural unit formed from another copolymerizable monomer. In other words, it is a structural unit formed from a compound copolymerizable with the compound represented by general formula (1) and the compound represented by general formula (2).

[0074] Examples of compounds that form this structural unit 3 include esters of unsaturated monocarboxylic acids such as (meth)acrylic acid and alcohols having 1 to 30 carbon atoms, amides of the above unsaturated monocarboxylic acids and amines having 1 to 30 carbon atoms, monoesters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid and alcohols having 1 to 30 carbon atoms, diesters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid and alcohols having 1 to 30 carbon atoms, unsaturated sulfonic acids (salts) such as vinyl sulfonate, (meth)allyl sulfonate, and styrene sulfonic acid, vinyl aromatics such as styrene and vinyl toluene, dienes such as butadiene and isoprene, and unsaturated amides such as (meth)acryl(alkyl)amide and N,N-dimethyl(meth)acrylamide.

[0075] The water-soluble vinyl copolymer is not particularly limited in terms of its mass average molecular weight, but the mass average molecular weight can be set to 5,000 to 500,000, preferably 7,500 to 400,000, and more preferably 10,000 to 300,000. By setting the mass average molecular weight within such a range, the hydraulic composition has fluidity, fluidity retention, and strength development, and further, the carbon dioxide balance can be reduced.

[0076] More specifically, the water-soluble vinyl copolymer may be one in which the number n in general formula (1) is 1 to 150, the compound represented by general formula (2) is at least one selected from acrylic acid, methacrylic acid, maleic acid, fumaric acid, and alkali metal salts, alkaline earth metal salts (1 / 2), and organic amine salts thereof, and further, the content of structural unit 1 is 70 to 99 mass%, the content of structural unit 2 is 1 to 30 mass%, and the content of structural unit 3 is 0 to 10 mass%, and the mass average molecular weight is 5,000 to 500,000.

[0077] The water-soluble vinyl copolymer may be used alone or in combination.

[0078] The content (addition amount) of the admixture is preferably 0.02 to 1.0 part by mass per 100 parts by mass of the binder.

[0079] The admixture may contain, in addition to the water-soluble vinyl copolymer, other components than the water-soluble vinyl copolymer, such as a dispersing component such as lignin sulfonate, a retarding component made of an oxycarboxylate such as gluconate or a sugar such as sucrose, a hardening accelerator component, an antifoaming component, an air-entraining component, and an antiseptic component.

[0080] (1-4) Water: There are no particular limitations on the water, so long as it can be used as mixing water for hydraulic compositions (mortar or concrete), and tap water, groundwater, recycled water, etc. can be used as appropriate.

[0081] (1-5) Other Additives: The hydraulic composition of the present invention may further contain other additives as appropriate within the range that does not impair the effects. Examples of such other additives include setting retarders such as sugars and oxycarboxylates, dispersants such as sodium lignin sulfonate, antifoaming agents such as oxyalkylene compounds, hardening accelerators such as alkanolamines, shrinkage reducers such as polyoxyalkylene alkyl ethers, thickeners such as cellulose ether compounds, preservatives such as isothiazolinone compounds, and rust inhibitors such as nitrites.

[0082] The content of the other additives may be, for example, 0 to 10 parts by mass per 100 parts by mass of the binder.

[0083] (2) Hydraulic Composition Hardened Product: The hydraulic composition of the present invention is a raw material for producing a hydraulic composition hardened product such as a concrete product, and the hydraulic composition hardened product can be produced by employing a conventionally known method.

[0084] The hydraulic composition may also contain a non-hydraulic powder, in which case a carbonation curing process may be employed as a process for producing a hardened hydraulic composition. When the hydraulic composition contains a non-hydraulic powder, not only can carbon dioxide be fixed in the carbonation curing process, but also carbon dioxide in the atmosphere can be fixed for a long period of time when the hardened hydraulic composition (concrete product) is installed in a predetermined location.

[0085] When the hydraulic composition contains a non-hydraulic powder, the process for producing a hydraulic composition hardened body can specifically include a curing step of hardening the hydraulic composition of the present invention to obtain a hydraulic composition hardened body, and a curing step (carbonation curing step) of curing the obtained hydraulic composition hardened body in an environment with a CO2 concentration of 5% or more. This production method includes a curing step using the hydraulic composition of the present invention (containing a non-hydraulic powder) and a predetermined curing step, so that the hydraulic composition hardened body has strength development and can further reduce the carbon dioxide balance.

[0086] (2-1) Curing step: The curing step is a step of curing the hydraulic composition of the present invention to obtain a hydraulic composition cured product. As a method for curing the hydraulic composition, a conventionally known method can be appropriately adopted.

[0087] The hydraulic composition of the present invention can be prepared by a conventionally known method.

[0088] (2-2) Curing step (carbonation curing step): In the curing step, particularly when the hydraulic composition contains a non-hydraulic powder, the hardened hydraulic composition obtained in the hardening step can be cured (carbonation curing) in an environment with a CO2 concentration of 5% or more (i.e., a volume concentration of carbon dioxide of 5% or more). In this way, carbon dioxide can be efficiently absorbed and fixed in the hardened hydraulic composition.

[0089] In the above case, the carbon dioxide concentration (CO2 concentration) is not particularly limited as long as it is 5% or more, and can be, for example, 5 to 100%.

[0090] When carbonation curing is performed, if the carbon dioxide concentration (volume concentration) is less than 5%, the amount of carbon dioxide absorbed is too small, and the carbonation curing period until the desired carbon dioxide reduction amount is achieved tends to be prolonged.

[0091] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0092] (Water-soluble vinyl copolymer) The water-soluble vinyl copolymers P-1 to P-13 and rP-1 to rP-2 contained in the admixture are shown in Table 1 below.

[0093]

[0094] In Table 1, the compounds forming the structural units 1 to 3 constituting the water-soluble vinyl copolymers P-1 to P-13 and rP-1 to rP-2 are as follows: X-1: α-methacryloyl-ω-methoxypoly(n=130)oxyethylene X-2: α-methacryloyl-ω-methoxypoly(n=45)oxyethylene X-3: α-methacryloyl-ω-methoxypoly(n=23)oxyethylene X-4: α-methacryloyl-ω-methoxypoly(n=9)oxyethylene X-5: α-methacryloyl-ω-hydroxypoly(n=68)oxyethylene X-6: α-methacryloyl-ω-hydroxy-oxypropylenepoly(n=45)oxyethylene X-7: α-(3-methyl-3-butenyl)-ω-hydroxypoly(n=53)oxyethylene X-8: α-(3-methyl-3-butenyl)-ω-hydroxypoly(n=10)oxyethylene X-9: α-methallyl-ω-hydroxypoly(n=113)oxyethylene X-10: α-allyl-ω-methyl-poly(n=33)oxyethylene X-11: hydroxyethyl acrylate Y-1: methacrylic acid Y-2: acrylic acid Y-3: maleic anhydride Z-1: sodium methallylsulfonate Z-2: methyl acrylate

[0095] The methods for producing the water-soluble vinyl copolymers P-1 to P-13 and rP-1 to rP-2 are described in the following Production Examples 1 to 15.

[0096] (Production Example 1) Synthesis of water-soluble vinyl copolymer P-1: 296.9 g of ion-exchanged water, 324.0 g of α-methacryloyl-ω-methoxypoly(n=130)oxyethylene, 36.0 g of methacrylic acid, and 2.9 g of 3-mercaptopropionic acid were charged into a 1000 mL round-bottom flask equipped with a stirrer, a nitrogen inlet tube, and a dropping funnel. After uniform dissolution with stirring, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was maintained at 65°C in a warm water bath.

[0097] Next, 42.8 g of 3.5% hydrogen peroxide solution was added to the reaction system to initiate the polymerization reaction. The temperature of the reaction system was maintained at 65°C and the polymerization reaction was carried out for 2 hours. Thereafter, 14.3 g of 3.5% hydrogen peroxide solution was further added to the reaction system, and the temperature of the reaction system was maintained at 65°C and the polymerization reaction was carried out for 2 hours.

[0098] A 30% aqueous solution of sodium hydroxide was added to the reaction system to adjust the pH to 7, and the concentration was further adjusted to 40% with ion-exchanged water to obtain a reaction mixture.

[0099] When this reaction mixture was analyzed by gel permeation chromatography (GPC), it was found to have a weight average molecular weight of 65000. This reaction product was designated as water-soluble vinyl copolymer P-1.

[0100] (Production Examples 2 to 9, 14 to 15) Synthesis of Water-Soluble Vinyl Copolymers P-2 to P-9, rP-1 to rP-2: Water-soluble vinyl copolymers P-2 to P-9, rP-1 to rP-2 were synthesized in the same manner as in Production Example 1 above, except that the type and amount of each constituent unit was changed and the amount of 3-mercaptopropionic acid was changed so as to achieve a predetermined mass average molecular weight, as shown in Table 1.

[0101] However, for the water-soluble vinyl copolymer P-5, the concentration was adjusted to 20% with ion-exchanged water after adjusting the pH.

[0102] (Production Example 10) Synthesis of water-soluble vinyl copolymer P-10: 137.3 g of ion-exchanged water and 449.1 g of α-(3-methyl-3-butenyl)-ω-hydroxy-poly(n=53 mol)oxyethylene were charged into a 1000 mL round-bottom flask equipped with a stirrer, a nitrogen inlet tube, and a dropping funnel. After uniform dissolution with stirring, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was maintained at 60°C in a warm water bath.

[0103] Next, 27.6 g of a 3.5% aqueous solution of hydrogen peroxide was added dropwise over 3 hours, and simultaneously, an aqueous solution prepared by uniformly dissolving 31.2 g of acrylic acid in 93.5 g of ion-exchanged water was added dropwise over 3 hours, and simultaneously, an aqueous solution prepared by dissolving 1.6 g of L-ascorbic acid and 3.4 g of 3-mercaptopropionic acid in 45.0 g of ion-exchanged water was added dropwise over 4 hours.

[0104] Thereafter, the temperature of the reaction system was maintained at 60° C. for 2 hours to complete the polymerization reaction. Thereafter, a 30% aqueous solution of sodium hydroxide was added to the reaction system to adjust the pH to 7, and the concentration was adjusted to 50% with ion-exchanged water to obtain a reaction mixture.

[0105] When this reaction mixture was analyzed by gel permeation chromatography (GPC), it was found to have a mass average molecular weight of 71000. This reaction product was designated as water-soluble vinyl copolymer P-10.

[0106] (Production Examples 11 and 12) Synthesis of Water-Soluble Vinyl Copolymers P-11 to P-12: Water-soluble vinyl copolymers P-11 to P-12 were synthesized in the same manner as in Production Example 10 above, except that the type and amount of each constituent unit was changed as shown in Table 1, and the amount of 3-mercaptopropionic acid was changed so as to obtain a predetermined mass average molecular weight.

[0107] (Production Example 13) Synthesis of water-soluble vinyl copolymer P-13: 353.9 g of α-allyl-ω-methyl-poly(n=33)oxyethylene and 35.0 g of maleic anhydride were placed in a 1000 mL round-bottom flask equipped with a stirrer, a nitrogen inlet tube, and a dropping funnel. After uniform dissolution with stirring, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was maintained at 80°C in a warm water bath.

[0108] Next, 7.7 g of azobisisobutyronitrile was added to the reaction system to initiate a radical polymerization reaction. After stirring for 1 hour, 3.8 g of azobisisobutyronitrile was further added to the reaction system, and the radical polymerization reaction was carried out for 4 hours.

[0109] The copolymer thus obtained was hydrolyzed by adding water to obtain a 40% aqueous solution of a water-soluble vinyl copolymer.

[0110] When this reaction mixture was analyzed by gel permeation chromatography (GPC), it was found to have a mass average molecular weight of 29000. This reaction product was designated as water-soluble vinyl copolymer P-13.

[0111] (Weight-average molecular weight) The weight-average molecular weight of each of the water-soluble vinyl copolymers P-1 to P-13 and rP-1 to rP-2 was measured using gel permeation chromatography (GPC) under the following conditions. <Measurement conditions> Apparatus: Shodex GPC-101 (manufactured by Showa Denko K.K.) Column: OHpak SB-806M HQ+SB-806M HQ (manufactured by Showa Denko K.K.) Detector: differential refractometer (RI) Eluent: 50 mM aqueous sodium nitrate solution Flow rate: 0.7 mL / min Column temperature: 40°C Sample concentration: eluent solution with a sample concentration of 0.5% by mass Standards: polyethylene glycol, polyethylene oxide (manufactured by Agilent)

[0112] (Admixtures) Next, the constituent components and content ratios (mass%) of admixtures AD-1 to AD-10 and rAD-1 to rAD-5 are shown in Table 2 below.

[0113]

[0114] In Table 2, the components Q-1 to Q-4 other than the water-soluble vinyl copolymer that make up the admixture are as follows: Q-1: Sodium gluconate (reagent manufactured by Kishida Chemical Co., Ltd.) Q-2: Sucrose (reagent manufactured by Kishida Chemical Co., Ltd.) Q-3: Sodium lignosulfonate (product name: Borresperse NA manufactured by Borregard) Q-4: Melamine-based dispersant (product name: Polfine MF manufactured by Takemoto Oil & Fat Co., Ltd.)

[0115] Preparation of admixtures (AD-1 to AD-10, rAD-1 to rAD-2): Each of the prepared water-soluble vinyl copolymers and the components other than the water-soluble vinyl copolymers were blended in the proportions shown in Table 2 in terms of active ingredient for the types shown in Table 2, and ion-exchanged water was further added. In this way, 20% aqueous solutions of admixtures AD-1 to AD-10 and rAD-1 to rAD-2 were prepared, respectively.

[0116] Preparation of admixtures (rAD-3 to rAD-5): The "components other than the water-soluble vinyl copolymer" shown in Table 2 were mixed in the proportions shown in Table 2, and ion-exchanged water was further added. In this manner, 20% aqueous solutions of admixtures rAD-3 to rAD-5 were prepared, respectively.

[0117] (Examples 1 to 39, Comparative Examples 1 to 20) (1) Hydraulic composition: First, ordinary Portland cement (density 3.16 g / cm 3) was mixed in a forced twin-shaft mixer with a nominal capacity of 50 L under the blending conditions shown in Tables 3 and 4 in a thermostatic chamber at 20°C and 80% humidity. 3 ), or early-strength Portland cement (density 3.14 g / cm 3 ), blast furnace slag ground powder #4000 (density 2.89 g / cm 3 ) or ground granulated blast furnace slag #6000 (density 2.89 g / cm 3 ), anhydrous gypsum or dihydrate gypsum, a non-hydraulic powder carbonate admixture LEAF (manufactured by Denka Co., Ltd., density 3.09 g / cm 3 ), CO2 fixed fine powder (density 2.59g / cm 3 ), CO2 fixation modified recycled fine aggregate (density 2.37 g / cm 3 ), CO2 fixation modified recycled coarse aggregate (density 2.55 g / cm 3 ), fine aggregate (Oi River watershed land sand, density 2.59 g / cm 3 ), coarse aggregate (Okazaki crushed stone, density 2.68 g / cm 3 ) were added in order, and then the mixture was dry mixed for 10 seconds.

[0118] Next, the admixtures shown in Table 2, an air-entraining agent (AE-200 (trade name) manufactured by Takemoto Yushi Co., Ltd.), and an antifoaming agent (AFK-2 (trade name) manufactured by Takemoto Yushi Co., Ltd.) were added to the mixing water. However, the admixtures, air-entraining agent, and antifoaming agent were considered to be part of the mixing water, and the amount of antifoaming agent added was 0.0005 parts by mass per 100 parts by mass of binder. Thereafter, this mixing water was charged into a mixer and mixed for 90 seconds. In this way, 30 L of concrete composition was prepared.

[0119] At this time, the amounts of admixtures and air-entraining agents were adjusted so that the target air content was 4.5%±1.0% and the target slump was 18cm±2.5cm (however, the amount of air-entraining agent added was 0.002 to 0.200 parts by mass per 100 parts by mass of binder). In addition, the temperature of each material was regulated before preparation so that the temperature of the mixed concrete composition would be within the range of 20°C±2°C. The temperature of the mixed concrete composition was measured in accordance with JIS-A1156.

[0120] The CO2 fixation fine powder, CO2 fixation modified recycled fine aggregate, and CO2 fixation modified recycled coarse aggregate were specifically as follows:

[0121] (CO2-fixed fine powder) First, the CO2-fixed fine powder had a 50% particle size of 100 μm or less, and included modified concrete powder, which is a reaction product of recycled concrete powder obtained from hardened concrete and carbon dioxide, and contained calcium carbonate and silicate.

[0122] (Method for producing CO2 fixation fine powder) The concrete blocks were crushed and ground using a known crusher (known crusher such as a shot blast type crusher, an impact crusher, or a grinding device such as a mechanical grinding type that does not involve overheating) to obtain crushed and ground material. After crushing and grinding, a 2 m 3 1.8 t of water and 200 kg of recycled fine powder (recycled concrete powder) obtained by classifying the crushed and ground material into particles with a particle size of 50% 100 μm or less were added to a container and stirred.

[0123] During stirring, carbon dioxide gas was injected into the bottom of the vessel at a rate of 150 L / min. The regenerated fine powder was reacted with carbon dioxide gas until the pH reached 8.6 or less while measuring the pH with a pH meter, thereby obtaining a reaction product containing CO2-fixed fine powder.

[0124] After the reaction, the reaction product containing the CO2-fixed fine powder was removed and excess water was removed using a polypropylene twill filter. The reaction product was then further air-dried to obtain the CO2-fixed fine powder. The twill filter had a thickness of 1.06 mm and an air permeability of 500 cc / cm. 2 / min, vertical strength 300kgf / cm 3 , horizontal 200 kgf / cm3 The following was used.

[0125] (CO2 fixed modified recycled fine aggregate) Next, CO2 fixed modified recycled fine aggregate is particles with a particle diameter of 0.10 mm to 10 mm, of which 85% or more are 5 mm or less, and contains modified recycled aggregate which is a dry or wet reaction product of carbon dioxide and recycled aggregate obtained from hardened concrete having a water absorption rate of more than 3.0% and not more than 10%, calcium carbonate, and silicon dioxide.

[0126] (Method for producing CO2 fixation and modified recycled fine aggregate) Concrete blocks were crushed and ground using a known crusher such as a shot blasting crusher, an impact crusher, or a grinding device using a mechanical grinding method without overheating, to obtain recycled aggregate. After crushing and grinding, a 2m 3 Into a container, 1.8 t of water and 200 kg of recycled aggregate (recycled fine aggregate) classified into particles having a particle size of 10 mm or less were charged and stirred.

[0127] During stirring, carbon dioxide gas was injected into the bottom of the container at a rate of 150 L / min. The recycled fine aggregate was reacted with carbon dioxide gas until the pH reached 8.6 or less while measuring the pH with a pH meter, to obtain a reaction product containing CO2-fixed and modified recycled fine aggregate.

[0128] After the reaction, the reaction product containing the CO2 fixation and modified recycled fine aggregate was taken out and sieved with a nominal mesh size of 0.1 mm to remove excess water. The reaction product was then further air-dried to obtain the CO2 fixation and modified recycled fine aggregate.

[0129] (CO2 fixed modified recycled coarse aggregate) Next, the CO2 fixed modified recycled coarse aggregate is particles with a particle diameter of 5.0 mm to 100 mm, of which 85% or more are 5.0 mm or larger, and contains modified recycled aggregate that is a dry or wet reaction product of carbon dioxide and recycled aggregate obtained from hardened concrete having a water absorption rate of more than 2.0% and not more than 7.0%, calcium carbonate, and silicon dioxide.

[0130] (Method for producing CO2 fixation and modified recycled coarse aggregate) Concrete blocks were crushed and ground using a known crusher such as a shot blasting crusher, an impact crusher, or a grinding device using a mechanical grinding method without overheating, to obtain recycled aggregate. After crushing and grinding, a 2m 3 Into a container, 1.8 t of water and 200 kg of recycled aggregate (recycled coarse aggregate) classified into particles having a particle diameter of 5 mm or more were charged and stirred.

[0131] During stirring, carbon dioxide gas was injected into the bottom of the container at a rate of 150 L / min. The recycled coarse aggregate was reacted with carbon dioxide gas until the pH reached 8.6 or less while measuring the pH with a pH meter, thereby obtaining a reaction product containing CO2-immobilized modified recycled coarse aggregate.

[0132] After the reaction, the reaction product containing the CO2 fixation and modified recycled coarse aggregate was taken out and sieved with a nominal mesh size of 5.0 mm to remove excess water. The reaction product was then further air-dried to obtain the CO2 fixation and modified recycled coarse aggregate.

[0133]

[0134]

[0135] In Tables 3 and 4, pc-1, pc-2, sr-1, sr-2, se-1, and se-2 are as follows: pc-1: ordinary Portland cement pc-2: high-early-strength Portland cement sr-1: fineness of 4100 cm 2 / g of ground granulated blast furnace slag sr-2: fineness of 5900 cm 2 / g of ground granulated blast furnace slag se-1: anhydrous gypsum (manufactured by Fujifilm WAKO Co., Ltd.) se-2: dihydrate gypsum (manufactured by Fujifilm WAKO Co., Ltd.)

[0136] In addition, in Tables 3 and 4, "carbon dioxide emissions derived from materials" was calculated from the CO2 intensity of each material. The CO2 intensity of each material (carbon dioxide emissions derived from materials) is shown in Table 5 below.

[0137]

[0138] Tables 6 and 7 below show the contents (mass%) of cement, ground granulated blast furnace slag, and gypsum in the binder. Tables 6 and 7 also show the content (parts by mass) of CO2-fixing fine powder (content of CO2-fixing fine powder per 100 parts by mass of binder), the content (volume %) of CO2-fixing modified recycled fine aggregate in fine aggregate, and the content (volume %) of CO2-fixing modified recycled coarse aggregate in coarse aggregate.

[0139]

[0140]

[0141] The resulting hydraulic compositions (concrete compositions) were measured for slump (cm), air content, compressive strength (28-day strength), etc., as described below, and evaluated for strength, retention, and CO2 balance reduction rate. The evaluation results are shown in Tables 8 and 9.

[0142] The methods for measuring (calculating) the slump (cm), air content, and compressive strength (28-day strength) are shown below.

[0143] (Slump) The slump was measured in accordance with JIS-A1101 for a concrete composition immediately after mixing and a concrete composition that had been left to stand in a mixing vessel for 30 minutes immediately after mixing.

[0144] (Air Content) The air content of the concrete composition immediately after mixing was measured in accordance with JIS-A1128.

[0145] (Difference in CO2 Balance Reduction Amount) The "difference in CO2 balance reduction amount" was calculated from the difference between the carbon dioxide emission amount derived from the material of each Example and Comparative Example and that of the reference Comparative Example (see Tables 3 and 4).

[0146] In addition, for Examples 1 to 15 and Comparative Examples 1 to 3, the CO2 balance of Comparative Example 4 is used as the reference CO2 balance (amount of carbon dioxide emitted from materials). For Examples 16 to 20 and Comparative Examples 5 to 6, the CO2 balance of Comparative Example 7 is used as the reference CO2 balance. For Examples 21 to 23 and Comparative Examples 8 to 9, the CO2 balance of Comparative Example 10 is used as the reference CO2 balance. For Examples 25 to 30 and Comparative Examples 11 to 13, the CO2 balance of Comparative Example 14 is used as the reference CO2 balance. For Examples 31 to 35 and Comparative Examples 15 to 16, the CO2 balance of Comparative Example 17 is used as the reference CO2 balance. For Examples 36 to 39 and Comparative Examples 18 to 19, the CO2 balance of Comparative Example 20 is used as the reference CO2 balance.

[0147] (Compressive Strength (28-Day Strength)) A cylindrical resin concrete specimen molding form (trade name "Plamold", manufactured by Flolic Co., Ltd., formwork bottom diameter 100 mm, formwork height 200 mm) was prepared, and a concrete composition (hydraulic composition) was filled into the formwork using a two-layer filling method. Thereafter, air curing was performed indoors at 20°C. Two hours after the preparation of the concrete composition, the surface of the concrete composition filled into the formwork was smoothed, and polyethylene wrap was placed over the surface to prevent moisture evaporation, followed by sealed curing until the concrete was aged for 2 days. After sealed curing, the specimen was removed from the formwork and further cured in water at 20°C for 26 days. The poured surface was polished to a smooth surface, yielding a 28-day-old hardened hydraulic composition. The compressive strength of the obtained hardened hydraulic composition was measured as follows.

[0148] The compressive strength (28-day strength) of the test specimens was measured in accordance with JIS-A1108.

[0149] (Strength Ratio) For the measured compressive strengths (28-day strength), the ratio (%) of each compressive strength to the standard strength was calculated using the formula: each compressive strength / standard strength × 100, and this was used as the strength ratio. In Examples 1 to 15 and Comparative Examples 1 to 3, the compressive strength (28-day strength) of Comparative Example 4 was used as the standard strength. In Examples 16 to 20 and Comparative Examples 5 and 6, the compressive strength (28-day strength) of Comparative Example 7 was used as the standard strength. In Examples 21 to 23 and Comparative Examples 8 and 9, the compressive strength (28-day strength) of Comparative Example 10 was used as the standard strength. In Examples 25 to 30 and Comparative Examples 11 to 13, the compressive strength (28-day strength) of Comparative Example 14 was used as the standard strength. In Examples 31 to 35 and Comparative Examples 15 and 16, the compressive strength (28-day strength) of Comparative Example 17 was used as the standard strength. In Examples 36 to 39 and Comparative Examples 18 and 19, the compressive strength (28-day strength) of Comparative Example 20 was used as the standard strength.

[0150] (Strength evaluation) Based on the results of the strength ratio, strength evaluation was performed. The evaluation criteria are as follows. When the slump at 0 minutes was not within the range of 18±2.5 cm even when the amount of admixture added was C×1.00% or more, it was rated as "D" (the same was true for the evaluation of retention). S: When the strength ratio was 103% or more A: When the strength ratio was less than 103% and more than 100% C: When the strength ratio was 100% or less

[0151] (Evaluation of Retention) Evaluation of retention was performed according to the following evaluation criteria. That is, the slump after 30 minutes from immediately after mixing was evaluated according to the following evaluation criteria. S: When the slump after 30 minutes was 15.5 cm or more. C: When the slump after 30 minutes was less than 15.5 cm.

[0152] (Evaluation of CO2 balance reduction rate) The CO2 balance reduction rate was evaluated based on the difference in the amount of CO2 balance reduction, using the following evaluation criteria: S: The difference in the amount of CO2 balance reduction was 25 kg / m 3 A: The difference in CO2 balance reduction is 25 kg / m or more 3 Less than 5 kg / m 3 B: If the difference in CO2 balance reduction amount is 5 kg / m or more 3 Less than 0 kg / m 3 C: If the difference in CO2 balance reduction amount is 0 kg / m3 If:

[0153] In Tables 8 and 9, the amount of admixture added indicates the amount of components in the admixture excluding water.

[0154]

[0155]

[0156] (Results) As shown in Tables 8 and 9, it is understood that the hydraulic compositions of the present examples have fluidity, fluidity retention, and strength development, and furthermore, can reduce the carbon dioxide balance.

[0157] The hydraulic composition of the present invention can be used as a concrete composition, which is a material for concrete and the like.

Claims

1. A hydraulic composition comprising water, at least one aggregate selected from fine aggregate and coarse aggregate, a powder containing the binder described below, and the admixture described below, wherein the powder contains the CO2-fixing fine powder described below, the fine aggregate contains the CO2-fixing modified recycled fine aggregate described below, and the coarse aggregate contains the CO2-fixing modified recycled coarse aggregate described below, wherein the mass ratio of the water to the binder contained in the powder (water / binder) is 0.3 to 0.9, and the content of the admixture is 0.02 to 1.0 part by mass per 100 parts by mass of the binder. Binder: A powder having hydraulic and latent hydraulic properties, containing 5 to 70 mass% Portland cement, 30 to 95 mass% ground granulated blast furnace slag, and 0 to 10 mass% gypsum based on the total mass of the binder. CO2-fixing fine powder: Includes modified concrete powder, which has a 50% particle size of 100 μm or less and is the reaction product of recycled concrete powder obtained from hardened concrete and carbon dioxide, the modified concrete powder containing calcium carbonate and silicates. CO2-fixing modified recycled fine aggregate: Includes modified recycled fine aggregate, which is the dry or wet reaction product of carbon dioxide and recycled fine aggregate obtained from hardened concrete and having a water absorption rate of more than 3.0% and not more than 10%, the modified recycled fine aggregate containing calcium carbonate and silicon dioxide. CO2-fixing modified recycled coarse aggregate: Includes modified recycled coarse aggregate, which is the dry or wet reaction product of carbon dioxide and recycled coarse aggregate obtained from hardened concrete and having a water absorption rate of more than 2.0% and not more than 7.0%, the modified recycled coarse aggregate containing calcium carbonate and silicon dioxide. Admixture: When the total content of structural unit 1 formed from a compound represented by the following general formula (1), structural unit 2 formed from a compound represented by the following general formula (2), and structural unit 3 formed from other copolymerizable monomers is taken as 100 mass%, the admixture comprises a water-soluble vinyl copolymer containing structural unit 1 in an amount of 50 to 99 mass%, structural unit 2 in an amount of 1 to 50 mass%, and structural unit 3 in an amount of 0 to 10 mass%. (In general formula (1), R 1 , R 2 , R 3 are each independently a hydrogen atom or a methyl group. 4 is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. 5 O is an oxyalkylene group having 2 to 4 carbon atoms (however, when a plurality of oxyalkylene groups are present, one type may be used alone or two or more types may be used). n is R 5 is the average number of moles of O added, and is a number from 1 to 150. x is an integer from 0 to 5. y is an integer of 0 or 1. (In general formula (2), R 6 , R 7 , R 8 are each independently a hydrogen atom, a methyl group, or [—(CH) p COOM 2 ] (wherein [-(CH2) p COOM 2 ] is COOM 1 or other COOM 2 In this case, M1 and M2 do not exist in the group. 1 , M 2 are each independently a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2), or an organic amine; and p is an integer of 0 to 2.

2. The hydraulic composition according to claim 1, wherein the powder contains the CO2-fixed fine powder, and the content of the CO2-fixed fine powder is 1 to 100 parts by mass per 100 parts by mass of the binder.

3. The hydraulic composition according to claim 1, wherein the fine aggregate contains the CO2 fixation modified recycled fine aggregate, and the CO2 fixation modified recycled fine aggregate is contained in an amount of 1 to 100 volume % of the total volume of the fine aggregate.

4. The hydraulic composition according to claim 1, wherein the coarse aggregate contains the CO2 fixation modified recycled coarse aggregate, and the CO2 fixation modified recycled coarse aggregate is contained in an amount of 1 to 100 volume % of the total volume of the coarse aggregate.

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