Hydraulic composition, cured object, and method for producing cured object

Abstract

This hydraulic composition contains a hydraulic material and a curing accelerator, and does not contain cement. The hydraulic material contains blast furnace slag powder. The curing accelerator is composed of only an inorganic peroxide, and does not contain an alkali stimulant other than the inorganic peroxide.

Description

Hydraulic composition, cured product, method for producing cured product

[0001] The present invention relates to a hydraulic composition, a hardened product, and a method for producing the hardened product.

[0002] For example, Patent Document 1 discloses a method for manufacturing a concrete block, which comprises the steps of pouring a concrete material containing a binder and aggregate, wherein the binder contains 30% by weight or more of ground granulated blast furnace slag, to form a concrete block, applying a design to the surface of the concrete block, and oxidizing the designed surface of the concrete block.

[0003] Japanese Patent Application Publication No. 2009-91207

[0004] Hydraulic compositions using blast furnace slag powder as a part of the hydraulic material and their hardened products are known. However, it is known that hardened products of hydraulic compositions using blast furnace slag powder develop a blue color immediately after curing.

[0005] Although the blue color of such a hardened product fades over time, it may take several months for the color to fade. Furthermore, since hardened products are often stored in stacks, the blue color may not fade even after several months on surfaces that are less exposed to the air. For this reason, when concrete blocks or the like are manufactured as hardened products of hydraulic compositions, they must wait until the blue color has sufficiently faded before shipping, which significantly hinders the inspection and shipping of concrete blocks. Therefore, in the past, treatments such as those for fading the blue color of hardened products have been performed.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic composition containing blast furnace slag powder that can reduce the blue color that occurs immediately after curing when made into a hardened body.

[0007] The hydraulic composition of the present disclosure contains a hydraulic material and a hardening accelerator, but does not contain cement, the hydraulic material contains blast furnace slag powder, and the hardening accelerator is composed only of inorganic peroxides, and does not contain any alkaline activators other than the inorganic peroxides.

[0008] The present invention can provide a hydraulic composition containing blast furnace slag powder that can reduce the blue color that appears immediately after curing when made into a hardened body.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention. [Hydraulic Composition] The hydraulic composition of this embodiment contains a hydraulic material and a hardening accelerator. The hydraulic material contains blast furnace slag powder. The hardening accelerator contains an inorganic peroxide.

[0010] In this specification, the term "hydraulic composition" refers to a composition that hardens through a chemical reaction when mixed with water. The hydraulic composition may be a mixture of solid powders or the like that does not contain water, and may also contain water as described below. When it is necessary to distinguish between a hydraulic composition that does not contain water and a hydraulic composition that contains water, the hydraulic composition that does not contain water may be referred to as "hydraulic powder." The hydraulic composition that contains water may be referred to as "water-containing hydraulic composition," and when the water content is particularly high and the fluidity is high, it may be referred to as "hydraulic slurry." (1) Components Contained in the Hydraulic Composition The components contained in the hydraulic composition of this embodiment are described below. (1-1) Hydraulic Material The hydraulic composition of this embodiment may contain a hydraulic material.

[0011] The hydraulic material means a material that hardens when water is added or when an alkaline stimulus or the like is further added.

[0012] The hydraulic material may include blast furnace slag powder.

[0013] Blast furnace slag powder is a by-product obtained during the production of pig iron in a blast furnace. It is ground slag obtained by the reaction of non-iron components contained in iron ore, limestone as an auxiliary material, and ash from coke in the blast furnace used to produce pig iron.

[0014] Blast furnace slag powder has latent hydraulic properties, which means that it hardens when exposed to alkaline stimulation. Since blast furnace slag powder is a by-product of steelmaking, the carbon dioxide emissions during its production are counted as part of the steelmaking process. Therefore, the hydraulic composition of this embodiment containing blast furnace slag powder can reduce carbon dioxide emissions and can be said to be a material with a low environmental impact.

[0015] The blast furnace slag powder is not particularly limited, but from the viewpoint of increasing the initial strength of the hardened body of the hydraulic composition, it is preferable that the Blaine value is high, for example, 3000 Blaine or more is preferable, and 4000 Blaine or more is more preferable.

[0016] There is no particular upper limit to the Blaine value of the blast furnace slag powder, but a Blaine value of 8000 or less is preferable because a high Blaine value tends to make the powder less easy to handle, such as by adhering to the inside of a storage silo.

[0017] Therefore, for example, a material having a Blaine value of 3000 to 8000 can be used as the blast furnace slag powder, and may have a Blaine value of 4000 to 8000. When the Blaine value is within the above range, the blast furnace slag powder becomes a fine powder with a small particle size, and therefore the blast furnace slag powder may be referred to as ground blast furnace slag powder.

[0018] The Blaine value of the above-mentioned blast furnace slag powder refers to the Blaine value that is added when indicating the type (quality) of ground granulated blast furnace slag, such as ground granulated blast furnace slag 3000, in the standard for ground granulated blast furnace slag for concrete, JIS A 6206 (2013).

[0019] In the above JIS standard, in the case of ground granulated blast furnace slag 3000 (Blaine value 3000), the specific Blaine specific surface area is 2750 cm ２ / g or more 3500cm ２ / g or less.

[0020] In the case of ground granulated blast furnace slag 4000 (Blaine value 4000), the specific Blaine specific surface area is 3500 cm ２ / g or more 5000cm ２ / g or less.

[0021] In the case of ground granulated blast furnace slag 6000 (Blaine value 6000), the specific Blaine specific surface area is 5000 cm ２ / g or more 7000cm ２ / g or less.

[0022] In the case of ground granulated blast furnace slag 8000 (Blaine value 8000), the specific Blaine specific surface area is 7000 cm ２ / g or more 10000cm ２ / g or less.

[0023] Therefore, blast furnace slag powder with a Blaine specific surface area of ​​3000 to 8000 is 2750 cm ２ / g or more 10000cm ２ / g. In addition, the blast furnace slag powder of 4000 Blaine or more and 8000 Blaine or less means that the Blaine specific surface area is 3500 cm ２ / g or more 10000cm ２ This means that the solubility is less than 1 / g.

[0024] The specific Blaine specific surface area can be evaluated according to JIS R 5201 (2015). The Blaine specific surface area in this specification means the specific surface area evaluated using a Blaine air permeation device as described in JIS R 5201 (2015).

[0025] The hydraulic material of the hydraulic composition of this embodiment may be composed of blast furnace slag powder alone, or may further contain other components.

[0026] The hydraulic composition of this embodiment may contain fly ash or limestone powder as a hydraulic material in addition to the blast furnace slag powder. When the hydraulic composition of this embodiment contains a component other than the blast furnace slag powder as a hydraulic material, the content thereof is preferably 0 to 30 parts by mass, based on 100 parts by mass of the blast furnace slag powder. When the hydraulic composition of this embodiment contains multiple types of components other than the blast furnace slag powder as hydraulic materials, the total amount thereof preferably satisfies the above range.

[0027] The blending ratio of the hydraulic material in the hydraulic composition of this embodiment is not particularly limited, and can be selected depending on the strength required for the hydraulic composition of this embodiment.

[0028] The unit hydraulic material-hardening accelerator amount, which is the total unit amount of the hydraulic material and the hardening accelerator described later contained in the hydraulic composition of this embodiment, is 200 kg / m ３ More than 800kg / m ３ or less, 250 kg / m ３ More than 800kg / m ３ It may be the following:

[0029] For example, the unit amount of hydraulic material-hardening accelerator is 200 kg / m ３ More than 600kg / m ３ It may be less than 200 kg / m ３ More than 550kg / m ３ The unit amount of hydraulic material-hardening accelerator may be less than 200 kg / m ３ More than 600kg / m ３ By satisfying the following conditions, it is possible to at least satisfy the compressive strength classification A (08) for basic blocks of JIS A 5406 (2023).

[0030] In particular, when high strength is required for the hardened product of the hydraulic composition of this embodiment, the unit hydraulic material-hardening accelerator amount is 550 kg / m ３ More than 800kg / m ３ It may be the following:

[0031] The term "unit amount" refers to the mass of the target material contained per unit volume of a kneaded hydraulic composition containing water, prepared during the process of producing a hardened body, for example, in the kneading step described below. Therefore, the unit amount of hydraulic material-hardening accelerator refers to the total mass of the hydraulic material and hardening accelerator contained per unit volume of a kneaded hydraulic composition containing water. (1-2) Hardening Accelerator (1-2-1) About Hardening Accelerator Blast furnace slag powder has latent hydraulicity, which means that it hardens when exposed to alkaline stimulation. Furthermore, a hardening accelerator is a material that imparts alkaline stimulation to the blast furnace slag powder when mixed with water. Therefore, a hardening accelerator is a material that can impart alkaline stimulation to the blast furnace slag powder when mixed with water. (Inorganic Peroxide) The higher the content of blast furnace slag powder in the hydraulic composition, and the more accelerated curing using steam is performed after molding the hydraulic composition, the more likely the hardened body of the hydraulic composition will have a stronger blue color immediately after curing. This is thought to be because the sulfur component contained in the blast furnace slag powder forms sulfur salts, which then develop a color, resulting in the blue color.

[0032] Although the blue color of such a hardened product fades over time, it may take several months for the color to fade. Furthermore, since hardened products are often stored in stacks, the blue color may not fade even after several months on surfaces that are less exposed to the outside air. For this reason, when concrete blocks or the like are manufactured as hardened products of hydraulic compositions, they must be shipped until the blue color has sufficiently faded, which causes significant problems in the inspection and shipping of concrete blocks.

[0033] Therefore, the inventors of the present invention conducted research and found that when a curing accelerator contains an inorganic peroxide, the blue color of the cured product can be reduced. The curing accelerator may be composed only of an inorganic peroxide, or may contain an inorganic peroxide and further other components, as described below.

[0034] The mechanism by which the inclusion of an inorganic peroxide in the hardening accelerator reduces the blue color of the hardened body immediately after curing is presumed to be as follows.

[0035] When inorganic peroxides react with water, they produce hydroxide salts and hydrogen peroxide.

[0036] When the inorganic peroxide is calcium peroxide, calcium peroxide and water react according to the chemical formula shown in the following formula (1) to produce calcium hydroxide and hydrogen peroxide.

[0037] CaO ２ +2H ２ O → Ca(OH) ２ +H ２ O ２ (1) Since hydrogen peroxide functions as an oxidizing agent, it is believed that when the hydraulic composition contains inorganic peroxide, the sulfur components contained in the blast furnace slag powder are oxidized, thereby reducing the blue color of the hardened hydraulic composition immediately after curing.

[0038] As described above, when inorganic peroxides react with water, they produce hydroxide salts in addition to hydrogen peroxide. The hydroxide salts dissolve in water and exhibit alkaline properties, which provide alkaline stimulation to the blast furnace slag powder and also function as a hardening accelerator.

[0039] The inorganic peroxide is not particularly limited, but is preferably an inorganic peroxide containing one or more elements selected from alkali metal elements and alkaline earth metal elements. The hydraulic composition of this embodiment may also contain multiple types of inorganic peroxides containing different elements.

[0040] In this specification, examples of alkali metal elements include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).

[0041] In this specification, alkaline earth metal elements refer to alkaline earth metal elements in a broad sense, such as beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

[0042] Inorganic peroxides include lithium peroxide (Li ２O ２ ), sodium peroxide (Na ２ O ２ ), potassium peroxide (K ２ O ２ ), magnesium peroxide (MgO ２ ), calcium peroxide (CaO ２ ), barium peroxide (BaO ２ In particular, it is preferable that the inorganic peroxide contains one or more selected from calcium peroxide and magnesium peroxide, because this is low cost and easy to handle, and the inorganic peroxide may consist of only one or more selected from calcium peroxide and magnesium peroxide.

[0043] In particular, the inorganic peroxide preferably contains calcium peroxide because of its low cost and easy availability, and the inorganic peroxide may consist solely of calcium peroxide.

[0044] The inorganic peroxide may be used as a powder or may be formed into granules (pellets). By using the inorganic peroxide as a powder, the dispersibility of the inorganic peroxide can be improved when preparing a hydraulic composition. By forming the inorganic peroxide into a molded body such as granules, the workability of operations such as measuring can be improved.

[0045] To improve handleability, inorganic peroxides may be mixed with other bulking agents to form a mixture. When mixed with other bulking agents to form a mixture, the concentration of the inorganic peroxide contained in the mixture is not particularly limited, but can be, for example, 10% by mass or more and 35% by mass or less. By setting the concentration of the inorganic peroxide in the mixture to 10% by mass or more, the concentration of the inorganic peroxide in the mixture can be sufficiently high, thereby reducing the amount of the mixture added when preparing a hydraulic composition. Furthermore, by setting the concentration of the inorganic peroxide in the mixture to 35% by mass or less, the reactivity of the inorganic peroxide in the mixture can be adjusted and stabilized, thereby improving handleability. When a mixture contains multiple types of inorganic peroxides, it is preferable that the total concentration of the inorganic peroxides satisfy the above range. Furthermore, the mixture may be used as a powder as described above, or may be used as a molded product such as granules. (Alkaline stimulant) The curing accelerator may further contain an alkaline stimulant.

[0046] As the alkaline stimulant, any material other than inorganic peroxides that can impart alkaline stimuli to hydraulic materials when mixed with water can be used.

[0047] The alkaline irritant may preferably be one or more selected from hydroxides and carbonates, and preferably contains one or more elements selected from alkali metal elements and alkaline earth metal elements.

[0048] Therefore, the alkali activator may contain one or more elements selected from alkali metal elements and alkaline earth metal elements, and may be one or more salts selected from hydroxides and carbonates. Since the alkali metal elements and alkaline earth metal elements have already been explained, their explanation will be omitted. The hydraulic composition of this embodiment may also contain multiple types of alkali activators containing different elements and salts.

[0049] Examples of alkaline stimulants include calcium hydroxide (Ca(OH) ２ ), sodium hydroxide (NaOH), potassium hydroxide (KOH), potassium carbonate (K ２ CO ３), sodium carbonate (Na ２ CO ３ ) can be more preferably used.

[0050] From the viewpoint of increasing the strength of the set body of the hydraulic composition of this embodiment, the alkaline activator is more preferably one or more selected from sodium carbonate (soda ash) and calcium hydroxide.

[0051] The curing accelerator may be composed of only inorganic peroxide and may not contain an alkaline stimulant, however, since alkaline stimulants such as sodium carbonate are less expensive and more readily available than inorganic peroxides, it is preferred that the curing accelerator be a mixture of inorganic peroxide and alkaline stimulant.

[0052] However, when the ratio of the alkali stimulant contained in the hardening accelerator is high, the blue color of the cured body of the hydraulic composition may become relatively stronger compared to when the ratio of the alkali stimulant contained in the hardening accelerator is low. Also, when the ratio of the alkali stimulant contained in the hardening accelerator is high, efflorescence, which is a white precipitate, is more likely to occur on the surface of the molded body or the hardened body compared to when the ratio of the alkali stimulant contained in the hardening accelerator is low.

[0053] Efflorescence in concrete, which is a hardened product of general cement, is formed when alkaline lye contained in the cement components precipitates on the surface of the concrete, etc. Therefore, the main component of efflorescence in general concrete is calcium carbonate (CaCO ３ ), which is formed when calcium oxide (CaO), the main component of cement, reacts with water and carbon dioxide gas to precipitate.

[0054] In the course of the inventors' research into hydraulic compositions, they found that when hydraulic compositions were prepared using sodium carbonate as an alkaline stimulant without adding inorganic peroxides or cement components as hardening accelerators, efflorescence sometimes precipitated on the surface of the molded or hardened concrete. That is, while the efflorescence in ordinary concrete is mainly composed of calcium carbonate, white precipitates were sometimes observed even though no calcium component was added.

[0055] Therefore, a qualitative analysis of the elements contained in the precipitated efflorescence was performed using an X-ray microanalyzer, and the main elements were found to be oxygen, sodium, sulfur, and carbon. This indicated that the observed efflorescence contained sodium carbonate, which was added as an alkaline irritant, as its main component. It was also confirmed that the amount of efflorescence generated was reduced by adding inorganic peroxide as a hardening accelerator in addition to the alkaline irritant.

[0056] As described above, the curing accelerator contains an inorganic peroxide, which can reduce the occurrence of efflorescence in molded products and cured products. Furthermore, increasing the proportion of inorganic peroxide in the curing accelerator can particularly reduce the occurrence of efflorescence. Therefore, the mixing ratio of the inorganic peroxide and the alkaline irritant in the curing accelerator can be selected depending on the degree of efflorescence reduction required for the cured product, the degree of blue color, etc. For example, the proportion of the inorganic peroxide in the curing accelerator, based on the total amount of the inorganic peroxide and the alkaline irritant, may be 1% by mass or more and 100% by mass or less, 2% by mass or more and 80% by mass or less, 5% by mass or more and 50% by mass or less, or 5% by mass or more and 30% by mass or less.

[0057] The hydraulic composition of this embodiment preferably does not contain various cements that have conventionally been used as alkaline activators in hydraulic compositions using blast furnace slag powder, etc. Although cement may also function as a hydraulic material, it is preferable that the hydraulic composition of this embodiment does not contain various cements regardless of their function.

[0058] In the manufacturing process of cement, limestone (CaCO ) is used to produce calcium oxide (CaO), which is the main component. ３ ) is fired at a high temperature to decarbonate. Therefore, a large amount of carbon dioxide is emitted during the manufacturing process of cement, and the hydraulic composition of this embodiment does not contain various cements, so that the amount of carbon dioxide emitted during the manufacturing process can be reduced, making it possible to make a material with a low environmental impact.

[0059] The fact that the hydraulic composition of this embodiment does not contain various cements can also be rephrased as, for example, not containing ground clinker.

[0060] Here, the hydraulic composition of this embodiment does not contain various cements, i.e., does not contain ground clinker, means that they are not intentionally added, and does not exclude the possibility of them being mixed in as an inevitable impurity during the manufacturing process, etc. In the hydraulic composition of this embodiment, the content of ground clinker can be 1% by mass or less, taking into account the contamination of inevitable impurities, for example. (1-2-2) Content of Hardening Accelerator The content of the hardening accelerator in the hydraulic composition of this embodiment is not particularly limited and can be selected depending on the strength required of the hydraulic composition, etc. For example, the hydraulic composition of this embodiment preferably contains 3 to 25 parts by mass of hardening accelerator per 100 parts by mass of hydraulic material, and more preferably 3 to 20 parts by mass of hardening accelerator. Note that the hydraulic material may be composed solely of blast furnace slag powder, or may contain fly ash or limestone in addition to blast furnace slag powder.

[0061] The hydraulic composition of this embodiment contains 3 parts by mass or more of a hardening accelerator per 100 parts by mass of hydraulic material, thereby increasing the strength of the set body. Although increasing the ratio of hardening accelerator to hydraulic material also increases the strength of the set body, the degree of increase in strength of the set body saturates at a ratio of about 25 parts by mass of hardening accelerator per 100 parts by mass of hydraulic material. Therefore, the hydraulic composition of this embodiment preferably contains 25 parts by mass or less of a hardening accelerator per 100 parts by mass of hydraulic material. (1-3) Other Additive Components The hydraulic composition of this embodiment may further contain other additive components. (1-3-1) Water The hydraulic composition of this embodiment may further contain water.

[0062] The amount of water contained in the hydraulic composition of this embodiment is not particularly limited, and can be selected depending on the fluidity required for the hydraulic composition, the strength required for the set product, and the like.

[0063] The hydraulic composition of this embodiment can be molded using a mold, for example, and used as a concrete block or the like. By forming a hard-mix hydraulic composition with zero slump, it becomes possible to immediately demold the composition after filling it into a mold. That is, by forming a hydraulic composition with zero slump, it becomes possible to maintain the molded shape even after immediate demolding, and the time left after filling it into a mold can be shortened, thereby increasing productivity.

[0064] Therefore, the hydraulic composition of this embodiment has a unit water amount of 130 L / m ３ The hydraulic composition of this embodiment may have a unit water amount of 130 L / m or less. ３ By setting the temperature below, zero slump can be achieved, and productivity of hardened products such as concrete blocks can be improved.

[0065] The lower limit of the unit water content of the hydraulic composition of this embodiment is not particularly limited, but is, for example, 60 L / m ３ It can do more than that.

[0066] For example, in order to perform pour molding, the unit water amount of the hydraulic composition of this embodiment is set to 130 L / m ３ In this case, the upper limit of the unit water content of the hydraulic composition of the present embodiment is not particularly limited, but may be, for example, 500 L / m ３ Therefore, the hydraulic composition of this embodiment may have a unit water amount of 130 L / m or less. ３ More than 500 L / m ３ The following may also be used.

[0067] The unit water content means the amount of water per unit volume of a kneaded product of a water-containing hydraulic composition prepared in the process of producing a hardened body, for example, in the kneading step described below. The density of water is 1 g / cm ３ So, L / m ３ is kg / m ３ (1-3-2) Aggregate The hydraulic composition of this embodiment may also contain aggregate.

[0068] The aggregate may be one or more selected from sand, gravel, crushed sand, crushed stone, various slags, etc. The sand may be a natural aggregate such as river sand, etc. The crushed stone may be crushed rocks or boulders.

[0069] (1-3-3) Other Additives The hydraulic composition of this embodiment may contain, in addition to the above materials, admixtures such as air-enhancing agents and water-reducing agents, and colorants such as chromium oxide, iron oxide, red iron oxide, titanium oxide, etc. [Hardened Product] The hardened product of this embodiment may be a hardened product of the hydraulic composition according to one aspect of the present disclosure.

[0070] The hydraulic composition described above contains a hydraulic material and a hardening accelerator, the hydraulic material containing blast furnace slag powder, and the hardening accelerator containing an inorganic peroxide. Therefore, the hardened body of this embodiment can reduce the blue color and suppress the occurrence of efflorescence even immediately after curing.

[0071] Furthermore, the cured product of this embodiment can reduce carbon dioxide emissions during production, resulting in a cured product with low environmental impact.

[0072] The hardened product of this embodiment may be a molded product obtained by molding the hydraulic composition according to one aspect of the present disclosure into a predetermined shape. Examples of the hardened product of this embodiment include concrete blocks, and may be one or more types selected from, for example, concrete blocks for construction such as hollow blocks and formwork blocks, and concrete blocks for paving such as interlocking blocks. Although the term "concrete block" is used because of the use of commonly used trade names, the hydraulic composition according to one aspect of the present disclosure preferably does not contain cement, and therefore the concrete block, which is its hardened product, preferably also does not contain a cement component.

[0073] The hardened body of this embodiment can reduce the blue color on the surface immediately after curing, for example, within 7 days after the end of curing, or within 7 days after the end of a curing process such as an accelerated curing process. For example, compared with a case in which the hardening accelerator contained in the hydraulic composition used in the hardened body of this embodiment does not contain an inorganic peroxide and contains only an alkaline irritant, ＊ a ＊ b ＊b in color space (JIS Z 8781-4 (2013)) ＊ The color can be compared between a set product using a hydraulic composition in which the inorganic peroxide is replaced with the same mass of an alkali irritant, for example. The color may also be compared between a set product using a hydraulic composition containing only an alkali irritant, but no inorganic peroxide as a hardening accelerator, and the same unit amounts of other components.

[0074] The hardened body of this embodiment may be, for example, L ＊ a ＊ b ＊ b in color space ＊ can also be greater than 0. [Method for Producing a Hardened Body] The method for producing a hardened body of this embodiment can include the following kneading step, molding step, and demolding step. Note that the method for producing a hardened body of this embodiment can produce a hardened body according to one aspect of the present disclosure, and a hydraulic composition can also be produced in the process, so some of the details already explained will be omitted. Each step will be explained below. (1) Kneading Step In the kneading step, a hydraulic material, a hardening accelerator, and water are kneaded to form a hydraulic composition. The hydraulic material can contain blast furnace slag powder. The hardening accelerator can also contain an inorganic peroxide.

[0075] In the kneading step, components that can be contained in the hydraulic composition can be kneaded. Each component has already been explained, so explanation will be omitted. Note that, since water is also added in the kneading step, a water-containing hydraulic composition, which is a hydraulic composition containing water, is obtained.

[0076] The unit water amount of the hydraulic composition obtained in the kneading step is not particularly limited, but is, for example, 130 L / m ３ The unit water volume may be 130 L / m or less. ３ By doing so, zero slump can be achieved and immediate demolding can be performed in the molding process, thereby increasing the productivity of concrete blocks, etc.

[0077] In addition, when pouring, the unit water volume is 130 L / m ３ More than 500 L / m ３The following may be adopted: (2) Molding Step In the molding step, the hydraulic composition is filled into a mold to form a molded body.

[0078] The mold used in the molding step is not particularly limited, and can have a shape that matches the concrete block to be manufactured, etc. (3) Demolding Step In the demolding step, the molded body can be demolded from the mold.

[0079] The timing of demolding is not particularly limited, but the molded body can be demolded at a timing depending on the fluidity of the hydraulic composition constituting the molded body, etc., so that the demolded molded body can maintain the desired shape.

[0080] For example, if the unit water content of the hydraulic composition obtained in the kneading step is sufficiently small, the demolding step can be carried out immediately after the molding step. In other words, immediate demolding can be carried out. By enabling immediate demolding, the productivity of the hardened body can be increased. (4) Other Steps The method for producing a hardened body of this embodiment can also have any further steps. (4-1) Curing Step The method for producing a hardened body of this embodiment can also have a curing step of curing the molded body after the demolding step.

[0081] The conditions for the curing step are not particularly limited, but for example, steam curing can be performed using a steam curing facility in an environment of, for example, 40°C or higher.

[0082] The upper limit of the temperature during steam curing in the curing step is not particularly limited, but can be, for example, 65° C. or lower. The duration of steam curing is not particularly limited, but, for example, the duration of heating to achieve the above temperature range may be 2 hours or more and 12 hours or less.

[0083] In the curing step, curing can also be performed using an autoclave, in which case curing can be performed by maintaining a temperature of 180° C. to 190° C. and a pressure of 10 atm to 11 atm for approximately 3 hours to 5 hours. When curing is performed using an autoclave, it is preferable to perform curing under isothermal and isobaric conditions in which the temperature and pressure are maintained after the above temperature and pressure are reached.

[0084] Accelerated curing of the compact can improve the initial strength of the hardened body even if the hydraulic material contains a large amount of blast furnace slag powder. Curing using an autoclave, in particular, can reduce the occurrence of efflorescence.

[0085] The present invention will be described below with reference to specific examples, but is not limited to these examples. (Evaluation Method) (1) Compressive Strength The compressive strength was evaluated according to the compressive strength test method specified in Appendix B of JIS A 5406 (2023).

[0086] The measurements were carried out after the curing process. (2) Color evaluation After the curing process, at least one surface of the hardened body was immersed in water for 7 days, and then the color of the surface of the hardened body was measured using a colorimeter (manufactured by Minolta, model: CR-310). [Experimental Example 1] [Example 1-1] A hydraulic composition and a hardened body were produced according to the following procedure.

[0087] The raw materials were weighed to obtain the ratios shown in Table 1 and kneaded to prepare hydraulic compositions (kneading step). The blast furnace slag powder used was ground blast furnace slag 4000 as specified in JIS A 6206 (2013), and the specific evaluation value of the Blaine specific surface area was 4720 cm. ２ In the other examples and comparative examples below, the same blast furnace slag powder is used as the blast furnace slag powder indicated as "Blast furnace slag powder 4000 Blaine" in the recipe.

[0088] Next, the obtained hydraulic composition was filled into a mold to form a molded body (molding step).

[0089] The molded body was demolded from the mold (demolding step). The demolding step was immediate demolding, which was carried out immediately after the molding step.

[0090] After the demolding step, the molded body was steam cured in an environment of 65° C. After the steam curing, natural curing was also carried out for an additional 7 days (curing step). That is, the hardened body after 7 days of steam curing was evaluated as follows.

[0091] The obtained hardened body was evaluated as described above. The evaluation results are shown in Table 2. [Comparative Example 1-1] Raw materials were weighed out so as to obtain the ratios shown in Table 1 and kneaded to prepare a hydraulic composition (kneading step). In Comparative Example 1-1, calcium peroxide, which is an inorganic peroxide, was not added as a hardening accelerator, and calcium peroxide was replaced with soda ash, which is sodium carbonate.

[0092] A molded body and a hardened body were produced under the same conditions as in Example 1-1 except for the above points, and were evaluated. The evaluation results are shown in Table 2. [Example 1-2] Raw materials were weighed out to obtain the ratios shown in Table 1 and kneaded to prepare hydraulic compositions (kneading step). In Example 1-2, a black pigment was further added so that the occurrence of efflorescence could be confirmed.

[0093] Aside from the above, a molded body and a hardened body were produced under the same conditions as in Example 1-1, and evaluations were carried out. The evaluation results are shown in Table 2. [Comparative Example 1-2] Raw materials were weighed out to obtain the ratios shown in Table 1 and kneaded to prepare a hydraulic composition (kneading step). In Comparative Example 1-2, calcium peroxide, which is an inorganic peroxide, was not added as a hardening accelerator, and calcium peroxide was replaced with soda ash.

[0094] Except for the above points, molded bodies and hardened bodies were produced and evaluated under the same conditions as in Example 1-2. The evaluation results are shown in Table 2. [Examples 1-3 to 1-5] Raw materials were weighed out so as to obtain the ratios shown in Table 1 and kneaded to prepare hydraulic compositions (kneading step).

[0095] In Example 1-3, no alkaline stimulant was used as the hardening accelerator, and only calcium peroxide, an inorganic peroxide, was added. The unit amount of the hardening accelerator was set to the same value as in Example 1-1.

[0096] In Example 1-4, no alkaline stimulant was used as the hardening accelerator, and only calcium peroxide, an inorganic peroxide, was added. In this case, more inorganic peroxide was added than in Example 1-3 so that the unit amount of inorganic peroxide would be the value shown in Table 1.

[0097] In Examples 1-5, no alkaline irritant was used as the hardening accelerator, and only calcium peroxide, an inorganic peroxide, was added. In this case, the calcium peroxide was mixed with a bulking agent to make the calcium peroxide concentration 35% by mass, which improved handling. By keeping the calcium peroxide at 35% by mass or less, it is no longer subject to the classification of hazardous materials under the Fire Service Act. The inorganic peroxide was added so that the unit amount mixed with the bulking agent was the value shown in Table 1.

[0098] Therefore, in Table 1, the unit amount of inorganic peroxide (calcium peroxide) is 110 kg / m ３ However, the unit amount of calcium peroxide excluding the bulking agent is 38.5 kg / m ３ becomes.

[0099] Except for the above points, molded articles and cured articles were produced under the same conditions as in Example 1-1, and evaluations were carried out. The evaluation results are shown in Table 2.

[0100]

[0101] According to the results shown in Table 2, the compressive strength was 16 N / mm in both Examples 1-1 and 1-2. ２ It was confirmed that the specimens had high compressive strength.

[0102] For Examples 1-3, the compressive strength was 16 N / mm ２ Although the compressive strength was below 16 N / mm in Examples 1-4 and 1-5, in which the amount of inorganic peroxide added was increased, ２ It was confirmed that it exceeds

[0103] According to the results shown in Table 2, in Examples 1-1 and 1-2 in which calcium peroxide was added as a hardening accelerator, the hardening rate was higher than that of the corresponding Comparative Examples 1-1 and 1-2. ＊ It was confirmed that the value of b increased and the blue hue was reduced. ＊ It was confirmed that the value was greater than 0.

[0104] For Example 1-3, the b ＊It was confirmed that the value of b increased and the blue hue was reduced. ＊ It was confirmed that the value was greater than 0.

[0105] In Examples 1-4 and 1-5, in which the amount of inorganic peroxide added was further increased compared to Example 1-3, the ＊ It was confirmed that the value of b increased and the blue hue was reduced. ＊ It was confirmed that the value was greater than 0.

[0106] In addition, when Example 1-2 in which a black pigment was added was compared with Comparative Example 1-2, Comparative Example 1-2 had a higher L ＊ It was confirmed that the occurrence of efflorescence was reduced in Example 1-2. Note that, since Examples 1-1, 1-3, 1-4, and 1-5 and Comparative Example 1 were not colored black, the L ＊ The occurrence of efflorescence cannot be determined from the brightness. [Experimental Example 2] In Experimental Example 2, the cases where magnesium peroxide was used as the inorganic peroxide and where calcium hydroxide was used as the alkaline irritant were examined. [Example 2-1] A hydraulic composition and a hardened body were produced according to the following procedure.

[0107] The raw materials were weighed so as to have the ratios shown in Table 3, and kneaded to prepare hydraulic compositions (kneading step). The blast furnace slag powder used was ground granulated blast furnace slag 4000 as specified in JIS A 6206 (2013).

[0108] In this example, magnesium peroxide is used as the inorganic peroxide, and no alkaline irritant is added.

[0109] Next, the obtained hydraulic composition was filled into a mold to form a molded body (molding step).

[0110] The molded body was demolded from the mold (demolding step). The demolding step was immediate demolding, which was carried out immediately after the molding step.

[0111] After the demolding step, the compact was steam cured in an environment of 65° C. After the steam curing, natural curing was also carried out for an additional 7 days (curing step).

[0112] The obtained hardened body was evaluated as described above. The evaluation results are shown in Table 4. [Example 2-2] Raw materials were weighed out so as to obtain the ratios shown in Table 3 and kneaded to prepare a hydraulic composition (kneading step). In Example 2-2, magnesium peroxide, which is an inorganic peroxide, was used in the unit amount shown in Table 3, and soda ash was added as an alkaline stimulant.

[0113] Apart from the above, a molded body and a hardened body were produced under the same conditions as in Example 2-1, and evaluated. The evaluation results are shown in Table 4. [Example 2-3] A hydraulic composition was prepared by kneading raw materials weighed out to obtain the ratios shown in Table 3 (kneading step). In Example 2-3, calcium peroxide, an inorganic peroxide, was used in the unit amount shown in Table 3. In this case, calcium peroxide was mixed with a bulking agent to adjust the calcium peroxide concentration to 32 mass% to improve handleability. The inorganic peroxide mixed with the bulking agent was added so that the unit amount was the value shown in Table 3.

[0114] For this reason, in Table 3, the unit amount of calcium peroxide, which is an inorganic peroxide, is 20 kg / m ３ However, the unit amount of calcium peroxide excluding the bulking agent is 6.4 kg / m ３ becomes.

[0115] Calcium hydroxide is added instead of soda ash as an alkaline stimulant.

[0116] Except for the above points, molded articles and cured articles were produced under the same conditions as in Example 2-1, and evaluations were carried out. The evaluation results are shown in Table 4.

[0117]

[0118] According to Table 4, it was confirmed that the compressive strength of all of Examples 2-1, 2-2, and 2-3 at least met the low category of compressive strength category 08 for building concrete blocks in JIS A 5406 (2023). In other words, it was confirmed that the hydraulic composition according to one embodiment of the present disclosure has hardening properties and sufficient compressive strength, regardless of the type of inorganic peroxide or alkaline activator. In particular, in Examples 2-2 and 2-3, in which an alkaline activator was added, the compressive strength was 16 N / mm ２ It was confirmed that the specimens had high compressive strength.

[0119] According to the results shown in Table 4, in Examples 2-1 and 2-2 in which magnesium peroxide was added as a hardening accelerator, and in Example 2-3 in which calcium hydroxide was used as an alkaline irritant, ＊ It was confirmed that the value of was greater than 0. In other words, it was confirmed that the blue coloring could be reduced in the hardened bodies of Examples 2-1 to 2-3, regardless of the type of inorganic peroxide or alkaline activator. [Experimental Example 3] In Experimental Example 3, the influence of the Blaine specific surface area of ​​blast furnace slag powder was investigated. [Example 3-1] A hydraulic composition and a hardened body were manufactured according to the following procedure.

[0120] The raw materials were weighed to obtain the ratios shown in Table 5 and kneaded to prepare hydraulic compositions (kneading step). The blast furnace slag powder used was ground blast furnace slag 6000 as specified in JIS A 6206 (2013), and the specific evaluation value of the Blaine specific surface area was 5840 cm. ２ / g.

[0121] In Example 3-1, calcium peroxide, an inorganic peroxide, was used in the unit amount shown in Table 5. In this case, the calcium peroxide was mixed with a bulking agent to make the calcium peroxide concentration 32 mass % to improve handleability. The inorganic peroxide mixed with the bulking agent was added so that the unit amount was the value shown in Table 5.

[0122] Therefore, in Table 5, the unit amount of calcium peroxide, which is an inorganic peroxide, is 110 kg / m ３ However, the unit amount of calcium peroxide excluding the bulking agent is 35.2 kg / m ３ becomes.

[0123] Next, the obtained hydraulic composition was filled into a mold to form a molded body (molding step).

[0124] The molded body was demolded from the mold (demolding step). The demolding step was immediate demolding, which was carried out immediately after the molding step.

[0125] After the demolding step, the compact was steam cured in an environment of 65° C. After the steam curing, natural curing was also carried out for an additional 7 days (curing step).

[0126] The hardened body thus obtained was subjected to the evaluations described above. The evaluation results are shown in Table 6. [Example 3-2] As the blast furnace slag powder, blast furnace slag ground powder 8000 specified in JIS A 6206 (2013) was used, and the specific evaluation value of the Blaine specific surface area was 8150 cm ２ / g.

[0127] Except for the above points, molded articles and cured articles were produced under the same conditions as in Example 3-1, and evaluations were carried out. The evaluation results are shown in Table 6.

[0128]

[0129] According to the results shown in Table 6, the compressive strength was 16 N / mm in both Example 3-1 and Example 3-2. ２ It was confirmed that the blast furnace slag powder had high compressive strength regardless of its Blaine value.

[0130] According to the results shown in Table 6, regardless of the Blaine specific surface area of ​​the blast furnace slag powder, b ＊ It was confirmed that the value of was greater than 0. That is, it was confirmed that the blue color was reduced in both the hardened bodies of Example 3-1 and Example 3-2. [Experimental Example 4] In Experimental Example 4, the production of a hardened body by pour molding was investigated. [Example 4-1] A hydraulic composition and a hardened body were produced according to the following procedure.

[0131] The raw materials were weighed so as to have the ratios shown in Table 7 and kneaded to prepare hydraulic compositions (kneading step). The blast furnace slag powder used was ground granulated blast furnace slag 4000 as specified in JIS A 6206 (2013).

[0132] In Example 4-1, calcium peroxide, an inorganic peroxide, was used in the unit amount shown in Table 7. In this case, the calcium peroxide was mixed with a bulking agent to make the calcium peroxide concentration 32 mass % to improve handleability. The inorganic peroxide mixed with the bulking agent was added so that the unit amount was the value shown in Table 7.

[0133] For this reason, in Table 7, the unit amount of calcium peroxide, which is an inorganic peroxide, is 34 kg / m ３ However, the unit amount of calcium peroxide excluding the bulking agent is 10.88 kg / m ３ becomes.

[0134] To prevent the unit water content from becoming excessively large, a water-reducing agent, which is a chemical admixture for concrete, is used, as shown in Table 7.

[0135] Next, the obtained hydraulic composition was poured into a mold to form a molded body (molding step).

[0136] The molded body was demolded from the mold (demolding step). Note that the demolding step was carried out after it was confirmed that the molded body had sufficiently hardened after the molding step.

[0137] After the demolding process, underwater curing was carried out (curing process).

[0138] The cured product was evaluated as described above. The evaluation results are shown in Table 8.

[0139] Four types of test specimens (hardened specimens) were prepared with different curing periods (material ages): 3 days (3d), 7 days (7d), 14 days (14d), and 28 days (28d), and compressive strength tests were conducted. Color evaluation using a colorimeter was performed on the test specimens cured for 3 days. [Example 4-2] The unit amount of calcium peroxide, an inorganic peroxide, was changed, and soda ash, an alkaline irritant, was not added. Furthermore, components other than calcium peroxide and soda ash were weighed and mixed to achieve the unit amounts shown in Table 7.

[0140] Except for the above points, molded articles and cured articles were produced under the same conditions as in Example 4-1, and evaluations were carried out. The evaluation results are shown in Table 8.

[0141]

[0142] According to the results shown in Table 8, in both Example 4-1 and Example 4-2, the compressive strength was 16 N / mm ２ It was confirmed that the specimens had high compressive strength, exceeding the age of 100 days. In particular, the specimens with longer ages had higher compressive strength, demonstrating that the specimens had higher compressive strength than the other experimental examples.

[0143] According to the results shown in Table 8, in Examples 4-1 and 4-2, the test specimens were cured for three days, which is the period when the blue color is most likely to appear. ＊ The value of was greater than 0, and it was confirmed that the blue color was reduced. [Notes] (1) A hydraulic composition comprising a hydraulic material and a hardening accelerator, wherein the hydraulic material comprises blast furnace slag powder, and the hardening accelerator comprises an inorganic peroxide. (2) The hydraulic composition according to (1), wherein the hardening accelerator further comprises an alkaline activator. (3) The hydraulic composition according to (1) or (2), wherein the inorganic peroxide comprises one or more selected from calcium peroxide and magnesium peroxide. (4) The hydraulic composition according to (1) or (2), wherein the hardening accelerator is contained in a ratio of 3 to 25 parts by mass per 100 parts by mass of the hydraulic material. (5) The hydraulic composition according to (1) or (2), wherein the hardening accelerator is contained in an amount of 3 to 25 parts by mass per 100 parts by mass of the hydraulic material. (6) The hydraulic composition further comprising water, wherein the unit water amount is 130 L / m. ３(6) A hardened product of the hydraulic composition according to (1) or (2). (7) A method for producing a hardened product, comprising: a kneading step of kneading a hydraulic material, a hardening accelerator, and water to form a hydraulic composition; a molding step of filling the hydraulic composition into a mold to form a shaped body; and a demolding step of demolding the shaped body from the mold, wherein the hydraulic material contains blast furnace slag powder, and the hardening accelerator contains an inorganic peroxide. (8) A method for producing a hardened product, comprising: a kneading step of kneading a hydraulic material, a hardening accelerator, and water to form a hydraulic composition; a molding step of filling a mold with the hydraulic composition to form a shaped body; and a demolding step of demolding the shaped body from the mold. ３ (9) The method for producing a hardened body according to (7) or (8), further comprising a curing step of steam curing the molded body in an environment of 40°C or higher after the demolding step.

[0144] This application claims priority based on Japanese Patent Application No. 2024-062854 filed with the Japan Patent Office on April 9, 2024, and Japanese Patent Application No. 2024-111471 filed with the Japan Patent Office on July 11, 2024. The entire contents of Japanese Patent Application No. 2024-062854 and Japanese Patent Application No. 2024-111471 are incorporated by reference into this international application.

Claims

1. A hydraulic composition comprising a hydraulic material and a hardening accelerator, but not containing cement, wherein the hydraulic material comprises blast furnace slag powder, and the hardening accelerator is composed only of inorganic peroxides, and does not contain any alkaline stimulants other than the inorganic peroxides.

2. The hydraulic composition according to claim 1, wherein the inorganic peroxide comprises at least one selected from calcium peroxide and magnesium peroxide.

3. The hydraulic composition according to claim 1 or 2, which contains the hardening accelerator in a ratio of 3 to 25 parts by mass per 100 parts by mass of the hydraulic material.

4. It further contains water, and the unit water volume is 130 L / m ３ The hydraulic composition according to claim 1 or 2, wherein:

5. A hardened product of the hydraulic composition according to claim 1 or 2.

6. A method for producing a hardened body, comprising: a kneading step of kneading a hydraulic material, a hardening accelerator, and water to form a hydraulic composition; a molding step of filling a mold with the hydraulic composition to form a shaped body; and a demolding step of demolding the shaped body from the mold, wherein the hydraulic material contains blast furnace slag powder, the hardening accelerator is composed only of inorganic peroxides and does not contain any alkaline stimulants other than the inorganic peroxides, and the hydraulic composition does not contain cement.

7. The unit water content of the hydraulic composition obtained in the kneading step is 130 L / m ３ The method for producing a cured body according to claim 6, wherein the cured body is:

8. The method for producing a hardened body according to claim 6 or 7, further comprising a curing step of steam curing the molded body in an environment of 40°C or higher after the demolding step.

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