Hydraulic composition, hardened body, and method for producing hardened body

Abstract

The object of the present invention is to provide a hydraulic composition containing blast furnace slag powder, which can reduce the blue color that appears immediately after curing when made into a hardened product. The present invention relates to a composition comprising a hydraulic material and a hardening accelerator, The hydraulic material includes blast furnace slag powder, The hydraulic composition, wherein the hardening accelerator comprises an inorganic peroxide.

Description

[Technical field]

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

[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, where the binder contains 30% by weight or more of ground granulated blast furnace slag to form a concrete block, applying a decorative finish to the surface of the concrete block, and subjecting the decorative finish surface of the concrete block to an oxidation treatment. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-91207 A Summary of the Invention [Problem to be solved by the invention]

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

[0005] Although the blue color of the hardened body fades over time, it may take several months for the color to fade. In addition, since the hardened body is often stored in a stack, the blue color may not fade even after several months on the surface that is not exposed to the outside air. For this reason, when concrete blocks or the like are manufactured as hardened bodies of hydraulic compositions, it is necessary to wait until the blue color fades sufficiently before shipping, which causes a significant hindrance to the inspection and shipping of concrete blocks. Therefore, in the past, treatments were performed on the hardened body to fade the blue color.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to 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. [Means for solving the problem]

[0007] The hydraulic composition of the present disclosure includes a hydraulic material and a hardening accelerator, Does not contain cement The hydraulic material includes blast furnace slag powder, The curing accelerator is an inorganic peroxide. It is composed only of inorganic peroxides and does not contain any alkaline irritants other than the inorganic peroxides. . Effect of the Invention

[0008] The present invention can provide a hydraulic composition containing blast furnace slag powder, which can reduce the blue color that appears immediately after curing when made into a hardened product. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0010] In this specification, the hydraulic composition means a composition that hardens by a chemical reaction when mixed with water. The hydraulic composition may be a mixture of solid powders that does not contain water, and may 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 expressed as hydraulic powder. When the hydraulic composition contains water, the hydraulic composition may be expressed as water-containing hydraulic composition, and when the hydraulic composition has a particularly high water content and high fluidity, the hydraulic composition may be expressed as hydraulic slurry. (1) Ingredients contained in hydraulic compositions Hereinafter, the components contained in the hydraulic composition of this embodiment will be described. (1-1) Hydraulic material The hydraulic composition of this embodiment can 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 applied.

[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 in 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 an alkaline stimulus. Since blast furnace slag powder is a by-product of steelmaking, the carbon dioxide emissions during its manufacture are counted in the steelmaking process. For this reason, 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 hydraulic composition, it is preferable that the Blaine value is high, for example, 3000 Blaine or more, and more preferably 4000 Blaine or more.

[0016] There is no particular upper limit to the Blaine value of the blast furnace slag powder, but since a higher Blaine value tends to result in poorer handling, such as adhesion to the inside of storage silos, a Blaine value of 8,000 or less is preferable.

[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 granulated blast furnace slag.

[0018] In addition, 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, for 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, blast furnace slag powder with a Blaine specific surface area of ​​4000 to 8000 is defined as a surface area of ​​3500 cm 2 / g or more 10000cm 2 This means that the Cr content 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 only of blast furnace slag powder, 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 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 a hydraulic material, the total content 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, etc.

[0028] The unit amount of hydraulic material-hardening accelerator, 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 and 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 hydraulic material-hardening accelerator amount is 200 kg / m 3 More than 600kg / m 3 By satisfying the following, it is possible to at least satisfy the compressive strength category A (08) for basic form blocks of JIS A 5406 (2023).

[0030] In particular, when high strength is required for the hardened body 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 unit amount means the mass of the target material contained in a unit volume of the kneaded product of the hydraulic composition containing water, which is prepared in the process of producing a hardened body, for example, in the kneading step described below. Therefore, the unit amount of hydraulic material-hardening accelerator means the total mass of the hydraulic material and hardening accelerator contained in a unit volume of the kneaded product of the hydraulic composition containing water. (1-2) Curing accelerator (1-2-1) About hardening accelerators The blast furnace slag powder has latent hydraulic properties, which means that it hardens when exposed to an alkaline stimulus. The hardening accelerator is a material that imparts an alkaline stimulus to the blast furnace slag powder when mixed with water together with the blast furnace slag powder. Therefore, the hardening accelerator is a material that can impart an alkaline stimulus to the blast furnace slag powder when mixed with water. (Inorganic peroxide) The more the content of blast furnace slag powder in the hydraulic composition increases, and the more accelerated curing is performed using steam after molding the hydraulic composition, the more likely the hardened product of the hydraulic composition will have a strong blue color immediately after curing. This is thought to be because the sulfur component contained in the blast furnace slag powder forms a sulfur salt, which develops color and thus produces the blue color.

[0032] Although the blue color of the hardened body fades over time, it may take several months for the color to fade. In addition, since the hardened body is often stored in a pile, the blue color may not fade even after several months on the surface that is not exposed to the outside air. For this reason, when concrete blocks or the like are manufactured as the hardened body of the hydraulic composition, it is necessary to wait until the blue color fades sufficiently before shipping, which causes a significant hindrance to the inspection and shipping of the concrete blocks.

[0033] Therefore, the inventors of the present invention conducted a study and found that when the curing accelerator contains an inorganic peroxide, the blue color of the cured product can be reduced. The curing accelerator may be composed of only 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, the calcium peroxide reacts with water according to the chemical formula (1) below to produce calcium hydroxide and hydrogen peroxide.

[0037] CaO2+2H2O→Ca(OH)2+H2O2··(1) Furthermore, since hydrogen peroxide functions as an oxidizing agent, it is believed that when the hydraulic composition contains an 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 peroxide reacts with water, it generates hydroxide salt in addition to hydrogen peroxide. The hydroxide salt dissolves in water and exhibits alkalinity, so it provides an alkaline stimulus to the blast furnace slag powder and also functions 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 the present embodiment may also contain multiple types of inorganic peroxides containing different elements.

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

[0041] In this specification, the alkaline earth metal element refers to an alkaline earth metal element in a broad sense, that is, examples of the alkaline earth metal element include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

[0042] As the inorganic peroxide, it is preferable to use one or more selected from lithium peroxide (Li2O2), sodium peroxide (Na2O2), potassium peroxide (K2O2), magnesium peroxide (MgO2), calcium peroxide (CaO2), and barium peroxide (BaO2). In particular, because of low cost and excellent handling properties, it is preferable that the inorganic peroxide contains one or more selected from calcium peroxide and magnesium peroxide, and the inorganic peroxide may be composed of only one or more selected from calcium peroxide and magnesium peroxide.

[0043] In particular, since it is low cost and easily available, the inorganic peroxide preferably contains calcium peroxide, and the inorganic peroxide may be composed only of calcium peroxide.

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

[0045] In order to improve the handling properties, the inorganic peroxide may be mixed with other bulking agents to form a mixture. When the inorganic peroxide is 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 making the concentration of the inorganic peroxide contained in the mixture 10% by mass or more, the concentration of the inorganic peroxide in the mixture can be sufficiently high, and the amount of the mixture added when preparing the hydraulic composition can be reduced. In addition, by making the concentration of the inorganic peroxide contained in the mixture 35% by mass or less, the reactivity of the inorganic peroxide in the mixture can be adjusted and stabilized, thereby improving the handling properties. In addition, when the mixture contains multiple types of inorganic peroxide, it is preferable that the total concentration of the inorganic peroxides satisfies the above range. In addition, the mixture may be used as a powder as described above, or may be used as a molded body such as granules. (Alkaline stimulant) The hardening accelerator may further include an alkaline activator.

[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] As the alkaline irritant, for example, one or more selected from hydroxides and carbonates can be preferably used. In addition, the alkaline irritant preferably contains one or more elements selected from alkali metal elements and alkaline earth metal elements.

[0048] Therefore, the alkali stimulant 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. The alkali metal elements and alkaline earth metal elements have already been explained, so their explanation will be omitted. The hydraulic composition of this embodiment may also contain multiple types of alkali stimulants that contain different elements and salts.

[0049] As the alkaline stimulant, for example, one or more selected from calcium hydroxide (Ca(OH)2), sodium hydroxide (NaOH), potassium hydroxide (KOH), potassium carbonate (K2CO3), and sodium carbonate (Na2CO3) can be more preferably used.

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

[0051] The hardening 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 hardening accelerator is a mixture of inorganic peroxide and an alkaline stimulant.

[0052] However, when the ratio of the alkali stimulant contained in the hardening accelerator is high, the blue color of the hardened 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 (CaCO3), which precipitates when calcium oxide (CaO), the main component of cement, reacts with water and carbon dioxide gas.

[0054] In the course of the inventors' research into hydraulic compositions, they found that when they prepared hydraulic compositions 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 body. That is, although the efflorescence in general 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 revealed 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 a molded body or a cured body. In addition, by increasing the proportion of inorganic peroxide in the curing accelerator, the occurrence of efflorescence can be particularly reduced. Therefore, the mixing ratio of the inorganic peroxide and the alkaline irritant in the curing accelerator can be selected according to the degree of reduction in the occurrence of efflorescence required for the cured body, the degree of blue color, etc. For example, the proportion of the inorganic peroxide in the total of the inorganic peroxide and the alkaline irritant in the curing accelerator 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 been used as alkaline activators in hydraulic compositions using blast furnace slag powder. Although cement may function as a hydraulic material, the hydraulic composition of this embodiment preferably does not contain various cements regardless of its function.

[0058] In the manufacturing process of cement, limestone (CaCO3) is burned at high temperatures and decarbonated to produce calcium oxide (CaO), which is the main component. 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 a material with less 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 pulverized 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 added intentionally, and does not exclude the possibility of them being mixed in as unavoidable impurities during the manufacturing process, etc. In the hydraulic composition of this embodiment, the content of ground clinker can be set to 1 mass % or less, taking into consideration the mixing in of unavoidable 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 according to the strength required for the hydraulic composition. The hydraulic composition of this embodiment preferably contains 3 to 25 parts by mass of the hardening accelerator, more preferably 3 to 20 parts by mass, per 100 parts by mass of the hydraulic material. The hydraulic material may be composed of only blast furnace slag powder, or may contain fly ash or limestone in addition to the blast furnace slag powder.

[0061] The hydraulic composition of this embodiment contains 3 parts by mass or more of the hardening accelerator per 100 parts by mass of the hydraulic material, thereby increasing the strength of the hardened body. In addition, by increasing the ratio of the hardening accelerator to the hydraulic material, the strength of the hardened body also increases, but the degree of increase in the strength of the hardened body also saturates at a ratio of about 25 parts by mass of the hardening accelerator per 100 parts by mass of the hydraulic material. For this reason, the hydraulic composition of this embodiment preferably contains 25 parts by mass or less of the hardening accelerator per 100 parts by mass of the hydraulic material. (1-3) Other additives 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 according to 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, for example, using a mold and used as a concrete block or the like. By making the hydraulic composition a hard mix and having zero slump, it becomes possible to immediately demold the composition after filling it into a mold. In other words, by making the hydraulic composition a zero slump, it becomes possible to maintain the molded shape even when it is immediately demolded, 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 3 By setting the temperature below this, zero slump can be achieved, and the productivity of hardened bodies 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 has a unit water amount of 130 L / m 3 More than 500L / m 3 The following may also be used.

[0067] The unit water content means the amount of water per unit volume of the kneaded product of the hydraulic composition containing water, which is 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 It is also possible to use the following. (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 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 an air entraining agent and a water reducing agent, and colorants such as chromium oxide, iron oxide, red iron oxide, and titanium oxide. [Cured body] The hardened product of the present embodiment can 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 contains blast furnace slag powder, and the hardening accelerator contains an inorganic peroxide. Therefore, the hardened body of the present embodiment can reduce the blue color and suppress the generation of efflorescence even immediately after curing.

[0071] Furthermore, according to the hardened body of this embodiment, the amount of carbon dioxide emitted during production can be reduced, making it possible to provide a hardened body with low environmental impact.

[0072] The hardened body of the present embodiment may be a hardened product of a molded body obtained by molding the hydraulic composition according to one aspect of the present disclosure into a predetermined shape. The hardened body of the present embodiment may be a concrete block, and may be one or more types selected from, for example, architectural concrete blocks such as hollow blocks and formwork blocks, and paving concrete blocks such as interlocking blocks. Although the term "concrete block" is used because of the use of a common trade name, it is preferable that the hydraulic composition according to one aspect of the present disclosure does not contain cement, and therefore, the concrete block, which is the hardened product thereof, does not preferably contain a cement component.

[0073] The hardened body of the present embodiment can reduce the blueness of 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 the present embodiment does not contain an inorganic peroxide and contains only an alkaline irritant, L * a * b * b in color space (JIS Z 8781-4(2013)) *The color can be compared, for example, between a hardened body using a hydraulic composition in which the inorganic peroxide is replaced with the same mass of an alkali irritant. The color may also be compared between a hardened body using a hydraulic composition that does not contain an inorganic peroxide as a hardening accelerator, contains only an alkali irritant, and has the same unit amounts of other components.

[0074] The hardened body of the present embodiment is, for example, L * a * b * b in color space * can also be greater than 0. [Method of manufacturing the hardened body] The method for producing a hardened body of the present embodiment may include the following kneading step, molding step, and demolding step. Note that, since the method for producing a hardened body of the present 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, some of the items already explained will not be described. Each step will be explained below. (1) Mixing process In the kneading step, a hydraulic material, a hardening accelerator, and water are kneaded to form a hydraulic composition. The hydraulic material may include blast furnace slag powder. The hardening accelerator may include an inorganic peroxide.

[0075] In the kneading step, the components that can be contained in the hydraulic composition can be kneaded. Each component has already been explained, so the explanation will be omitted. Since water is also added in the kneading step, a water-containing hydraulic composition that is a hydraulic composition containing water can be 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 setting the value below this, zero slump can be achieved and immediate demolding can be performed during the molding process, thereby increasing the productivity of concrete blocks, etc.

[0077] In addition, when pouring, the unit water volume is 130L / m 3More than 500L / m 3 The following may also be used. (2) Molding process In the molding step, the hydraulic composition can be 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 or the like to be manufactured. (3) Demolding process 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 product can be demolded at a timing depending on the fluidity of the hydraulic composition constituting the molded product, etc., so that the demolded molded product can maintain the desired shape.

[0080] For example, when 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. That is, immediate demolding can be carried out. By making it possible to carry out immediate demolding, the productivity of the hardened body can be increased. (4) Other processes The method for producing a cured body according to the present embodiment may further include an optional step. (4-1)Curing process The method for producing a hardened body according to the present embodiment may also include 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 steam curing equipment in an environment of 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 time for which steam curing is performed is not particularly limited, but for example, the time for heating to the above temperature range may be 2 hours or more and 12 hours or less.

[0083] In the curing step, curing can 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 about 3 hours to 5 hours. When curing 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 increase the initial strength of the hardened body even if the hydraulic material contains a large amount of blast furnace slag powder. Curing in an autoclave can also reduce the occurrence of efflorescence. EXAMPLES

[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 evaluation was performed using 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 step, 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 so as to obtain the ratio shown in Table 1, and mixed to prepare a hydraulic composition (mixing step). The blast furnace slag powder used was ground granulated 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 "4000 Blaine blast furnace slag powder" 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 process). The demolding process was immediate demolding, which was carried out immediately after the molding process.

[0090] After the demolding process, the molded body was steam cured in an environment of 65°C. After the steam curing, it was further allowed to naturally cure for 7 days (curing process). In other words, the following evaluations were made on the hardened body 7 days after the steam curing.

[0091] The obtained cured bodies were evaluated as described above. The evaluation results are shown in Table 2. [Comparative Example 1-1] A hydraulic composition was prepared by kneading the raw materials weighed out so as to obtain the ratio shown in Table 1 (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] Except for the above, molded and cured products were produced and evaluated under the same conditions as in Example 1-1. The evaluation results are shown in Table 2. [Example 1-2] A hydraulic composition was prepared by kneading the raw materials weighed so as to obtain the ratio shown in Table 1 (kneading step). In Example 1-2, a black pigment was further added so that the occurrence of efflorescence could be confirmed.

[0093] Except for the above, molded and cured products were produced and evaluated under the same conditions as in Example 1-1. The evaluation results are shown in Table 2. [Comparative Example 1-2] The raw materials were weighed so as to obtain the ratio shown in Table 1, and mixed to prepare a hydraulic composition (mixing 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, molded and cured products 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] The raw materials were weighed so as to have the ratio shown in Table 1 and kneaded to prepare a hydraulic composition (kneading step).

[0095] In Example 1-3, no alkaline stimulant was used as the hardening accelerator, and only calcium peroxide, which is 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 a hardening accelerator, and only calcium peroxide, which is an inorganic peroxide, was added. In this case, the inorganic peroxide was added in a larger amount than in Example 1-3 so that the unit amount of the inorganic peroxide was the value shown in Table 1.

[0097] In Examples 1-5, no alkaline irritant was used as a hardening accelerator, and only calcium peroxide, which is an inorganic peroxide, was added. In this case, calcium peroxide was mixed with a bulking agent to make the calcium peroxide concentration 35% by mass, which improved handling properties. By making calcium peroxide 35% by mass or less, it is no longer subject to the application 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] For this reason, the unit amount of inorganic peroxide (calcium peroxide) in Table 1 is 110 kg / m 3 However, the unit amount of calcium peroxide excluding the bulking agent is 38.5 kg / m 3 become.

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

[0100] [Table 1]

[0101] [Table 2] 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 specimen had high compressive strength.

[0102] For Examples 1-3, the compressive strength was 16 N / mm 2 In Examples 1-4 and 1-5, where the amount of inorganic peroxide added was increased, the compressive strength was 16 N / mm 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 strength was higher than that of the corresponding Comparative Examples 1-1 and 1-2. * It was confirmed that the value of b has increased and the blue hue has been 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 has increased and the blue hue has been 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 results were also higher than those in Comparative Example 1-1. * It was confirmed that the value of b has increased and the blue hue has been reduced. * It was confirmed that the value was greater than 0.

[0106] In addition, when comparing Example 1-2, in which a black pigment was added, with Comparative Example 1-2, the L *It was confirmed that the occurrence of efflorescence was reduced in Example 1-2. Note that, since Example 1-1, Example 1-3, Example 1-4, Example 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 obtain the ratio shown in Table 3, and mixed to prepare a hydraulic composition (mixing step). The blast furnace slag powder used was ground granulated blast furnace slag 4000 as specified in JIS A 6206 (2013).

[0108] In this embodiment, 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 process). The demolding process was immediate demolding, which was carried out immediately after the molding process.

[0111] After the demolding process, the green body was steam cured in an environment of 65° C. After the steam curing, natural curing was also performed for an additional 7 days (curing process).

[0112] The obtained cured bodies were evaluated as described above. The evaluation results are shown in Table 4. [Example 2-2] The raw materials were weighed so as to obtain the ratio shown in Table 3, and mixed to prepare a hydraulic composition (mixing step). In Example 2-2, the inorganic peroxide, magnesium peroxide, was used in the unit amount shown in Table 3, and soda ash was added as an alkaline irritant.

[0113] Except for the above, molded and cured products were produced under the same conditions as in Example 2-1, and were evaluated. The evaluation results are shown in Table 4. [Example 2-3] The raw materials were weighed out so as to obtain the ratio shown in Table 3, and kneaded to prepare a hydraulic composition (kneading step). In Example 2-3, calcium peroxide, which is an inorganic peroxide, was used in the unit amount shown in Table 3. In this case, the calcium peroxide was mixed with a bulking agent to make the calcium peroxide concentration 32 mass% to improve handling. The inorganic peroxide was added so that the unit amount mixed with the bulking agent became 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 set to 20 kg / m 3 However, the unit amount of calcium peroxide excluding the bulking agent is 6.4 kg / m 3 become.

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

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

[0117] [Table 3]

[0118] [Table 4] According to Table 4, it was confirmed that the compressive strength in all of Examples 2-1, 2-2, and 2-3 at least met the low category of compressive strength category 08 for architectural 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 irritant. In particular, in Examples 2-2 and 2-3, in which an alkaline irritant was added, the compressive strength was 16 N / mm 2 It was confirmed that the specimen 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 was greater than 0. In other words, it was confirmed that the blue color tone could be reduced in the cured bodies of all of Examples 2-1 to 2-3, regardless of the type of inorganic peroxide or alkaline irritant. [Experimental Example 3] In Experimental Example 3, the effect of the Blaine specific surface area of ​​blast furnace slag powder was examined. [Example 3-1] A hydraulic composition and a hardened body were produced according to the following procedure.

[0120] The raw materials were weighed so as to obtain the ratio shown in Table 5, and mixed to prepare a hydraulic composition (mixing step). The blast furnace slag powder used was 6000 ground granulated blast furnace slag 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, which is an inorganic peroxide, is used in the unit amount shown in Table 5. In this case, the calcium peroxide is mixed with a bulking agent to make the calcium peroxide concentration 32 mass% to improve handling. The inorganic peroxide is added so that the unit amount mixed with the bulking agent becomes the value shown in Table 5.

[0122] For this reason, 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 become.

[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 process). The demolding process was immediate demolding, which was carried out immediately after the molding process.

[0125] After the demolding process, the green body was steam cured in an environment of 65° C. After the steam curing, natural curing was also performed for an additional 7 days (curing process).

[0126] The obtained cured bodies were evaluated as described above. The evaluation results are shown in Table 6. [Example 3-2] The blast furnace slag powder used was 8000 granulated blast furnace slag as specified in JIS A 6206 (2013), and the specific evaluation value of the Blaine specific surface area was 8150 cm 2 / g.

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

[0128] [Table 5]

[0129] [Table 6] According to the results shown in Table 6, the compressive strength was 16 N / mm in both Examples 3-1 and 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 was greater than 0. That is, it was confirmed that the blue color tinge was reduced in both the cured bodies of Example 3-1 and Example 3-2. [Experimental Example 4] In Experimental Example 4, the production of a hardened body by casting 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 obtain the ratio shown in Table 7, and mixed to prepare a hydraulic composition (mixing 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, which is an inorganic peroxide, is used in the unit amount shown in Table 7. In this case, the calcium peroxide is mixed with a bulking agent to make the calcium peroxide concentration 32 mass% to improve handling. The inorganic peroxide is added so that the unit amount mixed with the bulking agent becomes 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 become.

[0134] In order 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 process). The demolding process was carried out after confirming that the molded body was sufficiently cured after the molding process.

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

[0138] The obtained cured bodies were 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 days (material ages), namely, 3 days (3d), 7 days (7d), 14 days (14d), and 28 days (28d), and tests were conducted on the compressive strength. Color evaluation using a colorimeter was performed on the test specimens that had been cured for 3 days. [Example 4-2] The unit amount of calcium peroxide, which is an inorganic peroxide, was changed, and soda ash, which is an alkaline irritant, was not added. In addition, the ingredients other than calcium peroxide and soda ash were weighed and mixed to obtain the unit amounts shown in Table 7.

[0140] Except for the above, molded and cured products were produced under the same conditions as in Example 4-1, and were then evaluated. The evaluation results are shown in Table 8.

[0141] [Table 7]

[0142] [Table 8] According to the results shown in Table 8, the compressive strength was 16 N / mm in both Example 4-1 and Example 4-2, regardless of the age of the material. 2It was confirmed that the specimens had high compressive strength, exceeding the age of 10 days. In particular, the specimens with longer ages had higher compressive strength, and it was confirmed 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, even though the test specimens were cured for 3 days, which is the period when the blue color is most likely to appear, * It was confirmed that the value was greater than 0, and the blue tinge was reduced.

Claims

1. It contains a hydraulic material and a hardening accelerator, but does not contain cement, The hydraulic material includes blast furnace slag powder, The hydraulic composition, wherein the hardening accelerator is composed only of an inorganic peroxide and does not contain any alkaline stimulant other than the inorganic peroxide.

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

3. 3. The hydraulic composition according to claim 1, further comprising the hardening accelerator in an amount of 3 parts by mass or more and 25 parts by mass or less relative to 100 parts by mass of the hydraulic material.

4. It further contains water, and the unit water amount 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 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 molded body; A demolding step of demolding the molded body from the mold, The hydraulic material includes blast furnace slag powder, The curing accelerator is composed only of an inorganic peroxide and does not contain any alkaline irritant other than the inorganic peroxide; The method for producing a hardened body, wherein the hydraulic composition does not contain cement.

7. The unit water amount 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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