Manufacturing method for cured bodies

Abstract

To provide a new method for producing a hardened body capable of reducing carbon dioxide emissions, including a raw material production process, and effectively utilizing natural resources in Japan.SOLUTION: A method for producing a hardened body includes the steps of: heating and mixing volcanic glass material derived from volcanic ejecta with an alkaline solution and further adding inorganic acid to obtain an active suspension; obtaining a mixture of the active suspension, aggregate, and a calcium source; and filling the mixture into a mold, and then forming, demolding, and curing the mixture, wherein the active suspension includes aluminosilicate-activated particles and aluminosilicate sol.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing a novel cured body that can be used for buildings and the like.

Background Art

[0002] In order to suppress global warming, efforts have been made to suppress the emission of greenhouse gases such as carbon dioxide and aim for carbon neutrality. Therefore, in the manufacturing industry as well, it is required to suppress carbon dioxide emissions during the manufacturing process as much as possible.

[0003] Here, in concrete buildings, a large amount of hydraulic cement is used as a material. Portland cement, which is the mainstream of hydraulic cement, is an artificial cement and emits a large amount of carbon dioxide during firing at around 1450°C in its manufacturing process. Therefore, from the perspective of suppressing carbon dioxide, research on cured bodies and curing methods that do not use Portland cement has been underway.

[0004] Among such movements, research and development have been conducted on cured bodies and curing methods based on the pozzolan reaction. The pozzolan reaction is the curing action of ancient cement, which refers to a reaction in which a soluble siliceous material reacts with calcium hydroxide in the presence of water to form an insoluble compound and harden. Cured bodies and curing methods based on the pozzolan reaction do not require firing Portland cement, so it is possible to significantly suppress carbon dioxide emissions.

[0005] Pozzolans are soluble silica-based materials that, while not hydraulic themselves, undergo the pozzolanic reaction described above. Pozzolans include artificial pozzolans such as fly ash discharged from thermal power plants, ferrosilicon, or silica fumes produced during the manufacture of silicon metal in arc-type electric furnaces, and natural pozzolans such as natural volcanic ash. Pozzolans have traditionally been used as admixtures in concrete or cement mixtures. However, the global trend toward reducing carbon dioxide emissions necessitates materials that do not use fly ash discharged from thermal power plants or silica fumes produced in arc-type electric furnaces. Shirasu, known as a natural pozzolanic agent, has low pozzolanic reactivity and therefore does not meet JIS standards in its original form. Conventional hardened materials and hardening methods that utilize pozzolann in practical applications mainly involve using artificial pozzolann as an admixture in concrete or as an admixture in mixed cement.

[0006] Hydraulic lime is a binder that produces less carbon dioxide emissions than cement. There are two types of hydraulic lime: natural hydraulic lime, which is produced by firing clayey limestone that is found in limited areas, and artificial hydraulic lime, which is produced by mixing clay and lime with water and firing it at over 1000°C. Regarding the manufacturing method of high-strength building materials using hydraulic lime, there is a method in which a mixture containing hydraulic lime and water is filled into a mold and cured with carbon dioxide gas (Patent Document 1). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2010-126420 (Claims and other details) [Overview of the project] [Problems that the invention aims to solve]

[0008] The manufacturing method described in Patent Document 1 requires importing natural hydraulic lime, which is sourced mainly from European countries, making it difficult and costly to obtain. Moreover, since natural hydraulic lime is obtained by firing clayey limestone at temperatures above 1000°C, the production of natural hydraulic lime inevitably involves the emission of large amounts of carbon dioxide. Therefore, even if there are no carbon dioxide emissions during the manufacturing process of high-strength building materials using natural hydraulic lime as a raw material, and carbon dioxide is absorbed during curing, considering the manufacturing process of natural hydraulic lime, the emission of large amounts of carbon dioxide was ultimately unavoidable. Furthermore, even when using artificial hydraulic lime, as mentioned above, it is fired at temperatures above 1000°C, so the production of artificial hydraulic lime inevitably involves the emission of large amounts of carbon dioxide.

[0009] The present invention aims to provide a novel method for manufacturing a hardened body that can reduce carbon dioxide emissions, including during the raw material manufacturing process, and effectively utilize domestic natural resources. [Means for solving the problem]

[0010] While conducting research on the effective utilization of shirasu (volcanic ash), the inventors have been studying the use of volcanic glass, the main component of shirasu, as a hardening agent in place of cement due to its excellent reactivity. They found that when volcanic glass is subjected to chemical treatment with acid and alkali solutions, an aqueous solution containing suspended fine particles with a particle size of 0.1 μm or less (aluminosilicate sol) and settled particles activated by the chemical treatment (aluminosilicate activated particles) are obtained, and that both the aluminosilicate sol and the aluminosilicate activated particles can be used as hardening agents.

[0011] This invention is derived from the above findings. In other words, the present invention is a method for producing a hardened body, comprising the steps of: heating and mixing volcanic glass derived from volcanic ejecta with an alkaline solution to obtain an activated suspension by further adding an inorganic acid; obtaining a mixture of the activated suspension, aggregate, and a calcium source; filling the mixture into a mold, molding it, demolding it, and curing it, wherein the activated suspension contains aluminosilicate activated particles and aluminosilicate sol.

[0012] In the step of obtaining a mixture of the active suspension, aggregate, and calcium source according to the present invention, it is preferable that the aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, and that the active suspension is 10 to 110 parts by mass per 100 parts by mass of the total of aggregate and calcium source.

[0013] Furthermore, the present invention is a method for producing a hardened body, comprising the steps of: heating and mixing volcanic glass derived from volcanic ejecta with an alkaline solution to obtain an activated suspension by adding an inorganic acid; obtaining a mixture of aluminosilicate activated particles and aluminosilicate sol, or both, obtained by solid-liquid separation of the activated suspension, aggregate, and a calcium source; and filling the mixture into a mold, molding it, demolding, and curing it.

[0014] In the step of obtaining a mixture of aggregate and calcium source with either aluminosilicate activated particles or aluminosilicate sol, or both, according to the present invention, it is preferable that the aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, and that the aluminosilicate activated particles are 10 to 140 parts by mass or the aluminosilicate sol is 10 to 70 parts by mass or the total of aluminosilicate activated particles and aluminosilicate sol is 10 to 150 parts by mass per 100 parts by mass of the aggregate and calcium source combined.

[0015] Furthermore, the present invention is a method for producing a hardened body, comprising the steps of: heating and mixing volcanic glass derived from volcanic ejecta with an alkaline solution to obtain an activated suspension by adding an inorganic acid; obtaining a mixture of dealkaliated aluminosilicate activated particles obtained by solid-liquid separation of the activated suspension, aggregate, and calcium source by reducing the alkaline component from the aluminosilicate activated particles; and filling the mixture into a mold, molding it, demolding, and curing it.

[0016] In the step of obtaining a mixture of the dealkaliated aluminosilicate activated particles, aggregate, and calcium source according to the present invention, it is preferable that the aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, and that the amount of dealkaliated aluminosilicate activated particles is 10 to 150 parts by mass per 100 parts by mass of the total of aggregate and calcium source.

[0017] In the present invention, it is preferable that the volcanic glass material is volcanic glass granules with a volcanic glass content of 80% by mass or more, which are classified from volcanic ejecta, or volcanic glass fine powder obtained by grinding the volcanic glass granules. It is also preferable that the volcanic glass material is volcanic glass granules obtained by classifying volcanic ash or volcanic rock, or volcanic glass fine powder obtained by grinding or pulverizing the volcanic glass granules.

[0018] In the present invention, it is preferable that the aluminosilicate-activated particles (including dealkalized aluminosilicate-activated particles) are particles with a nucleus consisting of either volcanic glass or zeolite, or both, having a surface covered with aluminosilicate gel, and that the aluminosilicate gel dissolves from the nucleus and forms an active layer on the particle surface.

[0019] In the present invention, the aluminosilicate sol is preferably a colloidal solution in which particles mainly composed of aluminosilicate containing volcanic glass components are dispersed, and the solid content concentration is 10 to 20% by mass.

[0020] In the present invention, it is preferable that the calcium source is a compound that releases calcium ions under wet conditions. In the present invention, in the step of filling the mixture into a mold and molding it, the molding pressure is 30 to 230 MPa, and it is preferable that dehydration occurs during molding.

[0021] In the present invention, in the step of filling the mixture into a mold, molding, demolding, and curing, it is preferable to cure in an atmosphere containing carbon dioxide, and the mass of the cured body is increased by 4% to 33% by mass compared to before curing.Moreover, in the step of filling the mixture into a mold, molding, demolding, and curing, by curing in water, it is also preferable that the specific strength obtained by dividing the compressive strength of the cured body by the density of the cured body is improved by 5% to 250% compared to before curing.Furthermore, in the step of filling the mixture into a mold, molding, demolding, and curing, by curing in a pressurized steam atmosphere, it is also preferable that the specific strength obtained by dividing the compressive strength of the cured body by the density of the cured body is improved by 10% to 250% compared to before curing.

[0022] In the present invention, it is preferable that the specific strength of the cured body is 10 to 75 Nm / g. In the present invention, the aggregate is preferably fine volcanic glass obtained by classifying fine volcanic glass having a volcanic glass content of 80% or more obtained by dry specific gravity separation from shirasu of volcanic ejecta or volcanic ash or volcanic rock generated by rapid cooling of magma. Further, it is also preferable that the aggregate is a fired foam called shirasu balloon or perlite obtained by firing and foaming fine volcanic glass obtained by classifying fine volcanic glass having a volcanic glass content of 80% or more obtained by dry specific gravity separation from shirasu of volcanic ejecta or volcanic ash or volcanic rock generated by rapid cooling of magma.

[0023] Furthermore, in recent years, building technology on the lunar surface in space development has been actively studied. Due to the enormous transportation costs, local production and consumption using lunar rocks (hereinafter referred to as regolith) as building materials are required. Regolith has many similarities with volcanic ejecta, and this technology is applicable.

[0024] In the present invention, the aggregate can also be slaked lime. This slaked lime does not need to be of high purity and may be a compound containing calcium hydroxide. For example, low-purity slaked lime containing impurities such as crystalline minerals can be used. The impurities act as aggregates of the hardened body. Slaked lime can also be obtained as a by-product in the production of carbide method acetylene. It can be obtained by digesting those obtained by firing calcium-containing substances such as natural or animal-derived wastes such as shells and eggshells at 800 to 900 °C in addition to lime. In the present invention, it is preferable that the step of obtaining the mixture includes a primary mixing step of mixing raw materials other than the calcium source and a secondary mixing step of further adding the calcium source to obtain the mixture.

Effects of the Invention

[0025] According to the present invention, it is possible to reduce the emission of carbon dioxide including the production process of raw materials, and a method for producing a hardened body can be provided by effectively utilizing domestic natural resources.

Embodiments for Carrying out the Invention

[0026] The method for producing a hardened body of the present invention will be described more specifically. (Embodiment 1) The method for producing a hardened body according to Embodiment 1 of the present invention includes a step of obtaining an active suspension by heating and mixing volcanic glassy substances derived from volcanic ejecta with an alkaline solution and further adding an inorganic acid, a step of obtaining a mixture of the active suspension, an aggregate, and a calcium source, and a step of filling the mixture into a mold, molding, demolding, and curing. The active suspension contains aluminosilicate activating particles and aluminosilicate sol.

[0027] The volcanic glassy substance is a natural pozzolan containing aluminosilicate and reacts with, for example, calcium hydroxide as a calcium source to have hydraulicity. Therefore, a hardened body can be obtained by mixing the volcanic glassy substance having hydraulicity and an aggregate.

[0028] However, in this embodiment, instead of simply mixing volcanic glass, a calcium source, and aggregate, the process involves pre-heating and mixing volcanic glass derived from volcanic ejecta with an alkaline solution, and then adding an inorganic acid to obtain an activated suspension. Through this process, fine particles with a particle size of 0.1 μm or less are generated from the surface of the volcanic glass particles and suspended in the liquid. At the same time, the surface of the volcanic glass particles is activated. These activated volcanic glass particles are referred to herein as aluminosilicate-activated particles. Furthermore, the suspension obtained by removing the aluminosilicate-activated particles from the activated suspension is referred to herein as aluminosilicate sol. In other words, the activated suspension contains aluminosilicate-activated particles and aluminosilicate sol.

[0029] Both aluminosilicate-activated particles and aluminosilicate sol are rapid-setting pozzolanes that react with a calcium source to become hydraulic. Moreover, they are more active than the volcanic glass material before the above-mentioned process of heating and mixing with an alkaline solution and then adding an inorganic acid, and when hardened, they achieve higher strength (compressive strength) with a shorter curing period. Furthermore, during curing, they absorb carbon dioxide from the air, increasing their strength compared to immediately after molding. As a result, it is possible to obtain a hardened material with more than twice the compressive strength of ordinary concrete. Since air can be used as a carbon dioxide source for strength improvement, the hardened material can be made stronger by absorbing carbon dioxide simply by leaving it in the air.

[0030] The volcanic glass material used as the raw material is obtained by classifying, for example, shirasu (volcanic ash), eliminating the need for calcination or sintering. Therefore, the preparation of the raw material does not involve the emission of large amounts of carbon dioxide. Furthermore, the process of heating and mixing the volcanic glass material with an alkaline solution and then adding an inorganic acid to obtain an activated suspension can be carried out at temperatures below 100°C in an aqueous solution, resulting in low energy consumption and thus low carbon dioxide emissions. Moreover, the hardened body has high strength without necessarily requiring the addition of environmentally harmful Portland cement, making it environmentally friendly in this respect as well. In addition, the hardened body can absorb carbon dioxide, so when the amount of carbon dioxide emitted during the process from raw material to hardened body production is calculated along with the amount of carbon dioxide absorbed by the molded body, the total amount of carbon dioxide emitted is extremely low, making it possible to aim for carbon neutrality.

[0031] Shirasu, used to obtain volcanic glass derived from volcanic ejecta as a raw material, is a mixture of minerals and volcanic glass ejected and deposited by the eruption of the Aira Caldera. Although it is believed to have nearly inexhaustible reserves, its particle size ranges widely from gravel to fine particles, making it difficult to utilize as a resource. In recent years, a technology has been developed to classify shirasu by its composition and particle size into sand, pumice, volcanic glass powder, and clay (Patent No. 6458267). As a result, volcanic glass powder has been standardized as JIS A6209, and its use as a concrete material is now expected.

[0032] The manufacturing method for the cured body of this embodiment provides a new way to utilize shirasu, separate from the volcanic glass fine powder described above. In this method, glassy material derived from volcanic ejecta such as shirasu is heated and mixed with an alkaline solution, and an inorganic acid is added to obtain an activated suspension. This activated suspension is then used as a binder to obtain the cured body. Since both the aluminosilicate activated particles and the aluminosilicate sol in the activated suspension are used as binders, there is no waste, and the volcanic glass material can be effectively utilized.

[0033] Furthermore, in the process of obtaining a mixture of the activated suspension, aggregate, and calcium source, if sand or glass granules obtained by classifying shirasu (volcanic ash) using the technology of the aforementioned Patent No. 6458267, or shirasu balloons or perlite obtained by heating and expanding the glass granules, are used as the aggregate, a hardened body can be obtained using shirasu as the raw material for everything except the calcium source, thereby enabling even more effective utilization of shirasu. Since lime, which is abundant in Japan, can be used as the calcium source, the hardened body can be manufactured using domestic resources. The purity of the calcium source in this invention does not necessarily need to be high, so even low-purity limestone that was not utilized despite being abundant in resources can be used. One example of a calcium source is slaked lime, but any compound containing calcium hydroxide is acceptable, and industrial by-products or waste-derived products are also acceptable.

[0034] To further describe the manufacturing method of the hardened body of this embodiment in detail, step by step, first, in the step of obtaining an active suspension by heating and mixing volcanic glass derived from volcanic ejecta with an alkaline solution and then adding an inorganic acid, the volcanic glass derived from volcanic ejecta can be volcanic glass granules with a volcanic glass content of 80% by mass or more, which have been classified from the volcanic ejecta, or volcanic glass fine powder obtained by crushing the volcanic glass granules. Volcanic ejecta is, for example, shirasu. By classifying the volcanic glass content to 80% by mass or more, the amount of minerals other than volcanic glass, such as quartz and feldspar, can be reduced, and the strength of the hardened body can be increased. Volcanic glass granules refer to particles with a particle size in the range of 0.05 mm to 0.6 mm, and volcanic glass fine powder refers to particles with a particle size in the range of 0.001 mm to 0.05 mm.

[0035] For classifying volcanic ejecta, for example, the technology described in Japanese Patent No. 6458267 can be used. This technology removes pebbles larger than 5 mm in size from volcanic ejecta deposits and supplies the remaining material to an air-table type gravity differential separator that vibrates a perforated plate tilted horizontally at a predetermined angle while blowing air onto the perforated plate from below. The density of the material, 2.5 g / cm³, is then measured and discharged from the upper outlet of the perforated plate in the gravity separator. 3The above-mentioned specific gravity components, plus the density of 2.5 g / cm³ discharged from the lower outlet of the perforated plate of the specific gravity separator. 3 By separating the material into a low specific gravity component (less than 0.05 mm), a dust component that floats up from the perforated plate of the specific gravity separator by airflow and is discharged on the air current, and a component that falls through the holes of the perforated plate of the specific gravity separator and is discharged, the fine aggregate can be recovered from the separated high specific gravity component, or from the high specific gravity component and the component that falls through the perforated plate, thereby obtaining the remaining volcanic glass material, which is separated into volcanic glass material with a particle size of 0.05 mm or more and 0.3 mm or less. Furthermore, by the technology of the above-mentioned Patent No. 6458267, it is possible to obtain volcanic glass material obtained by separating the aggregate and crushing at least one of the separated volcanic glass material with a particle size of 0.05 mm to 0.3 mm, volcanic glass material with a particle size of less than 0.05 mm, and pumice consisting of volcanic glass with a particle size of 0.3 mm or more. A vibrating mill can be an example of a crushing means. In addition to vibrating mills, various mills such as roller mills and jet mills can also be used.

[0036] Furthermore, volcanic glass derived from volcanic ejecta can be volcanic glass granules obtained by classifying volcanic ash or volcanic rocks formed by the rapid cooling of magma, or volcanic glass fine powder obtained by grinding or pulverizing such volcanic glass granules. Volcanic glass granules refer to particles with a particle size in the range of 0.05 mm to 0.6 mm, similar to the volcanic glass granules classified from volcanic ejecta described above, and volcanic glass fine powder refers to particles with a particle size in the range of 0.001 mm to 0.05 mm, similar to the volcanic glass fine powder classified from volcanic ejecta described above. In recent years, large amounts of volcanic ash and pumice (volcanic rock) generated by underwater volcanic eruptions have washed ashore, negatively impacting fishing, passenger ship operations, and the aesthetics of the coast. However, instead of treating this volcanic ash and pumice (volcanic rock) as a nuisance, it can be effectively utilized by using it as a raw material for the volcanic glass material described in this embodiment.

[0037] For classifying volcanic ash or volcanic rock, for example, the technology described in the aforementioned Japanese Patent No. 6458267 can be used. A vibratory mill can be used as a grinding means. In addition to vibratory mills, various other mills such as roller mills and jet mills can also be used. A thoron mill can be used as a grinding means.

[0038] The alkaline solution mixed with the volcanic glass derived from volcanic ejecta is, for example, an aqueous solution of caustic soda. The concentration of caustic soda is preferably in the range of 0.5 to 3 mol / L. If it exceeds 3 mol / L, a uniform active suspension cannot be obtained. If it is less than 0.5 mol / L, the reactivity of the active suspension will be low. A more preferable concentration range for caustic soda is 0.8 to 2 mol / L. In addition to aqueous solutions of caustic soda, aqueous solutions of potassium hydroxide and other solutions can also be used. The heating temperature for the alkaline solution is preferably in the range of 80 to 150°C. The reaction proceeds at temperatures above 80°C. Heating above 150°C is impractical due to the need for a large reaction apparatus. A more preferable temperature is 90 to 100°C.

[0039] Volcanic glass derived from volcanic ejecta is stirred in a heated alkaline solution. At the laboratory level, it has been confirmed that a suspension of sufficient concentration can be obtained in about 5 hours. Next, an inorganic acid is gradually added. The inorganic acid is, for example, sulfuric acid. Dilute sulfuric acid can be used. It is preferable to add an amount of sulfuric acid such that the pH of the solution after addition is 1 to 11. By setting the pH to 1 to 11, an active suspension is obtained in which aluminosilicate activating particles and aluminosilicate sol are generated in the solution in which sodium sulfate is dissolved. The inorganic acid can be sulfuric acid, hydrochloric acid, etc.

[0040] The aluminosilicate-activated particles in the activated suspension (including the dealkalized aluminosilicate-activated particles in Embodiment 3 described later) are particles with a surface covered with aluminosilicate gel, and each of volcanic glass and / or zeolite as the core. The zeolite is produced by the alkali precipitation reaction of the raw material volcanic glass. The aluminosilicate gel covering the surface of the aluminosilicate-activated particles becomes the active layer of the pozzolanic reaction. The degree of formation of the active layer can be determined by the increase in volume of the accumulated activated particles that settle after chemical treatment.

[0041] The aluminosilicate sol in the active suspension is a colloidal solution in which particles mainly composed of aluminosilicate containing volcanic glass components are dispersed, and the solid content concentration is preferably 10 to 20% by mass. If the solid content concentration is 10% by mass or less, the amount of the target component will be insufficient, and the desired strength will not be obtained. If it is 20% by mass or more, heterogeneity of the colloidal particle dispersion is likely to occur, leading to a decrease in the performance of the cured product. The particle size is fine particles of 0.1 μm or less, has a large specific surface area, and is active.

[0042] Next, the process of obtaining a mixture of the active suspension, aggregate, and calcium source will be described in detail. This process involves mixing the active suspension, which is a pozzolanic substance, with the calcium source to obtain a hydraulically hardened material through a reaction between the two.

[0043] Calcium sources are compounds that release calcium ions under wet conditions. Specifically, these include slaked lime, which contains calcium hydroxide, industrial by-products and industrial waste that release calcium ions under wet conditions, as well as cement and hydraulic lime.

[0044] The aggregate can be the same as the general aggregate used in concrete. By using aggregate separated from shirasu (volcanic ash) using the technology of Patent No. 6458267, the shirasu can be effectively utilized. Furthermore, the shirasu can also be effectively utilized by using volcanic glass fine grains with a volcanic glass content of 80% or more, obtained by dry gravity separation from shirasu (volcanic ejecta) using the technology of Patent No. 6458267, or by using volcanic glass fine grains obtained by classifying volcanic ash or volcanic rock produced by the rapid cooling of magma, as the aggregate. In addition, the shirasu can also be effectively utilized by using a calcined foam called shirasu balloon or perlite, which is produced by calcining and foaming volcanic glass fine grains with a volcanic glass content of 80% or more, obtained by dry gravity separation from shirasu (volcanic ejecta) using the technology of Patent No. 6458267, or by classifying volcanic ash or volcanic rock produced by the rapid cooling of magma, as the aggregate. Furthermore, the aggregate It is also possible to use regolith, which has a composition similar to that of volcanic ejecta.

[0045] The aggregate can also be slaked lime. A hardened product can also be manufactured that does not contain conventional aggregates and whose raw materials consist almost entirely of volcanic glass derived from volcanic ejecta and slaked lime.

[0046] When the calcium source is calcium hydroxide, the aggregate / calcium source ratio is preferably 0.2 to 6.0, and the active suspension is preferably 10 to 110 parts by mass per 100 parts by mass of aggregate and calcium source combined. If the aggregate / calcium source ratio is 0.2 or less, the desired strength cannot be obtained due to insufficient aggregate. If it is 6.0 or more, the desired strength cannot be obtained due to insufficient calcium hydroxide. A more preferable aggregate / calcium source ratio is 1.0 to 3.0. Furthermore, if the active suspension is 10 parts by mass or less per 100 parts by mass of aggregate and calcium source combined, the desired strength cannot be obtained due to insufficient binder. If it is 110 parts by mass or more, the moisture content becomes high, making demolding difficult. A more preferable amount of active suspension per 100 parts by mass of aggregate and calcium source combined is 20 to 80 parts by mass.

[0047] When mixing the activated suspension, aggregate, and calcium source, it is preferable to first go through a primary step of mixing the raw materials other than the calcium source. That is, it is preferable to mix the activated suspension and aggregate first. This allows the activated suspension to blend with the aggregate. After the primary step, a secondary step is taken to add the calcium source and obtain the mixture. Since the reaction between the activated suspension and the calcium source proceeds rapidly, it is preferable to go through two steps: a primary step and a secondary step.

[0048] Next, the process of filling the mold with the mixture, molding it, demolding it, and curing it will be described in detail. This process is for hardening the mixture into the desired shape. Similar to ordinary concrete, the process of filling the mold with the mixture, molding it, demolding it, and curing it follows the general procedures for shaping building materials into the desired form.

[0049] In the process of filling a mold with the mixture and molding it, the molding pressure should be at or above a pressure at which dewatering occurs during pressurization and demolding is possible, preferably 30 to 230 MPa. A molding pressure of 30 MPa or higher allows for efficient dewatering, further reduction of alkali, and easier demolding. On the other hand, a pressure of 230 MPa or lower eliminates the need for large-scale manufacturing equipment, which is advantageous in terms of practicality in terms of capital investment and running costs. A more preferable molding pressure is 30 to 165 MPa. By applying such a molding pressure, excess alkali and excess salt are removed by dewatering during molding. This makes it possible to obtain a hardened body with high durability and high specific strength.

[0050] Curing after demolding can be carried out at room temperature in the open air. During molding and curing, the active layer on the surface of the aluminosilicate-activated particles in the active suspension reacts with the calcium source in a pozzolanic reaction to form particles covered with calcium aluminosilicate. Simultaneously, the aluminosilicate sol in the active suspension reacts with the calcium source to produce calcium silicate hydrate. The generated calcium aluminosilicate hydrate fills the gaps between the aggregates, strengthening the bonds and resulting in a high-strength hardened body. Furthermore, the absorption of carbon dioxide from the air further improves the strength. To obtain a high-strength hardened body, it is preferable to cure the material so that its mass increases by 4% to 33% by mass compared to before curing due to carbon dioxide absorption.

[0051] Curing after demolding can be carried out in a carbon dioxide-containing atmosphere with a higher carbon dioxide concentration than air. Curing in a carbon dioxide-containing atmosphere allows the cured body to absorb carbon dioxide, increasing its mass by 4% to 33% compared to before curing. Curing in a carbon dioxide-containing atmosphere with a higher carbon dioxide concentration than air shortens the time required to obtain a high-strength cured body compared to curing in air, thus reducing the curing time. The carbon dioxide concentration higher than air is preferably 5 to 100 vol%. High strength can be achieved in a short time at a concentration of 5 vol% or higher. More preferably, it is 10 vol% or higher. There is no particular upper limit to the carbon dioxide concentration, and for example, it can be carried out in a 100 vol% carbon dioxide atmosphere. Curing in such a way that the mass of the cured body increases by 4% to 33% compared to before curing due to carbon dioxide absorption is preferable to obtain a high-strength cured body.

[0052] Curing after demolding can also be carried out in water. Curing in water can improve the specific strength (compressive strength divided by density) of the hardened material by 5% to 250% compared to before curing. Since a high-strength hardened material can be obtained by curing in water in the same way as concrete, it can be used in buildings and civil engineering structures, and is stronger than ordinary concrete. When a mixture of volcanic glass derived from volcanic ejecta, aggregate, and calcium source was cured in water without performing the step of heating and mixing volcanic glass derived from volcanic ejecta with an alkaline solution and then adding an inorganic acid to obtain an activated suspension according to the present invention, no improvement in strength was observed. In this respect as well, the method of manufacturing the hardened material of the present invention is advantageous. Curing in water can be carried out at a standard temperature of 20°C ± 5°C used for curing concrete. When curing in water, it is preferable to cure the material so that the specific strength (compressive strength divided by density) of the hardened material improves by 5% to 250% compared to before curing in order to obtain a high-strength hardened material.

[0053] Curing after demolding can also be performed in a pressurized steam atmosphere. Curing in a pressurized steam atmosphere can improve the specific strength (compressive strength divided by density) of the cured material by 10% to 250% compared to before curing. A pressurized steam atmosphere can be maintained in the range of pressure 1.5 to 4 atmospheres, humidity 95 to 100%, and temperature 80 to 140°C, and is typically performed under conditions of 2 atmospheres, 98% humidity, and 100°C. When curing in a pressurized steam atmosphere, it is preferable to cure the material in such a way that the specific strength (compressive strength divided by density) improves by 10% to 250% compared to before curing in order to obtain a high-strength cured material.

[0054] After curing, the hardened material has a specific strength of approximately 10 to 75 Nm / g, depending on the material and curing conditions. This specific strength is superior to that of ordinary concrete and is considered suitable for use in buildings and other structures.

[0055] (Embodiment 2) The method for producing a hardened body according to Embodiment 2 of the present invention comprises the steps of: heating and mixing volcanic glass derived from volcanic ejecta with an alkaline solution to obtain an activated suspension by adding an inorganic acid; obtaining a mixture of aluminosilicate activated particles and aluminosilicate sol, or both, obtained by solid-liquid separation of the activated suspension, aggregate, and a calcium source; and filling the mixture into a mold, molding it, demolding, and curing it.

[0056] The manufacturing method for the cured body of Embodiment 2 differs from that of Embodiment 1 in that Embodiment 1 includes a step of obtaining a mixture of an active suspension, aggregate, and a calcium source, whereas Embodiment 2 includes a step of obtaining a mixture of either or both of the aluminosilicate-activated particles and / or aluminosilicate sol obtained by solid-liquid separation of the active suspension, along with aggregate and a calcium source. All other steps are the same. Therefore, in the description of the manufacturing method for the cured body of Embodiment 2 described below, matters that overlap with those described in the manufacturing method for the cured body of Embodiment 1 will be referred to in the description of the manufacturing method for the cured body of Embodiment 1, and redundant descriptions will be omitted.

[0057] In the manufacturing method of the hardened body of Embodiment 1, a mixture of aggregate and calcium source was obtained by using the active suspension as is. However, in the manufacturing method of the hardened body of Embodiment 2, the active suspension is subjected to solid-liquid separation. Then, a mixture of aggregate and calcium source is obtained using one of the separated aluminosilicate activated particles, or using the other separated aluminosilicate sol, or using both the separated aluminosilicate activated particles and the other aluminosilicate sol. Even when both are used, the ratio of aluminosilicate activated particles to aluminosilicate sol may differ from that of the active suspension in the manufacturing method of the hardened body of Embodiment 1. Since both the aluminosilicate activated particles and the aluminosilicate sol constituting the active suspension are active and can react with the calcium source to obtain a high-strength hardened body, a mixture of aggregate and calcium source is obtained using either or both of the aluminosilicate activated particles and the aluminosilicate sol constituting the active suspension, and finally a hardened body is obtained. The resulting hardened material, like the hardened material of Embodiment 1, can achieve a specific strength of approximately 10 to 75 Nm / g, exhibiting superior properties compared to ordinary concrete, and is considered suitable for applications such as buildings.

[0058] In the step of obtaining a mixture of aluminosilicate-activated particles and / or aluminosilicate sol, aggregate and calcium source, in the method for producing a hardened body of Embodiment 2, it is preferable that the aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, and that the aluminosilicate-activated particles are 10 to 140 parts by mass or the aluminosilicate sol is 10 to 70 parts by mass or the total of the aluminosilicate-activated particles and aluminosilicate sol is 10 to 150 parts by mass per 100 parts by mass of the aggregate and calcium source.

[0059] The aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, as in Embodiment 1. When aluminosilicate-activated particles are used in the mixture, if the aluminosilicate-activated particles are 10% by mass or less per 100 parts by mass of the total aggregate and calcium source, the desired strength cannot be obtained due to insufficient binder. If it is 140 parts by mass or more, the moisture content becomes high and demolding becomes difficult. Preferably, the aluminosilicate-activated particles are 20 to 100 parts by mass per 100 parts by mass of the total aggregate and calcium source.

[0060] When using aluminosilicate sol in a mixture, if the aluminosilicate sol is 10 parts by mass or less per 100 parts by mass of aggregate and calcium source combined, the desired strength cannot be obtained due to insufficient binder. If it is 70 parts by mass or more, the moisture content becomes high, making demolding difficult. Preferably, the aluminosilicate sol is 20 to 80 parts by mass per 100 parts by mass of aggregate and calcium source combined.

[0061] When using both aluminosilicate-activated particles and aluminosilicate sol in a mixture, if the total amount of aluminosilicate-activated particles and aluminosilicate sol is 10 parts by mass or less per 100 parts by mass of aggregate and calcium source, the desired strength cannot be obtained due to insufficient binder. If it is 150 parts by mass or more, the moisture content becomes high, making demolding difficult. Preferably, the total amount of aluminosilicate-activated particles and aluminosilicate sol is 20 to 100 parts by mass per 100 parts by mass of aggregate and calcium source.

[0062] (Embodiment 3) The method for producing a hardened body according to Embodiment 3 of the present invention comprises the steps of: heating and mixing volcanic glass derived from volcanic ejecta with an alkaline solution to obtain an activated suspension by adding an inorganic acid; obtaining a mixture of dealkaliated aluminosilicate activated particles, aggregate and calcium source, obtained by solid-liquid separation of the activated suspension and aluminosilicate activated particles from which the alkaline component has been reduced; and filling the mixture into a mold, molding it, demolding and curing it.

[0063] The manufacturing method for the cured body of Embodiment 3 differs from that of Embodiment 1 in that Embodiment 1 includes a step of obtaining a mixture of an active suspension, aggregate, and calcium source, whereas Embodiment 3 includes a step of obtaining a mixture of dealkaliated aluminosilicate activated particles, aggregate, and calcium source, obtained by solid-liquid separation of the active suspension and aluminosilicate activated particles, from which the alkaline component has been reduced. All other steps are the same. Therefore, in the description of the manufacturing method for the cured body of Embodiment 3 described below, matters that overlap with those described in the manufacturing method for the cured body of Embodiment 1 will be referred to in the description of the manufacturing method for the cured body of Embodiment 1, and redundant descriptions will be omitted.

[0064] In the manufacturing method of the hardened body of Embodiment 1, a mixture of aggregate and calcium source was obtained by using the active suspension as is. However, in the manufacturing method of the hardened body of Embodiment 3, a mixture of aggregate and calcium source is obtained using dealkalized aluminosilicate activated particles, which are obtained by reducing the alkali component from aluminosilicate activated particles obtained by solid-liquid separation of the active suspension. The aluminosilicate activated particles constituting the active suspension are active and can react with the calcium source to obtain a high-strength hardened body. Moreover, since the aluminosilicate activated particles are subjected to a treatment to reduce the alkali component to become dealkalized aluminosilicate activated particles, a hardened body with high durability can be obtained. The obtained hardened body can obtain a specific strength of about 10 to 75 Nm / g, similar to the hardened body of Embodiment 1, and has superior properties that are higher than ordinary concrete, making it suitable for use in buildings and the like.

[0065] The alkaline component can be reduced from aluminosilicate-activated particles by suspending them in water and performing centrifugation or natural sedimentation, either alone or repeatedly.

[0066] In the step of obtaining a mixture of dealkaliated aluminosilicate activated particles, aggregate, and calcium source in the method for producing a hardened body of Embodiment 3, it is preferable that the aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, and that the amount of dealkaliated aluminosilicate activated particles is 10 to 150 parts by mass per 100 parts by mass of the total aggregate and calcium source.

[0067] The aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, as in Embodiment 1. If the amount of dealkaliated aluminosilicate activated particles is 10% by mass or less, the desired strength cannot be obtained due to insufficient binder. If it is 150 parts by mass or more, the moisture content becomes high and demolding becomes difficult. Preferably, the amount of dealkaliated aluminosilicate activated particles is 20 to 100 parts by mass per 100 parts by mass of the total aggregate and calcium source. [Examples]

[0068] Next, the present invention will be described in more detail by comparing the examples with comparative examples, but the present invention is not limited in any way by these examples.

[0069] Comparative Examples 1-4 are examples in which the raw materials were not subjected to alkali-acid treatment, which involves heating and mixing the raw materials with an alkaline solution and then adding an inorganic acid.

[0070] (Comparative Example 1) A molded body was obtained by mixing 100 parts by mass of 75 parts by mass of lava fine powder with an average particle size of 0.095 mm, obtained by grinding lava from Sakurajima, with 25 parts of calcium hydroxide, and then mixing this mixture with 19 parts by mass of water at a molding pressure of 226 MPa. The molded body was dried at 100°C for 14 hours to obtain a hardened body. The compressive strength was measured using a Shimadzu AG-100KNA, and it was found to be 35.8 MPa. The density of the hardened body was 2.1 g / cm³. 3 The specific intensity obtained by dividing by was 16.8 Nm / g. After curing in 20°C water for 14 days, the compressive strength was 18.5 MPa, the specific strength was 9.5 Nm / g, and the improvement in specific strength relative to the initial strength decreased by 43.5%, indicating no strength improvement was observed during underwater curing. After curing for 7 days in an atmosphere containing 100 vol% carbon dioxide, the weight increase rate was 6.8%, the compressive strength was 69.8 MPa, the specific strength was 31.0 Nm / g, and the improvement rate of specific strength relative to the initial strength was 84.3%.

[0071] (Comparative Example 2) For the hardened body obtained by replacing the lava powder of Comparative Example 1 with silica sand (from Toyoura) and 19 parts by mass of water with 15 parts by mass, the specific strength, determined in the same manner as for Comparative Example 1, was 15.3 Nm / g. The rate of improvement in specific strength after underwater curing decreased by 74.1%, indicating no strength improvement was observed during underwater curing. The weight increase rate after carbon dioxide curing was 6.4%, and the specific strength improvement rate was 37.9%.

[0072] (Comparative Example 3) For the hardened body obtained by replacing the lava powder of Comparative Example 1 with crushed lime sand (from Oita Prefecture) and 19 parts by mass of water with 15 parts by mass, the specific strength, determined in the same manner as for Comparative Example 1, was 20.1 Nm / g. The rate of improvement in specific strength after underwater curing decreased by 43.0%, indicating no strength improvement was observed during underwater curing. The weight increase rate after carbon dioxide curing was 6.1%, and the specific strength improvement rate was 93.2%.

[0073] (Comparative Example 4) For a hardened body obtained using the same process as in Comparative Example 1, with 100 parts by weight of calcium hydroxide and 26 parts by weight of water, the specific strength, as determined in the same manner as in Comparative Example 1, was 15.5 Nm / g. The rate of improvement in specific strength after underwater curing decreased by 23.2%, indicating no strength improvement was observed during underwater curing. The weight increase rate after carbon dioxide curing was 24.9%, and the specific strength improvement rate was 169.5%.

[0074] (Example 1) 4 g of lava powder with a particle size of 0.095 mm was added to 24 mL of 2 mol / L sodium hydroxide aqueous solution and heated and stirred at 98°C for 4 hours under atmospheric pressure. Then, while heating to 80°C, 8 mL of 3.6 mol / L sulfuric acid was added to obtain an active suspension with a pH of 2. This activated suspension was filtered through 5B filter paper to obtain aluminosilicate activated particles with a solid content of 70% and aluminosilicate sol with a solid content of 11% by mass. 74 parts by mass of lava fine powder were mixed with 3 parts by mass of aluminosilicate activated particles and 26 parts by mass of aluminosilicate sol, and then 26 parts of calcium hydroxide were added to obtain a mixture. The mixture was filled into a mold and molded under a pressure of 226 MPa while dewatering to obtain a hardened body. The specific strength, determined in the same manner as in Comparative Example 1, was 17.8 Nm / g. The improvement in specific strength after curing in water was 82.7%. The weight increase rate after carbon dioxide curing was 6.9%, and the specific strength improvement rate was 102.5%.

[0075] (Example 2) Eight g of volcanic glass fine powder, obtained by grinding 0.084 mm particle size volcanic glass granules (volcanic glass content 88%) obtained by dry-gravity separation from volcanic ejecta (shirasu), was added to 48 mL of 1 mol / L sodium hydroxide aqueous solution. The mixture was heated and stirred at 98°C for 4 hours and 30 minutes under atmospheric pressure, and then 8.6 mL of 3.6 mol / L sulfuric acid was added while heating to 80°C to obtain an active suspension with a pH of 3.5. This activated suspension was centrifuged at 3000 rpm for 30 minutes to obtain aluminosilicate activated particles with a solid content of 33% by mass and aluminosilicate sol with a solid content of 11% by mass. Following the process for obtaining the mixture and hardened body of Example 1, 72 parts by mass of silica sand (from Toyoura), 42 parts by mass of aluminosilicate activated particles, and 28 parts by mass of calcium hydroxide were mixed to obtain a hardened body. The specific strength of the hardened body, determined in the same manner as in Comparative Example 1, was 19.2 Nm / g. The improvement in specific strength after curing in water was 36.2%. The weight increase rate after carbon dioxide curing was 8.3%, and the specific strength improvement rate was 45.6%.

[0076] (Example 3) In Example 2, 15 parts by mass of aluminosilicate sol obtained by centrifugation, 75 parts by mass of crushed lime sand (from Oita Prefecture), and 25 parts by mass of calcium hydroxide were mixed in the same manner as in Example 1 to obtain a hardened body. The specific strength, determined in the same manner as in Comparative Example 1, was 16.1 Nm / g. The improvement in specific strength after curing in water was 10.9%. The weight increase rate after carbon dioxide curing was 7.0%, and the specific strength improvement rate was 123.1%.

[0077] (Example 4) In Example 2, 56 parts by mass of aluminosilicate sol obtained by centrifugation, 50 parts by mass of slaked lime as aggregate, and 50 parts by mass of calcium hydroxide as a calcium source were mixed in the same manner as in Example 1, and a hardened body was obtained by molding at a pressure of 38 MPa. The specific strength, determined in the same manner as in Comparative Example 1, was 7.3 Nm / g, the specific strength improvement rate after curing in water was 98.8%, the weight increase rate after curing with carbon dioxide was 31.2%, and the specific strength improvement rate was 422.3%.

[0078] (Example 5) In Example 2, 42 parts by mass of aluminosilicate-activated particles obtained by centrifugation, 36 parts by mass of aluminosilicate sol, 72 parts by mass of shirasu balloons (SKB-9000, manufactured by Toyowa Co., Ltd.), and 28 parts by mass of calcium hydroxide were mixed in the same manner as in Example 1, and a hardened body was obtained by molding at a pressure of 75 MPa. The specific strength, determined in the same manner as in Comparative Example 1, was 15.7 Nm / g. The improvement in specific strength after curing in water was 18.3%. The weight increase rate after carbon dioxide curing was 7.8%.

[0079] (Example 6) Four g of volcanic glass granules derived from Shirasu, with a particle size of 0.084 mm and a volcanic glass content of 88%, were added to 24 mL of a 1 mol / L sodium hydroxide aqueous solution. The mixture was heated and stirred at 98°C for 4 hours under atmospheric pressure, and then 4.5 mL of 3.6 mol / L sulfuric acid was added while heating to 80°C to obtain an active suspension with a pH of 3 and a solid content of 15% by mass. In the process of obtaining the mixture and cured body of Example 1, the cured body was obtained in the same manner as in Example 1, except that 75 parts by mass of volcanic glass granules, 24 parts by mass of the active suspension, and 25 parts by mass of calcium hydroxide were used. Its specific strength was 9.8 Nm / g. The improvement in specific strength after curing in water was 145.4%. The weight increase rate after carbon dioxide curing was 7.1%, and the specific strength improvement rate was 103.6%.

[0080] (Example 7) The active suspension obtained in Example 6 was left to stand for a certain period of time, and the supernatant was separated to obtain an aluminosilicate sol with a solid content of 11% by mass. In the process of obtaining the mixture and cured body of Example 1, the cured body was obtained in the same manner as in Example 1, except that 75 parts by mass of volcanic glass granules, 25 parts by mass of aluminosilicate sol, and 25 parts by mass of calcium hydroxide were used. Its specific strength was 9.8 Nm / g. The improvement in specific strength after curing in water was 224.0%. The weight increase rate after carbon dioxide curing was 7.4%, and the specific strength improvement rate was 101.3%.

[0081] (Example 8) The cured body obtained in Example 7 was autoclaved at 100°C for 14 hours under saturated water vapor pressure. The specific strength obtained in the same manner as in Comparative Example 1 was 32.8 Nm / g, and the improvement rate of specific strength compared to the initial specific strength of 9.8 Nm / g obtained in Example 7 was 236.8%.

[0082] (Example 9) In the process of obtaining the active suspension of Example 6, the amount of sulfuric acid was replaced with 5 mL to obtain an active suspension with a pH of 3. The active suspension was filtered using 5B filter paper to obtain aluminosilicate activated particles with a solid content of 73% by mass and aluminosilicate sol with a solid content of 11% by mass. In the process of obtaining the mixture and cured body of Example 1, the cured body was obtained in the same manner as in Example 1, except that 73 parts by mass of volcanic glass granules, 8 parts by mass of aluminosilicate activated particles, and 27 parts by mass of aluminosilicate sol were used. Its specific strength was 16.4 Nm / g. The specific strength improvement rate after underwater curing was 140.7%, the weight increase rate after carbon dioxide curing was 8.5%, and the specific strength improvement rate was 104.8%.

[0083] (Example 10) 8 g of volcanic glass fine powder derived from Shirasu, with a particle size of 0.007 mm and a volcanic glass content of 87%, was added to 24 mL of 2 mol / L sodium hydroxide aqueous solution. The mixture was heated and stirred at 98°C for 5 hours under atmospheric pressure, and then 4.5 mL of 3.6 mol / L sulfuric acid was added while heating to 80°C to obtain an active suspension with a pH of 4. This active suspension was centrifuged at 3000 rpm for 30 minutes to obtain aluminosilicate-activated particles with a solid content of 29% by mass. In the process of obtaining the mixture and cured body of Example 1, the cured body was obtained in the same manner as in Example 1, except that 60 parts by mass of volcanic glass granules, 80 parts by mass of aluminosilicate activated particles, and 40 parts by mass of calcium hydroxide were used. Its specific strength was 21.8 Nm / g. The improvement in specific strength after curing in water was 91.4%. The weight increase rate after carbon dioxide curing was 10.5%, and the specific strength improvement rate was 29.1%.

[0084] (Example 11) In Example 2, the aluminosilicate-activated particles obtained by centrifugation were mixed with 10 times the amount of distilled water and stirred. This process of centrifugation at 3000 rpm for 30 minutes was repeated twice to obtain dealkaliated aluminosilicate-activated particles with a solid content of 18% by mass. In the process of obtaining the mixture and hardened body of Example 1, the hardened body was obtained in the same manner as in Example 1, except that 72 parts by mass of volcanic glass granules, 42 parts by mass of dealkaliated aluminosilicate-activated particles, and 28 parts by mass of calcium hydroxide were used. Its specific strength was 19.1 Nm / g. The improvement in specific strength after curing in water was 116.8%. The weight increase rate after carbon dioxide curing was 9.1%, and the specific strength improvement rate was 57.5%.

[0085] (Example 12) The cured body obtained in Example 10 was autoclaved at 100°C for 14 hours under saturated water vapor pressure. The specific strength, determined in the same manner as in Comparative Example 1, was 35.9 Nm / g, and the improvement in specific strength compared to the initial specific strength of 21.8 Nm / g obtained in Example 10 was 64.9%.

[0086] (Example 13) 25 parts by mass of aluminosilicate sol obtained by filtration in Example 1, 75 parts by mass of lava fine powder, and 25 parts by mass of calcium hydroxide were mixed in the same manner as in Example 1 to obtain a hardened body. The specific strength, determined in the same manner as in Comparative Example 1, was 15.7 Nm / g. The improvement in specific strength after curing in water was 74.1%. The weight increase rate after carbon dioxide curing was 6.6%, and the specific strength improvement rate was 116.7%.

[0087] (Example 14) In Example 2, 42 parts by mass of aluminosilicate-activated particles obtained by centrifugation, 72 parts by mass of fine sand dry-separated by specific gravity from volcanic ash, and 28 parts by mass of calcium hydroxide were mixed in the same manner as in Example 1 to obtain a hardened body. The specific strength, determined in the same manner as in Comparative Example 1, was 20.5 Nm / g. The improvement in specific strength after curing in water was 25.0%. The weight increase rate after carbon dioxide curing was 7.5%, and the specific strength improvement rate was 17.0%.

[0088] (Example 15) In Example 2, 41 parts by mass of aluminosilicate-activated particles obtained by centrifugation were mixed with 50 parts by mass of calcium hydroxide as aggregate and 50 parts by mass of calcium hydroxide as a calcium source in the same manner as in Example 1, and a hardened body was obtained by molding at a pressure of 75 MPa. The specific strength, determined in the same manner as in Comparative Example 1, was 11.3 Nm / g. The improvement in specific strength after curing in water was 75.4%. The weight increase rate after carbon dioxide curing was 29.1%, and the specific strength improvement rate was 557.3%.

[0089] (Example 16) In the process of obtaining the active suspension of Example 2, the volcanic glass fine powder was replaced with Sakurajima volcanic ash with a particle size of 0.34 mm to obtain an active suspension with a pH of 1.5. This activated suspension was centrifuged at 3000 rpm for 30 minutes to obtain aluminosilicate-activated particles with a solid content of 36% by mass. In the process of obtaining the mixture and hardened body of Example 1, the hardened body was obtained in the same manner as in Example 1, except that 72 parts by mass of volcanic ash, 42 parts by mass of aluminosilicate activated particles, and 28 parts by mass of calcium hydroxide were used. Its specific strength was 25.3 Nm / g. The weight increase rate after carbon dioxide curing was 7.4%, and the specific strength improvement rate was 34.6%.

[0090] (Example 17) In the process of obtaining the active suspension of Example 2, 8 g of volcanic glass fine powder was replaced with 4 g of driftwood collected from Okinoerabu Island to obtain an active suspension with a pH of 2.5. This activated suspension was centrifuged at 3000 rpm for 30 minutes to obtain aluminosilicate activated particles with a solid content of 30% by mass and aluminosilicate sol with a solid content of 11% by mass. In the process of obtaining the mixture and cured body of Example 1, the cured body was obtained in the same manner as in Example 1, except that 75 parts by mass of volcanic glass granules, 37 parts by mass of aluminosilicate activated particles, 25 parts by mass of aluminosilicate sol, and 25 parts by mass of calcium hydroxide were used. Its specific strength was 11.5 Nm / g. The improvement in specific strength after curing in water was 80.3%. The weight increase rate after carbon dioxide curing was 6.3%, and the specific strength improvement rate was 53.0%.

[0091] (Example 18) In Example 2, 41 parts by mass of aluminosilicate-activated particles obtained by centrifugation, 50 parts by mass of volcanic glass granules, and 50 parts by mass of ordinary Portland cement (manufactured by Sumitomo Osaka Cement Co., Ltd.) were mixed in the same manner as in Example 1 to obtain a hardened body. The specific strength, determined in the same manner as in Comparative Example 1, was 21.5 Nm / g. The improvement in specific strength after curing in water was 220.1%. The weight increase rate after carbon dioxide curing was 12.6%, and the specific strength improvement rate was 79.0%.

[0092] (Example 19) Four g of volcanic glass fine powder derived from Shirasu, with a particle size of 0.007 mm and a volcanic glass content of 87%, was added to 24 mL of 1 mol / L sodium hydroxide aqueous solution. The mixture was heated and stirred at 98°C for 4 hours and 30 minutes under atmospheric pressure, and then 0.8 mL of 3.6 mol / L sulfuric acid was added while heating to 80°C to obtain an active suspension with a pH of 10.5. This active suspension was centrifuged at 3000 rpm for 30 minutes to obtain an aluminosilicate sol with a solid content of 11% by mass. In the process of obtaining the mixture and hardened body of Example 1, the hardened body was obtained in the same manner as in Example 1, except that 75 parts by mass of crushed lime sand, 16 parts by mass of aluminosilicate sol, and 25 parts by mass of calcium hydroxide were used. Its specific strength was 20.4 Nm / g. The weight increase rate after carbon dioxide curing was 7.5%, and the specific strength improvement rate was 99.1%.

[0093] (Example 20) In Example 2, 41 parts by mass of aluminosilicate-activated particles obtained by centrifugation, 20 parts by mass of volcanic glass granules, and 80 parts by mass of calcium hydroxide were mixed in the same manner as in Example 1, and a hardened body was obtained by molding at a pressure of 75 MPa. The specific strength, determined in the same manner as in Comparative Example 1, was 23.4 Nm / g. The improvement in specific strength after curing in water was 6.3%. The weight increase rate after carbon dioxide curing was 23.9%, and the specific strength improvement rate was 83.2%.

[0094] (Example 21) In Example 2, 41 parts by mass of aluminosilicate-activated particles obtained by centrifugation, 85 parts by mass of volcanic glass granules, and 15 parts by mass of calcium hydroxide were mixed in the same manner as in Example 1 to obtain a hardened body. The specific strength, determined in the same manner as in Comparative Example 1, was 12.5 Nm / g. The improvement in specific strength after curing in water was 92.2%. The weight increase rate after carbon dioxide curing was 4.0%, and the specific strength improvement rate was 5.2%.

[0095] (Example 22) 20.1 g of volcanic glass granules derived from Shirasu, with a particle size of 0.084 mm and a volcanic glass content of 88%, were added to 60 mL of a 2 mol / L sodium hydroxide aqueous solution. The mixture was heated and stirred at 98°C under atmospheric pressure for 4 hours, and then 24.9 mL of 3.6 mol / L sulfuric acid was added while heating to 80°C to obtain an active suspension with a pH of 3. This activated suspension was centrifuged at 3000 rpm for 30 minutes to obtain aluminosilicate-activated particles with a solid content of 30% by mass. In the process of obtaining the mixture and cured body of Example 1, the cured body was obtained in the same manner as in Example 1, except that 69 parts by mass of volcanic glass granules, 23 parts by mass of aluminosilicate activated particles, and 31 parts by mass of calcium hydroxide were used. Its specific strength was 23.0 Nm / g. The improvement in specific strength after curing in water was 80.7%. The weight increase rate after carbon dioxide curing was 5.6%, and the specific strength improvement rate was 17.4%.

[0096] (Example 23) In Example 2, 140 parts by mass of aluminosilicate-activated particles obtained by centrifugation, 65 parts by mass of volcanic glass granules, and 35 parts by mass of calcium hydroxide were mixed in the same manner as in Example 1 to obtain a hardened body. The specific strength, determined in the same manner as in Comparative Example 1, was 24.1 Nm / g. The improvement in specific strength after curing in water was 43.4%. The weight increase rate after carbon dioxide curing was 9.0%.

[0097] (Example 24) 8 g of volcanic glass fine powder derived from Shirasu, with a particle size of 0.007 mm and a volcanic glass content of 87%, was added to 24 mL of 2 mol / L sodium hydroxide aqueous solution. The mixture was heated and stirred at 98°C for 5 hours under atmospheric pressure, and then 9 mL of 3.6 mol / L sulfuric acid was added while heating to 80°C to obtain an active suspension with a pH of 4. This activated suspension was centrifuged at 3000 rpm for 30 minutes to obtain aluminosilicate activated particles with a solid content of 29% by mass and aluminosilicate sol with a solid content of 11% by mass. In the process of obtaining the mixture and cured body of Example 1, the specific strength of the cured body obtained by mixing 73 parts by mass of volcanic glass granules, 11 parts by mass of aluminosilicate activated particles, 12 parts by mass of aluminosilicate sol, and 27 parts by mass of calcium hydroxide was 15.9 Nm / g, as determined in the same manner as in Comparative Example 1, and the specific strength improvement rate after curing in water was 120.7%. The weight increase rate after carbon dioxide curing was 7.9%, and the specific strength improvement rate was 62.0%.

[0098] (Example 25) Volcanic ash from Izu Oshima, which has a composition similar to regolith (lunar rock), was used as a raw material and aggregate to obtain the activated suspension. Therefore, instead of the volcanic glass fine powder used in the process of obtaining the activated suspension in Example 2, Izu Oshima volcanic ash with a particle size of 0.38 mm was used to obtain an activated suspension with a pH of 4. This activated suspension was centrifuged at 3000 rpm for 30 minutes to obtain aluminosilicate-activated particles with a solid content of 42% by mass. In the process of obtaining the mixture and hardened body of Example 1, the hardened body was obtained in the same manner as in Example 1, except that 72 parts by mass of Izu Oshima volcanic ash, 51 parts by mass of aluminosilicate activated particles, and 28 parts by mass of calcium hydroxide were used. Its specific strength was 19.4 Nm / g.

Claims

1. A process to obtain an active suspension by heating and mixing volcanic glass granules or glass powder derived from volcanic ejecta with an alkaline solution of sodium hydroxide at a concentration of 0.5 to 3 mol / l at a heating temperature of 80 to 100°C, and further adding sulfuric acid as an inorganic acid so that the pH after addition is pH 1 to 11. A step of obtaining a mixture of the activated suspension, aggregate, and calcium source, The process involves filling the aforementioned mixture into a mold, molding it, demolding it, and curing it. It has, A method for producing a cured product, characterized in that the active suspension contains aluminosilicate activating particles and aluminosilicate sol.

2. In the process of obtaining a mixture of the activated suspension, aggregate, and calcium source, The method for producing a hardened product according to claim 1, characterized in that the aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, and the active suspension is 10 to 110 parts by mass per 100 parts by mass of the aggregate and calcium source combined.

3. A process to obtain an active suspension by heating and mixing volcanic glass granules or glass powder derived from volcanic ejecta with an alkaline solution of sodium hydroxide at a concentration of 0.5 to 3 mol / l at a heating temperature of 80 to 100°C, and further adding sulfuric acid as an inorganic acid so that the pH after addition is pH 1 to 11. A step of obtaining a mixture of aluminosilicate-activated particles and aluminosilicate sol, or both, obtained by solid-liquid separation of the activated suspension, aggregate, and calcium source. The process involves filling the aforementioned mixture into a mold, molding it, demolding, and curing it. A method for producing a cured body having the following characteristics.

4. In the process of obtaining a mixture of either or both of the aluminosilicate activated particles and / or aluminosilicate sol, aggregate and calcium source, The method for producing a cured body according to claim 3, characterized in that the aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, and the amount of aluminosilicate-activated particles is 10 to 140 parts by mass or aluminosilicate sol is 10 to 70 parts by mass or the total amount of aluminosilicate-activated particles and aluminosilicate sol is 10 to 150 parts by mass per 100 parts by mass of aggregate and calcium source combined.

5. A process to obtain an active suspension by heating and mixing volcanic glass granules or glass powder derived from volcanic ejecta with an alkaline solution of sodium hydroxide with a concentration of 0.5 to 3 mol / l at a heating temperature of 80 to 100°C, and further adding sulfuric acid as an inorganic acid so that the pH after addition is pH 1 to 11. A step of obtaining a mixture of alkalinized aluminosilicate-activated particles obtained by solid-liquid separation of the activated suspension, aggregate, and calcium source, by treating the alkaline component to reduce the alkalinity of the aluminosilicate-activated particles, The process involves filling the aforementioned mixture into a mold, molding it, demolding, and curing it. A method for producing a cured body having the following characteristics.

6. In the process of obtaining a mixture of the aforementioned alkalinized aluminosilicate activated particles, aggregate, and calcium source, The method for producing a hardened body according to claim 5, characterized in that the aggregate / calcium source ratio, which is the mass ratio of aggregate to calcium source, is 0.2 to 6.0, and the amount of dealkaliated aluminosilicate activated particles is 10 to 150 parts by mass per 100 parts by mass of the total of aggregate and calcium source.

7. The method for producing a hardened body according to any one of claims 1 to 6, characterized in that the volcanic glass material is volcanic glass granules with a volcanic glass content of 80% by mass or more, which are classified from volcanic ejecta, or volcanic glass fine powder obtained by crushing the volcanic glass granules.

8. The volcanic glass material is characterized in that it is volcanic glass granules obtained by classifying volcanic ash or volcanic rock, or volcanic glass fine powder obtained by grinding or pulverizing the volcanic glass granules. A method for producing a cured product as described in any of the six from to the present.

9. The method for producing a cured product according to any one of claims 1 to 8, characterized in that the aluminosilicate-activated particles (including dealkalized aluminosilicate-activated particles) are particles having a surface covered with aluminosilicate gel, with a nucleus consisting of either or both of volcanic glass granules or glass powder and zeolite, and the aluminosilicate gel dissolves from the nucleus and forms an active layer on the particle surface.

10. The method for producing a cured body according to any one of claims 1 to 4 or any one of claims 5 to 6, characterized in that the aluminosilicate sol is a colloidal solution in which particles mainly composed of aluminosilicate containing components of volcanic glass fine particles or glass powder are dispersed, and the solid content concentration is 10 to 20% by mass.

11. A method for producing a cured article according to any one of claims 1 to 7, characterized in that the calcium source is a compound that releases calcium ions under wet conditions.

12. A method for producing a cured body according to any one of claims 1 to 11, characterized in that, in the step of filling the mixture into a mold and molding it, the molding pressure is 30 to 230 MPa and dehydration is performed during molding.

13. A method for producing a cured body according to any one of claims 1 to 12, characterized in that the process of filling the mixture into a mold, molding it, demolding it, and curing it is carried out in an atmosphere containing carbon dioxide.

14. A method for producing a cured body according to any one of claims 1 to 12, characterized in that the mixture is filled into a mold, molded, demolded, and cured in water during the curing process.

15. A method for producing a cured body according to any one of claims 1 to 12, characterized in that the mixture is filled into a mold, molded, demolded, and cured in a pressurized steam atmosphere.

16. A method for producing a cured article according to any one of claims 1 to 15, characterized in that the specific strength of the cured article is 10 to 75 Nm / g.

17. The method for producing a hardened body according to any one of claims 1 to 16, characterized in that the aggregate is volcanic glass fine grains with a volcanic glass content of 80% or more obtained by dry specific gravity separation from volcanic ejecta (shirasu), or volcanic glass fine grains obtained by classifying volcanic ash or volcanic rock produced by the rapid cooling of magma.

18. A method for producing a hardened body according to any one of 1 to 16, characterized in that the aggregate is volcanic glass fine grains with a volcanic glass content of 80% or more obtained by dry specific gravity separation from shirasu, a volcanic ejecta, or a calcined foam called shirasu balloon or perlite, obtained by calcining and foaming volcanic glass fine grains obtained by classifying volcanic ash or volcanic rock produced by the rapid cooling of magma.

19. A method for producing a hardened body according to any one of claims 1 to 16, characterized in that the aggregate is slaked lime.

20. A method for producing a cured body according to any one of claims 1 to 19, wherein the step of obtaining the mixture comprises a primary mixing step of mixing raw materials other than the calcium source, and a secondary mixing step of further adding the calcium source to obtain the mixture.