Hydraulic components, hardeners, and methods for manufacturing hydraulic components

Abstract

To provide a hydraulic composition that contains inorganic minerals other than kaolin, yet reduces auto-shrinkage and exhibits sufficient strength development. [Solution] The hydraulic composition contains an inorganic mineral and / or its calcined form containing at least one of allophane and halloysite, cement clinker, and gypsum. In the hydraulic composition, based on the total amount of the inorganic mineral and / or its calcined form, cement clinker, and gypsum, the content of the inorganic mineral and / or its calcined form is 10 to 70% by mass, and the total content of cement clinker and gypsum is 30 to 90% by mass, and based on the total mass of the hydraulic composition, the SO3 equivalent content of gypsum is 1.5% by mass or more.

Description

[Technical Field]

[0001] This disclosure relates to hydraulic compositions, hardened bodies, and methods for producing hydraulic compositions. [Background technology]

[0002] LC3 (Limestone Calcined Clay Cement) is a known technology that involves calcining inorganic minerals to increase their reactivity and using them as a substitute for cement admixtures such as blast furnace slag and fly ash (see, for example, Non-Patent Document 1). This cement can be called a low-carbon cement, and compared to ordinary Portland cement, it can reduce carbon dioxide emissions (CO2) associated with its production.

[0003] Non-patent document 1 shows that, with respect to LC3, good strength development can be achieved with materials containing meta-kaolin, which is obtained by calcining kaolin as an inorganic mineral. However, since the regions and countries where kaolin is produced are limited, the search for alternative materials to kaolin remains a challenge. For example, cement mixtures using allophane as an alternative material to kaolin are being considered (Patent document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-142912 [Non-patent literature]

[0005] [Non-Patent Document 1] Karen Scrivener et al.: Calcined clay limestone cements (LC3), Cement and Concrete Research,Vol.114,pp.49-56 (2018) [Overview of the project] [Problems that the invention aims to solve]

[0006] Our investigations have revealed that concrete manufactured using the cement mixture described above tends to undergo autologous shrinkage. Reducing the autologous shrinkage of concrete is expected to improve its durability.

[0007] This disclosure is made in view of the above circumstances and aims to provide a hydraulic composition that contains inorganic minerals other than kaolin, yet reduces auto-shrinkage and exhibits sufficient strength development. This disclosure also aims to provide a hardened body obtained from the hydraulic composition and a method for producing the hydraulic composition. [Means for solving the problem]

[0008] One aspect of this disclosure provides a hydraulic composition comprising an inorganic mineral and / or its calcined product containing at least one of allophane and halloysite, cement clinker, and gypsum. In the hydraulic composition, the content of the inorganic mineral and / or its calcined product is 10 to 70% by mass, and the total content of cement clinker and gypsum is 30 to 90% by mass, based on the total amount of the inorganic mineral and / or its calcined product, cement clinker, and gypsum. The SO3 content of the gypsum is 1.5% by mass or more, based on the total mass of the hydraulic composition.

[0009] Although the mechanism is not clear, the above hydraulic composition contains predetermined amounts of an inorganic mineral containing at least one of allophane and halloysite, cement clinker, and gypsum, thereby contributing to CO2 reduction, reducing auto-shrinkage, and exhibiting sufficient strength development. [Effects of the Invention]

[0010] According to this disclosure, it is possible to provide a hydraulic composition that contains inorganic minerals other than kaolin, yet reduces auto-shrinkage and exhibits sufficient compressive strength. This disclosure also provides a hardened body obtained from the hydraulic composition and a method for producing the hydraulic composition. [Modes for carrying out the invention]

[0011] Preferred embodiments of this disclosure are described in detail below. However, this disclosure is not limited to the embodiments described below. In the following description, when "X~Y" (where X and Y are any numbers) is written, it means "X or more and Y or less" unless otherwise specified. Unless otherwise specified, the materials exemplified in this specification can be used individually or in combination of two or more.

[0012] <Hydraulic composition> The hydraulic composition contains an inorganic mineral and / or its calcined form containing at least one of allophane and halloysite, cement clinker, and gypsum. In the hydraulic composition, based on the total amount of the inorganic mineral and / or its calcined form, cement clinker, and gypsum, the content of the inorganic mineral and / or its calcined form is 10 to 70% by mass, and the total content of cement clinker and gypsum is 30 to 90% by mass. Based on the total mass of the hydraulic composition, the SO3 equivalent content of gypsum is 1.5% by mass or more.

[0013] (Inorganic minerals) Inorganic minerals may be minerals produced by the weathering of volcanic ejecta, i.e., minerals derived from volcanic ejecta. Examples of volcanic ejecta include volcanic ash, volcanic lapilli, pumice, and pyroclastic flow deposits. Inorganic minerals may also be minerals produced by the weathering of igneous rocks. Examples of igneous rocks include granite. Generally, allophane is produced by the weathering of volcanic ejecta or igneous rocks, halloysite is produced by further weathering of allophane, and kaolin is produced by further weathering of halloysite. Kaolin, allophane, and halloysite are clay minerals.

[0014] The inorganic mineral contained in the hydraulic composition of the present disclosure includes at least one selected from the group consisting of allophane and halloysite. Allophane generally has a particle size of 0.05 to 0.2 μm, and 250 to 600 m 2 / g BET specific surface area. Halloysite is a crystalline inorganic mineral. Halloysite generally has a particle size of 0.1 to 0.3 μm, and 40 to 100 m 2 / g BET specific surface area. From the viewpoint of enhancing reactivity with cement clinker, the inorganic mineral preferably contains allophane. Allophane is an amorphous inorganic mineral. Examples of the inorganic mineral containing allophane include Kanuma soil, Andosol, Satsuma soil, and Sekado P1 (trade name, manufactured by Shinagawa General Co., Ltd.), and the like.

[0015] In the present disclosure, the simple reference to "inorganic mineral" includes those in various forms such as massive and granular forms, pulverized products obtained by pulverizing massive matters or particles, aggregates formed by agglomerated particles, and granulated products, etc.

[0016] From the viewpoint of easily exhibiting sufficient compressive strength, the content of allophane or halloysite in the inorganic mineral is preferably 30% by mass or more, more preferably 40% by mass or more, still more preferably 60% by mass or more, even more preferably 80% by mass or more, and may be 100% by mass (an inorganic mineral substantially consisting of allophane or halloysite).

[0017] The content of allophane in the inorganic mineral can be measured by an acid-alkali alternating dissolution method, and the content of halloysite in the inorganic mineral can be measured by XRD Rietveld analysis.

[0018] The inorganic mineral may contain other inorganic minerals besides allophane and halloysite. As other inorganic minerals, imogolite, illite, montmorillonite, pyrophyllite and the like may be contained. Kaolin does not need to be contained.

[0019] Calcified inorganic minerals (hereinafter also referred to as "calcined inorganic minerals") are obtained by calcining inorganic minerals under conditions in which at least a portion of the crystalline structure of allophane or halloysite collapses, but does not completely change into another crystalline structure such as mullite. The calcination temperature may be 300-1000°C, 400-900°C, or 500-800°C. Calcined inorganic minerals may be obtained by calcining inorganic minerals containing allophane, such as the Kanuma soil, Kuroboku soil, Satsuma soil, and Secard P1 mentioned above. This makes it possible to obtain calcined inorganic minerals containing calcined allophane (calcined allophane). Similarly, calcined inorganic minerals containing calcined halloysite (calcined halloysite) may be obtained. From the viewpoint of reactivity with cement clinker, calcined inorganic minerals preferably contain at least one of calcined allophane and calcined halloysite, and more preferably contain calcined allophane.

[0020] Based on the total amount of inorganic minerals and calcined inorganic minerals, the calcined inorganic mineral content may be 30% by mass or more, or 45% by mass or more, from the viewpoint of further increasing strength development, and may be 100% by mass or less, or 95% by mass or less, from the viewpoint of reducing the amount of CO2 generated when obtaining calcined inorganic minerals.

[0021] The calcined allophane or calcined halloysite content in the calcined product may be 30% by mass or more, or 45% by mass or more, from the viewpoint of further enhancing strength development, and may be 100% by mass or less, or 95% by mass or less, from the viewpoint of reducing the effort required to increase the purity of allophane or halloysite and from the viewpoint of availability.

[0022] The fact that inorganic minerals are calcined inorganic minerals is, 27 This can be confirmed by analysis using Al-NMR. Specifically, in calcined inorganic minerals, 27 When the sum of the peak areas of 4-coordinate Al, 5-coordinate Al, and 6-coordinate Al analyzed by Al-NMR is taken as 100%, the proportion of the peak area of ​​at least one of 4-coordinate Al and 5-coordinate Al is between 30% and 50%.

[0023] In calcined inorganic minerals, 4-coordinate Al and 5-coordinate Al have unstable skeletons and are thought to contribute to increased reactivity with cement clinker. The effect of this action can be fully enjoyed when the proportion of the peak area of ​​at least one of 4-coordinate Al and 5-coordinate Al is 30% or more. On the other hand, if the proportion of 4-coordinate Al and 5-coordinate Al is too high, the reaction with cement clinker may proceed rapidly. This phenomenon can be easily suppressed when the proportion of the peak area of ​​at least one of 4-coordinate Al and 5-coordinate Al is 50% or less. From these viewpoints, the proportion of the peak area of ​​at least one of 4-coordinate Al and 5-coordinate Al is preferably 30-45%, and more preferably 35-45%. From the viewpoint of easily obtaining the above effects, the proportion of the peak area of ​​both 4-coordinate Al and 5-coordinate Al may be 30-50%, preferably 30-45%, and more preferably 35-45%.

[0024] The sum of the peak areas of 4-coordinate Al and 5-coordinate Al is preferably 50% or more from the viewpoint of reactivity with cement clinker, and preferably 90% or less from the viewpoint of reaction rate with cement clinker. From these viewpoints, the sum of the peak areas of 4-coordinate Al and 5-coordinate Al is more preferably 60-90%, and even more preferably 70-80%. Therefore, the peak area of ​​6-coordinate Al is preferably 10-50%, more preferably 10-40%, and even more preferably 20-30%.

[0025] In order for an inorganic mineral to have the desired peak areas of 4-coordinate Al, 5-coordinate Al, and 6-coordinate Al, it is sufficient to calcine the inorganic mineral at a predetermined temperature, or more specifically, to calcine it in the manner described in the calcination process below.

[0026] The percentage of the above peak area is measured as follows: Calculated inorganic mineral radionuclides 27The chemical shift and coordination state of Al-NMR were analyzed using an NMR spectrometer JNM-ECZ800R (manufactured by JEOL Ltd.). The analytical method was the MAS (Magic Angle Spinning) method, using a 3.2 mm sample tube. The analytical conditions were: magnetic field strength: 18.79 T, frequency: 20 kHz, number of integrations: 256, pulse width: 90° (0.6 μs). 27 For the Al-NMR spectrum, the Voigt function, which is a convolution function of Gaussian and Lorentz functions, is used to separate the waveforms of each peak. Then, the integral value of each separated peak is used to calculate the area of ​​each peak. Note that for calcined inorganic minerals... 27 In the Al-NMR spectrum, peak P1 is observed in the chemical shift range of -10 ppm to 15 ppm, peak P2 in the range of 50 ppm to 80 ppm, and peak P3 in the range of 30 ppm to 40 ppm. Peak P1 corresponds to 6-coordinate Al, which originates from the inorganic mineral skeleton. Peaks P2 and P3 are thought to be generated by the partial breakdown of the inorganic mineral skeleton (e.g., decomposition and dehydroxylation of the 6-coordinate Al structure due to heat treatment at high temperatures), and originate from 4-coordinate Al and 5-coordinate Al, respectively. From the obtained peak areas of P1 to P3, the sum of the areas of P1 + P2 + P3, and the ratios of the areas of P2 and P3 relative to this sum are calculated.

[0027] The content of inorganic minerals and / or their calcined products in the hydraulic composition is 10% by mass or more and 70% by mass or less, based on the total amount of inorganic minerals and / or their calcined products, cement clinker, and gypsum. This allows for sufficient strength development while contributing to CO2 reduction. From the viewpoint of contributing to CO2 reduction, the content of inorganic minerals and / or their calcined products is preferably 15% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, even more preferably 30% by mass or more, and particularly preferably 35% by mass or more. Furthermore, from the viewpoint of further improving fluidity and the compressive strength of the hardened body, the content of inorganic minerals and / or their calcined products is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less.

[0028] The mass ratio of SiO2 to Al2O3 (SiO2 / Al2O3) of the inorganic mineral and / or its ceramic is 0.5 to 3.0, and the BET specific surface area of ​​the inorganic mineral and / or its ceramic is 30 to 180 m². 2 It may be / g. When the above mass ratio SiO2 / Al2O3 is within the above range, the reactivity between inorganic minerals and / or their calcined products and cement clinker is easily improved. From this viewpoint, the mass ratio SiO2 / Al2O3 is preferably 0.6 or higher, and more preferably 0.7 or higher. Furthermore, the mass ratio SiO2 / Al2O3 is preferably 2.5 or lower, and more preferably 2.3 or lower.

[0029] The SiO2 content in inorganic minerals and / or their calcined products is preferably 30% by mass or more, and preferably 55% by mass or less, from the viewpoint of reactivity with cement clinker. The Al2O3 content in inorganic minerals and / or their calcined products is preferably 20% by mass or more, and preferably 60% by mass or less, from the viewpoint of reactivity with cement clinker.

[0030] (Cement clinker) Examples of cement clinkers include Portland cement clinker and alumina cement clinker.

[0031] Portland cement clinker can be any Portland cement clinker used to prepare various types of Portland cement as specified in JIS R 5210:2003 "Portland Cement". Examples of the above-mentioned Portland cements include ordinary Portland cement, rapid-hardening Portland cement, moderate-heat Portland cement, and low-heat Portland cement. The Portland cement clinker may be any Portland cement clinker used to prepare ordinary Portland cement and rapid-hardening Portland cement.

[0032] The mineral composition of Portland cement clinker can be calculated by the Bogue equation. Here, the Bogue equation is an equation widely used as a formula for calculating the content ratio of main minerals in Portland cement clinker from the content ratio of chemical composition. By using the Bogue equation shown below, the contents of tricalcium silicate (3CaO·SiO₂, denoted as C₃S), dicalcium silicate (2CaO·SiO₂, denoted as C₂S), and tricalcium aluminate (3CaO·Al₂O₃, denoted as C₃A) in Portland cement clinker can be calculated. In addition, "%" in the following equations means "mass%". The chemical formula represents the content ratio (mass%) of each compound indicated by the chemical analysis value according to JIS R 5204:2019 "Method for X-ray fluorescence analysis of cement".

[0033] <Bogue equation> C3S[%]=(4.07×CaO[%])-(7.60×SiO2[%])-(6.72×Al2O3[%])-(1.43×Fe2O3[%])-(2.85×SO3[%]) C2S[%]=(2.87×SiO2[%])-(0.754×C3S[%]) C3A[%]=(2.65×Al2O3[%])-(1.69×Fe2O3[%]) C4AF[%]=3.04×Fe2O3[%]

[0034] (Gypsum) As the gypsum, for example, dihydrate gypsum, hemihydrate gypsum, and anhydrite can be used. One type of gypsum may be used alone, or a plurality of types may be used in combination.

[0035] Based on the total amount of inorganic minerals and / or their calcined products, cement clinker, and gypsum, a cement clinker and gypsum content of 30% by mass or more allows for sufficient strength development, while a content of 90% by mass or less helps to reduce CO2 emissions. From these viewpoints, although the content is 30% by mass or more, it is preferably 35% by mass or more, more preferably 40% by mass or more, and even more preferably 55% by mass or more. Furthermore, although the content is 90% by mass or less, it is preferably 80% by mass or less, and more preferably 65% ​​by mass or less.

[0036] The SO3 equivalent content of gypsum in the hydraulic composition may be 1.6% by mass or more, 1.7% by mass or more, 1.8% by mass or more, 2.0% by mass or more, 2.5% by mass or more, or 3.0% by mass or more, based on the total mass of the hydraulic composition, from the viewpoint of further reducing self-shrinkage, and may be 10% by mass or less, 7.5% by mass or less, 5.0% by mass or less, or 4.0% by mass or less, from the viewpoint of superior strength development.

[0037] From the viewpoint of strength development, the total amount (content) of inorganic minerals and / or their calcined products, cement clinker, and gypsum in the hydraulic composition is preferably 75% by mass or more, preferably 80% by mass or more, and more preferably 85% by mass or more, based on the total amount of the hydraulic composition.

[0038] (Carbonate) The hydraulic composition may contain carbonates. Carbonates can promote the hydration reaction between cement clinker and inorganic minerals and / or their calcined products. Examples of carbonates include alkaline earth metal carbonates added to the hydraulic composition for the purpose of promoting the hydration reaction between cement clinker and inorganic minerals and / or their calcined products, such as calcium carbonate (limestone) and magnesium carbonate. Alternatively, alkali metal carbonates such as sodium carbonate decahydrate (Na2CO3·10H2O), sodium carbonate (Na2CO3), potassium carbonate (K2CO3), and sodium sesquicarbonate dihydrate (Na3H(CO3)2·NaHCO3·2H2O), which react with inorganic minerals and / or their calcined products, can also be used.

[0039] As limestone, for example, commercially available limestone powder and powders mainly composed of calcium carbonate, such as crushed limestone powder, can be used. Preferably, the limestone contains those that conform to the small amount of mixed components described in JIS R 5210:2009 "Portland cement".

[0040] As the carbonate, artificial carbonates with fixed CO2 may be used. Examples of artificial carbonates include artificial calcium carbonate and artificial magnesium carbonate.

[0041] The carbonate content may be 2% by mass or more, 5% by mass or more, or 10% by mass or more, based on the total amount of cement clinker, gypsum, and carbonate, from the viewpoint of fluidity, and 60% by mass or less, 45% by mass or less, or 30% by mass or less, from the viewpoint of superior strength development. From the above viewpoint, the carbonate content may be 2 to 60% by mass, 5 to 45% by mass, or 10 to 30% by mass, based on the total amount of cement clinker, gypsum, and carbonate.

[0042] (Other ingredients) The hydraulic composition may contain, in addition to inorganic minerals and / or their calcined products, cement clinker, gypsum, and carbonates, other components such as inorganic fine powder, calcium hydroxide, powders containing calcium other than calcium hydroxide, concrete water-reducing agents, accelerators, and retarders (excluding inorganic minerals, cement clinker, gypsum, and carbonates). If the hydraulic composition contains other components, the content of these other components may be 25% by mass or less, 20% by mass or less, or 15% by mass or less, based on the total amount of the hydraulic composition.

[0043] Inorganic fine powder is added to the hydraulic composition to improve its strength development. Examples of inorganic fine powder include powdered materials such as silica and crushed stone. From the viewpoint of fluidity, the inorganic fine powder content in the hydraulic composition is preferably 0% by mass or more, and more than 0% by mass, based on the total amount of the hydraulic composition, while from the viewpoint of strength development, it is preferably 15% by mass or less.

[0044] <Cured body> The hardened body is obtained by hardening a paste containing the above-mentioned hydraulic composition and water. The hardening conditions are not particularly limited. The hardened body can be prepared in accordance with the method described in JIS R 5201:2015 "Physical Testing Methods for Cement".

[0045] From the viewpoint of fluidity, the amount of water in the paste is preferably 35 parts by mass or more per 100 parts by mass of the total amount of the hydraulic composition, while from the viewpoint of easily creating a dense void structure in the hardened body, it is preferably 80 parts by mass or less. From these viewpoints, the amount of water is preferably 35 to 80 parts by mass, and more preferably 50 to 70 parts by mass.

[0046] <Method for producing a hydraulic composition> A method for producing a hydraulic composition comprises a preparation step of mixing an inorganic mineral and / or its calcined product containing at least one of allophane and halloysite with gypsum and cement clinker or cement, and preparing a hydraulic composition in which, based on the total amount of the inorganic mineral and / or its calcined product, gypsum, and cement clinker or cement, the composition contains 10 to 70% by mass of the inorganic mineral and / or its calcined product, and 30 to 90% by mass of the cement clinker or cement and gypsum, and the SO3 content of the gypsum is 1.5% by mass or more based on the total mass of the hydraulic composition.

[0047] A method for producing a hydraulic composition may further include a calcination step in which an inorganic mineral is calcined at 500 to 950°C to obtain a calcined product before the preparation step, and the hydraulic composition may be prepared using the calcined product in the preparation step. That is, the hydraulic composition prepared in the preparation step may contain the calcined product obtained in the calcination step. In this case, the inorganic mineral contains at least one of allophane and halloysite.

[0048] (Preparation process) In the preparation process, inorganic minerals and / or their calcined products are mixed with cement clinker or cement and gypsum. Carbonates and other components mentioned above may also be mixed in with these components. The proportions of each raw material are as described above.

[0049] In the preparation process, both cement clinker and cement may be mixed. When both cement clinker and cement are mixed, the hydraulic composition prepared in the preparation process shall contain 10 to 70% by mass of inorganic minerals and 30 to 90% by mass of cement clinker, cement, and gypsum, based on the total amount of inorganic minerals and / or their calcined products, gypsum, cement clinker, and cement, and the SO3 content of gypsum shall be 1.5% by mass or more, based on the total mass of the hydraulic composition.

[0050] In the preparation step, each raw material may be pulverized. When pulverization is performed, the order of mixing and pulverization is not particularly limited. That is, pulverization may be performed after mixing all raw materials, mixing may be performed after individually pulverizing each raw material, or mixing and pulverization of each raw material may be performed simultaneously. Mixing may be carried out using a mixer such as a pan-type mixer, a tilting-drum mixer, or a ribbon mixer, for example, may be carried out by mixing and pulverizing using a pulverizer such as a ball mill, a vertical roller mill, or a roller press, or may be carried out by pulverizing each raw material and then mixing them with a mixer such as a mechanical mixer.

[0051] In the preparation step, an inorganic mineral containing at least one of allophane and halloysite may be mixed as the inorganic mineral, a calcined product containing at least one of calcined allophane and calcined halloysite may be mixed, or both of these inorganic minerals and calcined products may be mixed.

[0052] (Calcination Step) The calcination temperature in the calcination step is preferably 500°C or higher from the viewpoint of increasing the compressive strength of the inorganic mineral, and on the other hand, it is preferably 950°C or lower from the viewpoint of suppressing the formation of other minerals (for example, the formation of mullite in the case of allophane). From these viewpoints, the calcination temperature is more preferably 600 to 900°C. The calcination time is not particularly limited, but may be 0.5 to 5 hours, or 1 to 4 hours from the viewpoint of the influence on the crystal structure.

[0053] The calcination step is 27 a step of calcining the inorganic mineral such that the ratio of the peak area of at least one of 4-coordinated Al and 5-coordinated Al is 30 to 50%, when the sum of the peak areas of 4-coordinated Al, 5-coordinated Al and 6-coordinated Al analyzed by Al-NMR is taken as 100%. If the area of the peak P1 of 6-coordinated Al derived from the skeleton of the inorganic mineral is too large, sufficient compressive strength cannot be obtained. The calcination step can be said to be a step of causing partial collapse of the skeleton of the inorganic mineral, and generating peaks P2 and P3 derived from 4-coordinated Al and 5-coordinated Al that contribute to the improvement of compressive strength.

[0054] The above-described embodiment includes the following: [1] A hydraulic composition comprising an inorganic mineral and / or its calcined product containing at least one of allophane and halloysite, cement clinker, and gypsum, Based on the total amount of the inorganic minerals and / or the ceramics, the cement clinker and the gypsum, The inorganic mineral and / or the calcined material content is 10 to 70% by mass, and the total content of the cement clinker and the gypsum is 30 to 90% by mass. A hydraulic composition wherein the SO3 content of the gypsum is 1.5% by mass or more, based on the total mass of the hydraulic composition. [2] It also contains carbonates, The hydraulic composition according to [1], wherein the carbonate content is 2 to 60% by mass, based on the total amount of cement clinker, gypsum, and carbonate. [3] The mass ratio of SiO2 to the mass of Al2O3 in the inorganic mineral and / or the ceramic (SiO2 / Al2O3) is 0.5 to 3.0, and the BET specific surface area of ​​the inorganic mineral and / or the ceramic is 30 to 180 m². 2 A hydraulic composition according to [1] or [2], wherein the composition is / g. [4] A hydraulic composition according to any one of [1] to [3], comprising the above or a ceramic. [5] The hydraulic composition according to [4], wherein the calcined allophane content in the calcined product is 30% by mass or more. [6] A cured body obtained by curing a paste containing a hydraulic composition and water as described in any of [1] to [5]. [7] The preparation step includes mixing an inorganic mineral and / or its calcined product containing at least one of allophane and halloysite, gypsum, and cement clinker or cement to prepare a hydraulic composition. The hydraulic composition, A method for producing a hydraulic composition, wherein, based on the total amount of the inorganic minerals and / or the calcined material, the content of the inorganic minerals and / or the calcined material is 10 to 70% by mass, and the total content of the cement clinker or the cement and the gypsum is 30 to 90% by mass, and based on the total mass of the hydraulic composition, the content of the gypsum in terms of SO3 is 1.5% by mass or more. [8] The manufacturing method according to [7], further comprising a calcination step of calcining the inorganic mineral at 500 to 950°C before the preparation step to obtain the calcined product, wherein the hydraulic composition contains the calcined product. [Examples]

[0055] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited to these examples.

[0056] <Raw materials for hydraulic compositions> The following ingredients were prepared. • Secard P1 (Inorganic mineral containing allophane; allophane content after drying at 105°C: 72.5% by mass; manufactured by Shinagawa General Co., Ltd.) • Ordinary Portland cement (OPC, Blaine specific surface area 3140 cm²) 2 / g, Cement clinker content: 92.2% by mass, Gypsum content: 3.2% by mass, Hemihydrate gypsum content in gypsum: 63% by mass, SO3 equivalent content of gypsum: 1.68% by mass, Limestone content: 4.6% by mass, Manufactured by UBE Mitsubishi Cement Corporation) • Dihydrate gypsum (manufactured by Fujifilm Wako Corporation, reagent grade calcium sulfate dihydrate)

[0057] The proportion of hemihydrate gypsum in the gypsum contained in ordinary Portland cement was calculated using the following formula. The hemihydrate gypsum content and dihydrate gypsum content were determined by differential thermal and thermogravimetric analysis (TG-DTA). Gypsum hemihydrate ratio (mass %) = gypsum hemihydrate content (mass %) / (gypsum hemihydrate content (mass %) + gypsum dihydrate content (mass %)) × 100

[0058] The chemical composition of Secard P1 was measured by the fundamental parameter method, and the chemical composition of OPC was measured according to the method of JIS R 5204. Furthermore, the ignition loss of Secard P1 and OPC was measured according to the method of JIS R 5202:2010. Note that the value for Secard P1 was measured using a sample dried at 105°C. The results are shown in Table 1. [Table 1]

[0059] The prepared Secard P1 was calcined at 900°C for 1 hour to obtain calcined inorganic minerals. For the obtained calcined material, the ignition loss (21.0% by mass) when Secard P1 was calcined at 900°C for 1 hour was used to calculate the allophane content (by mass) of the calcined material, assuming that all the allophane in Secard P1 was converted to calcined allophane. Furthermore, the amount of nitrogen gas adsorbed on the obtained calcined material was measured using a BELSORPMINI manufactured by Microtrac-Bel, and the BET specific surface area (m²) was calculated from the measured nitrogen gas adsorption amount. 2 The value per g was calculated. The results are shown in Table 2. [Table 2]

[0060] <Preparation of hydraulic composition> (Examples 1 and 2, Comparative Examples 1 and 2, and Reference Example 1) Hydraulic compositions for Examples 1 and 2, Comparative Examples 1 and 2, and Reference Example 1 were prepared by mixing calcined inorganic minerals, OPC, limestone, and dihydrate gypsum. The proportions (parts by mass) of each raw material used are shown in Table 3. Note that the proportions of limestone and dihydrate gypsum shown in Table 3 are those added separately and do not include the limestone and dihydrate gypsum contained in the OPC. [Table 3]

[0061] The content (mass%) of each component in the hydraulic compositions obtained in Examples 1 and 2, Comparative Examples 1 and 2, and Reference Example 1 is shown in Table 4. Note that the content of cement clinker, calcined metal, limestone, and gypsum, as well as the gypsum content (SO3 equivalent) in Table 4, are based on the total amount of the hydraulic composition. [Table 4]

[0062] [Autologous contraction test] Each of the obtained hydraulic compositions was mixed with water in a mass ratio of 100:45 (hydraulic composition:water), and a paste was prepared by mixing using a Three One Motor (manufactured by HEIDEN) at a rotation speed of 300 rpm and a mixing time of 1 minute 30 seconds. Since bleeding occurred in the obtained paste, the paste was kneaded repeatedly at 30-minute intervals until the bleeding subsided.

[0063] Next, holes were drilled at 35mm and 65mm from the top of the mold (a paper sonomold measuring φ50mm x 100mm), and the instrument body of the embedded strain gauge KM-30 (manufactured by Tokyo Sokki Kenkyusho, a strain gauge type strain gauge) was fixed in two places with string so as to be perpendicular to the sensing direction of the instrument. In addition, a thin layer of lubricant was applied to the inner wall surface of the mold to minimize internal restraint force as much as possible.

[0064] Next, the obtained paste was cast into the mold in three stages using a vibration table. Then, to prevent moisture evaporation, the top of the mold was immediately covered with Parafilm after the paste was cast, and further sealed with an aluminum sheet. The mold was then stored in a constant temperature bath at 20°C, and the actual strain was measured using a strain gauge 250 hours and 1000 hours after the start of setting. Assuming that the inside of the container was stress-free, the amount of autologous shrinkage (autologous shrinkage strain) (unit: με) at 250 hours and 1000 hours after the start of setting was calculated from the measured actual strain using Equation 1. The coefficient of linear expansion was calculated from the strain measured when the temperature of the test specimen was changed after the completion of autologous shrinkage. The results are shown in Table 5.

number

[0065] [Compression strength test] For each hydraulic composition obtained, the compressive strength (N / mm²) was tested in accordance with the description in JIS R 5201:2015 "Physical Testing Methods for Cement". 2 ) was measured.

[0066] Specifically, a mortar composition for evaluation was prepared by mixing 50 parts by mass of water with 100 parts by mass of each obtained hydraulic composition. The above-mentioned mixture was adjusted so that the ratio of hydraulic composition to water was 100:50 (by mass, in accordance with the description in JIS R 5201:2015 "Physical Test Methods for Cement").

[0067] Mortar hardened bodies were prepared using each of the obtained mortar compositions. First, the above mortar compositions were mixed as mortar in a constant temperature chamber at 20°C and filled into a 4cm × 4cm × 16cm mold (prepared in accordance with the description in JIS R 5201:2015 "Physical Test Methods for Cement"). The mold was stored in a humidity chamber and cured for 24 hours under conditions of 20°C and 60%RH. After 24 hours of curing, the mold was removed to obtain a hardened mortar body. The obtained hardened mortar bodies were cured in water in a constant temperature chamber at 20°C for 7 days (age 7 days) and 28 days (age 28 days). The hardened mortar bodies after water curing were used as test specimens, and the compressive strength of the hardened mortar bodies at 7 days (7d) and 28 days (28d) was measured.

[0068] The compressive strength was measured in accordance with JIS R 5201:1992 "Physical Testing Methods for Cement". The compressive strength ratio (%) was calculated from the measured compressive strength. The results are shown in Table 5. Note that the compressive strength ratio in Table 5 is a relative value when the compressive strength of the hardened body of the mortar composition prepared from the hydraulic composition of Reference Example 1 is set to 100.

[0069] [Table 5]

Claims

1. A hydraulic composition comprising an inorganic mineral and / or its calcined product containing at least one of allophane and halloysite, cement clinker, and gypsum, Based on the total amount of the inorganic minerals and / or the ceramics, the cement clinker and the gypsum, The inorganic mineral and / or the calcined material content is 10 to 70% by mass, and the total content of the cement clinker and the gypsum is 30 to 90% by mass. Based on the total mass of the hydraulic composition, the SO of the gypsum ３ A hydraulic composition having a converted content of 1.5% by mass or more.

2. It also contains carbonates, The hydraulic composition according to claim 1, wherein the carbonate content is 2 to 60% by mass, based on the total amount of cement clinker, gypsum, and carbonate.

3. The Al of the inorganic mineral and / or the calcined material ２ O ３ SiO for the mass of ２ The mass ratio (SiO ２ / Al ２ O ３ The ratio is 0.5 to 3.0, and the BET specific surface area of ​​the inorganic mineral and / or the ceramic is 30 to 180 m². ２ The hydraulic composition according to claim 1, wherein the concentration is / g.

4. The hydraulic composition according to claim 1, comprising the aforementioned ceramic material.

5. The hydraulic composition according to claim 4, wherein the calcined allophane content in the calcined product is 30% by mass or more.

6. A cured body obtained by curing a paste containing the hydraulic composition and water according to any one of claims 1 to 5.

7. The preparation step includes mixing an inorganic mineral and / or its calcined product containing at least one of allophane and halloysite, gypsum, and cement clinker or cement to prepare a hydraulic composition. The hydraulic composition, Based on the total amount of the inorganic mineral and / or the calcined product, the gypsum, and the cement clinker or the cement, the content of the inorganic mineral and / or the calcined product is 10 to 70 mass%, and the total content of the cement clinker or the cement and the gypsum is 30 to 90 mass%, and based on the total mass of the hydraulic composition, the SO of the gypsum ３ converted content is 1.5 mass% or more, a method for producing a hydraulic composition.

8. The manufacturing method according to claim 7, further comprising a calcination step of calcining an inorganic mineral at 500 to 950°C before the preparation step to obtain the calcined product, wherein the hydraulic composition includes the calcined product.

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