Method for producing hydraulic molded body

Abstract

To provide a method for producing a hydraulic molded body, capable of obtaining excellent strength even when a bone powder content is increased.SOLUTION: A hydraulic composition containing Portland cement and bone powder, wherein a content of the bone powder excluding water is 30 to 60 wt.%, is placed into a mold, cured, and demolded to take out a hydraulic molded body. The content of the bone powder is 40 to 150 pts.mass. with respect to 100 pts.mass. of Portland cement. Accordingly, a bone Buddha statue having a high bone powder content and excellent strength can be obtained.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a hydraulically hardened body using cement. [Background technology]

[0002] Traditionally, after cremation, bone powder has been used to create Buddhist statues, gravestones, memorial tablets, lanterns, animal figures, and other sculptures, which are then enshrined (see, for example, Patent Document 1). For example, a bone Buddha made from the remains can attract the faith of many people because it combines the worship of Buddha with the idea of ​​ancestral worship. Furthermore, by containing the remains, a bone Buddha can also provide comfort to the bereaved family and those associated with the deceased.

[0003] However, conventional sculptures containing bone powder tend to contain a low amount of bone powder in order to maintain strength, and it is desirable to incorporate as much bone powder as possible. Furthermore, given social circumstances such as a declining birthrate and aging population, a high death rate, and an increase in abandoned graves, it is considered to collect bones that have been around for a certain period of time or bones of unrelated people and turn them into bone Buddha statues that can be worshiped by many people. On the other hand, because bone Buddha statues are often installed inside buildings such as temples and shrines, it is desirable to incorporate as much bone powder as possible into a bone Buddha statue of a limited size while maintaining strength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-300896 Summary of the Invention [Problem to be solved by the invention]

[0005] The present technology has been proposed in view of the above-mentioned conventional situation, and provides a method for producing a hydraulically hardened molded body that can obtain excellent strength even when the bone powder content is high. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have found that the above object can be achieved by the following method for producing a hydraulically hardened formed body, and have completed the present technology.

[0007] [1] A method for producing a hydraulically set body, comprising: casting a hydraulic composition containing Portland cement and bone powder, with the bone powder content excluding water being 30 to 60 wt %, into a formwork, allowing it to harden, and then removing the formwork to extract the hydraulically set body. [2] The method for producing a hydraulically set molded body according to [1], wherein the content of the bone powder is 40 to 150 parts by mass per 100 parts by mass of the Portland cement. [3] The method for producing a hydraulically set molded body according to [2], wherein the water-cement mass ratio of the hydraulic composition is 0.30 to 0.50. [4] The method for producing a hydraulically hardened molded body according to any one of [1] to [3], wherein the Portland cement is white Portland cement. [5] The method for producing a hydraulically set molded body according to any one of [1] to [3], wherein the hydraulic composition is a mortar composition. [6] The method for producing a hydraulically hardened molded body according to any one of [1] to [3], wherein the size of the bone powder is 2 mm or less. [7] The method for manufacturing a hydraulically hardened molded body according to any one of [1] to [3], wherein the formwork is composed of multiple parts arranged in vertical steps from the bottom to the top, and the multiple parts are detachable. [8] The method for producing a hydraulically hardened molded body according to [7], wherein the parts are removed stepwise from the bottom to the top of the formwork to extract the hydraulically hardened molded body. [9] The method for producing a hydraulically hardened molded body according to any one of [1] to [3], wherein the hydraulically hardened molded body is a part or the whole of a Buddhist statue.

[10] A hydraulically set molded body produced by the method according to any one of [1] to [9] above. [Effects of the Invention]

[0008] According to this technology, excellent strength can be obtained by using a hydraulic composition containing Portland cement and a predetermined amount of bone powder. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a flowchart showing a method for manufacturing a hydraulically set molded body to which the present technology is applied. [Figure 2] FIG. 2 is a front view showing a schematic diagram of a bone Buddha. [Figure 3] FIG. 3 is a front view showing a schematic view of the principal image portion of the bone Buddha. [Figure 4] FIG. 4 is a front view showing a schematic view of the upper lotus part of the bone Buddha. [Figure 5] FIG. 5 is a front view showing a schematic view of the lower lotus part of the bone Buddha. [Figure 6] FIG. 6 is a front view showing a schematic view of the halo of the bone Buddha. [Figure 7] Figure 7 is a photograph showing a bone Buddha statue made using this technology. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail in the following order with reference to the drawings. 1. Manufacturing method of hydraulic molding 2. Working Example

[0011] <1. Manufacturing method of hydraulic molding> Fig. 1 is a flowchart showing a method for manufacturing a hydraulic molded body to which the present technology is applied. As shown in Fig. 1, the method for manufacturing a hydraulic molded body includes a preparation step (A) of preparing a hydraulic composition, a casting step (B) of casting the hydraulic composition into a formwork, a hardening step (C) of hardening the hydraulic composition, a demolding step (D) of demolding the hydraulic molded body from the formwork, and a finishing step (E) of assembling, coloring, etc. the hydraulic molded body.

[0012] The hydraulic molding may be, for example, all or part of a shaped object such as a Buddhist statue, a gravestone, a memorial tablet, a lantern, an animal, etc. The bone powder is preferably pulverized burnt bones, and is preferably treated by sterilization, drying, heating, etc.

[0013] Below, we will take up the method of manufacturing a bone Buddha statue as a specific example of a method of manufacturing a hydraulically hardened molded body, and explain in detail the preparation process (A), the casting process (B), the hardening process (C), the demolding process (D), and the finishing process (E).

[0014] Fig. 2 is a front view showing a typical bone Buddha, and Figs. 3 to 6 are front views showing the principal image, upper lotus, lower lotus, and halo of the bone Buddha, respectively. As shown in Figs. 2 to 6, the specific method for manufacturing a bone Buddha involves dividing the bone Buddha into four sections: principal image 11, upper lotus 12, lower lotus 13, and halo 14, each of which is shaped separately, and then assembling these sections to create the bone Buddha.

[0015] [Preparation process (A)] In the preparation step (A), a hydraulic composition containing Portland cement and bone powder is prepared. The hydraulic composition may be a mortar composition containing fine aggregate or a concrete composition containing coarse aggregate. Here, fine aggregate refers to aggregate that passes through a 10 mm sieve and in which 85% or more of the total aggregate by mass is less than 5 mm in size. Coarse aggregate refers to aggregate that passes through a 5 mm sieve and in which 85% or more of the total aggregate by mass is 5 mm or larger in size. From the perspective of producing a Buddhist statue of ashes, the hydraulic composition is preferably a mortar composition containing bone powder as fine aggregate. This allows for a smoother surface than a concrete composition containing coarse aggregate.

[0016] Portland cement can be any of the Portland cements specified in JIS R 5210 (normal, early strength, extra early strength, moderate heat, low heat, sulfate resistant), and white Portland cement with a reduced ferric oxide content. From the perspective of producing a Buddhist statue of ashes, white Portland cement is preferred. This allows the color of the bone powder to show through and makes coloring easier.

[0017] The bone powder can be crushed bones of humans or animals. The bone powder used for the bone buddha statue can be crushed burned bones. The main component of burned bones is calcium phosphate, and mortar compositions containing burned bone powder as fine aggregate can achieve strength equal to or greater than that of cement paste.

[0018] The size of the bone powder is preferably 2 mm or less. Here, "2 mm or less" means that the bone powder passes through a 5 mm sieve and 85% or more of the total mass is 2 mm or less. The small size of the bone powder improves the strength of the hydraulic molding and also makes the surface of the hydraulic molding smooth.

[0019] The content of bone powder in the hydraulic composition excluding water is preferably 30 wt% or more, more preferably 35 wt% or more, and even more preferably 40 wt% or more. The content of bone powder in the hydraulic composition excluding water is preferably 60 wt% or less, more preferably 55 wt% or less, and even more preferably 50 wt% or less. This allows the hydraulic molding to have excellent strength even when the bone powder content is high.

[0020] The content of bone powder is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 60 parts by mass or more, and even more preferably 60 parts by mass or more, relative to 100 parts by mass of Portland cement. The content of bone powder is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, even more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less, relative to 100 parts by mass of Portland cement.

[0021] The water-cement mass ratio of the hydraulic composition is preferably 0.30 or more, more preferably 0.32 or more, and even more preferably 0.35 or more. The water-cement mass ratio of the hydraulic composition is preferably 0.60 or less, more preferably 0.50 or less, and even more preferably 0.45 or less. This allows the hydraulic molding to have excellent strength even when the bone powder content is increased.

[0022] [Pouring process (B)] In the casting process (B), the hydraulic composition is cast into a mold of the master model of the shaped object. The master model mold is not particularly limited, but it is preferable to create it by scanning the master model using a 3D printer. This makes it possible to create molds of complex shapes without having to consider adhesion between the master model and the mold, compared to creating a mold by applying FRP (Fiber Reinforced Plastics) or the like to the master model.

[0023] For example, the amount of hydraulic composition poured into the master formwork is preferably in the range of 50 kg to 200 kg. For example, in the case of producing a Buddhist bone statue, it is preferable to prepare a formwork by dividing the master model of the Buddhist bone statue into four parts, namely, the principal image part 11, the upper lotus part 12, the lower lotus part 13, and the halo part 14, within the above-mentioned pouring amount range, as shown in Figures 2 to 6.

[0024] Furthermore, it is preferable that the master form is composed of multiple parts arranged in vertical steps from the bottom to the top, and that the multiple parts are detachable. For example, it is preferable that the parts of the master form are detachable at intervals of 50 mm to 200 mm in the vertical direction. This allows the casting process (B), reaction process (C), and demolding process (D) to be repeatedly performed in vertical steps from the bottom to the top of the form.

[0025] It is also preferable to apply a release agent to the inside of the parts into which the hydraulic composition will be poured and then allow it to dry in advance. This allows the hydraulic composition to be poured and hardened stepwise from the bottom to the top of the formwork, and also allows the mold parts to be removed stepwise from the bottom to the top of the formwork, which prevents cracks from occurring due to insufficient drainage, as will be described later.

[0026] [Curing process (C)] In the hardening step (C), the hydraulic composition poured into the formwork is hardened to form a hydraulic compact. The Portland cement in the hydraulic composition reacts with water (hydration reaction) to produce hard hydrates. The hydrates continue to be produced one after another, holding the bone powder together, until the hydration reaction is complete, increasing the strength of the concrete.

[0027] [Demolding process (D)] In the demolding step (D), the hydraulically set molded body is demolded from the formwork. Demolding is preferably carried out one to three days after casting. In addition, if the original formwork is composed of multiple parts arranged in stages in the vertical direction from the bottom to the top, and the multiple parts are removable, it is preferable to remove the parts in stages from the bottom to the top of the hardened area one to three days after casting, and then remove the hydraulically set molded body. This prevents cracks from occurring due to insufficient drainage.

[0028] The hydraulic molded body released from the mold is preferably allowed to air dry for at least 3 months, more preferably at least 4 months, and even more preferably at least 5 months. Here, air drying refers to drying in air at room temperature (5°C to 35°C). The hydraulic molded body released from the mold may be dried at room temperature of 15°C to 25°C or in a thermostatic chamber. When the hydraulic molded body released from the mold is dried in a thermostatic chamber, the temperature is preferably 10°C to 45°C, more preferably 20°C to 45°C, even more preferably 30°C to 45°C, and even more preferably 35°C to 45°C.

[0029] [Finishing process (E)] In the finishing process (E), the hydraulically hardened body is assembled and colored. In the finishing process (E), for example, the four parts of the principal image part 11, the upper lotus part 12, the lower lotus part 13, and the halo part 14 shown in Figures 3 to 6, respectively, are assembled and colored to create the bone Buddha shown in Figure 2. [Example]

[0030] <2. Example> Examples of the present technology will be described in detail below. In these examples, a hydraulic composition was prepared and a test specimen was made using the hydraulic composition. The compressive strength of the test specimen was then evaluated. A Buddhist statue of a Buddhist statue was also made using the hydraulic composition. However, the present technology is not limited to these examples.

[0031] [Test 1-Test 11] The hydraulic components, bone powder, and water were mixed in the proportions (parts by mass) shown in Table 1 to prepare hydraulic compositions. White cement: Pacific Cement Corporation, White cement Yoshino Gypsum Sales Co., Ltd., resin-filled hard plaster, Histone HLP White Gypsum: Keikagaku Kogyo Co., Ltd., high-grade machining plaster Bone meal: Crushed burnt bones to a maximum size of 2 mm or less

[0032] The water-soluble composition was poured into a specimen mold, allowed to dry naturally for 7 days, and then demolded to obtain a cylindrical specimen with a diameter of 66 mm and a height of 47 mm (cross-sectional area: 3420 mm). 2 Then, in accordance with JISA 1108, a compressive load was applied to the donor at a rate of 1 mm / min using a universal material testing machine (Shimadzu Corporation, AG20kND), the maximum test force was measured, and the compressive strength was calculated (Saitama Prefectural Industrial Technology Center: No. I22-1613).

[0033] Table 1 shows the measurement results of the maximum test force and the calculated results of the compressive strength in Tests 1 to 11.

[0034] [Table 1]

[0035] Test 2-4, which mixed white cement and bone powder, achieved compressive strength equal to or greater than that of Test 1, which used only white cement paste. In particular, Test 3-4 achieved compressive strength superior to that of Test 1.

[0036] Tests 5-7 contained resin gypsum, and Tests 6-7, which contained bone powder, showed a decrease in compressive strength compared to Test 5, which contained only resin gypsum paste. Tests 8-11 contained gypsum, and Tests 10-11, which contained bone powder, showed a decrease in compressive strength compared to Test 8, which contained only gypsum paste.

[0037] Tests 1-11 showed that by using white cement as a hydraulic binder, excellent strength can be obtained even with a high bone powder content. In particular, it was found that by using a bone powder content excluding water of 30-60 wt%, excellent strength equivalent to or greater than that of white cement paste can be obtained.

[0038] [Creating a bone Buddha statue] As shown in Test 3, a hydraulic composition was prepared by mixing 120 parts by mass of white cement, 80 parts by mass of bone powder, and 45 parts by mass of water. The bone powder used was the remains of 729 bodies interred in the "Tower of Gratitude," a permanent memorial tomb, over a ten-year period from April 2013 to March 2023.

[0039] The mold was divided into four parts: the principal image, upper lotus, lower lotus, and halo, using the Dainichi Nyorai stone Buddha as a model prototype. The mold was also constructed using a 3D printer, consisting of over 100 parts arranged in vertical stages from bottom to top, with each part being removable. The amount of hydraulic composition poured (including water) into the molds for the principal image, upper lotus, lower lotus, and halo was 96.5 kg, 183.7 kg, 172.8 kg, and 62.4 kg, respectively.

[0040] The hydraulic composition was poured in stages from the bottom to the top of the mold, and the parts were removed one by one from the hardened parts one to three days after pouring. The removed hydraulic molded bodies were then allowed to air dry for approximately five months. After air drying, the main image, upper lotus, lower lotus, and halo were assembled and painted to create the bone Buddha.

[0041] Figure 7 is a photograph of a bone Buddha statue made using this technology. As shown in Figure 7, a bone Buddha statue with excellent strength was made without any cracks. [Explanation of symbols]

[0042] 11 Gohonzon part, 12 Upper lotus part, 13 Lower lotus part, 14 Halo part

Claims

1. The method for producing a hydraulically set body comprises pouring a hydraulic composition containing Portland cement and bone powder, the content of the bone powder excluding water being 30 to 60 wt %, into a formwork, allowing it to harden, and removing the formwork to take out the hydraulically set body.

2. 2. The method for producing a hydraulically set molded body according to claim 1, wherein the content of the bone powder is 40 to 150 parts by mass per 100 parts by mass of the Portland cement.

3. 3. The method for producing a hydraulically formed body according to claim 2, wherein the water-cement mass ratio of the hydraulic composition is 0.30 to 0.

60.

4. 4. The method for producing a hydraulically set molded body according to claim 1, wherein the Portland cement is white Portland cement.

5. The method for producing a hydraulically set molded body according to any one of claims 1 to 3, wherein the hydraulic composition is a mortar composition.

6. 4. The method for producing a hydraulically hardened molded body according to claim 1, wherein the size of the bone powder is 2 mm or less.

7. The method for manufacturing a hydraulically formed body according to any one of claims 1 to 3, wherein the formwork is composed of a plurality of parts arranged in vertical steps from the bottom to the top, and the plurality of parts are detachable.

8. 8. The method for producing a hydraulically set molded body according to claim 7, wherein the parts are removed stepwise from the bottom to the top of the formwork to remove the hydraulically set molded body.

9. The method for producing a hydraulically hardened molded body according to any one of claims 1 to 3, wherein the hydraulically hardened molded body is a part or the whole of a Buddhist statue.

10. A hydraulically set molded body produced by the method according to any one of claims 1 to 9.

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