Method for manufacturing a molded body, method for reinforcing a molded body, and compression molded body

Abstract

To provide a method for producing a molded product, a method for reinforcing a molded product, and a compressed molded product that can easily improve the strength of a molded product.SOLUTION: A method for producing a molded body according to the present disclosure includes a molding step of forming a primary molded body by applying manufacturing pressure to a concrete material made from concrete waste as a raw material and compressing the same, and a post-processing step in which the primary molded body is heated while being exposed to moisture or heated after being exposed to moisture.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a method for manufacturing a molded article, a method for reinforcing a molded article, and a compression molded article. [Background technology]

[0002] To realize a sustainable society, the recycling of concrete waste is desired. Patent document 1 describes a technology for reusing concrete waste. However, obtaining recycled concrete with sufficient strength requires a complex processing process. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-025631 [Overview of the project] [Problems that the invention aims to solve]

[0004] Therefore, the present invention aims to provide a method for manufacturing a molded article, a method for reinforcing a molded article, and a compression molded article that can easily improve the strength of the molded article. [Means for solving the problem]

[0005] The present invention includes the following embodiments. [1] A method for manufacturing a molded body, comprising: a molding step of forming a primary molded body by applying manufacturing pressure to a concrete material made from concrete waste as a raw material and compressing it; and a post-treatment step of heating the primary molded body while exposing it to moisture or heating it after exposing it to moisture. [2] The method for manufacturing a molded article according to [1], wherein the concrete material comprises at least one of crushed concrete and crushed concrete. [3] The method for manufacturing a molded article according to [1] or [2], wherein the post-processing step includes a step of autoclaving the primary molded article. [4] The method for manufacturing a molded article according to [3], wherein the autoclave temperature of the autoclave treatment is 100°C to 300°C and the autoclave treatment time is 4 hours to 48 hours. [5] A method for manufacturing a molded article according to any one of [1] to [4], wherein the concrete material comprises one or more cement materials selected from the group consisting of Portland cement, blast furnace slag fine powder, silica fume, and fly ash; water; one or more fine aggregates selected from the group consisting of natural sand, blast furnace slag, and limestone sand; and one or more coarse aggregates selected from the group consisting of natural gravel, blast furnace slag coarse aggregate, limestone gravel, and road steel slag base course material. [6] A method for manufacturing a molded article according to any one of [1] to [5], wherein the porosity of the molded article increases before and after the post-processing step. [7] The method for manufacturing a molded article according to any one of [1] to [6], wherein the manufacturing pressure in the molding step is less than 50 MPa. [8] A method for manufacturing a molded article according to any one of [1] to [7], further comprising a settling step of allowing the primary molded article to stand for a predetermined time after the molding step and before the post-processing step. [9] The concrete material comprises particles with a particle size of more than 300 μm and 1.5 mm or less. A method for manufacturing a molded article according to any one of [1] to [8].

[10] A method for manufacturing a molded article according to any one of [1] to [9], wherein the compressive strength of the molded article increases before and after the post-processing step, and the rate of increase is 50% or more.

[11] A method for manufacturing a molded article according to any one of [1] to

[10] , wherein the compressive strength of the molded article after the post-processing step is 18 MPa or more.

[12] The method for manufacturing a molded article according to [1], wherein the post-processing step includes immersing the primary molded article in water and heating the primary molded article removed from the water.

[13] A method for reinforcing a molded body, comprising the step of increasing the compressive strength of a molded body formed by applying manufacturing pressure to a concrete material made from concrete waste as a raw material, by heating the molded body while exposing it to moisture or heating it after exposing it to moisture.

[14] A compressed concrete material made from concrete waste, wherein the compressive strength is 18 MPa or more, and the reduction rate of compressive strength when saturated with water is 30% or less.

[15] The compression molded article according to

[14] , wherein the void ratio is 22.6% or more. [Effects of the Invention]

[0006] According to embodiments of the present invention, it is possible to provide a method for manufacturing a molded article, a method for reinforcing a molded article, and a compression molded article that can easily improve the strength of the molded article. [Brief explanation of the drawing]

[0007] [Figure 1] A graph comparing the compressive strength of molded bodies that have not undergone autoclave treatment and molded bodies that have undergone autoclave treatment under various conditions. [Figure 2] A graph comparing the compressive strength of molded bodies manufactured from various materials. [Figure 3] A graph showing the porosity of molded articles that have not undergone autoclave treatment and those that have undergone autoclave treatment. [Figure 4] A graph comparing the compressive strength of molded articles before and after saturation treatment. [Figure 5] A graph showing the compressive strength of molded bodies under various manufacturing pressures. [Figure 6] A graph showing the compressive strength of a molded body in relation to the weight ratio of particle groups P1 and P2 with different particle sizes. [Figure 7] A graph comparing the compressive strength of molded bodies that have not undergone immersion heat treatment and molded bodies that have undergone immersion heat treatment under various conditions. [Modes for carrying out the invention]

[0008] Hereinafter, a method for manufacturing a molded body, a method for reinforcing a molded body, and a compression molded body according to embodiments will be described. Note that the following embodiments show one aspect of the present invention, do not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention.

[0009] In conventional research on manufacturing concrete materials using concrete waste, it has not been easy to improve the strength of the formed recycled concrete, and often requires laborious processes such as compression treatment at high pressure. Therefore, the present inventor repeated trials and errors under the problem awareness that it is necessary to easily improve the strength of the molded body, and found a new method for improving the strength of the molded body by combining the process of exposing the manufactured molded body to water and the process of heating. In addition, the present inventor has found that, according to this method, depending on the conditions, manufacturing conditions such as the manufacturing pressure when manufacturing the molded body can be relaxed, and a molded body having high strength can be manufactured more easily.

[0010] <Method for manufacturing a molded body> In one embodiment, there is provided a method for manufacturing a molded body, including a molding step of forming a primary molded body by applying a manufacturing pressure to a concrete material made from concrete waste and compressing it, and a post-treatment step of heating the primary molded body while exposing it to moisture or heating it after exposing it to moisture.

[0011] In this specification, “concrete material” means a tangible object containing concrete. For example, concrete material may be a concrete structure of any shape, or concrete in various forms such as fragments, granules, or powder obtained by crushing or pulverizing a concrete structure. In this specification, “concrete waste” means concrete material that falls under the category of waste. Examples of concrete waste include concrete rubble generated during the construction of structures such as buildings, roads, railways, and utility poles. In this specification, “concrete material made from concrete waste” means concrete material that contains at least partially materials derived from concrete waste. In this specification, “crushing” means breaking an object into pieces. In this specification, “pulverization” means breaking an object into pieces finer than “crushing” (for example, into powder). In this specification, “exposure to moisture” means bringing an object into contact with saturated water vapor or immersing at least a portion of an object in water. For example, bringing an object into contact with saturated water vapor in an autoclave or immersing an object in water is included in “exposure to moisture”.

[0012] In one embodiment, the concrete material includes at least one of crushed concrete waste and pulverized concrete powder. For example, the crushed concrete is a fragmentary or granular concrete material. By using concrete materials derived from concrete waste in this way, concrete can be reused, and recycled concrete that contributes to a sustainable circular society can be provided.

[0013] For example, the particle size of crushed concrete is greater than 300 μm and less than or equal to 1 cm, preferably less than or equal to 5 mm, less than or equal to 3 mm, less than or equal to 2 mm, less than or equal to 1.5 mm, less than or equal to 1.18 mm, or less than or equal to 1 mm. In this specification, "particle size" means the maximum diameter of the primary particles. For example, the particle size of concrete powder is less than or equal to 300 μm, preferably less than or equal to 200 μm, less than or equal to 150 μm, less than or equal to 105 μm, less than or equal to 100 μm, less than or equal to 65 μm, or less than or equal to 50 μm. Here, the boundary between crushed concrete and concrete powder is described as having a particle size of 300 μm, but the present invention is not limited thereto, and the above boundary may be a particle size of 100 μm, 200 μm, 400 μm, 500 μm, etc.

[0014] In one embodiment, the concrete material contains particles with a particle size greater than 300 μm and less than or equal to 1.5 mm. For example, it is preferable that the concrete material does not contain particles with a particle size of 300 μm or less, in that the process of finely crushing the material can be omitted.

[0015] In one embodiment, the concrete material comprises any known cement, any known coarse aggregate, any known fine aggregate, and water. For example, the concrete material comprises one or more cement selected from the group consisting of Portland cement, blast furnace slag powder, silica fume, and fly ash; water; one or more fine aggregates selected from the group consisting of natural sand, blast furnace slag, and limestone sand; and one or more coarse aggregates selected from the group consisting of natural gravel, blast furnace slag coarse aggregate, limestone gravel, and road steel slag base material. The concrete material may further contain an air-entraining agent. The proportions of each component in the concrete material can be arbitrarily determined. For example, the concrete material comprises 1 m of concrete. 3 Based on this, 200 kg / m 3 ~600kg / m 3 Cement material, 50 kg / m 3 ~300kg / m 3 Water, 0.1 kg / m 3 ~15kg / m 3 Air entraining agent, 400 kg / m 3 ~1100kg / m3 fine aggregate, and 500 kg / m 3 ~1200 kg / m 3 coarse aggregate. For example, the blending amount of aggregate (fine aggregate and coarse aggregate) is 1200 kg / m 3 ~2000 kg / m 3 is. For example, the concrete material contains 10% to 30% by weight of cementitious material, 2.5% to 15% by weight of water, 0.005% to 0.75% by weight of air-entraining agent, 20% to 55% by weight of fine aggregate, and 25% to 60% by weight of coarse aggregate.

[0016] The concrete material may further contain any material other than those described above. For example, the concrete material may further contain any additives such as shrinkage reducing agent, water reducing agent, cement dispersant, etc. Also, the concrete material may further contain fiber materials, metal materials, ceramic materials, plastic materials, wood, wood chips, grass, paper, cloth, glass, soil, clay, paint, adhesive, etc.

[0017] In one embodiment, the forming step includes a step of preparing a concrete structure, a step of crushing or pulverizing the concrete structure to a predetermined particle size, a step of mixing the obtained concrete material with water and pouring it into a mold, a step of pre-compressing the mixture of the concrete material and water in the mold, and a step of applying a manufacturing pressure to the pre-compressed preform to manufacture a primary formed body. For example, the step of crushing or pulverizing the concrete structure includes a step of crushing the concrete structure to obtain concrete crushed material and a step of further pulverizing the concrete crushed material to obtain concrete powder. For example, the mixing ratio of the concrete material and water before pre-compression is 1:0.05 to 1:0.1 by weight. The pressure applied for pre-compression is, for example, 1 MPa to 50 MPa, preferably 2 MPa to 30 MPa, 5 MPa to 20 MPa, or 8 MPa to 15 MPa.

[0018] In one embodiment, the post-processing step includes autoclaving the primary molded body. In this specification, "autoclaving" means the operation of placing an object into an autoclave apparatus and then holding the object inside the apparatus for a predetermined time while maintaining a high temperature and pressure inside the apparatus with saturated steam. Hereinafter, the temperature inside the autoclave apparatus during autoclaving will be referred to as the "autoclaving temperature," and the time spent performing autoclaving will be referred to as the "autoclaving time."

[0019] In one embodiment, the autoclave temperature is 100°C to 300°C, and the autoclave time is 4 to 48 hours. For example, the autoclave temperature may be 110°C to 290°C, 120°C to 280°C, 130°C to 270°C, 140°C to 260°C, 150°C to 250°C, 160°C to 240°C, 170°C to 230°C, or 180°C to 220°C. For example, the autoclave time may be 5 to 36 hours, 6 to 32 hours, 7 to 28 hours, or 8 to 24 hours. However, the autoclave temperature and autoclave time are not limited to the above examples. The pressure inside the autoclave apparatus is appropriately determined based on the saturated vapor pressure according to the autoclave temperature. The pressure inside the autoclave apparatus is usually greater than atmospheric pressure. The saturated vapor in the autoclave is preferably saturated water vapor.

[0020] As shown in the experimental examples described below, the inventors have found that by performing autoclave treatment on a molded body, even a molded body formed under very low manufacturing pressure can have its compressive strength significantly improved compared to before autoclave treatment, regardless of the raw material.

[0021] In one embodiment, the post-processing step includes immersing the primary molded body in water and heating the primary molded body after removing it from the water. Hereinafter, a process combining such immersion and heating steps will be referred to as "immersion and heating treatment". The immersion time for immersing the primary molded body in water is, for example, 4 to 96 hours, preferably 5 to 64 hours, 6 to 56 hours, 7 to 52 hours, or 8 to 48 hours. The heat treatment temperature for heating the primary molded body is, for example, 40°C to 200°C, preferably 45°C to 170°C, 50°C to 150°C, 55°C to 140°C, 60°C to 130°C, or 65°C to 120°C. The heat treatment time for heating the primary molded body is, for example, 4 to 96 hours, preferably 5 to 64 hours, 6 to 56 hours, 7 to 52 hours, or 8 to 48 hours.

[0022] The inventors have found that, as shown in the experimental examples described below, immersion heating of a molded body can improve its compressive strength compared to before immersion heating, similar to autoclave treatment.

[0023] In one embodiment, the post-processing step includes either or both of the steps described above: the autoclave treatment step and the immersion heating treatment step.

[0024] In one embodiment, the porosity of the molded article increases before and after the post-processing step. In this specification, "porosity" means the ratio of the volume of voids to the total volume of the molded article, and is determined by methods such as the Archimedes method. For example, the increase in porosity before and after the post-processing step is 1% or more of the porosity of the molded article before the post-processing step, preferably 2% or more, 3% or more, 5% or more, or 10% or more. In one embodiment, there is a positive correlation between the increase in porosity of the molded article before and after the post-processing step and the increase in compressive strength. This makes it possible to provide a molded article with excellent strength despite having a large porosity.

[0025] In one embodiment, the manufacturing pressure in the molding step is 100 MPa or less, preferably less than 100 MPa, and more preferably 90 MPa or less, 80 MPa or less, 70 MPa or less, 60 MPa or less, 50 MPa or less, 40 MPa or less, 30 MPa or less, 20 MPa or less, or 10 MPa or less. The lower the manufacturing pressure, the less energy is required to manufacture the molded body, making the manufacture of the simple molded body simpler and more efficient.

[0026] In one embodiment, the method for manufacturing a molded article further includes a resting step, after the molding step and before the post-processing step, in which the primary molded article is left to stand for a predetermined time. Particularly when the manufacturing pressure is low, if the post-processing step is performed immediately after the molding step to manufacture the primary molded article, cracks and defects may occur in the molded article. By including a resting step, the internal structure of the primary molded article may be stabilized, and the surface of the primary molded article may be stabilized by carbon dioxide in the atmosphere, etc. This makes it possible to suppress the occurrence of cracks and defects caused by the post-processing step.

[0027] In one embodiment, the compressive strength of the molded article increases before and after the post-processing step, with an increase rate of 50% or more. Here, a 50% increase in compressive strength before and after the post-processing step means that the compressive strength after the post-processing step is 1.5 times the compressive strength before the post-processing step. For example, the increase rate in compressive strength may be 100% or more, 150% or more, 200% or more, 250% or more, 300% or more, 350% or more, 400% or more, 450% or more, 500% or more, 550% or more, or 600% or more. The post-processing step can improve the compressive strength. In particular, when the manufacturing pressure is low, a molded article with superior strength can be manufactured using a simple method. In one embodiment, as described above, as the compressive strength of the molded article increases before and after the post-processing step, the porosity of the molded article also increases.

[0028] In one embodiment, the compressive strength of the molded article after the post-treatment step is 18 MPa or higher. A compressive strength of 18 MPa is the minimum performance required for ordinary concrete as specified in JIS A 5308 "Ready-Mixed Concrete". Preferably, the compressive strength of the molded article after the post-treatment step is 21 MPa or higher, which is often used as a standard for the compressive strength of concrete. For example, the compressive strength of the molded article after the post-treatment step is 25 MPa or higher, 30 MPa or higher, 35 MPa or higher, 40 MPa or higher, 45 MPa or higher, or 50 MPa or higher.

[0029] A method for manufacturing a molded article according to one embodiment may include any additional steps. For example, a method for manufacturing a molded article may include steps such as applying pressure to the molded article before or after a post-treatment step to improve the strength of the molded article, heat-treating the molded article (e.g., firing), or blowing carbon dioxide gas onto the molded article.

[0030] <Method for reinforcing molded bodies> In one embodiment, a method for reinforcing a molded body is provided, which includes the step of increasing the compressive strength of a molded body formed by applying manufacturing pressure to a concrete material made from concrete waste as a raw material, by heating the molded body while exposing it to moisture or heating it after exposing it to moisture.

[0031] <Compression molded body> In one embodiment, a compression molded body made from concrete waste is provided, which has a compressive strength of 18 MPa or more and a reduction rate of compressive strength of 30% or less when saturated with water.

[0032] Preferably, the reduction in compressive strength when the molded body is saturated with water is 25% or less, 20% or less, 15% or less, or 10% or less. The smaller the reduction in compressive strength, the better the water resistance of the molded body, and the more the deterioration of strength when exposed to water can be suppressed.

[0033] Molded articles are formed to have any size, shape, structure, density, and weight according to their intended use. Furthermore, molded articles are formed to possess various properties such as strength, rigidity, hardness, water resistance, and heat resistance, depending on their intended use.

[0034] In one embodiment, the void ratio of the compression molded article is 22.6% or more. [Examples]

[0035] Examples of the present invention will be described below with reference to Figures 1 to 7. These examples are not intended to limit the present invention.

[0036] [Concrete materials] Eighteen different types of concrete materials with varying constituent components and compositions were used as raw materials for the molded bodies. Table 1 shows the dry density of each component of the concrete materials. Table 2 shows the identification names, ages, and characteristics of the concrete materials 1-18 used. Table 3 shows the mixing ratio (kg / m³) of each component of the concrete materials 1-18 used. 3 This shows that each of materials 1 to 18 consisted of approximately 20% by weight of cement, approximately 7% by weight of water and optionally an air-entraining agent (AE), approximately 33% by weight of fine aggregate, and approximately 40% by weight of coarse aggregate.

[0037] For the cement material, general Portland cement (OPC) was used, along with optional blast furnace slag powder (B), silica fume (SF), or fly ash (FA). For the fine aggregate, one or more of the following were used: natural sand (NS), blast furnace slag (BS), and limestone sand (LS). For the coarse aggregate, one or more of the following were used: natural gravel (NG), blast furnace slag coarse aggregate (BG), limestone gravel (LG), and road steel slag base course material (BCM). Here, for limestone gravel (LG), one of three types of gravel, LG-A, LG-B, or LG-C, was used.

[0038] [Table 1]

[0039] [Table 2]

[0040] [Table 3]

[0041] As shown in Table 2, concrete materials 1 to 18 were each given an identification name based on their constituent components and composition. For example, the identification name for material 1 is NSNG, and it is a concrete material manufactured by mixing Portland cement (OPC), water, air-entraining agent (AE), natural sand (NS) as fine aggregate, and natural gravel (NG) as coarse aggregate. Materials 2 to 18 are variations of material 1 in which some of the constituent components have been replaced with other components.

[0042] Materials 2-8 are materials in which some or all of the fine aggregate (natural sand NS) and coarse aggregate (natural gravel NG) of Material 1 have been replaced with other fine aggregate and coarse aggregate. Material 2 (BSBCM50) is a material in which approximately half of the NS and NG of Material 1 have been replaced with BS and BCM, respectively. Material 3 (BSBCM100) is a material in which the entire amount of NS and NG of Material 1 has been replaced with BS and BCM, respectively. Material 4 (BSBG50) is a material in which approximately half of the NS and NG of Material 1 have been replaced with BS and BG, respectively. Material 5 (BSBG100) is a material in which the entire amount of NS and NG of Material 1 has been replaced with BS and BG, respectively. Material 6 (LA) is a material in which the entire amount of NS and NG of Material 1 has been replaced with LS and LG-A, respectively. Material 7 (LB) is a material in which the entire amount of NS and NG of Material 1 has been replaced with LS and LG-B, respectively. Material 8 (LC) is obtained by replacing all of the NS and NG in Material 1 with LS and LG-C, respectively.

[0043] Materials 9-16 are variations of Material 1 in which a portion of the cement material (Portland cement OPC) has been replaced with another cement material. Material 9 (B20) is a variation in which approximately 20% by weight of the OPC in Material 1 has been replaced with B. Material 10 (B50) is a variation in which approximately 50% by weight of the OPC in Material 1 has been replaced with B. Material 11 (SF05) is a variation in which approximately 5% by weight of the OPC in Material 1 has been replaced with SF. Material 12 (SF10) is a variation in which approximately 10% by weight of the OPC in Material 1 has been replaced with SF. Material 13 (SF15) is a variation in which approximately 15% by weight of the OPC in Material 1 has been replaced with SF. Material 14 (FA10) is a variation in which approximately 10% by weight of the OPC in Material 1 has been replaced with FA. Material 15 (FA20) is material 1 in which approximately 20% by weight of OPC is replaced with FA. Material 16 (FA30) is material 1 in which approximately 30% by weight of OPC is replaced with FA.

[0044] Materials 17 and 18 are materials in which some or all of the cement (OPC), fine aggregate (NS), and coarse aggregate (NG) of Material 1 are replaced with other cement, fine aggregate, and coarse aggregate, respectively. In Material 17 (B50BSBG50), approximately half of the OPC, NS, and NG of Material 1 are replaced with B, BS, and BG, respectively. In Material 18 (B50BSBG100), approximately half of the OPC of Material 1 is replaced with B, and all of the NS and NG are replaced with BS and BG, respectively.

[0045] [Experimental Example 1] Concrete waste (i.e., concrete rubble) of material 1 (NSNG) was crushed with a jaw crusher to obtain concrete crushed material. Next, the concrete crushed material was further pulverized using a vibratory disc mill with a sieve having a pore size of 300 μm until the maximum particle size was 300 μm, to obtain concrete powder. After a moisture content test was performed on the obtained concrete powder, it was molded into a cylindrical test piece with a diameter of 2 cm and a height of 4 cm for a compressive strength test. Specifically, the concrete powder and water were mixed in a weight ratio of 1:0.08, placed in a steel mold, and compressed at a preliminary compression pressure of 10 MPa. Next, the compressed body was demolded, placed in an still water chamber and sealed, and a manufacturing pressure P = 100 MPa was applied for 3 minutes to obtain a primary molded body. In Experimental Example 1, this primary molded body is the final molded body.

[0046] (Compression strength test) The compressive strength test was performed using a concrete compressive strength testing machine (model UH-1000kNC, manufactured by Shimadzu Corporation). A uniaxial compressive load was applied in the axial direction of the molded body at a loading rate of 10 N / s, and the compressive strength was determined from the observed maximum load. The test was performed immediately after the manufacture of the test specimen. The measured compressive strength was 12.0 MPa.

[0047] [Experimental Example 2] Except for using material 2 (BSBCM50) instead of material 1 (NSNG), a molded body was manufactured under the same conditions as in Experimental Example 1, and a compressive strength test was performed. The measured compressive strength was 12.5 MPa.

[0048] [Experimental Example 3] Except for using material 3 (BSBCM100) instead of material 1 (NSNG), a molded body was manufactured under the same conditions as in Experimental Example 1, and a compressive strength test was performed. The measured compressive strength was 18.3 MPa.

[0049] [Experimental Example 4] (Manufacturing of molded products by autoclave treatment) The primary molded body, manufactured in the same manner as in Experimental Example 1, was left to stand at room temperature for 48 hours, and then autoclaved using an autoclave reactor with a maximum operating pressure of 18 MPa and a maximum temperature of 300°C. The reactor was filled with water to 75% capacity, and the primary molded body was kept submerged in the water. The primary molded body was autoclaved at an autoclave temperature T1 = 180°C for an autoclave time S1 = 8 hours. After autoclaving, the molded body was left to stand at 20°C for 1 day to remove excess water, and the molded body was obtained. No cracks or defects were observed in the obtained molded body. The obtained molded body was subjected to a compressive strength test in the same manner as in Experimental Example 1.

[0050] [Experimental Examples 5-9] In Experimental Examples 5-9, molded bodies were manufactured under the same conditions as in Experimental Example 4, except for the autoclave treatment temperature T1 and autoclave treatment time S1. In Experimental Example 5, T1=180°C and S1=16 hours; in Experimental Example 6, T1=180°C and S1=24 hours; in Experimental Example 7, T1=220°C and S1=8 hours; in Experimental Example 8, T1=220°C and S1=16 hours; and in Experimental Example 9, T1=220°C and S1=24 hours. A compressive strength test was performed on each of the obtained molded bodies in the same manner as in Experimental Example 4. The manufacturing conditions and compressive strengths for Experimental Examples 4-9 are summarized in Table 4. [Table 4]

[0051] [Experimental Examples 10-15] In Experimental Examples 10-15, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 2 (BSBCM50) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 10-15 are summarized in Table 5. [Table 5]

[0052] [Experimental Examples 16-21] In Experimental Examples 16-21, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 3 (BSBCM100) was used instead of Material 1 (NSNG), and compressive strength tests were performed. The manufacturing conditions and compressive strengths for Experimental Examples 16-21 are summarized in Table 6. [Table 6]

[0053] [Experimental Examples 22-27] In Experimental Examples 22-27, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 4 (BSBG50) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 22-27 are summarized in Table 7. [Table 7]

[0054] [Experimental Examples 28-33] In Experimental Examples 28-33, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 5 (BSBG100) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 28-33 are summarized in Table 8. [Table 8]

[0055] [Experimental Examples 34-39] In Experimental Examples 34-39, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 6 (LA) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 34-39 are summarized in Table 9. [Table 9]

[0056] [Experimental Examples 40-45] In Experimental Examples 40-45, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 7 (LB) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 40-45 are summarized in Table 10. [Table 10]

[0057] [Experimental Examples 46-51] In Experimental Examples 46-51, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 8 (LC) was used instead of Material 1 (NSNG), and compressive strength tests were performed. The manufacturing conditions and compressive strengths for Experimental Examples 46-51 are summarized in Table 11. [Table 11]

[0058] [Experimental Examples 52-57] In Experimental Examples 52-57, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 9 (B20) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 52-57 are summarized in Table 12. [Table 12]

[0059] [Experimental Examples 58-63] In Experimental Examples 58-63, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 10 (B50) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 58-63 are summarized in Table 13. [Table 13]

[0060] [Experimental Examples 64-69] In Experimental Examples 64-69, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 11 (SF05) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 64-69 are summarized in Table 14. [Table 14]

[0061] [Experimental Examples 70-75] In Experimental Examples 70-75, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 12 (SF10) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 70-75 are summarized in Table 15. [Table 15]

[0062] [Experimental Examples 76-81] In Experimental Examples 76-81, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 13 (SF15) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 76-81 are summarized in Table 16. [Table 16]

[0063] [Experimental Examples 82-87] In Experimental Examples 82-87, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 14 (FA10) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 82-87 are summarized in Table 17. [Table 17]

[0064] [Experimental Examples 88-93] In Experimental Examples 88-93, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 15 (FA20) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 88-93 are summarized in Table 18. [Table 18]

[0065] [Experimental Examples 94-99] In Experimental Examples 94-99, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 16 (FA30) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 94-99 are summarized in Table 19. [Table 19]

[0066] [Experimental Examples 100-105] In Experimental Examples 100-105, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 17 (B50BSBG50) was used instead of Material 1 (NSNG), and compressive strength tests were conducted. The manufacturing conditions and compressive strengths for Experimental Examples 100-105 are summarized in Table 20. [Table 20]

[0067] [Experimental Examples 106-111] In Experimental Examples 106-111, molded bodies were manufactured under the same conditions as in Experimental Examples 4-9, except that Material 18 (B50BSBG100) was used instead of Material 1 (NSNG), and compressive strength tests were performed. The manufacturing conditions and compressive strengths for Experimental Examples 106-111 are summarized in Table 21. [Table 21]

[0068] As described above, all of the molded articles that underwent autoclave treatment in Experimental Examples 4 to 111 showed compressive strengths exceeding 18 MPa, and even exceeding 21 MPa.

[0069] Figure 1 is a graph comparing the compressive strength of Experimental Examples 1 and 4-9 (using Material 1), Experimental Examples 2 and 10-15 (using Material 2), and Experimental Examples 3 and 16-21 (using Material 3). Regardless of the material used, it was confirmed that the compressive strength of the autoclaved molded body was significantly improved compared to the unautoclaved molded body ("Untreated" in Figure 1), regardless of the autoclave treatment conditions.

[0070] Figure 2 is a graph comparing the compressive strength of molded bodies obtained from various concrete materials that were autoclaved at 180°C for 8 hours in each experimental case. In all cases using materials 1 to 18, the compressive strength was significantly higher than that of the molded bodies in experimental cases 1 to 3, which were not autoclaved. It was confirmed that all molded bodies exceeded 18 MPa and even 21 MPa.

[0071] (Void ratio measurement test) The porosity of the molded bodies obtained in Experimental Examples 1-4, 10, and 16 was determined by the Archimedes method. Specifically, the mass of the molded body saturated with water and the mass of the molded body in a dry state were measured, and the difference was calculated as the porosity. The measured porosities were 22.5% for the molded body in Experimental Example 1, 21.7% for the molded body in Experimental Example 2, 21.8% for the molded body in Experimental Example 3, 24.5% for the molded body in Experimental Example 4, 24.3% for the molded body in Experimental Example 10, and 22.6% for the molded body in Experimental Example 16.

[0072] Figure 3 is a graph comparing the porosity of Experimental Examples 1 and 4 (using Material 1), Experimental Examples 2 and 10 (using Material 2), and Experimental Examples 3 and 16 (using Material 3). It was confirmed that the porosity increased after autoclaving in all cases. The increase in porosity due to autoclaving was 8.9% when comparing Experimental Example 1 and Experimental Example 4 using Material 1, 12.4% when comparing Experimental Example 2 and Experimental Example 10 using Material 2, and 3.5% when comparing Experimental Example 3 and Experimental Example 16 using Material 3. Normally, the porosity tends to decrease as the compressive strength of a molded body increases, but in the molded bodies obtained in Experimental Examples 4, 10, and 16, it was confirmed that both the porosity and compressive strength increased before and after autoclaving. The mechanism of compressive strength improvement in this invention is not yet clear, but it is possible that the increase in porosity is related to the improvement in compressive strength. However, this speculation does not limit the invention.

[0073] (Saturated compressive strength test) The molded bodies obtained in Experimental Examples 4, 10, and 16 were immersed in tap water for approximately 4 days to saturate, and then a compressive strength test was performed. During the saturation process, the mass change of the molded body was observed periodically, and it was considered 100% saturated when a constant mass was observed. The compressive strength test was performed immediately after removing the molded body from the water. The compressive strength of the water-saturated molded bodies was 40.9 MPa for Experimental Example 4, 44.0 MPa for Experimental Example 10, and 35.1 MPa for Experimental Example 16.

[0074] Figure 4 is a graph comparing the compressive strength before and after saturation treatment for experimental examples 4, 10, and 16. In experimental example 4, which used material 1, the compressive strength decreased by 23% before and after saturation; in experimental example 10, which used material 2, the compressive strength decreased by 7% before and after saturation; and in experimental example 16, which used material 3, the compressive strength decreased by 6% before and after saturation.

[0075] [Experimental Examples 112-120] In Experimental Examples 112-120, molded bodies were manufactured under the same conditions as in Experimental Example 4, except that the manufacturing pressures P were set to 90 MPa, 80 MPa, 70 MPa, 60 MPa, 50 MPa, 40 MPa, 30 MPa, 20 MPa, and 10 MPa, respectively, and compressive strength tests were performed.

[0076] In experimental examples 112 (P=20MPa) and 113 (P=10MPa), cracks were observed in the molded bodies when the standing time of the primary molded bodies before autoclaving was short. When the standing time of the primary molded bodies was 48 hours, slight cracks were observed, and when the standing time was 96 hours, no cracks were observed. It is presumed that when the manufacturing pressure P is low, allowing the primary molded bodies to stand for a sufficient amount of time before autoclaving is effective in preventing cracking.

[0077] [Experimental Examples 121-129] In Experimental Examples 121-129, molded bodies were manufactured under various manufacturing pressures P under the same conditions as in Experimental Examples 112-120, except that Material 2 (BSBCM50) was used instead of Material 1 (NSNG), and compression strength tests were performed.

[0078] [Experimental Examples 130-138] In Experimental Examples 130-138, molded bodies were manufactured under various manufacturing pressures P under the same conditions as in Experimental Examples 112-120, except that Material 3 (BSBCM100) was used instead of Material 1 (NSNG), and compression strength tests were performed.

[0079] Table 22 summarizes the manufacturing conditions and compressive strengths for Experimental Examples 112-138. Figure 5 is a graph showing the compressive strength of molded bodies at various manufacturing pressures P for Experimental Examples 4 and 112-120 (Material 1), Experimental Examples 10 and 121-129 (Material 2), and Experimental Examples 16 and 130-138 (Material 3). In particular, within the manufacturing pressure range P ≤ 80 MPa, a general trend was observed where the compressive strength gradually decreased as the manufacturing pressure P decreased. However, even at the minimum manufacturing pressure P = 10 MPa, the compressive strengths of molded bodies for Materials 1-3 all exceeded 18 MPa and even 21 MPa.

[0080] [Table 22]

[0081] [Experimental Example 139] A molded body was manufactured under the same conditions as in Example 4, except that the step of further grinding with a vibratory disc mill until the maximum particle size reached 300 μm was omitted, and a compressive strength test was performed. The concrete powder used contained particles with a particle size greater than 300 μm and 1.18 mm or less, but no particles with a particle size of 300 μm or less. The measured compressive strength was 27.6 MPa.

[0082] [Experimental Example 140] A molded body was manufactured under the same conditions as in Example 4, except that a molded body was produced using concrete powder obtained by mixing a group of particles P1 with a particle size greater than 300 μm but less than or equal to 1.18 mm, obtained by omitting the step of further grinding with a vibratory disc mill until the maximum particle size reached 300 μm, and a group of particles P2 with a particle size of 300 μm or less, obtained by further grinding with a vibratory disc mill until the maximum particle size reached 300 μm, in a weight ratio of 75:25. A compressive strength test was then performed. The measured compressive strength was 35.8 MPa.

[0083] [Experimental Example 141] A molded body was manufactured under the same conditions as in Example 140, except that a particle group P1 with a particle size greater than 300 μm and less than or equal to 1.18 mm and a particle group P2 with a particle size of 300 μm or less were mixed in a weight ratio of 50:50, and a compressive strength test was performed. The measured compressive strength was 42.5 MPa.

[0084] [Experimental Example 142] A molded body was manufactured under the same conditions as in Example 140, except that a particle group P1 with a particle size greater than 300 μm and less than or equal to 1.18 mm and a particle group P2 with a particle size of 300 μm or less were mixed in a weight ratio of 25:75, and a compressive strength test was performed. The measured compressive strength was 46.7 MPa.

[0085] Figure 6 is a graph showing the compressive strength as a ratio of the weight of particle group P1 (particle size greater than 300 μm and 1.18 mm or less) to particle group P2 (particle size 300 μm or less) for experimental examples 4 and 139-142, in which the particle size of the raw material concrete powder was varied. It was confirmed that the compressive strength of the molded body tended to increase as the amount of particle group P2 (smaller particle size) increased. However, it was also confirmed that the molded body of experimental example 139, which does not contain particle group P2 and has the lowest compressive strength, had a compressive strength exceeding 18 MPa and even exceeding 21 MPa. Thus, molded bodies with sufficient compressive strength were obtained even without the fine grinding process.

[0086] [Experimental Example 143] (Manufacturing of molded products by immersion and heat treatment) A primary molded body, manufactured in the same manner as in Experimental Example 1, was immersed in water for a submersion time S2 = 8 hours, and then held in a heating furnace at a heat treatment temperature T2 = 105°C for a heat treatment time S3 = 48 hours to obtain a molded body. After holding the obtained molded body at 20°C for 1 hour for temperature control, a compressive strength test was performed in the same manner as in Experimental Example 1.

[0087] [Experimental Examples 144-154] In Experimental Examples 144-154, molded bodies were manufactured under the same conditions as in Experimental Example 143, except for the immersion time S2, heat treatment temperature T2, and heat treatment time S3. In Experimental Example 144, S2=16 hours, T2=105°C, S3=48 hours; in Experimental Example 145, S2=24 hours, T2=105°C, S3=48 hours; in Experimental Example 146, S2=48 hours, T2=105°C, S3=48 hours; in Experimental Example 147, S2=24 hours, T2=105°C, S3=8 hours; in Experimental Example 148, S2=24 hours, T2=105°C, S3=16 hours; and in Experimental Example 149, S2=24 hours, T2=105°C In experimental example 150, S2=24 hours, T2=105°C, and S3=48 hours were used, in experimental example 151, S2=24 hours, T2=65°C, and S3=48 hours were used, in experimental example 152, S2=24 hours, T2=120°C, and S3=48 hours were used, in experimental example 153, S2=0 hours (i.e., no immersion), T2=120°C, and S3=48 hours were used, and in experimental example 154, S2=48 hours and S3=0 hours (i.e., no heat treatment). A compressive strength test was performed on each of the obtained molded bodies in the same manner as in experimental example 143. The manufacturing conditions and compressive strengths for experimental examples 143 to 154 are summarized in Table 23. [Table 23]

[0088] [Experimental Examples 155-166] In Experimental Examples 155-166, molded bodies were manufactured under the same conditions as in Experimental Examples 143-154, except that Material 2 (BSBCM50) was used instead of Material 1 (NSNG), and compressive strength tests were performed. The manufacturing conditions and compressive strengths for Experimental Examples 155-166 are summarized in Table 24. [Table 24]

[0089] [Experimental Examples 167-178] In Experimental Examples 167-178, molded bodies were manufactured under the same conditions as in Experimental Examples 143-154, except that Material 3 (BSBCM100) was used instead of Material 1 (NSNG), and compressive strength tests were performed. The manufacturing conditions and compressive strengths for Experimental Examples 167-178 are summarized in Table 25. [Table 25]

[0090] Figure 7 is a graph comparing the compressive strength of Experimental Examples 1 and 143-154 (using Material 1), Experimental Examples 2 and 155-166 (using Material 2), and Experimental Examples 3 and 167-178 (using Material 3). Regardless of the material used, it was confirmed that the molded bodies subjected to immersion heat treatment showed improved compressive strength compared to the molded bodies of Experimental Examples 1-3 ("No Treatment" in Figure 7), regardless of the immersion heat treatment conditions. On the other hand, molded bodies subjected to only heat treatment or only immersion treatment ("Heating Only" and "Immersion Only" in Figure 7) did not necessarily show improved compressive strength compared to the molded bodies of Experimental Examples 1-3 ("No Treatment" in Figure 7). Therefore, it was confirmed that the compressive strength of the molded bodies can also be improved by performing both immersion and heat treatment instead of autoclave treatment in Experimental Examples 4-142.

Claims

1. A molding step in which a primary molded body is formed by applying manufacturing pressure to concrete material made from concrete waste as a raw material and compressing it, A resting step of leaving the primary molded body to stand for a predetermined time, After the settling step, a post-processing step is performed in which the primary molded body is subjected to autoclave treatment or immersion heating treatment. Includes, The autoclave treatment temperature for the aforementioned autoclave treatment is 100°C to 300°C. The immersion heating treatment includes the steps of immersing the primary molded body in water and heating the primary molded body after removing it from the water, wherein the heat treatment temperature in the step of heating the primary molded body is 40 to 200°C. The aforementioned concrete material contains particles with a particle size greater than 300 μm and less than or equal to 5 mm. The manufacturing pressure is 10 MPa or more and 100 MPa or less. The maximum operating pressure in the autoclave process is 18 MPa. The porosity of the molded body increases before and after the post-processing step, or the compressive strength of the molded body increases before and after the post-processing step, and the rate of increase is 50% or more and 600% or less. A method for manufacturing a molded product.

2. The concrete material includes at least one of crushed concrete waste and crushed concrete powder. A method for manufacturing a molded article according to claim 1.

3. The autoclave processing time for the aforementioned autoclave processing is 4 to 48 hours. The immersion time in the step of immersing the molded body in water is 4 to 96 hours, and the heat treatment time in the step of heating the molded body is 4 to 96 hours. A method for manufacturing a molded article according to claim 1.

4. The concrete material comprises one or more cement materials selected from the group consisting of Portland cement, blast furnace slag fine powder, silica fume, and fly ash; water; one or more fine aggregates selected from the group consisting of natural sand, blast furnace slag, and limestone sand; and one or more coarse aggregates selected from the group consisting of natural gravel, blast furnace slag coarse aggregate, limestone gravel, and road steel slag base course material. A method for manufacturing a molded article according to any one of claims 1 to 3.

5. The manufacturing pressure in the molding step is less than 50 MPa. A method for manufacturing a molded article according to any one of claims 1 to 4.

6. The aforementioned concrete material contains particles with a particle size of 1.5 mm or less. A method for manufacturing a molded article according to any one of claims 1 to 5.

7. The aforementioned concrete material contains particles with a particle size greater than 300 μm and less than or equal to 1.5 mm. A method for manufacturing a molded article according to any one of claims 1 to 6.

8. The compressive strength of the molded article after the post-processing step is 18 MPa or more and 98 MPa or less. A method for manufacturing a molded article according to any one of claims 1 to 7.

9. The process includes a settling step in which a molded body formed by applying manufacturing pressure to concrete material made from concrete waste as a raw material is left to stand for a predetermined time, and a step in which the molded body after the settling step is subjected to autoclave treatment or immersion heating treatment to increase the compressive strength of the molded body. The autoclave treatment temperature for the aforementioned autoclave treatment is 100°C to 300°C. The immersion heating treatment includes the steps of immersing the molded body in water and heating the molded body after removing it from the water, wherein the heat treatment temperature in the step of heating the molded body is 40 to 200°C. The aforementioned concrete material contains particles with a particle size greater than 300 μm and less than or equal to 5 mm. The manufacturing pressure is 10 MPa or more and 100 MPa or less. The maximum operating pressure in the autoclave process is 18 MPa. Before and after the step of increasing the compressive strength of the molded body, the porosity of the molded body increases, or before and after the step of increasing the compressive strength of the molded body, the rate of increase in the compressive strength of the molded body is 50% or more and 600% or less. A method for reinforcing a molded body.

10. The autoclave processing time for the aforementioned autoclave processing is 4 to 48 hours. The immersion time in the step of immersing the molded body in water is 4 to 96 hours, and the heat treatment time in the step of heating the molded body is 4 to 96 hours. A method for reinforcing a molded article according to claim 9.

11. The aforementioned concrete material contains particles with a particle size of 1.5 mm or less. A method for reinforcing a molded article according to claim 9 or 10.

12. The aforementioned concrete material contains particles with a particle size greater than 300 μm and less than or equal to 1.5 mm. A method for reinforcing a molded article according to any one of claims 9 to 11.

13. A compressed molded concrete material made from concrete waste, The compressive strength is between 18 MPa and 98 MPa, and the reduction in compressive strength when saturated with water is between 0% and 30%. Compression molded body.

14. The porosity is between 22.6% and 24.5%. The compression molded article according to claim 13.

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