Method for producing soil solidified product

Abstract

The present invention provides a method for producing a soil solidified product in which mixing of cement into a clay is well done.　Disclosed is a method for producing a soil solidified product which contains a clay, cement, and a predetermined material, and which is solidified into a predetermined shape. This method for producing a soil solidified product includes: a first step S1 in which a clay is formed into a paste with use of a silica-based inorganic reinforcement admixture that is in a liquid state; and a second step S2 in which cement and the predetermined material are mixed into the clay that has been formed into a paste in the first step S1. The soil solidified product is any one of bricks, building blocks, interlocking blocks, and secondary products.

Description

Manufacturing method of soil solidification product

[0001] The present invention relates to a method for producing a soil solidification product.

[0002] For example, bricks used as building materials are made by kneading and pressing natural viscous soil (clay soil (clay)), drying it to a certain extent, and then firing it.

[0003] Japanese Patent Application Laid-Open No. 2020-153181

[0004] However, with conventional techniques, including the technique of Patent Document 1, when attempting to mix cement with clay, the mixture cannot be mixed sufficiently, resulting in variations in the strength of the solidified soil product (e.g., bricks).

[0005] The present invention has been made in view of the above circumstances, and aims to provide a method for producing a solidified soil product that allows for good mixing of cement with clay.

[0006] In order to achieve the above-mentioned object, one embodiment of the present invention provides a method for producing a solidified soil product, which is formed by solidifying clay, cement, and a predetermined material into a predetermined shape, and includes a first step of making the clay into a paste using a liquefied silica-based inorganic reinforced admixture, and a second step of mixing the cement and the predetermined material with the clay in the paste form.

[0007] According to the present invention, a method for producing a solidified soil product can be provided, which allows for good mixing of cement with clay.

[0008] 1 is a diagram showing an outline of a manufacturing method for a solidified soil formation according to one embodiment of the present invention; FIG. 2 is a flowchart showing a manufacturing method for a solidified soil formation; FIG. 3 is a plan view showing the surface of a test specimen; FIG. 4 is a side view showing the side of a test specimen; FIG. 5 is a diagram showing freeze-thaw test results (mass); FIG. 6 is a diagram showing freeze-thaw test results (mass change rate); FIG. 7 is a diagram showing freeze-thaw test results (appearance observation (number of freeze-thaw cycles: 1 to 4)); FIG. 8 is a diagram showing freeze-thaw test results (appearance observation (number of freeze-thaw cycles: 5 to 8)); FIG. 9 is a diagram showing freeze-thaw test results (appearance observation (number of freeze-thaw cycles: 9 to 12)); FIG. 10 is a diagram showing freeze-thaw test results (appearance observation (number of freeze-thaw cycles: 13 to 15)); FIG. 11 is a diagram showing freeze-thaw test results (appearance observation (number of freeze-thaw cycles: 16 to 19)); FIG. 12 is a diagram showing freeze-thaw test results (appearance observation (number of freeze-thaw cycles: 20 to 23)); FIG. 13 is a diagram showing freeze-thaw test results (appearance observation (number of freeze-thaw cycles: 24 to 26)). FIG. 1 is a diagram showing freeze-thaw test results (appearance observation (27 to 30 freeze-thaw cycles)). FIG. 2 is a diagram showing the appearance (surface) of the test specimen after 15 freeze-thaw cycles. FIG. 3 is a diagram showing the appearance (surface) of the test specimen after 20 freeze-thaw cycles. FIG. 4 is a diagram showing the appearance (surface) of the test specimen after 25 freeze-thaw cycles. FIG. 5 is a diagram showing the appearance (surface) of the test specimen after 30 freeze-thaw cycles. FIG. 6 is a diagram showing the appearance (side) of the test specimen after 30 freeze-thaw cycles.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] FIG. 1 is a diagram showing an outline of a method for producing a soil solidification product according to one embodiment of the present invention.

[0011] In this embodiment, a brick 1 is used as an example of a soil solidification product, and a manufacturing method thereof will be described below. Bricks 1 come in a variety of sizes and are also called by various names depending on the type, use, and size. Here, a rectangular parallelepiped of the size described below (e.g., 200 mm x 100 mm x 60 mm) is the target. Note that soil solidification products other than brick 1 include blocks, interlocking blocks, and secondary products such as curbs (since these are soil solidification products, the sizes are not limited to those described in this specification (the shapes can also be shapes suitable for blocks, interlocking blocks, secondary products, etc., and are not limited to the rectangular parallelepipeds described above)).

[0012] Materials constituting the brick 1 include clay, cement, and a predetermined material. Clay is natural viscous soil (clayey soil), and there are no particular restrictions on the place where it is collected. The above-mentioned clayey soil refers to soil with a particle diameter of 75 μm or less and containing soil particles at 50% or more. It goes without saying that soil, not limited to clay, can also be used as a material constituting the brick 1.

[0013] The clay used in this embodiment has a viscosity somewhere between low and medium, with viscosity levels classified as high, medium, and low. Low viscosity refers to the viscosity of solvent-based adhesives, biological fluids, chemicals, cosmetics, dairy products, inks, various juices, latex, oils, paints and coatings, pharmaceuticals, polymer solutions, rubber solutions, solvents, etc. Medium viscosity refers to the viscosity of hot melt adhesives, ceramic slurries, creams, dairy products, resins, screen printing inks, organic sols, paints, paper coatings, paper pulp, plastic sols, surface coatings, toothpaste, etc. High viscosity refers to the viscosity of asphalt, caulking compounds, chocolate, epoxy, gels, inks (ballpoint pen, offset, lithography), molasses, pastes, peanut butter, putty, roof sealants, sheet molding compounds, tar, etc.

[0014] The aforementioned cement is used, for example, as a building material and is a primary processed product for making concrete or mortar. Examples of the aforementioned predetermined material include sand, sea sand, and dredged soil, and at least one of these is included. The grain size of the sand used in this embodiment is not particularly limited, but medium grain (medium grain sand) is used. The aforementioned sand includes silica sand. The aforementioned predetermined materials, i.e., sand, sea sand, and dredged soil, are materials that can be procured locally where the brick 1 is produced. Furthermore, since clay and soil can also be procured locally, the brick 1 can be used as a locally produced building material, for example, by preparing a silica-based inorganic reinforced admixture, as described below. Using dredged soil as a material can help reduce the extraction of fertile agricultural soil. For example, when producing the brick 1 in a developing country, there is no need to use cultivated soil as a material, which prevents the expansion of uncultivated land.

[0015] The ratio of the above-mentioned materials constituting the brick 1, i.e., clay:cement:predetermined material, is preferably 1:1:4 to 7 (1 part clay, 1 part cement, 4 to 7 parts predetermined material). When the materials are added in such a ratio and stirred, a liquid silica-based inorganic reinforced admixture is also added.

[0016] The silica-based inorganic reinforcing admixture, also known as an inorganic reinforcing material or inorganic admixture, is a so-called cement admixture (cement admixture). The silica-based inorganic reinforcing admixture contains silicon dioxide (e.g., 3.0 kg), calcium chloride (e.g., 7.0 kg), calcium hydroxide (e.g., 5.5 kg), potassium chloride (e.g., 7.0 kg), and other chemicals, and is in powder form (the composition and quantities shown here are exemplary and not limiting). A suitable silica-based inorganic reinforcing admixture is ECO5000 (product name) manufactured by Eiken Co., Ltd. (it has soil solidification properties (including soil and sand containing seawater), allowing the brick 1 to maintain sufficient strength even without firing). The powder form is chosen to reduce transportation costs and ease of use. ECO5000 is diluted with water 30 to 50 times on-site for use (not limited to powder form, but may also be an aqueous solution type). In the case of "ECO5000," the pH value obtained when stirred with water is neutral.

[0017] If all of the above-mentioned materials are simply added and stirred, they will be difficult to mix. Therefore, going through the step described below (first step S1) will enable the cement to be mixed well with the clay.

[0018] The following description will be made with reference to Fig. 2. Fig. 2 is a flowchart showing a method for manufacturing a solidified soil product. That is, the flowchart shows a method for manufacturing, for example, a brick 1. The brick 1 is manufactured by sequentially performing a first step S1 to a fifth step S5.

[0019] The first step S1 is a step of turning clay into a paste using a liquefied silica-based inorganic reinforced admixture. Specifically, the powdered silica-based inorganic reinforced admixture is liquefied by adding an appropriate amount of water to the silica-based inorganic reinforced admixture. The ratio of clay to silica-based inorganic reinforced admixture is 1 part clay to 0.4 to 0.6 parts silica-based inorganic reinforced admixture. In this embodiment, the ratio is set so that 1 part clay to 0.5 parts silica-based inorganic reinforced admixture. The above ratio of silica-based inorganic reinforced admixture is set within a range of plus or minus 10% from 0.5. The lower limit of 0.4 is set in consideration of reactivity with cement, and the upper limit of 0.6 is set in consideration of cost.

[0020] After the silica-based inorganic reinforced admixture is converted from powder to liquid, the liquid silica-based inorganic reinforced admixture and clay are placed in a mixer 11 and stirred for 3 to 4 minutes to produce a paste-like clay (paste-like clay 2). Note that the above-mentioned stirring time (3 to 4 minutes) varies depending on the amount of clay and the amount of the liquid silica-based inorganic reinforced admixture, and is therefore an example of the stirring time.

[0021] The second step S2 is a step of mixing cement and predetermined materials with the pasty clay. Specifically, this is a step of mixing the cement and predetermined materials with the pasty clay 2 in a mixer 12 to create a mixed product (not shown). In this embodiment, mixing is performed so that the moisture content in the mixer 12 is measured at 55 to 60% (as an example, a moisture content of 60% is set as the upper limit). Note that the second step S2 may be a step of first adding cement to the pasty clay (pastey clay 2) and stirring (stirring time is 1 to 2 minutes, 3 to 5 minutes depending on the amount), and then mixing the predetermined materials after this stirring.

[0022] The third step S3 is a step of pouring the mixture (not shown) that has been mixed in the mixer 12 into a predetermined manufacturing machine 14, and then applying vibration and pressure from above, for example. Specifically, this is a step of pouring the mixture (not shown) from the mixer 12 into the manufacturing machine 14 using, for example, a conveyor 13, and then producing the mixture without firing it by vibration and pressure from above, for example.

[0023] The manufacturing machine 14 described above is a brick manufacturing machine (movable and assembled) that employs brick mold frames that have been subjected to a special surface treatment technology. This machine structure allows for smoothing the surface of the bricks 1, thereby reducing the number of small pores on the surface and suppressing the overall water absorption rate of the bricks 1 (enhancing the strength of the bricks 1). The manufacturing machine 14 is configured without using a kiln. The absence of a kiln provides the following benefits: (1) reduction in emissions of air pollutants, including CO2 emissions and particulate matter; (2) reduction in health damage, deaths, and agricultural land pollution caused by air pollutants; and (3) reduction in serious health damage (respiratory, digestive, and eye-related diseases) caused by high-temperature kiln smoke.

[0024] The fourth step S4 is a step of performing water spray curing after the completion of the third step S3. Specifically, this step is a step of performing water spray curing (sprinkling water / water spray curing) on ​​the bricks 1 completed in the third step S3 for, for example, about one week.

[0025] The fifth step S5 is a storage step after the completion of the fourth step S4. Specifically, the bricks 1 completed in the fourth step S4 are stored for, for example, another week. After the fifth step S5 is completed, the bricks 1 are shipped.

[0026] The brick 1 manufactured through the first step S1 to the fifth step S5 in this order has a sufficient load-bearing capacity (strength measurement result). If the load-bearing capacity is expressed in Newtons (N) or, for example, pounds per square inch (PSI) as used in Bangladesh, the brick 1 has a result of approximately 24N, or 3,500PSI. For reference, in Nepal, a result of 15N is acceptable, and the result obtained when using Nepalese clay and Japanese sand was 15N.

[0027] Next, a test specimen manufactured for the freeze-thaw test described later will be described with reference to Figures 3 and 4. Figure 3 is a plan view showing the surface of the test specimen, and Figure 4 is a side view showing the side of the test specimen.

[0028] 3 and 4, five specimens 50-1 to 50-5 are formed in the shape of a rectangular parallelepiped with dimensions of 200 mm x 100 mm x 60 mm. The specimens 50-1 to 50-5 are the same as the brick 1 manufactured by sequentially going through the first step S1 to the fifth step S5. A freeze-thaw test was conducted on these specimens 50-1 to 50-5, and the results are shown in FIGS. 5 to 19.

[0029] Fig. 5 shows the results of the freeze-thaw test (mass), Fig. 6 shows the results of the freeze-thaw test (mass change rate), and Figs. 7 to 14 show the results of the freeze-thaw test (appearance observation), of which Fig. 7 shows the results of freeze-thaw cycles from 1 to 4, Fig. 8 shows the results of freeze-thaw cycles from 5 to 8, Fig. 9 shows the results of freeze-thaw cycles from 9 to 12, Fig. 10 shows the results of freeze-thaw cycles from 13 to 15, Fig. 11 shows the results of freeze-thaw cycles from 16 to 19, Fig. 12 shows the results of freeze-thaw cycles from 20 to 23, Fig. 13 shows the results of freeze-thaw cycles from 24 to 26, and Fig. 14 shows the results of freeze-thaw cycles from 27 to 30. Fig. 15 is a diagram showing the appearance (surface) of the test specimen after 15 freeze-thaw cycles, Fig. 16 is a diagram showing the appearance (surface) of the test specimen after 20 freeze-thaw cycles, and Fig. 17 is a diagram showing the appearance (surface) of the test specimen after 25 freeze-thaw cycles. Fig. 18 is a diagram showing the appearance (surface) of the test specimen after 30 freeze-thaw cycles, and Fig. 19 is a diagram showing the appearance (side) of the test specimen after 30 freeze-thaw cycles.

[0030] The test method was in accordance with 5.5 Freeze Damage Test of JIS A 5208 (clay straw), and the details of the test are as follows. <Water absorption process> The test specimen was immersed in fresh water at a temperature of 20±2°C for 24 hours, wiped with a wet cloth, and then the mass was measured to the nearest 0.1 g. <Freeze-thaw conditions> The test specimen was left to stand in a thermo-humidistat chamber at a temperature of -20±3°C for 18 hours or more, and then immersed in water at a temperature of 20±2°C for 6 hours. Thereafter, it was wiped with a wet cloth, the mass was measured to the nearest 0.1 g, and then the appearance was observed (for the presence or absence of cracks, peeling, and defects). This operation was counted as one cycle. <Number of freeze-thaw cycles> The number of freeze-thaw cycles was 30. <Calculation of mass change rate> The mass change rate was calculated using the following formula and rounded to one decimal place. ΔM = ((M ｎ -M ０ ) / M ０ ) × 100 where ΔM: mass change rate (%) M ０ : Mass of the test piece after water absorption (g) M ｎ : Mass (g) of the test specimen immediately after the specified number of times

[0031] As test results, the freeze-thaw test results (mass) are shown in Figure 5. The freeze-thaw test results (mass change rate) are shown in Figure 6. The freeze-thaw test results (appearance observation) are shown in Figures 7 to 14.

[0032] The appearance (surface) of the test specimen after 15 freeze-thaw cycles is as shown in Figure 15. The appearance (surface) of the test specimen after 20 freeze-thaw cycles is as shown in Figure 16. The appearance (surface) of the test specimen after 25 freeze-thaw cycles is as shown in Figure 17. The appearance (surface and side) of the test specimen after 30 freeze-thaw cycles is as shown in Figures 18 and 19.

[0033] From the above test results, it can be said that the brick 1 (test specimens 50-1 to 50-5) can prevent spalling caused by repeated freezing and thawing. Therefore, in addition to building materials, it can also be applied to soil hardening pavement, and the above-mentioned blocks, interlocking blocks, secondary products, etc. will be useful.

[0034] Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within the scope of achieving the object of the present invention are included in the present invention.

[0035] In summary, a method for manufacturing a solidified soil structure to which the present invention is applied is sufficient as long as it has the following configuration, and can take various forms. That is, a method for manufacturing a solidified soil structure to which the present invention is applied (e.g., a method for manufacturing brick 1 shown in FIG. 1) is sufficient as long as it is a method for manufacturing a solidified soil structure (e.g., brick 1 shown in FIG. 1) that contains clay (e.g., the clay shown in FIG. 1), cement (e.g., the cement shown in FIG. 2), and a predetermined material (e.g., the predetermined material shown in FIG. 2) and is solidified into a predetermined shape (e.g., a rectangular parallelepiped shown in FIGS. 3 and 4), and includes: a first step (e.g., first step S1 in FIG. 2) of making the clay into a paste (e.g., pasty clay 2 in FIG. 1) using a liquefied silica-based inorganic reinforced admixture (e.g., the liquefied silica-based inorganic reinforced admixture in FIG. 1); and a second step (e.g., second step S2 in FIG. 2) of mixing the cement and the predetermined material with the pasty clay (e.g., pasty clay 2 in FIG. 1). According to the present invention, a method for producing a solidified soil product can be provided in which the first and second steps result in good mixing of cement with clay.

[0036] Furthermore, in the method for producing a solidified soil product to which the present invention is applied (for example, the method for producing brick 1 shown in Fig. 1), the ratio of the clay to the silica-based inorganic reinforced admixture is preferably 1:0.4 to 0.6. According to the present invention, by setting the ratio of the clay to the silica-based inorganic reinforced admixture to 1:0.4 to 0.6, a better method for producing a solidified soil product can be provided.

[0037] Furthermore, in the method for manufacturing a solidified soil product to which the present invention is applied (for example, the method for manufacturing the brick 1 shown in FIG. 1 ), it is preferable that the ratio of the cement to the predetermined material is 1 part cement to 4 to 7 parts predetermined material. According to the present invention, by setting the ratio of the cement to 4 to 7 parts predetermined material, a better method for manufacturing a solidified soil product can be provided.

[0038] In addition, in the method for manufacturing a solidified soil formation to which the present invention is applied (for example, the method for manufacturing the brick 1 shown in Fig. 1), it is preferable that the predetermined material includes at least one of sand, sea sand, and dredged soil. According to the present invention, by including at least one of sand, sea sand, and dredged soil as the predetermined material, a better method for manufacturing a solidified soil formation can be provided.

[0039] Furthermore, in the method for manufacturing a solidified soil product to which the present invention is applied (for example, a method for manufacturing the brick 1 shown in FIG. 1 or other products), the solidified soil product is preferably any one of a brick, a block, an interlocking block, and a secondary product. According to the present invention, a method for manufacturing a brick, a block, an interlocking block, a secondary product, etc. can be provided.

[0040] Furthermore, a manufacturing method of a solidified soil product to which the present invention is applied (for example, a manufacturing method of brick 1 shown in FIG. 1 ) preferably further includes the following: the second step is a step of mixing the cement and the predetermined material with the pasty clay to prepare an agitated product (for example, second step S2 of preparing an agitated product by mixing in mixer 13 in FIG. 1 ); a third step of pouring the agitated product into a predetermined manufacturing machine and subjecting it to vibration and pressure (for example, third step S3 in FIG. 2 ); and a fourth step of performing watering and curing after the third step (for example, fourth step S4 in FIG. 2 ). According to the present invention, by further carrying out the third and fourth steps, a better manufacturing method of a solidified soil product can be provided.

[0041] REFERENCE SIGNS LIST 1: Brick 2: Paste clay 11: Agitator 12: Mixer 13: Conveyor 14: Manufacturing machine 50-1 to 50-5: Test specimen

Claims

1. A method for manufacturing a solidified soil product which contains clay, cement and a specified material and is formed by solidifying the clay into a specified shape, comprising: a first step of turning the clay into a paste using a liquefied silica-based inorganic reinforced admixture; and a second step of mixing the cement and the specified material with the clay in the paste form.

2. The method for producing a soil solidification product according to claim 1, wherein the ratio of said clay to said silica-based inorganic reinforced admixture is 1 part clay to 0.4 to 0.6 parts silica-based inorganic reinforced admixture.

3. The method for manufacturing a soil solidification product according to claim 1, wherein the ratio of the cement to the specified material is 1 part of the cement to 4 to 7 parts of the specified material.

4. The method for manufacturing a soil solidification product according to claim 3, wherein the specified material includes at least one of sand, sea sand, and dredged soil.

5. The method for manufacturing a soil solidification product according to claim 1, wherein the soil solidification product is any one of a brick, a block, an interlocking, and a secondary product.

6. The method for producing a soil solidification product as described in claim 1, further comprising: a third step of pouring the mixed material into a specified manufacturing machine and subjecting it to vibration and pressure; and a fourth step of performing water spray curing after the third step, wherein the second step is a step of mixing the cement and the specified material with the clay in a paste form to produce a mixed material.