Sandbag and method for manufacturing the same

Abstract

To provide a sandbag which is lightweight, is easily transported, is excellent in shape followability, is simply disposed, and prevents degeneration even when stored over a long period of time.SOLUTION: A sandbag is obtained by filling the inside of a bag having water permeability with a filler composed of (A) 30 mass% or more and 80 mass% or less of porous ceramic having a grain size by sieve classification of 75 μm or less, and (B) a clastic material having a grain size by sieve classification of more than 75 μm. (B) The clastic material contains (B') a clastic material having a grain size by sieve classification of more than 75 μm and 1,000 μm or less, 20 mass% or more of (B') the clastic material is preferably contained in the total filler, and (B) the clastic material preferably contains a porous ceramic. In (A) the porous ceramic having the grain size by sieve classification of 75 μm or less, a pore of a micrometer order having a pore diameter of more than 10 nm and 1,000 nm or less and a pore of a micrometer order having a pore diameter of more than 1 μm and 70 μm or less preferably exist.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to sandbags and a method for manufacturing sandbags.

Background Art

[0002] When a large amount of water flows out, such as due to a river flood, a rupture of a water pipe due to an earthquake, or a water leak from a water storage tank, sandbags filled with soil, gravel, mountain sand, etc. in a polyethylene bag or the like have been conventionally used to block the flowing water.

[0003] However, the soil in the bag is heavy and difficult to transport, and due to the property of solidifying when absorbing water, it is difficult to deform freely along the outer shape of the bag, and there is a problem that water can penetrate through the gaps between the arranged or stacked sandbags.

[0004] Therefore, in Patent Document 1, a modified polymer compound having high water absorbency is supported by a flexible support and contained in a water-permeable bag-like body, and a sandbag with reduced weight during transportation and having shape followability has been proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the case of conventional sandbags filled with soil, gravel, mountain sand, etc., if the soil inside the bag is taken out, it can be disposed of. However, in the sandbag proposed in Patent Document 1, since a water-absorbing polymer is used, there is a problem that treatment such as separation of the contents and incineration is required for the disposal of used sandbags. In addition, there is also a problem that soil containing organic components and water-absorbing polymers may rot or generate algae and mold during long-term storage.

[0007] Therefore, an object of the present invention is to provide a sandbag that is lightweight, easy to carry, excellent in shape followability, easy to dispose of, and less likely to deteriorate even after long-term storage.

Means for Solving the Problems

[0008] In order to solve the above problems, the sandbag and the method for manufacturing the sandbag according to an embodiment of the present invention have the following configurations. (1) A sandbag comprising a filler composed of (A) 30% by mass or more and 80% by mass or less of porous ceramics having a particle size of 75 μm or less by sieving classification and (B) crushed debris having a particle size exceeding 75 μm by sieving classification, filled in a bag having water permeability. (2) The sandbag according to (1) above, wherein the (B) crushed debris contains (B') crushed debris having a particle size exceeding 75 μm and 1000 μm or less by sieving classification, and the (B') crushed debris is contained in an amount of 20% by mass or more based on the total filler. (3) The sandbag according to (1) or (2) above, wherein the (B) crushed debris contains porous ceramics. (4) The sandbag according to any one of (1) to (3) above, wherein the porous ceramics having a particle size of 75 μm or less by sieving classification in (A) have pores in the nanometer order with a pore diameter exceeding 10 nm and 1000 nm or less and pores in the micrometer order with a pore diameter exceeding 1 μm and 70 μm or less. (5) The sandbag according to any one of (1) to (4) above, wherein the permeability coefficient of the filler measured according to the variable water level permeability test described in JIS A1218:2009 is 1.0×10 -5 cm / s or less. (6) The sandbag according to any one of (1) to (5) above, wherein the bag is a woven fabric of natural fiber or fiber having biodegradability. (7) Firing a mixture containing clay and organic sludge to obtain (A) porous ceramics having a particle size of 75 μm or less by sieving classification. Obtaining a packing comprising (A) 30% by mass or more and 80% by mass or less of porous ceramics having a particle size of 75 μm or less as determined by sieve classification, and (B) debris having a particle size of more than 75 μm as determined by sieve classification; and Filling the filling material into a water-permeable bag; A method for manufacturing a sandbag, comprising: Effect of the Invention

[0009] The sandbag of one embodiment of the present invention contains porous ceramics with small particle size, and the content of the ceramics is within a specified range, so that the sandbags are lightweight, have excellent shape conformability, and do not easily form lumps even when they absorb moisture, making it easy to line up or stack the sandbags without gaps. In addition, the sandbags can be disposed of by simply scattering the filling material on the ground surface, and have the effect of not easily deteriorating even when stored for a long period of time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Sandbags according to exemplary embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[0011] The sandbag of this embodiment is a sandbag in which a permeable bag is filled with a filling material consisting of (A) 30 mass% or more of porous ceramics having a particle size of 75 μm or less as determined by sieve classification, and (B) crushed material having a particle size of more than 75 μm as determined by sieve classification.

[0012] (Porous ceramics with particle size of 75μm or less as determined by sieve classification) In this embodiment, (A) the porous ceramics having a particle size of 75 μm or less as determined by sieve classification is a ceramics made up of particles that have a large number of pores in them and pass through a sieve with openings of 75 μm.

[0013] As a raw material for ceramics, a mixture of clay and at least one selected from the group consisting of organic sludge, diatomaceous earth, and foaming agents is used. By blending one selected from the group consisting of organic sludge, diatomaceous earth, and foaming agents with clay and firing, the ceramics can be made porous. In particular, from the viewpoint that pores in the nanometer order with a pore diameter exceeding 10 nm and not exceeding 1000 nm and pores in the micrometer order with a pore diameter exceeding 1 μm and not exceeding 70 μm can be easily formed in the obtained ceramics, it is preferable to fire a mixture containing at least clay and organic sludge.

[0014] Clay is a mineral material showing a clay-like property generally used as a ceramic raw material and is other than diatomaceous earth. As the clay, known ones conventionally used for ceramics can be used. It is composed of a mineral composition such as quartz, feldspar, or other clay-based materials, and the constituent minerals are mainly kaolinite and preferably include halloysite, montmorillonite, illite, bentonite, or pyrophyllite. Among them, frog-eye clay etc. can be mentioned as preferable ones. The clay can be blended alone or in appropriate combination of two or more kinds.

[0015] Organic sludge is sludge containing organic substances as the main component. Any organic sludge can be used, and activated sludge derived from wastewater treatment such as sewage or factories is preferable. The activated sludge is discharged from a wastewater treatment facility using the activated sludge method through a coagulation and dehydration process. By using organic sludge, the organic substances of the organic sludge are burned out in the firing process, and pores in the nanometer order and pores in the micrometer order can be efficiently formed by the path when vaporizing from the fired body. Furthermore, the activated sludge derived from wastewater treatment, which was previously regarded as waste, can be reused as a raw material. The water content of the organic sludge is preferably, for example, 5 to 90% by mass of water with respect to the total mass of the organic sludge, more preferably 60 to 90% by mass, and even more preferably 65 to 85% by mass. If it is within the above range, mixing into the mixture is easy.

[0016] When using organic sludge, the content of the organic sludge in the mixture can be determined in consideration of the moldability of the mixture and the like. For example, it is preferably 0.1 to 30% by mass, more preferably 5 to 20% by mass, and even more preferably 5 to 15% by mass based on the total mass of the mixture. If the content of the organic sludge in the mixture is within the above range, the mixture has appropriate fluidity and plasticity and can be smoothly molded without clogging the molding device.

[0017] The mixing device used in the mixing step of the mixture is not particularly limited, and a known mixing device can be used. Examples of the mixing device include kneaders such as a mix muller (manufactured by Shin To Kogyo Co., Ltd.), a kneader (manufactured by Moriya Co., Ltd.), and a mixer (manufactured by Nittetsu Kagaku Co., Ltd.).

[0018] The mixture may be formed into a molded body in an appropriate shape such as a columnar shape, a plate shape, a granular shape, or a pellet shape using a known molding device such as a vacuum kneading molding machine, a flat plate press molding machine, or a flat plate extrusion molding machine. By firing such a molded body, a porous ceramic mass can be obtained.

[0019] Before firing, the molded body may be dried if necessary. The drying operation can be performed using a known method. For example, the molded body may be naturally dried at room temperature (for example, around 20 to 30 °C as a guide), or may be dried by treating it in a hot air drying furnace at 50 to 220 °C for an arbitrary time.

[0020] The firing process is not particularly limited, and known methods can be used. For example, there is a method of firing at an arbitrary temperature using a continuous sintering furnace such as a roller hearth kiln or a batch sintering furnace such as a shuttle kiln. Among them, from the viewpoint of productivity, it is preferable to use a continuous sintering furnace for the firing operation. The firing temperature (maximum reaching temperature) can be determined according to the properties of the mixture, etc., and is, for example, 850°C to 1200°C. If the firing temperature is at or above the above lower limit value, when organic sludge is used in the mixture to be fired, the odor components derived from the organic sludge are thermally decomposed and eliminated, and most of the organic substances in the organic sludge volatilize and the weight is reduced. If it exceeds the above upper limit value, the vitrification of the entire ceramic structure may progress and the pores may be blocked.

[0021] The ceramics obtained by the above process become porous ceramics having a large number of pores. By becoming porous, the apparent density decreases and the weight becomes lighter, improving transportability, etc. On the other hand, since a large amount of moisture can be contained in the ceramics, the weight during actual use increases, and it can be used as a sandbag that can withstand water pressure. Also, generally, when fine particles absorb moisture, they become a Bingham fluid that does not flow until a certain shear force (yield stress) is applied. However, fine particles that have taken in water in a large number of pores have a higher volume fraction of water compared to the case of fine particles without pores, and exhibit an effect of reducing the yield stress. For this reason, a sandbag with high shape followability can be obtained even after being wetted with water. The apparent density (bulk density) of the porous ceramics obtained by the above process is, for example, 0.75 g / cm 3 or more and 1.0 g / cm 3 or less. Also, the BET specific surface area of the porous ceramics obtained by the above process is, for example, 0.4 m 2 / g or more and 2.0 m 2 / g or less.

[0022] The porous ceramics preferably have pores in the nanometer order with a pore diameter exceeding 10 nm and not exceeding 1000 nm, and pores in the micrometer order with a pore diameter exceeding 1 μm and not exceeding 70 μm. The pores in the micrometer order reduce the apparent density, while the pores in the nanometer order significantly improve the water retention rate by capillary action, greatly increasing the weight when absorbing water, and enabling the soil bag to withstand a higher water pressure.

[0023] In addition, the pore diameter of the pores can be measured by performing image processing according to the scale from the image data obtained by scanning electron microscope observation. Specifically, the pore diameter of the pores of the granular material is the value obtained by measuring the equivalent circle diameter of the pores existing on the surface of the granular material using an electron microscope.

[0024] The pores formed in the porous ceramics may be independent of each other or may be communicating pores communicating with each other.

[0025] The porous ceramics obtained as described above may be in the form of a lump. In this embodiment, for example, by classifying after crushing the lump, (A) porous ceramics with a particle size of 75 μm or less by sieving classification can be obtained. More specifically, the lump-shaped porous ceramics obtained by firing are crushed and pulverized with a hammer mill, a biaxial rotary crusher, a jet mill, a ball mill, or an edge runner mill, etc., and sieved to those with a particle diameter of 75 μm or less. Also, it may be sieved, the large granular materials with a particle diameter exceeding 75 μm are pulverized again, and sieved to those with a particle diameter of 75 μm or less. In this way, porous ceramics with a particle size of 75 μm or less by sieving classification can be manufactured. Regarding the porous ceramics (A) with a particle size of 75 μm or less by sieving classification, the lower limit of the particle size is not particularly limited as long as the porosity can be maintained, but from the viewpoints of ease of maintaining the porosity and difficulty of leaking out from the weave of the bag, it is preferable to use those with a particle size of 5 μm or more by sieving classification.

[0026] (Crushed debris) In this embodiment, the (B) crushed debris is not particularly limited, and various crushed debris with a particle size exceeding 75 μm by sieving classification, such as sand, gravel, and ceramics, can be used. In particular, the crushed product of the porous ceramics manufactured by the above method can also be used, and the surplus with a particle size exceeding 75 μm by sieving classification generated as a result of sieving the porous ceramics with a particle size of 75 μm or less by (A) sieving classification can also be used. By including porous ceramics in the (B) crushed debris, the apparent density is further reduced, making it lighter and improving the transportability. On the other hand, since a large amount of moisture can be contained in the ceramics, the weight during actual use increases, and it can be used as a sandbag that can withstand water pressure. Among the (B) crushed debris, a part may be porous ceramics, but by making all of them porous ceramics, the above effects can be more strongly expressed.

[0027] Furthermore, it is preferable that the (B) crushed debris contains (B') crushed debris with a particle size exceeding 75 μm and not exceeding 1000 μm by sieving classification. For example, the (B) crushed debris may be gravel sieved to a particle size exceeding 75 μm and not exceeding 1000 μm by sieving classification, or the surplus generated as a result of sieving the porous ceramics with a particle size of 75 μm or less by (A) sieving classification may be further sieved using a sieve with an opening of 1000 μm or less. By including (B') crushed debris in the (B) crushed debris, a sandbag with even better shape followability can be obtained.

[0028] (Filling material) The filler of this embodiment is a filler composed of (A) 30% by mass or more and 80% by mass or less of porous ceramics with a particle size of 75 μm or less by sieving classification, and (B) crushed debris with a particle size exceeding 75 μm by sieving classification. By containing 30% by mass or more of fine particles with a particle size of 75 μm or less by sieving classification, a sandbag with high water stopping performance can be obtained. Further, since the content of the fine particles is 80% by mass or less and the fine particles are porous ceramics, it is possible to prevent the crushed debris from absorbing moisture and clumping together, and it becomes easy to arrange or stack wet sandbags without gaps. The amount of porous ceramics with a particle size of 75 μm or less by sieving classification in the filler may be 35% by mass or more or 40% by mass or more, and may be 75% by mass or less or 70% by mass or less.

[0029] The content of the (B) crushed debris in the filler of this embodiment is not particularly limited. As described above, the (B) crushed debris preferably contains (B') crushed debris with a particle size exceeding 75 μm and 1000 μm or less by sieving classification. In this case, the (B') crushed debris may be contained in an amount of 20% by mass or more, 25% by mass or more, or 30% by mass or more based on the total amount of the filler. By containing 20% by mass or more of the (B') crushed debris based on the total amount of the filler, a sandbag with even better shape followability can be obtained.

[0030] Further, the filler may be composed of (B) crushed debris for the remainder excluding (A), or may contain other components other than (A) and (B) within a range that does not inhibit the effects of the sandbag according to this embodiment. Specifically, the filler may contain 1% by mass or less of other components other than (A) and (B), such as heat-treated cotton and sawdust.

[0031] Also, in this embodiment, the permeability coefficient of the filler measured according to the variable water level permeability test described in JIS A1218:2009 is, for example, 1.0×10 -4 cm / s or less, 1.0×10 -5 cm / s or less, or 1.0×10 -6 cm / s or less. The permeability coefficient is 1.0×10 -4cm / s or less, particularly 1.0×10 -5 cm / s or less, a sandbag having high water-stopping performance can be obtained. As described above, the filler of the present embodiment can easily secure excellent water-stopping performance by containing a predetermined amount or more of fine particles having a particle size of 75 μm or less by sieving classification.

[0032] (Bag) The bag of the present embodiment is not particularly limited as long as it is a bag having water permeability, and examples thereof include woven fabrics, knitted fabrics, and non-woven fabrics made of natural fibers such as hemp and cotton, and synthetic fibers such as polyethylene fibers, formed into a bag shape. In particular, if it is a woven fabric made of natural fibers or fibers having biodegradability such as polylactic acid, polyhydroxybutyric acid, and poly(butylene adipate-co-butylene terephthalate), the used sandbag can be disposed of by leaving it on the ground as a bag or burying it in the soil, and the process of taking out the filler in the bag and spreading it can be omitted. In addition, by manufacturing the bag with a woven fabric, it has sufficient strength as a sandbag for a sandbag and can suppress the outflow of fine particles outside the bag, which is preferable. Note that a sandbag that can be repeatedly used may be used by using a synthetic fiber with high durability as the material of the bag.

[0033] (Method for manufacturing a sandbag) The technology of the present disclosure also has an aspect as a method for manufacturing a sandbag. That is, the method for manufacturing a sandbag according to the present embodiment is firing a mixture containing clay and organic sludge to obtain (A) porous ceramics having a particle size of 75 μm or less by sieving classification, obtaining a filler composed of 30% by mass or more and 80% by mass or less of (A) porous ceramics having a particle size of 75 μm or less by sieving classification and (B) crushed debris having a particle size exceeding 75 μm by sieving classification, and filling the filler into a bag having water permeability, and may include. The effects of using organic sludge in the raw material mixture before firing are as described above.

[0034] In addition, the method for manufacturing a sandbag according to the present embodiment is Firing a mixture containing clay and organic sludge to obtain a porous ceramic mass, and crushing the mass to obtain the porous ceramics having a particle size of 75 μm or less by the above (A) sieving classification, which may include. Once the massive porous ceramics are obtained, by crushing them, it is easy to obtain those having excellent homogeneity as the porous ceramics having a particle size of 75 μm or less by (A) sieving classification.

[0035] Further, the method for manufacturing a sandbag according to the present embodiment is crushing the mass to separate it into the porous ceramics having a particle size of 75 μm or less by the above (A) sieving classification and surplus materials, and using at least a part of the surplus materials as crushed materials having a particle size exceeding 75 μm by the above (B) sieving classification, which may include. In particular, it is preferable that the surplus materials used as the above (B) crushed materials are those sieved using a sieve having an opening of 1000 μm or less. Thus, in the manufacturing method according to the present embodiment, the steps can be simplified by using materials made of the same material for the porous ceramics having a particle size of 75 μm or less by (A) sieving classification and the crushed materials having a particle size exceeding 75 μm by (B) sieving classification.

Example

[0036] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following description.

[0037] <Clay> As the clay, frog-eye clay (produced in Gifu Prefecture) was used.

[0038] <Organic sludge> As the organic sludge, activated sludge discharged from the wastewater treatment facility by the activated sludge method of a dyeing factory (Komatsu Matele Co., Ltd.) through the coagulation and dehydration processes was used. The organic matter content (based on solid content) of this activated sludge was 83% by mass, the water content was 85% by mass, and the average particle size was 2.6 μm.

[0039] <Foaming agent> As the foaming agent, cast iron slag was used. This cast iron slag is SiO 2 , Al 2 O 3 , CaO, Fe 2 O 3 , FeO, MgO, MnO, K 2 O and Na 2 O, which is particulate ductile cast iron slag (screened, with a diameter of 10 mm or less) with the above components as the main components.

[0040] <Diatomaceous earth> As the diatomaceous earth, the material obtained by pulverizing the waste after being used as a tile for housing (particle size 0.1 mm to 1.2 mm) was used.

[0041] <Gravel> Gravel with a particle size of 40 mm or less sold at the home center (DCM Carma 21 Komatsu store) in Komatsu City, Ishikawa Prefecture was used.

[0042] <Mountain sand> Mountain sand sold at the home center (DCM Carma 21 Komatsu store) in Komatsu City, Ishikawa Prefecture was used.

[0043] The physical property values were measured by the following methods.

[0044] <Particle size by sieving classification> The particle size of the filler was determined by sieving the sample. Those passing through a sieve with an opening of 75 μm were classified as 75 μm or less (small), those not passing through a sieve with an opening of 75 μm but passing through a sieve with an opening of 1000 μm were classified as more than 75 μm to 1000 μm or less (medium), and those not passing through a sieve with an opening of 1000 μm were classified as more than 1000 μm (large).

[0045] <Permeability coefficient (falling head method)> Based on the JIS A1218:2009 method for testing the permeability of soil, the value measured in accordance with the constant-head permeability test was corrected to the value at a water temperature of 15°C, and the corrected value was determined as the coefficient of permeability. As the test specimen, the maximum dry density of the sample was determined in accordance with the JIS A1210:2009 method for testing the compaction of soil by ramming, and the specimen compacted to 90% of the obtained maximum dry density was used.

[0046] <Apparent density> The apparent density was calculated by putting the filling material filled to the brim in a 100 cc stainless steel container and measuring the mass.

[0047] <Confirmation of pore size> The confirmation of pores in the nanometer order and micrometer order of the porous ceramics was carried out by observing with an electron microscope (SEMEDX Type H, manufactured by Hitachi High-Technologies Corporation) at magnifications of 100 to 10,000 times.

[0048] <Waterproofness test> One side of the side wall of a water tank with a long side of 60 cm and a short side of 30 cm was cut off, and a device was made from which water flows out from the cut part. Subsequently, a test soil bag was placed on the cut side wall part, 15 L of water was poured into the water tank, and the time until the amount of water leaking from the water tank reached 1 L was measured to evaluate the waterproofness.

[0049] <Shape followability> Six soil bags were completely immersed in water, lifted out of the water after 5 minutes, and the shape followability when installing them in 3 pieces × 2 layers without gaps was evaluated according to the following criteria. ◎: Can be installed without problems ○: Can be installed by deforming with force by hand or foot ×: The filling material hardens and it is difficult to install without gaps

[0050] (Example 1) 45.0% by mass of a foaming agent, 22.5% by mass of clay, 10.0% by mass of organic sludge, and 22.5% by mass of diatomaceous earth were mixed to obtain a plastic mixture. Next, the obtained mixture was extruded into a cylindrical shape with a diameter of 1.5 cm using a vacuum kneading and forming machine and cut into lengths of 3 cm to obtain cylindrical formed bodies.

[0051] The obtained formed bodies were fired using a continuous sintering furnace under firing conditions of a firing temperature of 990 °C and a residence time at the firing temperature of 10 minutes. After firing, the obtained porous ceramic mass was crushed using a hammer mill until the maximum particle size became 10 mm or less. Next, using a sieve, it was sieved into those with a particle size of 75 μm or less (small), those with a particle size exceeding 75 μm and 1000 μm or less (medium), and those exceeding 1000 μm (large) to obtain granular materials of ceramics classified by particle size.

[0052] Among the obtained granular materials of ceramics, 43% by mass of those with a particle size of 75 μm or less (small) and 57% by mass of those with a particle size exceeding 75 μm and 1000 μm or less (medium) were mixed to obtain a filler. The permeability coefficient of the obtained filler was 3.2×10 -7 cm / s, and the apparent density was 0.89 g / cm 3 . When the porous ceramics with a particle size of 75 μm or less (small) were observed using an electron microscope, it was confirmed that the porous ceramics had pores in the nanometer order with a pore diameter exceeding 10 nm and 1000 nm or less, and pores in the micrometer order with a pore diameter exceeding 1 μm and 70 μm or less.

[0053] The obtained filler was filled into a bag made by sewing a cotton fabric into a bag shape with dimensions of approximately 10 cm × 20 cm × 90 cm to obtain a sandbag.

[0054] The obtained sandbag was lightweight and had excellent shape followability. Also, the result of the water stop test was 1149 seconds. Furthermore, the mass of the sandbag after the water stop test was 15.4 kg, which was a sufficient weight to withstand water pressure, and no lumps were generated in the bag, maintaining its shape followability.

[0055] (Comparative Example 1) As a filler generally used for sandbags, a filler obtained by mixing gravel and mountain sand in the same mass was obtained. The particle size of the filler by sieving classification was 45% by mass for those 75 μm or less (small), 34% by mass for those over 75 μm and 1000 μm or less (medium), and 21% by mass for those over 1000 μm (large). Also, the permeability coefficient was 1.1×10 -4 cm / s, and the apparent density was 1.71 g / cm 3 .

[0056] The obtained filler was filled into a bag in which a cotton fabric was sewn into a bag shape with dimensions of about 10 cm × 20 cm × 90 cm to obtain a sandbag of about 11 L (about 19 kg).

[0057] The obtained sandbag was heavy and had poor shape followability, so it took time to install it in the test water tank without any gaps through which water would leak. Also, the result of the water stoppage test was 180 seconds, which was inferior in water stoppage compared to the sandbag of the example. Furthermore, the filler hardened in the wet bag, and the shape followability was further impaired by getting wet.

[0058] (Examples 2 to 6, Comparative Examples 2 to 5) The porous ceramics used in Example 1 and Comparative Example 1 and the filler sieved from the mixture of gravel and mountain sand were filled into the same bags used in Example 1 and Comparative Example 1 to obtain sandbags. The mixing ratios and evaluation results are shown in Table 1.

[0059] [Table 1]

[0060] From the results shown in Table 1, the sandbags according to Examples 1 to 6 had a small permeability coefficient, excellent water stoppage, a small apparent density, were lightweight, and also had excellent shape followability. On the other hand, for the sandbags according to Comparative Examples 1 to 5, sufficient performance could not be obtained for at least one of the permeability coefficient, apparent density, water stoppage, and shape followability. Considering the results according to Examples 1 to 6 and Comparative Examples 1 to 5 in more detail, it is as follows.

[0061] (Regarding the water stop test results) From the comparison between Example 2 and Comparative Example 2, in order to ensure the ability to stop water as a sandbag (water stop test results), the proportion of porous ceramics (small) with a particle size of 75 μm or less needs to be 30% by mass or more.

[0062] (Regarding shape followability) From the comparison between Example 1 and Comparative Example 4, when using non-porous crushed debris (small) instead of porous ceramics (small), the shape followability deteriorates. Also, from the comparison between Examples 3 to 6 and Comparative Example 3, in order to ensure excellent shape followability, the proportion of porous ceramics (small) needs to be 80% by mass or less. Furthermore, from the comparison of Examples 3 to 6, by setting the proportion of porous ceramics (small) to 20% by mass or more and 80% by mass or less, and setting the proportion of crushed debris (medium) with a particle size of 75 to 1000 μm, especially porous ceramics (medium), to 20% or more, the shape followability is further enhanced.

[0063] (Regarding apparent density) From the comparison between Examples 1 to 6 and Comparative Example 1, by using porous ceramics as the crushed debris, the density becomes smaller and a light sandbag can be made. In particular, from the comparison of Examples 3 to 6, by using porous ceramics (medium) as the crushed debris (medium) with a particle size of 75 to 1000 μm, the density becomes even smaller and an even lighter sandbag can be made. Also, even if porous ceramics (medium) are used as the crushed debris (medium), it does not affect the water stop performance much.

[0064] In addition, in the above examples, the case of using a mixture of clay, organic sludge, foaming agent, and diatomaceous earth as the raw material of the porous ceramics was exemplified, but the technology of the present disclosure is not limited thereto. As long as porous ceramics can be obtained, other raw materials may be used. However, according to the findings of the present inventors, when using a mixture containing at least clay and organic sludge as the raw material of the porous ceramics, porous ceramics having pores in the nanometer order with a pore diameter of more than 10 nm and 1000 nm or less and pores in the micrometer order with a pore diameter of more than 1 μm and 70 μm or less are easily obtained. [Industrial Applicability]

[0065] The sandbag of one embodiment of the present invention contains porous ceramics with small particle size, and the content of the ceramics is within a specified range, so that the sandbags are lightweight, have excellent shape conformability, and do not easily form lumps even when they absorb moisture, making it easy to line up or stack the sandbags without gaps. In addition, the sandbags can be disposed of by simply scattering the filler on the ground surface, and are easy to handle because they do not easily deteriorate even when stored for a long period of time.

Claims

1. A sandbag, wherein a filler comprising (A) 35% by mass or more and 70% by mass or less of porous ceramics having a particle size of 75 μm or less by sieving classification and (B) crushed debris having a particle size exceeding 75 μm by sieving classification is filled in a water-permeable bag.

2. The sandbag according to claim 1, wherein the (B) crushed debris contains (B') crushed debris having a particle size exceeding 75 μm and not exceeding 1000 μm by sieving classification, and the (B') crushed debris is contained in an amount of 20% by mass or more based on the total filler. The sandbag according to claim 1.

3. The sandbag according to claim 1 or 2, wherein the (B) crushed debris contains porous ceramics. The sandbag according to claim 1 or claim 2.

4. The sandbag according to any one of claims 1 to 3, wherein the porous ceramics having a particle size of 75 μm or less by sieving classification in (A) have pores in the nanometer order with a pore diameter exceeding 10 nm and not exceeding 1000 nm and pores in the micrometer order with a pore diameter exceeding 1 μm and not exceeding 70 μm. The sandbag according to any one of claims 1 to 3.

5. The permeability coefficient of the filler, measured according to the variable water level permeability test described in JIS A1218:2009, is 1.0×10 －５ cm / s or less, characterized by The sandbag according to any one of claims 1 to 4.

6. The sandbag according to any one of claims 1 to 5, wherein the bag is a fabric of natural fiber or fiber having biodegradability. The sandbag according to any one of claims 1 to 5.

7. Firing a mixture containing clay and organic sludge to obtain (A) porous ceramics having a particle size of 75 μm or less by sieving classification; obtaining a filler comprising (A) 35% by mass or more and 70% by mass or less of porous ceramics having a particle size of 75 μm or less by sieving classification and (B) crushed debris having a particle size exceeding 75 μm by sieving classification; and filling the filler into a water-permeable bag, A method for manufacturing a sandbag, comprising the above steps.

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