Weed prevention structure

Abstract

To provide a weed prevention structure that can be mass-produced at low material and manufacturing costs while realizing long-term weed-preventing effect.SOLUTION: In a weed prevention structure that consists of a weed prevention layer 1 with a specified thickness laid on the surface of a plant culture medium 4, the weed prevention layer 1 is a mixture 3 of concrete rubble powder 2 of a specific particle size including crushed and pulverized concrete rubble, the particle size accumulation curve of the mixture 3 is as such that the amount of particles with a particle size of 0.075 mm passing through is 1.5% or more and 10% or less, the amount of particles with a particle size of 0.425 mm passing through is 10% or more and 30% or less, the amount of particles with a particle size of 2.36 mm passing through is 20% or more and 55% or less, the amount of particles with a particle size of 4.75 mm passing through is 28% or more and 65% or less, the amount of particles with a particle size of 13.2 mm passing through is 55% or more and 85% or less, the amount of particles with a particle size of 19 mm passing through is 70% or more and 95% or less, and the amount of particles with a particle size of 26.5 mm passing through is 90% or more and 100% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a weed prevention structure for preventing the proliferation of weeds in plant medians along both sides of roads, in median strips of roads, or in parks and the like. [Background technology]

[0002] The present inventor has developed a paving stone that is laid on a plant culture medium to prevent the proliferation of weeds (Patent Document 1). This paving stone is made by firing calcium-containing stones, which transfers the calcium contained inside to the surface, effectively preventing the proliferation of weeds for a long period of time, and has the advantage that it can be laid on the surface of the culture medium to effectively prevent the proliferation of weeds.

[0003] The paving stones described in Patent Document 1, which was previously developed by the present inventor, are manufactured by the following method and laid to cover the surface of the medium. The paving stones are manufactured by mixing igneous rock powder generated in the process of crushing igneous rock containing calcium with powder residue generated when natural stone is crushed and crushed stone is separated in the process of artificially manufacturing crushed stone used for concrete aggregate, forming the mixture into porous granular material with an igneous rock powder content of 70 to 80% by weight, and firing the formed raw material granules to transfer calcium to the surface. When the surface of the medium is covered with the above paving stones, water that adheres to the surface due to rainwater or watering becomes strongly alkaline, preventing weed seeds from germinating. The water that adheres to the surface of the paving stones becomes strongly alkaline due to the calcium that has been fired and migrated to the surface. The calcium is fired and migrates to the surface of the paving stones to prevent the proliferation of weeds. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3806122 Summary of the Invention [Problem to be solved by the invention]

[0005] The paving stones described in Patent Document 1 can prevent the proliferation of weeds for a long period of time, but have the drawback of being laborious and expensive to manufacture. This is because they are manufactured by mixing igneous rock powder with powdered residue of natural stone generated during the aggregate manufacturing process, forming the mixture into porous granules, and then firing the formed raw material granules.

[0006] The present invention was developed with the further objective of eliminating the above-mentioned drawbacks, and one of the objects of the present invention is to provide a weed prevention structure that has an extremely economical effect, which achieves a weed prevention effect that is equal to or better than the paving stones of Patent Document 1, while reducing both raw material costs and manufacturing costs, allowing for inexpensive mass production, and which can be laid on a culture medium to prevent the proliferation of weeds for a long period of time. [Means for solving the problem]

[0007] A weed prevention structure according to one embodiment of the present disclosure is a weed prevention structure comprising a weed prevention layer of a predetermined thickness laid on the surface of a plant culture medium, the weed prevention layer being a mixture of concrete rubble powder of a specific particle size including crushed and pulverized concrete rubble, and the particle size accumulation curve of the mixture is such that the amount of particles passing through is 0.075 mm in diameter is 1.5% or more and 10% or less, the amount of particles passing through is 0.425 mm in diameter is 10% or more and 30% or less, the amount of particles passing through is 20% or more and 55% or less, the amount of particles passing through is 4.75 mm in diameter is 28% or more and 65% or less, the amount of particles passing through is 55% or more and 85% or less, the amount of particles passing through is 19 mm in diameter is 70% or more and 95% or less, and the amount of particles passing through is 26.5 mm in diameter is 90% or more and 100% or less. Effect of the Invention

[0008] The above weed prevention structure realizes a weed prevention effect that is comparable to that of the paving stones described in Patent Document 1, which was previously developed by the present invention, while reducing both the raw material cost and the manufacturing cost, allowing for inexpensive mass production, and furthermore, by laying it on the culture medium, it realizes an extremely high economic effect by preventing the proliferation of weeds for a long period of time.In addition, the above weed prevention structure also realizes the feature that it is convenient to plant new plants in the culture medium and to replant plants, since the powdered granular material laid on the culture medium can be easily removed to expose the surface of the culture medium. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of a weed prevention structure according to an embodiment of the present disclosure. [Diagram 2] 1 is a graph showing a particle size accumulation curve of a mixture of kongara powder and granular material according to an embodiment of the present disclosure. [Diagram 3] 1 is a photograph of a transparent case in which a mixture of corn pulp and granules according to an embodiment of the present disclosure is stored and classified by particle size. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper", "lower", and other terms including these terms) are used as necessary, but the use of these terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the meanings of these terms do not limit the technical scope of the present invention. In addition, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members. Furthermore, the embodiments shown below are specific examples of the technical ideas of the present invention, and do not limit the present invention to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative and not to limit the scope of the present invention. Furthermore, the contents described in one embodiment or example can be applied to other embodiments or examples. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation.

[0011] The weed prevention structure according to one embodiment of the present invention is a weed prevention structure comprising a weed prevention layer laid on the surface of a plant culture medium. The weed prevention layer is a mixture of concrete debris powder having a specific particle size, including crushed and pulverized concrete debris. The particle size accumulation curve of the mixture is as follows: The amount of particles with a particle size of 0.075 mm passing through the facility is 1.5% or more and 10% or less. The amount of particles with a particle size of 0.425 mm passing through the facility is 10% or more and 30% or less. The amount of particles with a particle size of 2.36 mm passing through the facility is 20% or more and 55% or less. The amount of particles with a particle size of 4.75 mm passing through the facility is 28% or more and 65% or less. The passing amount of particles with a particle size of 13.2 mm is 55% or more and 85% or less. The passing amount of particles with a particle size of 19.0 mm is 70% or more and 95% or less. The passing amount of particles with a particle size of 26.5 mm shall be 90% or more and 100% or less.

[0012] The above weed prevention structure has the advantage of being able to reduce raw material costs by effectively reusing concrete debris, and is also able to reduce manufacturing costs by manufacturing it through a simple process of crushing, pulverizing, separating by particle size, and mixing the concrete debris, allowing it to be mass-produced at low cost. In addition, the above weed prevention structure achieves a weed proliferation prevention effect that is comparable to that of the paving stones described in Patent Document 1, which the inventor previously developed, by laying a mixture of powdered concrete debris on the plant culture medium. Furthermore, the above weed prevention structure also achieves the advantage of being convenient for planting new plants in the culture medium and for replanting plants, since the powdered concrete debris laid on the culture medium can be easily removed to expose the surface of the culture medium.

[0013] The above weed prevention structure is extremely effective in preventing the proliferation of weeds because the kongara powder and granules are selected by particle size and mixed with the selected kongara powder and granules of a specific particle size in a specific ratio. When a mixture of kongara powder and granules of a specific particle size in a specific mixing ratio is laid on the surface of the medium, kongara powder and granules of smaller particle size penetrate into the gaps that are created between the larger kongara powder and granules, blocking the transmission of light, and the calcium contained in the larger kongara powder and granules migrates to the surface over time, making water such as rainwater alkaline, creating external conditions that are unfavorable for the growth of weeds. In particular, the above weed prevention structure contains ultrafine kongara powder with a particle size of 0.075 mm or less and fine kongara powder with a particle size of 0.075 to 0.425 mm, as shown in the photograph of Figure 3, so that the gaps between the large-sized kongara powder and granules are filled with kongara powder smaller than the gaps, such as ultrafine and fine kongara powder and granules, without any gaps. In addition to the large-sized kongara powder and granules, the ultrafine and fine kongara powder and granules filled in the gaps between the large-sized kongara powder and granules alkalize the moisture absorbed over a long period of time, making the external conditions of the plant unfavorable for growth, thereby preventing the proliferation of weeds. Furthermore, the mixture of kongara powder and granules also contains large-sized kongara powder and granules, and the large-sized kongara powder and granules migrate calcium to the surface over a long period of time, making the moisture absorbed by the fine kongara powder and granules filling the gaps alkaline, thereby preventing the proliferation of weeds.

[0014] Concrete debris is waste generated by demolishing buildings and other structures. Concrete structures are made alkaline inside to prevent rusting of the buried iron materials such as rebars and steel frames. When the pH of a concrete structure drops to around 10 over time and becomes neutralized, the buried iron materials rust and lose strength. To prevent the strength loss caused by rusting of the iron materials, concrete structures are prevented from neutralizing inside by methods such as re-alkalization and cross-section repair methods. Concrete debris powder, which is the crushed concrete structure material that prevents internal neutralization, has an alkaline pH value of 10 or less. A weed prevention layer, which is a mixture of concrete debris powder with an alkaline pH value of 10 or less that is laid on the surface of a medium, prevents the proliferation of weeds by creating an environment in which the external conditions of plants are inhibited from proliferation.

[0015] In the above weed prevention structure, the weed prevention layer that covers the surface of the medium is a mixture containing large granular kongara powder with a particle size of 26.5 to 19 mm, as shown in the photograph in Figure 3. The large granular kongara powder transfers the calcium inside to the surface over a long period of time, maintaining the surface alkaline. The granular kongara powder with an alkaline surface keeps the weed prevention layer alkaline, maintaining the external conditions for plants that inhibit reproduction.

[0016] In the above weed prevention structure, the weed prevention layer covering the surface of the culture medium not only blocks light, but also remains alkaline for a long period of time, thereby creating an environment outside the plants that inhibits their growth, effectively preventing the growth of weeds.

[0017] In another embodiment of the weed prevention structure of the present invention, the particle size accumulation curve of the mixture can be characterized as follows: The amount of particles with a particle size of 0.075 mm passing through the facility is 1.5% or more and 5% or less. The amount of particles with a particle size of 0.425 mm passing through the facility is between 10% and 20%. The amount of particles with a particle size of 2.36 mm passing through the facility is 25% or more and 40% or less. The amount of particles with a particle size of 4.75 mm passing through the facility is 35% or more and 55% or less. The passing amount of particles with a particle size of 13.2 mm is 65% or more and 85% or less. The passing amount of particles with a particle size of 19.0 mm is 80% or more and 90% or less. The passing amount of particles with a particle size of 26.5 mm is 95% or more and 100% or less.

[0018] In another embodiment of the weed prevention structure of the present invention, the particle size of the 10% passing amount of the mixture on the particle size accumulation curve can be set to 0.075 mm or more and 0.425 mm or less. The above weed prevention structure has a feature that the particle size of the mixture constituting the weed prevention layer is small, at 0.075 mm or more and 0.425 mm or less, in other words, contains a relatively large amount of fine kongara powder and granules, so that the gaps between the large particle size kongara powder and granules are blocked by a large amount of fine kongara powder and granules, reliably blocking the transmission of light and more effectively preventing the proliferation of weeds.

[0019] In another embodiment of the weed prevention structure of the present invention, the particle size accumulation curve of the mixture can be set so that the particle size of the 10% passing amount is 0.075 mm or more and 0.425 mm or less, and the particle size of the 60% passing amount is 3 mm or more and 15 mm or less. The above weed prevention structure has the particle size of the mixture constituting the weed prevention layer being 0.075 mm or more and 0.425 mm or less, and the particle size of the 60% passing amount being 3 mm or more and 15 mm or less, and the gaps between the large-sized kongara powder and granules are blocked with kongara powder and granules having a particle size of 3 to 15 mm, and the gaps between the kongara powder and granules are further blocked with fine kongara powder and granules having a particle size of 3 mm or less, and even 0.425 mm or less, so that it has the characteristic of being able to reliably block the transmission of light and more effectively prevent the proliferation of weeds.

[0020] The weed prevention structure according to another embodiment of the present invention can contain large kongara powdered granules having a particle size of 26.5 mm or more, with the maximum particle size of the mixture of kongara powdered granules being 26.5 to 31.5 mm. The weed prevention structure described above has a large particle size of kongara powdered granules having a maximum particle size of 26.5 to 31.5 mm, so that the large particle size kongara powdered granules transfer calcium to the surface over a long period of time, and has the characteristic of being able to effectively prevent the proliferation of weeds on the surface of the medium over a long period of time.

[0021] In the weed prevention structure according to another embodiment of the present invention, the uniformity coefficient of the mixture of kongara powder and granular materials can be set to 25 to 50. The above weed prevention structure specifies a state in which the mixture contains kongara powder and granular materials of a wide range of particle sizes by setting the uniformity coefficient calculated using "particle size of 60% passing amount / particle size of 10% passing amount" to 25 to 50, or approximately 35, so that the large powder and granular materials maintain alkalinity by transferring calcium to the surface for a long period of time, and the fine powder and granular materials effectively block the gaps between the large powder and granular materials to prevent light from passing through, thereby realizing the characteristic of effectively preventing the proliferation of weeds.

[0022] In the weed prevention structure according to another embodiment of the present invention, the uniformity coefficient of the mixture of kongara powder and granular materials can be set to 30 to 40. The above weed prevention structure specifies a state in which the mixture contains kongara powder and granular materials of a wide range of particle sizes by setting the uniformity coefficient calculated using "particle size of 60% passing amount / particle size of 10% passing amount" to 30 to 40, or approximately 35, so that the large powder and granular materials retain alkalinity by transferring calcium to the surface for a long period of time, and the fine powder and granular materials effectively block the gaps between the large powder and granular materials to prevent light from passing through, thereby realizing the characteristic of effectively preventing the proliferation of weeds.

[0023] In the weed prevention structure according to another embodiment of the present invention, the thickness of the weed prevention layer can be 5 cm or more, or 10 cm or more. By laying a weed prevention layer of a specified thickness on the surface of the plant culture medium, the above weed prevention structure blocks light transmission, and the calcium contained in the kongara powder and granular material migrates to the surface over time, making moisture such as rainwater alkaline, creating external conditions that are unfavorable for the growth of weeds, thereby achieving the characteristic of effectively preventing the proliferation of weeds. (Embodiment 1)

[0024] The weed prevention structure shown in the cross-sectional view of Figure 1 prevents the proliferation of weeds by laying a weed prevention layer 1 on the surface of a medium 4 (ground). The weed prevention layer 1 contains a mixture 3 of concrete rubble granules 2 of a specific particle size. The concrete rubble granules 2 are produced by effectively utilizing the waste material called "congara" (concrete rubble), which is industrial waste generated by demolishing buildings and other structures, as a raw material, and therefore the raw material cost can be significantly reduced. The concrete rubble granules 2 are produced by crushing and grinding the concrete rubble, sorting it into a specific particle size using a sieve with a specific nominal size, and mixing the selected concrete rubble granules 2 of a specific particle size in a specific ratio. Therefore, while it can be effectively used as an excellent weed proliferation prevention material, it has the characteristic of being able to be mass-produced at low cost, with both raw material costs and manufacturing costs being extremely low.

[0025] It is laid on the surface of the culture medium 4 (ground). The thickness (d) of the weed prevention layer 1 is, for example, 3 cm or more, preferably 5 cm or more, and more preferably 10 cm or more. The thicker the weed prevention layer 1, the greater the effect of preventing weed proliferation and the longer the period during which weed proliferation can be prevented. Therefore, the thickness of the weed prevention layer 1 is set to an optimal thickness taking into consideration the required weed prevention effect and the period during which weed proliferation is prevented. For example, a thickness of 5 cm for the weed prevention layer 1 can prevent weed proliferation for three years or more, and a thickness of 10 cm for the weed prevention layer 1 can prevent weed proliferation for a long period of five years or more. Therefore, the film thickness of the weed prevention layer 1 is adjusted to an optimal value taking into consideration the period during which weed proliferation is prevented.

[0026] The mixture 3 of concrete husk powder 2 for the weed prevention layer 1 can be produced by sorting concrete husk powder 2, such as aggregate obtained by crushing concrete rubble, into specific particle sizes with a sieve, and then mixing the sorted concrete husk powder 2 of the specific particle size in a specific ratio.

[0027] The photograph in FIG. 3 shows a mixture 3 of corn husk powder 2 separated by particle size and placed in a transparent case. This mixture 3 of corn husk powder 2 can be manufactured, for example, by the following process. (1) Concrete debris is crushed and pulverized to produce concrete debris 2. Concrete debris 2 is a mixture of powder particles of various particle sizes. (2) The corn flakes 2 are sorted by particle size in sequence using multiple sieves with different mesh openings.

[0028] To separate particles of a particular size, for example, sieves with the following mesh sizes are used in sequence: The first sieve has a mesh size of 26.5 mm. A second sieve with a mesh size of 19 mm, A third sieve with a mesh size of 13.2 mm. A fourth sieve with a mesh size of 4.75 mm; The fifth sieve has a mesh size of 2.36 mm. A sixth sieve with a mesh size of 0.425 mm; A seventh sieve with a mesh size of 0.075 mm is used in turn to separate the kongara powder 2 according to particle size.

[0029] In the sorting process, sieves with gradually smaller mesh openings are used in order from the largest sieve to sort into specific particle sizes in the following order (1) to (7). (1) The corn pulp and granules 2 that pass through the first sieve but do not pass through the second sieve are selected as corn pulp and granules 2 having a particle size of 26.5 mm to 19 mm. (2) The corn pulp and granules 2 that pass through the second sieve but do not pass through the third sieve are selected as corn pulp and granules 2 having a particle size of 19.0 mm to 13.2 mm. (3) The corn husk powder and granular material 2 that passes through the third sieve but does not pass through the fourth sieve is selected as corn husk powder and granular material 2 having a particle size of 13.2 mm to 4.75 mm. (4) The corn pulp and granules 2 that pass through the fourth sieve but do not pass through the fifth sieve are selected as corn pulp and granules 2 having a particle size of 4.75 mm to 2.36 mm. (5) The corn pulp and granules 2 that pass through the fifth sieve but do not pass through the sixth sieve are selected as corn pulp and granules 2 having a particle size of 2.36 mm to 0.425 mm. (6) The corn pulverized material 2 that passes through the sixth sieve but does not pass through the seventh sieve is selected as corn pulverized material 2 having a particle size of 0.425 mm to 0.075 mm. (7) The corn husk powder 2 that passed through the seventh sieve is selected as corn husk powder 2 having a particle size of 0.75 mm or less. EXAMPLES

[0030] The mixing ratio of kongara powder 2 of the selected particle size is adjusted to produce mixture 3 that has the particle size (particle size) accumulation curve shown by solid line A in Figure 2. This mixture 3 is produced by adjusting the mixing ratio of kongara powder 2 of the selected specific particle size to produce a mixture, measuring the particle size accumulation curve of mixture 3, and adjusting the mixing ratio of kongara powder 2 of different particle sizes so that the particle size accumulation curve has the characteristics shown by solid line A in Figure 2. Mixture 3 of kongara powder 2 with a particle size accumulation curve of solid line A in Figure 2 has a maximum particle size of 26.5 mm, a particle size at 60% passing volume of 8.75 mm, a particle size at 10% passing volume of 0.25 mm, and a uniformity coefficient indicating the particle size distribution corresponding to the gradient of the particle size accumulation curve of 35. EXAMPLES

[0031] Furthermore, the mixing ratio of the kongara powder 2 of the selected particle size is adjusted to obtain mixture 3 of Example 2, which has a particle size accumulation curve shown by the chain line B in Figure 2. As in Example 1, mixture 3 of Example 2 is prepared by adjusting the mixing ratio of the kongara powder 2 of the selected specific particle size to obtain mixture 3, and then the particle size accumulation curve of mixture 3 is measured to obtain the particle size accumulation curve shown by the chain line B in Figure 2. This mixture 3 of kongara powder 2 has a maximum particle size of 26.5 mm, a particle size at 60% passing volume of 6.50 mm, a particle size at 10% passing volume of 0.17 mm, and a uniformity coefficient of 38, which indicates the particle size distribution corresponding to the gradient of the particle size accumulation curve. EXAMPLES

[0032] Furthermore, the mixing ratio of the selected kongara powder 2 is adjusted to obtain mixture 3 of Example 3, which has a particle size accumulation curve shown by the chain line C in Figure 2. As in Example 1, the mixing ratio of the selected kongara powder 2 of a specific particle size is adjusted to obtain mixture 3, and then the particle size accumulation curve of mixture 3 is measured to obtain mixture 3 with the particle size accumulation curve shown by the chain line C in Figure 2. This mixture 3 of kongara powder 2 has a maximum particle size of 26.5 mm, a 60% particle size of 3.75 mm, a 10% particle size of 0.075 mm, and a uniformity coefficient of 50, which indicates the particle size distribution corresponding to the gradient of the particle size accumulation curve. It was confirmed that mixture 3 of Example 3 has a greater weed control effect than other examples based on the degree of weed proliferation. It is believed that the gaps between the larger grain size kongara powder 2 are blocked by the smaller grain size kongara powder 2, effectively preventing light from passing through, and the kongara powder 2 transfers calcium to the surface, more effectively preventing the proliferation of weeds. EXAMPLES

[0033] Furthermore, the mixing ratio of the kongara powder 2 of the selected particle size is adjusted to obtain mixture 3 of Example 4, which has the particle size accumulation curve shown by the chain line D in Figure 2. As in Example 1, mixture 3 of Example 4 is prepared by adjusting the mixing ratio of the kongara powder 2 of the selected specific particle size to obtain mixture 3, and then the particle size accumulation curve of mixture 3 is measured to obtain mixture 3 with the particle size accumulation curve shown by the chain line D in Figure 2. This mixture 3 of kongara powder 2 has a maximum particle size of 31.5 mm, a 60% particle size of 10.47 mm, a 10% particle size of 0.35 mm, and a uniformity coefficient of 30, which indicates the particle size distribution corresponding to the gradient of the particle size accumulation curve. EXAMPLES

[0034] Further, the mixing ratio of the selected kongara powder 2 is adjusted to obtain the mixture 3 of Example 5, which has a particle size accumulation curve shown by the chain line E in FIG. 2. As in Example 1, the mixture 3 of Example 5 is prepared by adjusting the mixing ratio of the selected kongara powder 2 of a specific particle size to obtain the mixture 3, and then the particle size accumulation curve of the mixture 3 is measured to obtain the mixture 3 of Example 5, which has a particle size accumulation curve shown by the chain line E in FIG. 2. The mixture 3 of this kongara powder 2 has a maximum particle size of 26.5 mm, a 60% particle size of 13.81 mm, a 10% particle size of 0.425 mm, and a uniformity coefficient of 32, which indicates the particle size distribution corresponding to the gradient of the particle size accumulation curve. It was confirmed that the weed control effect of the mixture 3 of Example 5 lasts longer than that of the other examples, based on the weed propagation results after three years. It is believed that the large-grained corn husk powder 2 transfers calcium to the surface over a long period of time, making the weed prevention layer 1 alkaline and maintaining the external conditions of the plants in an environment that inhibits their growth, thereby effectively preventing the growth of weeds over a long period of time.

[0035] For comparison, the paving stones of Comparative Example 1 are used. The paving stones of Comparative Example 1, which are laid on the surface of the medium (ground) as a weed prevention layer, are manufactured by the following process. Igneous rock powder and powder residue are mixed, molded, and fired at a firing temperature of 1000°C. The igneous rock is an extrusive rock containing the following components, which is crushed to an average particle size of about 3 to 5 mm and then pulverized to produce igneous rock powder. SiO2……70% by weight Al2O3……16% by weight Fe2O3……2% by weight CaO……2.5% by weight

[0036] The powder residue is the residue that remains when natural stone is crushed and the crushed stone is separated in the process of artificially producing crushed stone to be used as aggregate for concrete. The powder residue is mixed with igneous rock powder and formed into granules. The mixture of igneous rock powder and powder residue is 80% by weight of igneous rock powder and 20% by weight of powder residue.

[0037] Water is added to the mixed powder and it is molded into spheres with an average particle size of about 5 mm. The powder with added water is fed into a rotating trommel, and the trommel is rolled while water is sprayed on it, so that the spheres grow large like snowmen and take on the desired spherical shape. After drying the molded raw material particles, they are carried into a firing furnace and fired at 1000°C for 3 hours. Comparative Example 2

[0038] For comparison, the paving stones of Comparative Example 2 are used. The paving stones of Comparative Example 2 are crushed stones made by crushing the igneous rock used in Example 1 and not firing it.

[0039] When 100 g of the mixture 3 of granular kongara pulverized material 2 of Examples 1 to 5 and the crushed stone of Comparative Examples 1 and 2 were immersed in 1000 cc of water for 20 minutes and the pH of the water was measured, it was found that the mixture 3 of granular kongara pulverized material 2 of the Examples of the present invention exhibited strong alkalinity similar to that of the paving stone of Comparative Example 1 while reducing both the raw material cost and the manufacturing cost more than the crushed stone of Comparative Example 1. The crushed stone of Comparative Example 2, which was not fired, had the advantage of being easily manufactured, but showed a nearly neutral pH of 7.6, and it was not possible to expect any alkalinity-based effect in preventing the proliferation of weeds. The mixture 3 of granular kongara pulverized material 2 of Examples 1 to 5 exhibited a strong alkaline pH of 9.2 to 9.7. Weed proliferation can be effectively suppressed, particularly by preventing seed germination. The pH of a medium suitable for seed germination is 6 to 7.5. Mixture 3 in Examples 1 to 5 has a pH that is considerably higher than that suitable for germination, making medium 4 strongly alkaline, thereby preventing seed germination and effectively suppressing weed proliferation.

[0040] Example 1: pH 9.4 Example 2: pH 9.5 Example 3: pH 9.7 Example 4: pH 9.3 Example 5: pH 9.2 Comparative Example 1 (paving stone of Patent Document 1)…pH 9.8 Comparative Example 2 (unfired paving stones) pH 7.6

[0041] Furthermore, the mixture 3 of the kongara powder and granules 2 in Examples 1 to 5 not only makes the pH of the medium 4 strongly alkaline, but also has a uniformity coefficient in the range of 25 to 50, which corresponds to the gradient of the particle size accumulation curve, so that small-sized powder and granules penetrate into the gaps of the large-sized powder and granules, and the fine and very fine kongara powder and granules 2 penetrate into the gaps of the small-sized powder and granules, and the weed prevention layer 1 blocks the transmission of light, so that the synergistic effect of both making the medium 4 strongly alkaline and blocking sunlight is realized, which is a feature that can extremely effectively prevent the proliferation of weeds. In the mixture 3 of the kongara powder and granules 2 of a specific particle size, powder and granules smaller than the gaps repeatedly penetrate and fill the gaps of the powder and granules without leaving any gaps, improving the effect of blocking light transmission and supplying the moisture absorbed over a long period of time to the surface of the medium 4 as alkali, and effectively suppressing the proliferation of weeds.

[0042] The mixture 3 of the granular kongara powder 2 produced in Examples 1 to 5 and the paving stones of Comparative Examples 1 and 2 were actually laid on the surface of a medium 4 to a thickness of 5 cm, and the state of weed propagation was observed. In the weed prevention layer 1 made of the granular kongara powder 2 of Examples 1 to 5 and the weed prevention layer with the paving stones of Comparative Example 1 laid, no weeds propagated even after three years. In contrast, a large amount of weeds propagated in the weed prevention layer with the paving stones of Comparative Example 2 laid to a thickness of 5 cm after three years. However, the experiment was conducted in a mountainous area exposed to wind and rain, well exposed to the sun, and where weeds are likely to propagate nearby. Enclosures were provided to prevent the powder and granular material and paving stones of each Example and Comparative Example from flowing out to the surrounding area due to rainwater, wind and snow, and the observations were conducted.

[0043] As shown in the above Examples 1 to 5, the weed prevention structure realizes a weed prevention effect that is comparable to that of the paving stones (paving stones of Comparative Example 1) described in Patent Document 1, which were developed earlier by the present invention, and can be laid on a culture medium to prevent weeds from multiplying for a long period of time. This is because the paving stones of the present invention are a mixture 3 of kongara powder granules 2 in which kongara powder granules 2 of specific particle sizes are mixed at a specific ratio, and contain kongara powder granules 2 ranging from very fine, fine, small to large particle sizes, and kongara powder granules 2 of small particle sizes etc. penetrate into the gaps formed between the large particle size kongara powder granules 2, blocking the transmission of light, and the calcium contained in each kongara powder granules migrates to the surface over time, making water such as rainwater alkaline and creating external conditions that are unfavorable for the growth of weeds. The calcium contained in the kongara powder granules migrates to the surface over a long period of time at the same or different times depending on the particle size and surface area of ​​each powder granule, thereby preventing weeds from multiplying for a long period of time. The large-grain concrete granules 2 transfer calcium to the surface over a long period of time, and the fine concrete granules 2 filling the gaps absorb the moisture, turning it alkaline, preventing the proliferation and germination of weeds. Furthermore, the weed prevention structure reduces both raw material costs and manufacturing costs, allowing for inexpensive mass production. This is because concrete debris itself is waste generated when buildings and other structures are demolished, and by effectively reusing the concrete debris, raw material costs can be reduced, and furthermore, the mixture 3 of concrete granules 2 is produced through a simple process of crushing, pulverizing, separating by particle size, and mixing the concrete debris, reducing manufacturing costs and allowing for inexpensive mass production. [Industrial Applicability]

[0044] The above weed prevention structure achieves a weed prevention effect that is equal to or better than the paving stones (paving stones of Comparative Example 1) described in Patent Document 1, which were previously developed by the present invention, while reducing both raw material and manufacturing costs, allowing it to be mass-produced at low cost, and it can be used as a weed prevention structure that achieves great economic benefits by being laid on a culture medium to prevent the proliferation of weeds over a long period of time. [Explanation of symbols]

[0045] 1…Weed prevention layer 2. Corn husk powder 3...Mixture 4. Culture medium

Claims

1. A weed prevention structure comprising a weed prevention layer of a predetermined thickness laid on the surface of a plant culture medium, The weed prevention layer is A mixture of concrete debris powder of a specific particle size, including crushed and pulverized concrete debris. The particle size accumulation curve of the mixture is The amount of particles passing through the filter with a particle size of 0.075 mm is 1.5% or more and 10% or less. The amount of particles passing through the filter with a particle size of 0.425 mm is 10% or more and 30% or less. The amount of particles passing through the filter with a particle size of 2.36 mm is 20% or more and 55% or less. The amount of particles passing through the filter with a particle size of 4.75 mm is 28% or more and 65% or less. The amount of particles passing through the filter with a particle size of 13.2 mm is 55% or more and 85% or less. The passing amount of particles with a particle size of 19.0 mm is 70% or more and 95% or less. A weed prevention structure that limits the amount of weeds with a particle size of 26.5 mm to passing through to 90% or more and 100% or less.

2. 2. The weed prevention structure according to claim 1, The particle size accumulation curve of the mixture is The amount of particles having a particle size of 0.075 mm passing through the filter is 1.5% or more and 5% or less. The amount of particles passing through the filter with a particle size of 0.425 mm is 10% or more and 20% or less. The amount of particles passing through the filter with a particle size of 2.36 mm is 25% or more and 40% or less. The amount of particles passing through the filter with a particle size of 4.75 mm is 35% or more and 55% or less. The passing amount of particles with a particle size of 13.2 mm is 65% or more and 85% or less. The passing amount of particles with a particle size of 19.0 mm is 80% or more and 90% or less. A weed prevention structure that limits the amount of weeds with a particle size of 26.5 mm to passing through to 95% or more and 100% or less.

3. 2. The weed prevention structure according to claim 1, The particle size accumulation curve of the mixture is A weed prevention structure in which the particle size of 10% passing through is 0.075 mm or more and 0.425 mm or less.

4. The weed prevention structure according to claim 3, The particle size accumulation curve of the mixture is The particle size of the 10% passing amount is set to 0.075 mm or more and 0.425 mm or less, A weed prevention structure in which the particle size of 60% of the weeds passing through is set to be 3 mm or more and 15 mm or less.

5. 2. The weed prevention structure according to claim 1, The weed prevention structure comprises a mixture containing large corn husk powder having a maximum particle size of 26.5 to 31.5 mm.

6. A weed prevention structure according to any one of claims 1 to 5, A weed prevention structure in which the uniformity coefficient of the mixture of corn flakes and powdered granules is 25 to 50.

7. 2. The weed prevention structure according to claim 1, A weed prevention structure, wherein the thickness of the weed prevention layer is 5 cm or more.

8. 8. The weed prevention structure according to claim 7, A weed prevention structure, wherein the thickness of the weed prevention layer is 10 cm or more.

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