Method for manufacturing construction material, and ground solidification method

Abstract

To provide a method for manufacturing a construction material which has improved strength and is biodegradable, and a ground solidification method.SOLUTION: A method for manufacturing a construction material includes: powdering a pellet of a biodegradable plastic P (S1); filtering the powdered biodegradable plastic through a filter having a predetermined mesh value (S2); producing a biodegradable plastic mixed soil obtained by mixing mixed object soil and the filtered biodegradable plastic (S3); heating the biodegradable plastic mixed soil at a temperature which is equal to or higher than a temperature at which the biodegradable plastic melts and is not thermally decomposed, for a predetermined time according to the mesh value of the filter (S5); and cooling the heated biodegradable plastic mixed soil to a glass transition point of the biodegradable plastic or less, and solidifying the biodegradable plastic mixed soil (S6).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing a biodegradable construction material and a method for soil solidification. [Background technology]

[0002] In recent years, biodegradable materials have been attracting attention as a way to reduce the burden on the environment, and research is being conducted into the application of biodegradable materials in the field of construction. For example, Patent Document 1 discloses a biodegradable ground improvement material in which a biodegradable polymer such as polyvinyl alcohol and a hardener for the biodegradable polymer are injected into the target ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-47337 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above technique, since liquid polyvinyl alcohol is injected together with a hardener, there is a problem in that it is difficult to obtain sufficient strength as a foundation.

[0005] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a method for manufacturing biodegradable construction materials having improved strength. [Means for solving the problem]

[0006] In order to solve the above problem, the invention described in claim 1 is characterized by including a powdering step of powdering biodegradable plastic pellets, a filtering step of filtering the powdered biodegradable plastic with a filter of a predetermined mesh value, a mixing step of generating biodegradable plastic mixed soil by mixing the soil to be mixed with the filtered biodegradable plastic, a heating step of heating the biodegradable plastic mixed soil at a temperature above the melting temperature of the biodegradable plastic but at which the biodegradable plastic does not thermally decompose for a predetermined time according to the mesh value of the filter, and a solidification step of cooling the heated biodegradable plastic mixed soil to a temperature below the glass transition point of the biodegradable plastic and solidifying it.

[0007] The invention described in claim 2 is a construction material manufacturing method described in claim 1, characterized in that the filtering step filters the powdered biodegradable plastic using two types of filters having different mesh values ​​so that the particle size falls within a predetermined range.

[0008] The invention described in claim 3 is characterized in that in the construction material manufacturing method described in claim 1 or 2, the proportion of the biodegradable plastic is less than that of the soil to be mixed.

[0009] The invention described in claim 4 is characterized in that in the construction material manufacturing method described in claim 1 or 2, the biodegradable plastic is polylactic acid.

[0010] The invention described in claim 5 is characterized in that in the method for producing a construction material described in claim 1 or 2, the biodegradable plastic is a polymer made from natural products.

[0011] The invention described in claim 6 is characterized by including a powdering step of powdering biodegradable plastic pellets, a filtering step of filtering the powdered biodegradable plastic with a filter of a predetermined mesh value, a laying step of mixing the soil to be mixed with the filtered biodegradable plastic and laying the biodegradable plastic mixed soil on the ground, a heating step of heating the laid biodegradable plastic mixed soil at a temperature above the melting temperature of the biodegradable plastic but not at which the biodegradable plastic decomposes thermally for a predetermined time according to the mesh value of the filter, and a solidification step of cooling the heated biodegradable plastic mixed soil to a temperature below the glass transition point of the biodegradable plastic and solidifying it.

[0012] In addition, the invention described in claim 7 is characterized in that, in the ground solidification method described in claim 6, it further includes a compression step of compressing the biodegradable plastic mixed soil by vibration after the biodegradable plastic mixed soil has been laid. Effect of the Invention

[0013] According to the present invention, biodegradable plastic pellets are powdered, the powdered biodegradable plastic is filtered with a filter of a predetermined mesh value, the soil to be mixed and the filtered biodegradable plastic are mixed to produce biodegradable plastic mixed soil, the biodegradable plastic mixed soil is heated at a temperature above the melting temperature of the biodegradable plastic but not at which the biodegradable plastic decomposes thermally for a predetermined period of time according to the mesh value of the filter, and the heated biodegradable plastic mixed soil is cooled to below the glass transition point of the biodegradable plastic to solidify it, thereby making it possible to produce construction materials with improved strength. [Brief description of the drawings]

[0014] [Figure 1] 1 is a block diagram showing a schematic diagram of a construction material manufacturing system according to an embodiment of the present invention. [Diagram 2] 4 is a flowchart showing an example of an operation of manufacturing construction materials according to the embodiment. [Diagram 3]1 is a graph showing an example of particle size of a biodegradable plastic according to an embodiment. [Figure 4] 1 is a graph showing an example of the relationship between the strength of a construction material according to an embodiment and the particle size of a biodegradable plastic. [Diagram 5] 1 is a graph showing an example of the relationship between the strength of a construction material and the proportion of biodegradable plastics according to an embodiment. [Figure 6] 1 is a graph showing an example of the relationship between the density of a construction material and the proportion of biodegradable plastic in an embodiment. [Figure 7] 1 is a graph showing an example of the relationship between strength and heating time of a construction material according to an embodiment. [Figure 8] FIG. 2 is a schematic diagram showing an example of an enlarged view of solidified soil of a construction material according to the embodiment. [Figure 9] FIG. 1 is a schematic diagram showing an example of a construction example to which a construction material according to an embodiment is applied. [Figure 10] FIG. 1 is a schematic diagram showing an example of a construction example to which a construction material according to an embodiment is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an embodiment in which the present invention is applied to construction materials and the like.

[0016] [1. Overview of the configuration and functions of the construction material manufacturing system]

[0017] First, the configuration and general functions of a construction material manufacturing system according to one embodiment of the present invention will be described with reference to FIG.

[0018] FIG. 1 is a block diagram showing a schematic diagram of a construction material manufacturing system according to the present embodiment.

[0019] As shown in Figure 1, the construction material manufacturing system 10 of this embodiment includes a crusher 11 that crushes biodegradable plastic pellets, a sieve 12 that filters biodegradable plastics of a predetermined particle size range, a mixer 13 that mixes powdered biodegradable plastics with soil to be mixed, such as sand or soil from a construction site, to create biodegradable plastic mixed soil, and a heater 14 that heats the biodegradable plastic mixed soil.

[0020] Here, examples of biodegradable plastics include chemically synthesized polymers such as polylactic acid, polycaprolactone, polybutylene succinate, etc. Examples of biodegradable plastics include microbially produced polymers such as polyester, cellulose, polyamino acids, etc. Examples of biodegradable plastics include natural (plant and animal) polymers such as cellulose, starch, chitin, chitosan, collagen, etc.

[0021] Furthermore, as the biodegradable plastic, a substance having a glass transition point above room temperature is preferable. For example, polylactic acid (PLA) having a melting point of 170° C. and a glass transition point of about 60° C. ), crystalline polylactic acid (CPLA) with a melting point of 166.3°C and a glass transition point of about 60°C, poly-L-lactic acid (PLLA) with a melting point of 180°C and a glass transition point of about 60°C, Examples of the biodegradable plastic include stereocomplex polylactic acid (SC-PLA) having a melting point of about 230° C. and a glass transition point of 35 to 40° C., and the like. Note that as the biodegradable plastic, plastics having a melting point of 200° C. or less and a glass transition point of 50° C. or more are more preferable.

[0022] The soil to be mixed may be river sand, sea sand, mountain sand, reclaimed sand, silt, clay, gravel, mountain soil, soil from a construction site, or sand such as silica sand with a standardized particle size distribution. For example, silica sand is silica sand classified into particle sizes using a sieve with a nominal mesh size of 850 μm, 425 μm, or 300 μm, whose representative value of the particle size distribution (e.g., median, mode, or average value) is 850 μm, 425 μm, or 300 μm. The representative value of the particle size distribution may be a range based on the maximum and minimum particle sizes.

[0023] The pulverizer 11 is, for example, a roller mill, a jet mill, a hammer mill, a pin mill, a rotary mill, etc. The pulverizer 11 may also be a roll crusher, a cutter mill, a cone crusher, etc. The pulverizer 11 may be any pulverizer that can reduce the pellet-shaped biodegradable plastic to a particle size equal to or smaller than the maximum particle size of the soil to be mixed.

[0024] The sieve 12 is, for example, a vibrating sieve, a gyro sifter, a square sifter, etc. The sieve 12 may be capable of filtering biodegradable plastics having a particle size distribution in a predetermined range using two types of mesh filters from the biodegradable plastics crushed by the crusher 11. The sieve 12 may also generate biodegradable plastics having a particle size distribution equal to or smaller than a predetermined mesh value using a filter of one type of mesh.

[0025] The mixer 13 is, for example, a V-type mixer, a W-type mixer, a ribbon-type mixer, a vertical mixer, or the like. The mixer 13 mixes the soil and the biodegradable plastic so that they are uniform. The mixer 13 may be a machine that mixes and stirs to a predetermined depth, such as a stabilizer. Such a mixer 13 may stir the soil and the biodegradable plastic that have been spread on a slope or the like.

[0026] The heater 14 is, for example, a furnace such as a gas furnace or an electric furnace. The heater 14 heats the biodegradable plastic mixed soil placed in a formwork in a furnace or the like to produce construction materials such as blocks and slates. The heater 14 heats the biodegradable plastic mixed soil for a predetermined time to a temperature equal to or higher than the temperature at which the biodegradable plastic melts.

[0027] The heater 14 may be a burner or a road heater. The heater 14 may be a direct heater, or may be an indirect heater such as a dielectric heater such as microwave heating or high frequency heating, or an induction heater. While heating with the heater 14, the ground may be leveled with a laying machine such as a road roller or an asphalt finisher.

[0028] [2. Example of operation of construction material manufacturing system] Next, an example of the operation of the construction material manufacturing system will be described with reference to the drawings.

[0029] Fig. 2 is a flow chart showing an example of an operation for producing a construction material according to the embodiment Fig. 3 is a graph showing an example of a particle size of a biodegradable plastic according to the embodiment.

[0030] As shown in Fig. 2, the construction material manufacturing system 10 pulverizes biodegradable plastic (step S1). Specifically, the pulverizer 11 pulverizes the input biodegradable plastic to generate powdered biodegradable plastic. The pulverizer 11 pulverizes until the proportion of biodegradable plastic having a particle size distribution corresponding to the particle size of the soil to be mixed increases. The input biodegradable plastic may be pellet-shaped biodegradable plastic, fragment-shaped recycled biodegradable plastic, or a mixture of these.

[0031] As shown in Figure 3, for example, pulverized biodegradable plastic with a maximum particle size of 850 μm and a minimum particle size of 100 μm can be obtained. Note that Figure 3 shows the percentage of pulverized biodegradable plastic that passes through filters with meshes of 850 μm, 450 μm, 250 μm, 100 μm, and 75 μm. To make the particles even finer, the pulverization time of the pulverizer 11 can be extended or the blade pitch of the pulverizer 11 can be changed.

[0032] In addition, having a particle size distribution corresponding to the particle size of the soil to be mixed may mean that the representative values ​​of the particle size distribution are close to each other. Also, having a particle size distribution corresponding to the particle size of the soil to be mixed may mean that the particle size is the same as or smaller than the maximum particle size of the soil to be mixed.

[0033] Next, the construction material manufacturing system filters the powdered biodegradable plastic (step S2). Specifically, if the soil to be mixed is sand with an average particle size of about 500 μm, the sieve 12 filters it so that the maximum particle size is 450 μm. If it is desired to keep the particle size within a specified range, the sieve 12 uses two types of filters with different mesh values ​​to generate powdered biodegradable plastic that falls within the specified particle size range.

[0034] The filtering step may be omitted. For example, the filtering step may be omitted if the performance of the pulverizer 11 in the powdering step or the pulverizing time is adjusted so that a particle size distribution corresponding to the particle size of the soil to be mixed is obtained. In addition, when purchasing biodegradable plastic having a predetermined particle size distribution that corresponds to the particle size of the soil to be mixed, the steps S1 and S2 may be omitted.

[0035] Next, the construction material manufacturing system 10 prepares biodegradable plastic mixed soil by mixing the biodegradable plastic with the soil to be mixed (step S3). Specifically, the mixer 13 mixes the powdered biodegradable plastic with the soil to be mixed as homogeneously as possible. The proportion of biodegradable plastic varies depending on the properties, condition, or application of the soil to be mixed. To reduce costs, it is preferable that the proportion of biodegradable plastic is less than that of the soil to be mixed.

[0036] Next, the construction material manufacturing system 10 puts the biodegradable plastic mixed soil into a formwork or lays the biodegradable plastic mixed soil (step S4). Specifically, the biodegradable plastic mixed soil is put into a formwork in the shape of a block or slate, which is a construction material, and is pressed to a certain degree to apply pressure and remove air, thereby making the soil somewhat dense.

[0037] At construction sites, when constructing temporary roads, foundations for temporary cranes, slopes, etc., soil mixed with biodegradable plastics is laid in the target locations. It is made somewhat dense by removing air using a vibrating roller compactor or vibrating plate compactor.

[0038] Next, the construction material manufacturing system 10 performs a heating process (step S5). Specifically, the heater 14 heats the biodegradable plastic mixed soil to a temperature equal to or higher than the melting point (dissolution temperature) of the biodegradable plastic mixed in the soil. The biodegradable plastic mixed soil is placed in the heater 14, which is a furnace, and the heater is turned on. The heater 14, which is a burner or the like, heats the laid biodegradable plastic mixed soil.

[0039] Heating is performed for a predetermined time at a temperature higher than the melting point of the biodegradable plastic but not at which the biodegradable plastic is thermally decomposed, so that the temperature rises near the center of the formwork or to the depth of the laid biodegradable plastic mixed soil, and so that the temperature of the surface on the heater 14 side is not too high above the melting point.

[0040] Next, the construction material manufacturing system 10 solidifies the soil by cooling (step S6). Specifically, the biodegradable plastic mixed soil, which has been heated and has dissolved biodegradable plastic, is cooled naturally to room temperature and solidifies. The biodegradable plastic mixed soil turns into solidified soil. The heated biodegradable plastic mixed soil cools to below the glass transition point of the biodegradable plastic and solidifies.

[0041] Through the above process, construction materials in the form of blocks such as cylinders, cubes, and rectangular parallelepipeds, as well as slate-shaped construction materials, are manufactured. Biodegradable plastic mixed soil is laid, heated, cooled, and solidified to reinforce slopes, road surfaces, site surfaces, etc.

[0042] (Experimental Example) Next, an experimental example will be explained with reference to the figures. The soil to be mixed in the experiment was No. 6 silica sand with a particle size distribution representative value of 425 to 150 μm.

[0043] FIG. 4 is a graph showing an example of the relationship between the strength of the construction material according to the embodiment and the particle size of the biodegradable plastic.

[0044] As shown in Figure 4, the experiment was carried out three times for each of the biodegradable plastics with maximum particle size of 425μm and 850μm, under the same conditions of mixing ratio, heating temperature and heating time. Here, the horizontal axis is the maximum particle size of the biodegradable plastic [mm], and the vertical axis is the uniaxial compressive strength (qu) [MPa]. The mold is cylindrical.

[0045] As shown in Figure 4, when biodegradable plastic with a maximum particle size of 425 μm was mixed, which is close to the representative particle size distribution value of the soil to be mixed, a stronger construction material with an unconfined compressive strength of about 20 MPa was obtained. Even in the case of biodegradable plastic with a maximum particle size of 850 μm, a construction material with an unconfined compressive strength of about 10 to 15 MPa was obtained, which is higher than the strength of several MPa normally required for ground improvement. When biodegradable plastic with a maximum particle size of 425 μm was mixed, there was less variation in strength compared to biodegradable plastic with a maximum particle size of 850 μm.

[0046] Fig. 5 is a graph showing an example of the relationship between the strength and the proportion of biodegradable plastic of the construction material according to the embodiment. Fig. 6 is a graph showing an example of the relationship between the density and the proportion of biodegradable plastic of the construction material according to the embodiment.

[0047] As shown in Figure 5, the addition rate of biodegradable plastic (maximum particle size 425μm) (ratio of biodegradable plastic to biodegradable plastic mixed soil) was 10%, 20%, and 30%, and the heating temperature and heating time were the same, and each experiment was carried out three times. Here, the horizontal axis is the addition rate of biodegradable plastic, and the vertical axis is the uniaxial compressive strength (qu) [MPa]. The formwork was cylindrical.

[0048] As shown in Figure 5, construction materials with greater strength were obtained in proportion to the amount of biodegradable plastic added.

[0049] In addition, as shown in Figure 6, construction materials with almost constant density were obtained even when the ratio of biodegradable plastic added was changed. 3A lightweight construction material was obtained. Here, the horizontal axis is the biodegradable plastic content rate and the vertical axis is the density [g / cm 3 ].

[0050] FIG. 7 is a graph showing an example of the relationship between the strength and heating time of the construction material according to the embodiment.

[0051] As shown in Figure 7, the heating time of the biodegradable plastic mixed soil, the biodegradable plastic addition rate, the maximum particle size of the biodegradable plastic (e.g., 850 μm), and the heating temperature were all performed three times under the same conditions. Here, the horizontal axis is the heating time, and the vertical axis is the uniaxial compressive strength (qu) [MPa]. The formwork is cylindrical. The temperature inside the furnace stabilizes at about t0 after the furnace is switched on, and then three heating times, t1, t2, and t3, were compared. As a result, as shown in Figure 7, there was a tendency for the strength to decrease when the heating time was long, such as t3.

[0052] As described above, according to the construction material manufacturing method of the embodiment, a biodegradable plastic mixed soil is prepared by mixing the soil to be mixed with a biodegradable plastic having a particle size distribution corresponding to the particle size of the soil to be mixed, and the biodegradable plastic mixed soil is heated for a predetermined period of time to a temperature above the melting point of the biodegradable plastic, and then cooled to a temperature below the glass transition point of the biodegradable plastic to solidify it, thereby producing a construction material with improved strength.

[0053] As shown in Figure 8, the sand grains S are bonded together by the vitrified biodegradable plastic P. As the biodegradable plastic P is decomposed by microorganisms, the sand grains S separate and the construction material returns to soil. As shown in Figure 8, the gaps create a permeable construction material. The sand grains S are bonded together in a mesh-like pattern by the vitrified biodegradable plastic P, making the construction material strong despite its light weight. Figure 8 is a schematic diagram created from a microscopic photograph.

[0054] In addition, conventional ground improvement methods that involve injecting into the ground do not provide sufficient strength and there is a large variation in solidification strength, making it difficult to apply to temporary ground that requires strength, such as the foundations of temporary cranes. However, this ground improvement technology can create ground that is as strong as concrete but has little variation in strength by powdering biodegradable plastic, and then melting and solidifying it, so it can be applied to temporary ground that requires strength.

[0055] It is lighter than temporary materials improved with conventional cement and has the same strength, and does not need to be removed after construction, which reduces costs. It can also be used as an environmentally friendly temporary material that does not spread harmful substances such as hexavalent chromium.

[0056] By heating the entire biodegradable plastic mixed soil at the melting temperature of the biodegradable plastic for a relatively short period of time, it is possible to produce high-strength, lightweight degradable plastic solidified soil.

[0057] In addition, if the proportion of biodegradable plastic is less than that of the soil to be mixed, less biodegradable plastic will be required, resulting in lower costs.

[0058] Furthermore, when the biodegradable plastic has a melting point of 200°C or less and a glass transition point of 50°C or more, the glass transition point is above room temperature (25°C), so it can maintain its strength at room temperature compared to asphalt, which has a glass transition point of -15°C to -37°C. In particular, biodegradable plastics with a glass transition point of 50°C or more can maintain sufficient strength even at a summer temperature of 40°C, compared to asphalt, which has a softening point of 47°C to 55°C. Furthermore, biodegradable plastics with a melting point of 200°C or less can be melted without the need to raise the temperature of heater 14 above 200°C, making manufacturing and construction easier.

[0059] In addition, if the representative value of the particle size distribution of the soil to be mixed corresponds to the representative value of the particle size distribution of the biodegradable plastic, the soil and the biodegradable plastic will be easier to mix if their representative values ​​of particle size distribution are close. By powdering the biodegradable plastic to a size smaller than the maximum particle size of the soil to be mixed, it becomes easier to mix them uniformly.

[0060] In addition, the strength of the solidified soil changes depending on the heating time and the particle size of the biodegradable plastic, so by adjusting these, it is possible to produce solidified soil of the required strength. In addition, while the strength normally required for ground improvement is several MPa, using biodegradable plastic has a high strength of 20 MPa and a density of 1.4 g / cm 3 It can be used as a lightweight construction material, temporary foundation, and temporary earth structure.

[0061] Furthermore, if the biodegradable plastic mixed soil is placed in a formwork and compressed before the heating step, stronger construction materials, temporary ground, temporary earth structures, etc. can be obtained.

[0062] This biodegradable plastic mixed soil is a mixture of soil to be mixed with biodegradable plastic having a particle size distribution corresponding to the particle size of the soil to be mixed, and the ratio of biodegradable plastic is less than that of the soil to be mixed. By using this biodegradable plastic mixed soil, which is easily laid on road surfaces, slopes, ground, etc. and heat-treated and cooled to harden, it is possible to carry out reinforcement work for road surfaces, slopes, ground, etc. that are biodegradable and have improved strength. By placing this biodegradable plastic mixed soil in a formwork, heat-treated, cooled and hardened, it is possible to manufacture construction materials that are biodegradable and have improved strength. In addition, since only a small amount of biodegradable plastic is required, costs are reduced.

[0063] According to the ground solidification method of the embodiment, a biodegradable plastic mixed soil, which is a mixture of soil to be mixed with a biodegradable plastic having a particle size distribution corresponding to the particle size of the soil to be mixed, is laid on the ground, the laid biodegradable plastic mixed soil is heated for a predetermined time above the temperature at which the biodegradable plastic melts, and the heated biodegradable plastic mixed soil is cooled to a temperature below the glass transition point of the biodegradable plastic to solidify, thereby solidifying the ground with improved strength. In particular, even on slopes with inclinations, it is possible to carry out construction to protect the slopes with improved strength and biodegradability.

[0064] [3. Examples of construction materials] Next, examples of construction materials will be described with reference to drawings.

[0065] 9 and 10 are schematic diagrams showing an example of a construction example to which the construction material according to the embodiment is applied.

[0066] As shown in Figure 9, it can also be used as a slope protection material. By laying biodegradable plastic mixed soil on embankment e, and then heating and cooling it, it becomes a slope or slope protection material s. As biodegradable plastic gradually decomposes, it can also be used for slope planting work and greening foundation work.

[0067] As shown in Figure 10, it may be used as an earth structure made of precast members B. The precast members B made from biodegradable plastic mixed soil molded into blocks are piled up to create an earth structure. Depending on the strength, it may be used as an embankment, an earth retaining wall, or an interlocking block (permeable paving material).

[0068] Alternatively, the biodegradable plastic mixed soil may be molded into granules, heated and melted, and then cooled and solidified. The granular biodegradable plastic solidified soil may be used instead of gravel as a soft ground covering material to reduce the muddyness of the ground by simply laying it on soft ground containing mud or a large amount of water. In this case, the granular biodegradable plastic solidified soil will biodegrade over time, and all the gravel will be returned to the soil.

[0069] Biodegradable plastic solidified soil may also be used as a temporary ground for earthworks. Biodegradable plastic mixed soil is laid using a laying machine such as an asphalt finisher, heated and melted by a heater 14, and then cooled and solidified to form a temporary ground of biodegradable plastic solidified soil. It can be used instead of steel sheets or permeable paving materials used for construction access roads, temporary roads, soft ground covering, work site curing, etc. Slate-like biodegradable plastic solidified soil may also be laid as a temporary ground.

[0070] Furthermore, the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention. [Explanation of symbols]

[0071] 10: Construction material manufacturing system P: Biodegradable plastic S: Sand grains (soil to be mixed) s:Protective material B: Precast materials (construction materials)

Claims

1. A powdering step of powdering the biodegradable plastic pellets; A filtering step of filtering the powdered biodegradable plastic with a filter having a predetermined mesh value; A mixing step of generating a biodegradable plastic mixed soil by mixing the soil to be mixed with the filtered biodegradable plastic; A heating step of heating the biodegradable plastic mixed soil at a temperature equal to or higher than the melting temperature of the biodegradable plastic and at a temperature at which the biodegradable plastic does not thermally decompose for a predetermined time according to the mesh value of the filter; A solidification step of cooling the heated biodegradable plastic mixed soil to a temperature equal to or lower than the glass transition point of the biodegradable plastic and solidifying it; A method for manufacturing a construction material, comprising:

2. In the construction material manufacturing method according to claim 1, The construction material manufacturing method is characterized in that the filtering step filters the powdered biodegradable plastic using two types of filters with different mesh values ​​so that the particle size falls within a predetermined range.

3. In the construction material manufacturing method according to claim 1 or 2, A method for manufacturing construction materials, characterized in that the proportion of the biodegradable plastic is less than that of the soil to be mixed.

4. In the construction material manufacturing method according to claim 1 or 2, A method for manufacturing construction materials, characterized in that the biodegradable plastic is polylactic acid.

5. In the construction material manufacturing method according to claim 1 or 2, A method for manufacturing construction materials, characterized in that the biodegradable plastic is a polymer made from natural products.

6. A powdering step of powdering the biodegradable plastic pellets; A filtering step of filtering the powdered biodegradable plastic with a filter having a predetermined mesh value; A laying step of laying the biodegradable plastic mixed soil obtained by mixing the soil to be mixed with the filtered biodegradable plastic on the ground; A heating step of heating the laid biodegradable plastic mixed soil at a temperature equal to or higher than the melting temperature of the biodegradable plastic but not thermally decomposing the biodegradable plastic for a predetermined time according to the mesh value of the filter; A solidification step of cooling the heated biodegradable plastic mixed soil to a temperature equal to or lower than the glass transition point of the biodegradable plastic and solidifying it; A ground solidification method comprising the steps of:

7. The ground solidification method according to claim 6, A ground solidification method characterized by further comprising a compression step of compressing the biodegradable plastic mixed soil by vibration after the biodegradable plastic mixed soil is laid.

Images