Plant waste plant material vegetation concrete and preparation method thereof

Abstract

The present invention discloses a plant waste plant material vegetation concrete and its preparation method. The plant waste plant material vegetation concrete comprises the following raw materials, by weight: 15 parts plant waste aggregate, 25-40 parts cementitious material, 15-25 parts pore-filling soil, and 15-30 parts surface soil. The plant waste plant material vegetation concrete according to the present invention uses plant waste as lightweight aggregate and improved magnesium oxychloride cement as the cementitious material. The pore-filling soil and surface soil have strong water and fertilizer retention capabilities.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste-free urban organic waste disposal and concrete, and in particular relates to a plant waste and plant material-grown concrete. Background Art

[0002] Vegetative concrete refers to a type of concrete or concrete product that uses a specially formulated concrete structure with a specific pore size and porosity as its framework. The pores are filled with substances necessary for plant growth, allowing plant roots to grow within the pores or penetrate the concrete and grow in the underlying soil. This concrete primarily serves to beautify and green slopes and banks, as well as stabilize soil and water. Currently, vegetative concrete primarily consists of coarse aggregate, cementitious materials, planting materials, and additives. Coarse aggregate includes crushed stone, pebbles, and recycled aggregate; cementitious materials are typically ordinary Portland cement; planting materials include soil, fertilizer, and water-retaining agents; and additives primarily include water reducers and alkali reducers.

[0003] However, the prior art has the following problems:

[0004] 1. The use of natural aggregates is high in strength and heavy in weight: On the one hand, the strength requirements for vegetation concrete are not high in the application scenario, resulting in a waste of resources; on the other hand, the heavy weight causes significant compaction of the underlying soil, affecting the growth of some plant roots;

[0005] 2. The cementitious material used in vegetation concrete is mainly ordinary Portland cement, which has too high alkalinity and is not suitable for plant growth. Alkali reduction treatment affects the strength, stability and durability of the concrete.

[0006] 3. The vegetated concrete has large voids and good permeability, so it needs to add water-retaining agents. However, its long-term water and fertilizer retention capacity is still insufficient.

[0007] 4. Additives include water-retaining agents, water-reducing agents, fertilizers, pesticides, etc. There are many types of materials, the operation is complicated, and it is not easy to mix them evenly, which affects the function of the green concrete.

[0008] 5. The selection and proportion of various materials mainly rely on experience. In particular, if the particle size and porosity of coarse aggregate are not selected properly, it will easily lead to problems such as low porosity or poor strength of the vegetation concrete, resulting in unqualified finished products and waste of resources. Summary of the Invention

[0009] In response to the aforementioned problems with the existing bioremediation concrete, the present invention aims to provide a bioremediation concrete made from plant waste and a method for preparing the same. The bioremediation concrete utilizes plant waste as lightweight aggregate, improved magnesium oxychloride cement as the cementitious material, and a pore-filling soil and surface soil with enhanced water and fertilizer retention capabilities.

[0010] According to one aspect of the present invention, an object of the present invention is to provide a plant waste planting material vegetation concrete, the raw materials of which include the following components in parts by weight: 15 parts of plant waste aggregate, 25 to 40 parts of cementitious material, 15 to 25 parts of pore filling soil, and 15 to 30 parts of surface planting soil.

[0011] More preferably, the raw materials include the following components in parts by weight: 15 parts of plant waste aggregate, 30 to 37.5 parts of cementitious materials, 15 to 20 parts of pore filling soil, and 15 to 20 parts of surface planting soil.

[0012] Preferably, the plant waste aggregate is lignified agricultural and forestry organic waste that is crushed and sieved into wood blocks of a single particle size, with a ratio of maximum particle size to minimum particle size not greater than 1.5:1 to 1:1. Calculated in accordance with the requirements of "Vegetative Concrete" (JC / T 2557-2020), its particle size and porosity must satisfy 6(1-A0) / (A0-0.21) ≤ D ≤ 6(1-A0) / (A0-0.3), and the moisture content is less than 20%. Since the plant waste aggregate is irregular in shape, calculated according to the equivalent particle size, when its shape is a sphere or a cube, its specific surface area is 6 / D, where D is the diameter of the sphere or the side length of the cube, and A0 is the porosity of the plant waste aggregate.

[0013] Preferably, the cementitious material is improved magnesium chloride cement, comprising magnesium oxide, magnesium chloride, water, and potassium dihydrogen phosphate in a molar ratio of (6-9):1:(14-18):(0.15-0.4), wherein the magnesium oxide is calculated as the molar content of active magnesium oxide.

[0014] Preferably, the pore filling soil is a mixture of 80 parts of clay, 5-10 parts of peat, 5-10 parts of vermiculite, 5-10 parts of organic fertilizer, 0.1-0.5 parts of polyacrylamide, and 0.1-0.5 parts of ferrous sulfate, and the particle size of each material is less than 1 mm.

[0015] Preferably, the surface planting soil is a mixture of 80 parts by weight of soil, 10-15 parts by weight of plant waste compost, 5-10 parts by weight of organic fertilizer, and 0.1-0.5 parts by weight of polyacrylamide. The soil is clay or clay loam.

[0016] More preferably, the plant waste compost is agricultural and forestry organic waste, and the compost after crushing and harmlessness meets the requirements of GB / T 31755-2015.

[0017] According to one aspect of the present invention, another object of the present invention is to provide a method for preparing plant waste plant material vegetation concrete, comprising the following steps:

[0018] Step 1: Raw material selection and calculation

[0019] (1) Select plant waste aggregate with the required particle size and porosity, and calculate the required amount of plant waste aggregate according to the area, thickness and material density of the area to be paved, where the material density refers to the plant waste density.

[0020] (2) According to the porosity of the selected plant waste aggregate and the porosity required for the plant material and plant concrete, the amount of required cementitious material M = (A0-A) × C is calculated. Then, according to the molar ratio of magnesium oxide, magnesium chloride, water and potassium dihydrogen phosphate in the cementitious material, the amount of corresponding materials is calculated respectively, where A0 is the porosity of plant waste, A is the designed porosity of plant concrete, and C is the density of cementitious material, which is 1.6-1.9 t / m 3 .

[0021] (3) Raw materials for pore-filling soil: The amount of pore-filling soil is calculated according to the ratio of the pore-filling soil to the plant waste aggregate, and then the amount of soil, peat, vermiculite, organic fertilizer, polyacrylamide, and ferrous sulfate is calculated according to the ratio of each component of the pore-filling soil.

[0022] (4) Raw materials of surface planting soil: the amount of surface soil is calculated according to the ratio with the plant waste aggregate, and then the amount of soil, plant waste compost, organic fertilizer and polyacrylamide is calculated according to the ratio of each component of the surface soil.

[0023] Step 2: Preparation of cementitious materials

[0024] First, the magnesium chloride and water in the cementitious material in step 1 are mixed and dissolved in proportion to form brine, potassium dihydrogen phosphate is added, and magnesium oxide is added after mixing. The mixture is mixed evenly until it becomes a paste, ensuring that there are no magnesium oxide particles. The stirring time does not exceed 10 minutes. The cementitious material is used within 120 minutes after preparation. The molar ratio of magnesium chloride to water in the cementitious material is 1:14 to 1:18. If calculated by mass ratio, the purity of the magnesium chloride and the amount of crystal water also need to be considered. Taking magnesium chloride decahydrate with a purity of 100% as an example, the mass ratio is 1:0.92 to 1.18.

[0025] Step 3: Batter coating

[0026] The plant waste aggregate and cementitious material are mixed rapidly in proportion, with the mixing time not exceeding 5 minutes, until the initial fluidity of the cementitious material is between 180 mm and 200 mm.

[0027] Step 4: Material laying

[0028] Place the mixed material in step 3 into a mold or directly spread it on the ground, level the surface and compact it statically at a pressure of 0.2 to 0.3 MPa.

[0029] Step 5: Maintenance

[0030] Cover the surface of the paved material with a layer of plastic film and provide shade when necessary to avoid moisture evaporation, exposure to the sun and rain. In enclosed spaces, attention should also be paid to ventilation and cooling. Remove the covering after 3 to 7 days of maintenance.

[0031] Step 6: Filling the voids with soil

[0032] Mix the soil, peat, vermiculite and organic fertilizer evenly and mix them with water in a mass ratio of 1:1.5 to form a paste. Then, add polyacrylamide and ferrous sulfate into water until they are dissolved, add the paste mixture, mix evenly, continue to add water until the fluidity of the mixture is 180mm~240mm, and use the grouting method to fill the pore filling soil into the pores of the material after curing in step 5.

[0033] Step 7: Covering the topsoil

[0034] Mix the soil, plant waste compost and organic fertilizer in proportion, add polyacrylamide into water until it dissolves, then add the above mixture, add water and mix evenly into a paste. The solid-liquid ratio is controlled to be about 2:1 during the whole process. Evenly cover the surface of the product in step 6 with the paste-like surface planting soil with a thickness of 1 to 3 cm to form the final vegetation concrete.

[0035] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0036] 1. The present invention uses plant waste materials as lightweight aggregate, which is light in weight, has little compaction on the underlying soil, and has high plant compatibility; the plant waste particles are of a single grade, the porosity between the materials is large, and the particle size is accurately calculated and determined based on its porosity, which ensures the porosity and strength of the plant material concrete; and can prevent rework caused by unqualified strength or porosity due to improper construction experience.

[0037] 2. The cementitious material used in the present invention is improved magnesium oxychloride cement, which overcomes the problem of ordinary magnesium oxychloride cement being not water-resistant, and can increase the phosphorus and potassium content of pore-filling soil and soil, reduce the pH value, and does not require alkali reduction treatment, and has good plant compatibility. The fluidity of the cementitious material is used to accurately control the thickness and uniformity of the coarse aggregate slurry, and static pressure molding is used to prevent problems such as slurry accumulation at the bottom of the cementitious material or low strength caused by insufficient slurry thickness.

[0038] 3. Pore-filling soil and surface soil have strong water and fertilizer retention capabilities, which can solve the problem of poor water and fertilizer retention capacity of vegetation concrete. Clay soil is selected as pore-filling soil to enhance soil adhesion and reduce soil erosion. DETAILED DESCRIPTION

[0039] The present invention will be described in detail below. Before describing, it should be understood that the terms used in this specification and the appended claims should not be interpreted as limited to the general meaning and dictionary meaning, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the present invention on the basis of the principle that allows the inventor to appropriately define the terms for the best interpretation. Therefore, the descriptions presented here are merely preferred examples for illustrative purposes and are not intended to limit the scope of the present invention. It should be understood that other equivalents or improvements can be obtained therefrom without departing from the spirit and scope of the present invention.

[0040] Throughout this document, all features or conditions defined as numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered to encompass and specifically disclose all possible subranges and individual values ​​within those ranges, particularly integer values. For example, a description of a range "1 to 8" should be considered to specifically disclose all possible subranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, and so forth, particularly those defined by all integer values, and should be considered to specifically disclose individual values ​​within those ranges such as 1, 2, 3, 4, 5, 6, 7, and 8. Unless otherwise indicated, the foregoing interpretation applies to all of the present disclosure, regardless of whether the ranges are comprehensive or not.

[0041] If a quantity or other value or parameter is expressed as a range, a preferred range, or a series of upper and lower limits, it should be understood that all ranges consisting of any upper limit or preferred value of the range and any lower limit or preferred value of the range have been specifically disclosed herein, regardless of whether these ranges are disclosed separately. In addition, when a numerical range is mentioned herein, unless otherwise specified, the range should include its endpoints and all integers and fractions within the range.

[0042] In this document, numerical values ​​should be understood to have the accuracy of the number of significant digits of the numerical value, provided that the purpose of the invention can be achieved. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0043] The following examples are merely examples of embodiments of the present invention and do not constitute any limitation thereto. Those skilled in the art will appreciate that modifications without departing from the spirit and scope of the present invention fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are commercially available products.

[0044] The vegetation concrete according to the present invention can be prepared according to the following specific method.

[0045] Step 1: Raw material selection and calculation

[0046] According to the industry standard "Botanical Concrete" (JC / T 2557-2020), the main indicators of botanical concrete are compressive strength and porosity. The main factors affecting porosity are the porosity of the coarse aggregate plant waste and the proportion of cementitious materials; the main factors affecting compressive strength are the particle size of the coarse aggregate plant waste and the proportion of cementitious materials. The porosity of the coarse aggregate plant waste is mainly affected by its shape, particle size, arrangement, and particle gradation. Irregular shapes and single gradations favor increased porosity. A greater proportion of cementitious materials increases the strength and decreases the porosity of the botanical concrete. However, excessive cementitious materials can cause them to separate under gravity and accumulate at the bottom, affecting permeability. Therefore, the principle of raw material selection is to choose plant waste particle sizes that have a higher porosity and require less cementitious materials.

[0047] (1) Selection of plant waste

[0048] The smaller the particle size, the larger the specific surface area of ​​the material, the more cementitious material attached to it, and the more contact points between the materials. The resulting plant-based concrete has relatively small porosity and greater strength. When the surface of plant waste is just covered with a 1mm thick cementitious material, there is strong adhesion between the materials and the cementitious material will not separate. According to the requirements of "Plant-based Concrete" (JC / T 2557-2020), the porosity range of plant-based concrete is 21% to 30%. The relationship between material particle size and porosity is:

[0049] 21% ≤ A0-(1-A0)B*L ​​≤ 30% (1)

[0050] In the formula: --

[0051] A0--porosity of plant waste;

[0052] B--specific surface area of ​​plant waste;

[0053] L—the adhesion thickness of cementitious material is 1mm.

[0054] Calculated:

[0055] (A0-30%) / [(1- A0)L] ≤ B ≤ ((A0-21%) / [(1- A0)L] (2)

[0056] Since plant waste is irregular in shape, according to the equivalent particle size, when its shape is sphere or cube, its specific surface area is 6 / D (D is the diameter of the sphere or the side length of the cube, unit is mm), and it is substituted into (2) to obtain:

[0057] 6(1- A0) / (A0-0.21) ≤ D ≤ 6(1- A0) / (A0-0.3) (3)

[0058] Since the porosity of single-graded materials varies little, the porosity of single-graded plant waste aggregates is generally between 40% and 55%. The appropriate particle size ranges for plant waste aggregates with different porosities are calculated according to formula (3) as shown in Table 1:

[0059] Table 1

[0060]

[0061] Use a standard sieve to sieve the crushed plant waste into multiple single particle size groups, that is, the ratio of the maximum particle size to the minimum particle size is not greater than 1.5:1. Measure the porosity of each group and select the plant waste whose particle size and porosity meet the requirements of sequence number (3) in Table 1. Calculate the required volume of plant waste according to the range and thickness of the area to be laid.

[0062] (2) Based on the porosity of the selected plant waste and the designed porosity of the bioreinforced concrete, calculate the amount of cementitious material M required per unit volume of bioreinforced concrete:

[0063] M=(A0-A)×C(4)

[0064] A0--porosity of plant waste;

[0065] A--design porosity of vegetation concrete;

[0066] C - cementitious material density, 1.6-1.9 t / m 3 1.7 t / m 3 count.

[0067] The masses of the corresponding materials are calculated based on the molar ratios of magnesium oxide, magnesium chloride, water and potassium dihydrogen phosphate in the cementitious material in the bioremediation concrete of the present invention.

[0068] (3) Raw materials for pore-filling soil: Calculate the amount of pore-filling soil according to the above ratio, and then calculate the amount of soil, peat, vermiculite, organic fertilizer, polyacrylamide, and ferrous sulfate according to the ratio of each component of the pore-filling soil.

[0069] (4) Raw materials for surface soil: Calculate the amount of surface soil according to the above ratio, and then calculate the amount of soil, plant waste compost, organic fertilizer, and polyacrylamide according to the ratio of each component of the surface soil.

[0070] Step 2: Preparation of cementitious materials

[0071] The magnesium chloride and water in the gelling material are mixed and dissolved in proportion to form brine, potassium dihydrogen phosphate is added, and magnesium oxide is added after mixing and dissolving, and mixed evenly until it becomes a paste, ensuring that there are no magnesium oxide particles. The stirring time does not exceed 10 minutes to prevent the gelling material from solidifying prematurely due to stirring too long. It should be used within 120 minutes after the preparation is completed.

[0072] Step 3: Batter coating

[0073] Add plant waste to the blender and quickly stir the cementitious material until the fluidity is 180mm~200mm. If the fluidity is too high, the cementitious material will not be able to effectively adhere to the surface of the plant waste, affecting the adhesion and strength; if the fluidity is too low, it will cause mixing difficulties and it will be difficult to stir evenly. After adding it to the blender, continue stirring until the cementitious material is evenly wrapped on the surface of the plant waste. The stirring time should not exceed 5 minutes to prevent the material from solidifying prematurely.

[0074] Step 4: Material laying

[0075] Place the mixed material into a mold or directly spread it on the ground. The laying thickness should be 10% to 20% higher than the designed thickness. After the surface is smoothed, it should be statically compacted at a pressure of 0.2 to 0.3 MPa.

[0076] Step 5: Maintenance

[0077] During the curing process, heat is released, causing the temperature of the eco-cover to rise. On the one hand, high temperature favors the formation of Mg(OH)2, which has a lower hydration heat, but is not conducive to the formation of 518 phase, which has a higher hydration heat, resulting in reduced strength. On the other hand, due to the large amount of water evaporation, salt will be transferred to the surface along with the water vapor to form brine. Cover the surface of the paved material with a layer of plastic film and provide shade when necessary to avoid water evaporation, exposure to the sun, and rain. When making molds in a confined indoor space, pay attention to ventilation and cooling. Remove the covering after 3-7 days of curing.

[0078] Step 6: Filling the voids with soil

[0079] Mix the soil, peat, vermiculite and organic fertilizer evenly and then mix them with water in a mass ratio of 1:1.5 to form a paste. Then dissolve polyacrylamide and ferrous sulfate in water respectively and add them into the mixture. Mix evenly and continue to add water until the fluidity of the mixture is 180mm~240mm (too high fluidity will result in too little pore-filling soil, and too low fluidity will make filling difficult). Use the grouting method to fill the pore-filling soil into the pores.

[0080] Step 7: Covering the topsoil

[0081] Mix soil, plant waste compost and organic fertilizer in proportion, dissolve polyacrylamide in water and add to the mixture, mix evenly while adding water to form a paste, and evenly cover the surface with the paste-like topsoil to a thickness of 1 to 3 cm.

[0082] Example 1: Preparation of 22% Porosity Vegetation Concrete

[0083] Plant waste (such as wood chips or bark) is crushed into 9.5-90 mm blocks and sieved through a standard sieve to be divided into 9 groups, as shown in Table 2 below. Groups 2 and 4 meet the requirements of Table 1, and plant waste from Group 2 is selected as the raw material.

[0084] Table 2

[0085]

[0086] Add 15kg of tap water into the blender, add 12kg of 98% pure magnesium chloride, stir until the magnesium chloride is completely dissolved, then add 1kg of potassium dihydrogen phosphate and stir to dissolve; add 40kg of 70% active light-burned magnesium oxide powder into the blender, continue stirring to mix the slurry evenly, let it stand for 30 minutes (fluidity 190mm), then continue stirring while adding 30kg of plant waste aggregate from Group 2, and continue stirring until all the components are evenly mixed. Place the mixed materials into a mold, smooth the surface, and then statically compact under a pressure of 0.3 MPa for 30 minutes; cover with plastic film and place in a cool place for 7 days, then take out and place on the surface; grind 10 kg of clay, 2 kg of peat, 1 kg of vermiculite, and 1 kg of organic fertilizer in a grinder, then add them to a blender, and add 20 kg of tap water while stirring; dissolve 0.05 kg of polyacrylamide in 5 kg of water and add it to the blender for stirring, dissolve 0.05 kg of ferrous sulfate in 1 kg of water and add it to the blender for stirring, and continue to add 2 kg of water and stir evenly; pressure-grout the mixture into the above-mentioned prefabricated vegetation and planting material concrete blocks until all the pores are filled; dissolve 0.05 kg of polyacrylamide in 5 kg of water, then add 10 kg of clay loam, 2 kg of plant waste compost, and 1 kg of organic fertilizer and mix evenly to form a paste-like surface soil, which is spread evenly on the surface of the above-mentioned vegetation and planting material concrete blocks.

[0087] Example 2

[0088] Add 100 kg of tap water into the blender, add 80 kg of 98% pure magnesium chloride, stir until the magnesium chloride is completely dissolved, then add 5 kg of potassium dihydrogen phosphate and stir to dissolve; add 300 kg of 60% activity light-burned magnesium oxide powder into the blender, continue stirring until the slurry is evenly mixed, let it stand for 15 minutes (fluidity 185 mm), then continue stirring while adding 300 kg of plant waste aggregate from Group 4, and continue stirring until all the ingredients are evenly mixed. The mixed materials were evenly spread on the leveled ground, and after the surface was smoothed, statically compacted at a pressure of 0.3 MPa for 10 minutes; covered with plastic film and geotextile for 7 days, and then the covering was removed; 100 kg of clay, 30 kg of peat, 5 kg of vermiculite, and 5 kg of organic fertilizer were crushed in a grinder, and then added to a mixer, and 200 kg of tap water was added while stirring; 0.2 kg of polyacrylamide was dissolved in 30 kg of water and added to the mixer for stirring, and 0.1 kg of ferrous sulfate was dissolved in 10 kg of water and added to the mixer for stirring; the mixture was pressure-grouted into the above-mentioned prefabricated vegetation and planting material concrete blocks until all the pores were filled; 0.2 kg of polyacrylamide was dissolved in 50 kg of water, and then 100 kg of clay, 15 kg of plant waste compost, and 5 kg of organic fertilizer were added and mixed evenly into a paste-like topsoil, which was spread evenly on the surface of the above-mentioned vegetation and planting material concrete blocks.

[0089] Comparative Example 1

[0090] Comparative Example 1 is based on Example 1, except that "10 kg of clay loam" is replaced by "10 kg of sandy loam", and the rest is the same as Example 1.

[0091] Comparative Example 2

[0092] Comparative Example 2 is based on Example 1, and differs from Example 1 only in that potassium dihydrogen phosphate is not added.

[0093] Comparative Example 3

[0094] Add 47 kg of ordinary Portland cement into a blender, add 13 kg of tap water while stirring, and stir evenly; add 300 kg of 16-31.5 mm crushed stone into the above slurry, and continue stirring until all parts are mixed evenly; the subsequent operation is the same as in Example 1.

[0095] Performance testing

[0096] The following performance tests were performed on the vegetation concrete prepared in Examples 1-2 and Comparative Examples 1-3, and the test results are shown in Table 1:

[0097] pH value: One month later, the soil in the gap of the vegetation concrete was taken and the soil pH value was measured using the "1239-1999 Determination of pH Value of Forest Soil".

[0098] Density: After cutting the sample with a knife or saw, rinse away all soil and grind it into a standard rectangular parallelepiped. Measure the sample dimensions with a vernier caliper and then weigh it to calculate the density. The weight is the weight after drying in an oven at 105 degrees Celsius to a constant weight.

[0099] Moisture content: Test the moisture content of the topsoil after one month.

[0100] Stability: After one year, observe the condition of the vegetation concrete on site to see if it is cracked or broken when stepped on.

[0101] Table 1 Test results of examples and comparative examples

[0102]

[0103] Analysis of the above test results:

[0104] Analysis of the pH value data of Example 1, Example 2 and Comparative Example 3 shows that the alkalinity of the plant material and plant concrete of the present invention is significantly lower than that of the traditional plant concrete (Comparative Example 3), which solves the problem that the traditional plant concrete causes alkalinization of the soil therein, affecting the soil environmental quality and plant growth.

[0105] Analyzing the density data of Example 1, Example 2 and Comparative Example 3, the density of the planting material concrete of the present invention is significantly lower than that of the traditional planting concrete (Comparative Example 3). On the one hand, it is beneficial to the installation and transportation of the material. On the other hand, it causes less compaction of the soil underneath, which is beneficial to the growth of plant roots.

[0106] Analysis of the moisture content data of Example 1, Example 2 and Example 1 shows that the surface planting soil based on clay soil has a stronger water retention capacity than loam and is more conducive to plant growth.

[0107] Analysis of the stability observations of Example 1, Example 2 and Comparative Example 2 shows that the plant material and plant concrete without potassium dihydrogen phosphate (Comparative Example 2) has poor stability and obvious magnesium chloride hydrolysis and brine reversion phenomenon. It can be seen that potassium dihydrogen phosphate enhances the water resistance of the cementitious material.

[0108] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A plant waste plant material plant concrete, the raw materials of which include the following components in parts by weight: 15 parts of plant waste aggregate, 25-40 parts of cementitious material, 15-25 parts of pore filling soil, and 15-30 parts of surface planting soil; The plant waste aggregate is lignified agricultural and forestry organic waste that has been crushed and sieved into wood blocks of a single particle size, with a maximum particle size to minimum particle size ratio of no more than 1.5:1 to 1:1, and its particle size and porosity must satisfy 6(1- A0) / (A0-0.21)≤ D ≤ 6(1- A0) / (A0-0.3), and a moisture content of less than 20%. Since the plant waste aggregate is irregular in shape, according to the equivalent particle size calculation, when its shape is a sphere or a cube, its specific surface area is 6 / D, where D is the diameter of the sphere or the side length of the cube, and A0 is the porosity of the plant waste aggregate; The cementitious material is improved magnesium chloride cement, comprising magnesium oxide, magnesium chloride, water and potassium dihydrogen phosphate in a molar ratio of (6-9): 1: (14-18): (0.15-0.4), wherein the magnesium oxide is calculated based on the molar content of active magnesium oxide; The pore filling soil is a mixture of 80 parts of clay, 5-10 parts of peat, 5-10 parts of vermiculite, 5-10 parts of organic fertilizer, 0.1-0.5 parts of polyacrylamide, and 0.1-0.5 parts of ferrous sulfate, and the particle size of each material is less than 1 mm. In parts by weight, the surface planting soil is a mixture of 80 parts by weight of soil, 10 to 15 parts by weight of plant waste compost, 5 to 10 parts by weight of organic fertilizer, and 0.1 to 0.5 parts by weight of polyacrylamide. The soil is clay or clay loam.

2. The plant waste plant material vegetation concrete according to claim 1, characterized in that: The raw materials include the following components in parts by weight: 15 parts of plant waste aggregate, 30 to 37.5 parts of cementitious materials, 15 to 20 parts of pore filling soil, and 15 to 20 parts of surface planting soil.

3. The plant waste plant material vegetation concrete according to claim 1 or 2, characterized in that: The plant waste compost is agricultural and forestry organic waste that has been crushed and rendered harmless.

4. The method for preparing plant waste plant material vegetative concrete according to any one of claims 1 to 3, comprising the following steps: Step 1: Raw material selection and calculation (1) Select plant waste aggregate with the required particle size and porosity, and calculate the required amount of plant waste aggregate according to the area, thickness and material density of the area to be paved, where the material density refers to the density of plant waste; (2) According to the porosity of the selected plant waste aggregate and the porosity required for the plant material and plant concrete, the amount of required cementitious material M = (A0-A) × C is calculated. Then, according to the molar ratio of magnesium oxide, magnesium chloride, water and potassium dihydrogen phosphate in the cementitious material, the amount of corresponding materials is calculated respectively, where A0 is the porosity of plant waste, A is the designed porosity of plant concrete, and C is the density of cementitious material, which is 1.6-1.9 t / m 3 ; (3) Raw materials for pore filling soil: Calculate the amount of pore filling soil according to the ratio of pore filling soil to plant waste aggregate, and then calculate the amount of clay, peat, vermiculite, organic fertilizer, polyacrylamide, and ferrous sulfate according to the ratio of each component of the pore filling soil; (4) Raw materials of surface planting soil: Calculate the amount of surface planting soil according to the ratio of plant waste aggregate, and then calculate the amount of soil, plant waste compost, organic fertilizer, and polyacrylamide according to the ratio of each component of the surface planting soil; Step 2: Preparation of cementitious materials First, the magnesium chloride and water in the gelling material in step 1 are mixed and dissolved in proportion to form brine, potassium dihydrogen phosphate is added, and after mixing, magnesium oxide is added and mixed evenly until a paste is formed, ensuring that there are no magnesium oxide particles. The stirring time does not exceed 10 minutes. The gelling material is used within 120 minutes after preparation. The molar ratio of magnesium chloride to water in the gelling material is 1:14 to 1:18; Step 3: Batter coating Mix plant waste aggregate and cementitious materials in proportion quickly, stirring for no more than 5 minutes, until the initial fluidity of the cementitious materials is between 180 mm and 200 mm; Step 4: Material laying Place the mixed material in step 3 into a mold or directly spread it on the ground, level the surface and compact it statically under a pressure of 0.2-0.3 MPa; Step 5: Maintenance Cover the surface of the paved material with a layer of plastic film. If the space is closed, pay attention to ventilation and cooling. Remove the covering after 3 to 7 days of maintenance. Step 6: Filling the voids with soil Mix clay, peat, vermiculite, and organic fertilizer evenly and mix with water in a mass ratio of 1:1.5 to form a paste. Then, add polyacrylamide and ferrous sulfate to water until dissolved, add to the paste mixture, mix evenly, continue to add water until the fluidity of the mixture is 180 mm to 240 mm, and use grouting to fill the pores of the material after curing in step 5 with pore filling soil; Step 7: Covering the topsoil Mix the soil, plant waste compost and organic fertilizer in proportion, add polyacrylamide into water until it dissolves, then add the above mixture, add water and mix evenly into a paste. The solid-liquid ratio is controlled to be about 2:1 during the whole process. Evenly cover the surface of the product in step 6 with the paste-like surface planting soil with a thickness of 1 to 3 cm to form the final vegetation concrete.

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