Fertilizer-fixing moisturizing vegetation regeneration slope protection concrete and preparation method thereof

Abstract

The invention discloses fertilizer-fixing and moisture-preserving vegetation regeneration slope protection concrete and a preparation method thereof. The concrete is prepared from the following materials in parts by mass: 50 to 70 parts of carbonated regenerated coarse aggregate, 10 to 20 parts of fine aggregate, 5 to 10 parts of slow-release pre-coated fertilizer, 3 to 6 parts of soil-coated seed pellets, 10 to 20 parts of metakaolin-based geopolymer and 5 to 10 parts of water, the slow-release pre-coated fertilizer comprises 1-3 parts of a cementing material and 4-7 parts of a fertilizer; the soil-wrapped seed pellets comprise 1-2 parts of soil and 2-4 parts of seeds; the carbonated recycled coarse aggregate is obtained by carbonating recycled coarse aggregate through CO2 gas. Reutilization of waste concrete resources can be achieved, and the problem of land occupation is solved; the metakaolin-based geopolymer is used for replacing a traditional cement material, the preparation process is simple, and energy consumption and environmental pollution can be reduced; water flow scouring is effectively resisted, the fertilizer efficacy is guaranteed, rooting and germination of seeds are facilitated, and the stability of slope protection is enhanced; the vegetation coverage rate is increased; and the landscape quality is improved.

Description

Technical Field

[0001] The invention belongs to building materials and a preparation method thereof, in particular to a fertilizer-solidifying, moisture-keeping, vegetation-growing, regenerating slope protection concrete and a preparation method thereof. Background Art

[0002] In highway and waterway projects, if the slope loses the stabilizing effect of the slope protection project, local or large-scale collapse may occur, causing a large number of casualties and property losses. Under the action of natural forces such as rain scouring and wind erosion, the loss of soil and sediment on the slope causes siltation in the river channel, increases the risk of flood disasters, and destroys the ecological balance of the region.

[0003] Patent CN111517707A discloses an ecological slope protection concrete and its construction method, in which grass seeds are placed in the surface concrete; Patent CN117819935A discloses a design method for recycled aggregate vegetation concrete based on magnesium phosphate cement. The roots of plants grown in existing slope protection concrete are shallow, and their ability to resist water erosion is weak, and fertilizers cannot be slowly released to continuously supply fertilizer for plant growth, resulting in plant death; at the same time, existing slope protection concrete still relies on the use of cement materials, and there is no technical solution for using kaolin-based polymers to completely replace traditional cement materials for the preparation of vegetation regeneration slope protection concrete. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a vegetation regeneration slope protection concrete that utilizes waste concrete resources, is beneficial to seed rooting and germination, and achieves solid fertilizer, moisture retention and anti-scouring; another purpose of the present invention is to provide a preparation method of solid fertilizer, moisture retention and vegetation regeneration slope protection concrete.

[0005] Technical solution: The solid fertilizer, moisture-retaining, vegetation-growing and regenerated slope protection concrete described in the present invention comprises the following materials in parts by mass: 50-70 parts of carbonated recycled coarse aggregate, 10-20 parts of fine aggregate, 5-10 parts of slow-release pre-coated fertilizer, 3-6 parts of soil-wrapped seed pellets, 10-20 parts of metakaolin-based polymer and 5-10 parts of water; the slow-release pre-coated fertilizer comprises 1-3 parts of binder and 4-7 parts of fertilizer; the soil-wrapped seed pellets comprise 1-2 parts of soil and 2-4 parts of seeds; the carbonated recycled coarse aggregate is obtained by carbonation treatment of the recycled coarse aggregate with CO2 gas.

[0006] Furthermore, the recycled coarse aggregate is obtained by crushing, screening, impurity removal, cleaning and drying the concrete from abandoned buildings and bridges. The particle size is 4.75mm-26.5mm, the target void ratio is 18%-28%, and the apparent density is not less than 2300kg / m 3 , bulk density not less than 1200kg / m 3 .

[0007] Furthermore, the reaction time of CO2 gas carbonation treatment is 12-24h, the CO2 gas concentration is 30%-50%, and the reaction temperature is 20-40°C.

[0008] Furthermore, the content of Al2O3 in the metakaolin-based polymer is 35%-45% by mass, and the content of SiO2 is 45%-55% by mass; the metakaolin-based polymer is obtained by reacting metakaolin with an activator, and the metakaolin is obtained by dehydrating kaolin by calcining it at a temperature of 600°C-900°C for 2-4h; the activator is a potassium hydroxide solution with a molar concentration of 2-4mol / L.

[0009] Furthermore, the fine aggregate is red mud or diatomaceous earth, and the water absorption rate is 100%-200%; the porosity of the red mud is 30%-50%, and the bulk density is 0.7-1.0g / cm 3 , pH value is 7-9; porosity of diatomaceous earth is 80%-90%, bulk density is 0.3-0.5g / cm 3 , pH value is 5-7.

[0010] Furthermore, the binder material is gum arabic powder with a particle size of 100-200 μm.

[0011] Furthermore, the fertilizer is solid particles of ammonium sulfate or potassium sulfate, and the fertilizer purity reaches more than 95%; the nitrogen content of the solid particles of ammonium sulfate is 20%-30%; the K2O content of the solid particles of potassium sulfate is 40%-60% and the water solubility is greater than 90%.

[0012] Furthermore, the soil is loess or silty clay, and the soil collapsibility coefficient δs is greater than 0.015.

[0013] Furthermore, the seeds include bermudagrass and zoysia grass, the purity of the seeds is more than 90%, the water content is between 7% and 12%, and the germination rate is greater than 90%.

[0014] The method for preparing a solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete of the present invention comprises the following steps:

[0015] (1) placing the recycled coarse aggregate in a closed reaction container, and introducing CO2 gas into the container to obtain carbonated recycled coarse aggregate;

[0016] (2) performing water-retaining treatment on the fine aggregate after screening and impurity removal to obtain water-absorbing fine aggregate;

[0017] (3) placing solid fertilizer particles into a bed of a fluidized bed coating machine, turning on the airflow to suspend the solid fertilizer particles in a fluidized state, and then spraying the cementing material solution evenly on the solid fertilizer particles multiple times until an elastic transparent coating layer is formed on the surface of the solid fertilizer particles, thereby obtaining a slow-release pre-coated fertilizer;

[0018] (4) placing seeds and soil into a rotary pelletizer, spraying water while rotating, so that the pellet structure is formed during the uniform tumbling process, and collecting soil-coated seed pellets with a diameter of 5-10 mm;

[0019] (5) putting the carbonated regenerated coarse aggregate obtained in step (1) and the water-absorbing fine aggregate obtained in step (2) into a stirring device for stirring to obtain a uniform mixture;

[0020] (6) Putting the metakaolin-based polymer and the mixture obtained in step (5) into a stirring device, adding water for wet mixing, then adding the slow-release pre-coated fertilizer obtained in step (3) until a uniform mixture is formed, and finally adding the soil-wrapped seed pellets obtained in step (4), and uniformly stirring to obtain a fertilizer-solidifying, moisture-retaining, vegetation-growing, and regenerating slope protection concrete.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0022] 1. Realize the recycling of waste concrete resources and alleviate the land occupation problem of construction solid waste; use kaolin-based polymers instead of traditional cement materials, the preparation process is simple and easy, which can reduce energy consumption and environmental pollution;

[0023] 2. Enhanced water permeability reduces soil erosion, effectively resists water erosion, ensures fertilizer effectiveness, facilitates seed rooting and germination, and enhances the stability of slope protection;

[0024] 3. Increase the vegetation coverage of slope protection, form a stable ecosystem, and improve the quality of the landscape. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0026] In the following examples, the materials and reagents used are all commercially available unless otherwise specified. Experimental methods without specific conditions in the examples are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0027] Example 1

[0028] The solid fertilizer moisturizing vegetation regeneration slope protection concrete includes the following materials by mass: 50 parts of carbonated recycled coarse aggregate, 10 parts of fine aggregate, 5 parts of slow-release pre-coated fertilizer, 3 parts of soil-wrapped seed pellets, 10 parts of metakaolin-based polymer and 5 parts of water; the recycled coarse aggregate is carbonated with CO2 gas; the gradation of the recycled coarse aggregate is shown in Table 1, the target void ratio is 18%, and the apparent density is 2450 kg / m 3 , bulk density 1365kg / m 3， The comparison of recycled aggregate before and after carbonation is shown in Table 2.

[0029] Table 1 Recycled coarse aggregate gradation

[0030] Screen size mm 26.5 19 16 13.2 9.5 4.75 Pass Rate % 82 67 55 40 22 0

[0031] Table 2 Comparison of recycled coarse aggregate before and after carbonation

[0032] Recycled coarse aggregate Carbonated recycled coarse aggregate Porosity % 18.6 18.6 Compressive strengthMpa 13.1 15.8

[0033] The fine aggregate is diatomaceous earth, with a porosity of 85% and a bulk density of 0.36 / cm 3 , pH value is 5.3.

[0034] The slow-release pre-coated fertilizer is composed of 4 parts of fertilizer and 1 part of cementing material. The cementing material is gum arabic powder, and the fertilizer is ammonium sulfate solid particles. The fertilizer purity reaches 95.3%, the nitrogen content is 24%, and the water solubility rate is 91%.

[0035] The soil-wrapped seed pellets consist of 1 part soil and 2 parts seeds. The soil is loess with a collapsibility coefficient of δs of 0.03, and the seeds are bermudagrass with a purity of 96%, a water content of 7.8%, and a germination rate of 98%.

[0036] The Al2O3 content of the metakaolin-based polymer is 35% by mass and the SiO2 content is 45% by mass.

[0037] The molar concentration of the activator potassium hydroxide solution is 2 mol / L.

[0038] The preparation method of the solid fertilizer moisturizing vegetation regeneration slope protection concrete comprises the following steps:

[0039] (1) crushing, screening, removing impurities, washing and drying concrete from dismantled abandoned buildings and bridges to obtain recycled coarse aggregate, taking 50 parts of the recycled coarse aggregate for carbonation treatment in a closed container, introducing carbon dioxide gas with a concentration of 30% for 12 hours, and controlling the reaction temperature at 20° C. to obtain carbonated recycled coarse aggregate;

[0040] (2) 10 parts of diatomaceous earth are taken and impurities are removed, and then water is retained for 2 hours to make its water absorption rate reach 160%, thereby obtaining water-absorbing fine aggregate;

[0041] (3) placing 4 parts of ammonium sulfate solid granular fertilizer into the bed of a fluidized bed coating machine, turning on the airflow to suspend the fertilizer solid particles in a fluidized state, and then dissolving 1 part of gum arabic powder in water to obtain a solution, and spraying the solution evenly on the fertilizer particles for multiple times to form an elastic transparent coating layer on the surface of the fertilizer particles, thereby obtaining a slow-release pre-coated fertilizer;

[0042] (4) Put 2 parts of bermudagrass seeds and 1 part of loess into a rotary pelletizer, spray water while rotating, and set the speed to 15 r / min to form a pellet structure during the uniform tumbling process, and collect soil-coated seed pellets with a diameter of 5-10 mm;

[0043] (5) 10 parts of kaolin are placed in a high temperature device and calcined at 600° C. for 2 h and dehydrated to obtain metakaolin, 1 part of the activator solution is added to the metakaolin and stirred until a uniform paste-like mixture is formed to obtain a metakaolin-based polymer;

[0044] (6) The carbonated regenerated coarse aggregate obtained in step (1) is graded, the target porosity is 19%, and the measured porosity is 18.6%. 10 portions of the fine aggregate obtained in step (2) are put into a stirring device and slowly stirred until a uniform mixture is obtained. The speed is set to 10 r / min and the stirring time is 30 s.

[0045] (7) 10 parts of the metakaolin-based polymer obtained in step (5) and the mixture obtained in step (6) are put into a mixing device, 5 parts of water are added for wet mixing, and wet mixing is performed at a speed of 20 r / min for 60 seconds. Then, 4 parts of the slow-release pre-coated fertilizer obtained in step (3) are added and stirred until a uniform concrete mixture is formed. Finally, 3 parts of the soil-coated seed pellets obtained in step (4) are added and stirred evenly to obtain a solid fertilizer, moisture-retaining, vegetation-regenerating slope protection concrete.

[0046] The performance of the prepared solid fertilizer moisture-retaining vegetation regeneration slope protection concrete was tested by pouring 150mm*150mm*150mm standard specimens, and the test results of 28d compressive strength, 28d flexural strength, pH value, 30d fertilizer residual nitrogen content, water permeability coefficient and seed survival rate were tested as shown in Table 3:

[0047] Table 3 Performance of concrete for slope protection with solid fertilizer, moisture retention and vegetation regeneration

[0048] Detection indicators Test results 28d compressive strength / MPa 18.1 28d flexural strength / MPa 3.5 pH 8.1 30d fertilizer residual nitrogen content% 14.5 Water permeability cm / s 0.46 Seed survival rate / % 94

[0049] Example 2

[0050] The solid fertilizer moisturizing vegetation regeneration slope protection concrete includes the following materials by mass: 55 parts of carbonated recycled coarse aggregate, 13 parts of fine aggregate, 7 parts of slow-release pre-coated fertilizer, 4 parts of soil-wrapped seed pellets, 12 parts of metakaolin-based polymer and 7 parts of water; the recycled coarse aggregate is treated by carbonation with CO2 gas, and the proportion of the recycled coarse aggregate is shown in Table 4, the target void ratio is 21%, and the apparent density is 2506 kg / m 3 , bulk density 1398kg / m 3 The comparison of recycled aggregate before and after carbonation is shown in Table 5.

[0051] Table 4 Recycled coarse aggregate gradation

[0052] Screen size mm 26.5 19 16 13.2 9.5 4.75 Pass Rate % 78 65 53 38 20 0

[0053] Table 5 Comparison of recycled coarse aggregate before and after carbonation

[0054] Recycled coarse aggregate Carbonated recycled coarse aggregate Porosity % 21.1 21.1 Compressive strengthMpa 12.7 15.2

[0055] The fine aggregate is red mud, with a porosity of 36% and a bulk density of 0.83 / cm 3 , pH value is 8.2.

[0056] The slow-release pre-coated fertilizer is composed of 5 parts of fertilizer and 2 parts of cementing material. The cementing material is gum arabic powder, and the fertilizer is ammonium sulfate solid particles. The fertilizer purity reaches 97.4%, the nitrogen content is 28%, and the water solubility rate is 94%.

[0057] The soil-wrapped seed pellets consist of 2 parts of soil and 2 parts of seeds. The soil is loess with a collapsibility coefficient of δs of 0.06, and the seeds are bermudagrass with a purity of 93%, a water content of 9.3%, and a germination rate of 98%.

[0058] The Al2O3 content of the metakaolin-based polymer is 38% by mass and the SiO2 content is 51% by mass.

[0059] The molar concentration of the activator potassium hydroxide solution is 2.5 mol / L.

[0060] The preparation method of the solid fertilizer moisturizing vegetation regeneration slope protection concrete comprises the following steps:

[0061] (1) crushing, screening, removing impurities, washing and drying concrete from dismantled abandoned buildings and bridges to obtain recycled coarse aggregate, taking 55 parts of the recycled coarse aggregate for carbonation treatment in a closed container, introducing carbon dioxide gas with a concentration of 35% for 16 hours, and controlling the reaction temperature at 25° C. to obtain carbonated recycled coarse aggregate;

[0062] (2) 13 parts of diatomaceous earth were taken and impurities were removed, and then water was retained for 3 hours to make its water absorption rate reach 110%, thereby obtaining water-absorbing fine aggregate;

[0063] (3) placing 5 parts of ammonium sulfate solid granular fertilizer into the bed of a fluidized bed coating machine, turning on the airflow to suspend the fertilizer solid particles in a fluidized state, and then dissolving 2 parts of gum arabic powder in water to obtain a solution, spraying the solution evenly on the fertilizer particles multiple times to form an elastic transparent coating layer on the surface of the fertilizer particles, thereby obtaining a slow-release pre-coated fertilizer;

[0064] (4) Put 2 parts of bermudagrass seeds and 2 parts of loess into a rotary pelletizer, spray water while rotating, and set the speed to 20 r / min to form a pellet structure during the uniform tumbling process, and collect soil-coated seed pellets with a diameter of 5-10 mm;

[0065] (5) 12 parts of kaolin are placed in a high temperature device and calcined at 700° C. for 3 h and dehydrated to obtain metakaolin, 2 parts of the activator solution are added to the metakaolin and stirred until a uniform paste-like mixture is formed to obtain a metakaolin-based polymer;

[0066] (6) The carbonated regenerated coarse aggregate obtained in step (1) was graded, with a target porosity of 21% and an actual porosity of 21.1%. 13 parts of red mud and fine aggregate obtained in step (2) were put into a stirring device and slowly stirred until a uniform mixture was obtained. The speed was set to 12 r / min and the stirring time was 40 s.

[0067] (7) 12 parts of the metakaolin-based polymer obtained in step (5) and the mixture obtained in step (6) are put into a mixing device, 7 parts of water are added for wet mixing, and the mixture is wet mixed at a speed of 25 r / min for 80 seconds. Then, 7 parts of the slow-release pre-coated fertilizer obtained in step (3) are added and stirred until a uniform concrete mixture is formed. Finally, 4 parts of the soil-coated seed pellets obtained in step (4) are added and stirred evenly to obtain a solid fertilizer, moisture-retaining, vegetation-regenerating slope protection concrete.

[0068] Similarly, the performance of the prepared solid fertilizer moisturizing vegetation regeneration slope protection concrete was tested, and the test results are shown in Table 6:

[0069] Table 6 Performance of concrete for slope protection with solid fertilizer, moisture retention and vegetation regeneration

[0070] Detection indicators Test results 28d compressive strength / MPa 16.8 28d flexural strength / MPa 3.6 pH 9.3 30d fertilizer residual nitrogen content% 17.8 Water permeability cm / s 0.33 Seed survival rate / % 92

[0071] Example 3

[0072] The solid fertilizer moisturizing vegetation regeneration slope protection concrete includes the following materials by mass: 65 parts of carbonated recycled coarse aggregate, 16 parts of fine aggregate, 8 parts of slow-release pre-coated fertilizer, 5 parts of soil-wrapped seed pellets, 15 parts of metakaolin-based polymer and 8 parts of water; the recycled coarse aggregate is carbonated with CO2 gas. The recycled coarse aggregate mix is ​​shown in Table 7, with a target void ratio of 24% and an apparent density of 2647 kg / m 3 , bulk density 1421kg / m 3 The comparison of recycled aggregate before and after carbonation is shown in Table 8:

[0073] Table 7 Recycled coarse aggregate gradation

[0074] Screen size mm 26.5 19 16 13.2 9.5 4.75 Pass Rate % 73 60 48 34 16 0

[0075] Table 8 Comparison of recycled coarse aggregate before and after carbonation

[0076] Recycled coarse aggregate Carbonated recycled coarse aggregate Porosity % 23.8 23.8 Compressive strengthMpa 12.2 15.4

[0077] The fine aggregate is red mud, with a porosity of 41% and a bulk density of 0.78 / cm 3 , pH value is 7.9.

[0078] The slow-release pre-coated fertilizer is composed of 6 parts of fertilizer and 2 parts of cementing material. The cementing material is gum arabic powder, and the fertilizer is potassium sulfate solid particles. The fertilizer purity reaches 98.3%, the K2O content is 43%, and the water solubility rate is 97%.

[0079] The soil-wrapped seed pellets consist of 2 parts of soil and 3 parts of seeds. The soil is silty clay with a collapsibility coefficient of δs of 0.07, and the seeds are Zoysia japonica with a purity of 95%, a water content of 10.6%, and a germination rate of 99%.

[0080] The Al2O3 content of the metakaolin-based polymer is 45% by mass and the SiO2 content is 49% by mass.

[0081] The molar concentration of the activator potassium hydroxide solution is 3 mol / L.

[0082] The preparation method of the solid fertilizer moisturizing vegetation regeneration slope protection concrete comprises the following steps:

[0083] (1) crushing, screening, removing impurities, washing and drying concrete from dismantled abandoned buildings and bridges to obtain recycled coarse aggregate, taking 65 parts of the recycled coarse aggregate for carbonation treatment in a closed container, introducing carbon dioxide gas with a concentration of 40% for 20 hours, and controlling the reaction temperature at 30° C. to obtain carbonated recycled coarse aggregate;

[0084] (2) 16 parts of diatomaceous earth are taken and impurities are removed, and then water is retained for 3 hours to make its water absorption rate reach 125%, thereby obtaining water-absorbing fine aggregate;

[0085] (3) placing 6 parts of potassium sulfate solid granular fertilizer into the bed of a fluidized bed coating machine, turning on the airflow to suspend the fertilizer solid particles in a fluidized state, and then dissolving 2 parts of gum arabic powder in water to obtain a solution, spraying the solution evenly on the fertilizer particles multiple times to form an elastic transparent coating layer on the surface of the fertilizer particles, thereby obtaining a slow-release pre-coated fertilizer;

[0086] (4) 3 parts of Zoysia seeds and 2 parts of silty clay were placed in a rotary pelletizer, and water was sprayed while rotating. The speed was set to 25 r / min, so that a pellet structure was formed during the uniform tumbling process, and qualified soil-coated seed pellets with a diameter of 5-10 mm were collected;

[0087] (5) 15 parts of kaolin are placed in a high temperature device and calcined at 800° C. for 3 h and dehydrated to obtain metakaolin, 2 parts of the activator solution are added to the metakaolin and stirred until a uniform paste-like mixture is formed to obtain a metakaolin-based polymer;

[0088] (6) The carbonated regenerated coarse aggregate obtained in step (1) is graded, the target porosity is 24%, and the measured porosity is 23.8%. 16 parts of red mud, the fine aggregate obtained in step (2), are put into a stirring device and stirred at a slow speed until a uniform mixture is obtained. The speed is set to 15 r / min and the stirring time is 50 s;

[0089] (7) 15 parts of the metakaolin-based polymer obtained in step (5) and the mixture obtained in step (6) are put into a mixing device, 8 parts of water are added for wet mixing, and wet mixing is performed at a speed of 25 r / min for 100 s. Then, 8 parts of the slow-release pre-coated fertilizer obtained in step (3) are added and stirred until a uniform concrete mixture is formed. Finally, 5 parts of the soil-coated seed pellets obtained in step (4) are added and stirred evenly to obtain a solid fertilizer, moisture-retaining, vegetation-regenerating slope protection concrete.

[0090] Similarly, the performance of the prepared solid fertilizer moisturizing vegetation regeneration slope protection concrete was tested, and the test results are shown in Table 9:

[0091] Table 9 Performance of concrete for slope protection with solid fertilizer, moisture retention and vegetation regeneration

[0092]

[0093]

[0094] Example 4

[0095] The solid fertilizer moisturizing vegetation regeneration slope protection concrete includes the following materials by mass: 70 parts of carbonated recycled coarse aggregate, 20 parts of fine aggregate, 10 parts of slow-release pre-coated fertilizer, 6 parts of soil-wrapped seed pellets, 20 parts of metakaolin-based polymer, and 10 parts of water; the recycled coarse aggregate is carbonated with CO2 gas; the recycled coarse aggregate mix ratio is shown in Table 10, the target void ratio is 28%, and the apparent density is 2733 kg / m 3 , bulk density 1421kg / m 3 The comparison of recycled aggregate before and after carbonation is shown in Table 11.

[0096] Table 10 Grading of recycled coarse aggregate

[0097] Screen size mm 26.5 19 16 13.2 9.5 4.75 Pass Rate % 69 56 44 30 12 0

[0098] Table 11 Comparison of recycled coarse aggregate before and after carbonation

[0099] Recycled coarse aggregate Carbonated recycled coarse aggregate Porosity % 27.9 27.9 Compressive strengthMpa 11.5 13.6

[0100] The fine aggregate is diatomaceous earth with a porosity of 89%, a bulk density of 0.45 / cm3 and a pH value of 6.5.

[0101] The slow-release pre-coated fertilizer is composed of 7 parts of fertilizer and 3 parts of cementing material. The cementing material is gum arabic powder, and the fertilizer is potassium sulfate solid particles. The fertilizer purity reaches 97.2%, the K2O content is 56%, and the water solubility rate is 98%.

[0102] The soil-wrapped seed pellets consist of 2 parts of soil and 4 parts of seeds. The soil is silty clay with a collapsibility coefficient of δs of 0.06, and the seeds are Zoysia japonica with a purity of 96%, a water content of 11%, and a germination rate of 97%.

[0103] The Al2O3 content of the metakaolin-based polymer is 40% by mass and the SiO2 content is 55% by mass.

[0104] The molar concentration of the activator potassium hydroxide solution is 4 mol / L

[0105] The preparation method of the solid fertilizer moisturizing vegetation regeneration slope protection concrete comprises the following steps:

[0106] (1) crushing, screening, removing impurities, washing and drying concrete from dismantled abandoned buildings and bridges to obtain recycled coarse aggregate, taking 70 parts of the recycled coarse aggregate for carbonation treatment in a closed container, introducing carbon dioxide gas with a concentration of 50% for 24 hours, and controlling the reaction temperature at 40° C. to obtain carbonated recycled coarse aggregate;

[0107] (2) taking 20 parts of diatomaceous earth and removing impurities, and retaining water for 4 hours, so that its water absorption rate reaches 185%, and obtaining water-absorbing fine aggregate;

[0108] (3) placing 7 parts of potassium sulfate solid granular fertilizer into the bed of a fluidized bed coating machine, turning on the airflow to suspend the fertilizer solid particles in a fluidized state, and then dissolving 3 parts of gum arabic powder in water to obtain a solution, spraying the solution evenly on the fertilizer particles multiple times to form an elastic transparent coating layer on the surface of the fertilizer particles, thereby obtaining a slow-release pre-coated fertilizer;

[0109] (4) putting 4 parts of Zoysia japonica seeds and 2 parts of silty clay into a rotary pelletizer, spraying water while rotating, setting the speed to 30 r / min, so that the pellet structure is formed during the uniform tumbling process, and collecting soil-coated seed pellets with a diameter of 5-10 mm;

[0110] (5) 20 parts of kaolin are placed in a high temperature device and calcined at 900° C. for 4 hours and dehydrated to obtain metakaolin, 3 parts of the activator solution are added to the metakaolin and stirred until a uniform paste mixture is formed to obtain a metakaolin-based polymer;

[0111] (6) The carbonated regenerated coarse aggregate obtained in step (1) is graded, the target porosity is 28%, and the measured porosity is 27.9%. 20 parts of diatomaceous earth obtained in step (2) are put into a stirring device and slowly stirred until a uniform mixture is obtained. The speed is set to 15 r / min and the stirring time is 60 s;

[0112] (7) 20 parts of the metakaolin-based polymer obtained in step (5) and the mixture obtained in step (6) are put into a mixing device, 10 parts of water are added for wet mixing, and the mixture is wet mixed at a speed of 30 r / min for 120 s. Then, 10 parts of the slow-release pre-coated fertilizer obtained in step (3) are added and stirred until a uniform concrete mixture is formed. Finally, 6 parts of the soil-coated seed pellets obtained in step (4) are added and stirred evenly to obtain a solid fertilizer, moisture-retaining, vegetation-regenerating slope protection concrete.

[0113] Similarly, the performance of the prepared solid fertilizer moisturizing vegetation regeneration slope protection concrete was tested, and the test results are shown in Table 12:

[0114] Table 12 Performance of concrete for slope protection with solid fertilizer, moisture retention and vegetation regeneration

[0115] Detection indicators Test results 28d compressive strength / MPa 15.2 28d flexural strength / MPa 3.5 pH 8.5 30d fertilizer residual potassium content% 31.4 Water permeability cm / s 0.45 Seed survival rate / % 91

[0116] Comparative Example 1

[0117] Comparative Example 1 is a comparative example of Example 1, except that the seeds were not treated with soil-wrapped pellets, and the other conditions and preparation processes were the same. The performance of the prepared solid fertilizer moisture-retaining vegetation regeneration slope protection concrete was tested, and the test results are shown in Table 13:

[0118] Table 13 Performance of concrete for slope protection with solid fertilizer, moisture retention and vegetation regeneration

[0119] Detection indicators Test results 28d compressive strength / MPa 18.1 28d flexural strength / MPa 3.5 pH 8.2 30d fertilizer residual nitrogen content% 14.7 Water permeability cm / s 0.45 Seed survival rate / % 79

[0120] Comparative Example 2

[0121] Comparative Example 2 is a comparative example of Example 2, except that solid particles of ammonium sulfate fertilizer are directly added, and the other conditions and preparation processes are the same. The performance of the prepared solid fertilizer moisturizing vegetation regeneration slope protection concrete was tested, and the test results are shown in Table 14:

[0122] Table 14 Performance of concrete for slope protection with solid fertilizer, moisture retention and vegetation regeneration

[0123] Detection indicators Test results 28d compressive strength / MPa 16.8 28d flexural strength / MPa 3.6 pH 9.1 30d fertilizer residual nitrogen content% 8.6 Water permeability cm / s 0.33 Seed survival rate / % 82

[0124] Comparative Example 3

[0125] Comparative Example 3 is a comparative example of Example 3, except that potassium sulfate fertilizer solid particles are directly added, and the other conditions and preparation processes are the same. The performance of the prepared solid fertilizer moisturizing vegetation regeneration slope protection concrete was tested, and the test results are shown in Table 15:

[0126] Table 15 Performance of concrete for slope protection with solid fertilizer, moisture retention and vegetation regeneration

[0127]

[0128]

[0129] It can be found that the solid fertilizer moisture-retaining vegetation regeneration slope protection concrete described in the present invention has good performances. Pre-coating the fertilizer solid particles and soil-coating the seeds can effectively improve the durability of the fertilizer and the survival rate of the seeds.

Claims

1. A solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete, characterized in that: The invention comprises the following materials in parts by weight: 50-70 parts of carbonated recycled coarse aggregate, 10-20 parts of fine aggregate, 5-10 parts of slow-release pre-coated fertilizer, 3-6 parts of soil-coated seed pellets, 10-20 parts of metakaolin-based polymer and 5-10 parts of water; the slow-release pre-coated fertilizer comprises 1-3 parts of cementitious material and 4-7 parts of fertilizer; the soil-coated seed pellets comprise 1-2 parts of soil and 2-4 parts of seeds; the carbonated recycled coarse aggregate is obtained by carbonation treatment of recycled coarse aggregate with CO2 gas.

2. The solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete according to claim 1 is characterized in that: The recycled coarse aggregate is obtained by crushing, screening, removing impurities, cleaning and drying concrete from abandoned buildings and bridges. The particle size is 4.75mm-26.5mm, the target void ratio is 18%-28%, and the apparent density is not less than 2300kg / m 3 , bulk density not less than 1200kg / m 3 .

3. The solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete according to claim 1 is characterized in that: The reaction time of the CO2 gas carbonation treatment is 12-24 hours, the CO2 gas concentration is 30%-50%, and the reaction temperature is 20-40°C.

4. The solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete according to claim 1 is characterized in that: The content of Al2O3 in the metakaolin-based polymer is 35%-45% by mass, and the content of SiO2 is 45%-55% by mass; the metakaolin-based polymer is obtained by reacting metakaolin with an activator, and the metakaolin is obtained by dehydrating kaolin by calcining it at a temperature of 600°C-900°C for 2-4h; the activator is a potassium hydroxide solution with a molar concentration of 2-4mol / L.

5. The solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete according to claim 1 is characterized in that: The fine aggregate is red mud or diatomaceous earth, and the water absorption rate is 100%-200%; the porosity of the red mud is 30%-50%, and the bulk density is 0.7-1.0g / cm 3 , pH value is 7-9; the porosity of the diatomaceous earth is 80%-90%, and the bulk density is 0.3-0.5g / cm 3 , pH value is 5-7.

6. The solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete according to claim 1 is characterized in that: The bonding material is gum arabic powder with a particle size of 100-200 μm.

7. The solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete according to claim 1 is characterized in that: The fertilizer is solid particles of ammonium sulfate or potassium sulfate, and the fertilizer purity reaches more than 95%; the nitrogen content of the solid particles of ammonium sulfate is 20%-30%; the K2O content of the solid particles of potassium sulfate is 40%-60% and the water solubility is greater than 90%.

8. The solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete according to claim 1 is characterized in that: The soil is loess or silty clay, and the soil collapsibility coefficient δs is greater than 0.

015.

9. The solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete according to claim 1 is characterized in that: The seeds include bermudagrass and zoysia grass, the purity of the seeds is more than 90%, the water content is between 7% and 12%, and the germination rate is greater than 90%.

10. A method for preparing the solid fertilizer, moisturizing, vegetation and regeneration slope protection concrete according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) placing the recycled coarse aggregate in a closed reaction container, and introducing CO2 gas into the container to obtain carbonated recycled coarse aggregate; (2) performing water-retaining treatment on the fine aggregate after screening and impurity removal to obtain water-absorbing fine aggregate; (3) placing solid fertilizer particles into a bed of a fluidized bed coating machine, turning on the airflow to suspend the solid fertilizer particles in a fluidized state, and then spraying the cementing material solution evenly on the solid fertilizer particles multiple times until an elastic transparent coating layer is formed on the surface of the solid fertilizer particles, thereby obtaining a slow-release pre-coated fertilizer; (4) placing seeds and soil into a rotary pelletizer, spraying water while rotating, so that the pellet structure is formed during the uniform tumbling process, and collecting soil-coated seed pellets with a diameter of 5-10 mm; (5) putting the carbonated regenerated coarse aggregate obtained in step (1) and the water-absorbing fine aggregate obtained in step (2) into a stirring device for stirring to obtain a uniform mixture; (6) Putting the metakaolin-based polymer and the mixture obtained in step (5) into a stirring device, adding water for wet mixing, then adding the slow-release pre-coated fertilizer obtained in step (3) until a uniform mixture is formed, and finally adding the soil-wrapped seed pellets obtained in step (4), and uniformly stirring to obtain a fertilizer-solidifying, moisture-retaining, vegetation-growing, and regenerating slope protection concrete.

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