Fertilizer-retaining and moisture-retaining vegetation-regenerating slope-protection concrete and preparation method thereof

Abstract

The application discloses a kind of solid fertilizer moisture conservation plant growth regeneration slope protection concrete and preparation method thereof, including the following mass fraction of materials: carbonation recycled coarse aggregate 50-70 parts, fine aggregate 10-20 parts, slow-release pre-coated fertilizer 5-10 parts, soil-coated seed pellet 3-6 parts, metakaolin-based polymer 10-20 parts and water 5-10 parts;The slow-release pre-coated fertilizer includes cementing material 1-3 parts and fertilizer 4-7 parts;The soil-coated seed pellet includes soil 1-2 parts and seed 2-4 parts;The carbonation recycled coarse aggregate is obtained by CO2 gas carbonation treatment from recycled coarse aggregate.The application can realize the recycling of waste concrete resources, and alleviate the problem of land occupation;With metakaolin-based polymer instead of traditional cement material, the preparation process is simple, which can reduce energy consumption and environmental pollution;Effectively resist water scouring, ensure fertilizer efficacy, conducive to seed germination, enhance the stability of slope protection;Increase vegetation coverage, improve landscape quality.

Description

TECHNICAL FIELD

[0001] The application belongs to building materials and a preparation method thereof, and particularly relates to a solid-fertilizer-moisture-retaining plant-growing regenerative slope-protection concrete and a preparation method thereof. BACKGROUND

[0002] In highway and waterway engineering, if the slope body loses the stability of the slope protection engineering, local or large-area collapse may occur, causing a large number of casualties and property losses. Under the action of natural forces such as rainwater erosion and wind erosion, the loss of soil and sediment on the slope surface causes river channel siltation, increases the risk of flood disasters, and destroys the ecological balance of the region.

[0003] CN111517707A discloses an ecological slope-protection concrete and a construction method thereof, and grass seeds are placed in the surface layer concrete; CN117819935A discloses a design method of a regenerative aggregate type plant-growing concrete based on magnesium phosphate cement, the plant roots grown in the existing slope-protection concrete are shallow, the water flow erosion resistance is weak, and the fertilizer cannot be released continuously to provide nutrients for plant growth, resulting in plant death; at the same time, the existing slope-protection concrete still relies on the use of cement materials, and there is no technical solution for completely replacing traditional cement materials with metakaolin-based polymers for preparing plant-growing regenerative slope-protection concrete. SUMMARY

[0004] The purpose of the present application is to provide a plant-growing regenerative slope-protection concrete which utilizes waste concrete resources, is beneficial to seed rooting and germination, and realizes solid fertilizer moisture retention and erosion resistance; another purpose of the present application is to provide a preparation method of the solid fertilizer moisture-retaining plant-growing regenerative slope-protection concrete.

[0005] The technical solution of the present application is a solid fertilizer moisture-retaining plant-growing regenerative slope-protection concrete, which comprises the following materials in mass fractions: carbonated recycled coarse aggregate 50-70 parts, fine aggregate 10-20 parts, slow-release pre-coated fertilizer 5-10 parts, soil-coated seed pellets 3-6 parts, metakaolin-based polymer 10-20 parts, and water 5-10 parts; the slow-release pre-coated fertilizer comprises cementing material 1-3 parts and fertilizer 4-7 parts; the soil-coated seed pellets comprise soil 1-2 parts and seeds 2-4 parts; the carbonated recycled coarse aggregate is obtained by carbonating recycled coarse aggregate with CO2 gas.

[0006] Further, the recycled coarse aggregate is obtained by crushing, screening, impurity removal, washing and drying of waste concrete from demolished buildings and bridges, has a particle size of 4.75mm-26.5mm, a target void ratio of 18%-28%, and an apparent density of not less than 2300kg / m 3 , and a bulk density of not less than 1200kg / m 3 .

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

[0008] Further, 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 at a temperature of 600-900℃ for 2-4h; and the activator is a potassium hydroxide solution with a molar concentration of 2-4mol / L.

[0009] Further, the fine aggregate is red mud or diatomite, 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 , and the pH value is 7-9; the porosity of the diatomite is 80%-90%, the bulk density is 0.3-0.5g / cm 3 , and the pH value is 5-7.

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

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

[0012] Further, the soil is loess or silty clay, and the soil has a collapsibility δs greater than 0.015.

[0013] Further, the seeds include centipede grass and St. Augustine grass, and the purity of the seeds is more than 90%, the water content is between 7%-12%, and the germination rate is greater than 90%.

[0014] The preparation method of the solid fertilizer moisture-retaining vegetation regeneration slope protection concrete provided by the application comprises the following steps:

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

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

[0017] (3) placing the solid fertilizer particles in the bed body of a fluidized bed coating machine, starting the airflow to make the solid fertilizer particles suspended in a fluidized state, and repeatedly and uniformly spraying the cementing material solution on the solid fertilizer particles until an elastic transparent coating layer is formed on the surface of the solid fertilizer particles to obtain slow-release pre-coated fertilizer;

[0018] (4) Put the seeds and soil into a rotary pelletizer, spray water while rotating, and form the pellet structure in the process of uniform tumbling, and collect the soil-coated seed pellets with a diameter of 5-10 mm;

[0019] (5) Put the carbonated recycled coarse aggregate obtained in step (1) and the water-absorbing fine aggregate obtained in step (2) into a stirring device to obtain a uniformly mixed material;

[0020] (6) Put the metakaolin-based polymer and the mixed material obtained in step (5) into a stirring device to wet mix with water, then add the slow-release pre-coated fertilizer obtained in step (3), until a uniform mixture is formed, and finally add the soil-coated seed pellets obtained in step (4), and uniformly stir to obtain the solid fertilizer moisture-retaining plant-growing regenerated slope protection concrete.

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

[0022] 1. The waste concrete resources are recycled, and the land occupation problem of building solid waste is alleviated; the metakaolin-based polymer is used instead of traditional cement materials, the preparation process is simple and easy to implement, the energy consumption can be reduced, and the environmental pollution can be reduced;

[0023] 2. The water permeability is enhanced, the water and soil loss is reduced, the water flow erosion is effectively resisted, the fertilizer effectiveness is ensured, the seed germination is facilitated, and the stability of the slope protection is enhanced;

[0024] 3. The slope vegetation coverage is increased, a stable ecological system is formed, and the landscape quality is improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a preparation method flowchart of the present application. DETAILED DESCRIPTION

[0026] In the following examples, the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels. The experimental methods not specified in the examples are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturer.

[0027] Example 1

[0028] The solid fertilizer moisture-retaining plant-growing regenerated slope protection concrete comprises the following materials in parts by mass: carbonated recycled coarse aggregate 50 parts, fine aggregate 10 parts, slow-release pre-coated fertilizer 5 parts, soil-coated seed pellets 3 parts, metakaolin-based polymer 10 parts, and water 5 parts; the recycled coarse aggregate is treated by CO2 gas carbonation; 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 The bulk density is 1365 kg / m 3， The comparison before and after carbonation of the recycled aggregate is shown in Table 2.

[0029] Table 1 recycled coarse aggregate gradation

[0030] Mesh 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 strength Mpa 13.1 15.8

[0033] Fine aggregate is diatomite, porosity 85%, bulk density 0.36 / cm 3 , pH value is 5.3.

[0034] 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, with a purity of 95.3%, a nitrogen content of 24%, and a water solubility of 91%.

[0035] Soil-coated seed pellets are composed of 1 part of soil and 2 parts of seeds. The soil is loess with a collapse coefficient δs of 0.03, and the seeds are dogtooth grass with a purity of 96%, a water content of 7.8%, and a germination rate of 98%.

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

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

[0038] The preparation method of the solid fertilizer moisture-retaining plant-growing slope protection concrete comprises the following steps:

[0039] (1) The waste concrete from building and bridge demolition is crushed, screened, impurity-removed, washed and dried to obtain recycled coarse aggregate. 50 parts of the recycled coarse aggregate are subjected to carbonation treatment in a sealed container, and carbon dioxide gas with a concentration of 30% is introduced for 12 hours. The reaction temperature is controlled at 20°C to obtain carbonated recycled coarse aggregate;

[0040] (2) 10 parts of diatomite are impurity-removed and water-retained for 2 hours to make the water absorption rate reach 160%, thereby obtaining water-absorbing fine aggregate;

[0041] (3) 4 parts of ammonium sulfate solid particle fertilizer are placed in the bed body of a fluidized bed coating machine, and the airflow is turned on to make the fertilizer solid particles suspended in a fluidized state. Then, 1 part of gum arabic powder is dissolved in water to obtain a dissolution solution, which is uniformly sprayed on the fertilizer particles multiple times to form an elastic and transparent coating layer on the surface of the fertilizer particles, thereby obtaining slow-release pre-coated fertilizer;

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

[0043] (5) Put 10 parts of kaolin into a high-temperature device for calcination at a temperature of 600°C for 2 h and dehydration treatment to obtain metakaolin, add 1 part of the activator solution to the metakaolin and stir until a uniform paste mixture is formed to obtain the metakaolin base polymer;

[0044] (6) Perform gradation design on the carbonated recycled coarse aggregate obtained in step (1), the target air void is 19%, the measured porosity is 18.6%, take 10 parts of the fine aggregate obtained in step (2) and put them into a stirring device for slow stirring until a uniform mixture is obtained, set the rotating speed to 10 r / min, and the stirring time is 30 s;

[0045] (7) Take 10 parts of the metakaolin base polymer obtained in step (5) and the mixture obtained in step (6) and put them into a stirring device for wet mixing with 5 parts of water, wet mix at a rotating speed of 20 r / min for 60 s, then add 4 parts of the slow-release pre-coated fertilizer obtained in step (3) and stir until a uniform concrete mixture is formed, finally add 3 parts of the soil-coated seed pellets obtained in step (4) and uniformly stir to obtain the solid fertilizer moisture-retaining plant regenerative slope protection concrete.

[0046] Test the performance of the prepared solid fertilizer moisture-retaining plant regenerative slope protection concrete, cast 150 mm*150 mm*150 mm standard test pieces, and test the 28 d compressive strength, 28 d flexural strength, pH value, 30 d residual nitrogen content of the fertilizer, water permeability coefficient and seed survival rate. The test results are shown in Table 3:

[0047] Table 3 Performance of solid fertilizer moisture-retaining plant regenerative slope protection concrete

[0048] Test index Test result 28d compressive strength / MPa 18.1 28d flexural strength / MPa 3.5 pH value 8.1 30d fertilizer residual nitrogen content % 14.5 Permeability coefficient cm / s 0.46 Seed survival rate % 94

[0049] Example 2

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

[0051] Table 4 Gradation of recycled coarse aggregate

[0052] Mesh 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 strength Mpa 12.7 15.2

[0055] Fine aggregate is red mud, porosity is 36%, bulk density is 0.83 / cm 3 , pH value is 8.2.

[0056] 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, with purity of 97.4%, nitrogen content of 28%, and water solubility of 94%.

[0057] Soil-coated seed pellets are composed of 2 parts of soil and 2 parts of seeds. The soil is loess with a collapse coefficient δs of 0.06, and the seeds are dog teeth, with a purity of 93%, a water content of 9.3%, and a germination rate of 98%.

[0058] The Al2O3 content in the metakaolin-based geopolymer is 38% by mass, and the SiO2 content is 51%.

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

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

[0061] (1) The waste building and bridge demolition concrete is crushed, screened, impurity removed, washed and dried to obtain recycled coarse aggregate. 55 parts of recycled coarse aggregate are carbonated in a sealed container, and 35% carbon dioxide gas is introduced for 16 hours, with the reaction temperature controlled at 25°C, to obtain carbonated recycled coarse aggregate;

[0062] (2) 13 parts of diatomite are impurity removed and water retained for 3 hours to make the water absorption rate reach 110%, to obtain water absorption fine aggregate;

[0063] (3) 5 parts of ammonium sulfate solid particle fertilizer are placed in the bed body of the fluidized bed coating machine, and the airflow is turned on to make the fertilizer solid particles suspended in a fluidized state. Then 2 parts of gum arabic powder are dissolved in water to obtain a dissolution solution, which is sprayed on the fertilizer particles several times to form a transparent coating layer with elasticity on the surface of the fertilizer particles, to obtain slow-release pre-coated fertilizer;

[0064] (4) 2 parts of dog tooth seeds and 2 parts of loess are put into a rotary pelletizer, and water is sprayed while rotating at a speed of 20 r / min, so that the pellet structure is formed in the process of uniform tumbling, and soil-coated seed pellets with a diameter of 5-10 mm are collected;

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

[0066] (6) The carbonated recycled coarse aggregate obtained in step (1) is graded to have a target void ratio of 21%, and the measured porosity is 21.1%. 13 parts of the fine aggregate of red mud obtained in step (2) is added to a stirring device and stirred slowly until a uniform mixture is obtained, with a stirring speed of 12 r / min and a stirring time of 40 s;

[0067] (7) 12 parts of the metakaolin base polymer obtained in step (5) and the mixture obtained in step (6) are added to a stirring device and wet mixed with 7 parts of water, with a wet mixing speed of 25 r / min and a wet mixing time of 80 s. Then 7 parts of the slow-release pre-coated fertilizer obtained in step (3) is added and stirred until a uniform concrete mixture is formed. Finally, 4 parts of the soil-coated seed pellets obtained in step (4) is uniformly stirred to obtain the solid fertilizer moisture-retaining plant growth regenerative slope protection concrete.

[0068] Similarly, the performance of the prepared solid fertilizer moisture-retaining plant growth regenerative slope protection concrete is detected, and the detection results are shown in Table 6:

[0069] Table 6 Performance of solid fertilizer moisture-retaining plant growth regenerative slope protection concrete

[0070] Test index Test result 28d compressive strength / MPa 16.8 28d flexural strength / MPa 3.6 pH value 9.3 30d fertilizer residual nitrogen content % 17.8 Permeability coefficient cm / s 0.33 Seed survival rate % 92

[0071] Example 3

[0072] The solid fertilizer moisture-retaining plant growth regenerative slope protection concrete comprises the following materials in mass parts: carbonated recycled coarse aggregate 65 parts, fine aggregate 16 parts, slow-release pre-coated fertilizer 8 parts, soil-coated seed pellets 5 parts, metakaolin base polymer 15 parts, and water 8 parts. The recycled coarse aggregate is treated by CO2 gas carbonation. The mix proportion of the recycled coarse aggregate is shown in Table 7, and the target void ratio is 24%, and the apparent density is 2647 kg / m 3 , and the bulk density is 1421 kg / m 3 . The comparison before and after carbonation of the recycled aggregate is shown in Table 8:

[0073] Table 7 Grading of recycled coarse aggregate

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

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

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

[0077] Fine aggregate is red mud, porosity is 41%, bulk density is 0.78 / cm 3 , pH value is 7.9.

[0078] 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, with purity of 98.3%, K2O content of 43%, and water solubility of 97%.

[0079] Soil-coated seed pellets are composed of 2 parts of soil and 3 parts of seeds. The soil is silty clay with a collapse coefficient δs of 0.07, and the seeds are St. Augustine grass with a purity of 95%, a water content of 10.6%, and a germination rate of 99%.

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

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

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

[0083] (1) The waste building and bridge demolition concrete is crushed, screened, impurity-removed, washed and dried to obtain recycled coarse aggregate. 65 parts of recycled coarse aggregate are subjected to carbonation treatment in a sealed container, and carbon dioxide gas with a concentration of 40% is introduced for 20 hours. The reaction temperature is controlled at 30°C to obtain carbonated recycled coarse aggregate.

[0084] (2) 16 parts of diatomite are impurity-removed and water-retained for 3 hours to make the water absorption rate reach 125%, thereby obtaining water-absorbing fine aggregate.

[0085] (3) 6 parts of potassium sulfate solid particle fertilizer are placed in the bed body of a fluidized bed wrapping machine, and the airflow is turned on to make the fertilizer solid particles suspended in a fluidized state. Then, 2 parts of gum arabic powder are dissolved in water to obtain a dissolution solution, which is sprayed on the fertilizer particles multiple times to form a transparent wrapping layer with elasticity on the surface of the fertilizer particles, thereby obtaining slow-release pre-coated fertilizer.

[0086] (4) 3 parts of St. Augustine grass seeds and 2 parts of silty clay are placed in a rotary pelletizer, and water is sprayed while rotating at a speed of 25 r / min to form pellet structure in the process of uniform tumbling. The qualified soil-coated seed pellets with a diameter of 5-10 mm are collected.

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

[0088] (6) The carbonated recycled coarse aggregate obtained in step (1) is graded with a target void ratio of 24% and a measured porosity of 23.8%. The fine aggregate obtained in step (2) is added to the stirring device at a rate of 16 parts, and the mixture is slowly stirred until a uniform mixture is obtained. The stirring speed is set to 15 r / min, and the stirring time is 50 s;

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

[0090] Similarly, the properties of the prepared solid-fertilizer-moisture-retaining plant-growing slope-protection concrete are detected, and the detection results are shown in Table 9:

[0091] Table 9 Properties of solid-fertilizer-moisture-retaining plant-growing slope-protection concrete

[0092]

[0093]

[0094] Example 4

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

[0096] Table 10 Gradation of recycled coarse aggregate

[0097] Mesh 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 strength Mpa 11.5 13.6

[0100] The fine aggregate is diatomite, 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 purity of the fertilizer reaches 97.2%, the K2O content is 56%, and the water solubility rate is 98%.

[0102] The soil-coated seed pellet is composed of 2 parts of soil and 4 parts of seed. The soil is silty clay with a collapsibility coefficient δs of 0.06, and the seed is St. Augustine grass with a purity of 96%, a water content of 11%, and a germination rate of 97%.

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

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

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

[0106] (1) The waste concrete from building and bridge demolition is crushed, screened, impurity-removed, washed, and dried to obtain recycled coarse aggregate. 70 parts of the recycled coarse aggregate are subjected to carbonation treatment in a sealed container by introducing carbon dioxide gas with a concentration of 50% for 24 h at a reaction temperature of 40°C to obtain carbonated recycled coarse aggregate.

[0107] (2) 20 parts of diatomite are impurity-removed and water-retained for 4 h to make the water absorption rate reach 185% to obtain water-absorbing fine aggregate.

[0108] (3) 7 parts of potassium sulfate solid particle fertilizer are placed in the bed body of a fluidized bed wrapping machine, and the airflow is turned on to make the fertilizer solid particles suspended in a fluidized state. Then, 3 parts of gum arabic powder are dissolved in water to obtain a dissolution solution, which is sprayed on the fertilizer particles multiple times to form an elastic and transparent wrapping layer on the surface of the fertilizer particles, thereby obtaining slow-release pre-coated fertilizer.

[0109] (4) 4 parts of St. Augustine grass seed and 2 parts of silty clay are placed in a rotary pelletizer, and water is sprayed while rotating at a speed of 30 r / min to form a pellet structure in the process of uniform tumbling. The soil-coated seed pellets with a diameter of 5-10 mm are collected.

[0110] (5) 20 parts of kaolin are calcined at a temperature of 900°C for 4 h and dehydrated to obtain metakaolin. Then, 3 parts of activator solution are added to the metakaolin and stirred until a uniform paste-like mixture is formed, thereby obtaining metakaolin-based polymer.

[0111] (6) The carbonated recycled coarse aggregate obtained in step (1) is graded with a target void ratio of 28% and a measured porosity of 27.9%. The fine aggregate obtained in step (2) is added to the stirring device together with 20 parts of diatomite, and slow stirring is performed until a uniform mixture is obtained, at a speed of 15 r / min and a stirring time of 60 s;

[0112] (7) The metakaolin-based polymer obtained in step (5) is added to the stirring device together with the mixture obtained in step (6), 10 parts of water is added for wet mixing, and wet mixing is performed at a speed of 30 r / min for 120 s. Then, the slow-release pre-coated fertilizer obtained in step (3) is added for stirring, until a uniform concrete mixture is formed. Finally, the soil-coated seed pellets obtained in step (4) are added for uniform stirring, to obtain the solid-fertilizer-moisture-retaining plant-growing slope-regeneration concrete.

[0113] Similarly, the properties of the prepared solid-fertilizer-moisture-retaining plant-growing slope-regeneration concrete are detected, and the detection results are shown in Table 12:

[0114] Table 12 Properties of solid-fertilizer-moisture-retaining plant-growing slope-regeneration concrete

[0115] Test index Test result 28d compressive strength / MPa 15.2 28d flexural strength / MPa 3.5 pH value 8.5 30d fertilizer residual potassium content % 31.4 Permeability coefficient 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 are not subjected to soil-coated pellet treatment, and the rest of the conditions and preparation processes are the same. The properties of the prepared solid-fertilizer-moisture-retaining plant-growing slope-regeneration concrete are detected, and the detection results are shown in Table 13:

[0118] Table 13 Properties of solid-fertilizer-moisture-retaining plant-growing slope-regeneration concrete

[0119] Test index Test result 28d compressive strength / MPa 18.1 28d flexural strength / MPa 3.5 pH value 8.2 30d fertilizer residual nitrogen content % 14.7 Permeability coefficient 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 the solid particles of ammonium sulfate fertilizer are directly added, and the rest of the conditions and preparation processes are the same. The properties of the prepared solid-fertilizer-moisture-retaining plant-growing slope-regeneration concrete are detected, and the detection results are shown in Table 14:

[0122] Table 14 Properties of solid-fertilizer-moisture-retaining plant-growing slope-regeneration concrete

[0123] Test index Test result 28d compressive strength / MPa 16.8 28d flexural strength / MPa 3.6 pH value 9.1 30d fertilizer residual nitrogen content % 8.6 Permeability coefficient cm / s 0.33 Seed survival rate % Test index Test result 28d compressive strength / MPa 28d flexural strength / MPa pH value 30d fertilizer residual nitrogen content % Permeability coefficient cm / s Seed survival rate % 82

[0124] Comparative Example 3

[0125] Comparative Example 3 is a comparative example of Example 3, except that the potassium sulfate fertilizer solid particles are directly added, and the rest of the conditions and preparation processes are the same. The performance of the prepared solid fertilizer moisture-retaining plant regeneration slope protection concrete is detected, and the detection results are shown in Table 15:

[0126] Table 15 Performance of solid fertilizer moisture-retaining plant regeneration slope protection concrete

[0127]

[0128]

[0129] It can be found that the solid fertilizer moisture-retaining plant regeneration slope protection concrete has good performance, and the pre-coating treatment of the fertilizer solid particles and the soil-coated pellet treatment of the seeds can effectively improve the persistence of the fertilizer and the survival rate of the seeds.

Claims

1. A solid fertilizer-moisture-retaining vegetation regenerative slope protection concrete, characterized by, The application relates to a solid-fertilizer-moisture-planting regenerative slope protection concrete, which comprises the following materials in mass fraction: carbonated recycled coarse aggregate 50-70 parts, fine aggregate 10-20 parts, slow-release pre-coated fertilizer 5-10 parts, soil-coated seed pellet 3-6 parts, metakaolin base polymer 10-20 parts and water 5-10 parts; the slow-release pre-coated fertilizer is composed of 1-3 parts of cementing material and 4-7 parts of fertilizer, wherein the cementing material is gum arabic powder; the soil-coated seed pellet comprises soil 1-2 parts and seed 2-4 parts, and the diameter of the soil-coated seed pellet is 5-10 mm; the carbonated recycled coarse aggregate is obtained by treating recycled coarse aggregate with CO2 gas; the fertilizer is ammonium sulfate or potassium sulfate solid particle, and the purity of the fertilizer is higher than 95%; the nitrogen content of the ammonium sulfate solid particle is 20%-30%; the K2O content of the potassium sulfate solid particle is 40%-60%, and the water solubility is higher than 90%.

2. The solid fertilizer-moisture retaining vegetation regenerating slope protection concrete according to claim 1, characterized in that, The recycled coarse aggregate is obtained by crushing, screening, removing impurities, cleaning and drying the concrete from waste buildings and bridge demolitions, 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 , and the bulk density is not less than 1200kg / m 3 .

3. The solid fertilizer-moisture retaining vegetation regenerating slope protection concrete according to claim 1, characterized in that, The reaction time of the CO2 gas carbonation treatment is 12-24 h, the CO2 gas concentration is 30%-50%, and the reaction temperature is 20-40 DEG C.

4. The fertilized and moisture-protected vegetation regenerating revetment concrete according to claim 1, characterized in that, In the metakaolin base polymer, the content of Al2O3 is 35%-45% by mass, and the content of SiO2 is 45%-55% by mass; the metakaolin base polymer is obtained by reacting metakaolin with an activator, wherein the metakaolin is obtained by calcining kaolin at a temperature of 600 DEG C-900 DEG C for 2-4 h to remove water; and the activator is potassium hydroxide solution with a molar concentration of 2-4 mol / L.

5. The fertilized and moisture-protected vegetation regenerating revetment concrete according to claim 1, characterized in that, The fine aggregate is red mud or diatomite, the water absorption is 100%-200%; the porosity of the red mud is 30%-50%, the bulk density is 0.7-1.0g / cm 3 , the pH value is 7-9; the porosity of the diatomite is 80%-90%, the bulk density is 0.3-0.5g / cm 3 , the pH value is 5-7.

6. The fertilized and moisture-protected vegetation regenerating revetment concrete according to claim 1, characterized in that, The particle size of the gum arabic powder is 100-200 mu m.

7. The fertilized and moisture-protected vegetation regenerating revetment concrete according to claim 1, characterized in that, The soil is loess or silty clay, and the collapsibility coefficient of the soil is greater than 0.

015.

8. The fertilized and moisture-protected vegetation regenerating revetment concrete according to claim 1, characterized in that, The seed comprises dog tooth grass and centipede grass, and the purity of the seed is higher than 90%, the water content is between 7% and 12%, and the germination rate is higher than 90%.

9. A method for preparing the solid fertilizer-moisture retaining vegetation regenerative revetment concrete according to any one of claims 1 to 8, characterized in that, The application further discloses a preparation method of the solid-fertilizer-moisture-planting regenerative slope protection concrete. (1) placing recycled coarse aggregate in a closed reaction container, and introducing CO2 gas into the container to obtain carbonated recycled coarse aggregate; (2) performing water-retention treatment on fine aggregate after screening and impurity removal to obtain water-absorbing fine aggregate; (3) placing solid fertilizer particles in the bed body of a fluidized bed coating machine, starting airflow to make the solid fertilizer particles float in a fluidized state, and spraying cementing material solution on the solid fertilizer particles for multiple times until an elastic transparent coating layer is formed on the surface of the solid fertilizer particles to obtain slow-release pre-coated fertilizer; (4) placing seed and soil into a rotary pelletizer, spraying water while rotating, and collecting soil-coated seed pellets with a diameter of 5-10 mm; (5) putting the carbonated recycled coarse aggregate obtained in the step (1) and the water-absorbing fine aggregate obtained in the step (2) into a stirring device to obtain uniformly mixed materials; (6) putting metakaolin base polymer and the mixed materials obtained in the step (5) into a stirring device to perform wet mixing after adding water, then adding the slow-release pre-coated fertilizer obtained in the step (3), and finally adding the soil-coated seed pellets obtained in the step (4) to obtain solid-fertilizer-moisture-planting regenerative slope protection concrete.

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