Grass seed double-shell microsphere suitable for vegetated concrete, preparation method and application

Abstract

The present invention discloses a grass seed double-shell microsphere suitable for vegetation concrete, a preparation method and an application. The grass seed is initially wrapped by the cross-linking effect of sodium alginate and a curing agent to obtain grass seed microspheres, and then the grass seed is secondary wrapped by sulfoaluminate-gypsum to form grass seed double-shell microspheres. At the same time, the microspheres also contain nutrients to protect the grass seed from external invasions while ensuring a normal living environment for the grass seed. When the prepared grass seed double-shell microspheres are used in conjunction with vegetation concrete, the double-shell structure can help the grass seed resist the alkaline environment inside the vegetation concrete, reduce the negative impact on the growth of the grass seed, and promote the germination and growth of the grass seed in the vegetation concrete, thereby achieving ecological protection of the slope without changing the properties of the vegetation concrete itself, and reducing the requirements for the raw materials and preparation method of the vegetation concrete. The preparation process of the present invention is simple, the raw materials are easily available, the applicability is wide, and it is easy to promote and apply on a large scale.

Description

Technical Field

[0001] The present invention belongs to the technical field of slope protection, and in particular relates to a grass seed double-shell microsphere suitable for vegetation concrete, a preparation method and an application thereof. Background Art

[0002] Vegetative concrete, also known as ecological concrete, green concrete, or vegetated concrete, is a new type of slope protection material that effectively combines engineering protection with ecological restoration. Composed solely of coarse aggregate, a binder, and admixtures, it relies on the cementing action of the binder, which works in conjunction with the coarse aggregate to form a cohesive whole. This new, environmentally friendly product boasts high strength and a unique structure, demonstrating its ecological benefits. The unique pore structure within vegetative concrete allows plant roots to enter the concrete, ensuring space for plant growth. This achieves the goals of soil consolidation, slope protection, and landscaping, achieving a perfect combination of hardened concrete and green vegetation. It is an excellent ecological slope protection technology.

[0003] Since the hydration reaction in the raw materials easily produces alkaline substances, the interior of the vegetation concrete is alkaline. This makes it difficult for the grass seeds to germinate and grow, whether they are directly mixed in the vegetation concrete or sown after forming, and thus it is difficult to achieve the effect of greening and beautifying the mountain, which seriously limits its promotion and application. At present, the main method to solve this problem is to reduce the alkalinity of the vegetation concrete, such as adding other substances to the vegetation concrete to reduce the alkalinity or spraying acidic substances on the surface after the concrete is laid. Chinese patent CN114751693B discloses a protective low-alkali vegetation concrete and its preparation method, which sprays oxalic acid solution on the surface of the prepared concrete specimen to reduce the alkali; Chinese patent CN101538135B discloses a vegetation-type porous concrete and its preparation method, which adopts the addition of concrete alkaline regulator to reduce the alkalinity to make it suitable for plant growth. CN107935625B discloses a low-alkalinity vegetative porous concrete, in which silicon dioxide is introduced into the raw materials so that silicon dioxide can react with alkaline substances produced by cement hydration reaction to reduce alkalinity.

[0004] In order to ensure that the mechanical properties of the vegetation concrete do not decrease while reducing the alkalinity inside, it is often necessary to add other substances to enhance the mechanical properties. This not only increases the cost, but also increases the difficulty of preparing the vegetation concrete. Therefore, it is not suitable for large-scale application and promotion. Spraying acidic substances after the vegetation concrete is formed involves maintenance issues. At the same time, when acidic substances enter an environment that does not contain vegetation concrete, they are also likely to destroy the acid-base balance of other environments. Therefore, its application is greatly limited. The vegetation bag slope protection technology currently used on the slopes of reservoirs, rivers, etc. has the disadvantages that the vegetation bags are not resistant to erosion by water flow and water level fluctuations, are not easy to anchor, and the plants in the vegetation bags are difficult to survive after the planting soil in the vegetation bags is lost. Therefore, it is difficult to apply it on a large scale. Summary of the Invention

[0005] In response to the above technical problems, the present invention provides a preparation method and application of grass seed double-shell microspheres suitable for vegetation concrete. By embedding grass seeds in microspheres with a double-shell structure, the grass seeds can be directly mixed into the vegetation concrete or sprayed and planted after they are formed. The survival rate of the grass seeds is guaranteed without changing the vegetation concrete, so that they are not interfered with by the alkaline substances inside the vegetation concrete.

[0006] The present invention adopts the following technical solution:

[0007] A grass seed double-shell microsphere suitable for vegetated concrete comprises 25-35 parts of grass seeds, 1-15 parts of nutrients, 1-10 parts of sodium alginate, 5-10 parts of emulsifier, 5-15 parts of curing agent, 1-2 parts of sulphoaluminate and 1-8 parts of gypsum.

[0008] Preferably, the grass species are one or more of foxtail grass, bluegrass, alfalfa, bermudagrass, sparsely flowered water hyacinth, zoysia grass and blunt-leaved grass.

[0009] Preferably, the nutrient is a mixture of coffee grounds and seaweed bio-fertilizer, wherein the mass ratio of coffee grounds to seaweed bio-fertilizer is 1:8-1:2.

[0010] Preferably, the emulsifier is Tween-80 or Span-80.

[0011] Preferably, the curing agent is any one of calcium nitrate, calcium lactate or aluminum nitrate.

[0012] The present invention also provides a method for preparing grass seed double-shell microspheres, which specifically comprises the following steps:

[0013] (1) Mixing grass seeds, sodium alginate, nutrients and emulsifier in proportion, and adding deionized water to prepare a grass seed mixed solution;

[0014] (2) preparing a curing agent into a curing agent saturated solution; preparing a sulphoaluminate-gypsum mixed solution;

[0015] (3) adding the grass seed mixture dropwise to a saturated solution of a curing agent and curing for 3-6 hours, and drying the resulting grass seed microspheres;

[0016] (4) Adding the grass seed microspheres into the sulphoaluminate-gypsum mixture, stirring and mixing, filtering and drying to obtain the grass seed double-shell microspheres.

[0017] Preferably, the drying in step (3) and step (4) is air drying for 12-72 hours or vacuum drying at 20-40°C for 8-12 hours.

[0018] Preferably, the diameter of the grass seed double-shell microspheres in step (4) is 1.5-3.0 mm, and the number of grass seeds in the grass seed double-shell microspheres is 500-1000.

[0019] The present invention also provides an application of grass seed double-shell microspheres in slope protection.

[0020] Preferably, the slope protection material is vegetated concrete.

[0021] The beneficial effects of the present invention are as follows: sodium alginate is cross-linked with a curing agent to form a gel-like substance, which can be used as an outer shell to wrap grass seeds to form microspheres with a core-shell structure. At the same time, the sodium alginate gel is water-absorbent. When environmental conditions are met, it will provide moisture to the grass seeds contained therein, thereby promoting the germination and survival of the grass seeds. The surface of the sodium alginate gel has pores, which also provide necessary air for the survival of the grass seeds. In combination with nutrients such as coffee grounds and seaweed biofertilizer added to the sodium alginate gel, the necessary environmental conditions for the survival of the grass seeds are provided, thereby ensuring the survival rate of the grass seeds.

[0022] The present invention further uses a sulfoaluminate-gypsum mixture to perform secondary wrapping on the outside of the sodium alginate gel microspheres containing grass seeds to form double-shell microspheres of grass seeds, which can protect the grass seeds from external damage during dormancy. When the grass seed double-shell microspheres are used in conjunction with vegetation concrete, the double-shell structure can help the grass resist the damage of the alkaline environment inside the vegetation concrete, further ensuring that the grass seeds can germinate and grow normally.

[0023] The present invention controls the amount of grass seeds in the microspheres by controlling the dosage ratio of grass seeds and sodium alginate, and then controls the droplet size of the grass seed mixed solution dripped into the curing agent and the stirring time of the grass seed microspheres in the sulphoaluminate-gypsum mixture to achieve flexible control of the size of the grass seed double-shell microspheres and achieve precise sowing.

[0024] After the grass seeds are wrapped by sodium alginate gel to form microspheres, the grass seed microspheres with poor or unqualified wrapping effects can be further wrapped through initial screening to avoid waste of materials and grass seeds, and ensure that the grass seed double-shell microspheres entering the vegetation concrete can survive and germinate normally, thus saving costs while ensuring ecological effects.

[0025] The present invention prepares grass seeds and vegetation concrete separately, which will not change the raw material ratio and preparation method of the vegetation concrete itself, ensuring that the mechanical properties and other properties of the vegetation concrete will not be changed. At the same time, it reduces the requirements for the raw materials and preparation methods of the vegetation concrete, and realizes long-term ecological protection of the slope.

[0026] The raw materials used in the grass seed double-shell microspheres prepared by the invention are simple and easily available, low in cost, simple in production process, and easy to promote and apply. DETAILED DESCRIPTION

[0027] The present invention will be further explained below with reference to specific embodiments. It should be noted that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be subject to the contents of the claims. Any modifications or substitutions made to the technical solution of the present invention by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0028] Example 1

[0029] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:2 to prepare a nutrient substance;

[0030] (2) 1 part sodium alginate, 1 part nutrient, 5 parts Tween-80, and 94 parts deionized water were added to prepare a mixed solution; then 25 parts of foxtail grass seeds were added and stirred for 10 minutes to prepare a foxtail grass seed mixed solution;

[0031] (3) Take 1 part of sulphoaluminate and 1 part of gypsum, add 48 parts of deionized water to prepare a sulphoaluminate-gypsum mixture; take 5 parts of calcium nitrate and add deionized water to prepare a saturated calcium nitrate solution;

[0032] (4) adding the mixed solution of foxtail grass seeds obtained in step (2) dropwise (dropping speed 2s / drop, droplet size 0.3mm) to the saturated calcium nitrate solution obtained in step (3) using a syringe with an inner diameter of 0.25-0.55mm, stirring evenly and solidifying for 4h, and then air-drying at 30°C for 24h to obtain foxtail grass seed microspheres;

[0033] (5) Add the foxtail grass microspheres obtained in step (4) to the sulphoaluminate-gypsum mixture prepared in step (3), stir and mix for 5 minutes, then filter and place in a vacuum drying oven at 25° C. to dry for 8 hours to obtain foxtail grass double-shell microspheres.

[0034] Example 2

[0035] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:3 to prepare a nutrient substance;

[0036] (2) 3 parts of sodium alginate, 5 parts of nutrients, and 5 parts of Span-80 were added to 97 parts of deionized water to prepare a mixed solution; then 27 parts of foxtail grass seeds were added and stirred for 12 minutes to prepare a foxtail grass seed mixed solution;

[0037] (3) Take 1 part of sulphoaluminate and 2 parts of gypsum, add 47 parts of deionized water to prepare a sulphoaluminate-gypsum mixture; take 5 parts of calcium nitrate and add deionized water to prepare a saturated calcium nitrate solution;

[0038] (4) adding the mixed solution of foxtail grass seeds obtained in step (2) dropwise (dropping speed 2s / drop, droplet size 0.3mm) to the saturated calcium nitrate solution obtained in step (3) using a syringe with an inner diameter of 0.25-0.55mm, stirring evenly and solidifying for 5h, and then air-drying at 25°C for 24h to obtain foxtail grass seed microspheres;

[0039] (5) Add the foxtail grass microspheres obtained in step (4) to the sulphoaluminate-gypsum mixture prepared in step (3), stir and mix for 5 minutes, then filter and place in a vacuum drying oven at 20° C. to dry for 8 hours to obtain foxtail grass double-shell microspheres.

[0040] Example 3

[0041] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:4 to prepare a nutrient substance;

[0042] (2) 5 parts of sodium alginate, 10 parts of nutrients, and 5 parts of Span-80 were added to 95 parts of deionized water to prepare a mixed solution; then 30 parts of bluegrass seeds were added and stirred for 10 minutes to prepare a bluegrass seed mixed solution;

[0043] (3) 2 parts of sulphoaluminate and 2 parts of gypsum were added to 46 parts of deionized water to prepare a sulphoaluminate-gypsum mixture; 5 parts of calcium lactate were added to deionized water to prepare a saturated calcium lactate solution;

[0044] (4) adding the bluegrass seed mixed solution obtained in step (2) dropwise (dropping speed 3 s / drop, droplet size 0.35 mm) to the calcium lactate saturated solution obtained in step (3) using a syringe with an inner diameter of 0.25-0.55 mm, stirring evenly and curing for 3 h, and then air-drying at 35° C. for 18 h to obtain bluegrass seed microspheres;

[0045] (5) Add the bluegrass seed microspheres obtained in step (4) to the sulfoaluminate-gypsum mixture prepared in step (3), stir and mix for 10 minutes, then filter and place in a vacuum drying oven at 30° C. and dry for 8 hours to obtain bluegrass seed double-shell microspheres.

[0046] Example 4

[0047] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:5 to prepare a nutrient substance;

[0048] (2) 4 parts of sodium alginate, 5 parts of nutrients, and 5 parts of Span-80 were added to 96 parts of deionized water to prepare a mixed solution; then 30 parts of alfalfa seeds were added and stirred for 10 minutes to prepare an alfalfa seed mixed solution;

[0049] (3) 2 parts of sulphoaluminate and 2 parts of gypsum were added to 46 parts of deionized water to prepare a sulphoaluminate-gypsum mixture; 5 parts of calcium lactate were added to deionized water to prepare a saturated calcium lactate solution;

[0050] (4) adding the mixed solution of alfalfa seeds obtained in step (2) dropwise (dropping speed 3 s / drop, droplet size 0.35 mm) to the saturated solution of calcium lactate obtained in step (3) using a syringe with an inner diameter of 0.25-0.55 mm, stirring evenly and solidifying for 6 h, and then air-drying at 30° C. for 24 h to obtain alfalfa seed microspheres;

[0051] (5) Adding the alfalfa seed microspheres obtained in step (4) to the sulfoaluminate-gypsum mixture prepared in step (3), stirring and mixing for 5 minutes, then filtering and drying in a vacuum drying oven at 30° C. for 10 hours to obtain alfalfa seed double-shell microspheres.

[0052] Example 5

[0053] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:6 to prepare a nutrient substance;

[0054] (2) 6 parts of sodium alginate, 15 parts of nutrients, and 6 parts of Span-80 were added to 94 parts of deionized water to prepare a mixed solution; then 30 parts of alfalfa seeds were added and stirred for 10 minutes to prepare an alfalfa seed mixed solution;

[0055] (3) Take 2 parts of sulphoaluminate and 8 parts of gypsum, add 40 parts of deionized water to prepare a sulphoaluminate-gypsum mixture; take 5 parts of calcium lactate and add deionized water to prepare a saturated calcium lactate solution;

[0056] (4) adding the mixed solution of alfalfa seeds obtained in step (2) dropwise (dropping speed 3 s / drop, droplet size 0.35 mm) to the saturated solution of calcium lactate obtained in step (3) using a syringe with an inner diameter of 0.25-0.55 mm, stirring evenly and solidifying for 6 h, and then air-drying at 35° C. for 12 h to obtain alfalfa seed microspheres;

[0057] (5) Adding the alfalfa seed microspheres obtained in step (4) to the sulfoaluminate-gypsum mixture prepared in step (3), stirring and mixing for 5 minutes, then filtering and drying in a vacuum drying oven at 40° C. for 8 hours to obtain alfalfa seed double-shell microspheres.

[0058] Example 6

[0059] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:8 to prepare a nutrient substance;

[0060] (2) 10 parts of sodium alginate, 15 parts of nutrients, and 10 parts of Span-80 were added to 90 parts of deionized water to prepare a mixed solution; then 35 parts of alfalfa seeds were added and stirred for 30 minutes to prepare an alfalfa seed mixed solution;

[0061] (3) 2 parts of sulphoaluminate and 8 parts of gypsum were added to 40 parts of deionized water to prepare a sulphoaluminate-gypsum mixture; 10 parts of calcium lactate were added to deionized water to prepare a saturated calcium lactate solution;

[0062] (4) adding the mixed solution of alfalfa seeds obtained in step (2) dropwise (dropping speed 5 s / drop, droplet size 0.5 mm) to the saturated solution of calcium lactate obtained in step (3) using a syringe with an inner diameter of 0.25-0.55 mm, stirring evenly and solidifying for 6 h, and then air-drying at 35° C. for 12 h to obtain alfalfa seed microspheres;

[0063] (5) Adding the alfalfa seed microspheres obtained in step (4) to the sulfoaluminate-gypsum mixture prepared in step (3), stirring and mixing for 5 minutes, then filtering and drying in a vacuum drying oven at 40° C. for 8 hours to obtain alfalfa seed double-shell microspheres.

[0064] Example 7

[0065] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:6 to prepare a nutrient substance;

[0066] (2) 6 parts of sodium alginate, 15 parts of nutrients, and 6 parts of Span-80 were added to 94 parts of deionized water to prepare a mixed solution; then 10 parts of sparse flower cypress seeds, 10 parts of alfalfa seeds, and 10 parts of bluegrass were added and stirred for 10 minutes to prepare an alfalfa seed mixed solution;

[0067] (3) Take 2 parts of sulphoaluminate and 8 parts of gypsum, add 40 parts of deionized water to prepare a sulphoaluminate-gypsum mixture; take 5 parts of calcium lactate and add deionized water to prepare a saturated calcium lactate solution;

[0068] (4) adding the mixed solution of alfalfa seeds obtained in step (2) dropwise (dropping speed 3 s / drop, droplet size 0.35 mm) to the saturated solution of calcium lactate obtained in step (3) using a syringe with an inner diameter of 0.25-0.55 mm, stirring evenly and solidifying for 6 h, and then air-drying at 35° C. for 12 h to obtain alfalfa seed microspheres;

[0069] (5) Adding the alfalfa seed microspheres obtained in step (4) to the sulfoaluminate-gypsum mixture prepared in step (3), stirring and mixing for 5 minutes, then filtering and drying in a vacuum drying oven at 40° C. for 8 hours to obtain mixed grass seed double-shell microspheres.

[0070] Example 8

[0071] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:6 to prepare a nutrient substance;

[0072] (2) 6 parts of sodium alginate, 15 parts of nutrients, and 6 parts of Span-80 were added to 94 parts of deionized water to prepare a mixed solution; then 5 parts of alfalfa seeds were added and stirred for 10 minutes to prepare an alfalfa seed mixed solution;

[0073] (3) Take 2 parts of sulphoaluminate and 8 parts of gypsum, add 40 parts of deionized water to prepare a sulphoaluminate-gypsum mixture; take 5 parts of calcium lactate and add deionized water to prepare a saturated calcium lactate solution;

[0074] (4) adding the mixed solution of alfalfa seeds obtained in step (2) dropwise (dropping speed 3 s / drop, droplet size 0.35 mm) to the saturated solution of calcium lactate obtained in step (3) using a syringe with an inner diameter of 0.25-0.55 mm, stirring evenly and solidifying for 6 h, and then air-drying at 35° C. for 12 h to obtain alfalfa seed microspheres;

[0075] (5) Adding the alfalfa seed microspheres obtained in step (4) to the sulfoaluminate-gypsum mixture prepared in step (3), stirring and mixing for 5 minutes, then filtering and drying in a vacuum drying oven at 40° C. for 8 hours to obtain alfalfa seed double-shell microspheres.

[0076] Example 9

[0077] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:6 to prepare a nutrient substance;

[0078] (2) 6 parts of sodium alginate, 15 parts of nutrients, and 6 parts of Span-80 were added to 94 parts of deionized water to prepare a mixed solution; then 60 parts of alfalfa seeds were added and stirred for 10 minutes to prepare an alfalfa seed mixed solution;

[0079] (3) Take 2 parts of sulphoaluminate and 8 parts of gypsum, add 40 parts of deionized water to prepare a sulphoaluminate-gypsum mixture; take 5 parts of calcium lactate and add deionized water to prepare a saturated calcium lactate solution;

[0080] (4) adding the mixed solution of alfalfa seeds obtained in step (2) dropwise (dropping speed 3 s / drop, droplet size 0.35 mm) to the saturated solution of calcium lactate obtained in step (3) using a syringe with an inner diameter of 0.25-0.55 mm, stirring evenly and solidifying for 6 h, and then air-drying at 35° C. for 12 h to obtain alfalfa seed microspheres;

[0081] (5) Adding the alfalfa seed microspheres obtained in step (4) to the sulfoaluminate-gypsum mixture prepared in step (3), stirring and mixing for 5 minutes, then filtering and drying in a vacuum drying oven at 40° C. for 8 hours to obtain alfalfa seed double-shell microspheres.

[0082] Comparative Example 1

[0083] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:2 to prepare a nutrient substance;

[0084] (2) 6 parts of sodium alginate, 15 parts of nutrients, and 6 parts of Span-80 were added to 94 parts of deionized water to prepare a mixed solution; then 30 parts of alfalfa seeds were added and stirred for 10 minutes to prepare an alfalfa seed mixed solution;

[0085] (3) Add 5 parts of calcium lactate to deionized water to prepare a saturated calcium lactate solution;

[0086] (4) The mixed solution of alfalfa seeds obtained in step (2) was added dropwise to the saturated solution of calcium lactate obtained in step (3), stirred evenly, and solidified for 6 hours, and then air-dried at 30° C. for 12 hours to obtain alfalfa seed microspheres.

[0087] Comparative Example 2

[0088] (1) coffee grounds and seaweed biofertilizer were mixed in a mass ratio of 1:3 to prepare a nutrient substance;

[0089] (2) 6 parts of sodium alginate, 15 parts of nutrients, and 6 parts of Span-80 were added to 94 parts of deionized water to prepare a mixed solution; then 30 parts of alfalfa seeds were added and stirred for 10 minutes to prepare an alfalfa seed mixed solution;

[0090] (3) 2 parts of sulphoaluminate and 8 parts of gypsum were added to 40 parts of deionized water to prepare a sulphoaluminate-gypsum mixture;

[0091] (4) adding the alfalfa seed mixed solution obtained in step (2) to the sulfoaluminate-gypsum mixed solution obtained in step (3), stirring and mixing for 5 minutes, then filtering and drying in a vacuum drying oven at 40° C. for 8 hours to obtain alfalfa seed microspheres.

[0092] Example 10

[0093] Take 15 parts of the grass microspheres and alfalfa seeds prepared in Examples 1-9 and Comparative Examples 1-2, respectively, and mix them evenly with 250 parts of vegetation concrete, 1200 parts of crushed stone, and 75 parts of water to make vegetation concrete containing grass microspheres or grass seeds. Then, apply the vegetation concrete on the slope. The amount of vegetation concrete used is 510 kg / m 3 , 24-hour shift management, statistics of grass seed germination rate and growth, the results are shown in the table below:

[0094] 3d germination rate Grass seed growth time Slope greening time Grass seed content in microspheres Example 1 88.6％ 5d 10d 86.2％ Example 2 81.3％ 6d 13d 84.5％ Example 3 82.6％ 6d 14d 81.2％ Example 4 90.5％ 4d 9d 83.5％ Example 5 80.4％ 6d 15d 84.9％ Example 6 86.3％ 5d 12d 86.3％ Example 7 75.8％ 8d 19d 84.7％ Example 8 76.5％ 14d 24d 10％ Example 9 50.4％ 15d 26d 96.1％ Comparative Example 1 32.5％ 20d 38d 79.5％ Comparative Example 2 34.9％ 19d 37d 82.8％ Alfalfa seeds 2.4％ die - -

[0095] The results show that when grass seeds are added directly into the vegetation concrete, the grass seeds can germinate but cannot survive, and ecological slope protection cannot be achieved. When only sodium alginate gel (Comparative Example 1) or sulfoaluminate-gypsum is wrapped to form single-shell microspheres (Comparative Example 2), although the grass seed germination rate can be improved, the grass seeds will still be corroded by the alkali inside the vegetation concrete, reducing the grass seed survival rate, so that the grass seed survival rate is only about 35%. Therefore, it takes a long time to achieve the greening of the slope, and it is also easy for the grass seeds to grow unevenly, requiring secondary replanting. When grass seed double-shell microspheres (Examples 1-7) are added to the vegetation concrete, the germination rate of the grass seeds, the time for the grass seeds to grow, and the time for the slope to be greened can be effectively improved, and long-term ecological protection of the slope can be effectively achieved. However, if the number of grass seeds in the double-shell microspheres is too much or too little, it will affect the protective effect of the slope. When there are too many grass seeds, the nutrients contained in the double-shell microspheres cannot meet the germination and growth needs of the excessive grass seeds, resulting in a low grass seed germination rate and a long regreening time; and when there are too few grass seeds, the protective effect will be reduced due to the small number of grass seeds that can germinate, resulting in a long regreening time for the slope. In addition, it will also cause a waste of nutrients in the double-shell microspheres.

Claims

1. A method for preparing grass seed double-shell microspheres suitable for vegetation concrete, characterized by: The steps include: (1) Mix grass seeds, sodium alginate, nutrients and emulsifier in proportion, and add deionized water to prepare a grass seed mixed solution; (2) preparing a curing agent into a saturated curing agent solution; preparing a sulphoaluminate-gypsum mixed solution; (3) Add the grass seed mixture dropwise to the saturated solution of the curing agent and cure for 3-6 hours, then dry the resulting grass seed microspheres; (4) adding the grass seed microspheres into the sulphoaluminate-gypsum mixture, stirring for 5-10 minutes, and filtering and drying to obtain the grass seed double-shell microspheres; The grass seed double-shell microspheres include 25-35 parts of grass seeds, 1-15 parts of nutrients, 1-10 parts of sodium alginate, 5-10 parts of emulsifier, 5-15 parts of curing agent, 1-2 parts of sulphoaluminate and 1-8 parts of gypsum.

2. The preparation method according to claim 1, wherein: The drying in step (3) and step (4) is air drying for 12-72 hours or vacuum drying at 20-40°C for 8-12 hours.

3. The preparation method according to claim 1, wherein: The diameter of the grass seed double-shell microspheres in step (4) is 1.5-3.0 mm, and the number of grass seeds in the grass seed double-shell microspheres is 500-1000.

4. The preparation method according to claim 1, wherein: The grass seeds are one or more of foxtail grass, bluegrass, alfalfa, bermudagrass, sparsely flowered cypress, zoysia grass or blunt-leaved grass.

5. The preparation method according to claim 1, wherein: The nutrient substance is a mixture of coffee grounds and seaweed biofertilizer, wherein the mass ratio of coffee grounds to seaweed biofertilizer is 1:8-1:

2.

6. The preparation method according to claim 1, wherein: The emulsifier is Tween-80 or Span-80.

7. The preparation method according to claim 1, wherein: The curing agent is any one of calcium nitrate, calcium lactate or aluminum nitrate.

8. Use of grass seed double-shell microspheres prepared by the preparation method according to any one of claims 1 to 7 in slope protection.

9. The use according to claim 8, characterized in that: The slope protection material is vegetated concrete.