Ecological bank protection material and manufacturing method thereof

Abstract

The invention relates to the technical field of environmental engineering, in particular to an ecological bank protection material and a manufacturing method thereof. The ecological bank protection material is prepared from the following substances in parts by mass: 35 to 50 parts of geopolymer gel material, 5 to 15 parts of charcoal functional filler, 3 to 8 parts of microbial curing agent, 1 to 3 parts of plant fiber, 30 to 45 parts of multi-graded aggregate, 2 to 3 parts of binder, 1 to 2 parts of urea and 0 to 8 parts of sea-grass-imitating flexible fiber bundle. Meanwhile, the invention further provides a method for preparing the ecological bank protection material, and the prepared ecological bank protection material is high in compressive strength, low in shrinkage rate, good in permeability coefficient and excellent in performance and has very good application value.

Description

Technical Field

[0001] This invention relates to the field of environmental engineering and technology, specifically to an ecological bank protection material and its manufacturing method. Background Technology

[0002] Traditional bank protection often uses hard materials such as mortar-grouted or dry-laid rubble, cast-in-place concrete, and precast concrete blocks. While these materials have maintained the structural stability of the bank to some extent, prevented soil erosion, and played a role in flood control and drainage, their hard nature, which leaves no vegetation, has disrupted the material and energy cycle system between water, soil, and organisms, resulting in a variety of negative impacts on the landscape, environment, and ecology.

[0003] Ecological bank protection differs from traditional hard bank protection methods. Instead, it comprehensively utilizes natural materials such as plants, wood, and stone, as well as ecological engineering techniques. While meeting the basic functions of bank slope stability and flood control and drainage, it also takes into account ecological restoration, landscape enhancement, and environmental improvement.

[0004] Ecological revetments restore the permeability and aeration of riverbank slopes, creating the necessary conditions for biological growth and habitat, thereby rebuilding the material, energy, and information exchange channels between riverine and terrestrial ecosystems. As the transition zone between these two ecosystems, ecological revetments have a significant edge effect, playing a vital role in maintaining riverbed stability, increasing the diversity of plant and animal species, enhancing biodiversity and ecosystem productivity, improving the self-purification capacity of water bodies, and improving the microclimate of adjacent areas.

[0005] Currently, ecological bank protection materials have developed into several mature types, each with its unique composition, functional characteristics, and applicable conditions. They mainly fall into the following categories: 1. Natural Material Slope Protection: Natural vegetation slope protection primarily utilizes plants with extensive root systems, such as turf slope protection and soil bioengineering. This method uses plant roots to stabilize the soil, effectively controlling soil erosion on riverbanks and reducing the erosive effects of rainwater and surface runoff. Simultaneously, vegetation effectively purifies surface pollutants entering waterways, thereby improving water quality and reducing water pollution. Furthermore, natural vegetation can be used for landscaping, ecological restoration, and preventing secondary environmental pollution.

[0006] 2. Composite slope protection using plants and engineering materials: This type of bank protection technology combines plants with artificial materials, mainly including various forms such as soil-wood mesh composite vegetation, green ecological bags, geonet mats for soil stabilization and planting bases, and grid-reinforced biological slope protection. This ecological bank protection method has strong erosion resistance, maintaining the anchoring effect of vegetation and possessing natural ecological characteristics, while also compensating for vegetation deficiencies through artificial techniques. It is more suitable for river slopes with mild erosion.

[0007] 3. Porous Structure Bank Protection Materials: Porous structure bank protection mainly utilizes hollow concrete blocks, eco-bricks, etc., to form a bank protection structure with a porous structure, which is particularly suitable for urban ecological landscape rivers with low sediment content. This bank protection technology provides a stable and continuous supply of nutrients to vegetation through the pores inside the material. At the same time, the pores also act as adsorption and filtration, effectively purifying water quality and degrading pollutants in the water. The outstanding advantage of porous structure bank protection is that it can simultaneously meet the requirements of both landscape-oriented and ecological bank protection, ensuring the structural stability and durability of the bank protection while providing space for vegetation growth and biological habitats.

[0008] 4. Gabion-type bank protection structure: Gabion structures typically refer to gabion structures, which generally utilize materials such as rust-resistant steel wire combined with crushed stone to form a planting substrate. This structure uses wooden, iron, or concrete cages filled with natural stone to create an ecological bank protection method. Construction is convenient and quick, offering higher overall economic benefits, better integrity, good wave protection, and erosion resistance. The main advantages of gabion structures lie in their good permeability and flexibility, allowing them to adapt to slight foundation deformation without compromising structural integrity. Simultaneously, the voids within the gabions provide conditions for vegetation growth; over time, plant roots can further reinforce the structure, forming a more stable ecological bank protection system.

[0009] 5. Timber and Stone Ecological Bank Protection: Timber and stone, as traditional building materials, still have important applications in ecological bank protection. Timber ecological bank protection utilizes logs or wooden components to construct bank protection structures, possessing good hydrophilicity and ecological compatibility, and providing habitats for aquatic organisms. Stone ecological bank protection uses natural stones, pebbles, and other materials, formed through stacking or dry-laying, possessing good erosion resistance and permeability.

[0010] 6. Traditional materials for ecological transformation: These materials are based on traditional revetment materials and undergo ecological transformation by changing their structural form or material composition to endow them with ecological functions. For example, porous permeable concrete creates interconnected pores in the concrete, allowing plants to grow while maintaining a certain structural strength; ecological blocks, through the special design of precast concrete blocks, form cavities that can provide space for plant growth and habitats.

[0011] With the deepening of the concept of ecological water conservancy and the advancement of technology, the development of ecological bank protection materials is showing obvious new trends, shifting from single-function to multi-functional integration, and from simply imitating nature to co-constructing with nature. This is mainly reflected in the following aspects: 1. From Rigid to Ecological: The most significant trend in the development of ecological revetment materials is the shift from a purely engineering safety-oriented approach to a concept prioritizing ecology and multi-objective collaboration. Traditional revetment material selection primarily considers structural stability and durability, while modern ecological revetment materials, while ensuring engineering safety, place greater emphasis on the ecological compatibility and environmental friendliness of the materials. This shift in philosophy has been fully reflected in domestic and international practices. In practice, ecological revetment materials increasingly focus on restoring the ecological functions of natural rivers, including the continuity of the aquatic and terrestrial ecosystems, the smooth flow of material and energy exchange, and the diversity of biological habitats. This means that ecological revetment materials no longer pursue absolute safety under "once-in-a-century" conditions, but rather focus on the system's self-regulation and recovery capabilities, i.e., ecological resilience. This shift in philosophy has led to a move from simply optimizing material performance in ecological revetment materials to a comprehensive consideration of the entire aquatic-terrestrial ecotone ecosystem.

[0012] 2. Integration of Technological Innovation and Materials Science: Another important trend in the development of ecological revetment materials is the deep integration of materials science innovation and ecological engineering technology. This integration is manifested in several aspects: First, the development of new ecological cementing materials, by improving the composition of traditional cement or developing new cementing materials to reduce the alkalinity of materials and provide more favorable conditions for plant growth; second, the application of composite material technology, by organically combining different materials to give full play to their respective advantages.

[0013] 3. Enhanced Ecological Functions and Multifunctional Integration: Future ecological revetment materials will place greater emphasis on enhancing ecological functions and integrating multiple functions. This is reflected not only in the improved ecological performance of the materials themselves, but also in the enhanced ecosystem services provided by the materials after application.

[0014] 4. Improvement of Standardization and Evaluation System: With the promotion and application of ecological revetment technology, the construction of standardization and performance evaluation systems is becoming increasingly important. Traditional revetment material evaluation mainly focuses on mechanical properties and durability, while ecological revetment materials require a more comprehensive evaluation system that covers multiple aspects such as ecological performance, environmental impact, and landscape effects.

[0015] The development of ecological revetment materials has shifted from a purely engineering safety-oriented approach to a concept prioritizing ecology and multi-objective collaboration, resulting in various types such as natural material slope protection, composite slope protection combining plants and engineering materials, porous structure revetments, cage structure revetments, timber and stone revetments, and traditional materials for ecological transformation. Each of these materials has its own advantages, disadvantages, and applicable conditions, requiring selection and combination based on specific circumstances in engineering practice.

[0016] CN111592286B discloses an ecological revetment material with good biocompatibility, comprising the following raw materials and their weight percentages: cement 30%-40%, water 10%-16%, granite powder 9%-15%, fly ash 8%-12%, gravel 7%-10%, binder 3%-7%, water-reducing agent 4%-5%, crushed glass 3%-5%, concrete activator 2.5%-5%, photocatalyst 1%-4%, concrete reinforcing fiber 1.5%-4%, and concrete air-entraining agent 1%-2%. The produced ecological revetment material fully utilizes granite fragments and cutting powder, is energy-saving and environmentally friendly, and features a simple manufacturing process that reduces manufacturing costs. It avoids sourcing the main raw materials for revetment from river channels, reducing the adverse impacts of these projects on the ecological environment, thereby protecting the environment and meeting ecological needs. However, this material still uses cement as the main binder, and its hydration products are highly alkaline, which may inhibit the early growth of plants. In addition, the material has a dense structure and low porosity, which is insufficient in terms of water permeability and providing habitat for organisms, resulting in poor ecological performance and limited application range. Summary of the Invention

[0017] The purpose of this invention is to provide an ecological revetment material, comprising the following components in parts by weight: 35-50 parts of geopolymer cementitious material, 5-15 parts of biochar functional filler, 3-8 parts of microbial curing agent, 1-3 parts of plant fiber, 30-45 parts of multi-graded aggregate, 2-3 parts of binder, 1-2 parts of urea, and 0-8 parts of seaweed-like flexible fiber bundles. The geopolymer cementitious material is composed of steel slag powder, red mud, calcium sulfoaluminate, magnesium oxide, calcium sulfate whiskers, and nano-alumina.

[0018] Furthermore, in the geopolymer cementitious material, the mass ratio of steel slag powder, red mud, calcium sulfoaluminate, magnesium oxide, calcium sulfate whiskers, and nano-alumina is 10:3:2:2:2:1. The red mud needs to be calcined at 600℃ for 2 hours to break the hematite coating layer, significantly improving the effective release rate of alkalinity. Steel slag powder and red mud form a gel under alkaline conditions, and nano-alumina provides nucleation sites for the geopolymer reaction. The calcium sulfoaluminate expander and calcium sulfate whiskers synergistically inhibit shrinkage, reducing the drying shrinkage rate.

[0019] Furthermore, the biochar functional filler is obtained by pyrolyzing straw under anaerobic conditions at 400-600℃. The biochar functional filler has a specific surface area ≥300m² / g, a porosity ≥80%, and a particle size distribution of 0.5-3mm. The straw is corn straw or cotton straw. Biochar provides micron-level pores, offering a huge specific surface area for adsorbing pollutants. The interface between plant fibers and aggregate forms millimeter-level pores, and the permeable mesh design forms centimeter-level pores. This multi-level porous structure ensures water permeability while providing habitat for plants and animals.

[0020] Furthermore, the microbial solidifying agent is a compound bacterial agent of Bacillus pasteurellii and Bacillus licheniformis, with a bacterial concentration of 10. 8 -10 9 CFU / g, wherein the mass ratio of Bacillus pasteurellii to Bacillus licheniformis is 2:1. Bacillus pasteurellii decomposes urea to produce carbonate ions, which combine with magnesium ions provided by magnesium oxide to form magnesite, filling micropores and increasing density. At the same time, Bacillus licheniformis can decompose organic matter to produce biofilm, enhancing interparticle adhesion.

[0021] Furthermore, the plant fiber is a mixture of palm fiber and coconut shell fiber, with a fiber length of 3-5cm and an aspect ratio of ≥20:1, wherein the mass ratio of palm fiber to coconut shell fiber is 1:1.

[0022] Furthermore, the multi-graded aggregate consists of concrete and natural crushed stone in a 1:1 mass ratio. The aggregate forms the skeleton of the material, providing mechanical support, while the pores within it provide channels for the flow of water and air.

[0023] Furthermore, the binder is prepared by mixing xanthan gum, sodium alginate, and silane coupling agent KH-550 in a mass ratio of 1:1:0.5 and ball milling for 3 hours. Sodium alginate and xanthan gum not only enhance strength, but the resulting electrolyte complex can also absorb a large amount of water, providing buffer protection for microorganisms during wet-dry cycles.

[0024] Furthermore, the seaweed-inspired flexible fiber bundles are made of polycaprolactone through electrospinning, with a fiber bundle length of 8-15 cm. This mimics the interaction between flexible structures and water flow in the seaweed ecosystem. In nature, seaweed effectively dissipates wave energy and creates a slow-flowing zone suitable for organisms by swaying with the water flow.

[0025] This invention also provides a method for preparing the above-mentioned ecological revetment material, comprising the following steps: S1. Mixing and stirring: Weigh each component according to the mass fraction, use a twin-shaft mixer to dry mix each component at a rate of 60-80 r / min for 20-60 min, then add 15-20% water of the total mass, and continue stirring for 30-60 min to form a homogeneous slurry; S2. Hydraulic molding: The homogeneous slurry is injected into the mold and pressed into a hollow multilayer grid unit by a hydraulic molding machine under a pressure of 15-25MPa for 2-10 minutes. S3. Curing and solidification: After molding, the specimens are cured at 23~27℃ and humidity ≥90% for 24 hours before demolding, and then continue standard curing until the specified age.

[0026] Furthermore, the curing process in step S3 includes a microbial-induced calcium carbonate precipitation reaction, in which Bacillus pasteurellium in the microbial curing agent decomposes urea to produce carbonate ions, which combine with magnesium ions provided by magnesium oxide to form magnesite that fills the micropores, thereby improving the compressive strength of the material.

[0027] This invention integrates multi-material system design, multi-scale structural regulation, and ecological function; its core innovation lies in: 1. Material composition design: Geological polymer cementing system is used to replace traditional cement, combined with biochar functional filler, microbial curing agent, etc., to form an organic-inorganic-biological composite system.

[0028] 2. Structural design: The structure adopts a permeable layered grid structure, which achieves wave energy dissipation through stepped staggered overlapping and interlocking design, while providing habitat for animals and plants.

[0029] 3. Synergistic Function: The components are not simply mixed, but rather their performance is synergistically enhanced through interactions at the physical, chemical, and biological levels. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.

[0031] Example 1: An ecological revetment material comprising the following substances: 40 kg of geopolymer cementitious material, 10 kg of biochar functional filler, 5 kg of microbial solidifying agent, 2 kg of plant fiber, 30 kg of multi-grade aggregate, 2.5 kg of binder, 1 kg of urea, and 4 kg of seaweed-like flexible fiber bundles. The geopolymer cementitious material is composed of 20 kg of steel slag powder, 6 kg of red mud, 4 kg of calcium sulfoaluminate, 4 kg of magnesium oxide, 4 kg of calcium sulfate whiskers, and 2 kg of nano-alumina. The red mud needs to be calcined at 600℃ for 2 hours to break the hematite coating layer, thereby significantly improving the effective release rate of alkalinity.

[0032] The biochar functional filler is obtained by pyrolysis of cotton stalks under anaerobic conditions at 400-600℃. It has a specific surface area of ​​305 m² / g, a porosity of 82%, and a particle size distribution of 0.5-3 mm.

[0033] The microbial solidifying agent is a compound bacterial agent of Bacillus pasteurellii and Bacillus licheniformis, with a bacterial concentration of 3 × 10⁻⁶. 8 CFU / g, wherein the mass ratio of Bacillus pasteurellii to Bacillus licheniformis is 2:1.

[0034] The plant fiber is a mixture of palm fiber and coconut shell fiber, with a fiber length of 3-5cm and an aspect ratio of ≥20:1, wherein the mass ratio of palm fiber to coconut shell fiber is 1:1.

[0035] The multi-graded aggregate consists of 15 kg of concrete and 15 kg of natural crushed stone in a 1:1 mass ratio.

[0036] The adhesive is prepared by mixing 1 kg xanthan gum, 1 kg sodium alginate, and 0.5 kg KH-550 silane coupling agent and ball milling for 3 hours.

[0037] The seaweed-like flexible fiber bundles are made of polycaprolactone by electrospinning, and the fiber bundle length is 8-15cm.

[0038] The above-mentioned method for preparing ecological revetment materials includes the following steps: S1. Mixing and stirring: Weigh each component according to the mass fraction, use a twin-shaft mixer to dry mix each component at a rate of 60-80 r / min for 25 min, then add 18% of the total mass of water, and continue stirring for 35 min to form a homogeneous slurry; S2. Hydraulic forming: The homogeneous slurry is injected into the mold and pressed into a hollow layered grid unit by holding the pressure at 20MPa for 4 minutes using a hydraulic forming machine. S3. Curing and solidification: After molding, the specimens are cured at 23~27℃ and 92% humidity for 24 hours before demolding, and then continue standard curing until the specified age.

[0039] The curing process in step S3 includes a microbial-induced calcium carbonate precipitation reaction. The Bacillus pasteurellium in the microbial curing agent decomposes urea to produce carbonate ions, which combine with magnesium ions provided by magnesium oxide to form magnesite that fills the micropores, thereby improving the compressive strength of the material.

[0040] Example 2: An ecological bank protection material, comprising the following substances: 40 kg of geopolymer cementitious material, 10 kg of biochar functional filler, 5 kg of microbial solidifying agent, 2 kg of plant fiber, 30 kg of multi-grade aggregate, 2.5 kg of binder, and 1 kg of urea. The geopolymer cementitious material is composed of 20 kg of steel slag powder, 6 kg of red mud, 4 kg of calcium sulfoaluminate, 4 kg of magnesium oxide, 4 kg of calcium sulfate whiskers, and 2 kg of nano-alumina. The red mud needs to be calcined at 600℃ for 2 hours to break the hematite coating layer, thereby significantly improving the effective release rate of alkalinity.

[0041] The biochar functional filler is obtained by pyrolysis of cotton stalks under anaerobic conditions at 400-600℃. It has a specific surface area of ​​305 m² / g, a porosity of 82%, and a particle size distribution of 0.5-3 mm.

[0042] The microbial solidifying agent is a compound bacterial agent of Bacillus pasteurellii and Bacillus licheniformis, with a bacterial concentration of 3 × 10⁻⁶. 8 CFU / g, wherein the mass ratio of Bacillus pasteurellii to Bacillus licheniformis is 2:1.

[0043] The plant fiber is a mixture of palm fiber and coconut shell fiber, with a fiber length of 3-5cm and an aspect ratio of ≥20:1, wherein the mass ratio of palm fiber to coconut shell fiber is 1:1.

[0044] The multi-graded aggregate consists of 15 kg of concrete and 15 kg of natural crushed stone in a 1:1 mass ratio.

[0045] The adhesive is prepared by mixing 1 kg xanthan gum, 1 kg sodium alginate, and 0.5 kg silane coupling agent KH-550, and then ball milling for 3 hours.

[0046] The above-mentioned method for preparing ecological revetment materials includes the following steps: S1. Mixing and stirring: Weigh each component according to the mass fraction, use a twin-shaft mixer to dry mix each component at a rate of 60-80 r / min for 25 min, then add 18% of the total mass of water, and continue stirring for 35 min to form a homogeneous slurry; S2. Hydraulic forming: The homogeneous slurry is injected into the mold and pressed into a hollow layered grid unit by holding the pressure at 20MPa for 4 minutes using a hydraulic forming machine. S3. Curing and solidification: After molding, the specimens are cured at 23~27℃ and 92% humidity for 24 hours before demolding, and then continue standard curing until the specified age.

[0047] The curing process in step S3 includes a microbial-induced calcium carbonate precipitation reaction. The Bacillus pasteurellium in the microbial curing agent decomposes urea to produce carbonate ions, which combine with magnesium ions provided by magnesium oxide to form magnesite that fills the micropores, thereby improving the compressive strength of the material.

[0048] Comparative Example 1: The adhesive component in Example 2 was removed, and the rest was the same as in Example 2, so it will not be repeated here.

[0049] Comparative Example 2: The microbial solidifying agent component in Example 2 was removed, and the rest was the same as in Example 2, so it will not be repeated here.

[0050] Comparative Example 3: The step of calcining red mud at 600℃ for 2 hours in Example 2 was removed, and non-calcined red mud was used. The rest was the same as in Example 2, and will not be repeated here.

[0051] The performance of the ecological revetment materials prepared in the above embodiments and comparative examples was tested, and the test results are shown in Table 1.

[0052] Table 1 Performance Test Results

[0053] Table 1 shows that the ecological revetment materials prepared in Examples 1 and 2 have high compressive strength, low shrinkage, good permeability, and excellent performance. The addition of seaweed-like flexible fiber bundles further enhances the technical effect. Data from Comparative Example 1 indicates that removing the binder component significantly reduces product performance. Data from Comparative Example 2 shows that the lack of a microbial curing agent slightly reduces product performance. Data from Comparative Example 3 shows that without calcination of the red mud, the synthesis process of the geopolymer cementitious material is not well-reacted, resulting in a significant decrease in the final product performance. The examples described above are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

Claims

1. An ecological bank protection material, characterized in that, The material comprises the following components in parts by weight: 35-50 parts of geopolymer cementitious material, 5-15 parts of biochar functional filler, 3-8 parts of microbial curing agent, 1-3 parts of plant fiber, 30-45 parts of multi-grade aggregate, 2-3 parts of binder, 1-2 parts of urea, and 0-8 parts of seaweed-like flexible fiber bundles. The geopolymer cementitious material is composed of steel slag powder, red mud, calcium sulfoaluminate, magnesium oxide, calcium sulfate whiskers, and nano-alumina.

2. The ecological bank protection material according to claim 1, characterized in that, In the geological polymer cementitious material, the mass ratio of steel slag powder, red mud, calcium sulfoaluminate, magnesium oxide, calcium sulfate whiskers and nano alumina is 10:3:2:2:2:

1. The red mud needs to be calcined at 600℃ for 2 hours to break the hematite coating layer, so as to significantly improve the effective release rate of alkalinity.

3. The ecological bank protection material according to claim 1, characterized in that, The biochar functional filler is obtained by pyrolysis of straw under anaerobic conditions at 400-600℃. The biochar functional filler has a specific surface area ≥300m² / g, a porosity ≥80%, and a particle size distribution of 0.5-3mm. The straw is corn straw or cotton straw.

4. The ecological bank protection material according to claim 1, characterized in that, The microbial solidifying agent is a compound bacterial agent of Bacillus pasteurellii and Bacillus licheniformis, with a bacterial concentration of 10. 8 -10 9 CFU / g, wherein the mass ratio of Bacillus pasteurellii to Bacillus licheniformis is 2:

1.

5. The ecological bank protection material according to claim 1, characterized in that, The plant fiber is a mixture of palm fiber and coconut shell fiber, with a fiber length of 3-5cm and an aspect ratio of ≥20:1, wherein the mass ratio of palm fiber to coconut shell fiber is 1:

1.

6. The ecological bank protection material according to claim 1, characterized in that, The multi-graded aggregate consists of concrete and natural crushed stone in a 1:1 mass ratio.

7. The ecological bank protection material according to claim 1, characterized in that, The binder is prepared by mixing xanthan gum, sodium alginate and silane coupling agent KH-550 in a mass ratio of 1:1:0.5 and ball milling for 3 hours.

8. The ecological bank protection material according to claim 1, characterized in that, The seaweed-like flexible fiber bundles are made of polycaprolactone by electrospinning, and the fiber bundle length is 8-15cm.

9. A method for preparing an ecological bank protection material according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Mixing and stirring: Weigh each component according to the mass fraction, use a twin-shaft mixer to dry mix each component at a rate of 60-80 r / min for 20-60 min, then add 15-20% water of the total mass, and continue stirring for 30-60 min to form a homogeneous slurry; S2. Hydraulic molding: The homogeneous slurry is injected into the mold and pressed into a hollow multilayer grid unit by a hydraulic molding machine under a pressure of 15-25MPa for 2-10 minutes. S3. Curing and solidification: After molding, the specimens are cured at 23~27℃ and humidity ≥90% for 24 hours before demolding, and then continue standard curing until the specified age.

10. The method for preparing the ecological revetment material according to claim 9, characterized in that, The curing process in step S3 includes a microbial-induced calcium carbonate precipitation reaction. The Bacillus pasteurellium in the microbial curing agent decomposes urea to produce carbonate ions, which combine with magnesium ions provided by magnesium oxide to form magnesite that fills the micropores, thereby improving the compressive strength of the material.

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