An erosion-resistant revetment ecological concrete formulation

Abstract

The present application relates to the technical field of concrete, in particular to a kind of anti-scouring revetment ecological concrete formula.It includes raw materials: cement: 420kg-480kg;Coarse aggregate: 840kg-960kg;Fine aggregate: 460kg-540kg;Biochar: 90kg-120kg;Sodium carboxymethyl cellulose: 6kg-10kg;Water reducing agent: 4kg-5.6kg;Water: 170kg-200kg;In the anti-scouring revetment ecological concrete formula, by the amount of each raw material and preparation, biochar optimizes the pore structure of concrete, improves the compactness, enhances the anti-scouring performance;Sodium carboxymethyl cellulose is combined with biochar, forms a protective film with viscosity and toughness, effectively buffers the impact force of water flow, reduces the loss of biochar and the wear of concrete surface;At the same time, water reducing agent reduces water consumption, improves the strength and durability of concrete, further enhances the anti-scouring ability;Under long-term water scouring or rainstorm erosion, the concrete can effectively maintain the stability of structure, reduce the risk of surface wear and peeling, reduce the cost of engineering maintenance and safety hazard.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete, in particular to a kind of anti-scouring revetment ecological concrete formula. BACKGROUND

[0002] At present, in various types of revetment engineering, such as river bank revetment in water conservancy engineering, road side slope protection in traffic engineering and landscape slope maintenance in municipal engineering, concrete materials are widely used. However, the traditional revetment concrete material has some shortcomings. On the one hand, the traditional concrete is usually a rigid structure with low porosity, which is not conducive to plant growth and difficult to achieve the function of ecological revetment, leading to imbalance of slope ecosystem and affecting the landscape effect. On the other hand, its anti-scouring performance is limited, and under the long-term scouring of water flow or rainstorm erosion, the concrete surface is prone to wear and tear, which weakens the overall stability of the revetment and increases the maintenance cost and safety hazard of the project.

[0003] For example, the Chinese patent publication No. CN108395169A proposes a kind of concrete for revetment block and preparation method of revetment block, the revetment block concrete prepared by the invention has certain strength and stability, and improves the ecological performance of revetment to a certain extent, providing certain basic conditions for plant growth. However, in terms of ecological performance, although the prepared concrete has certain porosity for partial plant root penetration, the porosity distribution is not uniform and the connectivity is poor, which limits the growth space of plant root system.

[0004] From the perspective of anti-scouring performance, due to the problems of uneven porosity distribution and poor connectivity of the above-mentioned concrete, the internal structure of the concrete is relatively weak. When water flow scours, water flow is more likely to invade the internal structure of the concrete, accelerating the erosion of the concrete. At the same time, lacking a stable network of plant root system, the impact force of water flow cannot be buffered by the adhesion and friction of plant root system, so that the surface of the concrete directly bears a large water flow force, which not only accelerates the wear and tear of the concrete surface, but also may cause loosening and damage of the internal structure, thereby reducing the long-term effectiveness and sustainability of ecological revetment and affecting the repair and protection effect on the ecological environment of slope surface.

[0005] Therefore, there is an urgent need for an anti-scouring revetment ecological concrete formula. SUMMARY

[0006] The present application aims to provide an anti-scouring revetment ecological concrete formula to solve the problems raised in the background art.

[0007] To achieve the above-mentioned purpose, the present application provides an anti-scouring revetment ecological concrete formula, which comprises the following raw materials:

[0008] Cement: 420kg-480kg; coarse aggregate: 840kg-960kg, reinforcing the skeleton structure of concrete; fine aggregate: 460kg-540kg, filling the gap between coarse aggregate, improving the workability of concrete; biochar: 90kg-120kg, which can enhance the erosion resistance and ecological performance; sodium carboxymethyl cellulose: 6kg-10kg, which can further improve the erosion resistance, water retention and other properties in combination with biochar; water reducing agent: 4kg-5.6kg, reducing the water consumption of concrete, improving the strength and durability of concrete; water: 170kg-200kg;

[0009] The biochar is prepared from crop straw and starch-based hydrogel to form a pore structure, which is used to enhance the compactness and erosion resistance and provide nutrients for plant production; and the biochar is combined with sodium carboxymethyl cellulose to form a protective film with viscosity and toughness, which is used to buffer the impact force of water flow.

[0010] In the present application, the biochar can optimize the pore structure of concrete, improve the compactness, enhance the erosion resistance and ecological performance, the sodium carboxymethyl cellulose combined with the biochar can buffer the water flow impact, reduce material loss and wear, improve water retention performance and help plant growth; the cement is combined with coarse and fine aggregate to construct a stable skeleton, and the water reducing agent reduces the water consumption, thereby improving the strength and durability; not only effectively improving the erosion resistance, reducing the engineering maintenance cost and safety hazards, but also promoting the ecological restoration and balance of the slope, and realizing the ecological slope protection.

[0011] Secondly, according to Figure 1 As shown in the figure, the present application provides a preparation method of an erosion-resistant slope protection ecological concrete formula, comprising the following steps:

[0012] S1.1, dry mixing: first, the cement, coarse aggregate, fine aggregate and biochar are added to the concrete mixer, and the mixer is started for dry mixing, so that the solid raw materials are fully mixed and uniform;

[0013] S1.2, dissolving sodium carboxymethyl cellulose and water reducing agent: prepare two containers, add 26%-30% of the total water amount of water to the first container, add sodium carboxymethyl cellulose to the water, stir at a stirring speed of 120r / min-180r / min for 20min-30min, so that it is fully dissolved to form a uniform solution; then pour the remaining water and water reducing agent into the second container, and stir at a stirring speed of 160r / min-240r / min for 6min-10min, so that the water reducing agent is fully dissolved in the water;

[0014] S1.3, wet stirring: the dissolved sodium carboxymethyl cellulose solution and water reducing agent solution are added into the blender in turn, the blender is started, and stirring is carried out at a stirring speed of 80 r / min-120 r / min for 4 min-6 min, so that all the raw materials are fully mixed to form a concrete mixture;

[0015] S1.4, pouring and forming: the stirred concrete mixture is poured into the slope protection mold, a vibrator is used, the vibration frequency of the vibrator is adjusted to 6000 times / min-10000 times / min, vibration work is carried out, the concrete is compacted, the internal air is discharged, and the initially formed anti-erosion slope protection ecological concrete is obtained;

[0016] S1.5, curing: the formed concrete is cured, and water is sprayed 3-4 times a day to keep the surface of the concrete wet, and the anti-erosion slope protection ecological concrete is obtained.

[0017] In the present application, through the preparation steps of the anti-erosion slope protection ecological concrete formula, the raw materials can be fully mixed and reacted. Dry stirring can uniformly disperse the solid raw materials, and the stirring speed and time of dissolving sodium carboxymethyl cellulose and water reducing agent are controlled to make them fully dissolve and play a role. Wet stirring can deeply mix the raw materials and improve the performance of the concrete. Vibration can improve the compactness of the concrete and improve the strength. Curing promotes cement hydration.

[0018] Thirdly, according to the present application, the preparation of the biological carbon is provided, which comprises the following steps: Figure 2

[0019] S2.1, material preparation: 2cm-3cm long crop straw and starch-based hydrogel (corn starch, acrylamide, N,N'-methylene bisacrylamide, potassium persulfate, deionized water), and the amount of the crop straw and the starch-based hydrogel is 5:2;

[0020] S2.2, mixing materials: first, the crop straw is placed in a high-temperature-resistant ceramic crucible, then the starch-based hydrogel is added, and stirring is carried out using a glass rod for 15 min-20 min, so that the crop straw and the starch-based hydrogel are uniformly mixed;

[0021] S2.3, pyrolysis treatment: the ceramic crucible is placed in a muffle furnace, the temperature is increased at a rate of 5℃ / min from room temperature, until the temperature reaches 500℃, then the temperature is kept constant for 2h, so that the raw materials are fully reacted;

[0022] S2.4, cooling and taking out: after the muffle furnace is cooled to room temperature, the ceramic crucible containing the pyrolysis product is taken out;

[0023] ​S2.5, washing and drying: the pyrolysis products in the ceramic crucible are transferred to a glass beaker, and are repeatedly washed with deionized water for 5-7 times, and then the products are placed in a culture dish and dried in a 105 DEG C oven to constant weight, so that the required biochar is obtained.

[0024] In the present application, through the preparation steps of biochar, the starch-based hydrogel and crop straw are fully mixed and pyrolyzed, and the generated biochar has a rich pore structure; this not only optimizes the concrete pore structure, enhances the compactness and anti-erosion, but also provides nutrients for plant growth, promotes ecological restoration; when the components are combined, the high molecular chain formed by the polymerization of acrylamide in the starch-based hydrogel is combined with the carbon-containing structure generated by the pyrolysis of crop straw through physical winding and reaction between part of active groups; for example, esterification reaction occurs between the hydroxyl group in the starch-based hydrogel and the carboxyl group in the pyrolysis product of straw, the reaction formula is: R-COOH+R ， -OH→R-COO-R ， +H2O (R, R ， represent different groups), which enhances the performance of biochar.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] 1. In the anti-erosion slope protection ecological concrete formula, through the preparation of the amount of each raw material, the biochar optimizes the pore structure of the concrete, improves the compactness, and enhances the anti-erosion performance; the sodium carboxymethyl cellulose is combined with the biochar to form a protective film with viscosity and toughness, which effectively buffers the impact force of water flow and reduces the loss of biochar and the wear of the concrete surface; at the same time, the water reducing agent reduces the water consumption, improves the strength and durability of the concrete, and further enhances the anti-erosion ability; under long-term water flow erosion or rainstorm erosion, the concrete can effectively maintain the stability of the structure, reduce the risk of surface wear and peeling, and reduce the engineering maintenance cost and safety hidden danger.

[0027] 2. In the anti-erosion slope protection ecological concrete formula, the biochar is rich in minerals and trace elements, which can provide nutrients for plant growth and promote plant root development, and the pore structure is also beneficial to plant root penetration, forming a stable root network to reinforce the slope surface, and the sodium carboxymethyl cellulose improves the water retention performance of the concrete, in addition, the components in the formula synergistically promote the material exchange and energy flow between the concrete and the surrounding ecological environment, accelerate the repair and balance of the slope ecological system, and realize ecological slope protection. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The preparation step flowchart of the anti-erosion slope protection ecological concrete formula of the present application;

[0029] Figure 2 The preparation flowchart of the biochar of the present application;

[0030] Figure 3 This is a bar chart showing the wear depth of the anti-erosion device according to the present invention;

[0031] Figure 4 This is a bar chart showing the mass loss due to erosion resistance in this invention.

[0032] Figure 5 This is a bar chart showing the plant germination rate, which is an ecological feature of this invention.

[0033] Figure 6 This is a bar chart showing the average growth height of the organisms in this invention.

[0034] Figure 7 This is a bar chart showing the root penetration rate of the plant in this invention.

[0035] Figure 8 This is a bar chart showing the pore connectivity of the present invention. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] This invention provides a erosion-resistant ecological concrete formula for slope protection, comprising the following raw materials:

[0038] Cement: 420kg-480kg, as the cementitious material for concrete, providing the strength basis; Coarse aggregate: 840kg-960kg, the coarse aggregate is crushed stone, the particle size of the crushed stone is 8mm-20mm; Fine aggregate: 460kg-540kg, the fine aggregate is river sand, the particle size of the river sand is less than 4.5mm; Biochar: 90kg-120kg; Sodium carboxymethyl cellulose: 6kg-10kg; Water-reducing agent: 4kg-5.6kg; Water: 170kg-200kg.

[0039] Among them, according to Figure 2 As shown, the preparation of biochar includes the following steps:

[0040] S2.1 Material Preparation: 2cm-3cm long crop straw and starch-based hydrogel; the ratio of crop straw to starch-based hydrogel is 5:2 (e.g., 500g of crop straw and 200g of starch-based hydrogel); the starch-based hydrogel includes corn starch, acrylamide, crosslinking agent, initiator, and deionized water, wherein the crosslinking agent is N,N'-methylenebisacrylamide; the initiator is potassium persulfate;

[0041] S2.2, mixing materials: first, the crop straw is placed in a high-temperature-resistant ceramic crucible, then starch-based hydrogel is added, a glass rod is used for stirring for 15-20 min, so that the crop straw and the starch-based hydrogel are uniformly mixed;

[0042] S2.3, pyrolysis treatment: the ceramic crucible is placed in a muffle furnace, and the temperature is increased at a rate of 5℃ / min from room temperature until the temperature reaches 500℃, then the temperature is kept constant for 2h, so that the raw materials are fully reacted;

[0043] S2.4, cooling and taking out: after the muffle furnace is cooled to room temperature, the ceramic crucible containing the pyrolysis product is taken out;

[0044] S2.5, cleaning and drying: the pyrolysis product in the ceramic crucible is transferred to a glass beaker, and is repeatedly washed with deionized water for 5-7 times to completely remove the impurities and ash attached to the surface of the pyrolysis product, then the product is placed in a culture dish and is dried in a 105℃ oven until the weight is constant, so that the required biochar is obtained.

[0045] In addition, the amount of corn starch is 200g; the amount of acrylamide is 100g; the amount of N,N'-methylene bisacrylamide is 2g; the amount of potassium persulfate is 1g; and the amount of deionized water is 1000ml;

[0046] The starch-based hydrogel includes the following operation steps:

[0047] 200g of corn starch is added to 500ml of deionized water and stirred uniformly to form a starch paste, 100g of acrylamide is dissolved in 300ml of deionized water in another container and stirred until completely dissolved, then 2g of N,N'-methylene bisacrylamide and 1g of potassium persulfate are added and stirred to dissolve, then the acrylamide mixed solution is slowly poured into the starch paste while stirring, then the remaining 200ml of deionized water is added and stirred uniformly, then the mixed solution is transferred to a mold and sealed, and reacted in a 60℃ water bath for 3h to obtain a starch-based hydrogel, and finally the hydrogel is taken out and repeatedly washed with deionized water to remove unreacted substances, so that the starch-based hydrogel is finally obtained

[0048] According to the embodiment of the present application, a preparation method of an anti-erosion slope protection ecological concrete formula is provided, which comprises the following steps: Figure 1

[0049] S1.1, dry mixing: first, cement, coarse aggregate, fine aggregate and biochar are added to a concrete mixer, the mixer is started for dry mixing, the speed of the dry mixing of the mixer is 60r / min-100r / min, and the mixing time is 2-3min, so that the solid raw materials are fully mixed and uniformly distributed; ​

[0050] S1.2, dissolving sodium carboxymethyl cellulose and water reducing agent: prepare two containers, add 26%-30% of the total water amount of water to the first container, add sodium carboxymethyl cellulose to the water, stir at a stirring speed of 120r / min-180r / min for 20min-30min to make it fully dissolved to form a uniform solution; then pour the remaining water and water reducing agent into the second container, stir at a stirring speed of 160r / min-240r / min for 6min-10min to make the water reducing agent fully dissolved in the water;

[0051] S1.3, wet stirring: add the dissolved sodium carboxymethyl cellulose solution and water reducing agent solution to the blender in turn, turn on the blender, and stir at a stirring speed of 80r / min-120r / min for 4min-6min to make all the raw materials fully mixed to form a concrete mixture;

[0052] S1.4, pouring and forming: pour the stirred concrete mixture into the slope protection mold, use a vibrator, adjust the vibration frequency to 6000 times / min-10000 times / min for vibration work to make the concrete dense and expel the internal air, so that the preliminary formed anti-erosion slope ecological concrete is obtained;

[0053] S1.5, curing: the formed concrete is cured, the curing is carried out in an environment with a temperature of 20±2℃ and a relative humidity of more than 90%, the curing time is 28 days-46 days, and the concrete surface is kept wet by watering 3-4 times a day, so that the anti-erosion slope ecological concrete is obtained.

[0054] In the present application, firstly, by controlling the amount of each raw material and following a series of preparation steps of dry stirring, dissolving, wet stirring, pouring and forming and curing, each raw material is fully mixed and reacted; not only can the pore structure of the concrete be optimized by the biochar to improve the density of the concrete, thereby enhancing the anti-erosion performance, but also the rich minerals and trace elements of the biochar can provide nutrients for plant growth, effectively promoting the repair and balance of the slope ecological system; at the same time, sodium carboxymethyl cellulose and biochar are combined with each other, which can effectively buffer the impact force when the water flow is washed, reduce the loss of biochar and the wear of the concrete surface, and improve the water retention performance of the concrete; the pore structure of the biochar prepared by pyrolysis after mixing starch-based hydrogel and crop straw has the advantages of further optimizing the pores in the concrete, enhancing the density and anti-erosion performance of the concrete, and better promoting plant growth through the synergistic effect with other components in the concrete, thereby effectively improving the effect of slope ecological repair.

[0055] In addition, when the sodium carboxymethyl cellulose and the biochar are combined, a protective film with viscosity and toughness can be formed on the surface of the biochar, which can effectively buffer the impact force when the water flow is washed, reduce the loss of the biochar and the abrasion of the concrete surface, and improve the anti-washing capacity; meanwhile, the water retention performance improves the humidity environment of the concrete, which is beneficial to the plant growth and promotes the slope ecological restoration; the reaction mechanism is mainly that the carboxyl (-COOH) in the sodium carboxymethyl cellulose molecule and the hydroxyl (-OH) on the surface of the biochar form an ester bond (-COO-) through esterification, and meanwhile, there are hydrogen bonds and other interactions between the molecules, which enhance the binding force; the esterification reaction formula can be expressed as: Through the above-mentioned effects, the sodium carboxymethyl cellulose and the biochar are combined closely, and the comprehensive performance of the concrete is improved.

[0056] Through the use of the raw materials, the biochar can optimize the pore structure of the concrete, improve the compactness, and enhance the anti-washing performance; the sodium carboxymethyl cellulose and the biochar are combined to form a protective film with viscosity and toughness, which can effectively buffer the impact force of the water flow, reduce the loss of the biochar and the abrasion of the concrete surface; meanwhile, the water reducing agent reduces the water consumption, improves the strength and durability of the concrete, and further enhances the anti-washing capacity; under the long-term water flow washing or rainstorm erosion, the concrete can effectively maintain the structural stability, reduce the surface abrasion and peeling risk, and reduce the engineering maintenance cost and safety hidden danger.

[0057] The biochar is rich in minerals and trace elements, which can provide nutrients for plant growth and promote the development of plant roots; the pore structure is also beneficial to the root penetration of the plants, forms a stable root network, and reinforces the slope; the sodium carboxymethyl cellulose improves the water retention performance of the concrete; in addition, the components in the formula synergistically promote the material exchange and energy flow between the concrete and the surrounding ecological environment, accelerate the repair and balance of the slope ecological system, and realize the ecological slope protection.

[0058] According to different raw material dosages, the slope ecological concrete provided by the present application is further illustrated through the following specific examples.

[0059] Example 1

[0060] The anti-scouring revetment ecological concrete formulation of the present embodiment uses the following raw material amounts: cement 420 kg; coarse aggregate (gravel, particle size 8-20 mm) 840 kg; fine aggregate (river sand, particle size less than 4.5 mm) 460 kg; biochar 105 kg; sodium carboxymethyl cellulose 6 kg; water reducing agent 4 kg; water 170 kg. In preparation, biochar is prepared first, 500 g of 2-5 cm long crop straw and 200 g of starch-based hydrogel (containing corn starch 200 g, acrylamide 100 g, N,N'-methylene bisacrylamide 2 g, potassium persulfate 1 g, deionized water 1000 ml) are prepared according to the steps, and the biochar is obtained after pyrolysis. Then the concrete is prepared, and dry mixing (mixer speed 60 r / min, stirring 2 min), dissolving sodium carboxymethyl cellulose and water reducing agent (the first container uses 26% of the total water amount, stirring speed 120 r / min, stirring 20 min; the second container stirring speed 160 r / min, stirring 6 min), wet mixing (stirring speed 80 r / min, stirring 4 min), pouring and forming (vibrating frequency 6000 times / min), curing (temperature 20±2℃, relative humidity greater than 90%, curing for 28 days, spraying water 3 times a day) are sequentially performed.

[0061] Example 2

[0062] The anti-scouring revetment ecological concrete formulation of the present embodiment uses the following raw material amounts: cement 420 kg; coarse aggregate (gravel, particle size 8-20 mm) 840 kg; fine aggregate (river sand, particle size less than 4.5 mm) 460 kg; biochar 105 kg; sodium carboxymethyl cellulose 6 kg; water reducing agent 4 kg; water 170 kg. In preparation, biochar is prepared first, 500 g of 2-5 cm long crop straw and 200 g of starch-based hydrogel (containing corn starch 200 g, acrylamide 100 g, N,N'-methylene bisacrylamide 2 g, potassium persulfate 1 g, deionized water 1000 ml) are prepared according to the steps, and the biochar is obtained after pyrolysis. Then the concrete is prepared, and dry mixing (mixer speed 60 r / min, stirring 2 min), dissolving sodium carboxymethyl cellulose and water reducing agent (the first container uses 26% of the total water amount, stirring speed 120 r / min, stirring 20 min; the second container stirring speed 160 r / min, stirring 6 min), wet mixing (stirring speed 80 r / min, stirring 4 min), pouring and forming (vibrating frequency 6000 times / min), curing (temperature 20±2℃, relative humidity greater than 90%, curing for 28 days, spraying water 3 times a day) are sequentially performed.

[0063] Example 3

[0064] The amount of each raw material in the anti-scouring ecological concrete formula of the embodiment is: cement 480 kg; coarse aggregate 960 kg; fine aggregate 540 kg; biochar 120 kg; sodium carboxymethyl cellulose 8 kg; water reducing agent 5.6 kg; and water 200 kg. During the preparation of biochar and concrete, the dry stirring speed is 100 r / min, and the stirring time is 3 min; when dissolving sodium carboxymethyl cellulose, the first container is filled with 30% of the total water, the stirring speed is 180 r / min, and the stirring time is 30 min; when dissolving the water reducing agent, the stirring speed of the second container is 240 r / min, and the stirring time is 10 min; the wet stirring speed is 120 r / min, and the stirring time is 6 min; the vibrating frequency is 10,000 times / min; and the curing time is 46 days, with water spraying 4 times a day.

[0065] Table 1 Amount of each raw material in examples 1-3

[0066] Example 1 Example 2 Example 3 Cement (kg) 420 450 480 Coarse aggregate (kg) 840 900 960 Fine aggregate (kg) 460 500 540 Biochar (kg) 105 95 120 Sodium carboxymethylcellulose (kg) 6 10 8 Water reducing agent (kg) 4 4.8 5.6 Water (kg) 170 185 200

[0067] In order to verify that the slope ecological concrete prepared by the embodiment of the application has good anti-scouring and ecological properties, the following test examples are used to illustrate the slope ecological concrete provided by the embodiment of the application.

[0068] Test example

[0069] The purpose of the test group is to explore the influence of different component proportions on the slope ecological concrete, and to detect the anti-scouring, ecological, plant root penetration rate and pore connectivity rate of the slope ecological concrete of the application.

[0070] Test objective: test group A, test group B and test group C respectively adopt the component proportions of the slope ecological concrete provided by examples 1-3; the control example adopts control group A, control group B, control group C and control group D, wherein:

[0071] Control group A

[0072] A traditional slope protection concrete formula is used, and the main raw materials are cement 500 kg, coarse aggregate (broken stone) 1000 kg, fine aggregate (river sand) 500 kg, and water 200 kg, without adding biochar, sodium carboxymethyl cellulose and water reducing agent. During preparation, the cement, coarse aggregate and fine aggregate are added to the mixer and dry stirred uniformly, then water is added for wet stirring, and after uniform stirring, the mixture is poured into a slope mold, a vibrator is used for vibration molding, and then the mixture is cured at room temperature for 28 days.

[0073] Control group B

[0074] The formula contains cement 440 kg, coarse aggregate 880 kg, fine aggregate 480 kg, water 175 kg, water reducing agent 4.4 kg, and a common additive (similar to ceramsite, which plays a certain role in pore filling) 100 kg. When preparing, each raw material is added in sequence to the mixer, stirred uniformly, and then poured into a mold for curing. The curing is carried out in an environment with a temperature of about 20°C and appropriate humidity for 28 days.

[0075] Control group C

[0076] The concrete formula and preparation method are the same as in Example 1, but no sodium carboxymethyl cellulose is added.

[0077] Control group D

[0078] The concrete formula and preparation method are the same as in Example 1, but no starch-based hydrogel is added to the biochar.

[0079] Test method: According to the anti-erosion, ecological, plant root penetration rate, and pore connectivity rate of the slope protection ecological concrete according to the present application, tests are carried out respectively, and the specific test methods are as follows:

[0080] Anti-erosion test method: A specially designed water flow erosion test tank is used. Concrete test pieces of different groups with a size of 300mm x 300mm x 100mm are fixed at a specific position in the test tank. The water flow speed is set to 2.5m / s, the water flow direction is at a 45° angle to the surface of the test piece, and the erosion time lasts for 36h. After the test is completed, the wear depth of the surface of the concrete test piece is measured using high-precision measuring instruments, and the mass loss of the test piece is accurately measured by weighing equipment. The wear depth and mass loss are used as evaluation indexes. The shallower the wear depth and the smaller the mass loss, the stronger the anti-erosion performance of the concrete.

[0081] Ecological test method: Select grass seeds of the same variety, specification, and similar germination rate, and evenly sow 5 seeds in each planting hole on the surface of the concrete test piece of different groups. Place the test piece in a culture box simulating a natural environment, maintain a temperature of 25±2°C, a relative humidity of 70%-80%, a light intensity of 2000-3000Lux, and a light time of 12 hours / day. After 60 days of cultivation, count the number of germinated seeds on each test piece, calculate the germination rate, measure the average growth height of the germinated plants, and comprehensively evaluate the ecological performance of the concrete based on the germination rate and growth height. The higher the germination rate and the better the plant growth, the better the ecological performance.

[0082] Plant root penetration rate test method: selected plant varieties are planted on the surface of the concrete test piece, maintained for 90 days to ensure normal growth of the plants; after the maintenance period, the concrete test piece is evenly cut into 4 pieces along the vertical direction, and 5 observation points are randomly selected on the cutting surface of each test piece; using a measuring tool, the depth of the plant root penetrating the concrete is measured at each observation point, and the number of penetrating roots is counted; the plant root penetration rate is calculated according to the formula: plant root penetration rate = (total root penetration depth / total concrete test piece thickness x total number of observation points) x 100%; the higher the penetration rate, the more conducive the concrete is to the growth and penetration of plant roots, and the better the ecological friendliness.

[0083] Pore connectivity test method: high-precision industrial CT scanners are used to scan the concrete test pieces of different groups in all directions to obtain high-resolution pore structure images inside the test pieces; the scanned images are imported into professional image processing and analysis software, and the pores are identified, segmented and analyzed through the software algorithm; the volume of connected pores is calculated and compared with the total pore volume of the test piece to obtain the pore connectivity, i.e. pore connectivity = (connected pore volume / total pore volume) x 100%; the higher the pore connectivity, the more reasonable the pore structure inside the concrete, which is conducive to the transmission and growth of water, air and plant roots inside the concrete, and more effective for ecological slope protection.

[0084] The specific detection indexes are shown in Table 2.

[0085] Table 2: Detection indexes of each sample

[0086]

[0087] According to Figures 3-8 and Table 2, the summary of the above comparative data is as follows:

[0088] Anti-erosion performance: the anti-erosion performance of test groups A, B and C of the present application is higher than that of each control group; the wear depth of test groups A, B and C is between 0.6 mm and 1.0 mm, and the mass loss is between 0.2 kg and 0.4 kg, while control group A, as a traditional concrete, has a wear depth of 4.0 mm and a mass loss of 2.5 kg, with poor anti-erosion ability; control group B adds ordinary additives similar to ceramsite, with a wear depth of 3.0 mm and a mass loss of 1.5 kg, with limited improvement; control group C does not add sodium carboxymethyl cellulose, with a wear depth of 2.0 mm and a mass loss of 1.0 kg; control group D does not add starch-based hydrogel in the biochar, with a wear depth of 1.8 mm and a mass loss of 0.8 kg. This shows that the biochar in the present application formula optimizes the pore structure to improve the compactness, the sodium carboxymethyl cellulose and the biochar form a protective film to buffer the water flow impact, the water reducing agent reduces the water consumption to improve the strength and durability, and the components synergistically greatly enhance the anti-erosion performance.

[0089] Ecological performance: the germination rate of the test groups A, B and C is 88% to 92%, and the average growth height is 16 cm to 22 cm, which is higher than that of the control group; the control group A has a low porosity problem, and the germination rate is only 36%, the average growth height is 4 cm, and the ecological performance is poor; the control group B has no obvious effect on the ecological performance, the germination rate is 48%, and the average growth height is 6 cm; the control group C lacks sodium carboxymethyl cellulose, and the water retention performance is insufficient, the germination rate is 72%, and the average growth height is 10 cm; the performance of the control group D is weakened due to the lack of starch-based hydrogel, the germination rate is 76%, and the average growth height is 11 cm. It is proved that the nutrients provided by the biochar in the formula of the application, the porosity of which is beneficial to root penetration, and the water retention performance improved by sodium carboxymethyl cellulose are more conducive to plant growth, and the good ecological slope protection function is realized.

[0090] Plant root penetration rate: the plant root penetration rates of the test groups A, B and C are 62%, 67% and 72% respectively, which are much higher than those of the control group A (18%), the control group B (25%), the control group C (42%) and the control group D (47%); this reflects that the biochar and sodium carboxymethyl cellulose in the concrete of the application jointly optimize the internal structure, so that the plant roots have better penetration conditions, which is beneficial to the formation of a stable root network to reinforce the slope surface, while the lack of components or insufficient components in each control group is not conducive to root penetration.

[0091] Pore connectivity rate: the pore connectivity rates of the test groups A, B and C are 46% to 52%, which are higher than those of the control group A (18%), the control group B (22%), the control group C (32%) and the control group D (38%); it is proved that the pore structure of the biochar in the formula of the application and the synergistic effect with other components, such as sodium carboxymethyl cellulose, optimize the pore structure, so that the internal pore structure of the concrete is more reasonable, which is beneficial to the transmission and growth of water, air and plant roots, and improves the ecological slope protection function, and the pore connectivity of each control group is poor.

[0092] In summary, the anti-scouring slope protection ecological concrete formula of the application effectively reduces wear and tear and mass loss in the anti-scouring performance through the synergistic effect of some components such as biochar, sodium carboxymethyl cellulose and water reducing agent, reduces the engineering maintenance cost and safety hidden danger; in the ecological performance, it promotes plant growth, root penetration and the formation of a reasonable pore structure, accelerates the repair and balance of the slope ecological system, and thus realizes the high-performance ecological slope protection effect.

[0093] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and such changes and improvements are all within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. An erosion resistant revetment eco-concrete formulation, characterized in that, The raw materials include: Cement: 420kg-480kg; coarse aggregate: 840kg-960kg; Fine aggregate: 460kg-540kg; biochar: 90kg-120kg; sodium carboxymethyl cellulose: 6kg-10kg; Water reducing agent: 4kg-5.6kg; water: 170kg-200kg; The biochar is prepared from crop straw and starch-based hydrogel, forms a pore structure, and is used to enhance the compactness and erosion resistance while providing nutrients for plant production; the biochar is combined with sodium carboxymethyl cellulose to form a protective film with viscosity and toughness, which is used to buffer the impact force of water flow; The preparation of the biochar includes the following steps: S2.1, material preparation: 2cm-3cm long crop straw and starch-based hydrogel; S2.2, mixing materials: first put the crop straw into a high-temperature resistant ceramic crucible, then add the starch-based hydrogel, use a glass rod to stir for 15min-20min, so that the crop straw and starch-based hydrogel are uniformly mixed; S2.3, pyrolysis treatment: put the ceramic crucible into a muffle furnace, start heating from room temperature at a rate of 5℃ / min, until the temperature reaches 500℃, then keep the temperature constant for 2h to make the raw materials fully react; S2.4, cooling and taking out: after the muffle furnace cools to room temperature, take out the ceramic crucible containing the pyrolysis product; S2.5, cleaning and drying: transfer the pyrolysis product in the ceramic crucible to a glass beaker, rinse it with deionized water for 5-7 times, then place the product in a petri dish and put it in a 105℃ oven to dry to constant weight, and the desired biochar is obtained; In S2.1, the starch-based hydrogel includes corn starch, acrylamide, crosslinking agent, initiator, and deionized water.

2. The erosion control revetment eco-concrete formulation according to claim 1, wherein, The coarse aggregate uses gravel, and the particle size of the gravel is 8mm-20mm; the fine aggregate uses river sand, and the particle size of the river sand is less than 4.5mm.

3. The erosion control, revetment, eco-concrete formulation of claim 1, wherein, The preparation method also includes the following specific steps: S1.1, dry mixing: first add cement, coarse aggregate, fine aggregate, and biochar into a concrete mixer, start the mixer for dry mixing, so that these solid raw materials are fully mixed and uniform; S1.2, dissolving sodium carboxymethyl cellulose and water reducing agent: prepare two containers, add 26%-30% of the total water to the first container, add sodium carboxymethyl cellulose to the water, stir at a speed of 120r / min-180r / min for 20min-30min to make it fully dissolved, form a uniform solution; then pour the remaining water and water reducing agent into the second container, stir at a speed of 160r / min-240r / min for 6min-10min to make the water reducing agent fully dissolved in the water; S1.3, wet mixing: add the dissolved sodium carboxymethyl cellulose solution and water reducing agent solution to the mixer in turn, start the mixer, stir at a speed of 80r / min-120r / min for 4min-6min to make all the raw materials fully mixed, form a concrete mixture; S1.4, pouring forming: the mixed concrete is poured into the slope mold, the vibrator is used, the vibration frequency is adjusted to 6000 times / min-10000 times / min, the concrete is compacted, the internal air is discharged, and the preliminary formed anti-scouring slope ecological concrete is obtained; S1.5, curing: the formed concrete is cured, and water is sprayed 3-4 times a day to keep the concrete surface wet, and the anti-scouring slope ecological concrete is obtained.

4. The erosion-resistant revetment eco-concrete formulation according to claim 3, wherein, In S1.1, the speed of the mixer dry mixing is 60r / min-100r / min, and the mixing time is 2-3min.

5. The erosion control, revetment, eco-concrete formulation of claim 3, wherein, In S1.5, the curing is carried out in an environment with a temperature of 20±2℃ and a relative humidity of greater than 90%, and the curing time is 28 days-46 days.

6. The erosion control, revetment, and ecological concrete formulation of claim 1, wherein, In S2.1, the amount of the crop straw and the starch-based hydrogel is 5:

2.

7. The erosion control, revetment, eco-concrete formulation of claim 1, wherein, The crosslinking agent is N,N'-methylene bisacrylamide; and the initiator is potassium persulfate.

8. The erosion-resistant revetment eco-concrete formulation according to claim 7, characterized in that, The amount of the corn starch is 200g; the amount of the acrylamide is 100g; the amount of the N,N'-methylene bisacrylamide is 2g; the amount of the potassium persulfate is 1g; and the amount of the deionized water is 1000ml.

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