Cement-based composite material based on bionic structure and preparation method thereof

Abstract

The invention provides a cement-based composite material based on a bionic structure and a preparation method thereof, and belongs to the field of building materials.The cement-based composite material comprises a plurality of cement slurry layers and a plurality of non-metal continuous fiber layers which are alternately stacked layer by layer; steel fibers are mixed in the cement slurry layers, and the steel fibers in the same cement slurry layer are arranged in the same direction; the non-metal continuous fibers in each non-metal continuous fiber layer are arranged in the same direction; and the projection included angle theta between the steel fibers in any cement slurry layer and the nonmetal continuous fibers in the adjacent nonmetal continuous fiber layer meets the following condition: 5 degrees is greater than or equal to theta. A discontinuous fiber stacking structure is improved, a rigid discontinuous steel fiber and flexible non-metal continuous fiber alternate stacking structure is adopted, and a bionic structure is formed through precise pouring forming, so that the cement-based composite material has ultrahigh tensile strength and strain performance.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a cement-based composite material based on a bionic structure and a preparation method thereof. Background Art

[0002] The number, breadth, and geographic scope of strategically important engineering projects, such as cross-sea tunnels, plateau railways, plateau hydropower stations, and infrastructure in seismic zones, are constantly expanding. The long-term, safe service of infrastructure critical to national needs will face increasingly complex loads, harsher environments, and more extreme application scenarios. These challenges pose challenges to the development of building materials. Reinforced concrete structures can improve their flexural strength to some extent. However, due to the inherent brittleness of concrete, frequent cracks pose significant operational risks and incur significant maintenance costs. Therefore, improving concrete's tensile strength and strain resistance can significantly enhance the durability and safety of structures, extending their service life.

[0003] Conventional concrete has a tensile strength of less than 8 MPa and a strain of less than 0.005%. Ultra-high-performance concrete (UHPC) has a tensile strength of 8-18 MPa and a strain of ≤0.5%, which improves the tensile strength of concrete to a certain extent, but the strain is low, making it prone to forming large, isolated cracks. Engineering cement-based composites (ECC) have a strain of 1%-7%, but due to their low tensile strength of 3-10 MPa, they are not suitable for high-intensity, complex loads, harsher environments, or more extreme applications.

[0004] Therefore, it is of great significance to develop a cement-based composite material with excellent tensile strength and strain properties. Summary of the Invention

[0005] In view of the technical problems existing in the background technology, the present invention provides a cement-based composite material based on a bionic structure and a preparation method thereof, aiming to solve the technical problem of simultaneously improving the tensile strength and strain properties of cement-based materials.

[0006] In a first aspect, the present invention provides a cement-based composite material based on a bionic structure, comprising a plurality of cement slurry layers and a plurality of non-metallic continuous fiber layers alternately stacked layer by layer; steel fibers are mixed in the cement slurry layers, and the steel fibers in the same cement slurry layer are arranged in the same direction; the non-metallic continuous fibers in each non-metallic continuous fiber layer are arranged in the same direction; and the projected angle θ between the steel fibers in any cement slurry layer and the non-metallic continuous fibers in its adjacent non-metallic continuous fiber layer satisfies the following condition: 5° ≥ |θ|.

[0007] Preferably, the cement-based composite material includes the following raw materials by weight: 70-100 parts of cement, 0-30 parts of auxiliary cementitious materials, 0-130 parts of fine aggregate, 0.08-3 parts of water reducer, 14-25 parts of water, 5-20 parts of steel fiber, and 1.5-15 parts of non-metallic continuous fiber.

[0008] Preferably, the diameter of the steel fiber is 0.05-0.3 mm, the length of the steel fiber is 5-30 mm, and the tensile strength of the steel fiber is ≥2000 MPa.

[0009] Preferably, the diameter of the non-metallic continuous fiber is 0.01-0.03 mm, and the tensile strength of the non-metallic continuous fiber is ≥2000 MPa. In the present invention, the length of the non-metallic continuous fiber is not limited and can be selected by those skilled in the art based on mold size or sample size requirements.

[0010] Preferably, the non-metallic continuous fiber includes at least one of PP fiber, PE fiber, aramid fiber and carbon fiber.

[0011] Preferably, the auxiliary cementitious materials include ultrafine mineral powder and silica fume.

[0012] In the present invention, the ultrafine mineral powder and silica fume can be mixed in any proportion.

[0013] Preferably, the SiO2 content of the silica fume is ≥90%; the specific surface area of ​​the silica fume is ≥10,000 m 2 / kg.

[0014] Preferably, the activity grade of the ultrafine mineral powder is S95 or above; the specific surface area of ​​the ultrafine mineral powder is ≥500m² / kg.

[0015] Preferably, the cement is ordinary Portland cement with a strength grade of 32.5 or above.

[0016] Preferably, the fine aggregate includes at least one of machine-made sand, river sand, high-alumina aggregate, and quartz sand; and the fineness modulus of the fine aggregate is 1.6 to 2.2.

[0017] Preferably, the water reducer is a polycarboxylate water reducer.

[0018] In a second aspect, the present invention provides a method for preparing a cement-based composite material based on a biomimetic structure, comprising the following steps: (1) Mix cement, auxiliary cementitious materials, fine aggregate, water reducer, water and steel fiber and stir them evenly to form cement slurry; (2) Spreading the cement slurry in the mold to obtain a cement slurry layer; (3) Laying the non-metallic continuous fibers on the cement slurry layer in the same direction to obtain a non-metallic continuous fiber layer; (4) Repeating steps (2) and (3) until a preset number of cement slurry layers are obtained by alternately stacking, and after the cement slurry hardens, demolding and curing are performed to obtain a cement-based composite material based on a biomimetic structure; The projected angle θ between the steel fibers in any cement slurry layer and the non-metallic continuous fibers in the adjacent non-metallic continuous fiber layer satisfies the following condition: 5°≥|θ|.

[0019] In the present invention, the projection angle θ refers to the projection angle θ between the steel fibers in any cement slurry layer and the non-metallic continuous fibers in its adjacent non-metallic continuous fiber layer on the bottom plane of the first cement slurry layer.

[0020] The principle of the technical solution of the present invention is: The Bouligand structure is composed of spirally stacked thin layers of unidirectional nanofibers. This structural organization is widely found in natural biological materials and exhibits excellent mechanical properties. The present invention uses common silicate cement as a base material and mimics the Bouligand structure by alternating discontinuous steel fibers and continuous polymer fibers. Through a specific configuration method and molding process (precision layered casting), the discontinuous steel fibers and continuous polymer fibers form a crossable structure. Steel fibers are rigid fibers that can ensure the high flexural and tensile strength of cement-based materials. Continuous non-metallic fibers are flexible fibers. A single non-metallic continuous fiber has a larger contact area with the cement matrix, which can more efficiently consume energy and disperse stress in brittle cement-based materials.

[0021] Compared with the prior art, the present invention has the following beneficial effects: Inspired by the nanoscale discontinuous stacking structure of biological shells, this invention improves upon the discontinuous fiber stacking structure by employing an alternating stacking structure of rigid discontinuous steel fibers and flexible non-metallic continuous fibers. This fully leverages the designability of cement-based composites. Using common Portland cement as the base material, the invention creates a biomimetic structure through precision casting, resulting in a cement-based composite with ultra-high tensile strength and strain resistance. Furthermore, the raw materials required for this invention are readily available and inexpensive, and high-temperature, high-pressure firing is not required. This biomimetic approach allows for the preparation of large-volume cement-based composites, promising promising applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the three-dimensional effect of the arrangement structure of the fiber material in the cement-based composite material in Example 2 of the present invention; Figure 2 This is a schematic top view of the fiber material arrangement structure in the cement-based composite material in Example 2 of the present invention. DETAILED DESCRIPTION

[0023] The following embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0024] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0025] In the following examples of the present invention, ultrafine mineral powder was purchased from Baowu Group Environmental Resources Technology Co., Ltd., with an activity grade of S95 and a specific surface area of ​​500m 2 / kg; silica fume was purchased from Hanyuan Zonghuili Environmental Protection Technology Co., Ltd., with a SiO2 content of ≥90% and a specific surface area of ​​15000 m 2 / kg; polycarboxylate water reducer was purchased from Suzhou Xingbang Chemical Building Materials Co., Ltd., with a water reduction rate of 35%.

[0026] The standard curing room curing conditions in the following embodiments of the present invention are: indoor ambient temperature is 20±2°C, and relative humidity is above 95%.

[0027] The method of inducing fiber orientation using an L-shaped directional casting device is as follows: first, the outlet of the horizontal channel of the L-shaped directional casting device is sealed, and the slurry is poured into the device from the vertical top. When the height of the concrete in the vertical container reaches a certain height, the obstruction of the horizontal channel is removed, and the slurry flows out from the outlet of the horizontal channel. The fibers are gradually oriented in this process. During molding, the specimen is cast layer by layer by the L-shaped device, and the thickness of each layer is approximately equal to the height of its horizontal channel. At the same time, the L-shaped device is moved from one end of the mold to the other end to achieve layer-by-layer casting in the same direction.

[0028] In the following examples, the total thickness of the samples is the same, and the thickness of each cement slurry layer is controlled according to the mold size.

[0029] Example 1 In this embodiment, the cement-based composite material based on the bionic structure has 15 cement slurry layers and 14 non-metallic continuous fiber layers.

[0030] A method for preparing a cement-based composite material based on a biomimetic structure comprises the following steps: (1) Take 100 parts of M325 cement and 0.08 parts of water reducer and mix them evenly. Add 14 parts of water and continue to stir. Then add 5 parts of steel fiber (diameter 0.3mm, length 30mm, tensile strength 2000MPa) and stir for 3 minutes to form a cement slurry to be poured. Prepare 15 parts of carbon fiber (diameter 0.01mm, tensile strength 3500MPa) for standby use. (2) Place the mold on a vibrating table, pour 1 / 15 of the cement slurry to be poured into the L-shaped directional pouring device, and pour it horizontally in the same direction on the bottom of the mold to obtain the first cement slurry layer L1; (3) 1 / 15 of the carbon fibers are evenly laid on the first cement slurry layer along the same direction (the projection angle θ with the steel fibers in the cement slurry layer in step (2) on the bottom plane of the first cement slurry layer is 0°) to obtain the first non-metallic continuous fiber layer N1; (4) Repeat step (2) with the pouring direction being the same as that of step (2) to obtain a second cement slurry layer L2; (5) When no bubbles emerge from the slurry surface, the same amount of carbon fiber as that in step (3) is evenly spread on the second cement slurry layer in the same direction (the same direction as step (3)) to obtain the second non-metallic continuous fiber layer N2; (6) Repeat steps (2) to (5) until the 15th cement slurry layer L is obtained by alternating layers. 15 , Cover the mold surface with plastic wrap and let it stand for 24 hours to allow the specimen to harden; (7) After the specimen has hardened, remove it from the mold and place it in a standard curing room for 28 days.

[0031] Example 2 In this embodiment, the cement-based composite material based on the bionic structure has 10 cement slurry layers and 9 non-metallic continuous fiber layers.

[0032] A method for preparing a cement-based composite material based on a biomimetic structure comprises the following steps: (1) Take 70 parts of PO525 cement, 29 parts of silica fume, 1 part of ultrafine mineral powder, 80 parts of quartz sand (fineness modulus 1.6), 30 parts of high-aluminum aggregate, and 2 parts of water reducer, mix them evenly, add 25 parts of water, continue to stir, then add 20 parts of steel fiber (diameter 0.3mm, length 30mm, tensile strength 2000MPa), stir for 3 minutes to form a cement slurry to be poured; prepare 1.5 parts of PE fiber (diameter 0.03mm, tensile strength 3200MPa) for standby use; (2) Place the mold on a vibrating table, pour 1 / 10 of the cement slurry to be poured into the L-shaped directional pouring device, and pour it horizontally in the same direction on the bottom of the mold to obtain the first cement slurry layer L1; (3) 1 / 10 of the PE fibers are evenly spread on the first cement slurry layer along the same direction (the projection angle θ with the steel fibers in the cement slurry layer in step (2) on the bottom plane of the first cement slurry layer is 0°) to obtain the first non-metallic continuous fiber layer N1; (4) Repeat step (2), with the pouring direction forming an angle of 5° with the pouring direction in step (2), to obtain a second cement slurry layer L2; that is, the projection angle θ between the steel fibers in the cement slurry layer and the non-metallic continuous fibers in the non-metallic continuous fiber layer N1 on the bottom plane of the first cement slurry layer is 5°; (5) When no bubbles emerge from the slurry surface, the same amount of PE fibers as in step (3) are evenly spread on the second cement slurry layer in the same direction (the same direction as in step (3)) to obtain the second non-metallic continuous fiber layer N2; (6) Repeat step (2), with the pouring direction forming an angle of 0° with the pouring direction in step (2), to obtain a third cement slurry layer L3; that is, the projection angle θ between the steel fibers in the cement slurry layer and the non-metallic continuous fibers in the non-metallic continuous fiber layer N2 on the bottom plane of the first cement slurry layer is 0°; (7) When no bubbles emerge from the slurry surface, the same amount of PE fibers as in step (3) are evenly spread on the third cement slurry layer in the same direction (the same direction as in step (3)) to obtain the third non-metallic continuous fiber layer N3; (8) Repeat step (2), and form a -5° angle between the pouring direction and the pouring direction in step (2) to obtain a fourth cement slurry layer L4; that is, the projection angle θ between the steel fibers in the cement slurry layer and the non-metallic continuous fibers in the non-metallic continuous fiber layer N3 on the bottom plane of the first cement slurry layer is -5°; (9) When no bubbles emerge from the slurry surface, the same amount of PE fibers as in step (3) are evenly spread on the fourth cement slurry layer in the same direction (the same direction as in step (3)) to obtain the fourth non-metallic continuous fiber layer N4; (10) Repeat steps (2) to (9) until the tenth cement slurry layer L is obtained by alternating layers. 10 , Cover the mold surface with plastic wrap and let it stand for 24 hours to allow the specimen to harden; (11) After the specimen has hardened, remove it from the mold and place it in a standard curing room for 28 days.

[0033] The schematic diagram of the three-dimensional effect of the fiber material arrangement structure in the cement-based composite material in this embodiment is as follows Figure 1 As shown, the top view effect diagram is as follows Figure 2 shown.

[0034] Example 3 In this embodiment, the cement-based composite material based on the bionic structure has 15 cement slurry layers and 14 non-metallic continuous fiber layers.

[0035] A method for preparing a cement-based composite material based on a biomimetic structure comprises the following steps: (1) Take 90 parts of PO425 cement, 9 parts of silica fume, 1 part of ultrafine mineral powder, 130 parts of river sand (fineness modulus 1.6), and 1.8 parts of water reducer, mix and stir evenly, add 23 parts of water, continue to stir evenly, then add 3 parts of steel fiber (diameter 0.05mm, length 5mm, tensile strength 2850MPa), stir for 3 minutes to form a cement slurry to be poured; prepare 5 parts of PP fiber (diameter 0.02mm, tensile strength 3450MPa) for standby use; (2) Place the mold on a vibrating table, pour 1 / 15 of the cement slurry to be poured into the L-shaped directional pouring device, and pour it horizontally in the same direction on the bottom of the mold to obtain the first cement slurry layer L1; (3) 1 / 15 of the PP fibers are evenly laid on the first cement slurry layer in the same direction (the same direction as in step (2), i.e., the projection angle θ with the steel fibers in the cement slurry layer in step (2) on the bottom plane of the first cement slurry layer is 0°) to obtain the first non-metallic continuous fiber layer N1; (4) Repeat step (2), with the pouring direction forming an angle of 5° with the pouring direction in step (2), to obtain a second cement slurry layer L2; that is, the projection angle θ between the steel fibers in the cement slurry layer and the non-metallic continuous fibers in the non-metallic continuous fiber layer N1 on the bottom plane of the first cement slurry layer is 5°; (5) When no bubbles emerge from the slurry surface, the same amount of PP fibers as in step (3) are evenly spread on the second cement slurry layer in the same direction (the same direction as in step (3)) to obtain the second non-metallic continuous fiber layer N2; (6) Repeat step (2), with the pouring direction forming an angle of -5° with the pouring direction in step (2), to obtain a third cement slurry layer L3; that is, the projection angle θ between the steel fibers in the cement slurry layer and the non-metallic continuous fibers in the non-metallic continuous fiber layer N2 on the bottom plane of the first cement slurry layer is -5°; (7) When no bubbles emerge from the slurry surface, the same amount of PP fibers as in step (3) are evenly spread on the third cement slurry layer in the same direction (the same direction as in step (3)) to obtain the third non-metallic continuous fiber layer N3; (8) Repeat steps (2) to (7) until the 15th cement slurry layer L is obtained by alternating layers. 15 , Cover the mold surface with plastic wrap and let it stand for 24 hours to allow the specimen to harden; (9) After the specimen has hardened, remove it from the mold and place it in a standard curing room for 28 days.

[0036] Comparative Example 1 A method for preparing a cement-based composite material comprises the following steps: (1) Take 70 parts of PO525 cement, 29 parts of silica fume, 1 part of ultrafine mineral powder, 80 parts of quartz sand (fineness modulus 1.6), 30 parts of high-aluminum aggregate, and 2 parts of water reducer, mix them evenly, add 25 parts of water, continue to stir, then add 20 parts of steel fiber (diameter 0.3 mm, length 30 mm, tensile strength 2000 MPa) and 1.5 parts of PE fiber (diameter 0.03 mm, tensile strength 3200 MPa), stir for 3 minutes to form the cement slurry to be poured; (2) Pour the cement slurry to be poured into the L-shaped directional pouring device, move it horizontally in the same direction, and pour it layer by layer until the mold is filled. Cover the surface with plastic wrap and let it stand for 24 hours to allow the specimen to harden; (3) After the specimen has hardened, remove it from the mold and place it in a standard curing room for 28 days.

[0037] Comparative Example 2 A method for preparing a cement-based composite material comprises the following steps: (1) Take 90 parts of PO425 cement, 9 parts of silica fume, 1 part of ultrafine mineral powder, 130 parts of river sand (fineness modulus 1.6), and 1.8 parts of water reducer, mix them evenly, add 23 parts of water, continue to stir evenly, then add 3 parts of steel fiber (diameter 0.05 mm, length 5 mm, tensile strength 2850 MPa) and 5 parts of PP fiber (diameter 0.02 mm, tensile strength 3450 MPa), stir for 3 minutes to form the cement slurry to be poured; (2) Place the mold on a vibrating table and slowly pour the slurry from one end, allowing the slurry to flow from the pouring end to the other end along the length direction until the mold is filled. Cover the surface with plastic wrap and let it stand for 24 hours to allow the specimen to harden; (3) After the specimen has hardened, remove it from the mold and place it in a standard curing room for 28 days.

[0038] Comparative Example 3 The difference between this comparative example and Example 2 is that the diameter of the PP fiber is 0.2 mm, which is 10 times larger than that of the PP fiber in Example 2. The remaining preparation steps are the same as those in Example 2.

[0039] Comparative Example 4 The difference between this comparative example and Example 2 is that both the steel fiber and the PP fiber are mixed in the cement slurry.

[0040] A method for preparing a cement-based composite material comprises the following steps: (1) Take 70 parts of PO525 cement, 29 parts of silica fume, 1 part of ultrafine mineral powder, 80 parts of quartz sand (fineness modulus 1.6), 30 parts of high-aluminum aggregate, and 2 parts of water reducer, mix them evenly, add 25 parts of water, continue to stir evenly, then add 20 parts of steel fiber (diameter 0.3mm, length 30mm) and 1.5 parts of PE fiber (diameter 0.03mm, tensile strength 3200MPa), stir for 3 minutes to form the cement slurry to be poured; (2) Place the mold on a vibrating table, pour 1 / 10 of the cement slurry to be poured into the L-shaped directional pouring device, and pour it horizontally in the same direction on the bottom of the mold; (3) Repeat step (2), with the pouring direction forming a 5° angle with the pouring direction in step (2); (4) Repeat step (2), with the pouring direction forming an angle of 0° with the pouring direction in step (2); (5) Repeat step (2), with the pouring direction forming a -5° angle with the pouring direction in step (2); (6) Repeat steps (2) to (5) until the mold is filled, cover the mold surface with plastic wrap, and let it stand for 24 hours to allow the specimen to harden; (7) After the specimen has hardened, remove it from the mold and place it in a standard curing room for 28 days.

[0041] The cement-based composite materials produced in the Examples and Comparative Examples were subjected to strength testing according to the "T / CBMF37-2018 T / CCPA 7-2018 Ultra-High Performance Concrete Basic Properties and Test Methods" (tensile specimens were bone-shaped, with a tensile cross-section of 50 mm × 50 mm). The tensile strength and tensile strain were measured sequentially. The test results are shown in Table 1.

[0042] Table 1

[0043] As can be seen from the table, the cement-based composites prepared in Examples 1, 2, and 3 exhibit significantly improved tensile strength and tensile strain compared to the cement-based composites prepared in Comparative Example 1 using the directional casting method and Comparative Example 2 using the conventional fiber-concrete mixed casting method. This demonstrates that the alternating stacking of rigid discontinuous steel fibers and flexible continuous non-metallic fibers significantly improves the tensile strength and tensile strain properties of concrete. The data from Example 2 and Comparative Example 3 demonstrate that the combination of coarser continuous PE fibers and steel fibers can improve the tensile strength of the cement-based composite to a certain extent, but the improvement in tensile strain is not significant.

[0044] The data from Example 2 and Comparative Example 4 show that mixing the continuous fibers with the slurry in advance does not significantly improve the tensile strength and tensile strain. This is because the early addition of the continuous fibers to the slurry is prone to agglomeration, disordered interweaving, and even disrupting the directional distribution of the steel fibers, making it difficult to form a bionic structure in which discontinuous steel fibers and flexible continuous non-metallic continuous fibers are alternately stacked. Therefore, the toughening effect is greatly reduced.

[0045] In summary, the performance of the bionic concrete prepared by this invention far surpasses that of existing concrete materials. This not only represents the successful combination of concrete's ultra-high strength and ultra-high toughness, but also marks the first time that ultra-high-performance cement-based bionic materials have been produced in large sizes, volumes, and with high quality. With this significant improvement in flexural properties, the application range of cement-based materials will expand unexpectedly.

[0046] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the present invention, other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A cement-based composite material based on a bionic structure, characterized in that: It comprises a plurality of cement slurry layers and a plurality of non-metallic continuous fiber layers alternately stacked layer by layer; the cement slurry layers are mixed with steel fibers; the steel fibers in the same cement slurry layer are arranged in the same direction; the non-metallic continuous fibers in each non-metallic continuous fiber layer are arranged in the same direction; and the projected angle θ between the steel fibers in any cement slurry layer and the non-metallic continuous fibers in its adjacent non-metallic continuous fiber layer satisfies the following condition: 5° ≥ |θ|.

2. The cement-based composite material based on biomimetic structure according to claim 1, characterized in that: The cement-based composite material includes the following raw materials in parts by weight: 70-100 parts of cement, 0-30 parts of auxiliary cementitious materials, 0-130 parts of fine aggregate, 0.08-3 parts of water reducer, 14-25 parts of water, 5-20 parts of steel fiber, and 1.5-15 parts of non-metallic continuous fiber.

3. The cement-based composite material based on biomimetic structure according to claim 1, characterized in that: The diameter of the non-metallic continuous fiber is 0.01-0.03 mm, and the tensile strength of the non-metallic continuous fiber is ≥2000 MPa.

4. The cement-based composite material based on biomimetic structure according to claim 3, characterized in that: The non-metallic continuous fiber includes at least one of PP fiber, PE fiber, aramid fiber and carbon fiber.

5. The cement-based composite material based on biomimetic structure according to claim 1, characterized in that: The diameter of the steel fiber is 0.05-0.3 mm, the length of the steel fiber is 5-30 mm, and the tensile strength of the steel fiber is ≥2000 MPa.

6. The cement-based composite material based on biomimetic structure according to claim 2, characterized in that: The auxiliary gelling materials include ultrafine mineral powder and silica fume.

7. The cement-based composite material based on biomimetic structure according to claim 6, characterized in that: The activity level of the ultrafine mineral powder is S95 or above, and the SiO2 content of the silica fume is ≥90%.

8. The cement-based composite material based on biomimetic structure according to claim 2, characterized in that: The fine aggregate includes at least one of machine-made sand, river sand, high-aluminum aggregate, and quartz sand.

9. The method for preparing a cement-based composite material based on a biomimetic structure according to any one of claims 1 to 8, wherein: The following steps are involved: (1) Mix cement, auxiliary cementitious materials, fine aggregate, water reducer, water and steel fiber and stir them evenly to form cement slurry; (2) Spreading the cement slurry in the mold to obtain a cement slurry layer; (3) Laying the non-metallic continuous fibers on the cement slurry layer in the same direction to obtain a non-metallic continuous fiber layer; (4) Repeating steps (2) and (3) until a predetermined number of cement slurry layers are obtained by alternately stacking, and after the cement slurry hardens, demolding and curing are performed to obtain a cement-based composite material based on a biomimetic structure; Wherein, the projected angle θ between the steel fibers in any cement slurry layer and the non-metallic continuous fibers in the adjacent non-metallic continuous fiber layer satisfies the following condition: 5°≥|θ|.

10. The method for preparing a cement-based composite material based on a biomimetic structure according to claim 9, characterized in that: The curing conditions are as follows: temperature is 18-25°C, humidity is greater than 95%, and curing time is 26-30 days.

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