A lignin fiber lightweight high-strength ceramsite concrete and its preparation method

Abstract

This application relates to the field of concrete technology, specifically disclosing a lignin fiber lightweight high-strength expanded clay concrete and its preparation method. The preparation method of lignin fiber lightweight high-strength expanded clay concrete includes the following steps: soaking expanded clay in water for wetting treatment; adding lightweight materials to the wetting expanded clay and mixing evenly to obtain lightweight expanded clay; mixing the lightweight expanded clay and crack-resistant fibers to obtain a preliminary mixture, wherein the crack-resistant fibers include lignin fibers, quaternary ammonium salt preservatives, and organic amine preservatives; mixing and stirring cement, natural sand, water-reducing agent, and cenospheres to obtain a secondary mixture; and stirring the preliminary mixture and the secondary mixture to obtain lignin-based lightweight high-strength expanded clay concrete. The expanded clay concrete of this application has the advantages of being lightweight and high-strength; furthermore, the preparation method of this application has the advantages of improving the tensile strength and toughness of expanded clay concrete and reducing its high brittleness.

Description

Technical Field

[0001] This application relates to the field of concrete technology, specifically to a lignin fiber lightweight high-strength ceramsite concrete and its preparation method. Background Technology

[0002] Lightweight aggregate concrete, also known as expanded clay concrete, is concrete made by using expanded clay instead of gravel as the aggregate in concrete. It is 20-30% lighter than ordinary crushed stone concrete and has the functions of being lightweight and high-strength, heat-insulating, earthquake-resistant and fire-resistant. It also has the characteristics of being economical, energy-saving and environmentally friendly, and having a wide range of applications. It is widely used in high-rise buildings, bridge deck paving, and precast box girder construction.

[0003] However, due to the difficulty in resolving the contradiction between lightweight and high strength, a major problem remains in the application of lightweight aggregate concrete in Chinese engineering: the high brittleness of lightweight high-strength ceramsite concrete.

[0004] To address the aforementioned issues, the inventors proposed a lignin fiber lightweight high-strength ceramsite concrete with lower brittleness and higher tensile strength. Summary of the Invention

[0005] In order to effectively improve the tensile strength and toughness of lightweight high-strength ceramsite concrete and reduce the high brittleness of concrete, this application provides lignin fiber lightweight high-strength ceramsite concrete and its preparation method.

[0006] In a first aspect, this application provides a method for preparing lignin fiber lightweight high-strength ceramsite concrete, employing the following technical solution, including the following steps: (by weight parts)

[0007] Soak 400-800 parts of ceramsite in water and moisten for 10-16 hours;

[0008] Add 100-200 parts of lightweight material to the moistened ceramsite, mix well, and you will get lightweight ceramsite.

[0009] The lightweight ceramsite is mixed with 3-10 parts of crack-resistant fiber to obtain a preliminary mixture. The crack-resistant fiber includes lignin fiber, quaternary ammonium salt preservative and organic amine preservative in a mass ratio of (80-120):(1-10):(0.5-5).

[0010] Mix 600-1200 parts of cement, 80-160 parts of natural sand, 5.5-6.5 parts of water-reducing agent and 60-90 parts of cenospheres for 2.0-8.0 minutes to obtain a medium-strength mixture;

[0011] The initial mixture and the intermediate mixture are stirred for 2.0 min to 8.0 min to obtain lignin-based lightweight high-strength ceramsite concrete.

[0012] By adopting the above technical solution, adding lightweight materials after wetting the ceramsite helps to reduce the quality of ceramsite concrete.

[0013] Adding crack-resistant fibers to expanded clay aggregate can create more connection points inside the expanded clay concrete, forming a tight internal network structure. This enhances the toughness of the expanded clay concrete, improves its ductility, tensile strength, and impact resistance, effectively prevents cracking during use, and helps to enhance the overall strength of the expanded clay concrete.

[0014] The surface of lignin fiber has high activity, which can form a mechanical lock with the surface of ceramsite, thereby enhancing the bonding force between particles, helping to reduce internal defects and cracks in the material, and improving the overall strength of the material. Lignin fiber is an environmentally friendly plant fiber with advantages such as light weight, heat and water retention, and impermeability, while also being economical, energy-saving and environmentally friendly. Quaternary ammonium salts and organic amines are both organic preservatives that can effectively inhibit the growth and reproduction of microorganisms in lignin fiber, thereby preventing lignin fiber from being eroded and damaged by microorganisms, thus extending the service life of lignin fiber. The simultaneous use of two different organic preservatives can produce a synergistic effect, thereby enhancing the overall anti-corrosion effect.

[0015] Optionally, the lightweight material includes fly ash and silica fume in a mass ratio of (0.5-2.5):(0.5-1.5).

[0016] By adopting the above technical solution, adding fly ash and silica fume with smaller particle size to ceramsite can refine the diameter of individual grains, increase the relative area of ​​grain boundaries, help to hinder dislocation movement, improve the yield strength of the material, and the grain refinement can also reduce the dislocation density dispersed in each grain, allowing the material to undergo greater plastic deformation.

[0017] Optionally, the amount of lignin fiber used is 0.1%-0.5% of the total weight of the concrete raw materials.

[0018] By adopting the above technical solution, when the amount of lignin fiber is 0.1%-0.5% of the total weight of concrete raw materials, the crack resistance, wear resistance, impact resistance, flexibility and stability of concrete can be significantly improved.

[0019] Optionally, the ceramsite is pretreated as follows before wetting: 40-80 parts by weight of ZrO2 particles are added to the ceramsite, and after mixing, the mixture is heated to 1300℃-1400℃ and calcined for 1-4 hours.

[0020] By adopting the above technical solution, ZrO2 particles can undergo a phase transformation reaction during high-temperature sintering. Through the phase transformation of ZrO2 particles, on the one hand, new fracture surfaces are generated to absorb energy, and on the other hand, the volume expansion during the phase transformation absorbs energy. At the same time, the compressive stress generated by the volume expansion on the crack will hinder the crack propagation, which is beneficial to enhancing the toughness and strength of the ceramsite and reducing the high brittleness of concrete.

[0021] Optionally, the method for preparing the crack-resistant fiber is as follows: the lignin fiber is soaked in a 0.3mol / L-0.6mol / L CuO solution for 20-24 hours, then washed with water and dried, and then ground for 10-15 minutes; then it is mixed evenly with the quaternary ammonium salt preservative and the organic amine preservative.

[0022] By employing the above technical solution, CuO solution, with its oxidizing properties, can chemically react and break lignin fibers. Lignin fibers are soaked in a 0.3mol / L-0.6mol / L CuO solution, washed, dried, and then ground to shorten them. Short fibers can better fill the pores in concrete, improving weak points. Furthermore, short fibers can block or prolong the crack propagation path, reduce stress concentration caused by external loads, and improve the flexural strength of concrete. This prevents long lignin fibers from being difficult to disperse evenly in concrete, agglomerating or clumping, resulting in poor workability. After oxidation with copper oxide, the surface roughness of the lignin fibers increases, as does the bonding force and interfacial strength with cement, ceramsite, and other raw materials, leading to increased density and compressive strength. Simultaneously, copper ions have a good inhibitory effect on fungi, and their use in combination with quaternary ammonium salts helps improve the anti-corrosion efficacy of quaternary ammonium salts, achieving good anti-corrosion effects with lower retention levels and reducing costs.

[0023] Optionally, the ceramsite is selected from one or more of shale ceramsite, clay ceramsite, and fly ash ceramsite.

[0024] By adopting the above technical solutions, shale ceramsite has the characteristics of being lighter and having higher adsorption, clay ceramsite has good economic practicality and adsorption performance, and fly ash ceramsite has light weight, heat insulation and fire resistance. Choosing a variety of ceramsite materials can make process design and construction more flexible and help to adapt to different engineering needs.

[0025] Optionally, the apparent density of the ceramsite is 1400-1700 kg / m³. 3 The cylinder compressive strength is 3-7 MPa.

[0026] By adopting the above technical solution, the apparent density is 1400-1700 kg / m³. 3 Ceramsite with a compressive strength of 3-7 MPa is lighter and has good compressive strength.

[0027] Optionally, the cenospheres have an apparent density of 0.6 × 10⁻⁶. 3 kg / m 3 -0.8×10 3 kg / m 3 Spherical fly ash particles.

[0028] By adopting the above technical solution, 0.6×10 3 kg / m 3 -0.8×10 3 kg / m 3 The fly ash spherical cenospheres are lighter, and the addition of fly ash helps to enhance the toughness of the ceramsite.

[0029] Optionally, the water-reducing agent may be a naphthalene-based water-reducing agent, a lignin sulfonate, or a water-soluble resin sulfonate.

[0030] By adopting the above technical solutions, naphthalene-based water-reducing agents, lignin sulfonate-based or water-soluble resin sulfonate-based water-reducing agents have abundant raw material sources, simple manufacturing processes, and low pollution, meeting environmental protection requirements. They can significantly reduce the amount of water required for concrete and improve the compressive strength and flexural strength of concrete.

[0031] Secondly, this application provides a lignin fiber lightweight high-strength ceramsite concrete, characterized in that it is made by a method for preparing lignin fiber lightweight high-strength ceramsite concrete.

[0032] By adopting the above technical solution, lightweight and high-strength ceramsite concrete can be obtained, and this ceramsite concrete has better ductility, higher tensile strength and toughness.

[0033] In summary, this application has the following beneficial effects:

[0034] 1. Adding crack-resistant fibers to concrete allows the internal micro-cracks to expand outward under external forces, forming a bridging structure across these cracks and preventing further expansion. Simultaneously, the addition of crack-resistant fibers alters the stress distribution within the concrete, making the stress more uniform, reducing stress concentration, inhibiting crack generation and propagation, and lowering the brittleness of the concrete.

[0035] 2. Adding ZrO2 particles to ceramsite and calcining them together causes the atoms between the ceramsite and ZrO2 particles to migrate and rearrange at high temperatures, forming a more stable crystal structure. This enhances the overall strength and hardness of the concrete, enabling it to better withstand external pressure and reducing its brittleness.

[0036] 3. By soaking and drying lignin fibers in CuO solution and then grinding them, the lignin fibers are sheared. The random distribution of short fibers can form a tighter bond with the aggregates and cement paste in the concrete, better fill the gaps between concrete particles, help reduce cracks and defects that may occur during the hardening process of concrete, and enhance the stability and crack resistance of concrete. Detailed Implementation

[0037] The following embodiments provide a further detailed description of this application.

[0038] Example

[0039] Example 1: A lignin fiber lightweight high-strength ceramsite concrete, the raw materials and their quantities are shown in Table 1, wherein the cement is PO32.5 silicate cement; the ceramsite is shale ceramsite with an average particle size of 15 mm and an apparent density of 1400 kg / m³. 3 The compressive strength of the cylinder is 7 MPa; the lightweight material is fly ash; the crack-resistant fiber is made of lignin fiber, quaternary ammonium salt preservative and organic amine preservative in a mass ratio of 100:1:0.5, the lignin fiber is 6 mm long and 20 μm in diameter, the quaternary ammonium salt preservative is dimethyldisdecylammonium chloride, and the organic amine preservative is dodecyl dimethylbenzylammonium chloride; the cenospheres have an apparent density of 0.7 × 10⁻⁶ MPa. 3 kg / m 3 The fly ash spherical cenospheres; the water-reducing agent was selected from Shandong Wanshan Chemical Co., Ltd., specification FDN-C, model jsj-122; the apparent density of the natural sand was 2410 kg / m³. 3 The particle size is 1.5 mm.

[0040] The method for preparing the lignin fiber lightweight high-strength ceramsite concrete includes the following steps:

[0041] S1. Soak the ceramsite in water for 12 hours to moisten it;

[0042] S2. Add lightweight material to the wetted ceramsite and mix evenly to obtain lightweight ceramsite.

[0043] S3. Mix the lightweight ceramsite with crack-resistant fibers to obtain the initial mixture;

[0044] S4. Mix cement, natural sand, water-reducing agent and cenospheres with water for 5.0 min to obtain intermediate mixture;

[0045] S5. Mix the initial mixture and the intermediate mixture for 8.0 min to obtain lignin-based lightweight high-strength ceramsite concrete.

[0046] Table 1. Raw materials and dosage of each raw material in Examples 1-4

[0047]

[0048]

[0049] Example 2: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 1 in that its raw materials and the amount of each raw material are shown in Table 1, while the remaining steps are the same as in Example 1.

[0050] Example 3: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 1 in that its raw materials and the amount of each raw material are shown in Table 1, while the remaining steps are the same as in Example 1.

[0051] Example 4: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 1 in that its raw materials and the amount of each raw material are shown in Table 1, while the remaining steps are the same as in Example 1.

[0052] Example 5: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 1 in that the lightweight materials include fly ash and silica fume in a mass ratio of 2:1, and the remaining steps are the same as in Example 1.

[0053] Example 6: A lignin fiber lightweight high-strength expanded clay aggregate concrete, which differs from Example 1 in that the expanded clay aggregate is pretreated as follows before being soaked in water in step S1: 40 kg of ZrO2 particles are added to 800 kg of expanded clay aggregate, mixed and then heated to 1300℃ and calcined for 2 hours. The remaining steps are the same as in Example 1.

[0054] Example 7: A lignin fiber lightweight high-strength expanded clay concrete, which differs from Example 6 in that 80 kg of ZrO2 particles are added to 800 kg of expanded clay, and after mixing, the mixture is heated to 1300℃ and calcined for 3 hours. The remaining steps are the same as in Example 6.

[0055] Example 8: A lightweight high-strength ceramsite concrete with lignin fiber, which differs from Example 1 in that the lignin fiber is made by the following method: the lignin fiber is soaked in a 0.4 mol / L CuO solution for 20 h, then washed with water and dried, and then ground for 10 min. It is then mixed evenly with quaternary ammonium salt preservative and organic amine preservative. The remaining steps are the same as in Example 1.

[0056] Example 9: A lightweight high-strength ceramsite concrete with lignin fiber, which differs from Example 8 in that the lignin fiber is not ground for 10 minutes after washing and drying, while the other steps are the same as in Example 8.

[0057] Example 10: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 1 in that the ceramsite includes shale ceramsite, clay ceramsite and fly ash ceramsite in a mass ratio of 1:1:1. The remaining steps are the same as in Example 1.

[0058] Example 11: A lignin fiber lightweight high-strength expanded clay aggregate concrete, which differs from Example 5 in that the expanded clay aggregate is pretreated as follows before being soaked in water in step S1: 80 kg of ZrO2 particles are added to 800 kg of expanded clay aggregate, mixed, and then heated to 1300℃ and calcined for 3 hours. The remaining steps are the same as in Example 5.

[0059] Example 12: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 5 in that the lignin fiber is made by the following method: the lignin fiber is soaked in a 0.4 mol / L CuO solution for 20 h, then washed with water and dried, and then ground for 10 min. It is then mixed evenly with quaternary ammonium salt preservative and organic amine preservative. The remaining steps are the same as in Example 5.

[0060] Example 13: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 7 in that the lignin fiber is soaked in a 0.4 mol / L CuO solution for 20 h, then washed with water and dried, and then ground for 10 min. It is then mixed evenly with quaternary ammonium salt preservative and organic amine preservative. The remaining steps are the same as in Example 7.

[0061] Example 14: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 13 in that the lightweight materials include fly ash and silica fume in a mass ratio of 2:1, and the ceramsite includes shale ceramsite, clay ceramsite and fly ash ceramsite in a mass ratio of 1:1:1. The remaining steps are the same as in Example 13.

[0062] Comparative Example

[0063] Comparative Example 1: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 1 in that the amount of crack-resistant fiber added is 0, while the remaining steps are the same as in Example 1.

[0064] Comparative Example 2: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 1 in that the amount of crack-resistant fiber added is 20 kg, and the remaining steps are the same as in Example 1.

[0065] Comparative Example 3: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 1 in that no quaternary ammonium salt preservatives or organic amine preservatives are added to the crack-resistant fibers, while the remaining steps are the same as in Example 1.

[0066] Comparative Example 4: A lignin fiber lightweight high-strength ceramsite concrete, which differs from Example 1 in that the amount of organic amine preservative added to its crack-resistant fiber is 0, and the remaining steps are the same as in Example 1.

[0067] Comparative Example 5: A method for preparing lightweight, high-strength ceramsite concrete is as follows:

[0068] S1. After pre-wetting 445kg of coarse aggregate, air dry it until the surface is dry and the inside is saturated with water.

[0069] S2. Mix the coarse aggregate treated in S1 with 607 kg of fine aggregate and stir for 90 seconds.

[0070] S3. Add 445 kg of cementitious material to the mixture after S2 treatment and stir for 30 seconds;

[0071] S4. Slowly add the aqueous solution prepared by adding 10 kg of polycarboxylate superplasticizer to the mixture after mixing in S3, and stir for 60 seconds to obtain lightweight high-strength ceramsite concrete.

[0072] The cementitious materials include 400 kg of cement and 45 kg of ultrafine modified fly ash;

[0073] The coarse aggregate includes 445 kg of fly ash ceramsite;

[0074] The fine aggregate consists of 217 kg of slag and 390 kg of river sand; the volume of the slag accounts for 50% of the total volume of the fine aggregate.

[0075] The amount of admixture is 2.2 wt% of the cementitious material.

[0076] Performance testing

[0077] Test Example 1

[0078] The concrete specimens prepared in Examples 1-14 and Comparative Examples 1-4 were subjected to tests for compressive strength, tensile strength and apparent density. Each test was divided into three groups, and the average value of the test results of the three groups was recorded as the final result in Table 2.

[0079] The compressive strength was tested in accordance with GB / T 50081-2002 "Standard for Test Method of Compressive Strength of Concrete"; the tensile strength was tested in accordance with GB / T 50082-2009 "Standard for Test Method of Tensile Strength of Concrete"; and the apparent density was tested in accordance with GB / T 50080-2016 "Standard for Test Method of Performance of Ordinary Concrete Mixture".

[0080] Table 2. Test data for compressive strength, tensile strength, and apparent density.

[0081]

[0082]

[0083] Results analysis:

[0084] The test data from Examples 1-14 and Comparative Examples 1-5 show that the compressive strength of the concrete in this application is above 34.1 MPa, the tensile strength is above 2.45 MPa, and the highest apparent density is 1454 kg / m³, as obtained in Example 2. 3 The apparent density of traditional ceramsite concrete is 1710 kg / m³. 3 The apparent density of the expanded clay concrete prepared by this invention is reduced by 15% compared with that of ordinary expanded clay concrete, and the tensile strength and compressive strength are also improved compared with traditional expanded clay concrete. Therefore, the expanded clay concrete prepared by this application is lighter, with improved strength and brittleness resistance, and better overall performance.

[0085] Performance test data from Examples 1-5 and Comparative Examples 1-2 show that the addition of crack-resistant fibers reduces the brittleness of concrete and effectively improves its overall performance. In Example 1, when the amount of crack-resistant fibers added was 0.38% of the total weight of the concrete raw materials, the concrete specimens exhibited the highest compressive and tensile strength values, demonstrating the best toughness and resistance to brittleness. Crack-resistant fibers provided the optimal improvement to the overall performance of the concrete. However, excessive addition of crack-resistant fibers increased the number of interfaces between the fibers and the cement matrix, leading to an increase in weak points within the concrete. This increase reduces the compressive strength of the concrete because the increased number of weak points negates the fiber reinforcement effect.

[0086] Performance test data from Examples 1 and 5 show that adding a mixture of fly ash and silica fume to ceramsite as a lightweight material, with the combined use of fly ash and silica fume, has a more significant effect on improving the plasticity and crack resistance of concrete than adding fly ash alone.

[0087] Performance test data from Examples 1 and 6-7 show that when ceramsite and ZrO2 particles are calcined, the ZrO2 particles undergo a phase transformation reaction, which causes them to expand in volume and generate new fracture surfaces, thus absorbing energy. The compressive stress on the cracks caused by the volume expansion during the phase transformation hinders crack propagation and enhances the strength and brittleness resistance of the ceramsite.

[0088] Performance test data from Examples 1 and 8-9 show that when lignin fibers are soaked and dried in CuO solution before grinding, the lignin fibers undergo a chemical reaction after being soaked in the oxidizing CuO solution, making them easier to shear. Grinding promotes the shearing of lignin fibers. Short fibers mixed with ceramsite exhibit better toughening and reinforcing properties. The shearing effect of lignin fibers in unground concrete is slightly worse.

[0089] The performance test data from Examples 1 and 10 show that the mixture of various types of expanded clay aggregate has no significant effect on the tensile and compressive strength of concrete. The mixture of various types of expanded clay aggregate further reduces the apparent density of concrete, making it lighter.

[0090] Performance test data from Examples 5-7 and Examples 11-13 show that lightweight materials include three pretreatment methods: fly ash and silica fume in a mass ratio of 2:1, calcination of ceramsite and ZrO2 particles, and soaking and grinding lignin fibers in CuO solution. Any combination of these two methods is beneficial for concrete to exhibit better toughness and strength.

[0091] Test Example 2

[0092] S1. After curing the concrete test blocks prepared in Examples 1, 8-9 and Comparative Examples 3-4 for 28 days, they were taken out from the standard curing room, dried and ice-cooled, and then tested for compressive strength. Three test blocks were taken from each group, and the average value was recorded in Table 3.

[0093] S2. After curing the concrete test blocks prepared in Examples 1, 8-9 and Comparative Examples 3-4 for 28 days, they were taken out from the standard curing room and placed in a 50 mg / mL Na2SO4 solution for durability testing by full immersion. The test ages were 60 days, 180 days and 300 days, respectively. After immersion, the test blocks were dried and cooled before compressive strength testing. Three test blocks were taken from each group, and the average value was recorded in Table 3.

[0094] All tests in this experiment were conducted in accordance with the international standard GB / T 50081-2002 "Standard for Test Method of Compressive Strength of Concrete".

[0095] Table 3 Compressive strength (MPa) of concrete at different ages

[0096]

[0097] Results analysis:

[0098] Analysis of the experimental data from Example 1 and Comparative Examples 3-4 shows that adding quaternary ammonium salt preservatives or organic amine preservatives to crack-resistant fibers can effectively inhibit the growth and reproduction of microorganisms in lignin fibers, prevent lignin fibers from being eroded and damaged by microorganisms, extend the service life of lignin fibers, and thus maintain the good performance of concrete. Moreover, the combined anti-corrosion effect of quaternary ammonium salt preservatives and organic amine preservatives is better than the anti-corrosion effect of using one of the preservatives alone.

[0099] Analysis of the experimental data from Examples 1 and 8-9 shows that Cu... + It has a good inhibitory effect on fungi, Cu+ When used in combination with quaternary ammonium salts, it helps to improve the anti-corrosion efficacy of quaternary ammonium salts, achieving better anti-corrosion effects at a lower retention level.

[0100] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing lignin fiber lightweight high-strength ceramsite concrete, characterized in that, Includes the following steps: by weight, Soak 400-800 parts of ceramsite in water and moisten for 10-16 hours; Add 100-200 parts of lightweight material to the moistened ceramsite, mix well, and you will get lightweight ceramsite. The lightweight ceramsite is mixed with 3-10 parts of crack-resistant fiber to obtain a preliminary mixture. The crack-resistant fiber includes lignin fiber, quaternary ammonium salt preservative and organic amine preservative in a mass ratio of (80-120):(1-10):(0.5-5). Mix 600-1200 parts of cement, 80-160 parts of natural sand, 5.5-6.5 parts of water-reducing agent, 60-90 parts of cenospheres and 100-120 parts of water for 2.0-8.0 minutes to obtain a medium-strength mixture. The initial mixture and the intermediate mixture are stirred for 2.0 min to 8.0 min to obtain lignin-based lightweight high-strength ceramsite concrete.

2. The method for preparing lignin fiber lightweight high-strength ceramsite concrete according to claim 1, characterized in that: The lightweight material comprises fly ash and silica fume in a mass ratio of (0.5-2.5):(0.5-1.5).

3. The method for preparing lignin fiber lightweight high-strength ceramsite concrete according to claim 1, characterized in that: The amount of lignin fiber used is 0.1%-0.5% of the total weight of the concrete raw materials.

4. The method for preparing lignin fiber lightweight high-strength ceramsite concrete according to claim 1, characterized in that, Before wetting, the ceramsite is pretreated as follows: 40-80 parts by weight of ZrO2 particles are added to 400-800 parts by weight of ceramsite, and after mixing, the mixture is heated to 1300℃-1400℃ and calcined for 1-4 hours.

5. The method for preparing lignin fiber lightweight high-strength ceramsite concrete according to claim 1, characterized in that, The method for preparing the crack-resistant fiber is as follows: the lignin fiber is soaked in a 0.3mol / L-0.6mol / L CuO solution for 20-24 hours, then washed with water and dried, and then ground for 10-15 minutes; then it is mixed evenly with the quaternary ammonium salt preservative and the organic amine preservative.

6. The method for preparing lignin fiber lightweight high-strength ceramsite concrete according to claim 1, characterized in that: The ceramsite is selected from one or more of shale ceramsite, clay ceramsite, and fly ash ceramsite.

7. The method for preparing lignin fiber lightweight high-strength ceramsite concrete according to claim 1, characterized in that: The apparent density of the ceramsite is 1400-1700 kg / m³. 3 The cylinder compressive strength is 3-7 MPa.

8. The method for preparing lignin fiber lightweight high-strength ceramsite concrete according to claim 1, characterized in that: The cenospheres have an apparent density of 0.6 × 10⁻⁶. 3 kg / m 3 -0.8×10 3 kg / m 3 Spherical fly ash particles.

9. The method for preparing lignin fiber lightweight high-strength ceramsite concrete according to claim 1, characterized in that: The water-reducing agent is a naphthalene-based water-reducing agent, a lignin sulfonate, or a sulfonate.

10. A lignin fiber lightweight high-strength ceramsite concrete, characterized in that, It is prepared by the method for preparing lignin fiber lightweight high-strength ceramsite concrete according to any one of claims 1-9.

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