A method for preparing ultra high performance concrete material using special fiber

Abstract

The application relates to the technical field of concrete materials, and discloses a method for preparing a new super high performance concrete material by using special fibers, which comprises the following method steps: S1, raw material preparation: preparing wood ash, special fibers, cement, mineral admixtures, fine aggregates, coarse aggregates, a water reducing agent and water; S2, raw material pretreatment: grinding the wood ash to perform refinement treatment; S3, mixing and stirring: adding the cement, the mineral admixtures, the fine aggregates and the coarse aggregates into a stirrer, adding the treated wood ash and the special fibers after dry mixing for a certain time, continuously stirring until uniform, and then adding the water and the water reducing agent to continuously stir; and S4, forming and curing: pouring the stirred concrete into a mold. Through a specific preparation process, the cement, the mineral admixtures and the specially treated wood ash are used in a synergistic manner to provide high compressive strength and flexural strength for the concrete, so that the concrete has good performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete materials, in particular to a method for preparing ultra-high performance concrete material by using special fibers. BACKGROUND

[0002] With the continuous development of the construction industry, the performance requirements of concrete materials are becoming higher and higher. Traditional concrete has problems such as low strength and poor durability, and it is difficult to meet the needs of modern construction engineering. Therefore, it is of great practical significance to develop ultra-high performance concrete materials.

[0003] Ultra-high performance concrete (UHPC) is a new type of cement-based composite material with ultra-high strength, high durability and excellent workability, which is usually composed of cement, silica fume, quartz sand, high-efficiency water reducing agent, steel fiber and other materials. It has high compressive strength, which is several times that of ordinary concrete. At the same time, it has excellent impermeability, frost resistance, chemical corrosion resistance and wear resistance, and can maintain good performance in harsh environmental conditions for a long time.

[0004] With the increasing demand for sustainable development and environmentally friendly building materials, finding alternatives to traditional building materials such as composite fibers has become a research hotspot. Bamboo fiber, as a renewable, biodegradable and high-strength natural resource, has shown great potential in replacing traditional reinforcing fibers.

[0005] Therefore, the present application aims to provide a method for preparing ultra-high performance concrete material by using special fibers, which adds bamboo fiber as a new material to ultra-high performance concrete to improve its mechanical properties, durability and environmental friendliness. SUMMARY

[0006] In view of the shortcomings of the prior art, the present application provides a method for preparing ultra-high performance concrete material by using special fibers, which solves the problems of high cost of traditional reinforcing fibers and certain limitations in environmental protection.

[0007] To achieve the above purpose, the present application realizes the following technical scheme: a method for preparing ultra-high performance concrete material by using special fibers, comprising the following method steps:

[0008] S1, raw material preparation: preparing wood ash, special fiber, cement, mineral admixture, fine aggregate, coarse aggregate, water reducing agent and water;

[0009] S2, raw material pretreatment: grinding the wood ash for fine treatment;

[0010] S3, mixing and stirring: cement, mineral admixture, fine aggregate, coarse aggregate are added into the mixer, after dry mixing for a certain time, the treated wood ash and special fiber are added, continue to stir until uniform, then add water and water reducing agent and continue to stir;

[0011] S4, forming and curing: the stirred concrete is poured into the mold for forming treatment, and the formed concrete is cured to obtain the ultra-high performance concrete material product.

[0012] Preferably, the raw materials are respectively: wood ash 50-85 parts, special fiber 15-75 parts, cement 420-480 parts, mineral admixture 110-145 parts, fine aggregate 120-150 parts, coarse aggregate 100-150 parts, water reducing agent 15-30 parts, and water 170-280 parts.

[0013] Preferably, the manufacturing method of the special fiber comprises the following steps:

[0014] Step one: the original bamboo is sawed and sliced, the length of the original bamboo slice is 10-40mm, and then the original bamboo slice is boiled in boiling water for 2-3h;

[0015] Step two: the boiled original bamboo slice is taken out and crushed into bamboo silk, and then the bamboo silk is soaked in sodium hydroxide solution;

[0016] Step three: the alkali-cooked bamboo fiber is soaked in a softener treatment solution;

[0017] Step four: the bamboo fiber prepared in step three is soaked in anhydrous ethanol, then washed with tap water, and naturally dried.

[0018] Preferably, in step two, the bath temperature is 100-110℃, the soaking time is 3-4h, and the bath ratio is 1:(25-30).

[0019] Preferably, in step three, the bath temperature is 45-55℃, the treatment time is 2-3h, and the bath ratio is 1:(25-30).

[0020] Preferably, in step S4, the formed concrete is cured for 15-20 days under the condition of temperature 25℃ and relative humidity 90%.

[0021] Preferably, the fine aggregate is quartz sand, river sand or machine-made sand, and the fineness modulus is between 2.4 and 2.8.

[0022] Preferably, the mineral admixture includes one or more of silica fume, fly ash, and slag powder.

[0023] Preferably, the cement is one of Portland cement, high belite cement, and sulphoaluminate cement.

[0024] Preferably, the wood ash after grinding has a fineness of 700-800 mesh, and the length of the special fiber is controlled in the range of 2-2.5 cm and the diameter is 0.1-0.5 mm.

[0025] The application provides a method for preparing super high performance concrete material by using special fiber.

[0026] 1. By the specific preparation process, the cement, mineral admixture and the wood ash treated specially are used to provide high compressive strength and flexural strength for the concrete, so that the concrete has good performance, the 30-day compressive strength can reach more than 200 MPa, and the one-week flexural strength is also significantly higher than that of ordinary concrete, which can meet the requirements of various high-performance engineering structures.

[0027] 2. By optimizing the mixing ratio of raw materials and adding water reducing agent, the concrete has certain fluidity during construction, which is convenient for pouring and forming, especially for complex-shaped structures and steel-intensive areas, the construction difficulty is reduced, and the wood ash is ground and added into the concrete, which not only realizes the recycling of waste and reduces the pollution to the environment, but also plays the potential activity of the wood ash, and the small particles of the wood ash can fill the pores in the concrete, improve the density of the concrete, and enhance the performance of the concrete.

[0028] 3. The special fiber made of raw bamboo through multiple processes is used, the length and diameter are controlled in a specific range, a three-dimensional network structure is formed in the concrete, the tensile strength and toughness of the concrete are significantly improved, the application of the natural fiber provides a green and sustainable solution for the reinforcement of the concrete, and since the concrete has a tight microstructure, the impermeability is much better than that of ordinary concrete. This makes the concrete effectively resist the penetration of water and other liquids in various harsh environments, such as moisture and chemical corrosion, thereby prolonging the service life of the concrete structure. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The preparation flowchart of the application is shown in the figure. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0031] Please refer to the drawings Figure 1The application provides a method for preparing ultra-high performance concrete material by using special fibers, comprising the following method steps:

[0032] S1, raw material preparation:

[0033] Wood ash as a unique ingredient has the potential to enhance the performance of concrete, 50 to 85 parts are prepared, special fibers are the key factor to improve the strength and toughness of concrete, 15 to 75 parts are prepared, cement as the main cementitious material, 420 to 480 parts are selected, one of which can be selected from Portland cement, high belite cement and sulphoaluminate cement, different types of cement have their own characteristics, which can provide a stable strength basis for concrete, mineral admixtures can improve the performance of concrete, which is composed of one or more of silica fume, fly ash and slag powder, a total of 110 to 145 parts, fine aggregate plays a role in filling and increasing the density of concrete, which is quartz sand, river sand or machine-made sand, the fineness modulus is strictly controlled between 2.4-2.8, 120 to 150 parts are prepared, coarse aggregate provides a skeleton support for concrete, 100 to 150 parts are prepared, water reducing agent can reduce the amount of water while maintaining the workability of concrete, 15 to 30 parts are prepared, the amount of water is 170 to 280 parts, and its quality also has an important influence on the performance of concrete.

[0034] S2, raw material pretreatment:

[0035] The wood ash is finely ground to achieve a fineness of 700 to 800 mesh. Through grinding, the particles of wood ash become smaller, which can better mix with other raw materials and fully exert its potential activity, thereby improving the performance of concrete. This pretreatment step is crucial for the strength and durability of the subsequent concrete.

[0036] S3, mixing and stirring:

[0037] Cement, mineral admixtures, fine aggregate and coarse aggregate are added to the high-efficiency mixer for dry mixing. In the dry mixing process, the ingredients are preliminarily mixed to lay the foundation for subsequent full combination. The dry mixing time is controlled within a certain range to ensure uniform distribution of the ingredients. After dry mixing, the pretreated wood ash and special fibers are added.

[0038] In this step, the special fiber manufacturing method is as follows:

[0039] First, the original bamboo is sawn and sliced, and the length of the original bamboo slice is controlled at 10 to 40 mm. Such length is convenient for subsequent processing and can play a good reinforcing role in concrete.

[0040] Next, the original bamboo slice is boiled in boiling water for 2 to 3 hours, and the boiling water boiling can remove impurities and part of lignin in the original bamboo slice, preparing for subsequent processing.

[0041] After the scouring of the raw bamboo pieces, they are crushed into bamboo filaments. The formation of bamboo filaments increases the surface area of the fibers, which is conducive to the combination with other ingredients. Then, the bamboo filaments are immersed in a sodium hydroxide solution for soaking. Under the conditions of a bath temperature of 100 to 110℃, an immersion time of 3 to 4h, and a bath ratio of 1:(25 to 30), the sodium hydroxide solution can further remove impurities and lignin in the bamboo filaments, improving the purity and strength of the fibers.

[0042] After the alkali cooking of the bamboo fibers, they are immersed in a softener treatment solution for soaking treatment. Under the conditions of a bath temperature of 45 to 55℃, a treatment time of 2 to 3h, and a bath ratio of 1:(25 to 30), the softener treatment solution can make the bamboo fibers more soft, reduce the friction between the fibers, and improve the workability of the concrete.

[0043] Finally, the treated bamboo fibers are soaked in anhydrous ethanol and then washed with tap water, and then naturally air-dried to obtain special fibers. The length of the special fibers is controlled in the range of 2 to 2.5cm, and the diameter is 0.1 to 0.5mm, which has good reinforcing effect and workability.

[0044] The fine particles of wood ash interact with other ingredients, and the special fibers form a three-dimensional network structure in the concrete, significantly improving the tensile strength and toughness of the concrete. Continue to stir to uniformly mix these ingredients, and then add water and a water reducing agent. The addition of the water reducing agent can reduce the water-cement ratio of the concrete, improve the density and strength of the concrete. During the stirring process, the stirring time and speed of each stage are carefully controlled to ensure the stability of the quality of the concrete.

[0045] S4, forming and curing

[0046] The stirred concrete is poured into a mold for forming treatment. During the pouring process, attention should be paid to controlling the pouring speed and method to avoid defects such as segregation and honeycomb. The formed concrete is cured under specific conditions. The curing temperature is 25℃, the relative humidity is 90%, and the curing time is 15 to 20 days. Such curing conditions can ensure that the concrete is fully hydrated, improving the strength and durability of the concrete. During the curing process, the concrete should be regularly inspected and maintained to ensure the stability of the curing conditions.

[0047] Through the above steps, the ultra-high performance concrete material prepared by using the special fibers has excellent performance and can be widely used in the fields of building, bridge, tunnel, etc.

[0048] The content of the present application will be further introduced in combination with specific examples.

[0049] Example 1:

[0050] A method for preparing an ultra-high performance concrete material using special fibers, comprising the following method steps:

[0051] S1, raw material preparation: preparing wood ash, special fiber, cement, mineral admixture, fine aggregate, coarse aggregate, water reducing agent and water;

[0052] S2, raw material pretreatment: grinding the wood ash for refinement treatment;

[0053] S3, mixing and stirring: adding cement, mineral admixture, fine aggregate, coarse aggregate into the mixer, after dry mixing for a certain time, adding treated wood ash and special fiber, continue to stir evenly, then add water and water reducing agent continue to stir;

[0054] S4, forming and curing: pouring the mixed concrete into the mold for forming treatment, the formed concrete is cured at a temperature of 25℃ and a relative humidity of 90% for 15 days, to obtain the finished product of ultra-high performance concrete material.

[0055] The raw materials are respectively: wood ash 85 parts, special fiber 75 parts, cement 420 parts, mineral admixture 110 parts, fine aggregate 120 parts, coarse aggregate 120 parts, water reducing agent 15 parts, water 180 parts, wherein the fine aggregate is quartz sand, river sand or machine-made sand, the fineness modulus is between 2.4-2.8, the mineral admixture includes one or more of silica fume, fly ash and slag powder, the cement is one of Portland cement, high belite cement and sulphoaluminate cement, the fineness of the ground wood ash is 700 mesh, the length of the special fiber is controlled in the range of 2cm, and the diameter is 0.5mm.

[0056] Further, in the present embodiment, the manufacturing method of the special fiber comprises the following steps:

[0057] Step one, cut the original bamboo into pieces, the length of the original bamboo piece is 15mm, then put the original bamboo piece into boiling water for 2h;

[0058] Step two, take out the cooked original bamboo piece, crush it into bamboo silk, then immerse the bamboo silk into sodium hydroxide solution for soaking, in this step, the bath temperature is 105℃, the immersion time is 4h, and the bath ratio is 1:25;

[0059] Step three, immerse the alkali-cooked bamboo fiber into the softener treatment solution for soaking treatment, in this step, the bath temperature is 55℃, the treatment time is 3h, and the bath ratio is 1:25;

[0060] Step four, soak the bamboo fiber prepared in step three with anhydrous ethanol, then wash it with tap water, and dry it naturally.

[0061] Example 2:

[0062] The preparation method used in this embodiment is consistent with that of Embodiment 1, the difference lies in that the raw material components used are different, the raw materials of this embodiment are respectively 82 parts of wood ash, 65 parts of special fiber, 420 parts of cement, 110 parts of mineral admixture, 120 parts of fine aggregate, 120 parts of coarse aggregate, 15 parts of water reducing agent, and 180 parts of water, wherein the fine aggregate is quartz sand, the mineral admixture is fly ash, and the cement is portland cement.

[0063] The test performance of the ultra-high performance concrete material prepared in this embodiment is shown in Table 2.

[0064] Embodiment 3:

[0065] The preparation method used in this embodiment is consistent with that of Embodiment 1, the difference lies in that the raw material components used are different, the raw materials of this embodiment are respectively 78 parts of wood ash, 60 parts of special fiber, 420 parts of cement, 110 parts of mineral admixture, 120 parts of fine aggregate, 120 parts of coarse aggregate, 15 parts of water reducing agent, and 180 parts of water, wherein the fine aggregate is quartz sand, the mineral admixture is fly ash, and the cement is portland cement.

[0066] The test performance of the ultra-high performance concrete material prepared in this embodiment is shown in Table 2.

[0067] Embodiment 4:

[0068] The preparation method used in this embodiment is consistent with that of Embodiment 1, the difference lies in that the raw material components used are different, the raw materials of this embodiment are respectively 75 parts of wood ash, 55 parts of special fiber, 420 parts of cement, 110 parts of mineral admixture, 120 parts of fine aggregate, 120 parts of coarse aggregate, 15 parts of water reducing agent, and 180 parts of water, wherein the fine aggregate is quartz sand, the mineral admixture is fly ash, and the cement is portland cement.

[0069] The test performance of the ultra-high performance concrete material prepared in this embodiment is shown in Table 2.

[0070] Embodiment 5:

[0071] The preparation method used in this embodiment is consistent with that of Embodiment 1, the difference lies in that the raw material components used are different, the raw materials of this embodiment are respectively 70 parts of wood ash, 45 parts of special fiber, 420 parts of cement, 110 parts of mineral admixture, 120 parts of fine aggregate, 120 parts of coarse aggregate, 15 parts of water reducing agent, and 180 parts of water, wherein the fine aggregate is quartz sand, the mineral admixture is fly ash, and the cement is portland cement.

[0072] The test performance of the super high performance concrete material prepared in this embodiment is shown in Table 2.

[0073] Embodiment 6

[0074] The preparation method adopted in this embodiment is consistent with that of Embodiment 1, except that the raw material components used are different. The raw materials in this embodiment are respectively 67 parts of wood ash, 35 parts of special fiber, 420 parts of cement, 110 parts of mineral admixture, 120 parts of fine aggregate, 120 parts of coarse aggregate, 15 parts of water reducing agent, and 180 parts of water. The fine aggregate is quartz sand, the mineral admixture is fly ash, and the cement is portland cement.

[0075] The test performance of the super high performance concrete material prepared in this embodiment is shown in Table 2.

[0076] Embodiment 7

[0077] The preparation method adopted in this embodiment is consistent with that of Embodiment 1, except that the raw material components used are different. The raw materials in this embodiment are respectively 63 parts of wood ash, 30 parts of special fiber, 420 parts of cement, 110 parts of mineral admixture, 120 parts of fine aggregate, 120 parts of coarse aggregate, 15 parts of water reducing agent, and 180 parts of water. The fine aggregate is quartz sand, the mineral admixture is fly ash, and the cement is portland cement.

[0078] The test performance of the super high performance concrete material prepared in this embodiment is shown in Table 2.

[0079] Embodiment 8

[0080] The preparation method adopted in this embodiment is consistent with that of Embodiment 1, except that the raw material components used are different. The raw materials in this embodiment are respectively 57 parts of wood ash, 25 parts of special fiber, 420 parts of cement, 110 parts of mineral admixture, 120 parts of fine aggregate, 120 parts of coarse aggregate, 15 parts of water reducing agent, and 180 parts of water. The fine aggregate is quartz sand, the mineral admixture is fly ash, and the cement is portland cement.

[0081] The test performance of the super high performance concrete material prepared in this embodiment is shown in Table 2.

[0082] Embodiment 9

[0083] The preparation method used in this embodiment is consistent with that of Embodiment 1, the difference lies in that the raw material components used are different, the raw materials of this embodiment are respectively as follows in parts by weight: wood ash 53 parts, special fiber 20 parts, cement 420 parts, mineral admixture 110 parts, fine aggregate 120 parts, coarse aggregate 120 parts, water reducing agent 15 parts, and water 180 parts, wherein the fine aggregate is quartz sand, the mineral admixture is fly ash, and the cement is portland cement.

[0084] The test performance of the ultra-high performance concrete material prepared in this embodiment is shown in Table 2.

[0085] Embodiment 10:

[0086] The preparation method used in this embodiment is consistent with that of Embodiment 1, the difference lies in that the raw material components used are different, the raw materials of this embodiment are respectively as follows in parts by weight: wood ash 53 parts, special fiber 20 parts, cement 420 parts, mineral admixture 110 parts, fine aggregate 120 parts, coarse aggregate 120 parts, water reducing agent 15 parts, and water 180 parts, wherein the fine aggregate is quartz sand, the mineral admixture is fly ash, and the cement is portland cement.

[0087] The test performance of the ultra-high performance concrete material prepared in this embodiment is shown in Table 2.

[0088] Comparative Example:

[0089] This comparative example provides an ultra-high performance concrete, and the preparation raw materials include the following component raw materials: portland cement 400 parts, quartz sand 110 parts, stone 100 parts, fly ash 140 parts, polycarboxylic acid water reducing agent 20 parts, composite steel fiber 40 parts, rice husk ash 25 parts, and water 230 parts.

[0090] The preparation method of the ultra-high performance concrete includes the following steps:

[0091] S1, according to the proportion, the stone, fly ash and composite steel fiber are uniformly mixed to obtain a premixed material;

[0092] S2, the premixed material is mixed with other components and stirred to obtain a mixed base;

[0093] S3, the stirred mixed base is poured into a mold, and then the concrete is vibrated to make the concrete dense;

[0094] S4, the shaped concrete is cured to ensure the strength and durability of the concrete, and the curing method adopts wet cloth covering, the relative humidity is 90%, and the curing time is 15 days.

[0095] The final performance of the ultra-high performance concrete product is shown in Table 2.

[0096] Further, the following provides the practical application parameter performance data of the ultra-high performance concrete prepared by the embodiments of the present application, and the detailed test data is shown in Tables 1-2.

[0097] Table 1: Concrete internal wood ash and special fiber addition parameter setting table.

[0098] Serial number 1 2 3 4 5 6 7 8 9 10 Wood ash 85 82 78 75 70 67 63 57 53 50 Specialty fibers 75 65 60 55 45 35 30 25 20 15

[0099] Table 2: High-performance concrete comprehensive performance data determination table

[0100]

[0101]

[0102] The following is an analysis of the performance gap of the ultra-high performance concrete prepared by the 10 embodiments and one comparative example:

[0103] I. In terms of compressive strength

[0104] 15-hour compressive strength: The 15-hour compressive strength of the embodiments is between 32.7 MPa and 39.2 MPa, while that of the comparative example is only 24.9 MPa. The embodiments are significantly higher than the comparative example, indicating that by adjusting the amount of wood ash and special fiber, the early compressive strength of the concrete can be significantly improved. With the change of the amount of wood ash and special fiber, the 15-hour compressive strength has certain fluctuations, but is overall stable and much higher than that of the comparative example.

[0105] 30-day compressive strength: The 30-day compressive strength of the embodiments is between 207.2 MPa and 228.2 MPa, and that of the comparative example is 157.8 MPa. The embodiments are also much higher than the comparative example, reflecting the advantage of the preparation method in long-term strength development. The strength difference between the embodiments is relatively small, indicating that adjusting the amount of raw materials within a certain range has a relatively gentle effect on long-term compressive strength.

[0106] II. In terms of slump

[0107] 0h slump: The 0h slump of the embodiments is between 162 mm and 192 mm, and that of the comparative example is 219 mm. The initial slump of the comparative example is significantly higher than that of the embodiments, which may be due to the difference in composition or mix proportion of the raw materials in the comparative example, resulting in better fluidity. However, the slump of the embodiments can also meet certain construction requirements, and with the change of the amount of wood ash and special fiber, the slump has certain change trend.

[0108] 15h slump: the 15h slump of the examples was between 89 mm and 109 mm, and the slump of the comparative example was 142 mm. The slump of the examples and the comparative example decreased over time, but the slump of the examples decreased relatively less, indicating that the concrete prepared in the examples had an advantage in maintaining fluidity.

[0109] III. Flexural strength

[0110] The one-week flexural strength of the examples was between 25.71 MPa and 28.61 MPa, and the flexural strength of the comparative example was 19.92 MPa. The flexural strength of the examples was significantly higher than that of the comparative example, indicating that the addition of wood ash and special fibers had a significant effect on improving the flexural performance of the concrete. There were also differences in the flexural strength between the examples, which may be related to changes in the amount of raw materials and the microstructure of the concrete.

[0111] In summary, through the comparison of the 10 examples and the comparative example, it can be seen that the ultra-high performance concrete prepared by the preparation method has obvious advantages in terms of compressive strength, flexural strength, etc. Although the slump is slightly lower than that of the comparative example, it still meets certain construction requirements. At the same time, by adjusting the amount of wood ash and special fibers, the performance of the concrete can be regulated to a certain extent to meet the needs of different projects.

[0112] Although embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing ultra-high performance concrete material using special fibers, characterized in that: The method comprises the following steps: S1. Raw material preparation: prepare wood ash, specialty fiber, cement, mineral admixtures, fine aggregate, coarse aggregate, water reducer and water; S2. Raw material pretreatment: Grinding the wood ash for fineness treatment, wherein the fineness of the ground wood ash is 700-800 mesh, and the length of the special fiber is controlled to be 2-2.5 cm and the diameter is 0.1-0.5 mm; S3. Mixing and stirring: Add cement, mineral admixtures, fine aggregate, and coarse aggregate into a mixer. After dry mixing for a certain period of time, add treated wood ash and specialty fiber, continue to stir evenly, and then add water and water reducing agent and continue to stir; S4, molding and curing: pouring the mixed concrete into a mold for molding. After the molded concrete is cured, the finished ultra-high performance concrete material is obtained; The raw materials are respectively as follows by weight: 50-85 parts of wood ash, 15-75 parts of special fiber, 420-480 parts of cement, 110-145 parts of mineral admixture, 120-150 parts of fine aggregate, 100-150 parts of coarse aggregate, 15-30 parts of water reducer and 170-280 parts of water.

2. The method for preparing ultra-high performance concrete material using special fibers according to claim 1, characterized in that: The method for producing the special fiber comprises the following steps: Step 1: Saw and split the original bamboo into pieces with a length of 10-40 mm, then boil the original bamboo pieces in boiling water for 2-3 hours; Step 2: Take out the scoured bamboo pieces, crush them into bamboo strips, and then soak the bamboo strips in a sodium hydroxide solution; Step 3: soaking the alkali-boiled bamboo fiber in a softener treatment solution; Step 4: Soak the bamboo fiber obtained in step 3 in anhydrous ethanol, then wash it with tap water and dry it naturally.

3. The method for preparing ultra-high performance concrete material using special fibers according to claim 2, characterized in that: In the step 2, the bath temperature is 100-110° C., the immersion time is 3-4 hours, and the bath ratio is 1:(25-30).

4. The method for preparing ultra-high performance concrete material using special fibers according to claim 2, characterized in that: In the step 3, the bath temperature is 45-55° C., the treatment time is 2-3 h, and the bath ratio is 1:(25-30).

5. The method for preparing ultra-high performance concrete material using special fibers according to claim 1, characterized in that: In the step S4, the formed concrete is cured for 15 to 20 days at a temperature of 25° C. and a relative humidity of 90%.

6. The method for preparing ultra-high performance concrete material using special fibers according to claim 1, characterized in that: The fine aggregate is quartz sand, river sand or machine-made sand, and the fineness modulus is between 2.4 and 2.

8.

7. The method for preparing ultra-high performance concrete material using special fibers according to claim 1, characterized in that: The mineral admixture includes one or more of silica fume, fly ash and slag powder.

8. The method for preparing ultra-high performance concrete material using special fibers according to claim 1, characterized in that: The cement is one of Portland cement, high-belite cement and sulphoaluminate cement.

Images