Composite fiber doped recycled aggregate concrete and method for preparing the same

Abstract

The application discloses a kind of composite fiber doped recycled aggregate concrete and preparation method thereof, belong to building material technical field. Including the following mass parts of raw materials: cement 40-60 parts, recycled aggregate 20-30 parts, composite fiber 1-6 parts, fly ash 22-30 parts, water reducing agent 1-5 parts and water 10-15 parts. Among them, the composite fiber is mixed by glass fiber, polypropylene fiber and basalt fiber;The mass ratio of glass fiber, polypropylene fiber and basalt fiber is 1:(0.2-0.6):1. The application forms a kind of building material with good durability and compressive strength performance by mixing cement, recycled aggregate, composite fiber, fly ash and water reducing agent and the like raw materials according to certain proportion. It has good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and in particular relates to a composite fiber-doped recycled aggregate concrete and its preparation method. Background Technology

[0002] Concrete is a widely used basic material in construction engineering, but traditional concrete is mainly composed of cement, sand, and gravel, and the mining and processing of these materials cause significant environmental pollution. Therefore, people have been seeking more environmentally friendly and sustainable building materials.

[0003] Composite fiber-reinforced recycled aggregate concrete is a mixture of cement, recycled aggregate, fiber, and water, offering improved durability and compressive strength while also being environmentally friendly. However, the production of recycled aggregates requires significant energy and chemical inputs, limiting its application.

[0004] Therefore, it is necessary to provide a novel composite fiber-doped recycled aggregate concrete that can effectively reduce its production cost. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a composite fiber-doped recycled aggregate concrete and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] One of the objectives of this invention is to provide a composite fiber-doped recycled aggregate concrete, comprising the following raw materials in parts by weight: 40-60 parts cement, 20-30 parts recycled aggregate, 1-6 parts composite fiber, 22-30 parts fly ash, 1-5 parts water-reducing agent, and 10-15 parts water.

[0008] This invention creates a building material with excellent performance by mixing cement, recycled aggregate, composite fiber, fly ash, and water-reducing agent in a specific ratio. Cement, as the main binder, improves the strength and hardness of the concrete; recycled aggregate enhances the compressive strength and durability of the concrete; composite fiber provides good reinforcement, increasing the tensile strength of the concrete; and fly ash improves the workability of the concrete and reduces its cost.

[0009] Furthermore, the composite fiber-doped recycled aggregate concrete comprises the following raw materials in parts by weight: 42-55 parts cement, 20-28 parts recycled aggregate, 2-4 parts composite fiber, 25-30 parts fly ash, 1-3 parts water-reducing agent, and 11-15 parts water.

[0010] This invention further improves the raw material ratio of the concrete, thereby optimizing its performance. Specifically, the cement content is slightly increased, enhancing the compressive strength of the concrete; while the proportions of fly ash and water-reducing agent are reduced, achieving a balance between the strength and durability of the concrete.

[0011] Furthermore, the specific processing steps for the recycled aggregate include: crushing waste concrete or bricks to a particle size of less than 4.75mm, washing with clean water to remove impurities, and pre-wetting until saturated and surface-dry. This processing method can effectively remove impurities from the aggregate and improve the strength and durability of the concrete.

[0012] Furthermore, the composite fiber is composed of a mixture of glass fiber, polypropylene fiber, and basalt fiber. This mixing method results in a good bond between the fibers, improving the tensile strength of the concrete.

[0013] Furthermore, the mass ratio of glass fiber, polypropylene fiber, and basalt fiber is 1:(0.2-0.6):1. This specific ratio allows the three fibers to exert their maximum reinforcing effect in concrete.

[0014] Furthermore, the fly ash is grade II or higher, which ensures the long-term performance of the concrete during use.

[0015] Furthermore, the water-reducing agent is a polycarboxylate water-reducing agent, which ensures the rapid setting and hardening characteristics of the concrete.

[0016] The second objective of this invention is to provide a method for preparing composite fiber-doped recycled aggregate concrete, comprising the following steps:

[0017] Weigh the raw materials by weight, add recycled aggregate and fly ash to the composite fiber, stir, and obtain a dry mixture;

[0018] Cement, water-reducing agent and water are added to the dry mixture for wet mixing and shearing, followed by curing, to obtain composite fiber-doped recycled aggregate concrete.

[0019] Furthermore, the parameters for the wet mixed shearing are: temperature 40-60℃, and shearing rate 110-180rpm.

[0020] The third objective of this invention is to provide an application of composite fiber-doped recycled aggregate concrete in the field of building materials.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] This invention discloses a composite fiber-doped recycled aggregate concrete and its preparation method. The concrete is composed of cement, recycled aggregate, composite fibers, fly ash, and a water-reducing agent, exhibiting good durability and compressive strength. By controlling the proportions of the raw materials, especially the specific ratio of fibers, the strength of the concrete can be effectively improved. The preparation method of this invention includes adjusting the mass of each raw material, adding recycled aggregate and fly ash, finally adding water for wet mixing and shearing, and curing under certain conditions. Furthermore, this invention also conducted application experiments on the composite fiber-doped recycled aggregate concrete in the field of building materials. The results show that the concrete of this invention has superior performance compared to existing technologies and has excellent application prospects. Detailed Implementation

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0025] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0026] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0027] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0028] This invention provides a composite fiber-doped recycled aggregate concrete, comprising the following raw materials in parts by weight: 40-60 parts cement, 20-30 parts recycled aggregate, 1-6 parts composite fiber, 22-30 parts fly ash, 1-5 parts water-reducing agent, and 10-15 parts water. Preferably, the composite fiber-doped recycled aggregate concrete comprises the following raw materials in parts by weight: 42-55 parts cement, 20-28 parts recycled aggregate, 2-4 parts composite fiber, 25-30 parts fly ash, 1-3 parts water-reducing agent, and 11-15 parts water.

[0029] As a typical but not limiting example, in the following preferred embodiments of the invention:

[0030] The composite fiber-doped recycled aggregate concrete contains 42 parts, 50 parts, 55 parts or any range or subrange of cement between the aforementioned proportions;

[0031] The composite fiber-doped recycled aggregate concrete contains 20 parts, 25 parts, 28 parts or any range or subrange of recycled aggregate between the aforementioned proportions;

[0032] The composite fiber-doped recycled aggregate concrete contains 2 parts, 3 parts, 4 parts or any range or subrange of composite fibers between the aforementioned proportions;

[0033] The composite fiber-doped recycled aggregate concrete contains 25 parts, 28 parts, 30 parts or any range or subrange of fly ash between the aforementioned proportions.

[0034] The composite fiber-doped recycled aggregate concrete contains 1 part, 2 parts, 3 parts or any range or subrange of water-reducing agent between the aforementioned proportions;

[0035] The composite fiber-doped recycled aggregate concrete contains 11, 13, 15 parts of water or any range or subrange of the aforementioned proportions.

[0036] In the following preferred embodiments of the present invention, the specific processing steps of the recycled aggregate include: crushing waste concrete or bricks to a particle size of less than 4.75 mm, washing with clean water to remove impurities, and pre-wetting until saturated and surface-dry.

[0037] In some preferred embodiments of the present invention, the composite fiber is composed of a mixture of glass fiber, polypropylene fiber, and basalt fiber in a mass ratio of 1:(0.2-0.6):1. Exemplarily, in the following embodiments of the present invention, the mass ratio of the glass fiber, polypropylene fiber, and basalt fiber can be selected as 1:0.2:1, 1:0.4:1, 1:0.6:1, or any range between the aforementioned ratios.

[0038] The glass fibers have a diameter of 25 μm and a length of 8-10 mm; the polypropylene fibers have a diameter of 20 μm and are composed of two sizes with lengths of 5-8 mm and 10-15 mm, with a mass ratio of 1:1; the basalt fibers have a diameter of 15 μm and a length of 2-5 mm. This embodiment of the invention selects fibers of specific sizes for blending, which can fully utilize the characteristics and advantages of various fibers, thereby achieving a balanced state in the composite fiber. This ensures both the strength and stiffness of the concrete, while also enhancing its toughness and durability. Therefore, this fiber selection method has a positive impact on concrete performance, greatly improving the concrete's usability.

[0039] In the following preferred embodiments of the present invention, the fly ash is grade II or higher fly ash.

[0040] In the following preferred embodiments of the present invention, the water-reducing agent is a polycarboxylate water-reducing agent.

[0041] This invention also provides a method for preparing composite fiber-doped recycled aggregate concrete, comprising the following steps: weighing raw materials by mass, adding recycled aggregate and fly ash to composite fibers, stirring to obtain a dry mixture; adding cement, water-reducing agent and water to the dry mixture for wet mixing and shearing, curing, to obtain composite fiber-doped recycled aggregate concrete.

[0042] In some preferred embodiments of the present invention, the parameters of the wet mixing shearing are: temperature 40-60℃, shearing rate 110-180 rpm, and time 3-6 h. As a typical but non-limiting example, in the following embodiments of the present invention, the temperature of the wet mixing shearing can be selected as 40℃, 50℃, or 60℃; the shearing rate of the wet mixing shearing can be selected as 110 rpm, 150 rpm, or 180 rpm; and the time of the wet mixing shearing is 3 h, 5 h, or 6 h.

[0043] This invention also provides an application of composite fiber-doped recycled aggregate concrete in the field of building materials.

[0044] In some alternative embodiments, a composite microbial agent may be added to the composite fiber-doped recycled aggregate concrete to obtain a new formula, namely: a composite fiber-doped recycled aggregate concrete comprising the following raw materials in parts by weight: 40-60 parts cement, 20-30 parts recycled aggregate, 1-6 parts composite fiber, 22-30 parts fly ash, 1-5 parts water-reducing agent, 10-15 parts water and 0.5-1.5 parts composite microbial agent.

[0045] In some preferred embodiments of the present invention, the composite microbial agent is prepared by mixing *Sporosarcina pasteurii* and *Bacillus siamensis* in a mass ratio of 1:(1.5-3). As a typical but non-limiting example, in the following embodiments of the present invention, the mass ratio of *Sporosarcina pasteurii* to *Bacillus siamensis* may be selected as 1:2. *Sporosarcina pasteurii* (Beijing Bio-Tech Co., Ltd.) can repair concrete cracks through microbially induced calcium carbonate precipitation (MICP). Its metabolite, calcium carbonate, can fill cracks and micropores, thereby improving the density and strength of concrete. *Bacillus siamensis* (Shanghai Yushao Biotechnology Co., Ltd.) has good thermal and acid-base stability, and can adapt to the repair of concrete cracks under different environmental conditions. Its metabolites can promote the mineralization reaction inside concrete, enhancing the durability of concrete. Through the synergistic effect of multiple strains, defects in recycled concrete aggregates can be repaired more effectively, thereby significantly improving its compressive strength, flexural strength, and durability. Most importantly, this invention adds a composite microbial agent to the composite fiber. The composite microbial agent can act on the fiber surface and improve its performance in concrete by changing the chemical properties of the fiber surface. The two have a synergistic effect.

[0046] The preparation method of composite fiber-doped recycled aggregate concrete with added composite microbial agent includes the following steps: weigh the raw materials by mass, add recycled aggregate and fly ash to the composite fiber, stir to obtain a dry mixture; add cement, water-reducing agent and water to the dry mixture, and finally add the composite microbial agent, wet mix and shear, and cure to obtain composite fiber-doped recycled aggregate concrete.

[0047] Unless otherwise specified, "room temperature" in this invention refers to 20-30℃.

[0048] Unless otherwise specified, the term "parts" in this invention refers to parts by weight.

[0049] All raw materials used in this invention were purchased from the market.

[0050] The technical solution of the present invention will be further illustrated by the following embodiments.

[0051] In the following examples, the cement is P.O42.5R ordinary Portland cement (Wuhan Meishan Qiaoye Cement Co., Ltd.); the water-reducing agent (Wuhan Huaxuan High-Tech Co., Ltd.) is a polycarboxylate water-reducing agent with a solid content of 18% and a water reduction rate of 32%; the recycled aggregate is (Wuhan Tianyicheng Renewable Resources Co., Ltd.); the fly ash (Handan Fuxing District Yingqi Fly Ash Sales Co., Ltd.) is Grade II fly ash; the glass fiber (Hubei Ping'an Electrical Materials Co., Ltd.) has a diameter of 25μm and a length of 8-10mm; the polypropylene fiber (Jiangsu Subote New Materials Co., Ltd.) has a diameter of 20μm and is composed of two sizes with lengths of 5-8mm and 10-15mm, with a mass ratio of 1:1; and the basalt fiber (Zhongding Economic Development Co., Ltd.) has a diameter of 15μm and a length of 2-5mm.

[0052] Example 1

[0053] A composite fiber-doped recycled aggregate concrete comprises the following raw materials in parts by weight: 50 parts cement, 25 parts recycled aggregate, 3 parts composite fiber (the mass ratio of glass fiber, polypropylene fiber and basalt fiber is 1:0.4:1), 28 parts fly ash, 2 parts water-reducing agent and 13 parts water.

[0054] A method for preparing composite fiber-doped recycled aggregate concrete includes the following steps:

[0055] (1) Crush waste concrete or bricks to a particle size of less than 4.75 mm, wash with clean water to remove impurities, pre-wet until saturated surface dry state, and obtain recycled aggregate;

[0056] (2) Weigh the raw materials according to the above mass, add recycled aggregate and fly ash to the composite fiber, stir, and obtain a dry mixture;

[0057] (3) Add cement, water-reducing agent and water to the dry mixture, and then wet mix and shear at 50℃ and 150rpm for 5h, and cure to obtain composite fiber-doped recycled aggregate concrete.

[0058] Example 2

[0059] A composite fiber-doped recycled aggregate concrete comprises the following raw materials in parts by weight: 42 parts cement, 28 parts recycled aggregate, 2 parts composite fiber (the mass ratio of glass fiber, polypropylene fiber and basalt fiber is 1:0.6:1), 30 parts fly ash, 3 parts water-reducing agent and 11 parts water.

[0060] A method for preparing composite fiber-doped recycled aggregate concrete includes the following steps:

[0061] (1) Crush waste concrete or bricks to a particle size of less than 4.75 mm, wash with clean water to remove impurities, pre-wet until saturated surface dry state, and obtain recycled aggregate;

[0062] (2) Weigh the raw materials according to the above mass, add recycled aggregate and fly ash to the composite fiber, stir, and obtain a dry mixture;

[0063] (3) Add cement, water-reducing agent and water to the dry mixture, and then wet mix and shear at 110 rpm at 60℃ for 3 hours, and cure to obtain composite fiber-doped recycled aggregate concrete.

[0064] Example 3

[0065] A composite fiber-doped recycled aggregate concrete comprises the following raw materials in parts by weight: 55 parts cement, 20 parts recycled aggregate, 4 parts composite fiber (the mass ratio of glass fiber, polypropylene fiber and basalt fiber is 1:0.2:1), 25 parts fly ash, 1 part water-reducing agent and 15 parts water.

[0066] A method for preparing composite fiber-doped recycled aggregate concrete includes the following steps:

[0067] (1) Crush waste concrete or bricks to a particle size of less than 4.75 mm, wash with clean water to remove impurities, pre-wet until saturated surface dry state, and obtain recycled aggregate;

[0068] (2) Weigh the raw materials according to the above mass, add recycled aggregate and fly ash to the composite fiber, stir, and obtain a dry mixture;

[0069] (3) Add cement, water-reducing agent and water to the dry mixture, and then wet mix and shear at 80 rpm at 40℃ for 6 hours, and cure to obtain composite fiber-doped recycled aggregate concrete.

[0070] Comparative Example 1

[0071] Same as Example 1, except that the mass ratio of glass fiber, polypropylene fiber and basalt fiber is 1:1:0.4.

[0072] Comparative Example 2

[0073] Same as Example 1, except that the amount of composite fiber added remains the same, and the composite fiber is a mixture of glass fiber, polypropylene fiber, basalt fiber and steel fiber in a mass ratio of 1:0.4:1:1.

[0074] Comparative Example 3

[0075] Same as Example 1, except that the mass of glass fiber is replaced with steel fiber, that is, the mass ratio of steel fiber, polypropylene fiber and basalt fiber is 1:0.4:1.

[0076] Comparative Example 4

[0077] Same as Example 1, except that the diameter of the glass fiber, polypropylene fiber and basalt fiber is 20 μm and the length is 5-8 mm.

[0078] The composite fiber-doped recycled aggregate concretes prepared in Examples 1-3 and Comparative Examples 1-4 were tested according to the testing standards, and the results are shown in Table 1.

[0079] The mechanical properties of the concrete prepared in each example and comparative example were determined according to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the frost resistance of the concrete specimens was tested according to "Test Procedures for Hydraulic Concrete" (DL / T5150-2001). The test specimens were prisms with a length × width × height of 150mm × 150mm × 400mm, and were subjected to 300 consecutive freeze-thaw cycles. The durability index was calculated using the following formula: Durability Index = p n × number of freeze-thaw cycles / 300, where p n p represents the relative dynamic elastic modulus of the specimen. n =f 2 n / f 2 1×100, f n The natural frequency of the specimen after freeze-thaw cycles, in Hz, f 2 1 represents the natural frequency of the specimen before freeze-thaw cycles, in Hz.

[0080] Table 1

[0081] 28-day compressive strength / MPa 28-day flexural strength / MPa Splitting tensile strength / MPa Durability Index Example 1 94.3 31.6 9.27 169 Example 2 93.8 29.7 9.04 166 Example 3 94.1 30.8 9.16 168 Comparative Example 1 86.2 23.7 8.34 143 Comparative Example 2 91.5 28.4 8.89 158 Comparative Example 3 80.1 19.6 7.04 142 Comparative Example 4 82.4 20.7 7.16 144

[0082] As shown in Table 1, the composite fiber-doped recycled aggregate concrete prepared using the methods of Examples 1-3 of this invention exhibits strong durability, is not prone to cracking, and has high compressive and flexural strengths. Compared to Comparative Example 1, Example 1 only changed the ratio of glass fiber, polypropylene fiber, and basalt fiber, yet the concrete performance was significantly reduced. Compared to Comparative Example 2, Example 1 showed that even with the addition of a steel fiber, the concrete performance was not significantly improved. Compared to Comparative Example 3, Example 1 only replaced one type of fiber in the composite, resulting in a significant decrease in concrete performance. These results indicate that the concrete formulation provided by this invention requires a specific ratio of fibers, and more types are not necessarily better; a specific blending relationship is required. Excessive fiber blending only increases production costs, and at this ratio, only specific fiber types improve concrete performance. Compared to Comparative Example 4, Example 1 only changed the fiber particle size distribution, yet the concrete performance decreased, indicating that this invention is not simply a combination of different fibers but also needs to consider the influence of fiber diameter and length on performance.

[0083] Overall, Example 1 has the best performance, and therefore Example 1 will be used as the basis for further improvements.

[0084] Example 4

[0085] A composite fiber-doped recycled aggregate concrete comprises the following raw materials in parts by weight: 50 parts cement, 25 parts recycled aggregate, 3 parts composite fiber (the mass ratio of glass fiber, polypropylene fiber and basalt fiber is 1:0.4:1), 28 parts fly ash, 2 parts water-reducing agent, 13 parts water, and 1 part composite microbial agent (the mass ratio of Bacillus pasteurellii and Bacillus sicca is 1:2).

[0086] A method for preparing composite fiber-doped recycled aggregate concrete includes the following steps:

[0087] (1) Weigh the raw materials according to the above mass, add recycled aggregate and fly ash to the composite fiber, stir, and obtain a dry mixture;

[0088] (2) Add cement, water-reducing agent and water to the dry mixture, then add composite microbial agent, and finally wet mix and shear at 50℃ and 150rpm for 5h, and cure to obtain composite fiber-doped recycled aggregate concrete.

[0089] Comparative Example 5

[0090] Same as Example 4, except that Bacillus sicca is replaced with alkali-resistant Bacillus, that is, the compound bacterial agent is made by mixing Bacillus pasteurellii and alkali-resistant Bacillus in a mass ratio of 1:2.

[0091] Comparative Example 6

[0092] Same as Example 4, except that the mass ratio of Bacillus pasteurellii to Bacillus sicca is 2:1.

[0093] Comparative Example 7

[0094] Same as Example 4, except that the same mass of composite fiber is replaced with cement, that is, no composite fiber is added.

[0095] The composite fiber-doped recycled aggregate concrete prepared in Example 4 and Comparative Examples 5-7 were tested according to the testing standards. The results are shown in Table 2. The testing method was the same as in Example 1.

[0096] Table 2

[0097] 28-day compressive strength / MPa 28-day flexural strength / MPa Splitting tensile strength / MPa Durability Index Example 1 94.3 31.6 9.27 169 Example 4 98.4 34.7 11.03 175 Comparative Example 5 95.2 31.9 9.41 171 Comparative Example 6 95.6 32.2 9.47 171 Comparative Example 7 78.9 18.7 6.68 136

[0098] As can be seen from Table 2, the concrete prepared using the method of Example 4 of this invention exhibits significantly improved performance compared to Example 1. However, Comparative Examples 5 and 6 show only minor improvements compared to Example 1 due to differences in the types and proportions of microbial compounds used. In Comparative Example 7, the absence of composite fibers resulted in a decrease in concrete performance even with the addition of composite microbial agents, further demonstrating the interaction between the fibers and microbial agents specified in this invention.

[0099] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A composite fiber-doped recycled aggregate concrete, characterized in that, The raw materials include the following parts by weight: 40-60 parts cement, 20-30 parts recycled aggregate, 1-6 parts composite fiber, 22-30 parts fly ash, 1-5 parts water-reducing agent and 10-15 parts water; The composite fiber is composed of glass fiber, polypropylene fiber and basalt fiber; the mass ratio of glass fiber, polypropylene fiber and basalt fiber is 1:(0.2-0.6):

1. The glass fiber has a diameter of 25μm and a length of 8-10mm; The polypropylene fiber has a diameter of 20μm and is composed of two sizes with lengths of 5-8mm and 10-15mm, with a mass ratio of 1:

1. The basalt fibers have a diameter of 15 μm and a length of 2-5 mm.

2. The composite fiber-doped recycled aggregate concrete according to claim 1, characterized in that, The raw materials include the following parts by weight: 42-55 parts cement, 20-28 parts recycled aggregate, 2-4 parts composite fiber, 25-30 parts fly ash, 1-3 parts water-reducing agent, and 11-15 parts water.

3. The composite fiber-doped recycled aggregate concrete according to claim 1 or 2, characterized in that, The specific processing steps for the recycled aggregate include: crushing waste concrete or bricks to a particle size of less than 4.75mm, washing with clean water to remove impurities, and pre-wetting until saturated and surface-dry.

4. The composite fiber-doped recycled aggregate concrete according to claim 1 or 2, characterized in that, The fly ash is grade II or higher.

5. The composite fiber-doped recycled aggregate concrete according to claim 1 or 2, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent.

6. A method for preparing composite fiber-doped recycled aggregate concrete as described in any one of claims 1-5, characterized in that, Includes the following steps: Weigh the raw materials by weight, add recycled aggregate and fly ash to the composite fiber, stir, and obtain a dry mixture; Cement, water-reducing agent and water are added to the dry mixture for wet mixing and shearing, followed by curing, to obtain composite fiber-doped recycled aggregate concrete.

7. The preparation method according to claim 6, characterized in that, The parameters for the wet mixed shearing are: temperature 40-60℃, shearing rate 110-180rpm.

8. The application of composite fiber-doped recycled aggregate concrete as described in any one of claims 1-5 in the field of building materials.