CN114315242A - Recycled steel fiber concrete and preparation method thereof - Google Patents

Abstract

The application relates to the technical field of concrete, and particularly discloses recycled steel fiber concrete and a preparation method thereof. The recycled steel fiber concrete is prepared from the following raw materials in parts by weight: 350 parts of cement, 60-100 parts of microbead fly ash particles, 10-30 parts of modified steel fibers, 4-12 parts of ramie fibers, 900 parts of regenerated coarse aggregate, 600 parts of regenerated fine aggregate, 2-10 parts of a polycarboxylic acid water reducing agent and 220 parts of water 150; the preparation method comprises the following steps: uniformly mixing the recycled coarse aggregate and the recycled fine aggregate to obtain a mixture A; and (3) uniformly mixing cement and water, adding the micro-bead fly ash particles, the modified steel fibers and the ramie fibers, uniformly mixing, and finally adding a polycarboxylic acid water reducing agent to prepare the regenerated steel fiber concrete. The application of the recycled steel fiber concrete has the advantage of higher strength through the synergistic effect between the raw materials.

Description

Recycled steel fiber concrete and preparation method thereof

Technical Field

The application relates to the technical field of concrete, in particular to recycled steel fiber concrete and a preparation method thereof.

Background

The steel fiber concrete is a novel multiphase composite material formed by doping short steel fibers which are distributed disorderly into common concrete. The regenerated steel fiber concrete is prepared by crushing, cleaning and grading waste concrete blocks, mixing the crushed, cleaned and graded concrete blocks with a certain proportion, partially or completely replacing natural aggregates such as sand stones and the like, and then adding cement, water, steel fibers and the like.

At present, the recycled steel fiber reinforced concrete has wide application, and is mainly applied to the fields of house engineering, hydraulic engineering, road and bridge engineering, ports, ocean engineering and the like. However, a large amount of steel fibers are mixed in the concrete and distributed in a disordered manner in the concrete to form a net structure, so that more gaps are formed in the concrete, the interior is loose, and the strength of the concrete is influenced.

Disclosure of Invention

In order to enhance the strength of concrete, the application provides a recycled steel fiber concrete and a preparation method thereof.

In a first aspect, the present application provides a recycled steel fiber concrete, which adopts the following technical scheme:

the recycled steel fiber concrete is prepared from the following raw materials in parts by weight: 350 parts of cement, 60-100 parts of microbead fly ash particles, 10-30 parts of modified steel fibers, 4-12 parts of ramie fibers, 900 parts of regenerated coarse aggregate, 600 parts of regenerated fine aggregate, 2-10 parts of a polycarboxylic acid water reducing agent and 220 parts of water 150;

the modified steel fiber is prepared by modifying the steel fiber by adopting ferric phosphate and a silane coupling agent.

Further, S1: putting 9-11kg of steel fiber into 40-60L of water, performing ultrasonic treatment for 8-12min under the power of 350-;

s2: mixing 80-100L of water and 8-12L of ethanol, stirring for 20-30min to obtain a mixture, putting the first steel fiber into the mixture, adjusting the pH to 4.5-5.0 by using 98% by mass of glacial acetic acid, performing ultrasonic treatment for 8-12min under the power of 1000-1200w, adding 4-8L of gamma (2, 3-epoxypropoxy) propyl trimethoxy silane, stirring for 15-25min at the temperature of 40-60 ℃, standing for 10-14h, cooling to 22 +/-4 ℃, performing suction filtration, washing the solid with water for 3-5 times, and drying for 3-5h at the temperature of 35-45 ℃ to obtain a second steel fiber;

s3: and (3) placing the second steel fiber in 25-40L of 85% iron phosphate solution by mass, stirring for 5-10min, soaking at 80-90 ℃ for 15-25min, taking out the second steel fiber, washing with water for 3-5 times, and drying at 35-45 ℃ for 2-4h to obtain the modified steel fiber.

By adopting the technical scheme, the recycled steel fiber concrete has good compressive strength and flexural strength through the synergistic effect of the raw materials, wherein the compressive strength of 7d is 25.3-35.6MPa, the compressive strength of 28d is 44.5-56.9MPa, the flexural strength of 7d is 6.8-11.6MPa, and the flexural strength of 28d is 11.5-16.2 MPa.

The cement, the polycarboxylic acid water reducing agent and the water are the basic raw materials of the concrete. The micro-bead fly ash particles can be embedded into gaps of cement, so that the gaps of the cement are reduced, the compactness is improved, the micro-bead fly ash particles have high strength, when cracks appear in the concrete, the crack extension and expansion can be reduced, the cracks are deflected, the fracture energy of main cracks is weakened, and the compressive strength of the concrete is improved. The steel fiber has smooth surface and poor bonding capability with cement, and influences the distribution of the steel fiber in the concrete, thereby influencing the strength of the concrete. Firstly, the steel fiber is treated by using a silane coupling agent, and the silane coupling agent can improve the corrosion resistance of the steel fiber, prolong the service life of the steel fiber and reduce the influence on concrete; and the silane coupling agent can also enhance the bonding capability of the steel fiber and the cement. And the iron phosphate is used for treating the steel fiber, so that a large number of short rod-shaped iron phosphating films are distributed on the surface of the steel fiber, the surface of the steel fiber is roughened, more gullies are generated, hydroxyapatite and brushite can be generated on the surface of the steel fiber, and a positive effect is exerted on the binding force of the steel fiber and cement. The adhesive force of the steel fiber and the cement can be increased through the synergistic effect of the silane coupling agent and the iron phosphate, so that the strength and the crack resistance of the concrete are improved.

The ramie fibers are natural fibers, have small diameters, and can effectively fill gaps of the steel fibers, so that a good space structure is formed with the steel fibers, the compactness inside concrete is improved, and the flexural strength of the concrete is enhanced. Moreover, the ramie fibers are corrosion resistant, have larger surface energy and can stably exist in concrete. The recycled coarse aggregate and the recycled fine aggregate are renewable aggregates, so that the recycled aggregate not only can replace part of cement, reduce the production cost and enhance the compressive strength, but also realizes waste utilization, saves resources and protects the environment.

Preferably, the method comprises the following steps: the recycled steel fiber concrete comprises the following raw materials in parts by weight: 320 parts of cement, 280-85 parts of microbead fly ash particles, 15-21 parts of modified steel fibers, 7-10.5 parts of ramie fibers, 950-1120 parts of regenerated coarse aggregate, 680-1050 parts of regenerated fine aggregate, 5-8 parts of a polycarboxylic acid water reducing agent and 180-200 parts of water.

By adopting the technical scheme, the weight proportion of cement, the micro-bead fly ash particles, the modified steel fibers, the ramie fibers, the recycled coarse aggregate, the recycled fine aggregate, the polycarboxylic acid water reducing agent and water is optimized, so that the compressive strength, the breaking strength and the cracking resistance of concrete are enhanced.

Preferably, the method comprises the following steps: the addition amount of the modified steel fiber is 6-8wt% of the cement.

The addition amount of the modified steel fiber is too small, so that the modified steel fiber cannot play a better role in improving the strength of concrete; the addition amount of the modified steel fiber is too much, so that the gap in the concrete is larger, the compactness in the concrete is influenced, and the compressive strength of the concrete is influenced. By adopting the technical scheme, when the addition amount of the steel fiber is in the range, the concrete can have better compressive strength.

Preferably, the method comprises the following steps: the weight ratio of the ramie fibers to the steel fibers is 1: (2-4).

The ramie fibers are too small in addition amount, cannot be well dispersed in concrete, and cannot well enhance the flexural strength of the concrete; the ramie fibers are added in too large amount, so that agglomeration is easily caused, and the dispersibility of the ramie fibers in the concrete is influenced, so that the strength of the concrete is influenced. By adopting the technical scheme, when the weight ratio of the steel fibers to the ramie fibers is in the range, the concrete has better flexural strength.

Preferably, the method comprises the following steps: the steel fiber is a corrugated steel fiber.

By adopting the technical scheme, the wavy steel fibers are wavy, and when the wavy steel fibers are applied to the raw materials of concrete, the contact area between the steel fibers and the concrete can be enhanced, the cohesiveness of the steel fibers and the concrete is increased, and the strength of the concrete is further enhanced.

Preferably, the method comprises the following steps: the ramie fiber is pretreated by triethylhexylphosphoric acid before use.

Further, 8-12kg of ramie fibers are soaked in 20-30kg of triethylhexylphosphoric acid for 1.5-2h, then the ramie fibers are taken out and dried at the temperature of 50-60 ℃ for 1-2h, and the pretreated ramie fibers are obtained.

By adopting the technical scheme, the triethyl hexyl phosphoric acid is used as the dispersing agent to modify the ramie fibers, so that the agglomeration phenomenon of the ramie fibers can be reduced, the dispersibility of the ramie fibers in concrete is improved, the ramie fibers are distributed in the concrete more uniformly, and the improvement of the breaking strength of the concrete is facilitated.

Preferably, the method comprises the following steps: the recycled coarse aggregate comprises waste rubber particles and waste concrete particles, and the weight ratio of the waste rubber particles to the waste concrete particles is 1: (2-3).

Through adopting above-mentioned technical scheme, abandonment rubber granule itself has toughness, can improve the flexural strength of concrete, can also fill between abandonment concrete granule, strengthens closely knit degree to improve the intensity of concrete. The waste rubber particles and the waste concrete particles are utilized, so that the waste is recycled, the cost is reduced, and the environment is protected.

Preferably, the method comprises the following steps: the recycled coarse aggregate is pretreated by triethanolamine and triisopropanolamine before use.

Further, 2-4kg of triethanolamine and 5-7kg of triisopropanolamine are mixed, stirred for 20-40min at the temperature of 40-50 ℃ to obtain a mixture, 4-6kg of regenerated coarse aggregate is put into the mixture, stirred for 30-50min, the solid is taken out, the solid is washed for 3-5 times by water and dried for 2.5-4h at the temperature of 80-100 ℃ to obtain the pretreated regenerated coarse aggregate.

By adopting the technical scheme, the triethanolamine and the triisopropanolamine are good complexing agents, and can promote the hydration of the recycled coarse aggregate to form ettringite as soon as possible to generate a reinforcing effect. In the hydration process of the recycled coarse aggregate, iron ions, aluminum ions and the like can be complexed to form complex salt with low solubility, and the complex salt reacts with other components in the concrete to finally generate ettringite, so that the strength of the concrete is improved.

Preferably, the method comprises the following steps: the recycled fine aggregate is waste ceramic powder.

By adopting the technical scheme, the waste ceramic powder is light in weight, fine in particles, irregular in shape and rough in surface, can be filled among the recycled coarse aggregate, the recycled fine aggregate and the cement, enhances the compactness inside the concrete and is beneficial to enhancing the strength of the concrete.

In a second aspect, the present application provides a method for preparing recycled steel fiber concrete, which adopts the following technical scheme: a preparation method of recycled steel fiber concrete comprises the following steps:

s1: uniformly mixing the recycled coarse aggregate and the recycled fine aggregate to obtain a mixture A;

s2: mixing cement and water, stirring uniformly, adding the mixture A, and mixing uniformly to obtain a mixture B;

s3: and adding the micro-bead fly ash particles, the modified steel fibers and the ramie fibers into the mixture B, uniformly mixing, and adding a polycarboxylic acid water reducing agent to prepare the regenerated steel fiber concrete.

By adopting the technical scheme, the recycled coarse aggregate and the recycled fine aggregate are firstly mixed, so that the recycled fine aggregate can be filled in gaps of the recycled coarse aggregate, cement and water are stirred to facilitate uniform mixing, the effect that the recycled coarse aggregate plays a skeleton in concrete is improved, and finally the residual raw materials are added to facilitate more uniform mixing among the raw materials and enhance the strength of the concrete.

In summary, the present application includes at least one of the following beneficial technical effects:

1. according to the application, the iron phosphate and the silane coupling agent are adopted to modify the steel fiber, so that the corrosion resistance of the steel fiber can be enhanced, the roughness of the surface of the steel fiber is increased, the bonding capability between the steel fiber and cement is improved, the compressive strength and the flexural strength of concrete are improved, the 7d compressive strength can reach 35.6MPa, the 28d compressive strength can reach 56.9MPa, the 7d flexural strength can reach 11.6MPa, and the 28d flexural strength can reach 16.2 MPa.

2. The ramie fibers are preferably selected in the concrete, can be dispersed in the concrete and can also be dispersed in gaps of the steel fibers to form a net structure together with the steel fibers, so that the breaking strength of the concrete is further enhanced, and the 7d breaking strength can reach 11.6MPa and the 28d breaking strength can reach 16.2 MPa.

3. In the application, triethanolamine and triisopropanolamine are preferably selected to pretreat the recycled coarse aggregate, so that the recycled coarse aggregate is complexed with iron ions and aluminum ions, the formation of ettringite is accelerated, the gaps of the recycled coarse aggregate are reduced, and the compactness of concrete is enhanced, so that the strength of the concrete is enhanced, and the compressive strength of 7d can reach 35.6MPa, the compressive strength of 28d can reach 56.9MPa, the flexural strength of 7d can reach 11.6MPa, and the flexural strength of 28d can reach 16.2 MPa.

Detailed Description

The present application is described in further detail below with reference to specific contents.

Raw materials

The average diameter of the micro-bead fly ash particles is 1.5 mu m, and the micro-bead fly ash particles are selected from Shenzhen Dakton science and technology Limited; the corrugated steel fibers have an average length of 15mm and are selected from engineering materials, Inc., Guangda, Laiwu; the average length of the ramie fiber is 5mm, and the ramie fiber is selected from the chemical fiber company Limited in the lake Ping city landscape; the silane coupling agent is gamma (2, 3-epoxypropoxy) propyl trimethoxy silane and is selected from Jie New materials Co., Ltd, Guangzhou city; the triethanolamine is selected from chemical industry Co., Ltd; triisopropanolamine is selected from Julong chemical Co., Ltd, Yifeng county; triethylhexyl phosphoric acid is selected from Shanghai Secoii Biotech limited; the waste rubber particles had an average particle diameter of 15mm and were selected from Xinbao mechanical Co., Ltd, Dongguan city; the waste ceramic powder had an average particle size of 3mm and was selected from Chuhong ceramics Co., Ltd, Yixing.

Preparation example

Preparation example 1

A modified steel fiber is prepared by the following method:

s1: putting 10kg of steel fiber into 50L of water, performing ultrasonic treatment for 10min under the power of 470w, performing suction filtration, putting the solid into 95L of ethanol, performing ultrasonic treatment for 10min under the power of 700w, performing suction filtration, and drying the solid at the temperature of 40 ℃ for 1h to obtain first steel fiber;

s2: mixing 90L of water and 10L of ethanol, stirring for 25min to obtain a mixture, putting the first steel fiber into the mixture, adjusting the pH to 4.8 by using glacial acetic acid with the mass fraction of 98%, carrying out ultrasonic treatment for 10min at the power of 1100w, adding 6L of gamma (2, 3-epoxypropoxy) propyl trimethoxy silane, stirring for 20min at the temperature of 50 ℃, standing for 12h, cooling to 26 ℃, carrying out suction filtration, washing the solid with water for 4 times, and drying at the temperature of 40 ℃ for 4h to obtain a second steel fiber;

s3: and (3) putting the second steel fiber into 37L of 85% iron phosphate solution, stirring for 8min, soaking for 20min at the temperature of 85 ℃, taking out the second steel fiber, washing for 4 times by using water, and drying for 3h at the temperature of 40 ℃ to obtain the modified steel fiber.

Examples

Example 1

The raw material proportion of the recycled steel fiber concrete is shown in table 1.

Wherein the recycled fine aggregate is waste ceramic powder.

A preparation method of recycled steel fiber concrete comprises the following steps:

s1: uniformly mixing the recycled coarse aggregate and the recycled fine aggregate, and stirring for 15min to obtain a mixture A;

s2: mixing cement and water, stirring for 20min, adding the mixture A, and stirring for 15min to obtain a mixture B;

s3: and adding the micro-bead fly ash particles, the modified steel fibers prepared in the preparation example 1 and the ramie fibers into the mixture B, stirring for 30min, adding the polycarboxylic acid water reducing agent, and stirring for 10min to obtain the recycled steel fiber concrete.

Examples 2 to 5

The regenerated steel fiber concrete is different from the concrete in example 1 in the raw material ratio shown in table 1.

TABLE 1 EXAMPLES 1-5 blending amounts (unit: kg) of respective raw materials for recycled Steel fiber concrete

Examples 6 to 9

The regenerated steel fiber concrete is different from the concrete in example 3 in the raw material ratio shown in table 2.

TABLE 2 examples 6-9 blending amounts (unit: kg) of respective raw materials for recycled steel fiber concrete

Examples 10 to 13

The regenerated steel fiber concrete is different from the concrete in example 7 in the raw material ratio shown in Table 3.

TABLE 3 examples 10-13 blending amounts (unit: kg) of respective raw materials for recycled steel fiber concrete

Examples 14 to 17

The difference between the recycled steel fiber concrete and the recycled steel fiber concrete in example 10 is that the raw material ratio of the recycled steel fiber concrete is different, and the raw material ratio is shown in table 4.

TABLE 4 examples 14-17 blending amounts (unit: kg) of respective raw materials for recycled steel fiber concrete

Example 18

A recycled steel fiber concrete, which is different from example 15 in that recycled coarse aggregate is equivalently replaced with recycled coarse aggregate pretreated by the following method in the raw material of the steel fiber concrete: mixing 3kg of triethanolamine and 6kg of triisopropanolamine, stirring at 45 ℃ for 30min to obtain a mixture, adding 5kg of recycled coarse aggregate into the mixture, stirring for 40min, taking out the solid, washing the solid with water for 4 times, and drying at 90 ℃ for 3.5h to obtain the pretreated recycled coarse aggregate.

Example 19

A recycled steel fiber concrete, which is different from the concrete of example 18 in that ramie fibers in the raw material of the steel fiber concrete are replaced by ramie fibers pretreated by the following method in equal amount: and (3) soaking 10kg of ramie fibers in 25kg of triethylhexylphosphoric acid for 1.7h, taking out the ramie fibers, and drying at the temperature of 55 ℃ for 1.5h to obtain the pretreated ramie fibers.

Comparative example

Comparative example 1

A recycled steel fiber concrete, which is different from the concrete of example 2 in that modified steel fibers are equally replaced with steel fibers in the raw material of the steel fiber concrete.

Comparative example 2

A recycled steel fiber concrete is different from the recycled steel fiber concrete in example 2 in that long straight steel fibers with the average length of 15mm are adopted as steel fibers in the raw materials of the steel fiber concrete.

Comparative example 3

A recycled steel fiber concrete, which is different from the recycled steel fiber concrete in example 2, is characterized in that the steel fibers are cut end hook type steel fibers with the average length of 15 mm.

Comparative example 4

A recycled steel fiber concrete is different from the recycled steel fiber concrete in example 2 in that ramie fibers are not added in the raw materials of the steel fiber concrete.

Comparative example 5

A recycled steel fiber concrete, which is different from example 2 in that recycled coarse aggregate is replaced with waste rubber particles in the raw material of the steel fiber concrete in equal amount.

Comparative example 6

A recycled steel fiber concrete, which is different from example 2 in that recycled coarse aggregate is replaced with waste concrete particles in the raw material of the steel fiber concrete in equal amount.

Performance test

The following property tests were carried out on the recycled steel fiber concretes of examples 1 to 19 and comparative examples 1 to 6:

compressive strength: the compressive strength of the recycled steel fiber concrete is detected according to GB/T50107-2010 concrete strength test evaluation Standard, and the detection result is shown in Table 5.

Breaking strength: the breaking strength of the recycled steel fiber concrete is detected according to GB/T50081-2019 'test method Standard for physical and mechanical Properties of concrete', and the detection results are shown in Table 5.

TABLE 5 test results

As can be seen from Table 5, the recycled steel fiber concrete has good compressive strength and flexural strength through the synergistic effect of the raw materials, wherein the compressive strength at 7d is 25.3-35.6MPa, the compressive strength at 28d is 44.5-56.9MPa, the flexural strength at 7d is 6.8-11.6MPa, and the flexural strength at 28d is 11.5-16.2 MPa.

Combining example 2 and comparative example 1, it can be seen that the compressive strength at 7d of example 2 is 25.3MPa, the compressive strength at 28d of 44.5MPa, the flexural strength at 7d of 6.8MPa and the flexural strength at 28d of 11.5MPa, which are superior to those of comparative example 1, indicating that the modified steel fiber is more suitable for use in example 2, and the recycled steel fiber concrete can exhibit superior compressive strength and flexural strength.

By combining example 2 with comparative examples 2 and 3, it can be seen that the compressive strength at 7d in example 2 is 25.3MPa, the compressive strength at 28d is 44.5MPa, the flexural strength at 7d is 6.8MPa, and the flexural strength at 28d is 11.5MPa, which is superior to other examples, and shows that the corrugated steel fibers are more suitable for the steel fibers in example 2, and the recycled steel fiber concrete can show superior compressive strength and flexural strength.

Combining example 2 and comparative example 4, it can be seen that the compressive strength at 7d in example 2 is 25.3MPa, the compressive strength at 28d is 44.5MPa, the flexural strength at 7d is 6.8MPa, and the flexural strength at 28d is 11.5MPa, which is better than that in comparative example 4, indicating that the addition of ramie fibers to the raw materials of the concrete in example 2 is more suitable, and the recycled steel fiber concrete can show better compressive strength and flexural strength.

In combination with 2 and comparative examples 5 and 6, it can be seen that the compressive strength at 7d in example 2 is 25.3MPa, the compressive strength at 28d is 44.5MPa, the flexural strength at 7d is 6.8MPa, and the flexural strength at 28d is 11.5MPa, which is superior to other examples, and shows that the steel fibers in example 2 are more suitable for using waste concrete particles and waste rubber particles as recycled coarse aggregates, so that the recycled steel fiber concrete can show better compressive strength and flexural strength.

In combination with examples 1-5, it can be seen that the compressive strength at 7d in example 3 is 29.9MPa, the compressive strength at 28d is 48.1MPa, the flexural strength at 7d is 7.2MPa, and the flexural strength at 28d is 12.3MPa, which is superior to other examples, and it is shown that the weight ratio of the steel fiber and the cement in example 3 is more appropriate, so that the recycled steel fiber concrete can show better compressive strength.

In combination with examples 6-9, it can be seen that the compressive strength at 7d in example 7 is 30.0MPa, the compressive strength at 28d is 51.3MPa, the flexural strength at 7d is 9.7MPa, and the flexural strength at 28d is 14.8MPa, which is superior to other examples, and it is shown that the weight ratio of the steel fiber and the ramie fiber in example 7 is more appropriate, so that the recycled steel fiber concrete can exhibit better compressive strength and flexural strength.

In combination with examples 10 to 13, it can be seen that the compressive strength at 7d in example 10 is 32.2MPa, the compressive strength at 28d is 53.4MPa, the flexural strength at 7d is 9.7MPa, and the flexural strength at 28d is 14.8MPa, which is superior to other examples, and it is shown that the weight ratio of the waste rubber particles to the waste concrete particles in the recycled coarse aggregate in example 10 is more appropriate, and the recycled steel fiber concrete can exhibit superior compressive strength.

It can be seen from the combination of examples 14-17 that the weight ratio of the micro-bead fly ash particles, the recycled fine aggregate, the polycarboxylic acid water reducing agent and the water has little influence on the compressive strength and the flexural strength of the concrete.

Combining example 15 with example 18, it can be seen that the compressive strength at 7d of example 18 is 35.6MPa, the compressive strength at 28d of example 18 is 56.9MPa, the flexural strength at 7d of example 9.7MPa, and the flexural strength at 28d of example 18 is 14.6MPa, which is superior to example 15, indicating that the recycled steel fiber concrete using the pretreated recycled coarse aggregate in example 18 is more suitable for exhibiting superior compressive strength.

Combining example 18 and example 19, it can be seen that example 19 has a compressive strength of 35.6MPa at 7d, a compressive strength of 56.9MPa at 28d, a flexural strength of 11.6MPa at 7d and a flexural strength of 16.2MPa at 28d, which is superior to example 18, indicating that the pretreated ramie fibers are more suitable for use in example 19, and the recycled steel fiber concrete can show superior flexural strength.

The embodiments of the present invention are preferred embodiments of the present application, and the scope of the present application is not limited by the embodiments of the present application, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims (10)

1. The recycled steel fiber concrete is characterized by comprising the following raw materials in parts by weight: 350 parts of cement, 60-100 parts of microbead fly ash particles, 10-30 parts of modified steel fibers, 4-12 parts of ramie fibers, 900 parts of regenerated coarse aggregate, 600 parts of regenerated fine aggregate, 2-10 parts of a polycarboxylic acid water reducing agent and 220 parts of water 150;

the modified steel fiber is prepared by modifying the steel fiber by adopting ferric phosphate and a silane coupling agent.

2. The recycled steel fiber concrete of claim 1, which is prepared from the following raw materials in parts by weight: 320 parts of cement, 280-85 parts of microbead fly ash particles, 15-21 parts of modified steel fibers, 7-10.5 parts of ramie fibers, 950-1120 parts of regenerated coarse aggregate, 680-1050 parts of regenerated fine aggregate, 5-8 parts of a polycarboxylic acid water reducing agent and 180-200 parts of water.

3. The recycled steel fiber concrete of claim 1, wherein: the addition amount of the modified steel fiber is 6-8wt% of the cement.

4. The recycled steel fiber concrete of claim 1, wherein: the weight ratio of the ramie fibers to the steel fibers is 1: (2-4).

5. The recycled steel fiber concrete of claim 1, wherein: the steel fiber is a corrugated steel fiber.

6. The recycled steel fiber concrete of claim 1, wherein: the ramie fiber is pretreated by triethylhexylphosphoric acid before use.

7. The recycled steel fiber concrete of claim 1, wherein: the recycled coarse aggregate comprises waste rubber particles and waste concrete particles, and the weight ratio of the waste rubber particles to the waste concrete particles is 1: (2-3).

8. The recycled steel fiber concrete of claim 1, wherein: the recycled coarse aggregate is pretreated by triethanolamine and triisopropanolamine before use.

9. The recycled steel fiber concrete of claim 1, wherein: the recycled fine aggregate is waste ceramic powder.

10. A method for producing recycled steel fibre concrete according to any one of claims 1 to 9, characterised in that it comprises the following steps:

s1: uniformly mixing the recycled coarse aggregate and the recycled fine aggregate to obtain a mixture A;

s2: mixing cement and water, stirring uniformly, adding the mixture A, and mixing uniformly to obtain a mixture B;

s3: and adding the micro-bead fly ash particles, the modified steel fibers and the ramie fibers into the mixture B, uniformly mixing, and adding a polycarboxylic acid water reducing agent to prepare the regenerated steel fiber concrete.