CN116730689A - Basalt fiber reinforced coral sand concrete and preparation method thereof - Google Patents

Abstract

The invention discloses basalt fiber reinforced coral sand concrete and a preparation method thereof, wherein the basalt fiber reinforced coral sand concrete comprises 220-260 parts of cement, 182-202 parts of fly ash, 38-58 parts of slag powder, 518-538 parts of coral sand, 114.8-134.8 parts of seawater, 0.40-1.2 parts of polycarboxylate water reducer and 2.11-8.44 parts of basalt fiber. The preparation method comprises the steps of mixing cement, fly ash and slag powder into a cementing material, stirring with 2/3 seawater, stirring with a polycarboxylic acid water reducer and 1/3 seawater to obtain a cementing slurry, mixing basalt fibers and coral sand, stirring, blending into the cementing slurry, pouring into a mould, and curing to obtain the concrete. The concrete has excellent impact toughness, freeze-thawing corrosion resistance, corrosion resistance and durability, and can ensure the safety and reliability of building structures while having good workability.

Description

Basalt fiber reinforced coral sand concrete and preparation method thereof

Technical field

The invention relates to the technical field of concrete, and in particular to a basalt fiber reinforced coral sand concrete and a preparation method thereof.

Background technique

Since my country proposed relevant marine strategies, the construction of island and reef projects has been in full swing. Rapid development has been achieved in the fields of infrastructure construction, marine island and reef projects, etc., and the required building materials have also continued to increase year by year. However, transporting a large amount of raw materials requires huge costs. The South China Sea islands and reefs have an important impact on my country's politics, economy and culture. In order to further develop the marine economy, the construction of the South China Sea islands and reefs needs to be steadily advanced. Structures in the South China Sea islands and reefs will be eroded by seawater, impacted by waves and denuded by sea winds. Therefore, the building materials (such as concrete) used in the construction of South China Sea islands and reefs need to have stronger mechanical properties than ordinary building materials ( Especially impact resistance), penetration resistance and corrosion resistance, the dynamic mechanical properties of building materials also need to be considered. In the construction of islands and reefs in the South China Sea, using seawater to prepare coral sand cement-based composite materials can greatly reduce project costs and reduce dependence on building materials. It has important engineering practical value. However, due to the high brittleness of coral sand, it has great impact on concrete. Intensity can have a negative impact.

In order to make full use of seawater and sand resources, a large number of scholars have conducted research on seawater and sea-sand concrete. The coarse aggregate is ordinary gravel. Studies have shown that seawater and sea sand contain more chlorine salts, which will affect the hydration process of cement. The strength, working performance and durability of concrete all have an impact. The mechanical properties of seawater and sea sand concrete are different from those of ordinary concrete. Alhozaimy et al. prepared polypropylene fiber reinforced concrete and studied its flexural toughness and impact resistance mechanical properties. The test results show that adding polypropylene fiber has little effect on the compressive strength and flexural strength of concrete. Soroushian et al. conducted freeze-thaw durability tests on carbon fiber reinforced cement-based composite materials prepared with different carbon fiber contents and different aggregate contents. The test results found that as the carbon fiber content and aggregate content continued to increase, the freeze-thaw durability of the composite materials showed an improvement. According to the law of increase and then decrease, when the carbon fiber content and aggregate content increase to a certain level, it will have a negative effect on the durability of the composite material. In addition, Zhu Deju et al. conducted experiments to analyze the influencing factors on the mechanical properties of seawater and sea sand ultra-high performance concrete without coarse aggregate, and found that steel fiber has a significant improvement effect on the mechanical properties of sea water and sea sand ultra-high performance concrete, but its It only improves the impact of compressive strength, and its impact toughness, corrosion resistance, ductility, and durability effects have yet to be explored.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a method that can improve the impact toughness, freeze-thaw erosion resistance, and corrosion resistance of concrete, effectively extend the service life of concrete, and improve the durability of concrete in the marine environment. Properties of basalt fiber reinforced coral sand concrete and preparation method thereof.

In order to solve the above technical problems, the present invention proposes the following solutions.

A kind of basalt fiber reinforced coral sand concrete is prepared from the following raw materials: in terms of mass parts, 220 to 260 parts of cement, 182 to 202 parts of fly ash, 38 to 58 parts of slag powder, and 518 to 518 parts of coral sand. 538 parts, seawater 114.8 to 134.8 parts, polycarboxylate water reducing agent 0.40 to 1.2 parts, basalt fiber 2.11 to 8.44 parts.

For the above-mentioned basalt fiber reinforced coral sand concrete, preferably, the particle size of the coral sand is 0.15 mm to 2.36 mm, and the fineness modulus of the coral sand is 1.88 to 2.03.

For the above-mentioned basalt fiber reinforced coral sand concrete, preferably, the elastic modulus of the basalt fiber is 91GPa~110GPa, the nominal length is 10mm, the density is 2.63g/ ^cm3 ~2.65g/ ^cm3 , and the single filament diameter is 7μm~15μm , breaking strength>2000MPa.

For the above-mentioned basalt fiber reinforced coral sand concrete, preferably, the solid content of the polycarboxylate water-reducing agent is 50%, the water-reducing rate is 28%, and the quality of the polycarboxylate water-reducing agent is cement, fly ash and 0.2% of the total mass of slag powder.

For the above-mentioned basalt fiber reinforced coral sand concrete, preferably, the cement is Portland cement, the fly ash has a specific surface area of 1300m ² /kg, a loss on ignition of 2.8%, a density of 2.55g/cm ³ and a SiO ₂ content 45.1% fly ash, moisture content 0.85%, fineness 16%. The slag powder has a specific surface area of 628m ² /kg, a density of 2.93g/cm ³ , a loss on ignition of 0.96%, and a moisture content of 0.4%.

For the above-mentioned basalt fiber reinforced coral sand concrete, preferably, the seawater is artificial seawater, and the artificial seawater includes NaCl, MgCl ₂ ·6H ₂ O, Na ₂ SO ₄ , CaCl ₂ , KCl, NaHCO ₃ , KBr and water.

As a general inventive concept, the present invention also provides a method for preparing the above-mentioned basalt fiber reinforced coral sand concrete, which includes the following steps:

(1) Mix and stir cement, fly ash and slag powder to obtain cementitious material;

(2) First mix the gelling material with 2/3 seawater and stir, then add polycarboxylate water-reducing agent and 1/3 seawater and continue stirring to obtain a gelled slurry;

(3) Mix the basalt fiber and coral sand and stir evenly so that the basalt fiber is evenly dispersed in the coral sand to obtain a mixture, and then fully integrate the mixture into the gelled slurry obtained in step (2) and stir to obtain a concrete material;

(4) Pour the obtained concrete material into the mold and perform curing to obtain basalt fiber reinforced coral sand concrete.

For the above preparation method of basalt fiber reinforced coral sand concrete, preferably, in step (1), the stirring time is 1 min to 3 min; in step (2), the stirring time is 2 min to 3 min, and the continuing The stirring time is 2 to 3 minutes; in step (3), the stirring time is 3 to 4 minutes.

In the above preparation method of basalt fiber reinforced coral sand concrete, preferably, in step (3), the coral sand is pre-wetted before mixing.

As a general inventive concept, the present invention also provides an application of the above-mentioned basalt fiber-reinforced coral sand concrete or the basalt fiber-reinforced coral sand concrete prepared by the above-mentioned preparation method in the field of marine engineering (preferably the field of South China Sea marine engineering).

In the present invention, the water-cement ratio is the mass ratio of seawater to cementitious materials.

Compared with the prior art, the advantages of the present invention are:

1. The basalt fiber reinforced coral sand concrete of the present invention combines basalt fiber, coral sand, polycarboxylate superplasticizer and other raw materials and their proportions to effectively improve the impact toughness, freeze-thaw erosion resistance, and corrosion resistance of the concrete. It can also extend the service life of concrete, improve the durability of concrete in the marine environment, and expand its application scope in the marine field. The present invention uses coral sand in seawater as raw material, which can be obtained locally during the construction process of marine projects. It not only reduces the cost of raw materials, but also reduces the cost of transporting fresh water and sand from the inland. However, using coral sand as fine material Aggregate will cause many defects such as micro-cracks and micro-voids in the test block, making the tensile strength and impact strength low and brittle. For concrete, the damaged and fragile areas are often between the cement slurry and the aggregate. In the interface transition zone, the applicant found that incorporating basalt fiber can improve the strength of the microstructure of the interface transition zone, reduce defects within the concrete, improve the compactness and integrity of the concrete, and significantly improve the impact resistance toughness of the concrete, solving the problem Due to the adverse effects of the brittleness of coral sand on the strength of concrete, the resulting concrete has good workability while ensuring the safety and reliability of the building structure. Different basalt fiber content has a significant impact on the dynamic impact characteristics of concrete. Appropriate basalt fiber content can effectively reduce the damage and deterioration of concrete. The synergy of coral sand and basalt fiber can also significantly improve the freeze-thaw erosion resistance of concrete under corrosive conditions and effectively extend its service life.

2. The polycarboxylate water-reducing agent used in the basalt fiber reinforced coral sand concrete of the present invention can ensure a very low water-cement ratio (the water-cement ratio of ordinary concrete is usually between 0.35-0.6, and the water-cement ratio of the present invention is The glue ratio is between 0.22-0.3), so that the mixture has good working performance and obtains concrete with excellent mechanical properties, ductility and durability that meets the structural requirements.

3. The basalt fiber reinforced coral sand concrete of the present invention also adds slag powder, fly ash and other cementitious materials, which can improve the strength of the microstructure of the interface transition zone to a certain extent, enhance the durability and long-term strength of the concrete, and at the same time The coarse aggregates such as gravel commonly used in existing concrete materials are eliminated, and coral sand is used as fine aggregate. After adding basalt fiber, the density and integrity of the concrete are improved, and the internal defects of the concrete are reduced. Therefore, multiple raw materials are synergistic. It can significantly improve the strength and durability of concrete and make concrete more adaptable to the marine environment.

4. The preparation method of the present invention rationally adds high-quality mineral admixtures or composite admixtures through the selection and proportion control of raw materials and the optimization control of construction processes. The use of coral sand fine aggregate can obtain local materials and reduce costs. , but it will lead to many defects such as micro-cracks and micro-voids in the test block. Improving the strength of the microstructure in the interface transition zone by incorporating basalt fiber can significantly improve the impact toughness of concrete and solve the problem of tensile strength of coral sand cement-based materials. To solve the problem of low water-binder ratio and brittle nature, the use of polycarboxylate water-reducing agent can ensure that the mixture has good working performance at an extremely low water-binder ratio and obtains the mechanical properties, ductility, and durability required by the structure. Excellent concrete. The present invention adopts the fiber post-mixing method to promote the fibers to be dispersed more evenly in the concrete.

5. The basalt fiber reinforced coral sand concrete of the present invention can be used in the field of marine engineering, solves the problem of impact resistance and toughness of ordinary concrete in marine environments, and has high economic benefits in marine engineering.

Description of drawings

Figure 1 is an SEM image of the connection between the coral sand and the concrete matrix in the basalt fiber reinforced coral sand concrete of Example 2.

Figure 2 is an SEM image of the connection between the end of the basalt fiber and the concrete matrix in the basalt fiber reinforced coral sand concrete of Example 2.

Figure 3 is an SEM image of the three-dimensional skeleton bridge of basalt fiber in the basalt fiber reinforced coral sand concrete of Example 2.

Figure 4 is an SEM image of the fracture of basalt fibers in the basalt fiber reinforced coral sand concrete of Example 2.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments of the specification, but the protection scope of the present invention will not be limited thereby. The materials and instruments used in the following examples are all commercially available.

In the following examples:

The cement is PO42.5 Portland cement produced by Zhucheng Yangchun Shanshui Cement Co., Ltd. The fly ash has a specific surface area of ^1300m2 /kg, a loss on ignition of 2.8%, a density of 2.55g/ ^cm3 , and a _SiO2 content of 45.1%. The fly ash has a moisture content of 0.85% and a fineness of 16%. The slag powder has a specific surface area of 628m ² /kg, a density of 2.93g/cm ³ , a loss on ignition of 0.96%, and a moisture content of 0.4%.

Coral sand is used as the fine aggregate of concrete. The particle size of coral sand is 0.15mm~2.36mm, the fineness modulus is 1.88~2.03, and it is classified as fine sand.

The elastic modulus of basalt fiber is 91~110GPa, the nominal length is 10mm, the density is 2.64g/cm ³ (2.63g/cm ³ ~ 2.65g/cm ³ is acceptable), the single filament diameter is 7μm~15μm, and the breaking strength is >2000MPa . The present invention uses basalt fiber as reinforcing material, which can effectively increase the compressive strength of concrete, improve the compression and crack resistance of concrete, and at the same time increase the ductility and durability of coral sand concrete.

The solid content of the polycarboxylate water-reducing agent is 50%, the water-reducing rate is 28%, and the mass of the polycarboxylate water-reducing agent is 0.2% of the total mass of cement, fly ash and slag powder. The present invention uses polycarboxylate water-reducing agent to improve the construction performance and hardening performance of concrete, save cement, reduce energy consumption, and improve the density of concrete. The improvement in density can effectively prevent the erosion of chloride ions, thereby enhancing the chlorine resistance of concrete. Ion permeability, while increasing density can also improve the mechanical properties of concrete.

Seawater, used as water for hydration reaction, is artificial seawater configured in proportion. Artificial seawater contains water and the chemical composition shown in Table 1.

Table 1 Chemical composition of artificial seawater

Example 1

A kind of basalt fiber reinforced coral sand concrete of the present invention is composed of the following components in terms of parts by mass: 240 parts of Portland cement, 192 parts of fly ash, 48 parts of slag powder, 528 parts of coral sand, 124.8 parts of seawater, The polycarboxylate water-reducing agent is 0.96 parts and the basalt fiber is 2.11 parts.

A method for preparing the basalt fiber reinforced coral sand concrete of this embodiment includes the following steps:

(1) Wet the wall of the mixing barrel, add cement, fly ash and slag powder, stir for 1 minute until uniform, and obtain the cementitious material; artificial seawater can be prepared in advance.

(2) Add 2/3 seawater into the mixing barrel, mix with the gelling material and stir for about 2 minutes, then add polycarboxylate superplasticizer and 1/3 seawater and stir for about 2 minutes to obtain a gelled slurry with certain fluidity body.

(3) Stir the basalt fiber and coral sand evenly in advance so that the basalt fiber is evenly dispersed in the coral sand to obtain a mixture. Fully integrate the mixture of coral sand and basalt fiber into the gelled slurry and stir for 3 minutes to obtain concrete material.

(4) Pour the concrete material into the mold and vibrate for 1 minute. After 24 hours, remove the mold and perform standard curing to 28 days to obtain basalt fiber reinforced coral sand concrete.

The cured concrete test blocks were subjected to static compression tests and dynamic impact compression SHPB tests. The results are shown in Table 2.

Example 2

A kind of basalt fiber reinforced coral sand concrete of the present invention is composed of the following components in terms of parts by mass: 240 parts of Portland cement, 192 parts of fly ash, 48 parts of slag powder, 528 parts of coral sand, 124.8 parts of sea water, 0.96 parts of polycarboxylate water-reducing agent and 4.22 parts of basalt fiber.

A method for preparing the basalt fiber reinforced coral sand concrete of this embodiment includes the following steps:

(1) Wet the wall of the mixing barrel, add cement, fly ash and slag powder, stir for 1 minute until uniform, and obtain the cementitious material; artificial seawater can be prepared in advance.

(2) Add 2/3 of the seawater into the mixing barrel, mix with the gelling material and stir for about 2 minutes, then add polycarboxylate superplasticizer and 1/3 of the seawater and stir for about 2 minutes to obtain a gelatinous material with certain fluidity. slurry.

(3) Stir the basalt fiber and coral sand evenly in advance so that the basalt fiber is evenly dispersed in the coral sand to obtain a mixture. Fully integrate the mixture of coral sand and basalt fiber into the gelled slurry and stir for 3 minutes to obtain concrete material.

(4) Pour the concrete material into the mold and vibrate for 1 minute. After 24 hours, remove the mold and perform standard curing to 28 days to obtain basalt fiber reinforced coral sand concrete.

The cured concrete test blocks were subjected to static compression tests and dynamic impact compression SHPB tests. The results are shown in Table 2.

Figure 1 is an SEM image of the connection between the coral sand and the concrete matrix in the basalt fiber reinforced coral sand concrete of this embodiment. It can be seen from the figure that coral sand has a porous internal structure and is more likely to break under external force.

Figure 2 is an SEM image of the connection between the end of the basalt fiber and the concrete matrix in the basalt fiber reinforced coral sand concrete of this embodiment. It can be seen from the figure that the holes of basalt fiber reinforced coral sand concrete are filled with hydration products, and the basalt fiber matrix is wrapped by cement particles. There are more hydration products generated at the connection between the fiber surface and fiber roots and the concrete matrix. .

Figure 3 is an SEM image of the three-dimensional skeleton bridge of basalt fiber in the basalt fiber reinforced coral sand concrete of this embodiment. It can be seen from the figure that basalt fiber forms a three-dimensional skeleton network system in the concrete matrix, which is relatively stable in the concrete matrix and restrains the deformation of the concrete material. This shows that basalt fiber can enhance the strength of concrete.

Figure 4 is an SEM image of the fracture of basalt fibers in the basalt fiber reinforced coral sand concrete of this embodiment. It can be seen in the figure that the fiber fractures show a cross-tear shape, which shows that the bonding performance between the basalt fiber and the concrete matrix is good, and also shows that the basalt fiber plays a very good restraint role in the destruction of the concrete matrix.

Example 3

A kind of basalt fiber reinforced coral sand concrete of the present invention is composed of the following components in terms of parts by mass: 240 parts of Portland cement, 192 parts of fly ash, 48 parts of slag powder, 528 parts of coral sand, 124.8 parts of seawater, Polycarboxylate water-reducing agent 0.96 parts, basalt fiber 8.44 parts.

A method for preparing the basalt fiber reinforced coral sand concrete of this embodiment includes the following steps:

(1) Wet the wall of the mixing barrel, add cement, fly ash and slag powder, stir for 1 minute until uniform, and obtain the cementitious material; artificial seawater can be prepared in advance.

(2) Add 2/3 of the seawater into the mixing barrel, mix with the gelling material and stir for about 2 minutes, then add polycarboxylate superplasticizer and 1/3 of the seawater and stir for about 2 minutes to obtain a gelatinous material with certain fluidity. slurry.

(3) Stir the basalt fiber and coral sand evenly in advance so that the basalt fiber is evenly dispersed in the coral sand to obtain a mixture. Fully integrate the mixture of coral sand and basalt fiber into the gelled slurry and stir for 3 minutes to obtain concrete material.

(4) Pour the concrete material into the mold and vibrate for 1 minute. After 24 hours, remove the mold and perform standard curing to 28 days to obtain basalt fiber reinforced coral sand concrete.

The cured concrete test blocks were subjected to static compression tests and dynamic impact compression SHPB tests. The results are shown in Table 2.

Comparative example 1

A kind of basalt fiber reinforced coral sand concrete consists of the following components in terms of parts by mass: 240 parts of Portland cement, 192 parts of fly ash, 48 parts of slag powder, 528 parts of coral sand, 124.8 parts of seawater, polycarboxylic acid 0.96 parts of water reducing agent and 4.22 parts of basalt fiber.

A preparation method of basalt fiber reinforced coral sand concrete, including the following steps:

(1) Wet the wall of the mixing barrel, add cement, fly ash and slag powder, stir for 1 minute until uniform, and obtain the cementitious material; artificial seawater can be prepared in advance.

(2) Add 2/3 of the seawater into the mixing barrel, mix with the gelling material and stir for about 2 minutes, then add polycarboxylate superplasticizer and 1/3 of the seawater and stir for about 2 minutes to obtain a gelatinous material with certain fluidity. slurry.

(3) Add coral sand to the gelled slurry and stir until the coral sand is fully integrated into the gelled slurry to obtain a material mixture.

(4) Mix basalt fiber into the material mixture and disperse it evenly to obtain concrete material.

(5) Pour the concrete material into the mold and vibrate for 1 minute. After 24 hours, remove the mold and perform standard curing to 28 days to obtain basalt fiber reinforced coral sand high ductility concrete.

The cured concrete test blocks were subjected to static compression tests and dynamic impact compression SHPB tests. The results are shown in Table 2.

Comparative example 2

A kind of carbon fiber reinforced coral sand concrete consists of the following components in terms of parts by mass: 240 parts of Portland cement, 192 parts of fly ash, 48 parts of slag powder, 528 parts of coral sand, 124.8 parts of seawater, polycarboxylic acid-reduced 0.96 parts of water agent and 8.44 parts of carbon fiber.

A preparation method of carbon fiber reinforced coral sand concrete, including the following steps:

(1) Pre-wet the coral sand to saturation 24 hours in advance before preparation, and prepare seawater artificially in advance.

(2) First stir the Portland cement, fly ash and slag powder evenly, add 2/3 of the seawater and stir for about 2 minutes, then add the polycarboxylate superplasticizer and 1/3 of the seawater and stir for about 2 minutes to get A gel-like slurry with certain fluidity.

(3) Stir the carbon fiber and coral sand evenly in advance so that the carbon fiber is evenly dispersed in the coral sand to obtain a mixture. Fully integrate the mixture of coral sand and carbon fiber into the gelled slurry and stir for 3 minutes to obtain concrete material.

(4) Pour the concrete material into the mold and vibrate for 1 minute. After 24 hours, remove the mold and perform standard curing to 28 days to obtain carbon fiber reinforced coral sand concrete.

The cured concrete test blocks were subjected to static compression tests and dynamic impact compression SHPB tests. The results are shown in Table 2.

Comparative example 3

Coral sand concrete without basalt fiber, that is, the blank group, is as follows:

A kind of coral sand concrete consists of the following components in terms of parts by mass: 240 parts of Portland cement, 192 parts of fly ash, 48 parts of slag powder, 528 parts of coral sand, 124.8 parts of seawater, and polycarboxylate water-reducing agent 0.96 servings.

A preparation method of coral sand concrete includes the following steps:

(1) Pre-wet the coral sand to saturation 24 hours in advance before preparation, and prepare seawater artificially in advance.

(2) First stir the Portland cement, fly ash and slag powder evenly, add 2/3 of the seawater and stir for about 2 minutes, then add the polycarboxylate superplasticizer and 1/3 of the seawater and stir for about 2 minutes to get A gel-like slurry with certain fluidity.

(3) Add coral sand to the gelled slurry and stir until the coral sand is fully integrated into the gelled slurry to obtain concrete material.

(4) Pour the concrete material into the mold and vibrate it for 1 minute. After 24 hours, remove the mold and perform standard curing to 28 days to obtain coral sand concrete.

The cured concrete test blocks were subjected to static compression tests and dynamic impact compression SHPB tests. The results are shown in Table 2.

Table 2 Static and dynamic compressive strength of concrete in Examples 1-3 and Comparative Examples 1-3

The above descriptions are only preferred embodiments of the present invention and do not limit the present invention in any form. Although the present invention has been disclosed above in terms of preferred embodiments, this is not intended to limit the present invention. Any person familiar with the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical content disclosed above without departing from the spirit and technical solution of the present invention, or modify it to be equivalent. Varied equivalent embodiments. Therefore, any simple modifications, equivalent substitutions, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims (7)

1. A kind of basalt fiber reinforced coral sand concrete, characterized in that it is prepared from the following raw materials: in terms of parts by mass, 220 to 260 parts of cement, 182 to 202 parts of fly ash, and 38 to 58 parts of slag powder , 518 to 538 parts of coral sand, 114.8 to 134.8 parts of sea water, 0.40 to 1.2 parts of polycarboxylate water-reducing agent, 2.11 to 8.44 parts of basalt fiber; The particle size of the coral sand is 0.15mm~2.36mm, and the fineness modulus of the coral sand is 1.88~2.03; The elastic modulus of the basalt fiber is 91GPa~110GPa, the nominal length is 10mm, the density is 2.63g/ ^cm3 ~2.65g/ ^cm3 , the single filament diameter is 7μm~15μm, and the breaking strength is >2000MPa; The solid content of the polycarboxylate water-reducing agent is 50%, and the water-reducing rate is 28%. 2. The basalt fiber reinforced coral sand concrete according to claim 1, characterized in that the mass of the polycarboxylate water-reducing agent is 0.2% of the total mass of cement, fly ash and slag powder. 3. The basalt fiber reinforced coral sand concrete according to claim 1 or 2, characterized in that the cement is Portland cement, the fly ash has a specific surface area of ^1300m2 /kg, a loss on ignition of 2.8%, Fly ash with a density of 2.55g/cm ³ , a SiO ₂ content of 45.1%, a moisture content of 0.85%, and a fineness of 16%. The slag powder has a specific surface area of 628m ² /kg, a density of 2.93g/cm ³ , and a loss on ignition of 0.96 %, slag powder with moisture content of 0.4%. 4. The basalt fiber reinforced coral sand concrete according to claim 1 or 2, characterized in that the seawater is artificial seawater, and the artificial seawater includes NaCl, MgCl ₂ ·6H ₂ O, Na ₂ SO ₄ , CaCl ₂ , KCl, NaHCO ₃ , KBr and water. 5. A method for preparing the basalt fiber reinforced coral sand concrete according to any one of claims 1 to 4, characterized in that it includes the following steps: (1) Mix and stir cement, fly ash and slag powder to obtain cementitious material; (2) First mix the gelling material with 2/3 seawater and stir, then add polycarboxylate water-reducing agent and 1/3 seawater and continue stirring to obtain a gelled slurry; (3) Mix the basalt fiber and coral sand and stir evenly so that the basalt fiber is evenly dispersed in the coral sand to obtain a mixture, and then fully integrate the mixture into the gelled slurry obtained in step (2) and stir to obtain a concrete material; (4) Pour the obtained concrete material into the mold and perform curing to obtain basalt fiber reinforced coral sand concrete. 6. The preparation method of basalt fiber reinforced coral sand concrete according to claim 5, characterized in that in step (1), the stirring time is 1 min to 3 min; in step (2), the stirring time is 2min～3min, and the time for continuing stirring is 2min～3min; in step (3), the time for stirring is 3min～4min. 7. The preparation method of basalt fiber reinforced coral sand concrete according to claim 5 or 6, characterized in that in step (3), the coral sand is pre-wetted before mixing.