A modified basalt fiber and its preparation method and application

Abstract

The present invention discloses a modified basalt fiber and a preparation method and application thereof, and belongs to the technical field of fiber preparation. The modified basalt fiber preparation method is as follows: calcium carbonate is dispersed in water, polyethyleneimine is added to react to obtain calcium carbonate / PEI; then methyl acrylate and ethylenediamine are used as modifiers in turn, and calcium carbonate / PEI / PAMAM‑1 is obtained by reaction; step 1.2 is repeated to prepare calcium carbonate / PEI / PAMAM‑2; it is mixed with an organic compound and an organic solvent to obtain a slurry for standby use; after removing impurities on the surface of the original basalt fiber, a pretreated basalt fiber is obtained, and the pretreated basalt fiber is immersed in a hydrochloric acid solution, and the acid-treated basalt fiber is immersed at 30‑40°C to obtain an acid-treated basalt fiber; the acid-treated basalt fiber is immersed in the slurry, and the modified basalt fiber is obtained by room temperature immersion. The modified basalt fiber prepared by the present invention can improve the crack resistance and compressive strength of concrete.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber preparation, and more specifically to a modified basalt fiber and a preparation method and application thereof. Background Art

[0002] Concrete is a general term for engineering composite materials in which aggregates are bonded into a whole by cementitious materials. According to the cementitious materials, it can be divided into inorganic cementitious concrete and organic cementitious concrete. Inorganic cementitious concrete includes lime-silica cementitious concrete (such as silicate concrete), silicate cement concrete (such as ordinary cement, slag cement, etc.), calcium-aluminum cement concrete (such as high-aluminum cement, ultra-fast hard cement concrete, etc.), gypsum concrete, magnesium cement concrete, sulfur concrete, water glass sodium fluorosilicate concrete, metal concrete, etc. Organic cementitious concrete mainly includes asphalt concrete and polymer cement concrete, resin concrete, polymer impregnated concrete, etc. In addition, inorganic and organic composite colloidal concrete can also be divided into polymer cement concrete and polymer indigo concrete.

[0003] Concrete has been increasingly widely used in housing, roads, bridges, airports, and water conservancy projects due to its mechanical properties, durability, economy, easy access to raw materials, and processing and molding. Concrete is a brittle material with low tensile strength and low ultimate elongation, and it is easy to crack during construction and service. Adding fiber to concrete is one of the effective measures to improve the crack resistance of concrete. Basalt fiber is formed by melting volcanic rock at 1450-1500℃ and drawing it through a leaky plate process. The chemical composition of basalt fiber is very similar to that of ordinary synthetic glass fiber. Its basic components are silica, alumina, calcium oxide, etc. Therefore, in many cases, basalt fiber is an alternative material to glass fiber and carbon fiber.

[0004] As a high-performance fiber, basalt fiber has many advantages over other fibers, including large elastic modulus, good tensile strength, good heat resistance, acid resistance, alkali resistance, wear resistance and corrosion resistance, as well as good insulation and radiation resistance. However, the surface of basalt fiber is inert and smooth, and it cannot be perfectly combined with cement paste, so it is difficult to exert its excellent performance when combined with other materials. Summary of the invention

[0005] In view of the above problems, the present invention provides a modified basalt fiber and a preparation method and application thereof. The modified basalt fiber can improve the crack resistance and compressive strength of concrete.

[0006] The first object of the present invention is to provide a method for preparing modified basalt fiber, which is prepared according to the following steps:

[0007] Step 1, preparation of calcium carbonate / PEI / PAMAM-2

[0008] Step 1.1, dispersing calcium carbonate in water, adding polyethyleneimine, and reacting at 30-40° C. to obtain calcium carbonate / PEI;

[0009] Step 1.2, using calcium carbonate / PEI as raw materials, methyl acrylate and ethylenediamine as modifiers, reacting at 35-45°C, calcium carbonate / PEI / PAMAM-1;

[0010] Step 1.3, using calcium carbonate / PEI / PAMAM-1 as raw materials, repeating step 1.2 to prepare calcium carbonate / PEI / PAMAM-2;

[0011] Step 2, mixing calcium carbonate / PEI / PAMAM-2, an organic compound and an organic solvent to obtain a slurry for standby use;

[0012] Step 3: Preparation of modified basalt fiber

[0013] Step 3.1, after removing impurities on the surface of the original basalt fiber, a pretreated basalt fiber is obtained, and the pretreated basalt fiber is immersed in a hydrochloric acid solution at 30-40° C. to obtain an acid-treated basalt fiber;

[0014] Step 3.2: Immerse the acid-treated basalt fiber in the slurry at room temperature to obtain the modified basalt fiber.

[0015] Preferably, in step 1.1, the reaction time is 10-12 hours; the addition ratio of calcium carbonate, polyethyleneimine and water is 30-50 mg:70-100 mg:100 ml.

[0016] Preferably, step 1.2 is prepared according to the following steps:

[0017] S1. Using methanol as solvent and methyl acrylate as modifier, calcium carbonate / PEI is added and reacted at 35-45°C to obtain a calcium carbonate / PEI intermediate;

[0018] S2. Using water as solvent and ethylenediamine as modifier, calcium carbonate / PEI-intermediate is added and reacted at 35-45°C to obtain calcium carbonate / PEI / PAMAM-1.

[0019] Preferably, in S1, the reaction time is 10-15h; the addition ratio of calcium carbonate / PEI, methyl acrylate, and methanol is 30-50mg:20-30ml:400ml;

[0020] In S2, the reaction time is 10-15h; the addition ratio of calcium carbonate / PEI-intermediate, ethylenediamine, and water is 30-50mg:25-35ml:400ml.

[0021] Preferably, in step 2, the ratio of calcium carbonate / PEI / PAMAM-2, organic compound, and organic solvent is 0.1-0.2 g: 0.5: 100 ml.

[0022] Preferably, in step 2, the organic compound is bisphenol A epoxy resin, and the organic solvent is acetone or ethanol.

[0023] Preferably, in step 3.1, the original basalt fiber is soaked in acetone for 2-3 hours to remove impurities on the surface of the basalt fiber to obtain pretreated basalt fiber;

[0024] Soak in a hydrochloric acid solution for 30-50 minutes. The concentration of the hydrochloric acid solution is 0.1 mol / L.

[0025] Preferably, in step 3.2, the soaking time is 15-20 seconds.

[0026] The second object of the present invention is to provide modified basalt fiber prepared by the above method.

[0027] The third object of the present invention is to provide the use of the modified basalt fiber in the preparation of concrete materials.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The invention prepares a modified basalt fiber. Firstly, calcium carbonate is modified by polyethyleneimine (PEI) so that the surface of the calcium carbonate contains amino groups. Secondary modification of the calcium carbonate is achieved by methyl acrylate and ethylenediamine. Polyamide-amine (PAMAM) dendritic macromolecules are successfully introduced on the surface of the calcium carbonate. After the surface modification of the calcium carbonate, the dispersibility of the calcium carbonate is improved, which is more conducive to introducing the calcium carbonate into the surface of the basalt fiber. The introduction of the modified calcium carbonate can effectively improve the surface roughness of the fiber. Meanwhile, after the modification, the hydrophilic groups on the fiber surface can effectively improve the hydrophilicity of the surface of the basalt fiber.

[0030] The modified basalt fiber prepared by the invention can improve the crack resistance and compressive strength of concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Figure 2 shows the compressive strength of concrete in different treatment groups. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment provides a method for preparing calcium carbonate / PEI / PAMAM-2, which is prepared specifically according to the following steps:

[0035] Step 1, weigh 30 mg of calcium carbonate and disperse it in 100 ml of water. After ultrasonic homogenization, slowly add 70 mg of polyethyleneimine under stirring, stir well, transfer to a water bath, stir at 40°C for 10 hours. After the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50°C for 6 hours to obtain calcium carbonate / PEI;

[0036] Step 2: Measure 24 ml of methyl acrylate, add it to 400 ml of methanol, stir evenly to obtain a modified solution A, then add 30 mg of calcium carbonate / PEI to the modified solution A, stir evenly, transfer to a water bath, stir at 35° C. for 12 h, after the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50° C. for 10 h to obtain a calcium carbonate / PEI intermediate;

[0037] Measure 25 ml of ethylenediamine, add it to 400 ml of water, stir evenly to obtain modified solution B, then add 30 mg of calcium carbonate / PEI-intermediate to the modified solution B, stir evenly, transfer to a water bath, stir at 35°C for 12 hours, after the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50°C for 10 hours to obtain calcium carbonate / PEI / PAMAM-1;

[0038] Step 3: Using calcium carbonate / PEI / PAMAM-1 as raw materials, repeat step 2 to prepare calcium carbonate / PEI / PAMAM-2.

[0039] Example 2

[0040] This embodiment provides a method for preparing calcium carbonate / PEI / PAMAM-2, which is prepared specifically according to the following steps:

[0041] Step 1, weigh 50 mg of calcium carbonate and disperse it in 100 ml of water. After ultrasonic homogenization, slowly add 100 mg of polyethyleneimine under stirring, stir well, transfer to a water bath, stir at 30°C for 12 hours. After the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50°C for 6 hours to obtain calcium carbonate / PEI;

[0042] Step 2: Measure 30 ml of methyl acrylate, add it to 400 ml of methanol, stir evenly to obtain a modified solution A, then add 50 mg of calcium carbonate / PEI to the modified solution A, stir evenly, transfer to a water bath, stir at 40° C. for 12 h, after the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50° C. for 10 h to obtain a calcium carbonate / PEI intermediate;

[0043] Measure 35 ml of ethylenediamine, add it to 400 ml of water, stir evenly to obtain modified solution B, then add 50 mg of calcium carbonate / PEI-intermediate to the modified solution B, stir evenly, transfer to a water bath, stir at 40°C for 12 hours, after the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50°C for 10 hours to obtain calcium carbonate / PEI / PAMAM-1;

[0044] Step 3: Using calcium carbonate / PEI / PAMAM-1 as raw materials, repeat step 2 to prepare calcium carbonate / PEI / PAMAM-2.

[0045] Example 3

[0046] This embodiment provides a method for preparing calcium carbonate / PEI / PAMAM-2, which is prepared specifically according to the following steps:

[0047] Step 1, weigh 40 mg of calcium carbonate and disperse it in 100 ml of water. After ultrasonic homogenization, slowly add 80 mg of polyethyleneimine under stirring, stir well, transfer to a water bath, stir at 35°C for 11 hours. After the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50°C for 6 hours to obtain calcium carbonate / PEI;

[0048] Step 2: Measure 20 ml of methyl acrylate, add it to 400 ml of methanol, stir evenly to obtain a modified solution A, then add 40 mg of calcium carbonate / PEI to the modified solution A, stir evenly, transfer to a water bath, stir at 45° C. for 10 h, after the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50° C. for 10 h to obtain a calcium carbonate / PEI intermediate;

[0049] 30 ml of ethylenediamine was measured and added to 400 ml of water, and the mixture was stirred to obtain a modified solution B. Then, 40 mg of calcium carbonate / PEI-intermediate was added to the modified solution B, and the mixture was stirred to obtain a modified solution B. The mixture was transferred to a water bath and stirred at 45° C. for 10 h. After the reaction was completed, the precipitate obtained by centrifugation was washed with deionized water for 3 times, and vacuum dried at 50° C. for 10 h to obtain calcium carbonate / PEI / PAMAM-1.

[0050] Step 3: Using calcium carbonate / PEI / PAMAM-1 as raw materials, repeat step 2 to prepare calcium carbonate / PEI / PAMAM-2.

[0051] Example 4

[0052] This embodiment provides a method for preparing calcium carbonate / PEI / PAMAM-2, which is prepared specifically according to the following steps:

[0053] Step 1, weigh 50 mg of calcium carbonate and disperse it in 100 ml of water. After ultrasonic homogenization, slowly add 90 mg of polyethyleneimine under stirring, stir well, transfer to a water bath, stir at 40°C for 12 hours. After the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50°C for 6 hours to obtain calcium carbonate / PEI;

[0054] Step 2: Measure 25 ml of methyl acrylate, add it to 400 ml of methanol, stir evenly to obtain a modified solution A, then add 50 mg of calcium carbonate / PEI to the modified solution A, stir evenly, transfer to a water bath, stir at 35° C. for 15 h, after the reaction is completed, wash the precipitate obtained by centrifugation with deionized water three times, and vacuum dry at 50° C. for 10 h to obtain a calcium carbonate / PEI intermediate;

[0055] Measure 25 ml of ethylenediamine, add it to 400 ml of water, stir evenly to obtain modified solution B, then add 50 mg of calcium carbonate / PEI-intermediate to the modified solution B, stir evenly, transfer to a water bath, stir at 35°C for 15 hours, after the reaction is completed, centrifuge the precipitate, wash it three times with deionized water, and vacuum dry it at 50°C for 10 hours to obtain calcium carbonate / PEI / PAMAM-1;

[0056] Step 3: Using calcium carbonate / PEI / PAMAM-1 as raw materials, repeat step 2 to prepare calcium carbonate / PEI / PAMAM-2.

[0057] Example 5

[0058] This embodiment provides a method for preparing modified basalt fiber, which is prepared specifically according to the following steps:

[0059] Step 1, placing the original basalt fiber into a beaker containing acetone, making the acetone cover the original basalt fiber, and soaking for 2 hours to remove impurities on the surface of the basalt fiber to obtain pretreated basalt fiber;

[0060] A hydrochloric acid solution with a concentration of 0.1 mol / L was prepared, and the pretreated basalt fiber was placed in the hydrochloric acid solution and soaked at 40°C for 30 minutes. After the treatment, the basalt fiber was washed with deionized water until the pH of the washing solution was 7, and then vacuum dried at 60°C to obtain the acid-treated basalt fiber.

[0061] Step 2, weigh 0.1 g of calcium carbonate / PEI / PAMAM-2 prepared in Example 1, add it to 100 ml of acetone and disperse it evenly by ultrasonication, then add 0.5 g of E-51, mix evenly by ultrasonication to obtain a slurry for later use;

[0062] The acid-treated basalt fiber is immersed in the above slurry at room temperature for 15 seconds to obtain the modified basalt fiber.

[0063] Example 6

[0064] This embodiment provides a method for preparing modified basalt fiber, which is prepared specifically according to the following steps:

[0065] Step 1, placing the original basalt fiber into a beaker containing acetone, making the acetone cover the original basalt fiber, and soaking for 2 hours to remove impurities on the surface of the basalt fiber to obtain pretreated basalt fiber;

[0066] A hydrochloric acid solution with a concentration of 0.1 mol / L was prepared, and the pretreated basalt fiber was placed in the hydrochloric acid solution and soaked at 40°C for 30 minutes. After the treatment, the basalt fiber was washed with deionized water until the pH of the washing solution was 7, and then vacuum dried at 60°C to obtain the acid-treated basalt fiber.

[0067] Step 2, weigh 0.1.5 g of calcium carbonate / PEI / PAMAM-2 prepared in Example 1, add it to 100 ml of acetone, and disperse it evenly by ultrasonication, then add 0.5 g of E-51, mix evenly by ultrasonication to obtain a slurry, and set aside;

[0068] The acid-treated basalt fiber is immersed in the above slurry at room temperature for 15 seconds to obtain the modified basalt fiber.

[0069] Example 7

[0070] This embodiment provides a method for preparing modified basalt fiber, which is prepared specifically according to the following steps:

[0071] Step 1, placing the original basalt fiber into a beaker containing acetone, making the acetone cover the original basalt fiber, and soaking for 2 hours to remove impurities on the surface of the basalt fiber to obtain pretreated basalt fiber;

[0072] A hydrochloric acid solution with a concentration of 0.1 mol / L was prepared, and the pretreated basalt fiber was placed in the hydrochloric acid solution and soaked at 40°C for 30 minutes. After the treatment, the basalt fiber was washed with deionized water until the pH of the washing solution was 7, and then vacuum dried at 60°C to obtain the acid-treated basalt fiber.

[0073] Step 2, weigh 0.2 g of calcium carbonate / PEI / PAMAM-2 prepared in Example 1, add it to 100 ml of acetone, and disperse it evenly by ultrasonication, then add 0.5 g of E-51, and mix evenly by ultrasonication to obtain a slurry for later use;

[0074] The acid-treated basalt fiber is immersed in the above slurry at room temperature for 15 seconds to obtain the modified basalt fiber.

[0075] Example 8

[0076] This embodiment provides a method for preparing modified basalt fiber, which is prepared specifically according to the following steps:

[0077] Step 1, placing the original basalt fiber into a beaker containing acetone, making the acetone cover the original basalt fiber, and soaking for 3 hours to remove impurities on the surface of the basalt fiber to obtain pretreated basalt fiber;

[0078] A hydrochloric acid solution with a concentration of 0.1 mol / L was prepared, and the pretreated basalt fiber was placed in the hydrochloric acid solution and soaked at 30°C for 50 minutes. After the treatment, the basalt fiber was washed with deionized water until the pH of the washing solution was 7, and then vacuum dried at 60°C to obtain the acid-treated basalt fiber.

[0079] Step 2, weigh 0.1 g of calcium carbonate / PEI / PAMAM-2 prepared in Example 3, add it to 100 ml of acetone and disperse it evenly by ultrasonication, then add 0.5 g of E-51, mix evenly by ultrasonication to obtain a slurry for later use;

[0080] The acid-treated basalt fiber is immersed in the above slurry at room temperature for 18 seconds to obtain the modified basalt fiber.

[0081] Example 9

[0082] This embodiment provides a method for preparing modified basalt fiber, which is prepared specifically according to the following steps:

[0083] Step 1, placing the original basalt fiber into a beaker containing acetone, making the acetone cover the original basalt fiber, and soaking for 2.5 hours to remove impurities on the surface of the basalt fiber to obtain pretreated basalt fiber;

[0084] A hydrochloric acid solution with a concentration of 0.1 mol / L was prepared, and the pretreated basalt fiber was placed in the hydrochloric acid solution and soaked at 35°C for 40 minutes. After the treatment, the basalt fiber was washed with deionized water until the pH of the washing solution was 7, and then vacuum dried at 60°C to obtain the acid-treated basalt fiber.

[0085] Step 2, weigh 0.1 g of calcium carbonate / PEI / PAMAM-2 prepared in Example 2, add it to 100 ml of acetone and disperse it evenly by ultrasonication, then add 0.5 g of E-51, mix evenly by ultrasonication to obtain a slurry for later use;

[0086] The acid-treated basalt fiber is immersed in the above slurry at room temperature for 20 seconds to obtain the modified basalt fiber.

[0087] Comparative Example 1

[0088] This comparative example provides a method for preparing modified basalt fiber, which is prepared specifically according to the following steps:

[0089] Step 1, placing the original basalt fiber into a beaker containing acetone, making the acetone cover the original basalt fiber, and soaking for 2 hours to remove impurities on the surface of the basalt fiber to obtain pretreated basalt fiber;

[0090] A hydrochloric acid solution with a concentration of 0.1 mol / L was prepared, and the pretreated basalt fiber was placed in the hydrochloric acid solution and soaked at 40°C for 30 minutes. After the treatment, the basalt fiber was washed with deionized water until the pH of the washing solution was 7, and then vacuum dried at 60°C to obtain the acid-treated basalt fiber.

[0091] The modified basalt fibers prepared in Examples 5-7 and Comparative Example 1 were added to concrete. The mix ratio of the C20 concrete used in the present invention is shown in Table 1. The components were weighed according to the mix ratio table. The cement was 42.5 grade cement. The length of the modified basalt fiber was 6 mm, and the fiber volume addition rate was 0.5%.

[0092] Table 1 Concrete mix ratio (kg / m 3 )

[0093] cement water sand Stone 461 175 512 1252

[0094] The concrete crack resistance test was carried out in accordance with the flat plate cracking test method in GB / T 50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete", as shown in Table 2.

[0095] Table 2 Test data of crack resistance board

[0096]

[0097] It can be seen from Table 2 that the addition of modified basalt fiber can effectively reduce the total crack area per unit area of ​​concrete. As the amount of calcium carbonate / PEI / PAMAM-2 added in the slurry increases, the crack resistance when the amount of calcium carbonate / PEI / PAMAM-2 added in the slurry is 0.15g is better than that when the amount of calcium carbonate / PEI / PAMAM-2 added in the slurry is 0.1g and 0.2g. The concrete mixed with modified basalt fiber prepared in Example 6 has two cracks, and the maximum crack width is 0.37mm.

[0098] The compressive strength test was conducted on the concrete mixed with the modified basalt fiber prepared in Example 6 and Comparative Example 1. The concrete cube compressive strength test used 100mm×100mm×100mm non-standard test blocks, 3 in each group. The cube compressive strength was measured in accordance with GB / T 50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete".

[0099] from Figure 1 It can be seen that the modified basalt fiber prepared by the preparation method of the present invention can effectively improve the compressive strength of concrete.

[0100] The present invention adds the modified basalt fiber to the concrete, thereby improving the meshing effect between the modified basalt fiber and the cement matrix and increasing the bonding strength. Meanwhile, the modified calcium carbonate is introduced into the basalt fiber to form a multi-scale structure. The calcium carbonate distributed on the fiber surface enables more CSH gel to be formed in the hydration product, thereby increasing the hydration degree of the cement, and is beneficial to increasing the compressive strength of the concrete and inhibiting the development of microcracks.

[0101] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0102] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing modified basalt fiber, characterized in that: Follow these steps to prepare: Step 1, preparation of calcium carbonate / PEI / PAMAM-2 Step 1.1, calcium carbonate is dispersed in water, polyethyleneimine is added, and reacted at 30-40°C to obtain calcium carbonate / PEI; the reaction time is 10-12h; the addition ratio of calcium carbonate, polyethyleneimine, and water is 30-50mg:70-100mg:100ml; Step 1.2, using calcium carbonate / PEI as raw materials, methyl acrylate and ethylenediamine as modifiers, reacting at 35-45°C, calcium carbonate / PEI / PAMAM-1; Step 1.2 Prepare according to the following steps: S1. Using methanol as solvent and methyl acrylate as modifier, calcium carbonate / PEI is added and reacted at 35-45°C to obtain calcium carbonate / PEI intermediate; the reaction time is 10-15h; the addition ratio of calcium carbonate / PEI, methyl acrylate and methanol is 30-50mg:20-30ml:400ml; S2. Using water as solvent and ethylenediamine as modifier, calcium carbonate / PEI-intermediate is added, and reacted at 35-45°C to obtain calcium carbonate / PEI / PAMAM-1; the reaction time is 10-15h; the addition ratio of calcium carbonate / PEI-intermediate, ethylenediamine and water is 30-50mg:25-35ml:400ml; Step 1.3, using calcium carbonate / PEI / PAMAM-1 as raw materials, repeating step 1.2 to prepare calcium carbonate / PEI / PAMAM-2; Step 2, mixing calcium carbonate / PEI / PAMAM-2, an organic compound and an organic solvent to obtain a slurry for standby use; Step 3: Preparation of modified basalt fiber Step 3.1, after removing impurities on the surface of the original basalt fiber, a pretreated basalt fiber is obtained, and the pretreated basalt fiber is immersed in a hydrochloric acid solution at 30-40° C. to obtain an acid-treated basalt fiber; Step 3.2: Immerse the acid-treated basalt fiber in the slurry at room temperature to obtain the modified basalt fiber.

2. The method for preparing modified basalt fiber according to claim 1, characterized in that: In step 2, the ratio of calcium carbonate / PEI / PAMAM-2, organic compound, and organic solvent is 0.1-0.2 g: 0.5 g: 100 ml.

3. The method for preparing modified basalt fiber according to claim 1, characterized in that: In step 2, the organic compound is bisphenol A epoxy resin, and the organic solvent is acetone or ethanol.

4. The method for preparing modified basalt fiber according to claim 1, characterized in that: In step 3.1, the original basalt fiber is soaked in acetone for 2-3 hours to remove impurities on the surface of the basalt fiber to obtain pretreated basalt fiber; Soak in a hydrochloric acid solution for 30-50 minutes. The concentration of the hydrochloric acid solution is 0.1 mol / L.

5. The method for preparing modified basalt fiber according to claim 1, characterized in that: In step 3.2, the soaking time is 15-20s.

6. A modified basalt fiber prepared by the method according to any one of claims 1 to 5.

7. Use of the modified basalt fiber according to claim 6 in the preparation of concrete materials.

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