High-strength, crack-resistant concrete precast member and method of making same

Abstract

This application relates to the field of precast concrete components, specifically disclosing a high-strength, crack-resistant precast concrete component and its preparation method. The high-strength, crack-resistant precast concrete component comprises the following components in parts by weight: 0.3-0.6 parts reinforcing fiber; 1-3 parts kiwifruit vine extract; 25-42 parts cementitious material; 98-123 parts coarse aggregate; 52-78 parts fine aggregate; 11-16 parts water; 3.2-5.6 parts water glass; 0.5-0.9 parts sodium fluorosilicate; and 1-2 parts admixture. The reinforcing fiber is obtained by grafting and modifying methyl methacrylate as a monomer. The kiwifruit vine extract is obtained from kiwifruit vine through crushing, water extraction, and ethanol extraction. The addition of kiwifruit vine extract to the components of this high-strength, crack-resistant precast concrete component improves the strength and crack resistance of the precast component.

Description

Technical Field

[0001] This application relates to the field of precast concrete components, and more specifically, to a high-strength, crack-resistant precast concrete component and a method for preparing the same. Background Technology

[0002] Precast concrete components are assembled building parts made in a factory using concrete as the basic material. The manufacturing process of precast concrete components can be carried out steadily according to a stable process route, so its quality control, especially crack control performance, is better than that of cast-in-place concrete structures. However, some cracks often occur in concrete production, affecting its quality performance.

[0003] To improve the crack resistance of concrete, a type of crack-resistant precast concrete component has been developed, which includes cement, crushed stone, sand, water, water-reducing agent, water glass, sodium fluorosilicate, and polypropylene fiber. The addition of polypropylene fiber enhances the crack resistance of the precast component, resulting in a strength of 70 MPa and no early cracking.

[0004] With the continuous promotion of precast concrete technology and prefabricated concrete systems in recent years, the requirements for modern precast concrete components are more focused on high strength and durability. The most common way to improve the strength of precast components is to reduce the water-cement ratio. However, most of the water required for hydration comes from capillary water. When the capillary water seepage rate is less than the hydration rate, the capillaries tend to change from a water-saturated state to an unsaturated state, causing the precast components to have greater self-shrinkage and reduce crack resistance. Summary of the Invention

[0005] In order to simultaneously improve the strength and crack resistance of precast concrete components, this application provides a high-strength, crack-resistant precast concrete component and its preparation method.

[0006] This application provides a high-strength, crack-resistant precast concrete component and its preparation method, employing the following technical solution: Firstly, this application provides a high-strength, crack-resistant precast concrete component, employing the following technical solution: A high-strength, crack-resistant precast concrete component comprises the following components in parts by weight: Reinforcing fiber 0.3-0.6 parts; Kiwi vine extract 1-3 parts; 25-42 parts cementitious material; 98-123 parts coarse aggregate; 52-78 parts fine aggregate; 11-16 parts water; 3.2-5.6 parts water glass; 0.5-0.9 parts sodium fluorosilicate; 1-2 parts admixture; The reinforcing fiber was obtained by grafting and modifying methyl methacrylate as a monomer; The kiwi vine extract is obtained by crushing, water extraction, and ethanol extraction of kiwi vines.

[0007] By adopting the above technical solution, the strength of precast components is increased by reducing the water-cement ratio. Concrete cracks stop upon contact with the fibers, thus increasing fiber strength can further reduce crack formation. Therefore, grafting methyl methacrylate onto the fibers alters the molecular polarity, thereby increasing fiber strength and delaying crack initiation. Adding kiwi vine extract has the following advantages: 1) The plant gums it contains hydrate to form a glue, which reduces direct water loss, reduces the drying shrinkage of precast parts caused by excessive drying speed, and reduces the occurrence of cracks. 2) The viscosity of the hydrated adhesive decreases with the increase of shear rate. During blending, it improves the workability of the preform base material and balances the effect of the water-cement ratio. After static curing, it improves the bonding strength between the modified fiber and the preform base material, and between the components of the preform, thereby improving the crack resistance of the preform. 3) It has the ability to disperse fibers, promoting the uniform dispersion of fibers in cementitious materials, thereby improving the enhancement effect of modified fibers on the performance of precast components and further delaying the occurrence of cracks.

[0008] The performance of each precast component was tested and found to be as follows: when only polypropylene fiber was used, the compressive strength was 71.2 MPa and the cracking time was 153 h; when only kiwi vine extract was used, the compressive strength was 75.7 MPa and the cracking time was 223 h; when only reinforcing fiber was used, the compressive strength was 73.5 MPa and the cracking time was 179 h; and when both reinforcing fiber and kiwi vine extract were added, the compressive strength reached a maximum of 81.5 MPa and the cracking time was extended to 276 h, thus proving the above findings.

[0009] Optional components may include the following parts by weight: 0.4-0.5 parts of reinforcing fiber; Kiwi vine extract 1.5-2.5 parts; 30-38 parts cementitious material; 105-114 parts coarse aggregate; 60-70 parts fine aggregate; 12-14 parts water; 3.8-5.0 parts water glass; 0.6-0.8 parts sodium fluorosilicate; 1.2-1.7 parts admixture.

[0010] By adopting the above technical solution, when the weight of each component of the precast component is within the above range, the precast component has higher strength and better crack resistance.

[0011] Optionally, the ethanol used in the preparation of the kiwi vine extract has a concentration of 80-90 wt%.

[0012] By adopting the above technical solution, when the concentration of ethanol is within the above range, the extraction rate and purity of kiwi vine extract are higher, which is conducive to the industrial-scale preparation of kiwi vine extract.

[0013] Optionally, the method for preparing the reinforcing fiber is as follows: adding methyl methacrylate and a photoinitiator to a solvent, stirring and mixing to obtain a grafting solution; adding the fiber to the grafting solution, stirring and mixing, impregnating, filtering to remove the filtrate, irradiating with UV light, washing, and drying to obtain the fiber; The weight ratio of the solvent, methyl methacrylate, and photoinitiator is (1.5-2):1:(0.3-0.5).

[0014] By adopting the above technical solution, when the weight ratio of solvent, methyl methacrylate, and photoinitiator is within the above range, the resulting reinforcing fiber has higher strength and better reinforcement and crack resistance for the preform.

[0015] Optionally, the photoinitiator is a mixture of photoinitiator TPO and photoinitiator 907.

[0016] By adopting the above technical solution, the primary free radicals generated by photoinitiator 907 molecules after ultraviolet light excitation have small steric hindrance, making them easy to collide with monomers, resulting in a short photopolymerization reaction time and improved photopolymerization efficiency.

[0017] Optionally, the photoinitiator TPO and photoinitiator 907 are used in a weight ratio of 1:(1.1-1.5).

[0018] Optionally, the fiber length is 9-15 mm.

[0019] Secondly, this application provides a method for preparing high-strength, crack-resistant precast concrete components, employing the following technical solution: A method for preparing high-strength, crack-resistant precast concrete components includes the following steps: S1. Add coarse aggregate, fine aggregate, water and admixture to the cementitious material, stir and mix to obtain a mixture; S2. Add reinforcing fiber, kiwi vine extract, sodium fluorosilicate, and water glass to the mixture, stir and mix, pour into a mold, steam cure, heat to 55-60℃, keep at a constant temperature for 5-8 hours, cool down, let stand to cure, demold, and the product is obtained.

[0020] By adopting the above technical solution, the process is simple, the preparation steps are few, and the manufactured parts and preforms have both high strength and good crack resistance.

[0021] Thirdly, this application provides a high-strength, crack-resistant precast concrete component, which adopts the following technical solution: a high-strength, crack-resistant precast concrete component, comprising the components of the above-mentioned precast component, the components also including borax, and the weight ratio of the amount of borax added to the kiwi vine extract is (0.2-0.25):1.

[0022] By adopting the above technical solution, borax and the plant gum in kiwi vine extract can undergo a cross-linking reaction, thereby forming a layer of adhesive with a higher viscosity than the plant gum between the reinforcing fiber and the precast base material. This improves the bonding strength between the two, making it less likely for the reinforcing fiber to detach from the precast base material when cracks occur. The adhesive layer also fills the gaps between the components, reducing the porosity of the precast, which not only further improves the strength but also enhances the impermeability and delays the cracking of the precast caused by prolonged water immersion. Performance tests were conducted on each precast component. Without borax, the compressive strength was 81.4 MPa and the cracking time was 275 h. With the addition of borax, the compressive strength reached 84.4-84.9 MPa and the cracking time was as long as 292-298 h, thus producing a high-strength concrete precast component with better crack resistance.

[0023] Since borax dissolved in water has a retarding effect on concrete, reducing the amount of borax added within the above range not only improves the performance of the precast components but also does not significantly affect the setting time of the precast components.

[0024] Fourthly, this application provides a method for preparing high-strength, crack-resistant precast concrete components, employing the following technical solution: A method for preparing high-strength, crack-resistant precast concrete components includes the following steps: S1. Add coarse aggregate, fine aggregate, water and admixture to the cementitious material, stir and mix to obtain a mixture; S2. Add reinforcing fiber, kiwi vine extract, borax, sodium fluorosilicate, and water glass to the mixture, stir and mix, pour into a mold, steam cure, heat to 55-60℃, keep at a constant temperature for 5-8 hours, cool down, let stand to cure, demold, and the product is obtained.

[0025] By adopting the above technical solution, borax is added after cement hydration, which reduces the influence of borax on the setting time of concrete, and the resulting precast components have high strength and superior crack resistance.

[0026] In summary, this application has the following beneficial effects: 1. This application improves the strength of precast components by adding high-strength reinforcing fibers; by adding kiwi vine extract, the reinforcing fibers are evenly dispersed in the concrete matrix, improving the effect of the reinforcing fibers. At the same time, the hydration products of kiwi vine extract adsorb moisture, reducing shrinkage caused by excessive moisture loss during concrete drying, fundamentally reducing crack formation. Furthermore, the hydration products improve the bond strength between the fibers and the concrete matrix, further enhancing the effect of the reinforcing fibers. 2. In the preparation process of kiwifruit vine extract, this application promotes precipitation of kiwifruit vine extract and improves the extraction rate by controlling the ethanol concentration; 3. In this application, by adding a small amount of borax, it undergoes a cross-linking reaction with the plant gum in the kiwi vine extract to form a glue layer with a certain viscosity, thereby improving the bonding strength between the reinforcing fiber and the concrete matrix, allowing the reinforcing fiber to exert its optimal effect, and improving the strength and crack resistance of the precast component. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the embodiments.

[0028] Preparation Example Preparation Example 1 A kiwi vine extract, the preparation method of which is as follows: Wash 10 kg of kiwi vines with water and crush them into 2-3 cm diameter segments. Add them to 10 kg of water and stir for 3 hours while continuously crushing the kiwi vines. Filter to remove the residue, add 75% ethanol aqueous solution and extract for 3 hours, stirring once every 0.5 hours. Filter to remove the filtrate, spray dry, crush, and pass through a 100-mesh sieve to obtain the final product.

[0029] Preparation Examples 2-4 A kiwi vine extract, differing from Preparation Example 1 in that the concentration of the ethanol aqueous solution is as follows: Preparation Example 1: The concentration of the ethanol aqueous solution was 75%.

[0030] Preparation Example 2: The concentration of the ethanol aqueous solution is 80%.

[0031] Preparation Example 3: The concentration of the ethanol aqueous solution was 85%.

[0032] Preparation Example 4: The concentration of the ethanol aqueous solution was 90%.

[0033] Preparation Example 5 A reinforcing fiber is prepared by the following steps: Add 10 kg of methyl methacrylate and 2.5 kg of photoinitiator (TPO) to 14 kg of solvent (anhydrous ethanol), stir and mix to obtain a grafting solution; add 2 kg of fiber (polypropylene fiber, 18 mm in length) to 26.5 kg of grafting solution, stir and mix, impregnate for 30 min, filter to remove the filtrate, and irradiate with UV light (wavelength 365 nm, irradiance 0.8 W / m²). 2 After 4 minutes, wash with deionized water and dry at 35°C for 1 hour to obtain the product.

[0034] Preparation Examples 6-8 A reinforcing fiber differs from that in Preparation Example 5 in that the amounts of each component of the grafting solution used are different. The weight proportions of anhydrous ethanol, methyl methacrylate, and photoinitiator are as follows: Preparation Example 5: The weight ratio of anhydrous ethanol, methyl methacrylate, and photoinitiator was 1.4:1:0.25.

[0035] Preparation Example 6: The weight ratio of anhydrous ethanol, methyl methacrylate, and photoinitiator was 1.5:1:0.3.

[0036] Preparation Example 7: The weight ratio of anhydrous ethanol, methyl methacrylate, and photoinitiator was 1.7:1:0.4.

[0037] Preparation Example 8: The weight ratio of anhydrous ethanol, methyl methacrylate, and photoinitiator was 2:1:0.5.

[0038] Preparation Examples 9-12 A reinforcing fiber differs from Preparation Example 5 in the use of the photoinitiator, as follows: Preparation Example 9: A mixture of equal amounts of photoinitiator TPO and photoinitiator 907 in a weight ratio of 1:1 was used to replace photoinitiator TPO.

[0039] Preparation Example 10: A mixture of equal amounts of photoinitiator TPO and photoinitiator 907 in a weight ratio of 1:1.1 was used to replace photoinitiator TPO.

[0040] Preparation Example 11: A mixture of equal amounts of photoinitiator TPO and photoinitiator 907 in a weight ratio of 1:1.3 was used to replace photoinitiator TPO.

[0041] Preparation Example 12: A mixture of equal amounts of photoinitiator TPO and photoinitiator 907 in a weight ratio of 1:1.5 was used to replace photoinitiator TPO.

[0042] Preparation Examples 13-15 A reinforcing fiber, differing from preparation example 5, has the following fiber length: Preparation Example 5: Fiber length is 18 mm.

[0043] Preparation Example 13: Fiber length is 15 mm.

[0044] Preparation Example 14: Fiber length is 12 mm.

[0045] Preparation Example 15: Fiber length is 9 mm. Example

[0046] Examples 1-7, Comparative Examples 1-2 A high-strength, crack-resistant precast concrete component, the components and their corresponding weights are shown in Table 1, and it is prepared by the following steps: S1. Add coarse aggregate (crushed stone, particle size 5-10mm), fine aggregate (manufactured sand, fineness modulus 2.4-2.8), water and admixture (polycarboxylate superplasticizer, water reduction rate 40%) to the cementitious material (silicate cement, P.Ⅱ52.5R), stir until well mixed, and obtain a mixture. S2. Add reinforcing fiber (prepared in Preparation Example 5), kiwi vine extract (prepared in Preparation Example 1), sodium fluorosilicate (purity 98%), and water glass (silicic acid water glass) to the mixture, stir until well mixed, pour into a mold, steam cure for 60 min, heat to 55°C, keep at the temperature for 5 h, cool to 25°C, and then place in a standard curing room for standard curing for 28 days. Demold to obtain the product. The water glass was sourced from Jinan Xinyuancheng Chemical Technology Co., Ltd.

[0047] Table 1. Components and their weights (kg) in Examples 1-7 and Comparative Examples 1-2 Comparative Example 3 A precast concrete component differs from Example 1 in that it uses an equal amount of polypropylene fiber instead of reinforcing fiber and kiwi vine extract.

[0048] Comparative Example 4 A precast concrete component differs from Example 1 in that it uses an equal amount of polypropylene fibers instead of reinforcing fibers.

[0049] Comparative Example 5 A precast concrete component differs from Example 1 in that it does not contain kiwi vine extract, while the total weight of all components of the precast component remains unchanged.

[0050] Examples 8-11 A high-strength, crack-resistant precast concrete component differs from Example 1 in the use of kiwi vine extract, as detailed below: Example 1: Kiwi vine extract was prepared from Preparation Example 1.

[0051] Example 8: Kiwi vine extract was prepared from Preparation Example 2.

[0052] Example 9: Kiwi vine extract was prepared from Preparation Example 3.

[0053] Example 10: Kiwi vine extract was prepared from Preparation Example 4.

[0054] Examples 11-20 A high-strength, crack-resistant precast concrete component differs from Example 1 in the use of reinforcing fibers, as detailed below.

[0055] Example 1: The reinforcing fiber was prepared from Preparation Example 5.

[0056] Example 11: The reinforcing fiber was prepared from Preparation Example 6.

[0057] Example 12: The reinforcing fiber was prepared from Preparation Example 7.

[0058] Example 13: The reinforcing fiber was prepared from Preparation Example 8.

[0059] Example 14: The reinforcing fiber was prepared from Preparation Example 9.

[0060] Example 15: The reinforcing fiber was prepared from Preparation Example 10.

[0061] Example 16: The reinforcing fiber was prepared from Preparation Example 11.

[0062] Example 17: The reinforcing fiber was prepared from Preparation Example 12.

[0063] Example 18: The reinforcing fiber was prepared from Preparation Example 13.

[0064] Example 19: The reinforcing fiber was prepared from Preparation Example 14.

[0065] Example 20: The reinforcing fiber was prepared from Preparation Example 15.

[0066] Example 21 A high-strength, crack-resistant precast concrete component is prepared through the following steps: S1. Add 109 kg of coarse aggregate (crushed stone, particle size 5-10 mm), 65 kg of fine aggregate (manufactured sand, fineness modulus 2.4-2.8), 13 kg of water and 1.5 kg of admixture (polycarboxylate superplasticizer, water reduction rate 40%) to 34 kg of cementitious material (Silicate cement, P.Ⅱ52.5R), stir until well mixed, and obtain a mixture. S2. Add 0.45 kg of reinforcing fiber (prepared in Preparation Example 1), 2 kg of kiwi vine extract (prepared in Preparation Example 12), 0.4 kg of borax, 0.7 kg of sodium fluorosilicate (98% purity), and 4.4 kg of water glass (silicic acid water glass) to the mixture, stir until well mixed, pour into a mold, steam cure for 60 min, heat to 55°C, keep at the temperature for 5 h, cool to 25°C, and then place in a standard curing room for standard curing for 28 days. Demold to obtain the product. The water glass was sourced from Jinan Xinyuancheng Chemical Technology Co., Ltd.

[0067] Examples 22-23 A high-strength, crack-resistant precast concrete component differs from Example 4 in the amount of borax added, as follows: Example 21, the weight ratio of borax added to kiwi vine extract is 0.2:1.

[0068] Example 22: The weight ratio of borax added to kiwi vine extract was 0.22:1.

[0069] Example 23: The weight ratio of borax added to kiwi vine extract was 0.25:1.

[0070] It should be noted that in step S2 of the preparation of precast concrete components, the temperature after heating can be selected within the range of 55-60°C, specifically 55°C, 58°C, and 60°C; similarly, the holding time can be selected within the range of 5-8 hours, specifically 5h, 6h, 7h, and 8h. The above selection does not have a significant impact on the test results. In this embodiment, only 55°C and 5h are briefly described as examples.

[0071] Performance testing The precast concrete components produced in the examples and comparative examples were subjected to the following performance tests, and the test results are recorded in Table 2.

[0072] Detection methods 1. Compressive strength: Tested according to GB / T 50081-2019.

[0073] 2. Crack Resistance: The crack resistance performance of concrete was tested using the circular ring method and a crack resistance mold. The crack resistance mold consisted of a base, side molds, a core mold, and a top cover. The core mold was made of steel, while the other components were made of plexiglass. The specimen formed using the crack resistance mold had an outer diameter of 370 mm, an inner diameter of 300 mm, and a height of 140 mm. The specific testing method is as follows: 1) Open the top cover of the crack-resistant test mold, stir the material in step S2 of the preform preparation of this application until it is well mixed, and use a small shovel to put it into the crack-resistant test mold in two layers. The thickness of each layer should be approximately equal. Use a tamping rod to tamp the material evenly. The number of tamping times is 15 times per 10,000 square centimeters. When tamping the bottom layer, the tamping rod should reach the bottom of the test mold. When tamping the top layer, the tamping rod should penetrate the top layer and then insert into the bottom layer by 20-30mm. The tamping rod should be vertical and not tilted when tamping. 2) After curing the molded crack-resistant specimen in an environment at 20℃ for 24 hours, remove the mold. Immediately after removing the mold, place the crack-resistant specimen in an environment at 30℃ and relative humidity of (50±5)%, and seal the top surface of the specimen with silicone. 3) Use a strain gauge or magnifying glass to observe and record the time when the first through crack appears on the ring surface. Record this as the cracking time. The longer the time, the better the crack resistance of the precast concrete.

[0074] Table 2 Performance Test Results Referring to Table 2, in Example 1, the use of kiwi vine extract prepared in Preparation Example 1 and reinforcing fiber prepared in Preparation Example 5 resulted in a preform with a compressive strength of 80.5 MPa and a cracking time of 266 h. In contrast, in Comparative Example 3, polypropylene fiber was used to replace both reinforcing fiber and kiwi vine extract, resulting in a preform with a compressive strength of 71.2 MPa and a cracking time of 153 h. These data indicate that adding reinforcing fiber and kiwi vine extract can improve the strength and crack resistance of the preform.

[0075] The reasons for this may be as follows: reducing the water-cement ratio increases the strength of the precast component, but reduces its crack resistance. Therefore, this application uses reinforcing fibers with higher strength, making the crack resistance of the precast component better than that of precast components with added polypropylene fibers. At the same time, kiwi vine extract is added, and its hydrate not only improves the workability of the components when blending, but also enhances the bond strength between the reinforcing fibers and the precast component matrix, delaying the occurrence of cracks. In addition, kiwi vine extract absorbs water through hydration, directly delaying the direct loss of water and reducing the drying shrinkage caused by excessive water loss, thus reducing the occurrence of cracks from the root.

[0076] Furthermore, in Comparative Example 4, polypropylene fibers were used instead of reinforcing fibers. The compressive strength of the preform was 75.7 MPa, and the cracking time was 223 h, which was higher than that of Comparative Example 3. This indicates that using only kiwi vine extract can also improve the performance of the preform. The reason may be that the fibers have better dispersibility and the bonding strength of the components of the preform is higher, but there is still room for further improvement in various properties. In contrast, in Comparative Example 5, no kiwi vine extract was added. The compressive strength of the preform was 73.5 MPa, and the cracking time was 179 h, which was higher than that of Comparative Example 3. This indicates that using only reinforcing fibers can improve the strength and crack resistance, but the improvement effect is insufficient. This demonstrates that the present application uses both reinforcing fibers and kiwi vine extract to prepare a high-strength, crack-resistant precast concrete component.

[0077] The difference between Examples 1-7 and Comparative Examples 1-2 lies in the different amounts of each component used in the preform. As shown in Table 2, when the amounts of each component used in the preform are within the range of Examples 1-7, the strength and crack resistance of the preform are better. The difference between Examples 3-5 lies in the different amounts of kiwifruit vine extract used. When the amount used is increased from Example 3 to Example 4, the strength and crack resistance of the preform are significantly improved. However, when the amount is further increased to Example 5, the improvement in performance becomes less obvious. Considering other factors such as cost, it indicates that the amount of kiwifruit vine extract used should be within a certain range, and Example 4 is the optimal example.

[0078] The difference between Examples 20-23 and Example 4 is that borax was added during the preparation of the preform. In Examples 20-23, the compressive strength reached 84.4-84.9 MPa, and the cracking time was extended to 292-298 h, showing a significant improvement compared to Example 5. This may be because the cross-linking of borax with kiwi vine extract forms a more viscous adhesive layer, which not only improves the bonding strength between the reinforcing fibers and the components, hindering the formation of cracks in the preform, but also fills the internal pores of the preform, improving its strength, crack resistance, and impermeability.

[0079] It should be noted that borax has a retarding effect on concrete, but the amount of borax added in this application is relatively small, and it needs to be cross-linked with kiwi vine extract to reduce the amount of complex formed with calcium ions in the precast components. Therefore, it does not produce a significant retarding effect.

[0080] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high-strength, crack-resistant precast concrete component, characterized in that, The components include the following parts by weight: Reinforcing fiber 0.3-0.6 parts; Kiwi vine extract 1-3 parts; 25-42 parts cementitious material; 98-123 parts coarse aggregate; 52-78 parts fine aggregate; 11-16 parts water; 3.2-5.6 parts water glass; 0.5-0.9 parts sodium fluorosilicate; 1-2 parts admixture; The reinforcing fiber was obtained by grafting and modifying methyl methacrylate as a monomer; The kiwi vine extract is obtained by crushing, water extraction and ethanol extraction of kiwi vine as raw material; The method for preparing the reinforcing fiber is as follows: methyl methacrylate and photoinitiator are added to a solvent and stirred to obtain a grafting solution; the fiber is added to the grafting solution, stirred to obtain a grafting solution, impregnated, filtered to remove the filtrate, irradiated with UV light, washed, and dried to obtain the fiber. The weight ratio of the solvent, methyl methacrylate, and photoinitiator is (1.5-2):1:(0.3-0.5).

2. The high-strength, crack-resistant precast concrete component according to claim 1, characterized in that: The components include the following parts by weight: 0.4-0.5 parts of reinforcing fiber; Kiwi vine extract 1.5-2.5 parts; 30-38 parts cementitious material; 105-114 parts coarse aggregate; 60-70 parts fine aggregate; 12-14 parts water; 3.8-5.0 parts water glass; 0.6-0.8 parts sodium fluorosilicate; 1.2-1.7 parts admixture.

3. A high-strength, crack-resistant precast concrete component according to claim 1 or 2, characterized in that: The ethanol used in the preparation of the kiwi vine extract has a concentration of 80-90 wt%.

4. A high-strength, crack-resistant precast concrete component according to claim 1, characterized in that: The photoinitiator is a mixture of photoinitiator TPO and photoinitiator 907.

5. A high-strength, crack-resistant precast concrete component according to claim 4, characterized in that: The photoinitiator TPO and photoinitiator 907 are in a weight ratio of 1:(1.1-1.5).

6. A high-strength, crack-resistant precast concrete component according to claim 3, characterized in that: The fiber length is 9-15 mm.

7. A high-strength, crack-resistant precast concrete component according to claim 1, characterized in that: The components also include borax, with the weight ratio of borax to kiwi vine extract being (0.2-0.25):

1.

8. A method for preparing a high-strength, crack-resistant precast concrete component according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Add coarse aggregate, fine aggregate, water and admixture to the cementitious material, stir and mix to obtain a mixture; S2. Add reinforcing fiber, kiwi vine extract, sodium fluorosilicate, and water glass to the mixture, stir and mix, pour into a mold, steam cure, heat to 55-60℃, keep at a constant temperature for 5-8 hours, cool down, let stand to cure, demold, and the product is obtained.

9. A method for preparing a high-strength, crack-resistant precast concrete component as described in claim 7, characterized in that, Includes the following steps: S1. Add coarse aggregate, fine aggregate, water and admixture to the cementitious material, stir and mix to obtain a mixture; S2. Add reinforcing fiber, kiwi vine extract, borax, sodium fluorosilicate, and water glass to the mixture, stir and mix, pour into a mold, steam cure, heat to 55-60℃, keep at a constant temperature for 5-8 hours, cool down, let stand to cure, demold, and the product is obtained.

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