Multi-dimensional mixed seepage pouring fiber concrete with controllable fiber mixing amount and preparation method of multi-dimensional mixed seepage pouring fiber concrete

Abstract

The invention relates to multi-dimensional hybrid infiltration fiber concrete with controllable fiber mixing amount, and belongs to the field of building material concrete. The high-strength concrete is prepared from the following components in parts by mass: 20 to 40 parts of quick-setting cement, 20 to 40 parts of fine aggregate, 5 to 10 parts of superfine silicon dioxide microbeads, 10 to 25 parts of waste tire steel fibers, 3 to 10 parts of three-dimensional spiral steel fibers, 0.2 to 0.4 part of a water reducing agent, 0.1 to 0.3 part of an interface exciting agent, 0.05 to 0.1 part of a thixotropic agent and 4 to 8 parts of water. The invention further provides a preparation method of the multi-dimensional mixed seepage pouring fiber concrete with the controllable fiber mixing amount. One-dimensional waste tire steel fibers and three-dimensional spiral steel fibers are mixed in a multi-dimensional mode, the mechanical property of the material is improved by optimizing the mixing amount and spatial distribution of the fibers, meanwhile, dependence on a special manufacturing mold or additional construction auxiliary control is not needed, the production cost and the construction difficulty are greatly reduced, and the composite material is more economical and suitable for engineering.

Description

Technical Field

[0001] The present invention belongs to the field of concrete, and particularly relates to a cast-in fiber concrete with a controllable fiber content based on waste tire steel fibers and three-dimensional spiral fibers and a preparation method thereof. Background Art

[0002] Cast-in fiber concrete is a steel fiber concrete formed by injecting mortar with a certain fluidity into a steel fiber skeleton mold placed in advance. The maximum volume fraction of its steel fibers can reach 25%. The mechanical properties of cast-in fiber concrete have been greatly improved compared with ordinary concrete. Its tensile strength can reach the same order of magnitude as the compressive strength of ordinary concrete, and the energy absorption capacity is 3 orders of magnitude larger than that of ordinary concrete.

[0003] Currently, the steel fibers used in cast-in concrete mainly include ordinary carbon steel fibers, stainless steel fibers, and relatively expensive copper-plated fine steel fibers. Among them, ordinary carbon steel fibers are widely used in general fiber-reinforced concrete due to their low cost, but their durability and corrosion resistance are weak; stainless steel fibers have good corrosion resistance and high strength, but their high price limits their application in large-scale projects; copper-plated fine steel fibers are usually used in ultra-high performance concrete (UHPC) or special structures. Since the copper-plated layer on their surface can enhance the bonding force between the fibers and the matrix, but the material cost is high, resulting in an increase in the overall project cost. However, due to the relatively fixed bulk density of steel fibers, it is difficult to flexibly adjust the dosage, resulting in the inability to precisely control the fiber distribution during the construction process. At the same time, a high dosage will not only reduce the permeability of the paste, affect the uniformity of the matrix, but also significantly increase the material cost, limiting the wide application of cast-in concrete in engineering.

[0004] With the continuous development of the automotive industry, a large amount of waste tires are generated every year. In the prior art, the treatment of these waste tires usually adopts simple methods such as open-air stacking or direct incineration. These methods not only occupy a large amount of land resources, but also cause serious environmental pollution and increase resource waste. How to efficiently recycle and rationally utilize the steel fibers in waste tires has become an important direction for promoting the development of green building materials. The steel fibers separated and screened from waste tires still have relatively high tensile strength. During the separation process, the fiber shape undergoes spatial distortion, improving its anchoring force and packing effect in the matrix. The rubber remaining on the fiber surface can further enhance the interfacial bonding force between the fiber and the matrix and improve the energy absorption capacity of the material. Based on this, the cast-in concrete prepared by the present invention using recycled waste tire steel fibers has both high cost performance and good construction adaptability, reducing the production cost while improving the comprehensive performance of the material.

[0005] To overcome the performance limitations of traditional steel fibers in cast-in-place concrete, some inventions adopt special three-dimensional fibers to optimize the spatial distribution of fibers. For example, Chinese Patent CN 113754332 A discloses a kind of three-dimensional steel fiber, and Chinese Patent CN 113636771 B discloses an arc-shaped steel fiber. Although these fibers can form a more stable reinforcement structure in concrete, their production depends on specific manufacturing molds, resulting in high manufacturing costs and complex processes, making it difficult to achieve large-scale engineering applications. In addition, Chinese Patent CN119462025A proposes a fiber spatial arrangement technology based on electromagnetic field directional control. Although this method can achieve the directional arrangement of fibers, its production process is cumbersome and the requirements for construction equipment are high, greatly increasing the difficulty and cost of project implementation. Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, the present invention provides a multi-dimensional hybrid cast-in-place fiber concrete with controllable fiber content and its preparation method. By regulating the total amount of steel fiber filling through the spatial characteristics of three-dimensional spiral steel fibers, and injecting high-strength and high-fluidity mortar with special preparation into the steel fiber skeleton mold placed in advance to prepare the cast-in-place fiber concrete, concrete with excellent mechanical properties and crack resistance can be prepared; the involved preparation method is simple and has low costs, can realize the utilization of waste tire steel fibers and the effective regulation of the total fiber amount, and has important economic, social and environmental benefits.

[0007] The technical solution adopted by the present invention to solve its technical problems is as follows: A multi-dimensional hybrid cast-in-place fiber concrete with controllable fiber content is composed of the following components in parts by mass: 20 parts - 40 parts of double-rapid cement, 20 parts - 40 parts of fine aggregate, 5 parts - 10 parts of ultra-fine silica microbeads, 10 parts - 25 parts of waste tire steel fibers, 3 parts - 10 parts of three-dimensional spiral steel fibers, 0.2 parts - 0.4 parts of water reducer, 0.1 parts - 0.3 parts of interfacial activator, 0.05 parts - 0.1 parts of thixotropic agent, and 4 parts - 8 parts of water.

[0008] Further, the double-rapid cement takes tricalcium silicate and calcium fluoroaluminate as the main raw materials, the setting time does not exceed 0.5 hours, and the strength is not less than 60 MPa.

[0009] Still further, the recycled fine aggregate is an aggregate with a particle size less than 0.6 mm and greater than 0.075 mm, and its material is silica.

[0010] Even further, the specific surface area of the ultra-fine silica microbeads is not less than 300 m2 / kg, and the particle size is distributed in the range of 0.2 - 2 μm.

[0011] The waste tire steel fiber is steel wire for rubber bead or tire edge wire, with a wire diameter of 0.2 mm to 2 mm, a length of 2 mm to 30 mm, and a tensile strength of not less than 1500 MPa.

[0012] The fiber raw wire diameter of the three-dimensional spiral steel fiber is 0.1 mm to 0.3 mm, the outer diameter of the spiral steel fiber is 4 mm to 20 mm, and the length is 5 mm to 40 mm.

[0013] The water reducing agent is a polycarboxylic acid type water reducing agent, and the water reducing rate is not less than 30%.

[0014] The interfacial activator is one or a mixture of two or more of ethanolamine, diethanolamine, triethanolamine, triisopropanolamine or diethanolmonoisopropanolamine.

[0015] The thixotropic agent is nano-silica, and its particle size is 30 nm to 50 nm.

[0016] A preparation method of multi-dimensional hybrid infiltrated fiber concrete with controllable fiber content, which uses multi-dimensional hybrid steel fiber as the main toughening material and is prepared by the infiltration method of high-strength and high-fluidity double-fast cement mortar. The method includes the following steps: Step 1: Mix the two kinds of fibers evenly and spread them over the entire mold. Utilize the spatial characteristics of the three-dimensional spiral steel fiber to form a three-dimensional space network structure of the above two kinds of fibers. The volume content of the hybrid fibers is controlled at 2% to 12%. Step 2: Prepare the infiltrated mortar according to the following ratio. For every cubic meter of mortar, calculated by 100 weight units, it consists of the following mass parts of components: 20 parts - 40 parts of double-fast cement, 20 parts - 40 parts of fine aggregate, 5 parts - 10 parts of ultra-fine silica fume, 10 parts - 25 parts of waste tire steel fiber, 3 parts - 10 parts of three-dimensional spiral steel fiber, 0.2 parts - 0.4 parts of water reducing agent, 0.1 parts - 0.3 parts of interfacial activator, 0.05 parts - 0.1 parts of thixotropic agent, and 4 parts - 8 parts of water. Step 3: Pour the double-fast cement, ultra-fine silica fume, water reducing agent, and thixotropic agent into a mixer according to the weight parts of the formula amount and dry-mix and stir evenly for 2 - 3 minutes. Then add the fine aggregate and interfacial activator and stir for 2 - 3 minutes. Then pour in the water and stir for 5 - 6 minutes to obtain the double-fast cement mortar paste. Step 4: Slowly pour the mortar paste obtained in Step 3 into the mold filled with hybrid fibers until the paste is slightly higher than the mold surface. Then place the mold in an environment with a temperature of 20 ± 5 °C and let it stand for one to two days. Then number it and remove the mold. Immediately after removing the mold, place it in a standard curing room with a temperature of 20 ± 2 °C and a relative humidity of more than 95% for curing for more than 28 days to obtain the infiltrated hybrid steel fiber concrete.

[0017] The technical concept of the present invention is as follows: multi-dimensional hybridization is carried out using one-dimensional waste tire steel fibers and three-dimensional spiral steel fibers. By optimizing the fiber dosage and spatial distribution, the mechanical properties of the material are improved. At the same time, the present invention does not rely on special manufacturing molds or additional construction auxiliary control, greatly reducing the production cost and construction difficulty, making it more economical and applicable to engineering.

[0018] Firstly, the present invention selects steel fibers extracted from waste tires, realizing the high-value recycling of waste materials. It not only effectively reduces environmental pollution but also improves the interfacial bonding between the fibers and the matrix by means of the rubber particles remaining on the surface of the waste tire steel fibers, thereby enhancing the overall mechanical properties of the concrete, with significant economic, environmental and social benefits. Secondly, the three-dimensional spiral steel fibers adopted in the present invention, due to their unique "spiral" spatial structure, form a mechanical interlocking effect with the cement matrix, significantly improving the interfacial bonding strength, delaying crack propagation, and enhancing the fracture toughness of the material. At the same time, the geometric shape of the three-dimensional spiral steel fibers is relatively complex, and its three-dimensional spiral structure has significant spatial advantages, enabling a high volume filling rate to be obtained with a very low fiber dosage. Most traditional cast-in-place fiber concretes use a single long straight fiber as the filling skeleton. Due to its constant packing density, the dosage of such fibers cannot be adjusted, and the small pores between the fibers often make it difficult to fill the slurry densely. To address the above problems, the present invention uses the spatial structure characteristics of three-dimensional spiral fibers to hybridize and fill with traditional long straight fibers, which can effectively control the volume dosage of long straight fibers, thereby obtaining a cast-in-place fiber concrete material with adjustable fiber dosage. Compared with traditional cast-in-place fiber concrete (SIFCON) which requires a fiber volume fraction of more than 10% to achieve good strengthening effects, the present invention, through a multi-dimensional hybridization strengthening strategy, can still ensure excellent tensile, impact and crack resistance properties at a lower dosage (≤ 4%), reducing the material usage and enhancing the economy. In addition, when preparing traditional cast-in-place steel fiber concrete, the steel fibers are often pre-placed in the mold in advance, and it is difficult to accurately calculate the volume dosage of the steel fibers. Affected by external vibration, problems such as the sinking of steel fibers and the difficulty of mortar infiltration are likely to occur. The cast-in-place fiber concrete adopted in the present invention has a cylindrical shape, which is convenient for calculating the filling volume. In addition, the hollow cavity inside the spiral fiber is conducive to the rapid filling of the cast-in-place mortar. Finally, the cast-in-place mortar of the present invention uses an interfacial activator and a thixotropic agent, which not only greatly improves the interfacial bonding force between the fibers and the slurry, increases the fiber pull-out energy consumption during failure, but also significantly enhances the rheology of the mortar and its void passing performance during pouring, thereby improving the density and construction convenience of the cast-in-place fiber concrete, enabling it to be widely used in rapid reinforcement and emergency repair projects, and demonstrating excellent compressive, flexural and shear properties as well as good ductility and toughness.

[0019] The present invention breaks through the limitations of traditional infiltrated fiber concrete by reasonably configuring one-dimensional and three-dimensional fibers, providing a new material solution with high strength, high toughness, and low cost for engineering.

[0020] The beneficial effects of the present invention are mainly manifested in: 1. The present invention adopts ultra-high fluidity rapid-hardening cement mortar, utilizes the spatial stability of three-dimensional spiral steel fibers, reduces fiber accumulation, enables the paste to penetrate the steel fiber skeleton more evenly and fully, improves the permeability and uniformity of the paste, and ensures the stable overall performance of the concrete.

[0021] 2. Compared with traditional infiltrated fiber concrete (SIFCON) which requires a high admixture content of more than 10% by volume, the multi-dimensional hybrid design of the present invention can still ensure good tensile, impact resistance, and crack resistance effects at a lower admixture content (≤ 4%).

[0022] 3. The present invention makes full use of recycled waste tire steel fibers, whose cost is much lower than that of copper-plated steel fibers or special three-dimensional steel fibers, and their twisted shape and rough surface contribute to improving the interfacial bonding force of the matrix. While maintaining excellent performance of the material, it has a higher cost performance and is suitable for large-scale engineering applications.

[0023] 4. The spatial bridging effect of the three-dimensional spiral steel fibers of the present invention can effectively disperse stress, inhibit crack propagation, and improve the energy absorption capacity of the concrete, and is applicable to scenarios with high toughness requirements such as bridges, tunnels, and seismic engineering. Description of the Drawings

[0024] Figure 1 is the direct tensile stress-strain curve of the multi-dimensional hybrid infiltrated fiber concrete of the present invention.

[0025] Figure 2 is the four-point bending load-displacement curve of the multi-dimensional hybrid infiltrated fiber concrete of the present invention. Detailed Embodiments

[0026] The present invention will be further described below.

[0027] Referring to Figure 1 and Figure 2 , a multi-dimensional hybrid infiltrated fiber concrete with controllable fiber content is composed of the following components in parts by mass: 20 parts - 40 parts of double-fast cement, 20 parts - 40 parts of fine aggregate, 5 parts - 10 parts of ultra-fine silica fume, 10 parts - 25 parts of recycled waste tire steel fibers, 3 parts - 10 parts of three-dimensional spiral steel fibers, 0.2 parts - 0.4 parts of water reducer, 0.1 parts - 0.3 parts of interfacial activator, 0.05 parts - 0.1 parts of thixotropic agent, and 4 parts - 8 parts of water.

[0028] Among them, the double - quick cement uses tricalcium silicate and calcium fluoroaluminate as the main raw materials, with a setting time of no more than 0.5 hours and a strength of no less than 60 MPa. The recycled fine aggregate is an aggregate with a particle size less than 0.6 mm and greater than 0.075 mm, and its material is silica. The specific surface area of the ultrafine silica microspheres is not less than 300 m2 / kg, and the particle size ranges from 0.2 to 2 μm. The waste tire steel fibers are steel wires for rubber tire beads or tire edge steel wires, with a wire diameter of 0.2 mm to 2 mm, a length of 2 mm to 30 mm, and a tensile strength of no less than 1500 MPa. The fiber filament diameter of the three - dimensional spiral steel fibers is 0.1 mm to 0.3 mm, the outer diameter of the spiral steel fibers is 4 mm to 20 mm, and the length is 5 mm to 40 mm. The water - reducing agent is a polycarboxylic acid - type water - reducing agent, with a water - reducing rate of no less than 30%. The interfacial activator is one or several of ethanolamine, diethanolamine, triethanolamine, triisopropanolamine, or diethanolmonoisopropanolamine. The thixotropic agent is nano - silica, with a particle size of 30 nm to 50 nm.

[0029] In the following embodiments, the double - quick cement used is high - belite sulphoaluminate cement; the fine aggregate used is 20 - mesh to 40 - mesh fine sand; the particle size range of the ultrafine silica microspheres used is between 50 μm and 100 μm; the water - reducing agent used is MELFLUX4930F polymer high - molecular water - reducing agent; the activator used is ultrafine slag powder; the thixotropic agent used is ATTGEL50 thixotropic agent.

[0030] Example 1 A multi - dimensional hybrid fiber concrete with controllable fiber content, the raw materials used in parts by mass include: 30 parts of double - quick cement, 30 parts of fine aggregate, 8 parts of ultrafine silica microspheres, 10 parts of waste tire steel fibers, 9 parts of three - dimensional spiral steel fibers, 0.3 part of water - reducing agent, 0.3 part of activator, 0.1 part of thixotropic agent, and 6 parts of water. The fiber volume content in this example is about 3.8%.

[0031] A preparation method of a multi - dimensional hybrid infiltrated fiber concrete with controllable fiber content, comprising the following steps: Step 1, mix the two kinds of fibers evenly and spread them over the entire mold, and use the spatial characteristics of the three - dimensional spiral steel fibers to make the above two kinds of fibers form a three - dimensional space network structure, and control the volume content of the hybrid fibers at 3.8%; According to the test or engineering requirements, place the mold in the pouring area and ensure good mold sealing. Evenly spread three-dimensional spiral steel fibers at the set dosage on the bottom of the formwork to form a network skeleton. Since the spiral steel fibers have self-supporting ability, a multi-dimensional support structure can be naturally formed after laying, providing a certain bearing capacity and avoiding excessive fiber accumulation or collapse. Above the skeleton of the three-dimensional spiral steel fibers, evenly spread the preset dosage of one-dimensional steel fibers. Due to the support provided by the three-dimensional spiral steel fibers, the one-dimensional steel fibers can be suspended, avoiding direct contact with the bottom of the formwork, thereby improving the uniformity of their spatial distribution in the matrix. Through slight shaking or low-speed air flow assistance, the one-dimensional steel fibers form a dispersed state under the support of the three-dimensional spiral steel fibers, improving the bridging effect between the fibers and avoiding local excessive accumulation;

[0032] Step two, prepare the grouting mortar according to the following ratio. For every cubic meter of mortar, based on 100 weight units, it consists of the following mass fractions of components: 30 parts of double-rapid cement, 30 parts of fine aggregate, 8 parts of ultra-fine silica microspheres, 10 parts of waste tire steel fibers, 9 parts of three-dimensional spiral steel fibers, 0.3 part of water reducer, 0.3 part of activator, 0.1 part of thixotropic agent, and 6 parts of water; Step three, according to the weight fractions of the formula, pour the double-rapid cement, ultra-fine silica microspheres, water reducer, and thixotropic agent into a mixer and dry-mix and stir evenly for 2 minutes, then add the fine aggregate and interfacial activator and stir for 2 minutes, and then pour in the water and stir for 5 minutes to obtain a double-rapid cement mortar slurry; The process of the said step three is as follows: S1. According to the weight fractions of the formula, pour the double-rapid cement, ultra-fine silica microspheres, water reducer, and thixotropic agent into a mixer and dry-mix and stir evenly. Stir at a speed of 40 r / min for not less than 2 minutes, then add the fine aggregate and interfacial activator and stir for 2 minutes to obtain a dry mixture; S2. Stir the dry mixture and water for 5 minutes to mix evenly to obtain a high-fluidity double-rapid cement mortar slurry.

[0033] Step four, slowly pour the mortar slurry obtained in step three into the mold filled with hybrid fibers until the slurry is slightly higher than the surface of the mold, then place the mold in an environment at 20°C and let it stand for one day and night, then number it and remove the mold; immediately after removing the mold, place it in a standard curing room at 20°C and a relative humidity of more than 95% for curing for more than 28 days to obtain the grouted hybrid steel fiber concrete.

[0034] Adopt the layered pouring method, slowly pour the ultra-high-fluidity cement mortar into the fiber space skeleton to ensure that the slurry fully wraps the fibers and avoid the slurry flow obstruction caused by fiber accumulation. Adopt low-frequency vibration to remove the air bubbles inside the slurry, improve the compactness of the concrete, and reduce the pores.

[0035] The curing process is as follows: S1. Demold after curing in a dry curing room at a temperature of 20°C for one day and night. S2. Transfer the test block to a standard curing room at a temperature of 20°C and a humidity of not less than 95% for curing for more than 28 days.

[0036] Then, conduct mechanical property measurement: Measure the tensile and flexural properties of the multi-dimensional hybrid cast-in-place fiber concrete at 28 days.

[0037] Example 2 A multi-dimensional hybrid fiber concrete with controllable fiber content, the raw materials used include, by mass parts: 30 parts of double-fast cement, 30 parts of fine aggregate, 8 parts of ultra-fine silica microspheres, 22 parts of waste tire steel fibers, 3 parts of three-dimensional spiral steel fibers, 0.3 part of water reducer, 0.3 part of activator, 0.1 part of thixotropic agent, and 6 parts of water. The fiber volume content in this example is about 8.2%.

[0038] A preparation method of a multi-dimensional hybrid cast-in-place fiber concrete with controllable fiber content includes the following steps: Step 1: Mix the two kinds of fibers evenly and spread them over the entire mold. Utilize the spatial characteristics of the three-dimensional spiral steel fibers to make the above two kinds of fibers form a three-dimensional space network structure, and control the volume content of the hybrid fibers at 8.2%. According to test or engineering requirements, place the mold in the pouring area and ensure good mold sealing. Spread the three-dimensional spiral steel fibers evenly at the bottom of the formwork according to the set content to form a network skeleton. Since the spiral steel fibers have self-supporting ability, they can naturally form a multi-dimensional support structure after laying, providing a certain bearing capacity and avoiding excessive fiber accumulation or collapse. Above the skeleton of the three-dimensional spiral steel fibers, evenly spread the preset amount of one-dimensional steel fibers. Due to the support provided by the three-dimensional spiral steel fibers, the one-dimensional steel fibers can be suspended, avoiding direct contact with the bottom of the formwork, thereby improving their spatial distribution uniformity in the matrix. Through slight shaking or low-speed air flow assistance, the one-dimensional steel fibers are in a dispersed state under the support of the three-dimensional spiral steel fibers, improving the bridging effect between fibers and avoiding local excessive accumulation;

[0039] Step 2: Prepare the cast-in-place mortar according to the following ratio. In each cubic meter of mortar, based on 100 weight units, it consists of the following mass parts of components: 30 parts of double-fast cement, 30 parts of fine aggregate, 8 parts of ultra-fine silica microspheres, 22 parts of waste tire steel fibers, 3 parts of three-dimensional spiral steel fibers, 0.3 part of water reducer, 0.3 part of activator, 0.1 part of thixotropic agent, and 6 parts of water.

[0040] In step 3 of this example, stir for 2.5 minutes, then add the fine aggregate and the interfacial activator and stir for 2.5 minutes, and then pour in the water and stir for 5.5 minutes to obtain the double-fast cement mortar slurry; In Step 4 of this embodiment, the mold is placed in an environment at a temperature of 15°C and left to stand for 1.5 days and nights, then numbered and demolded. After demolding, it is immediately placed in a standard curing room at a temperature of 15°C and a relative humidity of over 95% for curing for over 28 days.

[0041] The remaining steps are the same as those in Embodiment 1. Figure 1 and Figure 2 Table 1 shows the tensile and flexural test data of Embodiment 1 and Embodiment 2. Through the comparative analysis of the above two groups of embodiments, it can be seen that in Embodiment 1, although the content of three-dimensional spiral steel fibers is only slightly higher than that in Embodiment 2, and the content of one-dimensional fibers is significantly reduced, its overall mechanical properties do not show an obvious decline, and it can still maintain excellent ductility performance. This indicates that while optimizing the spatial distribution of fibers, three-dimensional spiral steel fibers can effectively control the fiber content, so that good mechanical properties can still be maintained when reducing the amount of one-dimensional fibers. This result further verifies the key role of three-dimensional spiral steel fibers in improving the fiber utilization efficiency and optimizing the material strengthening mechanism.

[0042] Embodiment 3 A multi-dimensional hybrid fiber concrete with controllable fiber content, the raw materials used are as follows by mass: 20 parts of double-rapid cement, 20 parts of fine aggregate, 5 parts of ultra-fine silica microbeads, 15 parts of waste tire steel fibers, 6 parts of three-dimensional spiral steel fibers, 0.2 parts of water reducer, 0.1 part of activator, 0.05 part of thixotropic agent and 4 parts of water. The fiber volume content in this example is about 5.9%.

[0043] Except for the different formula, the preparation method of this embodiment is the same as that of Embodiment 1.

[0044] In Step 3 of this embodiment, stir for 3 minutes, then add the fine aggregate and interfacial activator and stir for 3 minutes, and then pour water and stir for 6 minutes to obtain a double-rapid cement mortar paste; In Step 4 of this embodiment, the mold is placed in an environment at a temperature of 25°C and left to stand for two days and nights, then numbered and demolded. After demolding, it is immediately placed in a standard curing room at a temperature of 25°C and a relative humidity of over 95% for curing for over 28 days.

[0045] Embodiment 4 A multi-dimensional hybrid fiber concrete with controllable fiber content, the raw materials used are as follows by mass: 40 parts of double-rapid cement, 40 parts of fine aggregate, 10 parts of ultra-fine silica microbeads, 25 parts of waste tire steel fibers, 10 parts of three-dimensional spiral steel fibers, 0.4 parts of water reducer, 0.2 part of activator, 0.08 part of thixotropic agent and 8 parts of water. The fiber volume content in this example is about 4.8%.

[0046] Except for the different formula, the preparation method of this embodiment is the same as that of Embodiment 1.

[0047] In step three of this embodiment, stir for 3 minutes, then add fine aggregate and interfacial activator and stir for 2 minutes, and then pour water and stir for 6 minutes to obtain the double-fast cement mortar paste; In step four of this embodiment, place the mold in an environment at a temperature of 22°C and let it stand for two days and nights, then number it and remove the mold; immediately after removing the mold, place it in a standard curing room at a temperature of 24°C and a relative humidity of over 95% for curing for more than 28 days.

[0048] The content described in the embodiments of this specification is only a list of the implementation forms of the inventive concept and is only for illustrative purposes. The protection scope of the present invention should not be regarded as limited to the specific forms stated in this embodiment, and the protection scope of the present invention also extends to equivalent technical means that can be conceived by those of ordinary skill in the art based on the inventive concept of the present invention.

Claims

1. A multi-dimensional hybrid infiltration and casting fiber concrete with controllable fiber content, characterized in that, It consists of the following components in parts by mass: 20 - 40 parts of double - quick cement, 20 - 40 parts of fine aggregate, 5 - 10 parts of ultrafine silica microbeads, 10 - 25 parts of waste tire steel fibers, 3 - 10 parts of three - dimensional spiral steel fibers, 0.2 - 0.4 parts of water - reducing agent, 0.1 - 0.3 parts of interfacial activator, 0.05 - 0.1 parts of thixotropic agent, and 4 - 8 parts of water.

2. The multi-dimensional hybrid cast-in-place fiber concrete with controllable fiber content as claimed in claim 1, wherein The double - quick cement uses tricalcium silicate and calcium fluoroaluminate as the main raw materials, with a setting time of no more than 0.5 hours and a strength of no less than 60 MPa.

3. The multi-dimensional hybrid infiltrated fiber concrete with controllable fiber content according to claim 1 or 2, characterized in that, The recycled fine aggregate is an aggregate with a particle size less than 0.6 mm and greater than 0.075 mm, and its material is silica.

4. The multi-dimensional hybrid cast-in-place fiber concrete with controllable fiber content according to claim 1 or 2, characterized in that, The specific surface area of the ultrafine silica microbeads is not less than 300 m² / kg, and the particle size is distributed in the range of 0.2 - 2 μm.

5. The multi-dimensional hybrid cast-in-place fiber concrete with controllable fiber content as claimed in claim 1 or 2, wherein, The waste tire steel fibers are steel wires for rubber bead or tire edge wires, with a wire diameter of 0.2 mm to 2 mm, a length of 2 mm to 30 mm, and a tensile strength of no less than 1500 MPa.

6. The multi-dimensional hybrid infiltration fiber concrete with controllable fiber content as claimed in claim 1 or 2, characterized in that, The fiber filament diameter of the three - dimensional spiral steel fibers is 0.1 mm to 0.3 mm, the outer diameter of the spiral steel fibers is 4 mm to 20 mm, and the length is 5 mm to 40 mm.

7. The multi-dimensional hybrid cast-in-place fiber concrete with controllable fiber content as claimed in claim 1 or 2, characterized in that, The water - reducing agent is a polycarboxylic acid - type water - reducing agent, with a water - reducing rate of no less than 30%.

8. The multi-dimensional hybrid infiltration fiber concrete with controllable fiber content as claimed in claim 1 or 2, characterized in that, The interfacial activator is one or a mixture of two or more of ethanolamine, diethanolamine, triethanolamine, triisopropanolamine, or diethanolmonoisopropanolamine.

9. The multi-dimensional hybrid cast-in-place fiber concrete with controllable fiber content as claimed in claim 1 or 2, characterized in that, The thixotropic agent is nano - silica, with a particle size of 30 nm to 50 nm.

10. A method for preparing a multi-dimensional hybrid infiltrated fiber concrete with controllable fiber content as described in claim 1, characterized in that, The method includes the following steps: Step 1: Mix the two types of fibers evenly and spread them over the entire mold. Utilize the spatial characteristics of the three - dimensional spiral steel fibers to form a three - dimensional space network structure of the above - mentioned two types of fibers. The volume fraction of the hybrid fibers is controlled at 2% to 12%. Step 2: Prepare the grout for infiltration pouring according to the following ratio. For every cubic meter of mortar, calculated in 100 weight units, it consists of the following components in parts by mass: 20 - 40 parts of double - quick cement, 20 - 40 parts of fine aggregate, 5 - 10 parts of ultrafine silica microbeads, 10 - 25 parts of waste tire steel fibers, 3 - 10 parts of three - dimensional spiral steel fibers, 0.2 - 0.4 parts of water - reducing agent, 0.1 - 0.3 parts of interfacial activator, 0.05 - 0.1 parts of thixotropic agent, and 4 - 8 parts of water. Step 3: Pour the double - quick cement, ultrafine silica microbeads, water - reducing agent, and thixotropic agent into a mixer according to the weight parts of the formula and dry - mix and stir evenly for 2 - 3 minutes. Then add the fine aggregate and interfacial activator and stir for 2 - 3 minutes. Then pour in the water and stir for 5 - 6 minutes to obtain the double - quick cement mortar slurry. Step 4: Slowly pour the mortar slurry obtained in Step 3 into the mold filled with hybrid fibers until the slurry is slightly higher than the mold surface. Then place the mold in an environment with a temperature of 20 ± 5°C and let it stand for one to two days. Then number it and remove the mold. Immediately after removing the mold, place it in a standard curing room with a temperature of 20 ± 2°C and a relative humidity of more than 95% for curing for more than 28 days to obtain the infiltrated hybrid steel fiber concrete.

Images