Preparation method and product of high-strength concrete based on expandable fibers

Abstract

A method for preparing high-strength concrete based on expandable fibers includes first uniformly mixing expandable graphite particles with a polymer spinning solution to obtain a mixed solution. The mixed solution is then subjected to electrospinning, wet spinning, air-jet spinning, or centrifugal spinning to produce spun fibers, i.e., expandable fibers. The expandable fibers are then uniformly mixed with concrete raw materials, and water is added and stirred to obtain a concrete slurry. The concrete slurry is then allowed to solidify to obtain a solidified body. The solidified body is then heated at a temperature of 200°C to 600°C. When the expandable graphite in the solidified body expands due to the heat, the high-strength concrete is obtained. This design not only improves interfacial properties and reduces production costs, but also enhances the mechanical strength of the final product.

Description

Technical Field

[0001] The present invention relates to a preparation process of high-strength concrete, belongs to the field of concrete, and in particular to a preparation method and product of high-strength concrete based on expandable fibers. Background Art

[0002] Concrete, as an inorganic non-metallic silicate material, is widely used in the construction field. In the existing technology, in order to improve the mechanical strength of concrete, external fiber materials are often added to concrete. This is also a common method. However, this method of directly mixing ordinary fiber materials into concrete has the following shortcomings:

[0003] In the resulting fiber / concrete composite material, gaps will exist between the fibers and concrete, resulting in poor interfacial properties between the fibers and concrete, thereby reducing the overall mechanical properties, such as strength.

[0004] The information disclosed in this background technology section is only intended to increase understanding of the overall background of the application and should not be considered as an admission or any form of suggestion that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects and problems of poor interface performance in the prior art and to provide a method and product for preparing high-strength concrete based on expandable fibers with better interface performance.

[0006] To achieve the above objectives, the technical solution of the present invention is: a method for preparing high-strength concrete based on expandable fibers, the preparation method comprising the following steps:

[0007] The first step is to uniformly mix expandable graphite particles with a polymer spinning solution to obtain a mixed solution, and then subject the mixed solution to electrospinning, wet spinning, air spinning or centrifugal spinning to obtain spun fibers, i.e., expandable fibers;

[0008] Step 2: First, the expandable fiber is uniformly mixed with the concrete raw materials, and then water is added and stirred to obtain a concrete slurry. The concrete slurry is then allowed to stand and solidify to obtain a solidified body.

[0009] The third step is to heat the solidified body at a temperature of 200°C to 600°C. When the expandable graphite in the solidified body expands due to the heat, the high-strength concrete can be obtained.

[0010] In the third step, when the heating is completed, the volume of the expandable graphite particles is 10 to 500 times that before the heating.

[0011] In the first step, the size of the expandable graphite particles is 500 nanometers to 50 micrometers.

[0012] In the first step, the weight of the expandable graphite particles is 5wt%-40wt% of the weight of the polymer spinning solution.

[0013] In the first step, the solute of the polymer spinning solution is a polymer and the solvent is an organic solvent;

[0014] The polymer is any one of polyacrylonitrile, polyamide, polyvinyl alcohol, polyvinyl pyrrolidone, cuprammonium fiber, viscose fiber, aramid fiber, silk fiber, cotton fiber, wool fiber, or any mixture thereof;

[0015] The organic solvent is any one of dimethylformamide, dimethyl sulfoxide, ethanol, methanol, acetone, and ethyl acetate, or any mixture thereof.

[0016] In the second step, the weight of the expandable fiber is 1 wt% to 20 wt% of the weight of the concrete raw material.

[0017] In the second step, allowing the concrete slurry to stand and solidify to obtain a solidified body means allowing the concrete slurry to stand at room temperature for 3 to 30 days to obtain a solidified body.

[0018] In the first step, uniformly mixing the expandable graphite particles with the polymer spinning solution means uniformly dispersing the expandable graphite particles in the polymer spinning solution by mechanical stirring or ultrasonic dispersion.

[0019] In the first step, the diameter of the expandable fiber is 1 micrometer to 3 mm, and the length of the expandable fiber is 1 mm to 100 mm.

[0020] A product is high-strength concrete, which is prepared according to the above-mentioned method for preparing high-strength concrete based on expandable fibers.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. In a method for preparing high-strength concrete based on expandable fibers and a product thereof, expandable fibers containing expandable graphite particles are first prepared, the expandable fibers are then uniformly mixed with concrete raw materials, water is added and stirred to obtain a concrete slurry, the concrete slurry is then allowed to stand and solidify to obtain a solidified body, and finally the solidified body is heated to cause the expandable graphite in the solidified body to expand due to heat, thereby obtaining the high-strength concrete. The advantages of this design include: first, by adding expandable fibers to the concrete raw materials, the strength of the final product, high-strength concrete, can be improved; second, when the solidified body is heated for heat treatment, the expandable graphite Expanded graphite expands when heated, and the expanded volume can fill the gaps between the fiber and concrete, thereby reducing the gaps between the fiber and concrete, eliminating defects in the prior art, and further enhancing the interfacial properties, which greatly improves the strength of the concrete. Furthermore, during the curing process, concrete slurry forms certain bubbles and voids, causing its mechanical properties to deteriorate. In this design, although the curing of the concrete slurry still forms bubbles or voids, since the expandable graphite expands after heat treatment, some of the bubbles or voids are occupied by the expanded graphite, further improving the overall mechanical strength of the resulting concrete. Therefore, the present invention not only has better interfacial properties, but also can improve the mechanical strength of the final product.

[0023] 2. In the present invention's method for preparing high-strength concrete based on expandable fibers and its product, the expandable fibers added to the concrete are a mixture of expandable graphite and a base fiber raw material (i.e., a polymer spinning solution). Heat treatment of the expandable graphite increases the mechanical strength of the resulting concrete. This means that, to achieve the same strength in concrete, the fiber content required in this design is far less than that required in conventional fiber / concrete combinations. Furthermore, expandable graphite is extremely inexpensive, resulting in a lower production cost. Therefore, the present invention offers a low production cost.

[0024] 3. In the present invention's method for preparing high-strength concrete based on expandable fibers and its product, the concrete slurry must be cured before heat treatment (i.e., heating the solidified body), rather than directly heat-treated. This is because concrete requires a certain amount of moisture to cure. Direct heat treatment of the concrete slurry would quickly deplete the moisture, hindering the final concrete's formation and potentially causing cracking, significantly reducing mechanical strength, and undermining the foundation for the expandable graphite. Therefore, the present invention ensures superior mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an operational flow chart of the present invention.

[0026] Figure 2Schematic diagram comparing the effects of the expandable fiber on the fiber / concrete interface before and after expansion in the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] See also Figure 1 — Figure 2 , a method for preparing high-strength concrete based on expandable fibers, the method comprising the following steps:

[0029] The first step is to uniformly mix expandable graphite particles with a polymer spinning solution to obtain a mixed solution, and then subject the mixed solution to electrospinning, wet spinning, air spinning or centrifugal spinning to obtain spun fibers, i.e., expandable fibers;

[0030] Step 2: First, the expandable fiber is uniformly mixed with the concrete raw materials, and then water is added and stirred to obtain a concrete slurry. The concrete slurry is then allowed to stand and solidify to obtain a solidified body.

[0031] The third step is to heat the solidified body at a temperature of 200°C to 600°C. When the expandable graphite in the solidified body expands due to the heat, the high-strength concrete can be obtained.

[0032] In the third step, when the heating is completed, the volume of the expandable graphite particles is 10 to 500 times that before the heating.

[0033] In the first step, the size of the expandable graphite particles is 500 nanometers to 50 micrometers.

[0034] In the first step, the weight of the expandable graphite particles is 5wt%-40wt% of the weight of the polymer spinning solution.

[0035] In the first step, the solute of the polymer spinning solution is a polymer and the solvent is an organic solvent;

[0036] The polymer is any one of polyacrylonitrile, polyamide, polyvinyl alcohol, polyvinyl pyrrolidone, cuprammonium fiber, viscose fiber, aramid fiber, silk fiber, cotton fiber, wool fiber, or any mixture thereof;

[0037] The organic solvent is any one of dimethylformamide, dimethyl sulfoxide, ethanol, methanol, acetone, and ethyl acetate, or any mixture thereof.

[0038] In the second step, the weight of the expandable fiber is 1 wt% to 20 wt% of the weight of the concrete raw material.

[0039] In the second step, allowing the concrete slurry to stand and solidify to obtain a solidified body means allowing the concrete slurry to stand at room temperature for 3 to 30 days to obtain a solidified body.

[0040] In the first step, uniformly mixing the expandable graphite particles with the polymer spinning solution means uniformly dispersing the expandable graphite particles in the polymer spinning solution by mechanical stirring or ultrasonic dispersion.

[0041] In the first step, the diameter of the expandable fiber is 1 micrometer to 3 mm, and the length of the expandable fiber is 1 mm to 100 mm.

[0042] A product is high-strength concrete, which is prepared according to the above-mentioned method for preparing high-strength concrete based on expandable fibers.

[0043] The principle of the present invention is described as follows:

[0044] See also Figure 2 Before the expandable graphite in the expandable fiber expands due to heat, gaps exist between the fiber and concrete, resulting in a weak interface and reducing the overall strength of the concrete. After heat treatment, the expandable graphite expands (the expansion process is similar to blowing up a balloon, first filling the gap directly above the graphite, and then spreading to both sides after hitting the concrete above), filling the gaps (the interface is mainly determined by the bond between the fiber and concrete; the closer the contact, the better the interface. Ordinary fiber / concrete has small gaps, resulting in poor interface performance). This allows the fiber and concrete to come into contact, reducing the gap between the fiber and concrete, thereby strengthening the interface performance and significantly increasing the strength of the final concrete.

[0045] The mixed solution in the present invention must have a certain viscosity to be able to be spun.

[0046] The concrete raw materials in the present invention refer to substances that can be left to solidify after adding water, such as any one of cement, stone, sand, and aggregate or any mixture thereof.

[0047] The reason why the weight of the expandable graphite particles in the present invention is preferably 5wt%-40wt% of the weight of the polymer spinning solution is that: if the weight of the expandable graphite is less than 5wt%, no significant enhancement of the mechanical strength of the concrete can be achieved; if the weight of the expandable graphite is greater than 40wt%, the subsequent spinning difficulty will be increased, resulting in the spun yarn being easily broken.

[0048] The reason why the weight of the expandable fibers is preferably 1wt%-20wt% of the weight of the concrete raw materials in the present invention is that if the weight of the expandable fibers is less than 1wt%, no significant enhancement of the mechanical strength of the concrete can be achieved. If the weight of the expandable fibers is greater than 20wt%, it is easy to exceed the threshold, resulting in a decrease in the mechanical strength of the concrete and a lower cost-effectiveness.

[0049] Example 1:

[0050] See also Figure 1 — Figure 2 , a method for preparing high-strength concrete based on expandable fibers, the method comprising the following steps:

[0051] The first step is to uniformly mix expandable graphite particles (preferably the expandable graphite particles have a size of 500 nanometers to 50 microns) with a polymer spinning solution to obtain a mixed solution, and then subject the mixed solution to electrospinning, wet spinning, air spinning or centrifugal spinning to obtain spun fibers, i.e., expandable fibers.

[0052] Step 2: First, the expandable fiber is uniformly mixed with the concrete raw materials, and then water is added and stirred to obtain a concrete slurry. The concrete slurry is then allowed to stand and solidify to obtain a solidified body (preferably, the concrete slurry is allowed to stand at room temperature for 3-30 days to obtain a solidified body);

[0053] Step 3: Heating the solidified body at a temperature of 200°C to 600°C (preferably 400°C). When the expandable graphite in the solidified body expands due to the heat, the high-strength concrete can be obtained (preferably, when the heating is completed, the volume of the expandable graphite particles is 10 to 500 times that before heating).

[0054] Example 2:

[0055] The basic content is the same as Example 1, except that:

[0056] In the first step, the weight of the expandable graphite particles is 5wt%-40wt% of the weight of the polymer spinning solution.

[0057] In the second step, the weight of the expandable fiber is 1 wt% to 20 wt% of the weight of the concrete raw material.

[0058] Example 3:

[0059] The basic content is the same as Example 1, except that:

[0060] First, expandable graphite with a particle size of 1 mm is subjected to high-speed ball milling to obtain expandable graphite particles with a particle size of 80 μm after ball milling for 5 hours. Then, 10 wt% of the expandable graphite particles are mixed into a 20 wt% polymer spinning solution (solute: polyacrylonitrile, solvent: DMF) by mechanical stirring. Then, expandable fibers with a diameter of 2 mm are prepared by wet spinning and cut into 50 mm lengths. Then, 3 wt% of the expandable fibers are added to the concrete raw materials and stirred for 5 minutes. Then, water is added to obtain a concrete slurry. The concrete slurry is then allowed to stand and cure for 14 days to obtain a cured body. The cured body is then heat-treated in an oven at 300°C for 10 minutes to obtain the final high-strength concrete.

[0061] A comparative experiment was conducted between the high-strength concrete and ordinary concrete. The three-point bending strength of ordinary concrete is about 15 MPa, while the three-point bending strength of the high-strength concrete is greater than or equal to 30 MPa.

[0062] Example 4:

[0063] The basic content is the same as Example 1, except that:

[0064] In the first step, the solute of the polymer spinning solution is a polymer and the solvent is an organic solvent;

[0065] The polymer is any one of polyacrylonitrile, polyamide, polyvinyl alcohol, polyvinyl pyrrolidone, cuprammonium fiber, viscose fiber, aramid fiber, silk fiber, cotton fiber, wool fiber, or any mixture thereof;

[0066] The organic solvent is any one of dimethylformamide, dimethyl sulfoxide, ethanol, methanol, acetone, and ethyl acetate, or any mixture thereof.

[0067] Example 5:

[0068] The basic content is the same as Example 1, except that:

[0069] A product is high-strength concrete, which is prepared according to the above-mentioned method for preparing high-strength concrete based on expandable fibers.

[0070] The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modifications or changes made by ordinary technicians in this field based on the contents disclosed in the present invention should be included in the protection scope recorded in the claims.

Claims

1. A method for preparing high-strength concrete based on expandable fibers, characterized in that: The preparation method comprises the following steps: The first step is to uniformly mix expandable graphite particles with a polymer spinning solution to obtain a mixed solution, and then subject the mixed solution to electrospinning, wet spinning, air spinning or centrifugal spinning to obtain spun fibers, i.e., expandable fibers; Step 2: First, the expandable fiber is uniformly mixed with the concrete raw materials, and then water is added and stirred to obtain a concrete slurry. The concrete slurry is then allowed to stand and solidify to obtain a solidified body. Step 3: Heating the solidified body at a temperature of 200°C to 600°C. When the expandable graphite in the solidified body expands due to the heat, the expansion increases the volume of the graphite particles, thereby filling the gaps between the fiber and concrete, thereby obtaining the high-strength concrete. In the first step, the weight of the expandable graphite particles is 5wt%-40wt% of the weight of the polymer spinning solution.

2. The method for preparing high-strength concrete based on expandable fibers according to claim 1, wherein: In the third step, when the heating is completed, the volume of the expandable graphite particles is 10 to 500 times that before the heating.

3. The method for preparing high-strength concrete based on expandable fibers according to claim 1 or 2, characterized in that: In the first step, the size of the expandable graphite particles is 500 nanometers to 50 micrometers.

4. The method for preparing high-strength concrete based on expandable fibers according to claim 1 or 2, characterized in that: In the first step, the solute of the polymer spinning solution is a polymer and the solvent is an organic solvent; The polymer is any one of polyacrylonitrile, polyamide, polyvinyl alcohol, polyvinyl pyrrolidone, cuprammonium fiber, viscose fiber, aramid fiber, silk fiber, cotton fiber, wool fiber, or any mixture thereof; The organic solvent is any one of dimethylformamide, dimethyl sulfoxide, ethanol, methanol, acetone, and ethyl acetate, or any mixture thereof.

5. The method for preparing high-strength concrete based on expandable fibers according to claim 1 or 2, characterized in that: In the second step, the weight of the expandable fiber is 1 wt% to 20 wt% of the weight of the concrete raw material.

6. The method for preparing high-strength concrete based on expandable fibers according to claim 1 or 2, characterized in that: In the second step, allowing the concrete slurry to stand and solidify to obtain a solidified body means allowing the concrete slurry to stand at room temperature for 3 to 30 days to obtain a solidified body.

7. The method for preparing high-strength concrete based on expandable fibers according to claim 1 or 2, characterized in that: In the first step, uniformly mixing the expandable graphite particles with the polymer spinning solution means uniformly dispersing the expandable graphite particles in the polymer spinning solution by mechanical stirring or ultrasonic dispersion.

8. The method for preparing high-strength concrete based on expandable fibers according to claim 1 or 2, characterized in that: In the first step, the diameter of the expandable fiber is 1 micrometer to 3 mm, and the length of the expandable fiber is 1 mm to 100 mm.

9. A product characterized by: The product is high-strength concrete, which is prepared according to the method for preparing high-strength concrete based on expandable fibers according to claim 1 or 2.

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