A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material

Abstract

This invention relates to the field of low-carbon cement materials, specifically disclosing a preparation process for a low-carbon solid waste-based high-strength steel fiber concrete material, comprising the following steps: (1) Copper-plated steel fibers are dispersed in coal gangue powder and then calcined in a protective atmosphere. After completion, the mixture is cooled to room temperature, and the surface-modified steel fibers are separated. (2) Alkali solution is added to the surface-modified steel fibers, mixed, heated and kept warm, and then calcium ion solution is added and mixed. After drying, reinforced steel fibers are obtained. (3) Granulated blast furnace slag powder, solid waste sulfate components, alkaline components, sand, the reinforced steel fibers, water-reducing agent, etc. are used as raw materials, mixed, and then mixed with mixing water and stirred evenly to obtain the concrete material. This invention can not only effectively reduce the problem of decreased mechanical properties of steel fibers in supersulfate cement-based concrete materials caused by carbon dioxide, but also improve the bonding force between steel fibers and the concrete matrix, promoting the improvement of strength.

Description

Technical Field

[0001] This invention relates to the field of low-carbon cement materials, specifically to a preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material. Background Technology

[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of this invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Supersulfate cement is a typical low-carbon cementitious material. It is made primarily from granulated blast furnace slag, an industrial solid waste, supplemented with sulfate components and appropriate amounts of alkaline components. Therefore, its production does not require the high-temperature calcination process of traditional silicate cement, which not only significantly reduces energy consumption and carbon emissions, making it more environmentally friendly, but also allows for the utilization and disposal of large amounts of industrial solid waste, which is more in line with the current sustainable development requirements of the cement industry.

[0004] However, persulfate cement suffers from insufficient early strength. Although adding steel fibers can effectively improve its early strength, the hydration products of persulfate cement are mainly ettringite and calcium silicate hydrate, unlike traditional silicate cement which contains a large amount of calcium hydroxide, an alkaline hydration product. This difference ensures the ability of the added steel fibers to resist acidic corrosion caused by carbon dioxide. This is because the hydration products of persulfate cement do not contain carbon dioxide-consuming components like calcium hydroxide in traditional silicate cement. Furthermore, the ettringite gradually decomposes under the influence of carbon dioxide in the air. This corrosion causes more pores to form in the persulfate cement structure. Once carbon dioxide enters, it further accelerates the corrosion of the steel fibers in a humid environment, resulting in a decrease in the mechanical properties of the persulfate cement structure. In addition, steel fibers generally have insufficient bonding strength with the cement matrix. During stress, the steel fibers are easily pulled out of the cement matrix, leading to a decrease in the strength-enhancing effect of the steel fibers on the cement matrix. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material. This process not only effectively reduces the mechanical property degradation caused by carbon dioxide in supersulfate cement-based concrete materials but also improves the bonding force between the steel fibers and the concrete matrix, thereby enhancing strength. Specifically, the technical solution of this invention is as follows.

[0006] A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material includes the following steps:

[0007] (1) Copper-plated steel fibers are dispersed in coal gangue powder and then calcined in a protective atmosphere at a temperature between the melting points of copper and iron. After completion, the mixture is cooled to room temperature, and the surface-modified steel fibers are separated for later use.

[0008] (2) After adding alkaline solution to the surface-modified steel fiber and mixing it evenly, heat and keep it warm, then add calcium ion solution and mix it evenly, and dry it to obtain reinforced steel fiber.

[0009] (3) The pretreated coal gangue powder separated in step (1) is mixed with tetraethyl orthosilicate-hydrophobic agent-anhydrous ethanol mixture and dried. Then the resulting mixture is mixed with silane coupling agent-anhydrous ethanol treatment solution and added to a suspension formed by polyvinyl alcohol-nano silica-water. After mixing, it is spray-dried to obtain modified coal gangue powder.

[0010] (4) Using granulated blast furnace slag powder, solid waste sulfate components, alkaline components, sand, the modified coal gangue powder, the reinforced steel fiber, and water-reducing agent as raw materials, mix them evenly and then add mixing water to stir evenly to obtain the concrete material.

[0011] Further, in step (1), the mass ratio of the copper-plated steel fiber to the coal gangue powder is 1:10~20. Optionally, the fineness of the coal gangue powder is 250~400 mesh. The length of the copper-plated steel fiber is 5~13 mm.

[0012] Further, in step (1), the calcination treatment is carried out at a temperature of 1095~1120℃ for 70~90 min. Optionally, the protective atmosphere includes at least one of nitrogen, argon, etc.

[0013] Further, in step (2), the ratio of the surface-modified steel fiber to the alkaline solution is 1g:2~3mL. Optionally, the mass fraction of the alkaline solution is not less than 35%. The alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, etc.

[0014] Further, in step (2), the heat preservation time is 45~60 minutes. Optionally, the heating temperature is 50~70℃.

[0015] Further, in step (2), the molar ratio of calcium ions to hydroxide ions provided by the alkaline solution is 1~1.15:1. Optionally, the calcium ion solution includes at least one of calcium nitrate, calcium acetate, calcium gluconate solution, etc.

[0016] Further, in step (3), the ratio of coal gangue powder to the mixed liquid is 1g:1.4~1.8mL.

[0017] Further, in step (3), the mass ratio of tetraethyl orthosilicate, hydrophobic agent, and anhydrous ethanol is 1:0.035~0.042:2.5~3.5. Optionally, the hydrophobic agent includes at least one of methyltrimethoxysilane, perfluorooctyltrichlorosilane, oleic acid, etc.

[0018] Further, in step (3), the ratio of the mixture to the treatment liquid is 1g:0.2~0.3ml.

[0019] Further, in step (3), the mass fraction of the silane coupling agent in the treatment solution is 1~1.5%. Optionally, the silane coupling agent includes at least one of KH550, KH560, KH570, A171, A172, etc.

[0020] Further, in step (3), the ratio of the mixture to the suspension is 1g: 5~6mL.

[0021] Furthermore, in step (3), the polyvinyl alcohol in the suspension is in a saturated state, and the content of the nano silica is 17~23g / L.

[0022] Further, in step (4), the proportions of each component in the raw material are as follows: 75-85 parts by weight of granulated blast furnace slag powder, 10-20 parts by weight of solid waste sulfate component, 3-7 parts by weight of alkaline component, 92-116 parts by weight of sand, 2-5 parts by weight of the modified coal gangue powder, 8-14 parts by weight of the reinforced steel fiber, 0.12-0.17 parts by weight of water reducing agent, and 30-35 parts by weight of mixing water.

[0023] Furthermore, in step (4), the solid waste sulfate component includes at least one of the following: desulfurized gypsum, phosphogypsum, fluorogypsum, desulfurized ash, etc.

[0024] Furthermore, in step (4), the alkaline component includes at least one of silicate cement clinker, carbide slag, etc.

[0025] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0026] (1) In this invention, copper-plated steel fibers and coal gangue powder are first calcined together at a temperature between the melting points of copper and iron. This causes the copper plating on the surface of the steel fibers to melt and adhere to the coal gangue particles. During this process, the organic matter in the coal gangue is pyrolyzed to form a porous structure, and the high-temperature activation of the coal gangue promotes the enhancement of its hydration reaction activity. When cooled, the copper plating on the surface of the steel fibers re-solidifies, anchoring the coal gangue particles to the steel fibers, thus roughening the surface of the steel fibers and helping to increase the bonding force between the steel fibers and the concrete matrix. Furthermore, the surface-modified steel fibers obtained by the above treatment are first treated with an alkaline solution. This not only reactivates the coal gangue particles on the surface of the steel fibers, further enhancing their hydration reaction activity, but also converts the alkaline solution stored in the pores of the coal gangue into calcium hydroxide through the calcium ion solution. When the reinforced steel fibers obtained through the above treatment are added to concrete, on the one hand, the coarsened surface of the steel fibers from the coal gangue particles provides a stronger bond with the hardened concrete matrix, increasing the difficulty of separation and thus improving the mechanical strength of the concrete. On the other hand, the calcium hydroxide stored in the coal gangue reacts with the active silica in the coal gangue to form calcium silicate hydrate (CSH) cementitious products. This not only increases the bonding force between the coal gangue particles and the steel fibers but also increases the bonding force between the steel fibers and the concrete matrix, further enhancing the mechanical strength of the concrete. Furthermore, the calcium hydroxide stored in the coal gangue can also consume the introduced carbon dioxide, mitigating the problem of decreased mechanical strength in concrete caused by carbon dioxide.

[0027] (2) In this invention, the porous coal gangue produced after preparing the surface-modified steel fibers is first treated with tetraethyl orthosilicate-hydrophobic agent-anhydrous ethanol, then treated with a coupling agent, and then coated with polyvinyl alcohol and nano-silica to form a hybrid coating film, which seals the tetraethyl orthosilicate and hydrophobic agent inside the coal gangue particles to form modified coal gangue powder. When this modified coal gangue powder is added to the concrete material of this invention, the coating film can be used to prevent the hydrophobic agent in the modified coal gangue powder from being released in the early stage of hydration of granulated blast furnace slag powder, which would lead to insufficient hydration reaction and thus affect the mechanical properties of the concrete material. As the nano-silica in the coating reacts under the action of calcium hydroxide released by the alkaline component, the internal coal gangue particles are exposed. At this time, the alkaline component enters the coal gangue particles, causing the tetraethyl orthosilicate in them to hydrolyze and release ethanol. After diffusing to the surroundings, it constructs a diffusion zone of the hydrophobic agent around the coal gangue particles, allowing the hydrophobic agent to diffuse more evenly to the surroundings, forming a more comprehensive and effective hydrophobic system. This system can block external moisture from entering the interior of the concrete material, thereby blocking the conditions for carbonation reaction. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0029] Figure 1 The images below show the reinforced steel fiber (A) and modified coal gangue powder samples (B) from Example 1.

[0030] Figure 2 The following are the initial compressive strength test diagrams for Examples 1-5 and Example 7.

[0031] Figure 3 The following are images of reinforced steel fiber (A) and modified coal gangue powder samples (B) from Example 2.

[0032] Figure 4 The following are images of reinforced steel fiber (A) and modified coal gangue powder samples (B) from Example 3.

[0033] Figure 5 The following image shows steel fiber (A) and modified coal gangue powder samples (B) from Example 4.

[0034] Figure 6 The images below show the reinforced steel fiber (A) and modified coal gangue powder samples (B) from Example 5.

[0035] Figure 7 The following is a diagram showing the reinforced steel fiber (A) and initial compressive strength test results (B) of Example 6.

[0036] Figure 8 The following image shows the reinforced steel fiber (A) and modified coal gangue powder sample (B) from Example 7. Detailed Implementation

[0037] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0038] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as those skilled in the art. The reagents or raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods or product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein can be applied to the methods of this invention. The technical solution of this invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0039] Example 1: A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material, comprising the following steps:

[0040] (1) Copper-plated steel fibers with a length of 13 mm and 300-mesh coal gangue powder were mixed at a mass ratio of 1:15 and stirred evenly. Then, the mixture was heated to 1100℃ at a rate of 20℃ / min and held for 80 min under a nitrogen protective atmosphere. After completion, the mixture was cooled to room temperature under the protective atmosphere and then sieved to obtain surface-modified steel fibers and pretreated coal gangue powder, which were then set aside for later use.

[0041] (2) The surface-modified steel fibers were mixed with 40 wt.% sodium hydroxide solution at a ratio of 1 g: 2.5 mL and stirred until homogeneous. The mixture was then sealed and heated in a water bath to 60°C for 55 min. Then, calcium nitrate solution was added at a molar ratio of calcium ions to sodium hydroxide solution of 1.05:1. After stirring until homogeneous, the mixture was heated to 100°C and dried to remove moisture, yielding reinforced steel fibers (e.g., ...). Figure 1 (As shown in A), for future reference.

[0042] (3) Tetraethyl orthosilicate, hydrophobic agent (perfluorooctyltrichlorosilane), and anhydrous ethanol are mixed at a mass ratio of 1:0.038:3 and stirred evenly. Then, the resulting mixture is mixed with the pretreated coal gangue powder at a ratio of 1.6 mL:1 g and stirred evenly. Then, the resulting mixture is mixed with the silane coupling agent-anhydrous ethanol treatment solution at a ratio of 1 g:0.25 mL and stirred evenly. The mass fraction of the silane coupling agent (KH560) in the treatment solution is 1.2%. Then, the suspension is added at a ratio of 1 g:5 mL, which is formed by ultrasonic stirring of polyvinyl alcohol, nano silica, and water. The polyvinyl alcohol is saturated, and the content of nano silica is 21 g / L. Finally, the resulting solid-liquid mixture is spray-dried to obtain modified coal gangue powder (e.g., Figure 1 (As shown in B), for later use.

[0043] (4) Take the following raw materials in the following proportions: 78 parts by weight of granulated blast furnace slag powder, 16 parts by weight of desulfurized gypsum powder, 5 parts by weight of calcium carbide slag powder, 100 parts by weight of river sand, 4 parts by weight of modified coal gangue powder in this embodiment, 11 parts by weight of reinforced steel fiber in this embodiment, and 0.15 parts by weight of polycarboxylate superplasticizer. Mix the above raw materials and mechanically stir for 3 minutes, then add 32 parts by weight of mixing water and continue stirring for 2 minutes to obtain concrete material.

[0044] Performance Testing: 1. The concrete material prepared in this embodiment is poured into a mold, and after hardening, it is demolded and cured for 7 days to obtain specimens. Then, a portion of the specimens are tested according to the "Test Method for Strength of Cement Mortar (ISO Method)" GB / T17671-2021 to obtain the initial compressive strength (e.g., Figure 2 (As shown). 2. The other specimen was carbonized according to GB / T 42277-2022 "Test Method for Carbonation of Cement Mortar", and then the carbonation compressive strength of the obtained specimen was tested. The retention rate of the carbonation compressive strength relative to the initial compressive strength was calculated. The results are shown in the table below:

[0045]

[0046] Example 2: A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material, comprising the following steps:

[0047] (1) Copper-plated steel fibers with a length of 13 mm and coal gangue powder with a mesh size of 250 were mixed at a mass ratio of 1:20 and stirred evenly. Then, the mixture was heated to 1095 °C at a rate of 20 °C / min and held for 90 min under a nitrogen protective atmosphere. After completion, the mixture was cooled to room temperature under the protective atmosphere and then sieved to obtain surface-modified steel fibers and pretreated coal gangue powder, which were then set aside for later use.

[0048] (2) The surface-modified steel fibers were mixed with 35 wt.% sodium hydroxide solution at a ratio of 1 g: 3 mL and stirred until homogeneous. The mixture was then sealed and heated in a water bath to 50°C for 60 min. Then, calcium acetate solution was added at a molar ratio of calcium ions to sodium hydroxide solution of 1:1. After stirring until homogeneous, the mixture was heated to 100°C and dried to remove moisture, yielding reinforced steel fibers (e.g., ...). Figure 3 (As shown in A), for future reference.

[0049] (3) Tetraethyl orthosilicate, hydrophobic agent (oleic acid), and anhydrous ethanol are mixed at a mass ratio of 1:0.042:3.5 and stirred evenly. Then, the resulting mixture is mixed with the pretreated coal gangue powder at a ratio of 1.4 mL:1 g and stirred evenly. Then, the resulting mixture is mixed with silane coupling agent-anhydrous ethanol treatment solution at a ratio of 1 g:0.2 mL and stirred evenly. The mass fraction of silane coupling agent (KH550) in the treatment solution is 1.5%. Then, the mixture is added to the suspension at a ratio of 1 g:6 mL. The suspension is formed by ultrasonic stirring of polyvinyl alcohol, nano silica, and water. The polyvinyl alcohol is saturated, and the content of nano silica is 23 g / L. Finally, the resulting solid-liquid mixture is spray-dried to obtain modified coal gangue powder (e.g., Figure 3 (As shown in B), for later use.

[0050] (4) Take the following raw materials in the following proportions: 75 parts by weight of granulated blast furnace slag powder, 10 parts by weight of fluorogypsum powder, 3 parts by weight of calcium carbide slag powder, 92 parts by weight of river sand, 2 parts by weight of modified coal gangue powder in this embodiment, 8 parts by weight of reinforcing steel fiber in this embodiment, and 0.12 parts by weight of polycarboxylate superplasticizer. Mix the above raw materials and mechanically stir for 3 minutes, then add 30 parts by weight of mixing water and continue stirring for 2 minutes to obtain concrete material.

[0051] Performance testing: The initial compressive strength (e.g., ...) of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 2 The carbonized compressive strength was calculated, and then the compressive strength retention rate was calculated. The results are shown in the table below:

[0052]

[0053] Example 3: A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material, comprising the following steps:

[0054] 1) Copper-plated steel fibers with a length of 5 mm and 400-mesh coal gangue powder were mixed at a mass ratio of 1:10 and stirred evenly. Then, the mixture was heated to 1120°C at a rate of 20°C / min and held for 70 min under a nitrogen protective atmosphere. After completion, the mixture was cooled to room temperature under the same protective atmosphere and then sieved to obtain surface-modified steel fibers and pretreated coal gangue powder, which were then set aside for later use.

[0055] (2) The surface-modified steel fibers were mixed with 45 wt.% potassium hydroxide solution at a ratio of 1 g: 2 mL and stirred until homogeneous. The mixture was then sealed and heated in a water bath to 45°C for 70 min. Then, calcium nitrate solution was added at a molar ratio of calcium ions to potassium hydroxide solution of 1.15:1. After stirring until homogeneous, the mixture was heated to 100°C and dried to remove moisture, yielding reinforced steel fibers (e.g., ...). Figure 4 (As shown in A), for future reference.

[0056] (3) Tetraethyl orthosilicate, hydrophobic agent (oleic acid), and anhydrous ethanol are mixed at a mass ratio of 1:0.035:2.5 and stirred evenly. Then, the resulting mixture is mixed with the pretreated coal gangue powder at a ratio of 1.8 mL:1 g and stirred evenly. Then, the resulting mixture is mixed with silane coupling agent-anhydrous ethanol treatment solution at a ratio of 1 g:0.3 ml and stirred evenly. The mass fraction of silane coupling agent (KH570) in the treatment solution is 1.0%. Then, the mixture is added to the suspension at a ratio of 1 g:6 mL. The suspension is formed by ultrasonic stirring of polyvinyl alcohol, nano silica, and water, wherein the polyvinyl alcohol is saturated and the content of nano silica is 17 g / L. Finally, the resulting solid-liquid mixture is spray-dried to obtain modified coal gangue powder (e.g., Figure 4(As shown in B), for later use.

[0057] (4) Take the following raw materials in the following proportions: 85 parts by weight of granulated blast furnace slag powder, 20 parts by weight of fluorogypsum powder, 7 parts by weight of calcium carbide slag powder, 116 parts by weight of river sand, 5 parts by weight of modified coal gangue powder in this embodiment, 14 parts by weight of reinforced steel fiber in this embodiment, and 0.17 parts by weight of polycarboxylate superplasticizer. Mix the above raw materials and mechanically stir for 3 minutes, then add 35 parts by weight of mixing water and continue stirring for 2 minutes to obtain concrete material.

[0058] Performance testing: The initial compressive strength (e.g., ...) of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 2 The carbonized compressive strength was calculated, and then the compressive strength retention rate was calculated. The results are shown in the table below:

[0059]

[0060] Example 4: A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material, comprising the following steps:

[0061] Take the following raw materials in the following proportions: 78 parts by weight of granulated blast furnace slag powder, 16 parts by weight of desulfurized gypsum powder, 5 parts by weight of calcium carbide slag powder, 100 parts by weight of river sand, and 11 parts by weight of copper-plated steel fiber with a length of 13mm (e.g. Figure 5 As shown in Figure A), 4 parts by weight of modified coal gangue powder from Example 1 (as shown in Figure A). Figure 5 (As shown in Figure B) 0.15 parts by weight of polycarboxylate superplasticizer. Mix the above raw materials and mechanically stir for 3 minutes, then add 32 parts by weight of mixing water and continue stirring for 2 minutes to obtain concrete material.

[0062] Performance testing: The initial compressive strength (e.g., ...) of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 2 The carbonized compressive strength was calculated, and then the compressive strength retention rate was calculated. The results are shown in the table below:

[0063]

[0064] Example 5: A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material, comprising the following steps:

[0065] (1) Copper-plated steel fibers with a length of 13 mm and 300-mesh coal gangue powder were mixed at a mass ratio of 1:15 and stirred evenly. Then, the mixture was heated to 1100℃ at a rate of 20℃ / min and held for 80 min under a nitrogen protective atmosphere. After completion, the mixture was cooled to room temperature under the protective atmosphere and then sieved to obtain surface-modified steel fibers and pretreated coal gangue powder, which were then set aside for later use.

[0066] (2) Tetraethyl orthosilicate, hydrophobic agent (perfluorooctyltrichlorosilane), and anhydrous ethanol were mixed at a mass ratio of 1:0.038:3 and stirred until homogeneous. The resulting mixture was then mixed with the pretreated coal gangue powder at a ratio of 1.6 mL:1 g and stirred until homogeneous. The resulting mixture was then mixed with a silane coupling agent-anhydrous ethanol treatment solution at a ratio of 1 g:0.25 mL and stirred until homogeneous. The mass fraction of the silane coupling agent (KH560) in the treatment solution was 1.2%. The mixture was then added to the suspension at a ratio of 1 g:5 mL. The suspension was formed by ultrasonic stirring of polyvinyl alcohol, nano-silica, and water, wherein the polyvinyl alcohol was saturated and the nano-silica content was 21 g / L. Finally, the resulting solid-liquid mixture was spray-dried to obtain modified coal gangue powder for later use.

[0067] (3) Take the following proportions of raw materials: 78 parts by weight of granulated blast furnace slag powder, 16 parts by weight of desulfurized gypsum powder, 5 parts by weight of calcium carbide slag powder, 100 parts by weight of river sand, and surface-modified steel fibers (such as those used in this embodiment) Figure 6 11 parts by weight of the modified coal gangue powder (as shown in Figure A) of this embodiment, and 11 parts by weight of the modified coal gangue powder (as shown in Figure A). Figure 6 (As shown in B) 4 parts by weight of polycarboxylate superplasticizer and 0.15 parts by weight of the above raw materials. Mix the above raw materials and mechanically stir for 3 minutes. Then add 32 parts by weight of mixing water and continue stirring for 2 minutes to obtain concrete material.

[0068] Performance testing: The initial compressive strength (e.g., ...) of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 2 The carbonized compressive strength was calculated, and then the compressive strength retention rate was calculated. The results are shown in the table below:

[0069]

[0070] Example 6: A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material, comprising the following steps:

[0071] Take the following raw materials in the following proportions: 75 parts by weight of granulated blast furnace slag powder, 10 parts by weight of fluorogypsum powder, 3 parts by weight of calcium carbide slag powder, 92 parts by weight of river sand, and the reinforcing steel fiber from Example 2 (such as...). Figure 7 (As shown in Figure A) 8 parts by weight, polycarboxylate superplasticizer 0.12 parts by weight. Mix the above raw materials and mechanically stir for 3 minutes, then add 30 parts by weight of mixing water and continue stirring for 2 minutes to obtain concrete material.

[0072] Performance testing: The initial compressive strength (e.g., ...) of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 7 The compressive strength was calculated (as shown in B), and then the compressive strength retention rate was calculated. The results are shown in the table below:

[0073]

[0074] Example 7: A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material, comprising the following steps:

[0075] (1) Copper-plated steel fibers with a length of 5 mm and 400-mesh coal gangue powder were mixed at a mass ratio of 1:10 and stirred evenly. Then, the mixture was heated to 1120°C at a rate of 20°C / min and held for 70 min under a nitrogen protective atmosphere. After completion, the mixture was cooled to room temperature under the protective atmosphere and then sieved to obtain surface-modified steel fibers and pretreated coal gangue powder, which were then set aside for later use.

[0076] (2) The surface-modified steel fibers were mixed with 45 wt.% potassium hydroxide solution at a ratio of 1 g: 2 mL and stirred until homogeneous. The mixture was then sealed and heated in a water bath to 45°C for 70 min. Then, calcium nitrate solution was added at a molar ratio of calcium ions to potassium hydroxide solution of 1.15:1. After stirring until homogeneous, the mixture was heated to 100°C and dried to remove moisture, yielding reinforced steel fibers (e.g., ...). Figure 8 (As shown in A), for future reference.

[0077] (3) The hydrophobic agent (oleic acid) and anhydrous ethanol were mixed at a mass ratio of 0.035:2.5 and stirred evenly. Then, the resulting mixture was mixed with the pretreated coal gangue powder at a ratio of 1.8 mL:1 g and stirred evenly. Then, the resulting mixture was mixed with the silane coupling agent-anhydrous ethanol treatment solution at a ratio of 1 g:0.3 ml and stirred evenly. The mass fraction of the silane coupling agent (KH570) in the treatment solution was 1.0%. Then, the suspension was added at a ratio of 1 g:6 mL, which was formed by ultrasonic stirring of polyvinyl alcohol, nano silica and water, wherein the polyvinyl alcohol was saturated and the content of nano silica was 17 g / L. Finally, the resulting solid-liquid mixture was spray-dried to obtain modified coal gangue powder (e.g., Figure 8 (As shown in B), for later use.

[0078] (4) Take the following raw materials in the following proportions: 85 parts by weight of granulated blast furnace slag powder, 20 parts by weight of fluorogypsum powder, 7 parts by weight of calcium carbide slag powder, 116 parts by weight of river sand, 5 parts by weight of modified coal gangue powder in this embodiment, 14 parts by weight of reinforced steel fiber in this embodiment, and 0.17 parts by weight of polycarboxylate superplasticizer. Mix the above raw materials and mechanically stir for 3 minutes, then add 35 parts by weight of mixing water and continue stirring for 2 minutes to obtain concrete material.

[0079] Performance testing: The initial compressive strength (e.g., ...) of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 2The carbonized compressive strength was calculated, and then the compressive strength retention rate was calculated. The results are shown in the table below:

[0080]

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation process for a low-carbon solid waste-based high-strength steel fiber reinforced concrete material, characterized in that, Includes the following steps: (1) Copper-plated steel fibers are dispersed in coal gangue powder and then calcined in a protective atmosphere at a temperature between the melting points of copper and iron. After the calcination is completed, the fibers are cooled to room temperature and the surface-modified steel fibers are separated for later use. The mass ratio of copper-plated steel fibers to coal gangue powder is 1:10~20. The calcination temperature is 1095~1120℃ and the time is 70~90min. (2) After adding alkaline solution to the surface-modified steel fiber and mixing it evenly, heat and keep it warm, then add calcium ion solution and mix it evenly, and dry it to obtain reinforced steel fiber. (3) The pretreated coal gangue powder separated in step (1) is mixed with tetraethyl orthosilicate-hydrophobic agent-anhydrous ethanol mixture and dried. Then the mixture is mixed with silane coupling agent-anhydrous ethanol treatment solution and added to a suspension formed by polyvinyl alcohol-nano silica-water. After mixing, it is spray-dried to obtain modified coal gangue powder. (4) Using granulated blast furnace slag powder, solid waste sulfate components, alkaline components, sand, the modified coal gangue powder, the reinforced steel fiber, and water-reducing agent as raw materials, mix them evenly and then add mixing water to stir evenly to obtain the concrete material.

2. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (1), the fineness of the coal gangue powder is 250~400 mesh.

3. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (1), the length of the copper-plated steel fiber is 5~13mm.

4. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (2), the ratio of the surface-modified steel fiber to the alkaline solution is 1g:2~3mL.

5. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (2), the mass fraction of the alkaline solution is not less than 35%.

6. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (2), the alkaline solution includes at least one of sodium hydroxide solution and potassium hydroxide solution.

7. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (2), the heat preservation time is 45~60 minutes.

8. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (2), the heating temperature is 50~70℃.

9. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (2), the calcium ion solution includes at least one of calcium nitrate, calcium acetate, and calcium gluconate solution.

10. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (2), the molar ratio of calcium ions to hydroxide ions provided by the alkaline solution is 1~1.15:

1.

11. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (3), the ratio of coal gangue powder to the mixed liquid is 1g: 1.4~1.8mL.

12. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (3), the mass ratio of tetraethyl orthosilicate, hydrophobic agent and anhydrous ethanol is 1:0.035~0.042:2.5~3.

5.

13. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (3), the ratio of the mixture to the treatment liquid is 1g:0.2~0.3ml.

14. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (3), the silane coupling agent includes at least one of KH550, KH560, KH570, A171, and A172.

15. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (3), the mass fraction of the silane coupling agent in the treatment solution is 1~1.5%.

16. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (3), the hydrophobic agent includes at least one of methyltrimethoxysilane, perfluorooctyltrichlorosilane, and oleic acid.

17. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (3), the ratio of the mixture to the suspension is 1g: 5~6mL.

18. The preparation process of the low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to claim 1, characterized in that, In step (3), the polyvinyl alcohol in the suspension is saturated, and the content of the nano silica is 17~23g / L.

19. The preparation process of low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to any one of claims 1-18, characterized in that, In step (4), the proportions of each component in the raw material are as follows: 75-85 parts by weight of granulated blast furnace slag powder, 10-20 parts by weight of solid waste sulfate component, 3-7 parts by weight of alkaline component, 92-116 parts by weight of sand, 2-5 parts by weight of modified coal gangue powder, 8-14 parts by weight of reinforced steel fiber, 0.12-0.17 parts by weight of water reducing agent, and 30-35 parts by weight of mixing water.

20. The preparation process of low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to any one of claims 1-18, characterized in that, In step (4), the solid waste sulfate component includes at least one of desulfurized gypsum, phosphogypsum, fluorogypsum, and desulfurized ash.

21. The preparation process of low-carbon solid waste-based high-strength steel fiber reinforced concrete material according to any one of claims 1-18, characterized in that, In step (4), the alkaline component includes at least one of silicate cement clinker and carbide slag.

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