A solid waste-based composite cementitious material and its preparation method

Abstract

This invention discloses a solid waste-based composite cementitious material and its preparation method, relating to the field of solid waste recycling technology. The invention involves copper-plating silica and then adding it to concrete to enhance its strength. By modifying carbon fibers with methyl acrylate and poly(ethylene glycol) methacrylate, the hydrophilicity of the modified carbon fibers is enhanced, improving their compatibility with the concrete matrix, thereby reducing the porosity of the concrete matrix and increasing its strength. This invention combines copper-plated silica with modified carbon fibers and further modifies carbide slag, fly ash, and silica fume using γ-aminopropyltriethoxysilane to improve the dispersibility of the copper-plated silica, thus improving the compatibility of the silica-carbon fiber composite in the concrete matrix and enhancing its strength.

Description

Technical Field

[0001] This invention relates to the field of solid waste recycling technology, specifically to a solid waste-based composite cementitious material and its preparation method. Background Technology

[0002] With the acceleration of global industrialization, the output of industrial solid waste is constantly increasing, such as coal gangue, calcium carbide slag, desulfurization gypsum, aluminum ash, and steel slag. The large-scale accumulation of these solid wastes not only occupies land resources but also may pollute the environment. Therefore, how to effectively utilize these solid wastes and achieve resource recycling has become an urgent problem to be solved.

[0003] In the field of building materials, traditional cementitious materials such as cement consume large amounts of natural mineral resources during production and have high carbon emissions. To reduce dependence on natural resources and decrease carbon emissions, researchers have begun exploring the use of industrial solid waste to prepare composite cementitious materials. However, existing concrete materials still have some shortcomings in performance and application. The strength of the materials needs improvement. Furthermore, the physicochemical properties of different solid wastes vary significantly; how to achieve synergistic effects among multiple solid wastes and optimize material performance is also a problem that requires further research.

[0004] To address the aforementioned problems and improve the strength of materials, this invention provides a solid waste-based composite cementitious material and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a solid waste-based composite cementitious material and its preparation method, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing a solid waste-based composite cementitious material, wherein the method comprises: taking carbide slag, slag powder, and silica fume, grinding them to obtain a cementitious material; taking the cementitious material, adding toluene, ultrasonically dispersing it, adding γ-aminopropyltriethoxysilane, stirring for 20-22 hours, centrifuging, washing, and drying to obtain the solid waste-based composite cementitious material.

[0008] In a more optimized manner, the concrete preparation method is as follows: take the solid waste-based composite cementitious material prepared according to claim 1, add gypsum, quicklime, cement, fly ash, and silica-carbon fiber composite, and ball mill at 70-75℃ for 50-60 minutes to obtain concrete.

[0009] In a more optimized manner, the concrete, by weight, comprises the following components: 50-58 parts of solid waste-based composite cementitious material, 10-15 parts of fly ash, 6-10 parts of gypsum, 1-2 parts of quicklime, 5-10 parts of cement, and 3-5 parts of silica-carbon fiber composite.

[0010] A more optimized method for preparing the silica-carbon fiber composite is as follows: Take modified carbon fiber and deionized water, ultrasonically disperse for 50-70 min, add dopamine, stir for 30-35 min, add tris(hydroxymethyl)aminomethane buffer, add hydrochloric acid, adjust the pH to 8.0-8.5, stir at 25-30℃ for 20-24 h, add copper-plated silica, stir at 25-30℃ for 22-24 h, centrifuge, wash, and dry to obtain the silica-carbon fiber composite.

[0011] A more optimized method for preparing the modified carbon fiber is as follows: take pretreated carbon fiber and methanol, disperse them ultrasonically, add methyl acrylate, heat to 50-55℃, stir for 10-14h, add ethylenediamine, stir, centrifuge, wash and dry; add dimethyl sulfoxide, stir for 20-25min, heat to 70-75℃, add poly(ethylene glycol) methacrylate and lithium chloride, stir for 22-26h, centrifuge, wash and dry to obtain the modified carbon fiber.

[0012] A more optimized method for preparing the pretreated carbon fiber is as follows: take carbon fiber and toluene, disperse them ultrasonically, purge with nitrogen, add γ-aminopropyltriethoxysilane, heat to 100-105℃, stir for 20-22h, cool, centrifuge, wash, and dry to obtain the pretreated carbon fiber.

[0013] Ideally, the mass ratio of the carbon fiber to γ-aminopropyltriethoxysilane is (5-6):8.5.

[0014] In a more optimized manner, the preparation method of the copper-plated silicon dioxide is as follows: take copper sulfate solution and sulfuric acid solution, stir evenly to obtain an electrolyte, add silicon dioxide, stir evenly, and perform pulse electrophoretic deposition treatment for 30-40 minutes. The cathode is a copper alloy and the anode is pure titanium. After the pulse electrophoretic deposition is completed, wash and dry to obtain copper-plated silicon dioxide.

[0015] Ideally, the slag powder is S95 grade blast furnace slag powder; and the cement is PO 42.5 cement.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. This invention involves copper plating silicon dioxide and then adding it to concrete to enhance its strength.

[0018] 2. This invention modifies carbon fibers by using methyl acrylate and poly(ethylene glycol) methacrylate, thereby enhancing the hydrophilicity of the modified carbon fibers, improving their compatibility with concrete, reducing the porosity of concrete, and increasing its strength.

[0019] 3. This invention combines copper-plated silica with modified carbon fiber, and also uses γ-aminopropyltriethoxysilane to modify carbide slag, fly ash, and silica fume to improve the dispersibility of copper-plated silica, thereby improving the compatibility of the silica-carbon fiber composite in concrete and enhancing the strength of the concrete. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The sources and types of the substances involved in this invention are not subject to any particular limitation. Exemplary examples include: silicon dioxide: 10nm, type: N10, which can be purchased from Ningbo Jinlei Nanomaterials Technology Co., Ltd.; carbon fiber: 100nm×20-200μm, type: 719803, which can be purchased from Merck; poly(ethylene glycol) methacrylate: type: 409537, which can be purchased from Merck.

[0022] Example 1: A method for preparing a solid waste-based composite cementitious material, comprising the following steps:

[0023] Step 1: Preparation of solid waste-based composite cementitious materials:

[0024] Take 38g of carbide slag, 28g of slag powder, and 4g of silica fume, grind them to obtain a cementitious material; take the cementitious material, add 1000mL of toluene, ultrasonically disperse it, add 15g of γ-aminopropyltriethoxysilane, stir for 21h, centrifuge, wash, and dry to obtain a solid waste-based composite cementitious material.

[0025] Take solid waste-based composite cementitious material, add gypsum, quicklime, cement, fly ash, and silica-carbon fiber composite, and ball mill at 72℃ for 55 minutes to obtain concrete;

[0026] The concrete, by weight, comprises the following components: 55 parts solid waste-based composite cementitious material, 12 parts fly ash, 8 parts gypsum, 1.5 parts quicklime, 8 parts cement, and 4 parts silica-carbon fiber composite.

[0027] Step 2: Preparation of copper-plated silicon dioxide:

[0028] Take 15 mL of 0.3 mol / L copper sulfate solution and 35 mL of 0.7 mol / L sulfuric acid solution, stir well to obtain an electrolyte, add 2 mg / mL of silica, stir well, and perform pulse electrophoretic deposition treatment for 30 min. The cathode is a copper alloy and the anode is pure titanium. After pulse electrophoretic deposition, wash and dry to obtain copper-plated silica.

[0029] Step 3: Preparation of modified carbon fiber:

[0030] Take 5g of carbon fiber and 300mL of toluene, disperse them by ultrasonication, purge with nitrogen, add 8.5g of γ-aminopropyltriethoxysilane, heat to 102℃, stir for 21h, cool, centrifuge, wash and dry to obtain the pretreated carbon fiber;

[0031] Take the pretreated carbon fiber and 300 mL of methanol, disperse them ultrasonically, add 1 g of methyl acrylate, heat to 52 °C, stir for 12 h, add 1 g of ethylenediamine, stir, centrifuge, wash and dry; add 300 mL of dimethyl sulfoxide, stir for 23 min, heat to 72 °C, add 7.2 g of poly(ethylene glycol) methacrylate and 0.1 g of lithium chloride, stir for 24 h, centrifuge, wash and dry to obtain modified carbon fiber;

[0032] Step 4: Preparation of silica-carbon fiber composite:

[0033] Take 25g of modified carbon fiber and 1000mL of deionized water, sonicate for 60min, add 0.5g of dopamine, stir for 32min, add 1.5g of tris(hydroxymethyl)aminomethane buffer, add hydrochloric acid to adjust the pH to 8.3, stir at 28℃ for 22h, add 6g of copper-plated silica, stir at 28℃ for 23h, centrifuge, wash and dry to obtain silica-carbon fiber composite.

[0034] Example 2: A method for preparing a solid waste-based composite cementitious material, comprising the following steps:

[0035] Step 1: Preparation of solid waste-based composite cementitious materials:

[0036] Take 38g of carbide slag, 28g of slag powder, and 4g of silica fume, grind them to obtain a cementitious material; take the cementitious material, add 1000mL of toluene, ultrasonically disperse it, add 15g of γ-aminopropyltriethoxysilane, stir for 20h, centrifuge, wash, and dry to obtain a solid waste-based composite cementitious material.

[0037] Take solid waste-based composite cementitious material, add gypsum, quicklime, cement, fly ash, and silica-carbon fiber composite, and ball mill at 70℃ for 50 minutes to obtain concrete;

[0038] The concrete, by weight, comprises the following components: 50 parts solid waste-based composite cementitious material, 12 parts fly ash, 6 parts gypsum, 1 part quicklime, 5 parts cement, and 3 parts silica-carbon fiber composite.

[0039] Step 2: Preparation of copper-plated silicon dioxide:

[0040] Take 15 mL of 0.3 mol / L copper sulfate solution and 35 mL of 0.7 mol / L sulfuric acid solution, stir well to obtain an electrolyte, add 2 mg / mL of silica, stir well, and perform pulse electrophoretic deposition treatment for 30 min. The cathode is a copper alloy and the anode is pure titanium. After pulse electrophoretic deposition, wash and dry to obtain copper-plated silica.

[0041] Step 3: Preparation of modified carbon fiber:

[0042] Take 5g of carbon fiber and 300mL of toluene, disperse them by ultrasonication, purge with nitrogen, add 8.5g of γ-aminopropyltriethoxysilane, heat to 100℃, stir for 20h, cool, centrifuge, wash and dry to obtain the pretreated carbon fiber;

[0043] Take the pretreated carbon fiber and 300 mL of methanol, disperse them ultrasonically, add 1 g of methyl acrylate, heat to 50 °C, stir for 10 h, add 1 g of ethylenediamine, stir, centrifuge, wash and dry; add 300 mL of dimethyl sulfoxide, stir for 20 min, heat to 70 °C, add 7.2 g of poly(ethylene glycol) methacrylate and 0.1 g of lithium chloride, stir for 22 h, centrifuge, wash and dry to obtain modified carbon fiber;

[0044] Step 4: Preparation of silica-carbon fiber composite:

[0045] Take 25g of modified carbon fiber and 1000mL of deionized water, sonicate for 50min, add 0.5g of dopamine, stir for 30min, add 1.5g of tris(hydroxymethyl)aminomethane buffer, add hydrochloric acid, adjust the pH to 8.0, stir at 25℃ for 20h, add 6g of copper-plated silica, stir at 25℃ for 22h, centrifuge, wash, and dry to obtain silica-carbon fiber composite.

[0046] Example 3: A method for preparing a solid waste-based composite cementitious material, comprising the following steps:

[0047] Step 1: Preparation of solid waste-based composite cementitious materials:

[0048] Take 38g of carbide slag, 28g of slag powder, and 4g of silica fume, grind them to obtain a cementitious material; take the cementitious material, add 1000mL of toluene, ultrasonically disperse it, add 15g of γ-aminopropyltriethoxysilane, stir for 22h, centrifuge, wash, and dry to obtain a solid waste-based composite cementitious material.

[0049] Take solid waste-based composite cementitious material, add gypsum, quicklime, cement, fly ash, and silica-carbon fiber composite, and ball mill at 75℃ for 60 minutes to obtain concrete;

[0050] The concrete, by weight, comprises the following components: 58 parts solid waste-based composite cementitious material, 12 parts fly ash, 10 parts gypsum, 2 parts quicklime, 10 parts cement, and 5 parts silica-carbon fiber composite.

[0051] Step 2: Preparation of copper-plated silicon dioxide:

[0052] Take 15 mL of 0.3 mol / L copper sulfate solution and 35 mL of 0.7 mol / L sulfuric acid solution, stir well to obtain an electrolyte, add 2 mg / mL of silica, stir well, and perform pulse electrophoretic deposition treatment for 30 min. The cathode is a copper alloy and the anode is pure titanium. After pulse electrophoretic deposition, wash and dry to obtain copper-plated silica.

[0053] Step 3: Preparation of modified carbon fiber:

[0054] Take 5g of carbon fiber and 300mL of toluene, disperse them by ultrasonication, purge with nitrogen, add 8.5g of γ-aminopropyltriethoxysilane, heat to 105℃, stir for 22h, cool, centrifuge, wash and dry to obtain the pretreated carbon fiber;

[0055] Take the pretreated carbon fiber and 300 mL of methanol, disperse them ultrasonically, add 1 g of methyl acrylate, heat to 55 °C, stir for 14 h, add 1 g of ethylenediamine, stir, centrifuge, wash and dry; add 300 mL of dimethyl sulfoxide, stir for 25 min, heat to 75 °C, add 7.2 g of poly(ethylene glycol) methacrylate and 0.1 g of lithium chloride, stir for 26 h, centrifuge, wash and dry to obtain modified carbon fiber;

[0056] Step 4: Preparation of silica-carbon fiber composite:

[0057] Take 25g of modified carbon fiber and 1000mL of deionized water, sonicate for 70min, add 0.5g of dopamine, stir for 35min, add 1.5g of tris(hydroxymethyl)aminomethane buffer, add hydrochloric acid, adjust the pH to 8.5, stir at 30℃ for 24h, add 6g of copper-plated silica, stir at 30℃ for 24h, centrifuge, wash, and dry to obtain silica-carbon fiber composite.

[0058] Comparative Example 1: No copper plating was performed on the silicon dioxide; all other aspects were the same as in Example 1.

[0059] Step 1: Preparation of solid waste-based composite cementitious materials:

[0060] Take 38g of carbide slag, 28g of slag powder, and 4g of silica fume, grind them to obtain a cementitious material; take the cementitious material, add 1000mL of toluene, ultrasonically disperse it, add 15g of γ-aminopropyltriethoxysilane, stir for 21h, centrifuge, wash, and dry to obtain a solid waste-based composite cementitious material.

[0061] Take solid waste-based composite cementitious material, add gypsum, quicklime, cement, fly ash, and silica-carbon fiber composite, and ball mill at 72℃ for 55 minutes to obtain concrete;

[0062] The concrete, by weight, comprises the following components: 55 parts solid waste-based composite cementitious material, 12 parts fly ash, 8 parts gypsum, 1.5 parts quicklime, 8 parts cement, and 4 parts silica-carbon fiber composite.

[0063] Step 2: Preparation of modified carbon fiber:

[0064] Take 5g of carbon fiber and 300mL of toluene, disperse them by ultrasonication, purge with nitrogen, add 8.5g of γ-aminopropyltriethoxysilane, heat to 102℃, stir for 21h, cool, centrifuge, wash and dry to obtain the pretreated carbon fiber;

[0065] Take the pretreated carbon fiber and 300 mL of methanol, disperse them ultrasonically, add 1 g of methyl acrylate, heat to 52 °C, stir for 12 h, add 1 g of ethylenediamine, stir, centrifuge, wash and dry; add 300 mL of dimethyl sulfoxide, stir for 23 min, heat to 72 °C, add 7.2 g of poly(ethylene glycol) methacrylate and 0.1 g of lithium chloride, stir for 24 h, centrifuge, wash and dry to obtain modified carbon fiber;

[0066] Step 3: Preparation of silica-carbon fiber composite:

[0067] Take 25g of modified carbon fiber and 1000mL of deionized water, sonicate for 60min, add 0.5g of dopamine, stir for 32min, add 1.5g of tris(hydroxymethyl)aminomethane buffer, add hydrochloric acid to adjust the pH to 8.3, stir at 28℃ for 22h, add 6g of silica, stir at 28℃ for 23h, centrifuge, wash and dry to obtain silica-carbon fiber composite.

[0068] Comparative Example 2: No modification was made to the carbon fiber; everything else was the same as in Example 1.

[0069] Step 1: Preparation of solid waste-based composite cementitious materials:

[0070] Take 38g of carbide slag, 28g of slag powder, and 4g of silica fume, grind them to obtain a cementitious material; take the cementitious material, add 1000mL of toluene, ultrasonically disperse it, add 15g of γ-aminopropyltriethoxysilane, stir for 21h, centrifuge, wash, and dry to obtain a solid waste-based composite cementitious material.

[0071] Take solid waste-based composite cementitious material, add gypsum, quicklime, cement, fly ash, and silica-carbon fiber composite, and ball mill at 72℃ for 55 minutes to obtain concrete;

[0072] The concrete, by weight, comprises the following components: 55 parts solid waste-based composite cementitious material, 12 parts fly ash, 8 parts gypsum, 1.5 parts quicklime, 8 parts cement, and 4 parts silica-carbon fiber composite.

[0073] Step 2: Preparation of copper-plated silicon dioxide:

[0074] Take 15 mL of 0.3 mol / L copper sulfate solution and 35 mL of 0.7 mol / L sulfuric acid solution, stir well to obtain an electrolyte, add 2 mg / mL of silica, stir well, and perform pulse electrophoretic deposition treatment for 30 min. The cathode is a copper alloy and the anode is pure titanium. After pulse electrophoretic deposition, wash and dry to obtain copper-plated silica.

[0075] Step 3: Preparation of silica-carbon fiber composite:

[0076] Take 25g of carbon fiber and 1000mL of deionized water, sonicate for 60min, add 0.5g of dopamine, stir for 32min, add 1.5g of tris(hydroxymethyl)aminomethane buffer, add hydrochloric acid to adjust the pH to 8.3, stir at 28℃ for 22h, add 6g of copper-plated silica, stir at 28℃ for 23h, centrifuge, wash and dry to obtain silica-carbon fiber composite.

[0077] Comparative Example 3: The copper-plated silica was not combined with the modified carbon fiber; all other aspects were the same as in Example 1.

[0078] Step 1: Solid waste-based composite cementitious material:

[0079] Take 38g of carbide slag, 28g of slag powder, and 4g of silica fume, grind them to obtain a cementitious material; take the cementitious material, add 1000mL of toluene, ultrasonically disperse it, add 15g of γ-aminopropyltriethoxysilane, stir for 21h, centrifuge, wash, and dry to obtain a solid waste-based composite cementitious material.

[0080] Take solid waste-based composite cementitious material, add gypsum, quicklime, cement, fly ash, copper-plated silica, and modified carbon fiber, and ball mill at 72℃ for 55 minutes to obtain concrete;

[0081] The concrete, by weight, comprises the following components: 55 parts solid waste-based composite cementitious material, 12 parts fly ash, 8 parts gypsum, 1.5 parts quicklime, 8 parts cement, 1 part copper-plated silica, and 3 parts modified carbon fiber.

[0082] Step 2: Preparation of copper-plated silicon dioxide:

[0083] Take 15 mL of 0.3 mol / L copper sulfate solution and 35 mL of 0.7 mol / L sulfuric acid solution, stir well to obtain an electrolyte, add 2 mg / mL of silica, stir well, and perform pulse electrophoretic deposition treatment for 30 min. The cathode is a copper alloy and the anode is pure titanium. After pulse electrophoretic deposition, wash and dry to obtain copper-plated silica.

[0084] Step 3: Preparation of modified carbon fiber:

[0085] Take 5g of carbon fiber and 300mL of toluene, disperse them by ultrasonication, purge with nitrogen, add 8.5g of γ-aminopropyltriethoxysilane, heat to 102℃, stir for 21h, cool, centrifuge, wash and dry to obtain the pretreated carbon fiber;

[0086] Take the pretreated carbon fiber and 300 mL of methanol, disperse them ultrasonically, add 1 g of methyl acrylate, heat to 52 °C, stir for 12 h, add 1 g of ethylenediamine, stir, centrifuge, wash and dry; add 300 mL of dimethyl sulfoxide, stir for 23 min, heat to 72 °C, add 7.2 g of poly(ethylene glycol) methacrylate and 0.1 g of lithium chloride, stir for 24 h, centrifuge, wash and dry to obtain modified carbon fiber.

[0087] Example 4: No treatment is applied to the cementitious material; everything else is the same as in Example 1.

[0088] Step 1: Preparation of solid waste-based composite cementitious materials:

[0089] Take 38g of carbide slag, 28g of slag powder, and 4g of silica fume, grind them to obtain a cementitious material; take the cementitious material, add gypsum, quicklime, cement, fly ash, and silica-carbon fiber composite, and ball mill at 72℃ for 55min to obtain a solid waste-based composite cementitious material.

[0090] The solid waste-based composite cementitious material, by weight, comprises the following components: 55 parts cementitious material, 12 parts fly ash, 8 parts gypsum, 1.5 parts quicklime, 8 parts cement, and 4 parts silica-carbon fiber composite.

[0091] Step 2: Preparation of copper-plated silicon dioxide:

[0092] Take 15 mL of 0.3 mol / L copper sulfate solution and 35 mL of 0.7 mol / L sulfuric acid solution, stir well to obtain an electrolyte, add 2 mg / mL of silica, stir well, and perform pulse electrophoretic deposition treatment for 30 min. The cathode is a copper alloy and the anode is pure titanium. After pulse electrophoretic deposition, wash and dry to obtain copper-plated silica.

[0093] Step 3: Preparation of modified carbon fiber:

[0094] Take 5g of carbon fiber and 300mL of toluene, disperse them by ultrasonication, purge with nitrogen, add 8.5g of γ-aminopropyltriethoxysilane, heat to 102℃, stir for 21h, cool, centrifuge, wash and dry to obtain the pretreated carbon fiber;

[0095] Take the pretreated carbon fiber and 300 mL of methanol, disperse them ultrasonically, add 1 g of methyl acrylate, heat to 52 °C, stir for 12 h, add 1 g of ethylenediamine, stir, centrifuge, wash and dry; add 300 mL of dimethyl sulfoxide, stir for 23 min, heat to 72 °C, add 7.2 g of poly(ethylene glycol) methacrylate and 0.1 g of lithium chloride, stir for 24 h, centrifuge, wash and dry to obtain modified carbon fiber;

[0096] Step 4: Preparation of silica-carbon fiber composite:

[0097] Take 25g of modified carbon fiber and 1000mL of deionized water, sonicate for 60min, add 0.5g of dopamine, stir for 32min, add 1.5g of tris(hydroxymethyl)aminomethane buffer, add hydrochloric acid to adjust the pH to 8.3, stir at 28℃ for 22h, add 6g of copper-plated silica, stir at 28℃ for 23h, centrifuge, wash and dry to obtain silica-carbon fiber composite.

[0098] experiment:

[0099] The concrete prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was used to prepare neat cement paste specimens of 40mm × 40mm × 40mm at a water-cement ratio of 0.5. These specimens were cured under standard curing conditions, and their 28-day compressive strength was tested. The data obtained are shown in Table 1 below.

[0100] Table 1

[0101]

[0102] Conclusion: The data comparison in the table shows that in Comparative Example 1, without copper plating of silica, the concrete strength decreased. In Comparative Example 2, without modification of carbon fiber, the compatibility between carbon fiber and concrete matrix was poor, resulting in decreased compressive strength. In Comparative Example 3, without combining copper-plated silica with modified carbon fiber, the strength of the concrete matrix decreased. In Example 4, without treatment of the cementitious material, the filler had poor compatibility with the concrete matrix, resulting in decreased compressive strength. Examples 1 to 3 of this invention involved copper plating of silica, which was then added to concrete, thus enhancing the concrete strength. By using methyl acrylate and poly(ethylene glycol) methacrylate to modify carbon fiber, the hydrophilicity of the modified carbon fiber was enhanced, improving its compatibility with the concrete matrix, thereby reducing the porosity of the concrete matrix and enhancing its strength. In Examples 1 to 3 of this invention, copper-plated silica is combined with modified carbon fiber. γ-aminopropyltriethoxysilane is also used to modify carbide slag, fly ash, and silica fume to improve the dispersibility of the copper-plated silica. This results in better compatibility of the silica-carbon fiber composite in concrete matrix and enhances the strength of the concrete matrix.

[0103] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing concrete, characterized in that: The concrete preparation method is as follows: take solid waste-based composite cementitious material, add gypsum, quicklime, cement, fly ash, and silica-carbon fiber composite, and ball mill at 70-75℃ for 50-60 minutes to obtain concrete; The preparation method of the silica-carbon fiber composite is as follows: take modified carbon fiber and deionized water, ultrasonically disperse for 50-70 min, add dopamine, stir for 30-35 min, add tris(hydroxymethyl)aminomethane buffer, add hydrochloric acid, adjust the pH to 8.0-8.5, stir at 25-30℃ for 20-24 h, add copper-plated silica, stir at 25-30℃ for 22-24 h, centrifuge, wash, and dry to obtain the silica-carbon fiber composite; The modified carbon fiber is prepared as follows: pretreated carbon fiber and methanol are ultrasonically dispersed, methyl acrylate is added, the temperature is raised to 50-55℃, and the mixture is stirred for 10-14 hours. Ethylenediamine is added, and the mixture is stirred, centrifuged, washed, and dried. Dimethyl sulfoxide is added, and the mixture is stirred for 20-25 minutes. The temperature is raised to 70-75℃, poly(ethylene glycol) methacrylate and lithium chloride are added, and the mixture is stirred for 22-26 hours. The mixture is centrifuged, washed, and dried to obtain the modified carbon fiber. The method for preparing the pretreated carbon fiber is as follows: take carbon fiber and toluene, disperse them ultrasonically, pass nitrogen gas, add γ-aminopropyltriethoxysilane, heat to 100-105℃, stir for 20-22h, cool, centrifuge, wash and dry to obtain the pretreated carbon fiber. The preparation method of the copper-plated silicon dioxide is as follows: take copper sulfate solution and sulfuric acid solution, stir evenly to obtain electrolyte, add silicon dioxide, stir evenly, and perform pulse electrophoretic deposition treatment for 30-40 minutes. The cathode is copper alloy and the anode is pure titanium. After the pulse electrophoretic deposition is completed, wash and dry to obtain copper-plated silicon dioxide.

2. The method for preparing concrete according to claim 1, characterized in that: The concrete, by weight, comprises the following components: 50-58 parts of solid waste-based composite cementitious material, 10-15 parts of fly ash, 6-10 parts of gypsum, 1-2 parts of quicklime, 5-10 parts of cement, and 3-5 parts of silica-carbon fiber composite.

3. The method for preparing concrete according to claim 1, characterized in that: The mass ratio of the carbon fiber to γ-aminopropyltriethoxysilane is (5-6):8.

5.

4. Concrete prepared by the concrete preparation method according to any one of claims 2-3.

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