Gold tailings-based alkali-activated ultra-high performance concrete and preparation method thereof

Abstract

The application relates to the technical field of concrete, in particular to gold tailing-based alkali-activated ultra-high performance concrete and a preparation method thereof; the concrete comprises concrete base material, water and fibers; the concrete base material is composed of the following raw materials in parts by weight: 900-950 parts of alkali-activated cementitious materials, 200-220 parts of silica fume, 83-90 parts of machine-made sand, 20-30 parts of gold tailing sand (particle size > 100 mesh) and 4-6 parts of water reducing agent; the mass ratio of the water to the cementitious material is 5.56:1.00; the content of the fibers ranges from 1.0% to 3.0% (volume content); the prepared ultra-high performance concrete has super-high strength, super-long durability and outstanding tensile toughness, and is good in mechanical properties and construction performance. In addition, in the application, the fine part (particle size < 100 mesh) of the gold tailing is used as the raw material of the alkali-activated cementitious material, and the coarse part (particle size > 100 mesh) of the gold tailing is used as the fine aggregate of the concrete, so that the solid waste material is recycled, the comprehensive utilization rate of the tailing is improved, and the green and low-carbon development concept of the building material is met.

Description

Technical Field

[0001] This invention relates to the field of concrete technology, and in particular to a gold tailings-based alkali-activated ultra-high performance concrete and its preparation method. Background Technology

[0002] Concrete is a general term for composite materials made by mixing gelling materials, aggregates, and water in appropriate proportions and allowing them to harden over a certain period of time. It is the most widely used man-made building material in the world. Classified by application, it includes structural concrete, road concrete, waterproof concrete, heat-resistant concrete, expansive concrete, and radiation-resistant concrete. Concrete has high hardness, a wide range of raw material sources, and low cost, making it widely used in buildings, highways, military engineering, nuclear power plants, and other structures.

[0003] Patent application CN201510475964.6 discloses a feldspar waste concrete and its preparation method. The raw materials consist of feldspar waste, clay, cement, phenolic fiber, polyvinylidene chloride fiber, water, and admixtures. The admixtures are composed of carbonyl pyroaldehyde high-efficiency water-reducing agent, sodium aluminate-based quick-setting agent, citric acid-chitosan binder, and diatomaceous earth powder. While the concrete prepared by this patent has advantages such as good frost resistance, fire resistance, and water resistance, its mechanical strength is relatively insufficient, which to some extent limits its material properties and application range. Therefore, this invention provides a gold tailings-based alkali-activated ultra-high performance concrete and its preparation method to solve the aforementioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide an alkali-activated ultra-high performance concrete based on gold tailings and its preparation method. The prepared ultra-high performance concrete exhibits ultra-high strength, ultra-long durability, and outstanding tensile toughness, with excellent mechanical and construction properties. Furthermore, in this invention, the finer fraction of the gold tailings (particle size <100 mesh) is used as a raw material for alkali-activated cementitious materials, while the coarser fraction (particle size >100 mesh) is used as fine aggregate in the concrete. This achieves resource utilization of solid waste materials, improves the comprehensive utilization rate of tailings, and aligns with the green and low-carbon development concept of building materials.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A gold tailings-based alkali-activated ultra-high performance concrete comprises a concrete base material, a fiber reinforcing agent, and water; characterized in that the concrete base material is composed of the following raw materials in parts by weight: 900-950 parts alkali-activated cementitious material, 200-220 parts silica fume, 83-90 parts manufactured sand, 20-30 parts gold tailings sand, and 4-6 parts water-reducing agent, wherein the particle size of the gold tailings sand is >100 mesh; the mass ratio of water to cementitious material is 5.56:1.00; and the volumetric dosage of the fiber reinforcing agent ranges from 1.0% to 3.0%.

[0007] Furthermore, the method for preparing the fiber reinforcing agent is as follows:

[0008] Step S1: Add tetraethoxysilane to an ethanol aqueous solution with a concentration of 60-75 wt% at a dosage ratio of 0.3-0.4 g / mL, and mix thoroughly.

[0009] Step S2: Adjust the pH of the solution obtained in step S1 to 3.5–4.5 using dilute hydrochloric acid;

[0010] Step S3: Add 0.2 to 0.3 times the mass of modified steel fiber and 0.1 to 0.2 times the mass of modified glass fiber to the solution described in step S2, and mix thoroughly.

[0011] Step S4: Stir the reaction at 40–50°C for 8–12 hours;

[0012] Step S5: After the reaction is complete, filter the components obtained in step S4 to obtain solid filter media;

[0013] Step S6: Transfer the obtained solid filter material into a drying device and dry it at a temperature of 50-70°C for 3-5 hours to obtain a fiber reinforcing agent.

[0014] Furthermore, the method for preparing the modified steel fiber includes the following steps:

[0015] The first step involves immersing the steel fibers in a 20-25 wt% sodium hydroxide aqueous solution at a temperature of 40-60°C for 40-60 minutes. After immersion, the steel fibers are removed and washed 2-3 times each with anhydrous ethanol and deionized water, followed by drying. The resulting pretreated steel fibers are then stored for future use. The steel fibers have a tensile strength ≥2500 MPa, a length of 12-16 mm, and a diameter of 0.18-0.22 mm.

[0016] The second step involves adding 5-8% N-(β-aminoethyl)-γ-aminopropyltriethoxysilane by volume to an 80-90 wt% ethanol aqueous solution. After stirring evenly, the pH of the mixture is adjusted to 4.5-5.8 with glacial acetic acid. Then, the mixture is stirred and hydrolyzed at 30-40°C for 5-8 hours. The resulting silane hydrolysate is stored for later use.

[0017] The third step involves adding the pretreated steel fibers to the silane hydrolysate according to a solid-liquid ratio of 0.05–0.1 g / mL, dispersing them evenly, and reacting for 30–50 minutes. After the reaction is complete, the steel fibers are filtered out and transferred to a drying device, where they are dried at 90–110°C for 2–4 hours. The resulting product is the modified steel fiber.

[0018] Furthermore, the method for preparing the modified glass fiber includes the following steps:

[0019] Step 1: Add glass fiber to 25-30 wt% hydrogen peroxide at a solid-liquid ratio of 0.02-0.05 g / mL, mix and stir evenly, then heat to 105-110℃ and keep at this temperature for 3-5 hours; after the reaction is complete, filter out the glass fiber and dry it.

[0020] Step 2: Disperse the dried glass fiber evenly in acetone at a solid-liquid ratio of 0.05-0.1 g / mL, add 3-aminopropyltriethoxysilane at a mass of 3-6 times that of the glass fiber, mix evenly, and react at 80-85℃ for 5-8 hours; after the reaction is completed, filter and dry the product components in sequence, and store the obtained pretreated glass fiber for later use.

[0021] Step 3: Disperse the pretreated glass fiber evenly in N,N-dimethylformamide at a solid-liquid ratio of 0.03-0.08 g / mL, then add phthalic anhydride (1-2 times the mass of the pretreated glass fiber) and tetramethylolmethane (1.2-1.6 times the mass of the pretreated glass fiber), mix and stir evenly, and then react at a constant temperature of 110-130℃ for 6-10 h.

[0022] Step 4: Add diethylenetriamine at a mass of 3 to 6 times that of phthalic anhydride to the product obtained in Step 3, disperse it evenly, and react it at a constant temperature of 100 to 120°C for 5 to 10 hours. After the reaction is complete, filter, wash and dry the reaction product in sequence to obtain the modified glass fiber.

[0023] Furthermore, the fine aggregate is any one of quartz sand, river sand, and manufactured sand, with a particle size of 0.08 to 3 mm, a fineness modulus of 2.6 to 2.8, a moisture content of ≤0.1%, and a mud content of ≤0.5%; the fine aggregate also includes the coarser part of gold tailings, gold tailings sand, with a particle size of 0.2 to 0.4 mm.

[0024] Furthermore, the alkaline activator is a compound of sodium hydroxide and water glass in a mass ratio of 1:1 to 1:3.5.

[0025] Furthermore, the water-reducing agent is selected from any one of polycarboxylate-based high-performance water-reducing agents, aminosulfonate-based high-efficiency water-reducing agents, and naphthalenesulfonate water-reducing agents.

[0026] Furthermore, the air-entraining agent is selected from any one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and rosin-based air-entraining agents.

[0027] A method for preparing gold tailings-based alkali-activated ultra-high performance concrete includes the following steps:

[0028] Step a: Accurately weigh each raw material of the concrete base material;

[0029] Step b: Add all the weighed raw materials of the concrete base material, except for the fiber reinforcing agent, into the mixing equipment and mix them evenly;

[0030] Step c: Add the fiber reinforcing agent and water to the product from step b and stir until homogeneous;

[0031] Step d: After steam curing for 48 hours or natural curing for 28 days, the gold tailings-based alkali-activated ultra-high performance concrete product is obtained.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] The present invention first pre-treats the steel fibers to remove oil and stains from their surface, and then puts them into a silane hydrolysate. After being evenly dispersed, the fibers react with N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and the two are finally connected by chemical bonds to modify the surface properties of the steel fibers.

[0034] Furthermore, in this invention, glass fibers are immersed in hydrogen peroxide to hydroxylate their surface. These fibers are then dispersed in acetone with the addition of 3-aminopropyltriethoxysilane. After thorough mixing, a heat-preserving reaction is carried out, ultimately resulting in the grafting of 3-aminopropyltriethoxysilane onto the surface of the glass fibers, thus obtaining pretreated glass fibers. The pretreated glass fibers are then uniformly dispersed in N,N-dimethylformamide, with the subsequent addition of phthalic anhydride, tetramethylolmethane, and diethylenetriamine. This process grafts a significant amount of macromolecular organic matter onto the glass fiber surface, achieving hyperbranching and expanding the three-dimensional structure of the glass fibers, ultimately yielding modified glass fibers.

[0035] The modified steel fibers and modified glass fibers were added to an ethanol-water solution containing tetraethoxysilane, uniformly dispersed, and then stirred at a constant temperature. This resulted in the deposition of a dense layer of nano-oxide on the surfaces of the modified steel and glass fibers, effectively increasing their surface roughness and thus expanding their contact area with the concrete matrix. This further enhanced the friction between the fibers and the concrete matrix, significantly improving the tensile properties of the concrete and effectively increasing its toughness. Furthermore, in this invention, the finer fraction of the gold tailings (particle size <100 mesh) is used as a raw material for alkali-activated cementitious materials, while the coarser fraction (particle size >100 mesh) is used as fine aggregate in concrete. This achieves the resource utilization of solid waste materials, improves the comprehensive utilization rate of tailings, and aligns with the green and low-carbon development concept of building materials. Detailed Implementation

[0036] 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.

[0037] Example 1

[0038] A gold tailings-based alkali-activated ultra-high performance concrete includes a concrete matrix, water, and a fiber reinforcing agent. The concrete matrix is ​​composed of the following raw materials in parts by weight: 900 parts alkali-activated cementitious material, 200 parts silica fume, 85 parts manufactured sand, 25 parts gold tailings sand, and 4 parts polycarboxylate-based high-performance water-reducing agent. The mass ratio of water to concrete matrix raw materials is 5.56:1.00, and the volumetric dosage of the fiber reinforcing agent is 1.0%.

[0039] The fine aggregate consists of manufactured sand and gold tailings sand. The manufactured sand has a particle size of 0.08 mm, a fineness modulus of 2.6, a moisture content of 0.1%, and a mud content of 0.5%. The gold tailings sand has a particle size of 0.2–0.4 mm. The alkali activator is a mixture of sodium hydroxide and water glass in a 1:1 mass ratio. The polycarboxylate superplasticizer is PC-1022 polyether polycarboxylate superplasticizer purchased from Suzhou Xingbang Chemical Building Materials Co., Ltd.

[0040] The fiber reinforcing agent is prepared as follows: Tetraethoxysilane is added to a 60wt% ethanol aqueous solution at a dosage ratio of 0.3g / mL. After mixing evenly, the pH is adjusted to 3.5 with dilute hydrochloric acid. Then, 20% modified steel fiber and 10% modified glass fiber by mass fraction are added to the resulting mixture. After being evenly dispersed, the mixture is kept at 40℃ and stirred for 8 hours. After the reaction is completed, the product components are filtered, and the resulting solid filter material is transferred to a drying device and dried at 50℃ for 3 hours. After drying, the resulting solid material is the fiber reinforcing agent.

[0041] The preparation method of modified steel fibers includes the following steps:

[0042] The first step involves immersing the steel fibers in a 20 wt% sodium hydroxide aqueous solution at 40°C for 40 minutes. After immersion, the steel fibers are removed and washed twice each with anhydrous ethanol and deionized water, and then dried. The resulting pretreated steel fibers are stored for later use. The steel fibers have a tensile strength of 2500 MPa, a length of 12 mm, and a diameter of 0.18 mm.

[0043] The second step involves adding 5% by volume of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane to an 80wt% ethanol aqueous solution, stirring until homogeneous, adjusting the pH of the mixture to 4.5 with glacial acetic acid, and then hydrolyzing at 30°C for 5 hours. The resulting silane hydrolysate is then stored for later use.

[0044] The third step involves adding the pretreated steel fibers to the silane hydrolysate at a solid-liquid ratio of 0.05 g / mL, dispersing them evenly, and reacting for 30 minutes. After the reaction is complete, the steel fibers are filtered out and transferred to a drying device, where they are dried at 90°C for 2 hours. The resulting product is the modified steel fiber.

[0045] The preparation method of modified glass fiber includes the following steps:

[0046] Step 1: Add glass fiber to 25wt% hydrogen peroxide at a solid-liquid ratio of 0.02g / mL, mix and stir evenly, then heat to 105℃ and keep at this temperature for 3 hours; after the reaction is complete, filter out the glass fiber and dry it; the glass fiber has a length of 10μm and a diameter of 8μm.

[0047] Step 2: Disperse the dried glass fiber evenly in acetone at a solid-liquid ratio of 0.05 g / mL, add 3-aminopropyltriethoxysilane (3 times the mass of the glass fiber), mix evenly, and react at 80°C for 5 hours. After the reaction is complete, filter and dry the product components in sequence, and store the pretreated glass fiber for later use.

[0048] Step 3: Disperse the pretreated glass fiber uniformly in N,N-dimethylformamide at a solid-liquid ratio of 0.03 g / mL. Then add phthalic anhydride (1 times the mass of the pretreated glass fiber) and tetramethylolpropane (1.2 times the mass of the pretreated glass fiber). Mix and stir evenly, and then keep the mixture at 110°C for 6 hours. After the reaction is complete, add diethylenetriamine (3 times the mass of the phthalic anhydride) to the product component, disperse it evenly, and keep the mixture at 100°C for 5 hours. After the reaction is complete, filter, wash, and dry the reaction product in sequence to obtain the modified glass fiber.

[0049] A method for preparing gold tailings-based alkali-activated ultra-high performance concrete includes the following steps: accurately weighing each raw material, modifying the fiber with a fiber reinforcing agent, then putting each raw material of the concrete base into a mixing device, stirring evenly, and then adding the modified fiber and water; after mixing evenly, injecting the resulting slurry into a mold for molding, and then steam curing for 48 hours or natural curing for 28 days to obtain the finished gold tailings-based alkali-activated ultra-high performance concrete.

[0050] Example 2

[0051] The preparation method of gold tailings-based alkali-activated ultra-high performance concrete provided in this embodiment is basically the same as that in Example 1, except that the material composition of the concrete and the preparation method of the fiber reinforcing agent are not exactly the same. The specific composition of the concrete product and the preparation method of the fiber reinforcing agent in this embodiment are as follows:

[0052] A gold tailings-based alkali-activated ultra-high performance concrete includes a concrete matrix, water, and fibers. The concrete matrix is ​​composed of the following raw materials in parts by weight: 950 parts alkali-activated cementitious material, 220 parts silica fume, 90 parts manufactured sand, 20 parts gold tailings sand, and 4 parts polycarboxylate-based high-performance water-reducing agent. The mass ratio of water to the concrete matrix raw materials is 5.56:1.00, and the volumetric dosage of the fiber reinforcing agent is 1.0%.

[0053] The fine aggregate consists of manufactured sand and gold tailings sand. The manufactured sand has a particle size of 0.08 mm, a fineness modulus of 2.6, a moisture content of 0.1%, and a mud content of 0.5%. The gold tailings sand has a particle size of 0.2–0.4 mm. The alkali activator is a mixture of sodium hydroxide and water glass in a mass ratio of 1:3.5. The polycarboxylate superplasticizer is PC-1022 polyether polycarboxylate superplasticizer purchased from Suzhou Xingbang Chemical Building Materials Co., Ltd.

[0054] The fiber reinforcing agent is prepared as follows: Tetraethoxysilane is added to a 70wt% ethanol aqueous solution at a dosage ratio of 0.35g / mL. After mixing evenly, the pH is adjusted to 4.0 with dilute hydrochloric acid. Then, 25% modified steel fiber and 15% modified glass fiber by mass fraction are added to the resulting mixture. After being evenly dispersed, the mixture is kept at 45℃ and stirred for 10h. After the reaction is completed, the product components are filtered, and the resulting solid filter material is transferred to a drying device and dried at 60℃ for 4h. After drying, the resulting solid material is the fiber reinforcing agent.

[0055] The preparation method of modified steel fibers includes the following steps:

[0056] The first step involves immersing the steel fibers in a 20 wt% sodium hydroxide aqueous solution at 50°C for 50 minutes. After immersion, the steel fibers are removed and washed three times each with anhydrous ethanol and deionized water, and then dried. The resulting pretreated steel fibers are stored for later use. The steel fibers have a tensile strength of 2500 MPa, a length of 12 mm, and a diameter of 0.18 mm.

[0057] The second step involves adding 6% by volume of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane to an 85wt% ethanol aqueous solution, stirring until homogeneous, adjusting the pH of the mixture to 5.0 with glacial acetic acid, and then hydrolyzing at 35°C for 6 hours. The resulting silane hydrolysate is then stored for later use.

[0058] The third step involves adding the pretreated steel fibers to the silane hydrolysate at a solid-liquid ratio of 0.08 g / mL, dispersing them evenly, and reacting for 40 minutes. After the reaction is complete, the steel fibers are filtered out and transferred to a drying device, where they are dried at 100°C for 3 hours. The resulting product is the modified steel fiber.

[0059] The preparation method of modified glass fiber includes the following steps:

[0060] Step 1: Add glass fiber to 30wt% hydrogen peroxide at a solid-liquid ratio of 0.05g / mL, mix and stir evenly, then heat to 110℃ and keep at this temperature for 4 hours; after the reaction is complete, filter out the glass fiber and dry it; the glass fiber has a length of 10μm and a diameter of 8μm.

[0061] Step 2: Disperse the dried glass fiber evenly in acetone at a solid-liquid ratio of 0.06 g / mL, add 3-aminopropyltriethoxysilane with a mass of 5 times that of the glass fiber, mix evenly, and react at 80°C for 6 hours; after the reaction is complete, filter and dry the product components in sequence, and store the obtained pretreated glass fiber for later use.

[0062] Step 3: Disperse the pretreated glass fiber uniformly in N,N-dimethylformamide at a solid-liquid ratio of 0.05 g / mL. Then add phthalic anhydride (1.5 times the mass of the pretreated glass fiber) and tetramethylolpropane (1.4 times the mass of the pretreated glass fiber). Mix and stir evenly, and then keep the mixture at 120°C for 8 hours. After the reaction is complete, add diethylenetriamine (5 times the mass of the phthalic anhydride) to the product component, disperse it evenly, and keep the mixture at 110°C for 8 hours. After the reaction is complete, filter, wash, and dry the reaction product in sequence to obtain the modified glass fiber.

[0063] Example 3

[0064] The preparation method of gold tailings-based alkali-activated ultra-high performance concrete provided in this embodiment is basically the same as that in Example 1, except that the material composition of the concrete product and the preparation method of the fiber reinforcing agent are not exactly the same. The specific composition of the concrete product and the preparation method of the fiber reinforcing agent in this embodiment are as follows:

[0065] A gold tailings-based alkali-activated ultra-high performance concrete includes a concrete matrix, water, and a fiber reinforcing agent. The concrete matrix is ​​composed of the following raw materials in parts by weight: 1000 parts alkali-activated cementitious material, 200 parts silica fume, 90 parts manufactured sand, 20 parts gold tailings sand, and 4 parts polycarboxylate-based high-performance water-reducing agent. The mass ratio of water to the concrete matrix raw materials is 5.88:1.00, and the volumetric dosage of the fiber reinforcing agent is 1.0%.

[0066] The fine aggregate consists of manufactured sand and gold tailings sand. The manufactured sand has a particle size of 0.08 mm, a fineness modulus of 2.6, a moisture content of 0.1%, and a mud content of 0.5%. The gold tailings sand has a particle size of 0.2–0.4 mm. The alkali activator is a mixture of sodium hydroxide and water glass in a mass ratio of 1:3.5. The polycarboxylate superplasticizer is PC-1022 polyether polycarboxylate superplasticizer purchased from Suzhou Xingbang Chemical Building Materials Co., Ltd.

[0067] The fiber reinforcing agent is prepared as follows: Tetraethoxysilane is added to a 75wt% ethanol aqueous solution at a dosage ratio of 0.4g / mL. After mixing evenly, the pH is adjusted to 4.5 with dilute hydrochloric acid. Then, 0.3 times the mass of modified steel fiber and 0.2 times the mass of modified glass fiber are added to the resulting mixture. After even dispersion, the mixture is kept at 50℃ and stirred for 12 hours. After the reaction is completed, the product components are filtered, and the resulting solid filter material is transferred to a drying device and dried at 70℃ for 5 hours. After drying, the resulting solid material is the fiber reinforcing agent.

[0068] The preparation method of modified steel fibers includes the following steps:

[0069] The first step involves immersing the steel fibers in a 25 wt% sodium hydroxide aqueous solution at 60°C for 60 minutes. After immersion, the steel fibers are removed and washed three times each with anhydrous ethanol and deionized water, and then dried. The resulting pretreated steel fibers are stored for later use. The steel fibers have a tensile strength of 2500 MPa, a length of 12 mm, and a diameter of 0.18 mm.

[0070] The second step involves adding 8% by volume of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane to a 90wt% ethanol aqueous solution, stirring until homogeneous, adjusting the pH of the mixture to 5.8 with glacial acetic acid, and then hydrolyzing at 40℃ for 8 hours. The resulting silane hydrolysate is then stored for later use.

[0071] The third step involves adding the pretreated steel fibers to the silane hydrolysate at a solid-liquid ratio of 0.1 g / mL, dispersing them evenly, and reacting for 50 minutes. After the reaction is complete, the steel fibers are filtered out and transferred to a drying device, where they are dried at 110°C for 4 hours. The resulting product is the modified steel fiber.

[0072] The preparation method of modified glass fiber includes the following steps:

[0073] Step 1: Add glass fiber to 30wt% hydrogen peroxide at a solid-liquid ratio of 0.05g / mL, mix and stir evenly, then heat to 110℃ and keep at this temperature for 5 hours; after the reaction is complete, filter out the glass fiber and dry it; the glass fiber has a length of 10μm and a diameter of 8μm.

[0074] Step 2: Disperse the dried glass fiber evenly in acetone at a solid-liquid ratio of 0.1 g / mL, add 3-aminopropyltriethoxysilane with a mass of 6 times that of the glass fiber, mix evenly, and react at 85°C for 8 hours; after the reaction is complete, filter and dry the product components in sequence, and store the obtained pretreated glass fiber for later use.

[0075] Step 3: Disperse the pretreated glass fiber uniformly in N,N-dimethylformamide at a solid-liquid ratio of 0.08 g / mL. Then add phthalic anhydride (2 times the mass of the pretreated glass fiber) and tetramethylolpropane (1.6 times the mass of the pretreated glass fiber). Mix and stir evenly, and then keep the mixture at 130°C for 10 h. After the reaction is complete, add diethylenetriamine (6 times the mass of the phthalic anhydride) to the product component, disperse it evenly, and keep the mixture at 120°C for 10 h. After the reaction is complete, filter, wash, and dry the reaction product in sequence to obtain the modified glass fiber.

[0076] Comparative Example 1: The main difference between this comparative example and Example 1 is that an equal amount of fiber mixture is used in this comparative example instead of the fiber reinforcing agent in Example 1; wherein, the fiber mixture is composed of modified steel fiber and modified glass fiber, and the content of modified steel fiber and modified glass fiber in the fiber mixture is equal to that of the fiber reinforcing agent; that is, no ethanol solution containing tetraethoxysilane is used to treat the modified steel fiber and modified glass fiber in this comparative example.

[0077] Comparative Example 2: The main difference between this comparative example and Comparative Example 1 is that: in this comparative example, an equal amount of steel fiber is used to replace the modified steel fiber, and an equal amount of glass fiber is used to replace the modified glass fiber; that is, the total amount of steel fiber and glass fiber used in this comparative example is equal to the total amount of modified steel fiber and modified glass fiber used in Comparative Example 1.

[0078] Performance testing

[0079] The relevant properties of the gold tailings-based alkali-activated ultra-high performance concrete samples provided in Examples 1-3 and Comparative Examples 1-2 were tested as follows, and the test data are recorded in the table below:

[0080]

[0081] By comparing and analyzing the relevant data in the table, it can be seen that the prepared gold tailings-based ultra-high performance concrete possesses extremely high compressive and flexural strengths, meeting the relevant specifications, while also exhibiting excellent durability and flexural toughness, demonstrating outstanding performance in all aspects. Furthermore, this invention uses gold mine tailings as the raw material for preparing ultra-high performance concrete, realizing the resource utilization of solid waste materials, improving the comprehensive utilization rate of tailings, and conforming to the green and low-carbon development concept of building materials. Therefore, it is evident that the gold tailings-based alkali-activated ultra-high performance concrete and its preparation method provided by this invention have broader market prospects and practical engineering value.

[0082] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A gold tailings based alkali-activated ultra-high performance concrete comprising a concrete base, a fiber reinforcement agent, and water; characterized in that, The concrete base material is composed of 900-950 parts of alkali-activated cementitious material, 200-220 parts of silica fume, 83-90 parts of machine-made sand, 20-30 parts of gold tailings sand, and 4-6 parts of water reducing agent, the particle size of the gold tailings sand is >100 mesh; the mass ratio of water to alkali-activated cementitious material is 5.56:1.00; the volume content of the fiber reinforcing agent ranges from 1.0 to 3.0%; The preparation method of the fiber reinforcing agent is as follows: Step S1, tetraethoxysilane is put into an ethanol aqueous solution with a concentration of 60-75 wt% at a dosage ratio of 0.3-0.4 g / mL, and mixed uniformly; Step S2, the solution obtained in step S1 is adjusted to a pH of 3.5-4.5 with dilute hydrochloric acid; Step S3, modified steel fibers with a mass of 0.2-0.3 times that of the solution obtained in step S2, and modified glass fibers with a mass of 0.1-0.2 times that of the solution obtained in step S2 are added to the solution, and mixed uniformly; Step S4, stirring is carried out at a temperature of 40-50℃ for 8-12h; Step S5, after the reaction is completed, the components obtained in step S4 are filtered to obtain a solid filter material; Step S6, the obtained solid filter material is transferred into a drying device, and dried at a temperature of 50-70℃ for 3-5h to obtain the fiber reinforcing agent; The preparation method of the modified steel fiber comprises the following steps: First step, the steel fiber is soaked in a sodium hydroxide aqueous solution with a temperature of 40-60℃ and a concentration of 20-25 wt% for 40-60 min; after soaking, the steel fiber is taken out and washed with anhydrous ethanol and deionized water for 2-3 times respectively, and then the steel fiber is dried and treated, and the obtained pretreated steel fiber is stored for use; Second step, N-(β-aminoethyl)-γ-aminopropyl triethoxysilane with a volume content of 5-8% is added to an 80-90 wt% ethanol aqueous solution, and after stirring uniformly, the pH value of the mixture is adjusted to 4.5-5.8 with glacial acetic acid, and then the mixture is stirred at a temperature of 30-40℃ for 5-8h, and the obtained silane hydrolysis solution is stored for use; Third step, the pretreated steel fiber is put into the silane hydrolysis solution at a solid-liquid ratio of 0.05-0.1 g / mL, and after uniform dispersion, the mixture is reacted for 30-50 min; Fourth step, the product obtained in the third step is filtered, and the solid product obtained by filtration is transferred into a drying device and dried at a temperature of 90-110℃ for 2-4h, and the obtained product is the modified steel fiber; The preparation method of the modified glass fiber comprises the following steps: Step one, glass fiber is put into 25-30 wt% hydrogen peroxide at a solid-liquid ratio of 0.02-0.05 g / mL, and after stirring and mixing uniformly, the temperature is raised to 105-110℃, and the mixture is reacted at this temperature for 3-5h; after the reaction is completed, the glass fiber is filtered and dried. Step two, the dry glass fiber is evenly dispersed in acetone with a solid-liquid ratio of 0.05-0.1 g / mL, 3-aminopropyl triethoxysilane is added with a mass of 3-6 times of the glass fiber, and the mixture is uniformly mixed and reacted at 80-85°C for 5-8h; after the reaction is completed, the components of the product are filtered and dried in sequence, and the obtained pretreated glass fiber is stored for use; Step three, the pretreated glass fiber is evenly dispersed in N,N-dimethylformamide with a solid-liquid ratio of 0.03-0.08 g / mL, then phthalic anhydride with a mass of 1-2 times of the pretreated glass fiber and tetramethylolmethane with a mass of 1.2-1.6 times of the pretreated glass fiber are added, the mixture is uniformly stirred and mixed, and then reacted at 110-130°C for 6-10h; Step four, diethylene triamine with a mass of 3-6 times of the phthalic anhydride is added to the product obtained in step three, and then uniformly dispersed and reacted at 100-120°C for 5-10h; after the reaction is completed, the reaction product is filtered, washed and dried in sequence, and the obtained is the modified glass fiber.

2. A gold tailings based alkali-activated ultra-high performance concrete according to claim 1, characterized in that: The water reducing agent is selected from any one of polycarboxylic acid high-performance water reducing agent, amino sulfonate high-efficiency water reducing agent and naphthalene sulfonate water reducing agent.

3. A method of preparing a gold tailings-based alkali-activated ultra-high performance concrete according to any one of claims 1 to 2, characterized in that, The method comprises the following steps: Step a, accurately weighing each raw material of the concrete base; Step b, putting the weighed raw materials of the concrete base into a mixing device and stirring uniformly; Step c, adding the fiber reinforcing agent and water to the product of step b and stirring uniformly; Step d, after steam curing for 48 hours or natural curing for 28 days, the gold tailing-based alkali-activated ultra-high performance concrete product is obtained.

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