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

Abstract

The invention 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 a concrete base material, water and fibers; the concrete base material is prepared from the following raw materials in parts by weight: 900-950 parts of alkali-activated cementing material, 200-220 parts of silica fume, 83-90 parts of machine-made sand and 20-30 parts of gold tailing sand (particle size gt; 100 meshes) and 4-6 parts of a water reducing agent; the mass ratio of the water to the cementing material is 5.56: 1.00; the mixing amount range of the fibers is 1.0-3.0% (volume mixing amount); the ultra-high performance concrete prepared by the invention has the advantages of ultra-high strength, ultra-long durability, outstanding tensile toughness and good mechanical and construction performance. In addition, the fine part of the gold tailings (the particle size is lt; 100 meshes) is used as a raw material of the alkali-activated cementing material, and the thicker part (particle size gt; the tailings (100 meshes) serve as fine aggregate of concrete, resource utilization of solid waste materials is achieved, the comprehensive utilization rate of the tailings is increased, and the green and low-carbon development concept of building materials is met.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to a gold tailings-based alkali-activated ultra-high performance concrete and a preparation method thereof. Background Art

[0002] Concrete is a composite material made of gel material, aggregate and water in appropriate proportions and hardened after a certain period of time. It is the world's most widely used artificial building material. According to its use, it is divided into structural concrete, road concrete, waterproof concrete, heat-resistant concrete, expansive concrete, radiation-proof concrete, etc. Concrete has high hardness, a wide range of raw materials, and low cost. It is widely used in buildings such as houses, roads, military projects, and nuclear power plants.

[0003] A feldspar waste concrete and a preparation method thereof are disclosed in the patent document with application number "CN201510475964.6", wherein the raw materials are: feldspar waste, clay, cement, phenolic fiber, polyvinylidene chloride fiber, water and admixtures, wherein the admixtures are composed of carbonyl pyroaldehyde high-efficiency water reducer, sodium aluminate quick-setting agent, citric acid-chitosan adhesive and diatomaceous earth powder. Although the concrete prepared in this patent document has the advantages of good frost resistance, fire resistance and water resistance, its mechanical strength is relatively insufficient, which limits its material properties and application range to a certain extent. Therefore, the present invention provides a gold tailings-based alkali-activated ultra-high performance concrete and a preparation method thereof to solve the above-mentioned technical problems. Summary of the invention

[0004] The object of the present invention is to provide a gold tailings-based alkali-activated ultra-high performance concrete and a preparation method thereof, wherein the prepared ultra-high performance concrete has ultra-high strength, ultra-long durability and outstanding tensile toughness, and has good mechanical and construction properties. In addition, in the present invention, the finer part of the gold tailings (particle size <100 mesh) is used as the raw material of the alkali-activated cementitious material, and the coarser part (particle size >100 mesh) is used as the fine aggregate of the concrete, which realizes the resource utilization of solid waste materials, improves the comprehensive utilization rate of tailings, and conforms to the green and low-carbon development concept of building materials.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A gold tailings-based alkali-activated ultra-high performance concrete comprises a concrete base material, a fiber reinforcement and water; the concrete base material is characterized in that the concrete base material is composed of the following raw materials in parts by weight: 900 to 950 parts of alkali-activated cementitious materials, 200 to 220 parts of silica fume, 83 to 90 parts of machine-made sand, 20 to 30 parts of gold tailings sand and 4 to 6 parts of water reducer, the particle size of the gold tailings sand is greater than 100 mesh; the mass ratio of the water to the cementitious materials is 5.56:1.00; and the volume content of the fiber reinforcement is in the range of 1.0 to 3.0%.

[0007] Furthermore, the preparation method of the fiber reinforcement is:

[0008] Step S1, adding tetraethoxysilane in a dosage ratio of 0.3-0.4 g / mL into an ethanol aqueous solution with a concentration of 60-75 wt%, and mixing evenly;

[0009] Step S2, adjusting the pH of the solution obtained in step S1 to 3.5-4.5 with dilute hydrochloric acid;

[0010] Step S3, adding 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 mixing them evenly;

[0011] Step S4, stirring the reaction at a temperature of 40 to 50° C. for 8 to 12 hours;

[0012] Step S5, after the reaction is completed, filtering the components obtained in step S4 to obtain a solid filter material;

[0013] Step S6, transferring the obtained solid filter material into a drying device, and drying it at a temperature of 50 to 70° C. for 3 to 5 hours to obtain a fiber reinforcement.

[0014] Furthermore, the preparation method of the modified steel fiber comprises the following steps:

[0015] The first step is to soak the steel fiber in a sodium hydroxide aqueous solution with a temperature of 40 to 60° C. and a concentration of 20 to 25 wt% for 40 to 60 minutes; after the soaking is completed, the steel fiber is fished out and washed with anhydrous ethanol and deionized water for 2 to 3 times respectively, and then dried, and the obtained pretreated steel fiber is stored and used for standby; wherein the tensile strength of the steel fiber is ≥2500 MPa, the length is 12 to 16 mm, and the diameter is 0.18 to 0.22 mm;

[0016] The second step is to add 5-8% by volume of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane to 80-90wt% ethanol aqueous solution, stir evenly, adjust the pH of the mixture to 4.5-5.8 with glacial acetic acid, and then stir and hydrolyze at 30-40°C for 5-8h, and store the obtained silane hydrolyzate for later use;

[0017] The third step is to put the pretreated steel fiber into the silane hydrolyzate according to the standard of solid-liquid ratio of 0.05-0.1g / mL, and react for 30-50min after uniform dispersion; after the reaction is completed, the steel fiber is filtered out and transferred to the drying equipment, and dried at 90-110°C for 2-4h to obtain the modified steel fiber.

[0018] Furthermore, the preparation method of the modified glass fiber comprises the following steps:

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

[0020] Step 2, uniformly dispersing the dried glass fiber in acetone at a solid-liquid ratio of 0.05 to 0.1 g / mL, adding 3-aminopropyltriethoxysilane in an amount 3 to 6 times the mass of the glass fiber, mixing evenly and reacting at a temperature of 80 to 85° C. for 5 to 8 hours; after the reaction is completed, filtering and drying the resultant components in turn, and storing the obtained pre-treated glass fiber for standby use;

[0021] Step 3, the pre-treated glass fiber is uniformly dispersed in N, N-dimethylformamide at a solid-liquid ratio of 0.03-0.08 g / mL, and then 1-2 times the mass of phthalic anhydride and 1.2-1.6 times the mass of tetramethylolmethane are added to the pre-treated glass fiber, and the mixture is stirred evenly and then reacted at a constant temperature of 110-130° C. for 6-10 hours;

[0022] Step 4: add diethylenetriamine in an amount 3 to 6 times the mass of phthalic anhydride to the product obtained in step 3, disperse the mixture evenly, and react at a constant temperature of 100 to 120° C. for 5 to 10 hours; after the reaction is completed, filter, wash and dry the reaction product in turn to obtain modified glass fiber.

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

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

[0025] Furthermore, the water reducer is selected from any one of a polycarboxylic acid-based high-performance water reducer, an aminosulfonate-based high-efficiency water reducer, and a naphthalenesulfonate water reducer.

[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 comprises the following steps:

[0028] Step a, accurately weighing each raw material of the concrete base;

[0029] Step b, putting the weighed raw materials of the concrete base material except the fiber reinforcement into a mixing device and stirring evenly;

[0030] Step c, adding a fiber reinforcement and water to the product of step b, and stirring evenly;

[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 present invention has the following beneficial effects:

[0033] The present invention first pre-treats the steel fiber to remove the oil and dirt on the surface thereof, then puts it into a silane hydrolyzate, uniformly disperses it, and reacts it with N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and the two are finally connected by chemical bonds to modify the surface characteristics of the steel fiber.

[0034] Furthermore, the present invention soaks the glass fiber in hydrogen peroxide to hydroxylate the surface of the glass fiber, then disperses it in acetone and adds 3-aminopropyltriethoxysilane, mixes evenly and then performs heat preservation reaction, and finally 3-aminopropyltriethoxysilane is grafted on the surface of the glass fiber to obtain pre-treated glass fiber. The obtained pre-treated glass fiber is evenly dispersed in N,N-dimethylformamide, and phthalic anhydride, tetrahydroxymethylmethane and diethylenetriamine are successively added thereto, and finally a considerable amount of macromolecular organic matter is grafted on the surface of the glass fiber, completing the hyperbranching of the glass fiber, and at the same time realizing the expansion of the three-dimensional spatial structure of the glass fiber, and finally obtaining a modified glass fiber.

[0035] The prepared modified steel fiber and modified glass fiber are put into an ethanol aqueous solution containing tetraethoxysilane, and then uniformly dispersed and stirred for reaction, and finally a layer of quite dense nano oxide is deposited on the surface of the modified steel fiber and the modified glass fiber, thereby effectively increasing the roughness of the surface, making the contact area between the modified steel fiber and the modified glass fiber larger, further enhancing the friction between the modified steel fiber and the concrete matrix, thereby significantly improving the tensile properties of the concrete, and effectively increasing the material toughness of the prepared concrete. In addition, the finer part of the gold tailings (particle size <100 mesh) in the present invention is used as the raw material of the alkali-activated cementitious material, and the coarser part (particle size >100 mesh) is used as the fine aggregate of the concrete, which realizes the resource utilization of solid waste materials, improves the comprehensive utilization rate of the tailings, and conforms to the development concept of green and low-carbon building materials. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] A gold tailings-based alkali-activated ultra-high performance concrete comprises a concrete base material, water and a fiber reinforcement; the concrete base material is composed of the following raw materials in parts by weight: 900 parts of alkali-activated cementitious materials, 200 parts of silica fume, 85 parts of machine-made sand, 25 parts of gold tailings sand, and 4 parts of polycarboxylic acid-based high-performance water reducing agents; the mass ratio of water to concrete base raw materials is 5.56:1.00, and the volumetric dosage range of the fiber reinforcement is 1.0%.

[0039] Among them, the fine aggregate is machine-made sand and gold tailings sand. Among them, the particle size of machine-made sand is 0.08mm, the fineness modulus is 2.6, the moisture content is 0.1%, and the mud content is 0.5%; the particle size of gold tailings sand is 0.2-0.4mm. The alkali activator is compounded by sodium hydroxide and water glass in a mass ratio of 1:1; the polycarboxylic acid high-performance water reducer is PC-1022 polyether polycarboxylic acid water reducer purchased from Suzhou Xingbang Chemical Building Materials Co., Ltd.

[0040] The preparation method of the fiber reinforcement is as follows: tetraethoxysilane is added into an ethanol aqueous solution with a concentration of 60wt% at a dosage ratio of 0.3g / mL, and after being evenly mixed, the pH is adjusted to 3.5 with dilute hydrochloric acid, and then 20% by mass of modified steel fiber and 10% by mass of modified glass fiber are added to the obtained mixed components, and after being evenly dispersed, the mixture is stirred and reacted at a temperature of 40°C for 8h; after the reaction is completed, the product components are filtered, and the obtained solid filter material is transferred to a drying device and dried at a temperature of 50°C for 3h; after drying, the obtained solid material is the fiber reinforcement.

[0041] The preparation method of the modified steel fiber comprises the following steps:

[0042] The first step is to immerse the steel fiber in a sodium hydroxide aqueous solution with a temperature of 40°C and a concentration of 20wt% for 40 minutes; after the immersion is completed, the steel fiber is fished out and washed twice with anhydrous ethanol and deionized water respectively, and then dried, and the obtained pretreated steel fiber is stored for standby use; wherein the steel fiber has a tensile strength of 2500MPa, a length of 12mm, and a diameter of 0.18mm;

[0043] The second step is to add 5% by volume of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane to the 80wt% ethanol aqueous solution, stir evenly, adjust the pH of the mixture to 4.5 with glacial acetic acid, and then stir and hydrolyze at 30°C for 5h, and store the obtained silane hydrolyzate for later use;

[0044] In the third step, the pretreated steel fiber is added to the silane hydrolyzate at a solid-liquid ratio of 0.05 g / mL, and reacted for 30 minutes after uniform dispersion; after the reaction is completed, the steel fiber is filtered out and transferred to a drying equipment, and dried at 90°C for 2 hours to obtain the modified steel fiber.

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

[0046] Step 1, adding glass fiber into 25wt% hydrogen peroxide at a solid-liquid ratio of 0.02g / mL, mixing and stirring evenly, heating to 105°C, and keeping the temperature at this temperature for 3h; after the reaction is completed, filtering out the glass fiber and drying it; wherein the length of the glass fiber is 10μm and the diameter is 8μm;

[0047] Step 2, the dried glass fiber is evenly dispersed in acetone at a solid-liquid ratio of 0.05 g / mL, 3-aminopropyltriethoxysilane is added in an amount 3 times the mass of the glass fiber, and the mixture is evenly mixed and reacted at a temperature of 80° C. for 5 hours; after the reaction is completed, the resultant components are filtered and dried in turn, and the obtained pre-treated glass fiber is stored for standby use;

[0048] Step three, uniformly dispersing the pretreated glass fiber in N,N-dimethylformamide at a solid-liquid ratio of 0.03 g / mL, and then adding 1 times the mass of phthalic anhydride and 1.2 times the mass of tetrahydroxymethylmethane of the pretreated glass fiber, mixing and stirring evenly, and heat-retaining the mixture at 110°C for 6 hours; after the reaction is completed, adding 3 times the mass of phthalic anhydride of diethylenetriamine to the product components, uniformly dispersing the mixture, and heat-retaining the mixture at 100°C for 5 hours; after the reaction is completed, filtering, washing and drying the reaction product in turn to obtain the modified glass fiber.

[0049] A method for preparing gold tailings-based alkali-activated ultra-high performance concrete comprises the following steps: accurately weighing various raw materials, modifying fibers using a fiber reinforcing agent, then putting various raw materials of the concrete base into a mixing device, stirring them evenly, and then adding the modified fibers and water; after mixing evenly, injecting the obtained mixed slurry into a mold for molding, and then steam curing for 48 hours or naturally curing for 28 days to obtain a finished product of the gold tailings-based alkali-activated ultra-high performance concrete.

[0050] Example 2

[0051] The preparation method of a 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 components of the concrete and the preparation method of the fiber reinforcement are not completely the same. The specific composition of the concrete product and the preparation method of the fiber reinforcement in this embodiment are as follows:

[0052] A gold tailings-based alkali-activated ultra-high performance concrete comprises a concrete base material, water and fiber; the concrete base material is composed of the following raw materials in parts by weight: the concrete base material is composed of the following raw materials in parts by weight: 950 parts of alkali-activated cementitious material, 220 parts of silica fume, 90 parts of machine-made sand, 20 parts of gold tailings sand, and 4 parts of polycarboxylic acid-based high-performance water reducing agent; the mass ratio of water to concrete base raw materials is 5.56:1.00, and the volume addition range of the fiber reinforcement is 1.0%.

[0053] Among them, the fine aggregates are machine-made sand and gold tailings sand. Among them, the particle size of the machine-made sand is 0.08mm, the fineness modulus is 2.6, the moisture content is 0.1%, and the mud content is 0.5%; the particle size of the gold tailings sand is 0.2-0.4mm. The alkali activator is compounded with sodium hydroxide and water glass in a mass ratio of 1:3.5; the polycarboxylic acid high-performance water reducer is PC-1022 polyether polycarboxylic acid water reducer purchased from Suzhou Xingbang Chemical Building Materials Co., Ltd.

[0054] The preparation method of the fiber reinforcement is as follows: tetraethoxysilane is added into an ethanol aqueous solution with a concentration of 70wt% at a dosage ratio of 0.35g / mL, and after being evenly mixed, the pH is adjusted to 4.0 with dilute hydrochloric acid, and then 25% of modified steel fiber and 15% of modified glass fiber are added to the obtained mixed components, and after being evenly dispersed, the mixture is stirred and reacted at a temperature of 45°C for 10 hours; after the reaction is completed, the product components are filtered, and the obtained solid filter material is transferred to a drying device and dried at a temperature of 60°C for 4 hours; after drying, the obtained solid material is the fiber reinforcement.

[0055] The preparation method of the modified steel fiber comprises the following steps:

[0056] In the first step, the steel fiber is immersed in a sodium hydroxide aqueous solution with a temperature of 50°C and a concentration of 20wt% for 50 minutes; after the immersion is completed, the steel fiber is fished out and washed with anhydrous ethanol and deionized water three times respectively, and then dried, and the obtained pretreated steel fiber is stored for standby use; wherein, the steel fiber has a tensile strength of 2500MPa, a length of 12mm, and a diameter of 0.18mm;

[0057] The second step is to add 6% by volume of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane to the 85wt% ethanol aqueous solution, stir evenly, adjust the pH of the mixture to 5.0 with glacial acetic acid, and then stir and hydrolyze at 35°C for 6h, and store the obtained silane hydrolyzate for later use;

[0058] In the third step, the pretreated steel fiber is put into the silane hydrolyzate at a solid-liquid ratio of 0.08 g / mL, and reacted for 40 minutes after uniform dispersion; after the reaction is completed, the steel fiber is filtered out and transferred to a drying equipment, and dried at 100°C for 3 hours to obtain the modified steel fiber.

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

[0060] Step 1, adding glass fiber into 30wt% hydrogen peroxide at a solid-liquid ratio of 0.05g / mL, mixing and stirring evenly, heating to 110°C, and keeping the temperature at this temperature for 4h; after the reaction is completed, filtering out the glass fiber and drying it; wherein the length of the glass fiber is 10μm and the diameter is 8μm;

[0061] Step 2, the dried glass fiber is uniformly dispersed in acetone at a solid-liquid ratio of 0.06 g / mL, 3-aminopropyltriethoxysilane is added in an amount 5 times the mass of the glass fiber, the mixture is uniformly mixed, and the mixture is reacted at a temperature of 80° C. for 6 hours; after the reaction is completed, the resultant components are filtered and dried in turn, and the obtained pre-treated glass fiber is stored for standby 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 1.5 times the mass of phthalic anhydride and 1.4 times the mass of tetrahydroxymethylmethane of the pretreated glass fiber, mix and stir evenly, and keep warm at 120°C for 8 hours; after the reaction is completed, add diethylenetriamine 5 times the mass of phthalic anhydride to the product components, disperse evenly, and keep warm at 110°C for 8 hours; after the reaction is completed, filter, wash and dry the reaction product in turn to obtain modified glass fiber.

[0063] Example 3

[0064] The preparation method of a 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 components of the concrete product and the preparation method of the fiber reinforcement are not completely the same. The specific composition of the concrete product and the preparation method of the fiber reinforcement in this embodiment are as follows:

[0065] A gold tailings-based alkali-activated ultra-high performance concrete comprises a concrete base material, water and a fiber reinforcement; the concrete base material is composed of the following raw materials in parts by weight: 1000 parts of alkali-activated cementitious material, 200 parts of silica fume, 90 parts of machine-made sand, 20 parts of gold tailings sand, and 4 parts of polycarboxylic acid-based high-performance water reducing agent; the mass ratio of water to concrete base raw materials is 5.88:1.00, and the volumetric dosage range of the fiber reinforcement is 1.0%.

[0066] Among them, the fine aggregates are machine-made sand and gold tailings sand. Among them, the particle size of the machine-made sand is 0.08mm, the fineness modulus is 2.6, the moisture content is 0.1%, and the mud content is 0.5%; the particle size of the gold tailings sand is 0.2-0.4mm. The alkali activator is compounded with sodium hydroxide and water glass in a mass ratio of 1:3.5; the polycarboxylic acid high-performance water reducer is PC-1022 polyether polycarboxylic acid water reducer purchased from Suzhou Xingbang Chemical Building Materials Co., Ltd.

[0067] The preparation method of the fiber reinforcing agent is as follows: tetraethoxysilane is added into an ethanol aqueous solution with a concentration of 75wt% at a dosage ratio of 0.4g / mL, and after being evenly mixed, the pH value is adjusted to 4.5 with dilute hydrochloric acid, and then 0.3 times the mass of modified steel fiber and 0.2 times the mass of modified glass fiber are added to the obtained mixed components, and after being evenly dispersed, the mixture is kept warm and stirred at a temperature of 50°C for 12 hours; after the reaction is completed, the product components are filtered, and the obtained solid filter material is transferred to a drying device and dried at a temperature of 70°C for 5 hours; after drying, the obtained solid material is the fiber reinforcing agent.

[0068] The preparation method of the modified steel fiber comprises the following steps:

[0069] In the first step, the steel fiber is immersed in a sodium hydroxide aqueous solution with a temperature of 60°C and a concentration of 25wt% for 60 minutes; after the immersion is completed, the steel fiber is fished out and washed with anhydrous ethanol and deionized water three times respectively, and then dried, and the obtained pretreated steel fiber is stored for standby use; wherein, the tensile strength of the steel fiber is 2500MPa, the length is 12mm, and the diameter is 0.18mm;

[0070] The second step is to add 8% by volume of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane to a 90wt% ethanol aqueous solution, stir evenly, adjust the pH of the mixture to 5.8 with glacial acetic acid, and then stir and hydrolyze at 40°C for 8h, and store the obtained silane hydrolyzate for later use;

[0071] In the third step, the pretreated steel fiber is added to the silane hydrolyzate at a solid-liquid ratio of 0.1 g / mL, and reacted for 50 minutes after uniform dispersion; after the reaction is completed, the steel fiber is filtered out and transferred to a drying equipment, and dried at 110°C for 4 hours to obtain the modified steel fiber.

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

[0073] Step 1, adding glass fiber into 30wt% hydrogen peroxide at a solid-liquid ratio of 0.05g / mL, mixing and stirring evenly, heating to 110°C, and keeping the temperature at this temperature for 5h; after the reaction is completed, filtering out the glass fiber and drying it; wherein the length of the glass fiber is 10μm and the diameter is 8μm;

[0074] Step 2, uniformly dispersing the dried glass fiber in acetone at a solid-liquid ratio of 0.1 g / mL, adding 3-aminopropyltriethoxysilane 6 times the mass of the glass fiber, mixing evenly and reacting at a temperature of 85° C. for 8 hours; after the reaction is completed, filtering and drying the resulting components in turn, and storing the obtained pre-treated glass fiber for standby use;

[0075] Step three, uniformly dispersing the pretreated glass fiber in N,N-dimethylformamide at a solid-liquid ratio of 0.08 g / mL, and then adding phthalic anhydride twice as much as the mass of the pretreated glass fiber and tetrahydroxymethylmethane 1.6 times as much as the mass of the pretreated glass fiber, stirring evenly, and keeping warm at 130°C for 10 hours; after the reaction is completed, adding diethylenetriamine 6 times as much as the mass of phthalic anhydride to the product components, uniformly dispersing, and keeping warm at 120°C for 10 hours; after the reaction is completed, filtering, washing and drying the reaction product in turn 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 a fiber mixture is used in this comparative example to replace the fiber reinforcement 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 the fiber reinforcement; that is, in this comparative example, an ethanol solution containing tetraethoxysilane is not used to treat the modified steel fiber and modified glass fiber.

[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 instead of modified steel fiber, and an equal amount of glass fiber is used instead of modified glass fiber; that is, the total amount of steel fiber and glass fiber in this comparative example is equal to the total amount of modified steel fiber and modified glass fiber 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 to 3 and Comparative Examples 1 to 2 were tested as follows, and the obtained test data were recorded in the following table:

[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 has ultra-high compressive and flexural strength, meets the requirements of the corresponding specifications, and has excellent durability and bending toughness, with outstanding performance. Furthermore, the present invention uses gold tailings as a raw material for preparing ultra-high performance concrete, realizes the resource utilization of solid waste materials, improves the comprehensive utilization rate of tailings, and complies with the concept of green and low-carbon development of building materials. This shows that the gold tailings-based alkali-activated ultra-high performance concrete and its preparation method provided by the present invention have broader market prospects and practical engineering value.

[0082] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present 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 material, a fiber reinforcement and water; characterized in that: The concrete base material is composed of the following raw materials in parts by weight: 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 and 4-6 parts of water reducer, wherein the particle size of the gold tailings is greater than 100 meshes; the mass ratio of water to alkali-activated cementitious material is 5.56:1.00; and the volumetric dosage range of the fiber reinforcement is 1.0-3.0%.

2. The gold tailings-based alkali-activated ultra-high performance concrete according to claim 1, characterized in that: The preparation method of the fiber reinforcement is: Step S1, adding tetraethoxysilane in a dosage ratio of 0.3-0.4 g / mL into an ethanol aqueous solution with a concentration of 60-75 wt%, and mixing evenly; Step S2, adjusting the pH of the solution obtained in step S1 to 3.5-4.5 with dilute hydrochloric acid; Step S3, adding 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 mixing them evenly; Step S4, stirring the reaction at a temperature of 40 to 50° C. for 8 to 12 hours; Step S5, after the reaction is completed, filtering the components obtained in step S4 to obtain a solid filter material; Step S6, transferring the obtained solid filter material into a drying device, and drying it at a temperature of 50 to 70° C. for 3 to 5 hours to obtain a fiber reinforcement.

3. The gold tailings-based alkali-activated ultra-high performance concrete according to claim 2, characterized in that: The preparation method of the modified steel fiber comprises the following steps: The first step is to soak the steel fiber in a sodium hydroxide aqueous solution with a temperature of 40 to 60° C. and a concentration of 20 to 25 wt % for 40 to 60 minutes; after the soaking is completed, the steel fiber is taken out and washed with anhydrous ethanol and deionized water for 2 to 3 times respectively, and then the steel fiber is dried, and the obtained pretreated steel fiber is stored for standby use; The second step is to add 5-8% by volume of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane to 80-90wt% ethanol aqueous solution, stir evenly, adjust the pH value of the mixture to 4.5-5.8 with glacial acetic acid, and then stir and hydrolyze at 30-40°C for 5-8h, and store the obtained silane hydrolyzate for later use; The third step is to put the pretreated steel fiber into the silane hydrolyzate at a solid-liquid ratio of 0.05 to 0.1 g / mL, and react for 30 to 50 minutes after uniform dispersion; The fourth step is to filter the product obtained in the third step, transfer the filtered solid product into a drying device, and dry it at 90-110° C. for 2-4 hours to obtain the modified steel fiber.

4. The gold tailings-based alkali-activated ultra-high performance concrete according to claim 2, characterized in that: The preparation method of the modified glass fiber comprises the following steps: Step 1: Add glass fiber into 25-30wt% hydrogen peroxide at a solid-liquid ratio of 0.02-0.05g / mL, mix and stir evenly, then heat to 105-110°C, and keep the temperature at this temperature for 3-5h; after the reaction is completed, filter out the glass fiber and dry it; Step 2, uniformly dispersing the dried glass fiber in acetone at a solid-liquid ratio of 0.05 to 0.1 g / mL, adding 3-aminopropyltriethoxysilane in an amount 3 to 6 times the mass of the glass fiber, mixing evenly and reacting at a temperature of 80 to 85° C. for 5 to 8 hours; after the reaction is completed, filtering and drying the resultant components in turn, and storing the obtained pre-treated glass fiber for standby use; Step 3, the pre-treated glass fiber is uniformly dispersed in N, N-dimethylformamide at a solid-liquid ratio of 0.03-0.08 g / mL, and then 1-2 times the mass of phthalic anhydride and 1.2-1.6 times the mass of tetramethylolmethane are added to the pre-treated glass fiber, and the mixture is stirred evenly and then reacted at a constant temperature of 110-130° C. for 6-10 hours; Step 4: add diethylenetriamine in an amount 3 to 6 times the mass of phthalic anhydride to the product obtained in step 3, disperse the mixture evenly, and react at a constant temperature of 100 to 120° C. for 5 to 10 hours; after the reaction is completed, filter, wash and dry the reaction product in turn to obtain modified glass fiber.

5. The gold tailings-based alkali-activated ultra-high performance concrete according to claim 1, characterized in that: The fine aggregate is any one of quartz sand, river sand and machine-made sand, with a particle size of 0.4-1.2 mm, a fineness modulus of 2.6-2.8, 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 0.2-0.4 mm.

6. The gold tailings-based alkali-activated ultra-high performance concrete according to claim 1, characterized in that: The alkaline activator is prepared by compounding sodium hydroxide and water glass in a mass ratio of 1:1 to 1:3.

5.

7. The gold tailings-based alkali-activated ultra-high performance concrete according to claim 1, characterized in that: The water reducer is selected from any one of a polycarboxylic acid-based high-performance water reducer, an aminosulfonate-based high-efficiency water reducer, and a naphthalenesulfonate water reducer.

8. The gold tailings-based alkali-activated ultra-high performance concrete according to claim 1, characterized in that: The air entraining agent is selected from any one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and rosin-based air entraining agents.

9. A method for preparing gold tailings-based alkali-activated ultra-high performance concrete according to any one of claims 1 to 8, characterized in that: The following steps are involved: 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 evenly; Step c, adding a fiber reinforcement and water to the product of step b, and stirring evenly; 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.

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