Coal gangue composite silicon-aluminum new material high-strength concrete and preparation method thereof

Abstract

The application discloses a kind of coal gangue composite silicon aluminum new material high-strength concrete and preparation method thereof, belong to concrete material technical field, including the following steps: water, cement, cement additive, fly ash, coal gangue composite silicon aluminum new material, natural sand, mechanism sand and full-grade recycled aggregate are mixed uniformly according to weight ratio, that is, the coal gangue composite silicon aluminum new material high-strength concrete prepared.The application is prepared into coal gangue composite silicon aluminum new material by decarburized coal gangue powder through high-fine grinding physical excitation and alkali-silica gel chemical excitation cooperation, and acrylamide-acrylic acid-sodium allyl sulfonate copolymer aqueous solution is used to surface coating modification to full-grade recycled aggregate, while compound naphthalene sulfonate formaldehyde condensate, methyl cellulose ether, aluminum chloride and magnesium chloride form multiple-effect cement additive, solve the technical problems of low coal gangue activity utilization rate, poor workability of recycled aggregate and insufficient later strength.

Description

Technical Field

[0001] This invention belongs to the field of concrete materials technology, specifically a new type of high-strength concrete made of coal gangue composite silicon-aluminum and its preparation method. Background Technology

[0002] Concrete is a composite material composed of cement, sand, water, admixtures, and other components. It is the most widely used structural material in basic construction projects such as civil engineering, water conservancy projects, road engineering, and underground engineering. With the rapid increase in the amount of construction waste generated and discharged, using construction waste to prepare recycled concrete aggregates and recycled concrete materials is an important way to practice environmental protection. Coal gangue-based concrete, which uses coal gangue as aggregate or admixture, shows promising application prospects in the field of building materials.

[0003] Patent application CN112521074A discloses a permeable concrete based on coal gangue and its preparation method. The permeable concrete comprises treated coal gangue, calcined coal gangue, water glass, a water-reducing agent, sodium hydroxide, and water; wherein the treated coal gangue particles are activated with a mixed aqueous solution of hydrofluoric acid and acetic acid to obtain the prepared treated coal gangue. The above concrete uses solid waste non-coal gangue as aggregate and cementitious material, thus giving the prepared concrete the advantage of high permeability. However, coal gangue-based concrete materials suffer from poor mechanical properties; coal gangue-based concrete with added ordinary water-reducing agents has poor fluidity and rapid slump loss, which cannot meet the needs of pumping construction and the technical and application requirements of today's high-performance concrete.

[0004] Patent application CN113772990A discloses a special admixture for high-strength concrete and its preparation method. The admixture comprises coal gangue fluidized bed slag, zeolite powder, an alkali-free accelerator, a water-reducing agent, mineral powder, and glass fiber. The alkali-free accelerator liquid, synthesized from aluminum sulfate, aluminum fluoride, water glass, and polyacrylamide, contains a certain amount of fluoride ions, sulfate ions, and aluminum ions, thereby accelerating cement hydration. However, this special admixture cannot improve the poor fluidity of coal gangue-based concrete materials; furthermore, accelerating cement hydration may further impair the flowability of the prepared cement.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problem of poor mechanical properties and fluidity of coal gangue-based concrete in the prior art.

[0007] The objective of this invention can be achieved through the following technical solutions: In a first aspect, this application provides a method for preparing high-strength concrete using a novel coal gangue composite silica-alumina material, comprising the following steps: Water, cement, cement admixtures, fly ash, coal gangue composite aluminosilicate new material, natural sand, manufactured sand, and fully graded recycled aggregate are mixed in a weight ratio of 30-40:50-60:0.12-0.15:5-10:15-30:65-90:32-45:195-270 to prepare high-strength concrete of coal gangue composite aluminosilicate new material.

[0008] Furthermore, the preparation method of cement admixtures includes the following steps: B1. React benzene with sulfuric acid at 125-135℃ for 20-30 min, then add concentrated sulfuric acid and heat to 145-160℃ for sulfonation reaction for 2-4 h; then add diamino polyethylene glycol, mix well, and continue to react at 120-130℃ for 1-2 h to form naphthalene sulfonate active substance. B2. Cool the active substance of naphthalene sulfonate to 120℃, hydrolyze it, then add formaldehyde dropwise, and keep it at 100-105℃ for 2.5-3.5 hours to form a product; adjust the pH of the product to neutral to form naphthalene sulfonate formaldehyde condensate. B3. Mix naphthalene sulfonate formaldehyde condensate, methyl cellulose ether, aluminum chloride and magnesium chloride evenly to form a cement admixture.

[0009] Further, in step B1, the concentration of concentrated sulfuric acid is 90-95 wt%; the ratio of benzene, sulfuric acid, concentrated sulfuric acid, diamino polyethylene glycol and formaldehyde is 3.9-7.8 g: 5-10 mL: 10-20 mL: 5-10 g: 3-10 g.

[0010] Further, in step B3, the weight ratio of naphthalene sulfonate formaldehyde condensate, methyl cellulose ether, aluminum chloride, and magnesium chloride is 60–70:0.09–0.1:0.05–0.1:0.05–0.1.

[0011] Furthermore, in step S2, the method for preparing fully graded recycled aggregate includes the following steps: A1. The coal gangue is initially crushed and screened to obtain coal gangue blocks with a particle size of 30-60mm; some of the coal gangue blocks are transferred to a sand making machine for grinding to form coal gangue powder with a particle size of 0.1-5mm; the coal gangue blocks and coal gangue powder are mixed evenly to form recycled mixed aggregate. A2. Mix 40-50% acrylamide aqueous solution and 40-50% acrylic acid aqueous solution, then add 20-30% ammonium persulfate solution to form a mixed system; heat the mixed system to 70-75℃ and react at this temperature for 2-4 hours, then add 40-50% sodium allyl sulfonate aqueous solution to form a polymer aqueous solution; A3. Mix the polymer aqueous solution and the recycled aggregate to form a fully graded recycled aggregate.

[0012] Further, in step A2, the weight ratio of acrylamide aqueous solution, acrylic acid aqueous solution, ammonium persulfate solution and sodium allyl sulfonate aqueous solution is 40-50:40-50:0.3-0.5:40-50; in step A2, the mass ratio of polymer aqueous solution and recycled mixed aggregate is 1:3-5.

[0013] Furthermore, the preparation method of the coal gangue composite aluminum-silicon material includes the following steps: C1. Decarbonized coal gangue powder is mixed with polyvinylpyrrolidone and desulfurized gypsum and then subjected to high-fine grinding to obtain a specific surface area of ​​600-800 m². 2 / kg of physically activated powder; C2. After mixing the physically activated powder with slag powder, silicate cement clinker, and added activator, continue grinding to obtain a specific surface area of ​​800-1000 m². 2 / kg of coal gangue composite silicon-aluminum new material; wherein, by weight percentage, the coal gangue composite silicon-aluminum new material contains 50% to 55% decarburized coal gangue powder, 38% to 38.5% slag powder, 5% to 10% silicate cement clinker and 1.5% to 2% added activator.

[0014] Further, in step C1, the amount of polyvinylpyrrolidone used is 0.03% to 0.05% of the mass of decarbonized coal gangue powder, and the amount of desulfurized gypsum used is 0.8% to 1.5% of the mass of decarbonized coal gangue powder; in step C2, the added activator includes, by weight percentage, 35% to 45% alkali powder, 45% to 55% alkali silica gel precursor, 5% to 10% triethanolamine, and the balance aluminum sulfate.

[0015] Secondly, this application provides a new type of high-strength concrete made from coal gangue composite silicon-aluminum, which is prepared using a method for preparing this new type of high-strength concrete made from coal gangue composite silicon-aluminum.

[0016] The present invention has the following beneficial effects: 1. Benzenesulfonic acid first reacts with diamino polyethylene glycol to synthesize a surfactant-like active substance, naphthalenesulfonate. Then, formaldehyde is added and polymerized to obtain a high-molecular-weight polymer, naphthalenesulfonate formaldehyde condensate. The naphthalenesulfonate formaldehyde condensate, methyl cellulose ether, magnesium chloride, and aluminum chloride are mixed to prepare the cement admixture. The addition of the naphthalenesulfonate formaldehyde condensate not only significantly improves the strength of the prepared concrete but also acts as a high-molecular-weight surfactant, improving the fluidity and uniformity of the cement paste. When using construction waste coal gangue as recycled coarse and fine aggregates, the high water absorption rate of the recycled aggregates results in poor workability and rapid slump loss in the prepared concrete. Adding cement admixtures can avoid these drawbacks.

[0017] 2. Methylcellulose ether has air-entraining and retarding effects; the added aluminum ions can react with cement to form new aluminum phase minerals; in addition, aluminum ions can replace silicon ions in hydrated calcium silicate to form aluminum-rich CASH gel. This gel has higher strength and durability and can promote cement hydration, while magnesium ions can inhibit the dissolution of aluminum phase minerals. The cement admixture prepared by this invention can not only accelerate the early strength development of concrete, but also, according to experimental data, the coal gangue composite silica-alumina new material high-strength concrete with the above admixture added also has high strength over a long period of 28 days.

[0018] 3. Coal gangue is mainly composed of silicon and aluminum, and also contains a certain amount of alkaline oxides such as potassium oxide and sodium oxide. These alkaline oxides can increase the alkalinity of the cement during hydration. In addition, the addition of fly ash and ultrafine powder can reduce the density of the gel material and effectively control water bleeding. However, as recycled coarse and fine aggregates, coal gangue, along with the added manufactured sand, has a porous structure with strong adsorption properties, making the synthesized cement concrete more susceptible to erosion. Therefore, this invention uses a polymer aqueous solution as a water film to coat the fully graded recycled aggregates. Both the polymer aqueous solution and fly ash can fill the micropores of the synthesized coal gangue composite silicon-aluminum new material high-strength concrete, further enhancing the overall strength. 4. By mixing decarbonized coal gangue powder with polyvinylpyrrolidone and desulfurized gypsum and then physically activating it through high-fine grinding, and then mixing it with slag powder, silicate cement clinker, alkali powder, alkali-silica gel precursor, triethanolamine and aluminum sulfate for further grinding and chemical activation, a new coal gangue composite aluminosilicate material is synergistically prepared and introduced as a mineral admixture into the concrete cementitious system. This solves the technical problems of low activity utilization rate of decarbonized coal gangue powder, slow strength growth of concrete in the later stage, and high porosity in the interface transition zone in the existing technology. It achieves a significant improvement in the later stage strength of concrete and densification of the microstructure, while increasing the added value of coal gangue solid waste. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1

[0020] This embodiment provides a method for preparing a cement admixture for high-strength concrete made from a new coal gangue composite silica-alumina material, comprising the following steps: B1, 3.9 g of benzene, and 5 mL of sulfuric acid were added to a round-bottom flask and mixed thoroughly. The mixture was then heated in an oil bath to 125 °C and reacted at this temperature for 20 min. Next, 10 mL of 90 wt% concentrated sulfuric acid was added to the round-bottom flask. The temperature of the round-bottom flask was raised to 145 °C, and the sulfonation reaction was carried out at this temperature for 2 h. Finally, 50 g of diamino polyethylene glycol was added to the round-bottom flask, mixed thoroughly, and the reaction was continued at 120 °C for 1 h to obtain the prepared naphthalene sulfonate active material.

[0021] B2. Remove the oil bath from the round-bottom flask and cool it to 120℃. Then, add 3 mL of cold water to the round-bottom flask for hydrolysis. Next, add 3 g of formaldehyde dropwise to the round-bottom flask while maintaining the temperature at 100℃ for 2.5 h to form the product. Add 3 wt% NaOH solution to the product to adjust its pH to neutral, which is the prepared naphthalenesulfonate formaldehyde condensate.

[0022] B3. According to the weight, 60 parts of naphthalene sulfonate formaldehyde condensate, 0.09 parts of methyl cellulose ether, 0.05 parts of aluminum chloride and 0.05 parts of magnesium chloride are mixed evenly to obtain the synthesized cement admixture. Example 2

[0023] This embodiment provides a method for preparing a cement admixture for high-strength concrete made from a new coal gangue composite silica-alumina material, comprising the following steps: B1, 6.5 g of benzene and 8 mL of sulfuric acid were added to a round-bottom flask and mixed thoroughly. The mixture was then heated in an oil bath to 130 °C and reacted at this temperature for 25 min. Next, 15 mL of 92 wt% concentrated sulfuric acid was added to the round-bottom flask. The temperature of the round-bottom flask was raised to 155 °C, and the sulfonation reaction was carried out at this temperature for 3 h. Finally, 8 g of diamino polyethylene glycol was added to the round-bottom flask, mixed thoroughly, and the reaction was continued at 125 °C for 1.5 h to obtain the prepared naphthalene sulfonate active material.

[0024] B2. Remove the oil bath from the round-bottom flask and cool it to 120℃. Then, add 5mL of cold water to the round-bottom flask for hydrolysis. Next, add 7g of formaldehyde dropwise to the round-bottom flask while maintaining the temperature at 102℃ for 3 hours to form the product. Add 6wt% NaOH solution to the product to adjust its pH to neutral, which is the prepared naphthalenesulfonate formaldehyde condensate.

[0025] B3. According to the weight parts, 65 parts of naphthalene sulfonate formaldehyde condensate, 0.01 parts of methyl cellulose ether, 0.08 parts of aluminum chloride and 0.07 parts of magnesium chloride are mixed evenly to obtain the synthesized cement admixture. Example 3

[0026] This embodiment provides a method for preparing a cement admixture for high-strength concrete made from a new coal gangue composite silica-alumina material, comprising the following steps: B1, 7.8 g of benzene, and 10 mL of sulfuric acid were added to a round-bottom flask and mixed thoroughly. The mixture was then heated in an oil bath to 135 °C and reacted at this temperature for 30 min. Next, 20 mL of 95 wt% concentrated sulfuric acid was added to the round-bottom flask. The temperature of the round-bottom flask was raised to 160 °C, and the sulfonation reaction was carried out at this temperature for 4 h. Finally, 10 g of diamino polyethylene glycol was added to the round-bottom flask, mixed thoroughly, and the reaction was continued at 130 °C for 2 h to obtain the prepared naphthalene sulfonate active material.

[0027] B2. Remove the oil bath from the round-bottom flask and cool it to 120℃. Then, add 7mL of cold water to the round-bottom flask for hydrolysis. Next, add 10g of formaldehyde dropwise to the round-bottom flask while maintaining the temperature at 1105℃. Keep the flask at this temperature for 3.5h to form the product. Add 8wt% NaOH solution to the product to adjust its pH to neutral, which is the prepared naphthalenesulfonate formaldehyde condensate.

[0028] B3. According to the weight, 70 parts of naphthalene sulfonate formaldehyde condensate, 0.1 parts of methyl cellulose ether, 0.1 parts of aluminum chloride and 0.1 parts of magnesium chloride are mixed evenly to obtain the synthesized cement admixture. Example 4

[0029] This embodiment provides a method for preparing fully graded recycled aggregate for high-strength concrete made from a new coal gangue composite silica-alumina material, comprising the following steps: A1. Coal gangue is initially crushed and screened in a jaw crusher to obtain coal gangue blocks with an average particle size of 60mm. Half of the coal gangue blocks by weight are transferred to a sand making machine for further grinding to form coal gangue powder with an average particle size of 0.1mm. The coal gangue blocks are used as coarse aggregate, and the coal gangue powder is used as fine aggregate. The two are mixed to form recycled mixed aggregate.

[0030] A2. Acrylamide was prepared into a 40% (w / w) aqueous solution; acrylic acid was prepared into a 40% (w / w) aqueous solution; sodium allyl sulfonate was prepared into a 20% (w / w) aqueous solution; and ammonium persulfate was prepared into a 5% (w / w) initiator solution. First, 40 parts by weight of the acrylamide aqueous solution and 40 parts by weight of the acrylic acid aqueous solution were added to the reactor. Then, 0.3 parts by weight of the initiator solution were added dropwise to the reactor to form a mixed system. The mixed system was heated to 70°C and reacted at this temperature for 2 hours. Then, 40 parts by weight of the sodium allyl sulfonate aqueous solution were added dropwise to the mixed system, completing the addition within 1 hour to form a polymer aqueous solution.

[0031] A3. The polymer aqueous solution and the recycled aggregate are mixed at a mass ratio of 1:3 to obtain the fully graded recycled aggregate. Example 5

[0032] This embodiment provides a method for preparing fully graded recycled aggregate for high-strength concrete made from a new coal gangue composite silica-alumina material, comprising the following steps: A1. Coal gangue is initially crushed and screened in a jaw crusher to obtain coal gangue blocks with a particle size of 40mm. One-third of the coal gangue blocks by weight are transferred to a sand making machine for further grinding to form coal gangue powder with a particle size of 5mm. The coal gangue blocks are used as coarse aggregate, and the coal gangue powder is used as fine aggregate. The two are mixed to form recycled mixed aggregate.

[0033] A2. Acrylamide was prepared into a 45% (w / w) aqueous solution; acrylic acid was prepared into a 45% (w / w) aqueous solution; sodium allyl sulfonate was prepared into a 26% (w / w) aqueous solution; and ammonium persulfate was prepared into a 10% (w / w) initiator solution. First, 45 parts by weight of the acrylamide aqueous solution and 45 parts by weight of the acrylic acid aqueous solution were added to the reactor. Then, 0.4 parts by weight of the initiator solution were added dropwise to the reactor to form a mixed system. The mixed system was heated to 71°C and reacted at this temperature for 3.3 hours. Then, 46 parts by weight of the sodium allyl sulfonate aqueous solution were added dropwise to the mixed system, completing the addition within 1.5 hours to form a polymer aqueous solution.

[0034] A3. The polymer aqueous solution and the recycled aggregate are mixed at a mass ratio of 1:4 to obtain the fully graded recycled aggregate. Example 6

[0035] This embodiment provides a method for preparing fully graded recycled aggregate for high-strength concrete made from a new coal gangue composite silica-alumina material, comprising the following steps: A1. Coal gangue is initially crushed in a jaw crusher and screened to obtain coal gangue blocks with a particle size of 30-60mm. One-third of the coal gangue blocks by weight are transferred to a sand making machine for further grinding to form 5mm coal gangue powder. The coal gangue blocks are used as coarse aggregate, and the coal gangue powder is used as fine aggregate. The two are mixed to form recycled mixed aggregate.

[0036] A2. Acrylamide was prepared into a 50% (w / w) aqueous solution; acrylic acid was prepared into a 50% (w / w) aqueous solution; sodium allyl sulfonate was prepared into a 30% (w / w) aqueous solution; and ammonium persulfate was prepared into a 15% (w / w) initiator solution. First, 50 parts by weight of the acrylamide aqueous solution and 50 parts by weight of the acrylic acid aqueous solution were added to the reactor. Then, 0.5 parts by weight of the initiator solution were added dropwise to the reactor to form a mixed system. The mixed system was heated to 75°C and reacted at this temperature for 4 hours. Then, 50 parts by weight of the sodium allyl sulfonate aqueous solution were added dropwise to the mixed system, completing the addition within 2 hours to form a polymer aqueous solution.

[0037] A3. The polymer aqueous solution and the recycled aggregate are mixed at a mass ratio of 1:5 to obtain the fully graded recycled aggregate. Example 7

[0038] This embodiment provides a method for preparing a new coal gangue composite aluminosilicate material for high-strength concrete, comprising the following steps: C1. The decarbonized coal gangue powder is crushed to a particle size of less than 3 cm using a jaw crusher, and then coarsely ground using a grinding mill to obtain a specific surface area of ​​500 m². 2 / kg of decarbonized coal gangue powder; the above decarbonized coal gangue powder is mixed with polyvinylpyrrolidone and grade I desulfurized gypsum and then subjected to high-fine grinding to obtain a specific surface area of ​​600m². 2 / kg of physically activated powder; wherein, the amount of polyvinylpyrrolidone is 0.05% of the mass of decarbonized coal gangue powder, and the amount of desulfurized gypsum is 1.5% of the mass of decarbonized coal gangue powder.

[0039] C2. The physically activated powder is mixed with slag powder, silicate cement clinker, and added activator, and then further ground to obtain a specific surface area of ​​800 m². 2 / kg of coal gangue composite silicon-aluminum new material; wherein, by weight percentage, the coal gangue composite silicon-aluminum new material contains 50% decarburized coal gangue powder, 38% slag powder, 10% silicate cement clinker and 2% added activator; the added activator by weight percentage includes 35% sodium hydroxide, 45% lithium methylsilicate, 10% triethanolamine and 10% aluminum sulfate. Example 8

[0040] This embodiment provides a method for preparing a new coal gangue composite aluminosilicate material for high-strength concrete, comprising the following steps: C1. The decarbonized coal gangue powder is crushed to a particle size of less than 3 cm using a jaw crusher, and then coarsely ground using a grinding mill to obtain a specific surface area of ​​550 m². 2 / kg of decarbonized coal gangue powder; the above decarbonized coal gangue powder is mixed with polyvinylpyrrolidone and grade I desulfurized gypsum and then subjected to high-fine grinding to obtain a specific surface area of ​​700m². 2 / kg of physically activated powder; wherein, the amount of polyvinylpyrrolidone is 0.04% of the mass of decarbonized coal gangue powder, and the amount of desulfurized gypsum is 1.1% of the mass of decarbonized coal gangue powder.

[0041] C2. The physically activated powder is mixed with slag powder, silicate cement clinker, and added activator, and then further ground to obtain a specific surface area of ​​900 m². 2 / kg of coal gangue composite silicon-aluminum new material; wherein, by weight percentage, the coal gangue composite silicon-aluminum new material contains 52% decarburized coal gangue powder, 38.2% slag powder, 8% silicate cement clinker and 1.8% added activator; the added activator by weight percentage includes 40% sodium hydroxide, 48% lithium methylsilicate, 7% triethanolamine and 5% aluminum sulfate. Example 9

[0042] This embodiment provides a method for preparing a new coal gangue composite aluminosilicate material for high-strength concrete, comprising the following steps: C1. The decarbonized coal gangue powder is crushed to a particle size of less than 3 cm using a jaw crusher, and then coarsely ground using a grinding mill to obtain a specific surface area of ​​600 m². 2 / kg of decarbonized coal gangue powder; the above decarbonized coal gangue powder is mixed with polyvinylpyrrolidone and grade I desulfurized gypsum and then subjected to high-fine grinding to obtain a specific surface area of ​​800m². 2 / kg of physically activated powder; wherein, the amount of polyvinylpyrrolidone is 0.03% of the mass of decarbonized coal gangue powder, and the amount of desulfurized gypsum is 0.8% of the mass of decarbonized coal gangue powder.

[0043] C2. After mixing the physically activated powder with slag powder, silicate cement clinker, and added activator, further grinding was carried out to obtain a specific surface area of ​​1000 m². 2 / kg of coal gangue composite silicon-aluminum new material; wherein, by weight percentage, the coal gangue composite silicon-aluminum new material contains 55% decarburized coal gangue powder, 38.5% slag powder, 5% silicate cement clinker and 1.5% added activator; the added activator by weight percentage includes 45% sodium hydroxide, 45% potassium methylsilicate, 5% triethanolamine and 5% aluminum sulfate. Example 10

[0044] This embodiment provides a method for preparing high-strength concrete using a novel coal gangue composite silica-alumina material, comprising the following steps: The high-strength concrete made from coal gangue composite silicon-aluminum material is prepared by mixing 30 parts water, 50 parts cement, 0.12 parts cement admixture prepared in Example 2, 5 parts fly ash, 15 parts coal gangue composite silicon-aluminum material prepared in Example 7, 65 parts natural sand, 32 parts manufactured sand, and 195 parts fully graded recycled aggregate prepared in Example 4 according to the weight ratio. Example 11

[0045] This embodiment provides a method for preparing high-strength concrete using a novel coal gangue composite silica-alumina material, comprising the following steps: The high-strength concrete made from coal gangue composite silica-alumina material is prepared by mixing 35 parts water, 55 parts cement, 0.13 parts cement admixture prepared in Example 2, 8 parts fly ash, 22 parts coal gangue composite silica-alumina material prepared in Example 8, 78 parts natural sand, 38 parts manufactured sand, and 225 parts fully graded recycled aggregate prepared in Example 5 according to the weight ratio. Example 12

[0046] This embodiment provides a method for preparing high-strength concrete using a novel coal gangue composite silica-alumina material, comprising the following steps: The high-strength concrete made from coal gangue composite silica-alumina material is prepared by mixing 40 parts water, 60 parts cement, 0.15 parts cement admixture prepared in Example 3, 10 parts fly ash, 30 parts coal gangue composite silica-alumina material prepared in Example 9, 90 parts natural sand, 45 parts manufactured sand, and 270 parts fully graded recycled aggregate prepared in Example 6 according to the weight ratio.

[0047] Comparative Example 1 This comparative example provides a method for preparing high-strength concrete using a new coal gangue composite silicon-aluminum material. Compared to Example 3, in step B1 of preparing the cement admixture, dioxy polyethylene glycol was not added.

[0048] Comparative Example 2 This comparative example provides a method for preparing high-strength concrete using a novel coal gangue composite silica-alumina material. Compared to Example 6, the method for preparing the polymer aqueous solution differs when preparing the fully graded recycled aggregate, and includes the following steps: Acrylamide was prepared into a 50% (w / w) aqueous solution; acrylic acid was prepared into a 50% (w / w) aqueous solution; sodium allyl sulfonate was prepared into a 30% (w / w) aqueous solution; and ammonium persulfate was prepared into a 15% (w / w) initiator solution. By weight, 50 parts of the acrylamide aqueous solution and 50 parts of the acrylic acid aqueous solution were first added to a reaction vessel, followed by the dropwise addition of 0.5 parts of the initiator solution to form a mixed system. The mixed system was heated to 75°C and reacted at this temperature for 4 hours to obtain the prepared polymer aqueous solution.

[0049] Comparative Example 3 This comparative example provides a method for preparing high-strength concrete using a new coal gangue composite silicon-aluminum material. Compared to Example 12, 10 parts of fly ash, 90 parts of natural sand, and 45 parts of manufactured sand are replaced with 145 parts of manufactured sand.

[0050] Performance testing: According to the "Standard for Test Methods of Mechanical Properties of Ordinary Concrete", the high-strength coal gangue composite silica-alumina new material concrete prepared in Examples 10-12 and Comparative Examples 1-3 were prepared into standard cubic specimens of 150mm×150mm×150mm and cured. The curing conditions were 20℃ and 95%RH, and the curing time was 7 days and 28 days respectively. They were still labeled as Examples 10-12 and Comparative Examples 1-3.

[0051] 1. The compressive strength of specimens cured for 7 days and 28 days was tested using a fully automatic compression testing machine. The loading rate of the machine was 0.5 MPa / s. Three specimens were prepared for each test group, and their average strength value was recorded as the final test result to minimize measurement error.

[0052] 2. According to GB / T50080-2002 "Standard for Test Methods of Performance of Ordinary Concrete Mixtures", the apparent density of the coal gangue composite silicon-aluminum new material high-strength concrete prepared in Examples 10-12 and Comparative Examples 1-3 was tested in sequence.

[0053] 3. The high-strength concrete made from coal gangue composite silicon-aluminum alloy prepared in Examples 10-12 of this invention was prepared into samples measuring 175mm × 185mm × 150mm and transferred to Huaibei Construction Engineering Quality Testing Center Co., Ltd. for impermeability testing. The samples were tested for permeability under 0.7MPa water pressure using a fully automatic concrete permeability analyzer.

[0054] 4. The slump test was used to test the flowability of the coal gangue composite silicon-aluminum new material high-strength concrete prepared in Examples 10-12 and Comparative Examples 1-3. The specific test results are shown in Table 1.

[0055] Table 1. Sample Performance Test Data

[0056] Data Analysis: The high-strength concrete made from coal gangue composite aluminosilicate new material prepared in Examples 10-12 of this invention exhibits high compressive strength and high apparent density. In preparing this high-strength concrete, the addition of the coal gangue composite aluminosilicate new material, microporous manufactured sand, and fly ash with a large specific surface area effectively adsorbs cement and fills the gaps with fully graded recycled aggregates. The coal gangue composite aluminosilicate new material is prepared through physical activation by grinding aids of polyvinylpyrrolidone and desulfurized gypsum, and synergistic chemical activation by alkali powder, alkali silica gel precursor, triethanolamine, and aluminum sulfate, achieving a specific surface area of ​​800-1000 m². 2 / kg, rich in amorphous SiO2 and active Al2O3, exhibits significant pozzolanic and micro-filling effects. It can undergo secondary reactions with cement hydration products Ca(OH)2 to generate additional hydrated calcium silicate gel and hydrated calcium aluminate gel, densifying the interfacial transition zone and thus improving the later-stage strength and impermeability durability of concrete. Therefore, the high-strength concrete made from coal gangue composite silica-alumina composite material prepared in this invention has high strength and high apparent density.

[0057] In Comparative Example 3, compared to Example 12, 10 parts of fly ash, 90 parts of natural sand, and 45 parts of manufactured sand were replaced with 145 parts of manufactured sand. Due to the absence of the pozzolanic effect and micro-filling effect of the coal gangue composite aluminosilicate new material, it was unable to undergo a secondary reaction with cement hydration products to generate additional hydration gel. The porosity of the interface transition zone increased, and the subsequent strength growth was limited. At the same time, the filling and adsorption effect of fly ash and the gradation optimization effect of natural sand were missing, resulting in a poorer filling and adsorption effect. Therefore, the strength and apparent density values ​​of the high-strength concrete made of coal gangue composite aluminosilicate new material prepared in Comparative Example 3 were reduced.

[0058] According to the data in Table 1, the high-strength concrete made from coal gangue composite silica-alumina materials prepared in Examples 10-12 of this invention meets the waterproofing requirements for concrete, with an impermeability grade of P6. Furthermore, the prepared high-strength concrete exhibits good fluidity and a high slump value. However, in Comparative Example 1, dioxyethylene glycol was not added in step B1 during the preparation of the cement admixture; therefore, the synthesized cement admixture's performance in improving the fluidity and uniformity of the cement paste deteriorated, resulting in a lower slump value.

[0059] In Comparative Example 2, sodium allyl sulfonate aqueous solution was not added during the preparation of the polymer aqueous solution. The polymer aqueous solutions prepared in Examples 4-6 contain sulfonate groups, which can undergo electrostatic adsorption with the cement admixture. Therefore, this can further enhance the cement admixture's ability to break down the cement flocculation structure, release free water, enhance lubrication, and improve the fluidity of the prepared coal gangue composite aluminosilicate high-strength concrete. Therefore, the coal gangue composite aluminosilicate high-strength concrete prepared in Comparative Example 2 suffers from a decrease in slump value.

[0060] In addition, this application also provides a new type of high-strength concrete made from coal gangue composite silicon-aluminum, which is prepared by a method for preparing this new type of high-strength concrete made from coal gangue composite silicon-aluminum.

[0061] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0062] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0063] 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 specific implementations. 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 method for preparing a new type of high-strength concrete using coal gangue composite silica-alumina materials, characterized in that, Includes the following steps: Water, cement, cement admixtures, fly ash, coal gangue composite aluminosilicate new material, natural sand, manufactured sand, and fully graded recycled aggregate are mixed in a weight ratio of 30-40:50-60:0.12-0.15:5-10:15-30:65-90:32-45:195-270 to prepare high-strength concrete of coal gangue composite aluminosilicate new material.

2. The method for preparing a new type of high-strength concrete using coal gangue composite silicon-aluminum as described in claim 1, characterized in that, The method for preparing the cement admixture includes the following steps: B1. React benzene with sulfuric acid at 125-135℃ for 20-30 min, then add concentrated sulfuric acid and heat to 145-160℃ for sulfonation reaction for 2-4 h; then add diamino polyethylene glycol, mix well, and continue to react at 120-130℃ for 1-2 h to form naphthalene sulfonate active substance. B2. Cool the active substance of naphthalene sulfonate to 120℃, hydrolyze it, then add formaldehyde dropwise, and keep it at 100-105℃ for 2.5-3.5 hours to form a product; adjust the pH of the product to neutral to form naphthalene sulfonate formaldehyde condensate. B3. Mix naphthalene sulfonate formaldehyde condensate, methyl cellulose ether, aluminum chloride and magnesium chloride evenly to form a cement admixture.

3. The method for preparing a new type of high-strength concrete using coal gangue composite silica-alumina as described in claim 2, characterized in that, In step B1, the concentration of concentrated sulfuric acid is 90-95 wt%; the ratio of benzene, sulfuric acid, concentrated sulfuric acid, diamino polyethylene glycol and formaldehyde is 3.9-7.8 g: 5-10 mL: 10-20 mL: 5-10 g: 3-10 g.

4. The method for preparing a new type of high-strength concrete using coal gangue composite silicon-aluminum material according to claim 2, characterized in that, In step B3, the weight ratio of naphthalenesulfonate formaldehyde condensate, methylcellulose ether, aluminum chloride, and magnesium chloride is 60–70: 0.09～0.1:0.05～0.1:0.05～0.1。 5. The method for preparing a new type of high-strength concrete using coal gangue composite silicon-aluminum as described in claim 1, characterized in that, In step S2, the method for preparing the fully graded recycled aggregate includes the following steps: A1. The coal gangue is initially crushed and screened to obtain coal gangue blocks with a particle size of 30-60mm; some of the coal gangue blocks are transferred to a sand making machine for grinding to form coal gangue powder with a particle size of 0.1-5mm; the coal gangue blocks and coal gangue powder are mixed evenly to form recycled mixed aggregate. A2. Mix 40-50% acrylamide aqueous solution and 40-50% acrylic acid aqueous solution, then add 20-30% ammonium persulfate solution to form a mixed system; heat the mixed system to 70-75℃ and react at this temperature for 2-4 hours, then add 40-50% sodium allyl sulfonate aqueous solution to form a polymer aqueous solution; A3. Mix the polymer aqueous solution and the recycled aggregate to form a fully graded recycled aggregate.

6. The method for preparing a new type of high-strength concrete using coal gangue composite silicon-aluminum material according to claim 5, characterized in that, In step A2, the weight ratio of acrylamide aqueous solution, acrylic acid aqueous solution, ammonium persulfate solution and sodium allyl sulfonate aqueous solution is 40-50:40-50:0.3-0.5:40-50; in step A2, the mass ratio of polymer aqueous solution and recycled mixed aggregate is 1:3-5.

7. The method for preparing a new type of high-strength concrete using coal gangue composite silicon-aluminum as described in claim 1, characterized in that, The preparation method of the coal gangue composite silicon-aluminum novel material includes the following steps: C1. Decarbonized coal gangue powder is mixed with polyvinylpyrrolidone and desulfurized gypsum and then subjected to high-fine grinding to obtain a specific surface area of ​​600-800 m². 2 / kg of physically activated powder; C2. After mixing the physically activated powder with slag powder, silicate cement clinker, and added activator, continue grinding to obtain a specific surface area of ​​800-1000 m². 2 / kg of coal gangue composite silicon-aluminum new material; wherein, by weight percentage, the coal gangue composite silicon-aluminum new material contains 50% to 55% decarburized coal gangue powder, 38% to 38.5% slag powder, 5% to 10% silicate cement clinker and 1.5% to 2% added activator.

8. The method for preparing a new type of high-strength concrete using coal gangue composite silicon-aluminum as described in claim 7, characterized in that, In step C1, the amount of polyvinylpyrrolidone used is 0.03% to 0.05% of the mass of decarbonized coal gangue powder, and the amount of desulfurized gypsum used is 0.8% to 1.5% of the mass of decarbonized coal gangue powder; in step C2, the added activator includes, by weight percentage, 35% to 45% alkali powder, 45% to 55% alkali silica gel precursor, 5% to 10% triethanolamine, and the balance aluminum sulfate.

9. A novel high-strength concrete made from coal gangue composite silica-alumina materials, characterized in that, It was prepared using the preparation method of a new coal gangue composite silicon-aluminum high-strength concrete as described in any one of claims 1 to 8.

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