A kind of full solid waste modified coal gangue high-strength concrete and a preparation method thereof
By crushing and surface-activating the coal gangue aggregate, and using interface modifiers and reinforcing agents, the problem of weak bonding between the coal gangue aggregate and cementitious materials was solved, thereby improving the mechanical properties and durability of concrete.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TAIYUAN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2026-03-13
- Publication Date
- 2026-06-05
AI Technical Summary
Existing coal gangue aggregates have smooth surfaces and low porosity, resulting in weak interfacial bonding with cementitious materials and poor mechanical properties of concrete.
By crushing, screening, and surface-activating modification of coal gangue aggregates, combined with the use of interface modifiers and reinforcing agents, the interfacial bonding force between aggregates and slurry is improved and the hydration process of cementitious materials is optimized.
It significantly improved the aggregate-slurry interface bonding force, and enhanced the mechanical properties and durability of high-strength concrete made from all-solid waste modified coal gangue.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of solid waste resource utilization technology, specifically to a high-strength concrete made from modified coal gangue made entirely from solid waste and its preparation method. Background Technology
[0002] With the acceleration of my country's industrialization process, the amount of industrial solid waste generated has been increasing year by year. Among them, coal gangue, slag, fly ash and red mud are several types of industrial solid waste with large generation volumes. Coal gangue is solid waste generated during coal mining and washing. Red mud is a highly alkaline waste residue generated during alumina production. Large-scale stockpiling not only occupies land but also causes serious pollution to the surrounding environment.
[0003] As the most widely used building material, concrete requires a large amount of natural resources for the preparation of its aggregates and cementitious materials. Using industrial solid waste in concrete preparation can not only solve the problem of solid waste storage, but also replace natural resources, which has important environmental and economic significance. At present, there are research reports on using coal gangue as aggregate to prepare concrete. However, due to the smooth surface and low porosity of coal gangue aggregate, the interfacial bonding force with cementitious materials is weak, resulting in poor mechanical properties of concrete.
[0004] Therefore, developing a high-strength concrete made from modified coal gangue and its preparation method is of great significance in the field of solid waste resource utilization technology. Summary of the Invention
[0005] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a high-strength concrete made from all-solid waste modified coal gangue and its preparation method: it solves the problem that the existing coal gangue aggregate has a smooth surface, low porosity, and weak interfacial bonding with cementitious materials, resulting in poor mechanical properties of concrete.
[0006] The objective of this invention can be achieved through the following technical solutions: In a first aspect, this application provides a high-strength concrete made entirely from solid waste modified coal gangue, comprising the following components by weight: 120-180 parts modified coal gangue aggregate, 50-100 parts cementitious material, 4-8 parts alkali activator, 2-5 parts interface modifier, 5-12 parts reinforcing agent, and 20-25 parts deionized water; The modified coal gangue aggregate is obtained by crushing, screening, and surface activation modification of coal gangue; the coal gangue is sourced from Yumei Bulk Coal Technology Co., Ltd.; the cementitious material is a mixture of 50-60 parts slag, 20-30 parts fly ash, and 15-25 parts red mud, with a specific surface area ≥450 m². 2 / kg; the slag is in powder form, sourced from Fengfeng Mineral Products Processing Plant in Lingshou County, with a mass coefficient K≥1.6 and a specific surface area≥420m². 2 / kg; the fly ash is Class I or II fly ash of F type, with a fineness of 8% and a water requirement of 92%; the red mud is produced by Anda Environmental Protection Technology Co., Ltd., and is Bayer process red mud, which needs to be thermally activated at 600-800℃ for 1-2 hours before use; the alkali activator is one or more of water glass, sodium hydroxide or sodium silicate. In a preferred embodiment of the present invention, the modified coal gangue aggregate is prepared by the following steps: The first batch of coal gangue is crushed into particles with a diameter of 0.1-5 mm by a crusher, and the second batch of coal gangue is crushed into particles with a diameter of 5-25 mm by a crusher. The two types of crushed particles are mixed and soaked in sodium hydroxide solution for 2-4 hours. After being taken out, they are heat-treated at 300-500℃ for 1-2 hours and then naturally cooled to 25℃ to obtain modified coal gangue aggregate.
[0007] In a preferred embodiment of the present invention, the ratio of the first part of coal gangue to the second part of coal gangue is 4-7g:8-11g; and the concentration of the sodium hydroxide solution is 0.5-1.5mol / L.
[0008] In a preferred embodiment of the present invention, the interface modifier is prepared by the following steps: Step a1: Add the nano silica dispersion, silane coupling agent, and ethanol solution to a three-necked flask equipped with a thermometer and a stirrer. Mix and stir at 300-500 r / min for 10-15 min. Adjust the pH to 3-4 with hydrochloric acid solution. Disperse at 5000 r / min for 30 min. Sonicate for 10-15 min. Heat in a water bath at 80℃ for 2 h. Cool naturally to 25℃. Wash 2-3 times with distilled water. Vacuum dry at 60℃ for 3-4 h to obtain modified silica. Step a2: Add the polymer emulsion and deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir and dilute at 200-300 rpm for 10-15 min. Add the alkaline etchant and mix and stir for 10-20 min. Add the modified silica dropwise to the three-necked flask at a rate of 2-3 mL / s and stir at 500-600 rpm for 5-10 min. Add the defoamer and continue stirring for 30 min. Adjust the pH to 8-9 with ammonia. Transfer the mixture to a high-shear homogenizer and homogenize at 10000 rpm for 5 min to obtain the interface modifier.
[0009] In a preferred embodiment of the present invention, the ratio of the nano-silica dispersion, silane coupling agent, and ethanol solution in step a1 is 30-50g: 4-8g: 100mL; the solid content of the nano-silica dispersion is 20-30%, and the particle size is 20-40nm; the silane coupling agent is KH-550; the mass fraction of the ethanol solution is 60-70%; and the concentration of the hydrochloric acid solution is 0.1mol / L.
[0010] In a preferred embodiment of the present invention, the ratio of the polymer emulsion, deionized water, alkaline etchant, modified silica, and defoamer in step a2 is 100-150 mL: 50-100 mL: 5-6 g: 30-35 g: 0.3-0.5 g; the polymer emulsion is styrene-acrylic emulsion BLJ-8600H with a solid content of 48-52%; the alkaline etchant is sodium metasilicate nonahydrate; the defoamer is SI-X101; and the ammonia water has a mass fraction of 25%.
[0011] In a preferred embodiment of the present invention, the reinforcing agent is prepared by the following steps: Step b1: Add sodium hydroxide and deionized water to a three-necked flask equipped with a thermometer and a stirrer, stir at 200-300 r / min for 30 min, cool naturally to 25℃, add water glass, and continue stirring for 10-15 min to obtain a compound alkali activator; add nano silica dispersion and polycarboxylate superplasticizer solution to a beaker, place in an ultrasonic disperser under ice-water bath conditions of 0-5℃, and sonicate at 40kHz frequency and 500W power for 15 min to obtain a pre-dispersion; add ultrafine fly ash and silica fume to a planetary ball mill, add early strength component, mix and grind at 300 r / min for 30 min to obtain activated mineral composite powder; Step b2: Add the compounded alkali activator to a three-necked flask equipped with a thermometer and a stirrer, and stir at 300 r / min for 10-15 min. Add the activated mineral composite powder and stir at 500 r / min for 15 min. Add the pre-dispersion liquid dropwise to the three-necked flask at a rate of 1-2 mL / s. Increase the stirring speed to 800 r / min and continue stirring for 30 min. Transfer the mixture to a colloid mill and cycle it 2-3 times at 3000 r / min to obtain the reinforcing agent.
[0012] In a preferred embodiment of the present invention, the dosage ratio of sodium hydroxide, deionized water, water glass, nano-silica dispersion, polycarboxylate superplasticizer solution, ultrafine fly ash, silica fume, and early strength component in step b1 is 10-15g: 50-60mL: 80-100g: 8-10mL: 2-3mL: 100-120g: 100-120g: 13-15g; the modulus of the water glass is 2.8-3.2, and the solid content is 35-40%; the solid content of the nano-silica dispersion is 30%, and the particle size is 20-40nm; the polycarboxylate superplasticizer solution is PCE-615, and the solid content is 40%; the specific surface area of the ultrafine fly ash is ≥600m². 2 / kg; the specific surface area of the silica fume is ≥15000m². 2 / kg; the early strength component is a mixture of triethanolamine and sodium sulfate in a mass ratio of 1:3.
[0013] In a preferred embodiment of the present invention, the ratio of the compound alkali activator, the activated mineral composite powder and the pre-dispersion liquid in step b2 is 150-175mL: 230-255g: 10-15mL.
[0014] Secondly, this application provides a method for preparing high-strength concrete made from all-solid waste modified coal gangue, comprising the following steps: Step 1: Weigh out 120-180 parts by weight of modified coal gangue aggregate, 50-100 parts by weight of cementitious material, 4-8 parts by weight of alkali activator, 2-5 parts by weight of interface modifier, 5-12 parts by weight of reinforcing agent, and 20-25 parts by weight of deionized water. Step 2: Add modified coal gangue aggregate and deionized water to a forced mixer and mix at 30-50 r / min for 3-5 min. Mix cementitious materials, alkali activator, interface modifier and reinforcing agent at 200-300 r / min for 2-3 min. After mixing, add to the forced mixer and continue mixing at 60 r / min for 2-3 min. Pour into shape and cure in a standard curing room at 25℃ and relative humidity ≥95% for 24 h to obtain high-strength concrete made from all-solid waste modified coal gangue.
[0015] The beneficial effects of this invention are: This invention discloses a high-strength concrete made from modified coal gangue and its preparation method. The method involves adding modified coal gangue aggregate and deionized water to a forced mixer for mixing; then adding a mixture of cementitious materials, an alkali activator, an interface modifier, and a reinforcing agent to the forced mixer, continuing mixing, pouring and curing the mixture to obtain the high-strength concrete. Through the surface activation treatment of the modified coal gangue aggregate and the synergistic effect of the interface modifier and reinforcing agent, the aggregate-slurry interface bonding force is significantly improved, and the hydration process of the cementitious materials is optimized, achieving high-value utilization of all solid waste and enhancing the mechanical properties and durability of the concrete.
[0016] In the preparation of a high-strength concrete made from modified coal gangue, modified coal gangue aggregate was first prepared. The coal gangue aggregate was surface activated by a composite modification method combining alkaline immersion and heat treatment. On the one hand, alkaline etching roughened the surface of the aggregate, increasing the mechanical bonding force with the cementitious material; on the other hand, heat treatment generated active aluminosilicate minerals on the surface of the aggregate, which could chemically bond with the cementitious material and significantly improve the structure of the interface transition zone.
[0017] In the preparation of a high-strength concrete made from modified coal gangue (all solid waste), an interface modifier was first prepared. A silane coupling agent hydrolyzed under acidic conditions, converting siloxyethyl groups into silanol groups, generating reactive silanol groups. The surface of nano-silica is rich in silanol groups. The hydrolyzed silanols condensed with the hydroxyl groups on the nano-silica surface to form siloxane bonds. The organic functional group amino groups were chemically bonded to the surface of nano-silica, organically modifying the surface of the nanoparticles and forming core-shell structured organic-inorganic hybrid particles. Sodium metasilicate nonahydrate, after hydrolysis in water, became alkaline, etching the surface of the coal gangue aggregate and modifying the carbon dioxide. The amino groups on the silicon dioxide surface interact with the carboxyl groups in the styrene-acrylic emulsion via ionic interactions / hydrogen bonds, forming a physical cross-linking network and thus an interface modifier, improving the stability of the composite system. Modified silica provides chemical bonding sites, and the polymer emulsion forms a transition layer. Together, they synergistically enhance the aggregate-slurry interface. The alkaline etchant forms micro-pits on the aggregate surface, increasing physical interlocking force and allowing the slurry to better embed into the aggregate surface. Modified silica penetrates into the micropores on the aggregate surface, filling defects and simultaneously acting as a nucleus to induce the growth of hydration products at the interface. After the polymer emulsion forms a film, it creates a flexible interface layer that buffers shrinkage stress and reduces the generation of microcracks.
[0018] In the preparation of a high-strength concrete made from all-solid waste modified coal gangue, a reinforcing agent was first prepared. Sodium hydroxide and water glass were combined to obtain a low-modulus composite alkali activator; OH -The silicon-oxygen network in water glass is disrupted to generate active silicate ions, providing a highly alkaline environment for subsequent geological polymerization reactions. Nano-silica is ultrasonically dispersed with the assistance of a polycarboxylate superplasticizer to obtain a pre-dispersed liquid, preventing agglomeration and improving stability. Ultrafine fly ash, silica fume, and early-strength components are ball-milled and activated to obtain activated mineral composite powder. The fly ash is then processed in OH... - Under the influence of the action, aluminate ions are released, mechanical force causes lattice distortion and fresh fracture surfaces on the surface of mineral particles, triethanolamine acts as a surfactant to promote mineral dissolution, and sodium sulfate provides SO4. 2- Accelerating the formation of ettringite, all three components work together to enhance the mineral's reactivity. When the aforementioned compound alkali activator, activated mineral composite powder, and pre-dispersion liquid are mixed, the active silicate and aluminate ions react with the CaO on the surface of the activated minerals. 2+ Al 3+ A pre-hydration reaction occurs, generating a gel precursor in which nano-silica is dispersed as crystal nuclei, thus becoming a reinforcing agent. The alkali activator effectively disrupts the glassy structure in the solid waste, promoting the dissolution of active silica and alumina, and accelerating the geopolymerization reaction. Nano-silica provides highly active crystal nuclei, inducing the directional growth of hydration products at the interface, refining the pore structure, and improving the matrix density. Ultrafine fly ash and silica fume form a micro-aggregate filling system with a continuous particle size distribution, optimizing the particle packing density. In the early strength component, triethanolamine accelerates the mineral hydration in the cementitious material, and sodium sulfate promotes the formation of ettringite, achieving early strength enhancement. Detailed Implementation
[0019] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. 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.
[0020] Example 1:
[0021] This embodiment describes a method for preparing high-strength concrete made from all-solid waste modified coal gangue, comprising the following steps: Step S1: The first 4g of coal gangue was crushed into particles with a diameter of 0.1mm using a crusher, and the second 8g of coal gangue was crushed into particles with a diameter of 5mm using a crusher. The two types of crushed particles were mixed and soaked in a 0.5mol / L sodium hydroxide solution for 2 hours. After being removed, the mixture was heat-treated at 300℃ for 1 hour and then naturally cooled to 25℃ to obtain modified coal gangue aggregate. The coal gangue was obtained from Yumei Bulk Coal Technology Co., Ltd. Step S2: Add 30g of nano-silica dispersion with a solid content of 20% and a particle size of 20nm, 4g of silane coupling agent KH-550, and 100mL of ethanol solution with a mass fraction of 60% to a three-necked flask equipped with a thermometer and a stirrer. Mix and stir at 300r / min for 10min. Adjust the pH to 3 with 0.1mol / L hydrochloric acid solution. Disperse at 5000r / min for 30min. Sonicate for 10min. Heat in a water bath at 80℃ for 2h. Cool naturally to 25℃. Wash twice with distilled water. Vacuum dry at 60℃ for 3h to obtain modified silica. Step S3: Add 100 mL of 48% styrene-acrylic emulsion BLJ-8600H and 50 mL of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir and dilute at 200 r / min for 10 min. Add 5 g of sodium metasilicate nonahydrate and mix and stir for 10 min. Add 30 g of modified silica dropwise to the above three-necked flask at a rate of 2 mL / s. Stir at 500 r / min for 5 min. Add 0.3 g of defoamer SI-X101 and continue stirring for 30 min. Adjust the pH to 8 with 25% ammonia water. Transfer to a high-shear homogenizer and homogenize at 10000 r / min for 5 min to obtain the interface modifier. Step S4: Add 10g of sodium hydroxide and 50mL of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir at 200r / min for 30min, allow to cool naturally to 25℃, add 80g of water glass with a modulus of 2.8 and a solid content of 35%, and continue stirring for 10min to obtain a compound alkali activator. Add 8mL of nano-silica dispersion with a solid content of 30% and a particle size of 20nm and 2mL of polycarboxylate superplasticizer solution with a solid content of 40% and model PCE-615 to a beaker. Place the beaker in an ultrasonic disperser under an ice-water bath at 0℃ and ultrasonically treat it at a frequency of 40kHz and a power of 500W for 15min to obtain a pre-dispersion. Add 100g of ultrafine fly ash and 100g of silica fume to a planetary ball mill, add 13g of early strength component, and mix and grind at 300r / min for 30min to obtain activated mineral composite powder. Step S5: Add 150 mL of compound alkali activator to a three-necked flask equipped with a thermometer and a stirrer, stir at 300 r / min for 10 min, add 230 g of activated mineral composite powder, stir at 500 r / min for 15 min, add 10 mL of pre-dispersion liquid dropwise to the above three-necked flask at a speed of 1 mL / s, increase the stirring speed to 800 r / min and continue stirring for 30 min, transfer to a colloid mill, and cycle twice at 3000 r / min to obtain the reinforcing agent; Step S6: Weigh out 120 parts by weight of modified coal gangue aggregate, 50 parts by weight of cementitious material, 4 parts by weight of water glass, 2 parts by weight of interface modifier, 5 parts by weight of reinforcing agent, and 20 parts by weight of deionized water; the cementitious material is composed of 50 parts by weight of slag, 20 parts by weight of fly ash, and 15 parts by weight of red mud, with a specific surface area ≥ 450 m². 2 / kg; the modulus of the water glass is 2.8 and the solid content is 35%; the slag is in powder form, produced by Lingshou County Fengfeng Mineral Products Processing Plant, with a mass coefficient K=1.8 and a specific surface area of 420m². 2 / kg; the fly ash is Class I F fly ash with a fineness of 8% and a water requirement of 92%; the red mud is produced by Anda Environmental Protection Technology Co., Ltd., and is Bayer process red mud, which is thermally activated at 600℃ for 1 hour before use; Step S7: Add modified coal gangue aggregate and deionized water to a forced mixer and mix at 30 r / min for 3 min; mix cementitious materials, alkali activator, interface modifier and reinforcing agent and mix at 200 r / min for 2 min. After mixing, add to the forced mixer and continue mixing at 60 r / min for 2 min. Pour into shape and cure in a standard curing room at 25℃ and relative humidity ≥95% for 24 h to obtain high-strength concrete made from all-solid waste modified coal gangue.
[0022] Example 2:
[0023] This embodiment describes a method for preparing high-strength concrete made from all-solid waste modified coal gangue, comprising the following steps: Step S1: The first 5.5g of coal gangue was crushed into particles with a diameter of 3mm using a crusher, and the second 9.5g of coal gangue was crushed into particles with a diameter of 15mm using a crusher. The two particle sizes were mixed and soaked in a 1mol / L sodium hydroxide solution for 3 hours. After being removed, the mixture was heat-treated at 400℃ for 1.5 hours and then naturally cooled to 25℃ to obtain modified coal gangue aggregate. The coal gangue was obtained from Yumei Bulk Coal Technology Co., Ltd. Step S2: Add 40g of nano-silica dispersion with a solid content of 25% and a particle size of 30nm, 6g of silane coupling agent KH-550, and 100mL of ethanol solution with a mass fraction of 65% to a three-necked flask equipped with a thermometer and a stirrer. Mix and stir at 400r / min for 13min. Adjust the pH to 3 with 0.1mol / L hydrochloric acid solution. Disperse at 5000r / min for 30min. Sonicate for 13min. Heat in a water bath at 80℃ for 2h. Cool naturally to 25℃. Wash three times with distilled water. Vacuum dry at 60℃ for 3.5h to obtain modified silica. Step S3: Add 125 mL of 50% styrene-acrylic emulsion BLJ-8600H and 75 mL of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir and dilute at 250 r / min for 13 min. Add 5.5 g of sodium metasilicate nonahydrate and mix and stir for 15 min. Add 33 g of modified silica dropwise to the above three-necked flask at a rate of 2.5 mL / s. Stir at 550 r / min for 8 min. Add 0.4 g of defoamer SI-X101 and continue stirring for 30 min. Adjust the pH to 8.5 with 25% ammonia water. Transfer to a high-shear homogenizer and homogenize at 10000 r / min for 5 min to obtain the interface modifier. Step S4: Add 13g of sodium hydroxide and 55mL of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir at 250r / min for 30min, allow to cool naturally to 25℃, add 90g of water glass with a modulus of 3 and a solid content of 38%, and continue stirring for 13min to obtain a compound alkali activator. Add 9mL of nano-silica dispersion with a solid content of 30% and a particle size of 30nm and 2.5mL of polycarboxylate superplasticizer solution with a solid content of 40% and model PCE-615 to a beaker. Place the beaker in an ultrasonic disperser under an ice-water bath at 3℃ and ultrasonically treat it at a frequency of 40kHz and a power of 500W for 15min to obtain a pre-dispersion. Add 110g of ultrafine fly ash and 110g of silica fume to a planetary ball mill, add 14g of early strength component, and mix and grind at 300r / min for 30min to obtain activated mineral composite powder. Step S5: Add 160 mL of compound alkali activator to a three-necked flask equipped with a thermometer and a stirrer, stir at 300 r / min for 13 min, add 245 g of activated mineral composite powder, stir at 500 r / min for 15 min, add 13 mL of pre-dispersion liquid dropwise to the above three-necked flask at a speed of 1.5 mL / s, increase the stirring speed to 800 r / min and continue stirring for 30 min, transfer to a colloid mill, and cycle the treatment 3 times at a speed of 3000 r / min to obtain the reinforcing agent; Step S6: Weigh out 150 parts by weight of modified coal gangue aggregate, 75 parts by weight of cementitious material, 6 parts by weight of alkali activator, 3 parts by weight of interface modifier, 8 parts by weight of reinforcing agent, and 23 parts by weight of deionized water; the cementitious material is composed of 55 parts by weight of slag, 25 parts by weight of fly ash, and 20 parts by weight of red mud, with a specific surface area ≥ 450 m². 2 / kg; the modulus of the water glass is 2.8 and the solid content is 35%; the slag is in powder form, produced by Lingshou County Fengfeng Mineral Products Processing Plant, with a mass coefficient K=1.8 and a specific surface area of 420m². 2 / kg; The fly ash is Class I F fly ash with a fineness of 8% and a water requirement of 92%; The red mud is produced by Anda Environmental Protection Technology Co., Ltd., and is Bayer process red mud, which is thermally activated at 700℃ for 1 hour before use; Step S7: Add modified coal gangue aggregate and deionized water to a forced mixer and mix at 40 r / min for 4 min; mix cementitious materials, alkali activator, interface modifier and reinforcing agent and mix at 250 r / min for 3 min; after mixing, add to the forced mixer and continue mixing at 60 r / min for 3 min; pour into molds and cure in a standard curing room at 25℃ and relative humidity ≥95% for 24 h to obtain high-strength concrete made from all-solid waste modified coal gangue.
[0024] Example 3:
[0025] This embodiment describes a method for preparing high-strength concrete made from all-solid waste modified coal gangue, comprising the following steps: Step S1: The first 7g of coal gangue was crushed into particles with a diameter of 5mm using a crusher, and the second 11g of coal gangue was crushed into particles with a diameter of 25mm using a crusher. The two types of crushed particles were mixed and soaked in a 1.5mol / L sodium hydroxide solution for 4 hours. After being removed, the mixture was heat-treated at 500℃ for 2 hours and then naturally cooled to 25℃ to obtain modified coal gangue aggregate. The coal gangue was obtained from Yumei Bulk Coal Technology Co., Ltd. Step S2: Add 50g of nano-silica dispersion with a solid content of 30% and a particle size of 40nm, 8g of silane coupling agent KH-550, and 100mL of 70% ethanol solution to a three-necked flask equipped with a thermometer and a stirrer. Mix and stir at 500r / min for 15min. Adjust the pH to 4 with 0.1mol / L hydrochloric acid solution. Disperse at 5000r / min for 30min. Sonicate for 15min. Heat in a water bath at 80℃ for 2h. Cool naturally to 25℃. Wash three times with distilled water. Vacuum dry at 60℃ for 4h to obtain modified silica. Step S3: Add 150 mL of 52% styrene-acrylic emulsion BLJ-8600H and 100 mL of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir and dilute at 300 r / min for 15 min. Add 6 g of sodium metasilicate nonahydrate and mix and stir for 20 min. Add 35 g of modified silica dropwise to the above three-necked flask at a rate of 3 mL / s. Stir at 600 r / min for 10 min. Add 0.5 g of defoamer SI-X101 and continue stirring for 30 min. Adjust the pH to 9 with 25% ammonia water. Transfer to a high-shear homogenizer and homogenize at 10000 r / min for 5 min to obtain the interface modifier. Step S4: Add 15g of sodium hydroxide and 60mL of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir at 300r / min for 30min, allow to cool naturally to 25℃, add 100g of water glass with a modulus of 3.2 and a solid content of 40%, and continue stirring for 15min to obtain a compound alkali activator. Add 10mL of nano-silica dispersion with a solid content of 30% and a particle size of 40nm and 3mL of polycarboxylate superplasticizer solution with a solid content of 40% and model PCE-615 to a beaker. Place the beaker in an ultrasonic disperser under an ice-water bath at 5℃ and ultrasonically treat it at a frequency of 40kHz and a power of 500W for 15min to obtain a pre-dispersion. Add 120g of ultrafine fly ash and 120g of silica fume to a planetary ball mill, add 15g of early strength component, and mix and grind at 300r / min for 30min to obtain activated mineral composite powder. Step S5: Add 175 mL of compound alkali activator to a three-necked flask equipped with a thermometer and a stirrer, stir at 300 r / min for 15 min, add 255 g of activated mineral composite powder, stir at 500 r / min for 15 min, add 15 mL of pre-dispersion liquid dropwise to the above three-necked flask at a speed of 2 mL / s, increase the stirring speed to 800 r / min and continue stirring for 30 min, transfer to a colloid mill, and cycle the treatment 3 times at a speed of 3000 r / min to obtain the reinforcing agent; Step S6: Weigh out 180 parts by weight of modified coal gangue aggregate, 100 parts by weight of cementitious material, 8 parts by weight of alkali activator, 5 parts by weight of interface modifier, 12 parts by weight of reinforcing agent, and 25 parts by weight of deionized water; the cementitious material is composed of 60 parts by weight of slag, 30 parts by weight of fly ash, and 25 parts by weight of red mud, with a specific surface area ≥ 450 m². 2 / kg; the modulus of the water glass is 2.8 and the solid content is 35%; the slag is in powder form, produced by Lingshou County Fengfeng Mineral Products Processing Plant, with a mass coefficient K=1.8 and a specific surface area of 420m². 2 / kg; the fly ash is Class I F fly ash with a fineness of 8% and a water requirement of 92%; the red mud is produced by Anda Environmental Protection Technology Co., Ltd., and is Bayer process red mud, which is thermally activated at 800℃ for 1 hour before use; Step S7: Add modified coal gangue aggregate and deionized water to a forced mixer and mix at 50 r / min for 5 min; mix cementitious materials, alkali activator, interface modifier and reinforcing agent and mix at 300 r / min for 3 min. After mixing, add to the forced mixer and continue mixing at 60 r / min for 3 min. Pour into shape and cure in a standard curing room at 25℃ and relative humidity ≥95% for 24 h to obtain high-strength concrete made from all-solid waste modified coal gangue.
[0026] Comparative Example 1: This comparative example illustrates a method for preparing high-strength concrete made from all-solid waste modified coal gangue, comprising the following steps: Step S1: The first 5.5g of coal gangue is crushed into particles with a diameter of 3mm using a crusher, and the second 9.5g of coal gangue is crushed into particles with a diameter of 15mm using a crusher. The two particle sizes are mixed and soaked in a 1mol / L sodium hydroxide solution for 3 hours. After removal, it is heat-treated at 400℃ for 1.5 hours and then naturally cooled to 25℃ to obtain modified coal gangue aggregate. 20 parts of red mud are thermally activated at 700℃ for 2 hours. 20 parts of the treated red mud, 55 parts of slag, and 25 parts of fly ash are mixed and ground together to a specific surface area of 480m² / kg to obtain a cementitious material. The coal gangue is sourced from Yumei Bulk Technology Co., Ltd.; the slag is powdered and sourced from Lingshou County Fengfeng Mineral Products Processing Plant, with a mass coefficient K=1.8 and a specific surface area of 420m² / kg. 2 / kg; the fly ash is Class I F fly ash with a fineness of 8% and a water requirement ratio of 92%; the red mud is produced by Anda Environmental Protection Technology Co., Ltd., and is Bayer process red mud; Step S2: Take 100 parts of modified coal gangue aggregate, 30 parts of cementitious material, 5 parts of water glass, and 12 parts of deionized water according to the proportion; first, add the modified coal gangue aggregate and cementitious material to a forced mixer and dry mix for 1 minute, then add the water glass and deionized water, and mix at 40 r / min for 4 minutes to obtain a concrete mixture; pour the concrete mixture into test blocks and vibrate to compact it, demold after 24 hours, and cure at a standard temperature of 25℃ and relative humidity of 95% for 24 hours to obtain high-strength concrete made from all-solid waste modified coal gangue; the modulus of the water glass is 2.8 and the solid content is 35%.
[0027] Comparative Example 2: This comparative example illustrates a method for preparing high-strength concrete made from all-solid waste modified coal gangue, comprising the following steps: Step S1: The first 5.5g of coal gangue was crushed into particles with a diameter of 3mm using a crusher, and the second 9.5g of coal gangue was crushed into particles with a diameter of 15mm using a crusher. The two particle sizes were mixed and soaked in a 1mol / L sodium hydroxide solution for 3 hours. After removal, the mixture was heat-treated at 300℃ for 1.5 hours and then naturally cooled to 25℃ to obtain modified coal gangue aggregate. Red mud was thermally activated at 700℃ for 2 hours. 20 parts of the treated red mud, 55 parts of slag, and 25 parts of fly ash were mixed and ground together to a specific surface area of 480m² / kg to obtain a cementitious material. The coal gangue was obtained from Yumei Bulk Technology Co., Ltd.; the slag was powdered and processed by Lingshou County Fengfeng Mineral Products Processing Plant, with a mass coefficient K=1.8 and a specific surface area of 420m² / kg. 2 / kg; the fly ash is Class I F fly ash with a fineness of 8% and a water requirement ratio of 92%; the red mud is produced by Anda Environmental Protection Technology Co., Ltd., and is Bayer process red mud; Step S2: Take 100 parts of modified coal gangue aggregate, 30 parts of cementitious material, 5 parts of water glass, and 12 parts of deionized water according to the proportion; first, add the modified coal gangue aggregate and cementitious material to a forced mixer and dry mix for 1 minute, then add the water glass and deionized water, and mix at 40 r / min for 4 minutes to obtain a concrete mixture; pour the concrete mixture into test blocks and vibrate to compact it, demold after 24 hours, and cure at a standard temperature of 25℃ and relative humidity of 95% for 24 hours to obtain high-strength concrete made from all-solid waste modified coal gangue; the modulus of the water glass is 2.8 and the solid content is 35%.
[0028] Comparative Example 3: This comparative example illustrates a method for preparing high-strength concrete made from all-solid waste modified coal gangue, comprising the following steps: Step S1: The first portion of 5.5g of coal gangue is crushed into particles with a diameter of 3mm using a crusher. The second portion of 9.5g of coal gangue is crushed into particles with a diameter of 15mm using a crusher. The two particle sizes are mixed to obtain coal gangue aggregate. Red mud is thermally activated at 700℃ for 2 hours. 20 parts of the activated red mud, 55 parts of slag, and 25 parts of fly ash are mixed and ground together until the specific surface area is 480m² / kg to obtain a cementitious material. The coal gangue is sourced from Yumei Bulk Technology Co., Ltd. The slag is in powder form and sourced from Lingshou County Fengfeng Mineral Products Processing Plant, with a mass coefficient K=1.8 and a specific surface area of 420m² / kg. 2 / kg; the fly ash is Class I F fly ash with a fineness of 8% and a water requirement ratio of 92%; the red mud is produced by Anda Environmental Protection Technology Co., Ltd., and is Bayer process red mud; Step S2: Take 100 parts of coal gangue aggregate, 30 parts of cementitious material, 5 parts of water glass, and 12 parts of deionized water according to the proportion; first, add the modified coal gangue aggregate and cementitious material to a forced mixer and dry mix for 1 minute, then add water glass and deionized water, and mix at 40 r / min for 4 minutes to obtain a concrete mixture; pour the concrete mixture into test blocks and vibrate to compact it, demold after 24 hours, and cure at a standard temperature of 25℃ and relative humidity of 95% for 24 hours to obtain high-strength concrete made from all-solid waste modified coal gangue; the modulus of the water glass is 2.8 and the solid content is 35%.
[0029] The high-strength concrete made from all-solid waste modified coal gangue prepared in Examples 1-3 and Comparative Examples 1-3 were tested according to the specimen preparation method, curing method, and strength testing method in GB / T17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)". Performance testing was conducted according to GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete". The test results are shown in the table below.
[0030] Comparing Examples 1-3 with Comparative Examples 1-3: In Examples 1-3, increasing the alkali treatment concentration from 0.5 mol / L to 1.5 mol / L and the heat treatment temperature from 300℃ to 500℃ increased the leaching of active SiO2 and Al2O3 on the surface of the coal gangue aggregate, enhancing interfacial chemical activity; simultaneously, the proportion of coarse aggregate in the aggregate particle size distribution increased, forming a better dense skeleton structure. The combined effect of these two factors resulted in a denser interfacial transition zone in the concrete and improved overall strength. Comparing Example 2 with Comparative Examples 1-3... It can be seen that: Example 2 uses both interface modifier and reinforcing agent for dual modification, and the aggregate undergoes complete alkali soaking and heat treatment activation, forming a synergistic reinforcement system of "interface strengthening - bulk density - aggregate activation"; while Comparative Example 1 uses the same aggregate gradation and activation treatment, but completely lacks interface modifier and reinforcing agent; Comparative Example 2 further reduced the aggregate heat treatment temperature, resulting in insufficient activation; Comparative Example 3 did not perform alkali soaking and heat treatment on the aggregate at all, the aggregate surface was smooth and inactive, and the interfacial bonding force was the worst.
[0031] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., 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.
[0032] The above description is merely an example and illustration 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 invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.
Claims
1. A high-strength concrete made entirely from modified coal gangue, characterized in that, Includes the following components by weight: 120-180 parts modified coal gangue aggregate, 50-100 parts cementitious material, 4-8 parts alkali activator, 2-5 parts interface modifier, 5-12 parts reinforcing agent, and 20-25 parts deionized water; The modified coal gangue aggregate is prepared by the following steps: The first batch of coal gangue was crushed into particles with a diameter of 0.1-5 mm by a crusher, and the second batch of coal gangue was crushed into particles with a diameter of 5-25 mm by a crusher. The two types of coal gangue particles with the above-mentioned crushed particle sizes were mixed and soaked in sodium hydroxide solution. After being taken out, they were heat-treated and cooled to obtain modified coal gangue aggregate.
2. The high-strength concrete made from all-solid waste modified coal gangue according to claim 1, characterized in that, The cementitious material is composed of 50-60 parts slag, 20-30 parts fly ash, and 15-25 parts red mud, with a specific surface area ≥450m². 2 / kg; the slag is in powder form, with a mass coefficient K ≥ 1.6 and a specific surface area ≥ 420m². 2 / kg; the fly ash is Class I or II fly ash of type F, with a fineness of 8% and a water requirement of 92%; the red mud is Bayer process red mud, which needs to be thermally activated at 600-800℃ for 1-2 hours before use; the alkali activator is one or more combinations of water glass, sodium hydroxide or sodium silicate.
3. The high-strength concrete made from all-solid waste modified coal gangue according to claim 1, characterized in that, The ratio of the first part of coal gangue to the second part of coal gangue is 4-7g:8-11g; the concentration of the sodium hydroxide solution is 0.5-1.5mol / L.
4. The high-strength concrete made from all-solid waste modified coal gangue according to claim 1, characterized in that, The interface modifier is prepared by the following steps: Step a1: Mix and stir the nano silica dispersion, silane coupling agent and ethanol solution, adjust the pH with hydrochloric acid solution, stir and disperse, sonicate, heat in water bath, cool naturally, wash and dry to obtain modified silica; Step a2: Mix and dilute the polymer emulsion and deionized water, add alkaline etchant, mix and stir, add modified silica, mix and stir, add defoamer, continue stirring, adjust pH with ammonia, transfer to a high shear homogenizer for homogenization, and obtain interface modifier.
5. The high-strength concrete made from all-solid waste modified coal gangue according to claim 4, characterized in that, In step a1, the ratio of the nano-silica dispersion, silane coupling agent, and ethanol solution is 30-50g: 4-8g: 100mL; the solid content of the nano-silica dispersion is 20-30%, and the particle size is 20-40nm; the silane coupling agent is KH-550; the mass fraction of the ethanol solution is 60-70%; and the concentration of the hydrochloric acid solution is 0.1mol / L.
6. The high-strength concrete made from all-solid waste modified coal gangue according to claim 4, characterized in that, In step a2, the ratio of the polymer emulsion, deionized water, alkaline etchant, modified silica, and defoamer is 100-150 mL: 50-100 mL: 5-6 g: 30-35 g: 0.3-0.5 g; the polymer emulsion is styrene-acrylic emulsion BLJ-8600H with a solid content of 48-52%; the alkaline etchant is sodium metasilicate nonahydrate; the defoamer is SI-X101; and the ammonia water has a mass fraction of 25%.
7. The high-strength concrete made from all-solid waste modified coal gangue according to claim 1, characterized in that, The reinforcing agent is prepared by the following steps: Step b1: Mix sodium hydroxide and deionized water, stir, cool naturally, add water glass, and continue stirring to obtain a compound alkali activator; add nano silica dispersion and polycarboxylate superplasticizer solution to a beaker, and sonicate under ice-water bath conditions to obtain a pre-dispersion; Ultrafine fly ash and silica fume are added to a planetary ball mill, along with an early-strength component, and then mixed and ground to obtain activated mineral composite powder. Step b2: Mix the compound alkali activator and activated mineral composite powder, add the pre-dispersion liquid, continue stirring, and transfer to a colloid mill for processing to obtain the reinforcing agent.
8. The high-strength concrete made from all-solid waste modified coal gangue according to claim 7, characterized in that, In step b1, the dosage ratio of sodium hydroxide, deionized water, water glass, nano-silica dispersion, polycarboxylate superplasticizer solution, ultrafine fly ash, silica fume, and early-strength component is 10-15g: 50-60mL: 80-100g: 8-10mL: 2-3mL: 100-120g: 100-120g: 13-15g; the water glass has a modulus of 2.8-3.2 and a solid content of 35-40%; the nano-silica dispersion has a solid content of 30% and a particle size of 20-40nm; the polycarboxylate superplasticizer solution is PCE-615 with a solid content of 40%; and the ultrafine fly ash has a specific surface area ≥600m². 2 / kg; the specific surface area of the silica fume is ≥15000m². 2 / kg; the early strength component is a mixture of triethanolamine and sodium sulfate in a mass ratio of 1:
3.
9. A high-strength concrete made from all-solid waste modified coal gangue according to claim 7, characterized in that, The ratio of the compound alkali activator, activated mineral composite powder and pre-dispersion liquid in step b2 is 150-175mL: 230-255g: 10-15mL.
10. A method for preparing high-strength concrete made from all-solid waste modified coal gangue as described in any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Weigh out 120-180 parts of modified coal gangue aggregate, 50-100 parts of cementitious material, 4-8 parts of alkali activator, 2-5 parts of interface modifier, 5-12 parts of reinforcing agent, and 20-25 parts of deionized water according to the following weight proportions. Step 2: Add modified coal gangue aggregate and deionized water to a forced mixer and mix; mix cementitious materials, alkali activator, interface modifier and reinforcing agent, add the mixture to the forced mixer and continue mixing, pour into shape, and cure to obtain high-strength concrete made from all-solid waste modified coal gangue.