Coal gangue-based ceramic tile adhesive for thin-layer paving and preparation method of coal gangue-based ceramic tile adhesive

Abstract

The invention discloses a coal gangue-based ceramic tile adhesive for thin-layer paving and a preparation method of the coal gangue-based ceramic tile adhesive, and belongs to the technical field of adhesives. Comprising the following raw materials: 450-550 parts of composite coal gangue powder, 250-300 parts of ordinary Portland cement, 15-20 parts of copolymer rubber powder, 1-2 parts of hydroxypropyl methyl cellulose, 0.2-0.5 part of starch ether, 5-8 parts of sodium formate, 8-10 parts of reinforced fibers, 10-15 parts of an early strength agent and 180-200 parts of water. Coal gangue powder is subjected to decarburization treatment, reaction activity is improved, the coal gangue powder is adsorbed in filling pores of phase change microcapsules to reduce the water absorption rate and enhance the mechanical property and durability, then a silane coupling agent KH570 solution is used for modification, the water resistance is optimized, and tetrapod-like zinc oxide enhanced fibers, cement, rubber powder and the like are matched to achieve the synergistic effect, so that the waterproof performance is improved. The coal gangue-based ceramic tile adhesive for thin-layer paving is obtained, and the environmental protection and performance requirements are both considered.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to a coal gangue-based ceramic brick adhesive for thin-layer paving and its preparation method. Background Technology

[0002] Coal gangue is a solid waste generated during coal mining and washing. Its long-term accumulation not only occupies vast amounts of land resources but also easily leads to environmental pollution and ecological risks. To implement a circular economy development model, the building materials industry is actively exploring efficient resource utilization pathways for bulk solid waste. Among these, using treated coal gangue to replace some cement-based cementitious materials and developing new green building materials has become a key breakthrough in promoting the industry's low-carbon transformation and high-value utilization of solid waste.

[0003] Traditional ceramic tile adhesives use cement as the main binder, resulting in significant energy consumption and carbon emissions during production. In contrast, coal gangue-based ceramic tile adhesives, as a novel green paving material, are innovative in that they utilize activated coal gangue powder as a key mineral admixture to partially replace cement, and are formulated with composite aggregates, redispersible latex powder, cellulose ethers, and other polymer additives. This technological approach effectively reduces cement usage and provides a new approach to energy conservation and emission reduction in the building materials industry.

[0004] Because coal gangue powder is used as a base material, it is prone to generating numerous microcracks and porous structures during its crushing and processing, resulting in a significantly high water absorption rate. This characteristic leads to increased drying shrinkage of coal gangue-based ceramic brick adhesives, easily inducing transverse shear cracking. Furthermore, after hydration of the coal gangue-silicate composite system, the internal porous solution is highly susceptible to instantaneous freezing near 0°C, generating significant expansion stress and easily triggering freeze-thaw cracks and interface voids. Especially in outdoor thin-layer paving applications, the freeze-thaw resistance of coal gangue-based ceramic brick adhesives deteriorates significantly, greatly increasing the risk of brick detachment.

[0005] Therefore, how to effectively improve the freeze-thaw resistance of coal gangue-silicate system ceramic tile adhesives and block the initiation and propagation of frost heave cracks has become a key research direction for reducing the risk of outdoor thin-layer ceramic tile detachment. Summary of the Invention

[0006] The purpose of this invention is to provide an adhesive for thin-layer paving of coal gangue-based ceramic bricks and its preparation method. Ultrafine sodium-based montmorillonite is used as a buffer phase, and phase change microcapsules are mixed into decarburized coal gangue powder. The phase change microcapsules of n-alkane core material release latent heat during the initial setting of the adhesive, which compensates for its early strength performance and reduces its frost heave stress, inhibits crack propagation, and improves the durability of outdoor thin-layer paved ceramic bricks.

[0007] The objective of this invention can be achieved through the following technical solutions: An adhesive for thin-layer paving of coal gangue-based ceramic bricks, comprising the following raw materials by weight: The mixture consists of 450-550 parts of composite coal gangue powder, 250-300 parts of ordinary silicate cement, 15-20 parts of copolymer adhesive powder, 1-2 parts of hydroxypropyl methylcellulose, 0.2-0.5 parts of starch ether, 5-8 parts of sodium formate, 8-10 parts of reinforcing fiber, 10-15 parts of early strength agent, and 180-200 parts of water.

[0008] Furthermore, the composite coal gangue powder is prepared through the following steps: Using ultrafine sodium-based montmorillonite as a buffer phase, phase change microcapsules containing n-alkane core material were combined with decarbonized coal gangue powder, and then modified with silane coupling agent KH570 to obtain composite coal gangue powder.

[0009] Furthermore, the n-alkane is any one of n-heptadecane, n-octadecane, and n-nonadecanane.

[0010] Furthermore, the specific preparation steps of the phase change microcapsules are as follows: n-Alkanes and formamide were added to a three-necked flask and stirred at 350-450 rpm and 55-65°C for 30-40 min. Then hexadecyltrimethylammonium bromide was added and stirred for 5-6 h. Tetraethyl silicate was added and stirred for 4-5 h. 2 wt% hydrochloric acid was added dropwise at 800 μL / min. After the addition was complete, the mixture was stirred for 5-6 h and kept at this temperature for 24-36 h. The mixture was then filtered, washed, and dried to obtain phase change microcapsules.

[0011] Furthermore, the ratio of n-alkanes, formamide, hexadecyltrimethylammonium bromide, tetraethyl silicate, and 2wt% hydrochloric acid is 50-60g: 750-900mL: 10-12g: 50-60g: 750-900mL.

[0012] Furthermore, the specific preparation steps of the composite coal gangue powder are as follows: Phase change microcapsules and ultrafine sodium-based montmorillonite were mixed evenly and then added to decarburized coal gangue powder. The mixture was stirred at 350-450 rpm for 10-20 min, transferred to a 5 wt% solution of silane coupling agent KH570, soaked at 70-80℃ for 5-6 h, filtered, and dried to constant weight to obtain composite coal gangue powder.

[0013] Furthermore, the ratio of phase change microcapsules, ultrafine sodium-based montmorillonite, decarburized coal gangue powder, and 5 wt% silane coupling agent KH570 solution is 50~60g:10~15g:500~600g:10~12L.

[0014] Furthermore, the decarbonized coal gangue powder is prepared through the following steps: Add the coal gangue powder that has passed through a 100-mesh sieve into a ball mill and ball mill it at 500-600 rpm for 3-4 hours. Then transfer it to a muffle furnace and calcine it at 800-900℃ for 4-5 hours at 5℃ / min to obtain decarburized coal gangue powder. Furthermore, the specific preparation steps for the reinforced fiber are as follows: The fiber was added to an 80wt% aqueous ethanol solution, and then silane coupling agent KH550 was added. The mixture was stirred at 80~90℃ for 3~4h, filtered, and the product was washed with deionized water and ethanol 3~5 times. The product was then freeze-dried to obtain the modified fiber. Zinc acetate dihydrate and sodium hydroxide were added to ethanol and stirred at 25-35°C for 30-40 min. The mixture was then sonicated at 60-70°C for 35-45 min. Modified fibers were then added and soaked for 30-40 min. The mixture was filtered and heated at 150-160°C for 10-20 min. The soaking and heating process was repeated 5-8 times to obtain the fiber precursor. Zinc chloride, hexamethylenetetramine, and silver nitrate were added to distilled water and stirred for 5-10 minutes. Then, fiber precursors were added, the container was sealed, and the mixture was heated to 130-150°C at a rate of 5°C / min and kept at that temperature for 6-8 hours. After cooling to room temperature, the mixture was filtered, sonicated for 20-30 minutes, and dried at 80-90°C to obtain reinforced fibers.

[0015] Furthermore, the ratio of fiber, 80wt% aqueous ethanol solution, and silane coupling agent KH550 is 12~15g: 600~700mL: 6~8g.

[0016] Furthermore, the ratio of zinc acetate dihydrate, sodium hydroxide, ethanol and modified fiber is 0.22~0.33g: 0.08~0.12g: 800~1000mL: 12~15g.

[0017] Furthermore, the ratio of zinc chloride, hexamethylenetetramine, silver nitrate, distilled water, and fiber precursor is 1.36~1.66g: 2.8~3.2g: 0.08~0.12g: 400~500mL: 12~15g.

[0018] Furthermore, the fibers include, but are not limited to, glass fibers, basalt fibers, and carbon fibers.

[0019] Furthermore, the specific preparation steps of the coal gangue-based ceramic brick adhesive used for thin-layer paving are as follows: Composite coal gangue powder and ordinary silicate cement are added to a mixer and dry-mixed for 6-10 minutes. Then copolymer powder, hydroxypropyl methylcellulose, starch ether, sodium formate, reinforcing fiber and early strength agent are added and stirred for another 8-10 minutes. Water is then added and stirred at 220-250 rpm for 10-15 minutes to obtain a coal gangue-based ceramic brick adhesive for thin-layer paving.

[0020] The beneficial effects of this invention are: 1. This invention, through multi-level material design and functional modification, firstly involves high-temperature decarburization activation and pore structure design of coal gangue aggregate, making it a multifunctional composite carrier for loading phase change microcapsules and ultrafine sodium-based montmorillonite. The phase change microcapsules of the n-alkane core material release latent heat during the initial setting of the adhesive, compensating for its early strength performance and reducing its frost heave stress, thus inhibiting crack propagation. Then, the surface is modified with a silane coupling agent to improve the durability of outdoor thin-layer ceramic tiles.

[0021] 2. The composite coal gangue powder in this invention, after high-temperature decarburization and activation to increase its specific surface area, successfully adsorbs n-octadecane / silica core-shell phase change microcapsules into its pore structure. Through phase change behavior, it effectively buffers temperature stress and significantly enhances the freeze-thaw resistance of the adhesive. Ultrafine sodium-based montmorillonite fills the gaps between particles, optimizing interfacial compatibility while significantly reducing porosity, improving density and mechanical strength. Furthermore, its low hardness and high flexibility provide lubrication and buffering, reducing the breakage of phase change microcapsules during mixing and ensuring structural integrity. Finally, hydrophobic long chains are grafted onto the surface of the silane coupling agent KH570 to form a durable hydrophobic layer that effectively inhibits water penetration.

[0022] 3. The reinforcing fiber in this invention involves the in-situ hydrothermal growth of tetrane-shaped zinc oxide crystals on the surface of basalt fibers modified with silane coupling agent KH550. This unique three-dimensional structure, on the one hand, deeply embeds itself into the cement matrix through the "mechanical anchoring" effect of its sharp ends, enhancing the interfacial bonding force between the fiber and the matrix, thereby strengthening the tensile strength, crack resistance, and anti-slip properties of the material. On the other hand, the tetrane-shaped zinc oxide, with its huge specific surface area and highly efficient catalytic activity, endows the material with broad-spectrum and long-lasting antibacterial and antifungal capabilities through the synergistic effect of physical puncture and chemical sterilization. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments in 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: A method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving, comprising the following steps: S1: Add 50g of n-octadecane and 750mL of formamide to a three-necked flask, stir at 350rpm and 55℃ for 30min, then add 10g of hexadecyltrimethylammonium bromide, stir for 5h, then add 50g of tetraethyl silicate, stir for 4h, then add 750mL of 2wt% hydrochloric acid dropwise at 800μL / min, stir for 5h after the addition is complete, keep warm for 24h, filter, wash and dry to obtain phase change microcapsules.

[0025] Phase change microcapsules were formed by hydrolysis-condensation reaction using n-octadecane as the core material and tetraethyl silicate as the shell material via the sol-gel method.

[0026] S2: Add 500g of coal gangue powder that has passed through a 100-mesh sieve to a ball mill and ball mill at 500 rpm for 3 hours. Transfer the powder to a muffle furnace and calcine at 800℃ for 4 hours at 5℃ / min to obtain decarburized coal gangue powder. Mix 50g of phase change microcapsules and 10g of ultrafine sodium-based montmorillonite evenly, then add the mixture to 500g of decarburized coal gangue powder and stir at 350 rpm for 10 minutes. Transfer the mixture to 10L of 5wt% silane coupling agent KH570 solution and soak at 70℃ for 5 hours. Filter the mixture and dry it to constant weight to obtain composite coal gangue powder.

[0027] After increasing the specific surface area and reactivity of decarbonized coal gangue, phase change microcapsules are physically adsorbed into the pores of the coal gangue, enhancing the mechanical strength and durability of the composite material and reducing the porosity to reduce water absorption. Then, after modification with a silane coupling agent, the waterproof performance is optimized, effectively inhibiting water penetration.

[0028] S3: Add 12g of basalt fiber to 600mL of 80wt% ethanol aqueous solution, then add 6g of silane coupling agent KH550, stir at 80℃ for 3h, filter, wash the product with deionized water and ethanol 3 times, freeze dry to obtain modified basalt fiber. Add 0.22g of zinc acetate dihydrate and 0.08g of sodium hydroxide to 800mL of ethanol, stir at 25℃ for 30min, sonicate at 60℃ for 35min, then add 12g of modified basalt fiber, soak for 30min, filter, heat at 150℃ for 10min, repeat soaking and heating 5 times to obtain fiber precursor. Add 1.36g zinc chloride, 2.8g hexamethylenetetramine and 0.08g silver nitrate to 400mL distilled water and stir for 5min. Then add 12g fiber precursor, seal the container, heat to 130℃ at a rate of 5℃ / min, keep warm for 6h, cool to room temperature, filter, sonicate for 20min, and dry at 80℃ to obtain reinforced fiber.

[0029] Basalt fibers were aminated using silane coupling agent KH550, and zinc oxide whiskers generated by the reaction of zinc acetate dihydrate and sodium hydroxide were loaded onto the modified fiber surface. Then, through hydrothermal self-assembly, zinc chloride provided the zinc source, and under the control of silver nitrate, the whiskers grew in a directional manner along the fiber surface to form a tetrap-like structure. The three-dimensional structure of tetraneedle zinc oxide and basalt fiber can efficiently disperse external forces, improve mechanical properties, and enhance the tensile, crack, and slip resistance between the fiber and the cement matrix. At the same time, nano zinc oxide gives the product antibacterial and antifungal functions.

[0030] S4: Add 450 parts of composite coal gangue powder and 250 parts of ordinary silicate cement to a mixer and dry mix for 6 minutes. Then add 15 parts of copolymer adhesive powder, 1 part of hydroxypropyl methylcellulose, 0.2 parts of starch ether, 5 parts of sodium formate, 8 parts of reinforcing fiber and 10 parts of early strength agent, and continue mixing for 8 minutes. Then add 180 parts of water and mix at 220 rpm for 10 minutes to obtain a coal gangue-based ceramic brick adhesive for thin-layer paving.

[0031] Example 2: This example provides a method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving. The difference from Example 1 is that n-heptadecane or n-nonadecane is used instead of n-octadecane in step S1 to prepare the coal gangue-based ceramic brick adhesive for thin-layer paving.

[0032] Example 3: This example provides a method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving. The difference from Example 1 is that glass fiber is used instead of basalt fiber in step S3 to prepare the coal gangue-based ceramic brick adhesive for thin-layer paving.

[0033] Example 4: This example provides a method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving. The difference from Example 1 is that in step S3, the ratio of basalt fiber, 80wt% ethanol aqueous solution, and silane coupling agent KH550 is 15g:700mL:8g; the ratio of zinc acetate dihydrate, sodium hydroxide, ethanol, and modified basalt fiber is 0.33g:0.12g:1000mL:15g; and the ratio of zinc chloride, hexamethylenetetramine, silver nitrate, distilled water, and fiber precursor is 1.66g:3.2g:0.12g:500mL:15g.

[0034] Example 5: This example provides a method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving. The difference from Example 1 is that in step S4, the mass ratio of composite coal gangue powder, ordinary silicate cement, copolymer powder, hydroxypropyl methylcellulose, starch ether, sodium formate, reinforcing fiber, early strength agent and water is 550:300:20:2:0.5:8:10:15:200, thus preparing a coal gangue-based ceramic brick adhesive for thin-layer paving.

[0035] The raw materials used in Examples 1 to 5 of this application are all commercially available. The copolymer powder is any one of ethylene-vinyl acetate copolymer powder, vinyl acetate-ethylene copolymer powder, and styrene-butadiene copolymer powder. The early strength agent is any one of triethanolamine, calcium formate, and sodium sulfate. The basalt fiber has a length of 1-3 mm and a diameter of 10-15 μm. The phase change microcapsules have a size of 1-5 μm.

[0036] Comparative Example 1: The difference from Example 1 is that step S1 is omitted, phase change microcapsules are not added in step S2, and the remaining steps remain unchanged, thus preparing a coal gangue-based ceramic brick adhesive for thin-layer paving.

[0037] Comparative Example 2: The difference from Example 1 is that ultrafine sodium-based montmorillonite is not added in step S2, while the other steps remain unchanged, to prepare a coal gangue-based ceramic brick adhesive for thin-layer paving.

[0038] Comparative Example 3: The difference from Example 1 is that the reinforcing fiber in step S4 is replaced with the modified basalt fiber in step S3, while the other steps remain unchanged, to prepare a coal gangue-based ceramic brick adhesive for thin-layer paving.

[0039] The ceramic tile adhesives prepared in Examples 1-3 and Comparative Examples 1-3 were tested according to the standard "Ceramic Tile Adhesives (JC / T 547-2017)" for bonding strength (after 28 days of curing), bonding strength after freeze-thaw cycles (-15℃ freezing for 4 hours → 20℃ water thawing for 4 hours, 25 cycles), and slippage of ceramic tiles after 20 minutes of bonding. Antibacterial tests were conducted using the inhibition zone method, with Staphylococcus aureus and Escherichia coli as test bacteria. The bacteria were cultured and diluted to 106 CFU / mL, and then the bacterial solution was spread on agar plates and incubated in a 37℃ incubator for 12 hours. The adhesives prepared in Examples 1-5 were made into samples with a diameter of 5 mm and a thickness of 1 mm. The samples were immersed in 10 wt% ethanol solution for 24 hours, dried, and then placed on agar plates and incubated in an incubator for 12 hours. The diameter of the inhibition zone was then measured.

[0040] The results are shown in Table 1: Table 1 Performance Test Results of Coal Gangue-Based Ceramic Brick Adhesive

[0041] As shown in Table 1, the coal gangue-based ceramic brick adhesives prepared in Examples 1 to 5 are significantly superior to those in Comparative Examples 1 to 3. The phase change microcapsules buffer thermal stress through phase change, thereby improving the low-temperature durability of the adhesive. The ultrafine sodium-based montmorillonite acts as a filler to improve anti-slip properties and also plays a lubricating and buffering role, reducing the rupture of the phase change microcapsules. The tetraneedle-shaped zinc oxide reinforced fibers provide antibacterial function. The complementary and synergistic enhancement of the functions among the three achieves comprehensive optimization of durability, mechanical strength, and functionality.

[0042] The bond strength of the sample in Comparative Example 1 decreased significantly after freeze-thaw cycles, possibly due to the lack of phase change microcapsules. Moisture could penetrate the porous structure of the coal gangue and freeze, generating huge frost heave stress that would damage the aggregate particles and their interface with the cement matrix from the inside. Adding phase change microcapsules to the pores of the coal gangue can release latent heat during low-temperature processes. This heat, combined with the heat of crystallization of water, effectively slows down the rate of temperature decrease and ice crystal formation in the pores, thereby significantly suppressing frost heave stress and protecting the integrity of the aggregate.

[0043] The significant increase in tensile bond strength and slip distance in Comparative Example 2 may be due to the lack of ultrafine sodium-based montmorillonite. Bentonite micro-nano sheets preferentially adsorb onto the surface of microcapsules through electrostatic interaction, forming a rough hydrophilic mineral transition layer, which then fills the pores between coal gangue particles, significantly improving the compactness and mechanical strength of the solidified matrix. The absence of this component directly causes a loose microstructure, resulting in insufficient tensile strength and loss of macroscopic anti-slip properties, leading to an increase in slip. The decrease in bond strength after freeze-thaw may be due to the lack of its lubricating and buffering effect, causing the phase change microcapsules to break under stress during mixing, thus reducing its related effects.

[0044] The diameter of the inhibition ring in Comparative Example 3 was significantly reduced, possibly because tetraneedle zinc oxide was not loaded onto the surface of the ordinary basalt fiber modified with silane coupling agent, thus losing its antibacterial function. The unique three-dimensional structure of tetraneedle zinc oxide can increase its specific surface area, improve the antibacterial effect, and increase the roughness of the fiber components, reduce slippage, and improve the bonding strength.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A coal gangue-based ceramic brick adhesive for thin-layer paving, characterized in that, By weight, the raw materials include the following components: The mixture consists of 450-550 parts of composite coal gangue powder, 250-300 parts of ordinary silicate cement, 15-20 parts of copolymer adhesive powder, 1-2 parts of hydroxypropyl methylcellulose, 0.2-0.5 parts of starch ether, 5-8 parts of sodium formate, 8-10 parts of reinforcing fiber, 10-15 parts of early strength agent, and 180-200 parts of water. The composite coal gangue powder is prepared through the following steps: Using ultrafine sodium-based montmorillonite as a buffer phase, phase change microcapsules containing n-alkane core material were combined with decarburized coal gangue powder, and then modified with silane coupling agent KH570 to obtain composite coal gangue powder. The n-alkane is any one of n-heptadecane, n-octadecane, and n-nonadecanane.

2. The method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving according to claim 1, characterized in that, The specific preparation steps of the phase change microcapsules are as follows: n-Alkanes and formamide were added to a three-necked flask and stirred at 350-450 rpm and 55-65°C for 30-40 min. Then hexadecyltrimethylammonium bromide was added and stirred for 5-6 h. Tetraethyl silicate was added and stirred for 4-5 h. 2 wt% hydrochloric acid was added dropwise at 800 μL / min. After the addition was complete, the mixture was stirred for 5-6 h and kept at this temperature for 24-36 h. The mixture was then filtered, washed, and dried to obtain phase change microcapsules.

3. The method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving according to claim 2, characterized in that, The ratio of n-alkane, formamide, hexadecyltrimethylammonium bromide, tetraethyl silicate and 2wt% hydrochloric acid is 50-60g: 750-900mL: 10-12g: 50-60g: 750-900mL.

4. The method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving according to claim 1, characterized in that, The specific preparation steps of the composite coal gangue powder are as follows: Phase change microcapsules and ultrafine sodium-based montmorillonite were mixed evenly and then added to decarburized coal gangue powder. The mixture was stirred at 350-450 rpm for 10-20 min, transferred to a 5 wt% solution of silane coupling agent KH570, soaked at 70-80℃ for 5-6 h, filtered, and dried to constant weight to obtain composite coal gangue powder.

5. The method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving according to claim 4, characterized in that, The ratio of the phase change microcapsules, ultrafine sodium-based montmorillonite, decarburized coal gangue powder, and 5 wt% silane coupling agent KH570 solution is 50~60g:10~15g:500~600g:10~12L.

6. The method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving according to claim 1, characterized in that, The specific preparation steps of the reinforced fiber are as follows: Zinc chloride, hexamethylenetetramine, and silver nitrate were added to distilled water and stirred for 5-10 minutes. Then, fiber precursors were added, the container was sealed, and the mixture was heated to 130-150°C at a rate of 5°C / min and kept at that temperature for 6-8 hours. After cooling to room temperature, the mixture was filtered, sonicated for 20-30 minutes, and dried at 80-90°C to obtain reinforced fibers. The ratio of zinc chloride, hexamethylenetetramine, silver nitrate, distilled water, and fiber precursor is 1.36~1.66g: 2.8~3.2g: 0.08~0.12g: 400~500mL: 12~15g.

7. A method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving according to claim 6, characterized in that, The fiber precursor is prepared by the following steps: Zinc acetate dihydrate and sodium hydroxide were added to ethanol and stirred at 25-35°C for 30-40 min. The mixture was then sonicated at 60-70°C for 35-45 min. Modified fibers were then added and soaked for 30-40 min. The mixture was filtered and heated at 150-160°C for 10-20 min. The soaking and heating process was repeated 5-8 times to obtain the fiber precursor.

8. A method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving according to claim 7, characterized in that, The ratio of zinc acetate dihydrate, sodium hydroxide, ethanol and modified fiber is 0.22~0.33g: 0.08~0.12g: 800~1000mL: 12~15g.

9. A method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving according to claim 8, characterized in that, The modified fiber is glass fiber or basalt fiber modified with silane coupling agent KH550.

10. A method for preparing a coal gangue-based ceramic brick adhesive for thin-layer paving according to claim 1, characterized in that, Includes the following steps: Composite coal gangue powder and ordinary silicate cement are added to a mixer and dry-mixed for 6-10 minutes. Then copolymer powder, hydroxypropyl methylcellulose, starch ether, sodium formate, reinforcing fiber and early strength agent are added and stirred for another 8-10 minutes. Water is then added and stirred at 220-250 rpm for 10-15 minutes to obtain a coal gangue-based ceramic brick adhesive for thin-layer paving.

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