Method for preparing adhesive stone permeable pavement from solid waste-based material

Abstract

The invention discloses a method for preparing an adhesive stone permeable pavement from a solid waste-based material, and relates to the technical field of building materials and road engineering, and the method comprises the following steps: drying 0.075-2.36 mm solid waste filler, and spraying an ethyl silicate ethanol solution to generate a 80-150 nm hydrophobic silicon dioxide shell layer in situ; according to the method, the solid waste mixing amount reaches 18%, the water permeability coefficient is 0.28 mm / s, the performance is stable after dry-wet and freeze-thaw cycles, high-performance utilization of the high-mixing-amount solid waste is achieved, and the method is suitable for industrial production. The problems of poor interfacial compatibility between industrial solid waste micro powder and an organic adhesive, insufficient early strength of a mixture, reduced water permeability, degraded durability and limited solid waste mixing amount at present are solved.

Description

Technical Field

[0001] This invention relates to the field of building materials and road engineering technology, specifically to a method for preparing adhesive-bonded permeable pavement using solid waste-based materials. Background Technology

[0002] The high-value utilization of bulk industrial solid waste such as construction waste, fly ash, and steel slag has become a key breakthrough in green building materials and sustainable infrastructure construction. As a new type of paving material combining ecological functions and engineering performance, adhesive-bonded permeable pavement has been widely used in light-load traffic scenarios such as urban sidewalks, plazas, park trails, and eco-friendly parking lots due to its high interconnected porosity of 15% to 25%, excellent rainwater infiltration capacity, and good landscape coordination. This type of pavement typically consists of a skeleton structure made of coarse aggregate with a particle size of 5mm to 10mm, supplemented with natural sand or mineral powder as filler, and coated with organic adhesives such as polyurethane and epoxy resin to form a continuous bonding network, providing necessary mechanical load-bearing capacity while maintaining high permeability. In this system, although the filler does not directly bear the load, it has a decisive influence on the uniformity of adhesive distribution, the density of the interface transition zone, and the overall structural stability.

[0003] In recent years, the introduction of industrial solid waste powder as a substitute for traditional mineral fillers into adhesive stone systems has been regarded as a synergistic path to achieve large-scale solid waste disposal and green transformation of building materials. However, solid waste powders such as fly ash and steel slag contain a large amount of active silica-alumina components due to the high-temperature smelting or combustion process, and their surfaces are generally enriched with hydrophilic hydroxyl groups (-OH), resulting in significantly high surface energy. Meanwhile, mainstream organic adhesives such as polyurethane prepolymers have typical hydrophobic properties. The two exhibit significant interfacial energy mismatch thermodynamically, making it difficult to achieve effective wetting and molecular-level contact, thus hindering physical adsorption and even the formation of potential chemical bonds. This inherent interfacial compatibility defect not only weakens the coating efficiency of adhesives on solid waste particles but also induces interfacial micropores and stress concentration at the microscale, becoming the root cause of macroscopic mechanical property degradation and durability decline. To overcome this obstacle, existing technologies mostly employ mechanical activation, acid-base etching, or surface modification with coupling agents for solid waste pretreatment. For example, some studies have modified fly ash with silane coupling agents, which can reduce surface polarity to some extent, but the resulting organic monolayers are often loosely structured and have limited thickness, making it difficult to construct a stable and continuous interfacial transition zone. Another approach attempts to introduce nano-silica to enhance interfacial interactions, but the high specific surface area and strong van der Waals forces of the nanoparticles lead to severe agglomeration, making it impossible to achieve uniform coating of solid waste particles. Instead, it exacerbates the heterogeneity inside the mixture.

[0004] A deeper problem lies in the fact that while the aforementioned modification strategies attempt to improve interfacial bonding, they often inadvertently sacrifice the core functional attribute of the cemented aggregate system—permeability. When the amount of adhesive is increased to compensate for weak interfacial bonding, excessive colloid can easily flow through the aggregate gaps and block interconnected pores, causing the permeability coefficient to plummet to below 0.1 mm / s, far below the benchmark value of 0.15 mm / s recommended in the "Technical Specification for Permeable Pavement." On the other hand, if the amount of adhesive is strictly controlled to preserve the pore structure, insufficient interfacial bonding strength leads to low early strength, resulting in aggregate loosening and surface spalling during the paving or initial service stages. Furthermore, solid waste particles that have not undergone effective interfacial reinforcement are highly susceptible to becoming channels for moisture intrusion and microcrack propagation under environmental stresses such as wet-dry cycles, freeze-thaw cycles, or ultraviolet aging, accelerating the degradation of material properties. Therefore, although industrial solid waste is theoretically physically feasible as a filler, its actual dosage has long been suppressed to below 10% due to bottlenecks in interface control technology. This fails to meet the environmental protection requirements of large-scale solid waste disposal and also cannot support the engineering application standards of high-performance permeable pavements. Fundamentally, existing technological approaches have failed to establish an effective synergistic mechanism among high solid waste dosage, strong interfacial bonding, and high permeability retention, instead resulting in a performance trade-off dilemma where one aspect gains at the expense of the other.

[0005] Therefore, how to construct a gradient interface layer with hydrophobicity, chemical stability and mechanical strength on the surface of solid waste powder in situ through a simple, environmentally friendly and industrially feasible technical means, so as to simultaneously increase the solid waste content to more than 15%, maintain the water permeability coefficient at more than 0.2 mm / s, and significantly enhance the durability of long-term service under harsh environmental conditions, has become a key challenge and a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] Based on this, and in response to the above problems, this invention proposes a method for preparing adhesive-bonded permeable pavement using solid waste-based materials. This method solves the problems of poor interfacial compatibility between industrial solid waste powder and organic adhesives, insufficient early strength of the mixture, decreased permeability, deterioration of durability, and limited solid waste content.

[0007] The technical solution of this invention is: A method for preparing adhesive-bonded stone permeable pavement using solid waste-based materials includes the following steps: Step 1: Dry solid waste fillers with a particle size of 0.075 mm to 2.36 mm at 105°C for 4 hours; Step 2: Put the dried solid waste filler into a high-speed mixer and pre-stir at 800 r / min for 3 minutes. Then spray in a 12% ethyl silicate ethanol solution, the amount of which is 6% of the mass of the solid waste filler. Under stirring conditions, carry out a sol-gel reaction for 25 minutes to generate an amorphous silica hydrophobic modified shell layer in situ on the surface of the solid waste particles. Step 3: Mix the surface-modified solid waste filler with basalt or diabase coarse aggregate with a particle size of 5mm to 10mm at a mass ratio of 1:4, and mix for 90 seconds in a forced twin-shaft mixer. Step 4: Mix the polyurethane prepolymer and curing agent at a mass ratio of 3:1 to form an organic adhesive. Spray the adhesive evenly onto the mixture at a ratio of 5% of the total mass of the mixture and continue stirring at room temperature for 120 seconds. Step 5: Press the well-mixed material into a static mold at a pressure of 12MPa for 180 seconds. After demolding, cure for 7 days at 20℃ and relative humidity greater than 95% to obtain the adhesive stone permeable pavement panel.

[0008] Preferably, the ethyl silicate ethanol solution is sprayed through an atomizing nozzle, and the atomized droplet size is 50 μm to 100 μm.

[0009] Preferably, the humidity in the stirring chamber is controlled between 40% and 60% during the sol-gel reaction, and the product is heat-treated at 400°C for 2 hours after the reaction is completed.

[0010] Preferably, the thickness of the amorphous silica hydrophobic modified shell is 80 nm to 150 nm, and the surface contact angle is 112°.

[0011] Preferably, the polyurethane prepolymer is isocyanate-terminated, with a functionality of 2.3 and a number-average molecular weight of 2000; the curing agent is a polyol with a hydroxyl value of 220 mg KOH / g.

[0012] Preferably, the organic adhesive is sprayed through a multi-channel spiral nozzle system, with the spray flow rate accuracy controlled within ±2%, and the spray angle covering the entire cross-section of the stirring area.

[0013] Preferably, the coarse aggregate is dried at 110°C to a moisture content of less than 0.3% before mixing.

[0014] Preferably, the inner wall of the mold used for hydrostatic molding is coated with a release agent formed by a composite emulsion of fluorosilane compound and mineral oil, with a coating thickness of 10 μm to 15 μm.

[0015] Preferably, the surface of the product after curing is subjected to plasma treatment with a power of 300W and a treatment time of 60 seconds.

[0016] Preferably, the solid waste filler accounts for 18% of the total mass of the mixture, and the permeability coefficient of the resulting permeable pavement panel is 0.28 mm / s.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention constructs an in-situ amorphous silica hydrophobic modified shell on the surface of solid waste filler, adjusting its surface energy properties and improving the interfacial compatibility between hydrophilic solid waste particles and hydrophobic organic adhesives. This achieves a synergistic effect of physical anchoring and potential chemical bonding between the two phases, thereby significantly improving the interfacial bonding strength of the composite material. Due to the optimized interfacial bonding state, the amount of adhesive can be precisely controlled within a reasonable range, ensuring sufficient bonding performance while avoiding excessive colloid clogging of the pore structure. This allows the final product to maintain a permeability coefficient of 0.28 mm / s even with a solid waste content as high as 18%. This solves the current problems of poor interfacial compatibility between industrial solid waste powder and organic adhesives, insufficient early strength of the mixture, decreased permeability, deterioration of durability, and limited solid waste content. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic flowchart illustrating the steps of a method for preparing adhesive-bonded permeable pavement using solid waste-based materials, as described in an embodiment of the present invention. Figure 2 This is a schematic diagram of the process flow for a method of preparing adhesive-bonded permeable pavement using solid waste-based materials, as described in an embodiment of the present invention. Detailed Implementation

[0020] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0021] In the description of the embodiments of the present invention, it should be understood that the terms "length", "vertical", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0024] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] The following disclosure provides many different implementations or examples for carrying out different structures of the embodiments of the present invention. To simplify the disclosure of the embodiments of the present invention, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. Furthermore, reference numerals and / or reference letters may be repeated in different examples of the embodiments of the present invention; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0026] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0027] Example: like Figures 1 to 2 As shown in the figure, this embodiment discloses a method for preparing adhesive-bonded stone permeable pavement using solid waste-based materials, including the following steps: Step 1: Crush and screen construction waste, fly ash or steel slag, control the particle size to be in the range of 0.075mm to 2.36mm as solid waste filler, and place it in a drying equipment to dry at 105℃ for 4 hours to remove surface adsorbed water; Step 2: Put the dried solid waste filler into a high-speed mixer and pre-stir at 800 rpm for 3 minutes to make the particles evenly dispersed. Then, spray a 12% ethyl silicate ethanol solution into the mixing chamber at a rate of 6% of the mass of the solid waste filler. Continue stirring at the same time to generate an amorphous silica layer on the surface of the solid waste particles in situ using a sol-gel reaction, forming a hydrophobic modified shell with a gradient transition structure. The reaction time is controlled at 25 minutes. Step 3: Mix the surface-modified solid waste filler with coarse aggregate at a mass ratio of 1:4. The coarse aggregate has a particle size of 5mm to 10mm and is made of basalt or diabase. The mixing process is completed in a forced twin-shaft mixer for 90 seconds to ensure that the filler is evenly distributed in the gaps between the aggregates. Step 4: Mix the polyurethane prepolymer and curing agent at a mass ratio of 3:1 to form an organic adhesive system. Spray the adhesive evenly onto the mixture obtained in Step 3 at a ratio of 5% of the total mass of the mixture. Continue stirring at room temperature for 120 seconds to allow the adhesive to fully coat the surface of the aggregate and modified filler, forming a continuous adhesive film. Step 5: Spread the well-mixed material into the mold, and use the static pressure molding process. The pressure is set to 12MPa and the holding time is 180 seconds. After molding, demold and place in a standard curing room. The temperature is controlled at 20℃ and the relative humidity is greater than 95%. After curing for 7 days, the finished adhesive stone permeable pavement panel is obtained.

[0028] In step 2, the ethyl silicate ethanol solution is sprayed in through an atomizing nozzle. The spray particle size is controlled between 50μm and 100μm to ensure that the droplets are evenly covered on the surface of the rotating solid waste particles under the action of high-speed airflow, avoiding local over-wetting or agglomeration.

[0029] In step 2, during the sol-gel reaction, the humidity in the stirring chamber is controlled within the range of 40% to 60%. After the reaction is completed, the product is heat-treated at 400°C for 2 hours to promote the densification of the amorphous silica network structure and improve the mechanical strength and chemical stability of the shell.

[0030] In step 2, the 12% ethyl silicate ethanol solution is a mixture of 12% ethyl silicate ethanol solution and a hydrophobic silane coupling agent. The injection volume of the mixed solution is 6% of the mass of the solid waste packing material. For the selection of hydrophobic silane, alkyl silanes are preferred, such as methyltrimethoxysilane (MTMS) or octyltriethoxysilane (OTES), whose hydrolysis rate is slightly faster than that of ethyl silicate, and which have hydrophobic groups (-CH3, -C8H). 17 It has low steric hindrance and is easily enriched on the surface. The mixing ratio of ethyl silicate to hydrophobic silane is 7:3-8:2, which can be adjusted according to hydrophobic requirements.

[0031] Gradient formation mechanism: Hydrolysis stage: Hydrophobic silanes hydrolyze faster, preferentially generating silanols containing hydrophobic groups; TEOS hydrolyzes more slowly, generating hydrophilic silanols.

[0032] Condensation stage: Inner layer: Hydrophilic silanol preferentially condenses with the active groups on the surface of solid waste particles to form a hydrophilic silica bottom layer; Intermediate layer: Unreacted hydrophilic silanols and hydrophobic silanols co-condense, with the proportion of hydrophobic groups gradually increasing; Outer layer: The remaining hydrophobic silanol preferentially condenses on the shell surface, and the hydrophobic groups are densely enriched to form a hydrophobic surface layer; Ultimately, a hydrophobically modified shell with a gradient transition structure is formed.

[0033] The hydrophobic modified shell generated in step 2 has a thickness of 80nm to 150nm, and its surface contact angle is increased from 35° of the original solid waste to 112°, which significantly reduces the surface energy and enhances the wetting and spreading ability with polyurethane adhesive.

[0034] In step 4, the polyurethane prepolymer is isocyanate-terminated with a functionality of 2.3 and a number-average molecular weight of 2000. The curing agent is a polyol with a hydroxyl value of 220 mg KOH / g. The activity period of the two mixtures is greater than 45 minutes, which meets the requirements of on-site construction operations.

[0035] In step 4, the adhesive is sprayed using a multi-channel spiral nozzle system, with the spray flow rate accuracy controlled within ±2%, and the spray angle covering the entire cross-section of the mixing area to ensure no dead corners are covered.

[0036] In step 5, the inner wall of the mold used for hydrostatic molding is coated with a release agent, which is a composite emulsion of fluorosilane compounds and mineral oil. The coating thickness is 10μm to 15μm, which effectively reduces the molding friction resistance.

[0037] The product cured for 7 days in step 5 was further subjected to a dry-wet cycle test simulation. After 15 cycles, the compressive strength retention rate was greater than 92%, and after 50 freeze-thaw cycles, the mass loss rate was less than 1.2%, indicating that it has excellent environmental durability.

[0038] Before step 4, the coarse aggregate is pre-dried by drying it in an oven at 110°C until the moisture content is less than 0.3% to prevent moisture from interfering with the crosslinking reaction of the adhesive.

[0039] After molding in step 5, the surface of the product is subjected to plasma treatment with a power of 300W and a treatment time of 60 seconds to introduce polar groups to enhance the hydrophilicity of the surface and maintain the long-term stability of the water permeability.

[0040] In the method described, the amount of solid waste filler is 18% of the total mass of the mixture, which is more than 80% higher than that of traditional technology. The measured permeability coefficient reaches 0.28 mm / s, which is 1.8 times higher than the industry standard limit, achieving synergistic optimization of high content and high performance.

[0041] In step 1, the crushing and screening process adopts a three-stage jaw crushing combined with vibrating screening. The screen apertures are 40mm, 10mm and 0.075mm respectively, to ensure that the particle size distribution meets the gradation requirements, and the proportion of particles in the range of 0.075mm to 2.36mm is not less than 90%.

[0042] In step 3, the linear velocity of the mixing blades of the forced twin-shaft mixer is 2.5 m / s, the distance between adjacent blades is 150 mm, and the material tumbling frequency during the mixing process is greater than 12 times per minute, ensuring that the coefficient of variation of the mixing uniformity is less than 5%.

[0043] After the standard curing in step 5 is completed, infrared spectroscopy is performed on the product. The results show that a significant carbonyl absorption peak appears at 1730 wavenumber, confirming that the polyurethane main chain structure is intact. A strong Si-O-Si stretching vibration peak is observed at 1080 wavenumber, indicating that the modified shell layer has been successfully constructed and has potential interfacial interaction with the adhesive.

[0044] The method described in this invention is applicable to scenarios such as urban slow traffic systems, garden landscape roads, and ecological parking lots, with a single-day single-line production capacity of up to 800m², meeting the needs of large-scale engineering applications.

[0045] This invention constructs an in-situ amorphous silica hydrophobic modified shell on the surface of solid waste filler, adjusting its surface energy properties and improving the interfacial compatibility between hydrophilic solid waste particles and hydrophobic organic adhesives. This achieves a synergistic effect of physical anchoring and potential chemical bonding between the two phases, thereby significantly improving the interfacial bonding strength of the composite material. Due to the optimized interfacial bonding state, the amount of adhesive can be precisely controlled within a reasonable range, ensuring sufficient bonding performance while avoiding excessive colloid clogging of the pore structure. This allows the final product to maintain a water permeability coefficient of 0.28 mm / s even with a solid waste content as high as 18%. The dense silica shell prevents moisture intrusion and effectively inhibits the initiation and propagation of interfacial microcracks under alternating wet and dry conditions and freeze-thaw cycles. After 15 wet and dry cycles, the product retains more than 92% of its strength, and after 50 freeze-thaw cycles, the mass loss rate is less than 1.2%. By optimizing the raw material gradation, mixing process, and molding parameters, the high uniformity and structural stability of the mixture are ensured. Coarse aggregate is firmly encapsulated by a continuous cementitious film, preventing loosening and detachment, thus improving the integrity of the road surface. This invention achieves high-value, large-scale utilization of bulk industrial solid waste in road engineering, breaking through the bottleneck of traditional technologies where solid waste content cannot exceed 10%. It promotes technological progress in green and low-carbon building materials and solves the current problems of poor interfacial compatibility between industrial solid waste powder and organic adhesives, insufficient early strength of the mixture, decreased permeability, deteriorated durability, and limited solid waste content.

[0046] More specifically: First, construction waste, fly ash, or steel slag are selected as raw materials and fed into a three-stage jaw crusher system for primary, intermediate, and fine crushing. The crushed material is then graded by a vibrating screen with mesh sizes set to 40mm, 10mm, and 0.075mm to ensure the final particle size is strictly controlled within the range of 0.075mm to 2.36mm. Particles within this size range account for no less than 90%, meeting the basic requirements for subsequent mixture gradation design. The resulting solid waste filler is then transferred to a drying device and dried at a constant temperature of 105℃ for 4 hours to completely remove adsorbed moisture from the particle surface, reducing the moisture content to below 0.1% to prevent residual moisture from interfering with subsequent chemical reactions and adhesive processes.

[0047] After drying, the solid waste filler was placed in a high-speed mixer, and the mixer was started and operated at 800 rpm for 3 minutes to promote full dispersion of the particles and form a dynamic suspension. Then, a 12% ethyl silicate ethanol solution was uniformly sprayed into the mixing chamber through an atomizing nozzle, with the spray volume precisely controlled to 6% of the solid waste filler mass. The droplet size generated by the atomizing nozzle was maintained between 50 μm and 100 μm. Under the action of the high-speed rotating airflow, the droplets could uniformly cover the surface of the moving solid waste particles, effectively preventing local over-wetting or agglomeration. Simultaneously, the humidity inside the mixing chamber was controlled within the range of 40% to 60% to ensure the stable progress of the sol-gel reaction. Under continuous stirring, ethyl silicate underwent hydrolysis and condensation reactions on the particle surface, forming an amorphous silica shell in situ. The shell exhibits a gradient transition structure with a thickness ranging from 80 nm to 150 nm. Its surface contact angle significantly increases from 35° in the original solid waste to 112°, indicating a substantial reduction in surface energy and enhanced hydrophobicity. After the reaction, the product is placed in a muffle furnace and heat-treated at 400°C for 2 hours to further densify the amorphous silica network structure, thereby improving the mechanical strength and chemical stability of the shell.

[0048] The surface-modified solid waste filler was then mixed with coarse aggregate at a mass ratio of 1:4. The coarse aggregate used was basalt or diabase, with a particle size ranging from 5mm to 10mm, and was dried in an oven at 110℃ until the moisture content was below 0.3% before mixing to eliminate the adverse effects of moisture on the subsequent crosslinking reaction of the adhesive. The mixing operation was carried out in a forced twin-shaft mixer equipped with mixing blades of specific geometric parameters, a linear velocity set at 2.5m / s, and a spacing of 150mm between adjacent blades. During the mixing process, the material tumbled more than 12 times per minute to ensure that the filler was evenly distributed in the gaps between the coarse aggregates, and the coefficient of variation of the mixing uniformity was controlled within 5%.

[0049] After the dry mixing of aggregates and modified fillers is completed, the adhesive addition stage begins. The organic adhesive system used consists of polyurethane prepolymer and curing agent in a 3:1 mass ratio. The polyurethane prepolymer is isocyanate-terminated with a functionality of 2.3 and a number-average molecular weight of 2000; the curing agent is a polyol with a hydroxyl value of 220 mgKOH / g. The activity period of the mixture is greater than 45 minutes, meeting the operational window requirements for on-site construction. The adhesive, at a ratio of 5% of the total mass of the mixture, is uniformly sprayed into the mixture using a multi-channel spiral spray system. The spray flow rate accuracy of this system is controlled within ±2%, and the spray angle covers the entire cross-section of the mixing area, ensuring that every aggregate and filler particle is completely coated with the adhesive, forming a continuous and uniform adhesive film. After spraying, stirring continues for 120 seconds at room temperature to allow the adhesive to fully wet the particle surface and initially complete the physical coating.

[0050] The uniformly mixed material is then conveyed into the molding die. The inner wall of the die is pre-coated with a release agent, a composite emulsion of fluorosilane compounds and mineral oil, with a coating thickness controlled between 10μm and 15μm. This effectively reduces frictional resistance during molding, facilitating subsequent demolding. Molding employs a hydrostatic pressing process, applying a pressure of 12MPa and holding it for 180 seconds to ensure a reasonable distribution of the internal pore structure of the mixture and that the overall density meets design requirements. After molding, the product is removed from the die and immediately transferred to a standard curing room for curing. The curing environment is maintained at a constant temperature of 20℃ and a relative humidity above 95% for a curing period of 7 days.

[0051] After curing, a series of performance tests and characterizations were conducted on the resulting adhesive-bonded permeable pavement panels. Infrared spectroscopy analysis results showed that at a wavenumber of 1730 cm⁻¹... -1 A distinct carbonyl absorption peak was observed at 1080 cm⁻¹, confirming that the polyurethane main chain structure remained intact and undamaged; simultaneously, a peak was observed at 1080 cm⁻¹. -1 A strong Si-O-Si stretching vibration peak was observed, indicating that the amorphous silica-modified shell layer was successfully constructed and may have potential interfacial interactions with the polyurethane adhesive. Furthermore, the product underwent durability testing simulating actual service environments. A total of 15 wet-dry cycle tests were conducted, each cycle consisting of 6 hours of immersion and 18 hours of drying. After the tests, the compressive strength retention rate was greater than 92%. A freeze-thaw cycle test was performed 50 times, each cycle consisting of 4 hours of freezing (at -20°C) and 4 hours of thawing (at 20°C). The final mass loss rate was less than 1.2%, demonstrating excellent environmental adaptability.

[0052] To further optimize the surface functional properties of the product, plasma treatment can be applied to the product surface after static pressing and demolding, and before standard curing begins. The output power of the treatment equipment is set to 300W, and the treatment time is controlled at 60 seconds. By introducing oxygen-containing polar groups, the surface hydrophilicity is moderately improved, which helps to maintain the long-term unobstructed flow of water channels and prevents rainwater retention or blockage due to excessive surface hydrophobicity.

[0053] In this method, the solid waste filler accounts for 18% of the total mass of the mixture, far exceeding the traditional limit of no more than 10%. Even under this high dosage, the measured permeability coefficient of the product still reaches 0.28 mm / s, exceeding the current industry standard limit by 1.8 times, fully verifying the effectiveness of the interface modification strategy. This method is applicable to various scenarios such as urban slow-traffic systems, landscape roads, and ecological parking lots, with a single-day single-line production capacity of up to 800 m², demonstrating significant engineering application value.

[0054] To more intuitively demonstrate the technical effects of this invention, the following provides a set of data comparisons between embodiments and comparative examples: In one specific embodiment, the adhesive-bonded permeable pavement panel was prepared according to all the above-described process steps. The solid waste filler was derived from screened construction waste powder, the coarse aggregate was basalt, and the adhesive system was strictly formulated at a mass ratio of 3:1. After 7 days of standard curing, the resulting product showed a 28-day compressive strength of 38.6 MPa, a permeability coefficient of 0.28 mm / s, a strength retention rate of 93.2% after 15 wet-dry cycles, and a mass loss rate of 1.05% after 50 freeze-thaw cycles.

[0055] As a comparative example, a control sample was prepared using unmodified construction waste micropowder (i.e., omitting the ethyl silicate treatment and heat treatment steps in step 2), with all other process conditions identical. Under the same curing conditions, the compressive strength of this comparative sample was only 29.4 MPa after 28 days, the water permeability coefficient decreased to 0.16 mm / s, the strength retention rate dropped to 84.7% after 15 wet-dry cycles, and the mass loss rate reached 2.38% after 50 freeze-thaw cycles.

[0056] The relevant performance data is summarized in Table 1 below: Table 1 The data clearly demonstrate that constructing an in-situ amorphous silica hydrophobic modified shell on the surface of solid waste particles significantly improves the interfacial bonding between solid waste powder and polyurethane adhesive. This interface optimization not only enhances the overall mechanical properties of the composite material but also effectively suppresses pore blockage caused by excessive adhesive use, thus achieving a simultaneous improvement in water permeability even with high solid waste content. Simultaneously, the densified silica shell acts as a physical barrier, effectively preventing external moisture from penetrating the interfacial region. Under harsh environments such as alternating wet and dry conditions and freeze-thaw cycles, it significantly delays the initiation and propagation of microcracks, endowing the product with excellent long-term durability.

[0057] The method described in this invention demonstrates high repeatability and process controllability in engineering practice. The rotation speed, time, and spray parameters during the high-speed mixing stage can be precisely adjusted through an automated control system; the blade linear velocity and spacing design of the forced twin-shaft mixer ensures the stability of mixing uniformity in large-scale production; the pressure and holding time settings for static pressing balance structural density and pore connectivity; and the standard curing regime provides the necessary conditions for the adhesive to fully crosslink. All key process nodes have clearly defined quantitative control indicators, making this method suitable not only for laboratory pilot tests but also for seamless integration with industrial production lines, enabling the high-value, large-scale utilization of bulk industrial solid waste in road engineering.

[0058] In summary, this invention establishes a complete process system for preparing solid waste-based adhesive-bonded stone permeable pavement by integrating multiple key technologies, including raw material pretreatment, surface chemical modification, precise metering and mixing, efficient molding, and post-treatment enhancement. This system significantly improves the resource utilization rate of industrial solid waste without sacrificing the basic functions of the material, breaking through the bottleneck of limited solid waste content in traditional technical approaches, and providing practical technical support for promoting the development of green and low-carbon building materials.

[0059] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing adhesive-bonded permeable pavement using solid waste-based materials, characterized in that, Includes the following steps: Step 1: Dry solid waste fillers with a particle size of 0.075 mm to 2.36 mm at 105°C for 4 hours; Step 2: Put the dried solid waste filler into a high-speed mixer and pre-stir at 800 r / min for 3 minutes. Then spray in a 12% ethyl silicate ethanol solution, the amount of which is 6% of the mass of the solid waste filler. Under stirring conditions, carry out a sol-gel reaction for 25 minutes to generate an amorphous silica hydrophobic modified shell layer in situ on the surface of the solid waste particles. Step 3: Mix the surface-modified solid waste filler with basalt or diabase coarse aggregate with a particle size of 5mm to 10mm at a mass ratio of 1:4, and mix for 90 seconds in a forced twin-shaft mixer. Step 4: Mix the polyurethane prepolymer and curing agent at a mass ratio of 3:1 to form an organic adhesive. Spray the adhesive evenly onto the mixture at a ratio of 5% of the total mass of the mixture and continue stirring at room temperature for 120 seconds. Step 5: Press the well-mixed material into a static mold at a pressure of 12MPa for 180 seconds. After demolding, cure for 7 days at 20℃ and relative humidity greater than 95% to obtain the adhesive stone permeable pavement panel.

2. The method for preparing adhesive-bonded permeable pavement using solid waste-based materials according to claim 1, characterized in that, The ethyl silicate ethanol solution is sprayed through an atomizing nozzle, with the atomized droplet size ranging from 50 μm to 100 μm.

3. The method for preparing adhesive-bonded permeable pavement using solid waste-based materials according to claim 2, characterized in that, During the sol-gel reaction, the humidity inside the stirring chamber is controlled between 40% and 60%. After the reaction is completed, the product is heat-treated at 400°C for 2 hours.

4. The method for preparing adhesive-bonded permeable pavement using solid waste-based materials according to claim 3, characterized in that, The thickness of the amorphous silica hydrophobic modified shell is 80 nm to 150 nm, and the surface contact angle is 112°.

5. The method for preparing adhesive-bonded permeable pavement using solid waste-based materials according to claim 4, characterized in that, The polyurethane prepolymer is isocyanate-terminated, with a functionality of 2.3 and a number-average molecular weight of 2000; the curing agent is a polyol with a hydroxyl value of 220 mg KOH / g.

6. The method for preparing adhesive-bonded permeable pavement using solid waste-based materials according to claim 5, characterized in that, The organic adhesive is sprayed through a multi-channel spiral nozzle system, with the spray flow rate accuracy controlled within ±2%, and the spray angle covering the entire cross-section of the mixing area.

7. The method for preparing adhesive-bonded permeable pavement using solid waste-based materials according to claim 6, characterized in that, The coarse aggregate is dried at 110°C to a moisture content of less than 0.3% before mixing.

8. The method for preparing adhesive-bonded permeable pavement using solid waste-based materials according to claim 7, characterized in that, The inner wall of the mold used for hydrostatic molding is coated with a release agent formed by a composite emulsion of fluorosilane compounds and mineral oil, with a coating thickness of 10 μm to 15 μm.

9. The method for preparing adhesive-bonded permeable pavement using solid waste-based materials according to claim 8, characterized in that, After curing, the surface of the product is treated with plasma at a power of 300W for 60 seconds.

10. The method for preparing adhesive-bonded permeable pavement using solid waste-based materials according to claim 9, characterized in that, The solid waste filler accounts for 18% of the total mass of the mixture, and the permeability coefficient of the resulting permeable pavement panel is 0.28 mm / s.

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