Preparation and Construction Process of Cast-in-Place Solid Waste-Based UHPC-Foamed Ceramic Composite Panel

Abstract

This invention relates to the preparation and construction process of a cast-in-place solid waste-based UHPC-foamed ceramic composite board. It utilizes low-grade potassium feldspar tailings, which undergo acid washing activation and plasma-assisted microwave treatment, combined with efficient compounding of solid waste-based raw materials, significantly improving matrix activity and interfacial bonding. A quaternary hybrid toughening system is introduced to comprehensively enhance the material's mechanical properties and crack resistance. The foamed ceramic employs a green manufacturing process, optimizing the pore structure through plasma pretreatment and gradient temperature-controlled sintering, balancing high thermal insulation with structural stability, reducing energy consumption while avoiding the collapse risk of traditional processes. This ensures the interlayer bonding strength and thickness uniformity of the cast-in-place solid waste-based UHPC-foamed ceramic composite board, solving problems such as hollowing and peeling. This technical solution focuses on the high-value utilization of solid waste, combining environmental friendliness and economy, and can replace traditional organic insulation systems, providing a high-strength, durable, and integrated solution for wall insulation buildings, promoting the upgrading of the green building materials industry.

Description

Technical Field

[0001] This invention belongs to the technical field of composite panels, specifically relating to the preparation and construction process of a cast-in-place solid waste-based UHPC-foamed ceramic composite panel. Background Technology

[0002] Wall insulation technology is a way to achieve building energy conservation. A wall insulation system is a general term for a non-load-bearing insulation structure composed of an insulation layer, a protective layer, and fixing materials. It has advantages such as thermal insulation, prevention of thermal bridging, and increased indoor space. However, the main building structure is often subjected to the influence of the natural environment, such as diurnal temperature differences, rain, hail, and frost, causing hot and cold cycles and wet and dry cycles in the insulation system. Therefore, stress will be generated in each structural layer of the wall insulation system. Solar radiation, alkaline corrosion of the materials themselves, and corrosion by external microorganisms can also lead to cracking, hollowing, and peeling of the wall insulation system, affecting the durability of the engineering structure and the aesthetics of the building exterior, and even threatening human safety. UHPC has ultra-durability and can adapt to various complex environments, but the construction of UHPC composite panels with other materials is more difficult: problems such as uneven thickness and unsightly appearance exist.

[0003] Composite panels are boards composed of layers of different materials with different functions. Generally, composite panels consist of a base layer and a finishing layer. The base layer is mostly porous foamed ceramic. While porous foamed ceramic has good thermal insulation, fire resistance, durability, and weather resistance, its mechanical properties are relatively low compared to other types of insulation materials, making it poor as a standalone insulation material. A secondary decorative layer is usually required. There are various types of finishing layers, including sintered microcrystalline glass-porous ceramic integrated panels, which have high energy consumption. Organic composite panel materials are mostly flammable, potentially causing loss of life and property.

[0004] In contrast, cast-in-place UHPC-foamed ceramic composite panels are non-toxic and pollution-free, possess excellent mechanical properties, and offer thermal insulation, making them more advantageous as building insulation materials and giving them a broader market prospect. Typically, an adhesive layer is applied in the middle of the composite panel during its preparation to increase adhesion, bonding strength, and overall performance. Alternatively, an adhesive layer can be omitted. However, omitting the adhesive layer places higher demands on the performance of both the UHPC layer and the foamed ceramic. The UHPC, as the surface layer, is only a few millimeters to centimeters thick, requiring guaranteed bonding strength with the foamed ceramic substrate to prevent delamination or peeling. Compared to traditional concrete, UHPC has a lower water-cement ratio, necessitating a membrane curing process to prevent shrinkage and cracking. The bonding between UHPC and foamed ceramic relies primarily on the inherent bonding properties of UHPC, eliminating the need for mortar or other organic or inorganic adhesives and reducing other complex construction processes. Therefore, due to the difference in thermal expansion coefficients and weak interfacial bonding between UHPC and foamed ceramics, uneven thickness, interlayer delamination, and a rough appearance after construction are prone to occur. Traditional fiber reinforcement methods, such as single toughening fibers, are difficult to balance mechanical properties and durability, and the uneven dispersion of nanophases limits the toughening effect. Conventional foamed ceramic sintering processes result in insufficient decomposition of foaming agents, uneven pore distribution, and failure of foam stabilizers, which can easily lead to structural collapse. Multiple high-temperature treatments are required, resulting in high energy consumption and carbon emission pressure. Therefore, ensuring the adhesion between the UHPC layer and the foamed ceramic layer, overcoming the problems of mechanical properties, durability, and construction compatibility of traditional composite panels, and providing an environmentally friendly and economical solution for high-performance building insulation systems is the focus of this invention. Summary of the Invention

[0005] The purpose of this invention is to provide a preparation and construction process for cast-in-place solid waste-based UHPC-foamed ceramic composite panels.

[0006] To solve the above-mentioned technical problems, the specific process of the present invention is as follows:

[0007] First, low-grade potassium feldspar tailings were placed in a compound solution of 8% citric acid and 2% tartaric acid at a solid-liquid ratio of 1:5. The solution was kept at 60℃ and stirred at 400 rpm for 2 hours to remove impurities through acid washing. Subsequently, the tailings were washed with deionized water until neutral, dried, and calcined for 1 hour using a plasma-assisted microwave calcination system. After calcination, 0.5 wt% sulfonated lignin grinding aid was added for ball milling. The ratio of material to balls to water was [ratio missing].

[0008] =1:1.6:1.0, ball milled at 600 rpm for 4 hours, and simultaneously doped with 0.4-0.8 wt% silane coupling agent KH-550, 0.5 wt% nano alumina and 0.2 wt% β-cyclodextrin for surface modification, filtered and dried to obtain potassium feldspar composite powder;

[0009] Potassium feldspar composite powder was added to the solid waste-based raw material at a dosage of 20-30%, along with 2.8 wt% of a quaternary hybrid system and 2.5 wt% of mixed fibers as a toughening system. The mixture was then ball-milled in a wet ball mill at a stirring speed of 400-600 rpm, a liquid-to-solid ratio of 2:1, and a mixing time of 2 h to obtain UHPC casting mix for later use.

[0010] A base material is made by mixing silica sand, feldspar powder, and industrial waste in a mass ratio of 5:3:2. A composite foaming agent of silicon carbide and 1.5 wt% strontium carbonate is introduced, along with 0.8 wt% nano-clay as a foam stabilizer and 0.5 wt% cerium oxide as a grain boundary strengthener. The raw materials are wet-milled at a stirring speed of 400-600 rpm, with a material:ball:water ratio of 1:1.6:0.8, and a mixing time of 2 hours. Simultaneously, 0.3 wt% polycarboxylate superplasticizer and 0.2 wt% sodium hexametaphosphate dispersant are added to obtain a slurry. The slurry is poured into a mold with a thickness of 4-7 mm and leveled. The slurry undergoes plasma treatment and sintering to obtain foamed ceramics.

[0011] The plasma-assisted microwave calcination system is as follows: under a 10% argon-hydrogen mixed atmosphere, in a stepped power mode, the temperature is increased from 800W to 1200W and then reduced to 800W, with each stage lasting 15 minutes, to achieve microwave calcination at 800℃ for 1 hour.

[0012] The solid waste-based raw material is a composite system of fly ash, water-quenched blast furnace slag and waste concrete aggregate in a mass ratio of 5:3:2, with the particle size crushed to ≤5mm.

[0013] The toughening system is a quaternary hybrid system consisting of 2.0 wt% Fe3O4@SiO2 nanoparticles, 0.2 wt% carbon nanotubes, 0.1 wt% graphene, and 0.5 wt% clay, combined with a mixture of 2.0 wt% basalt fiber and 0.5 wt% polypropylene fiber.

[0014] The slurry undergoes plasma treatment, and the specific sintering process is as follows: first, nitrogen plasma is used at a power density of 1.5 kW / m³. 3 After processing for 10 minutes, an oxygen-nitrogen mixed plasma containing 0.5% oxygen was introduced, with a power density of 2.2 kW / m³. 3 After processing for 8 minutes, sintering was carried out. The sintering process adopted a gradient temperature control mode. The temperature was increased to 850℃ at 8℃ / min for 30 minutes to promote the pre-decomposition of the foaming agent. Then, the temperature was increased to 1180℃ at 4℃ / min and a pulse gas pressure of 0.2MPa with a frequency of 0.5Hz was applied. After holding at this temperature for 40 minutes, two-stage cooling was implemented: nitrogen rapid cooling was used from 1180℃ to 950℃ at a cooling rate of 15℃ / min. After cooling to 950℃, the material was allowed to cool naturally. Finally, foamed ceramics with a thickness of 15-25mm were obtained.

[0015] A preparation and construction process for a cast-in-place solid waste-based UHPC-foamed ceramic composite panel, wherein the construction process of the composite panel is as follows:

[0016] After pouring 2-7mm thick UHPC casting mixture into the prepared pattern mold and leveling it, attach 15-25mm thick foamed ceramic onto the UHPC, vibrate it, cover it with a wooden cover plate, and apply 10-15kg / m² of pressure. 2 This allows the UHPC to bond with the foamed ceramic. After 1 day, remove the membrane, sprinkle water, and allow it to cure naturally for 28 days.

[0017] The beneficial effects of this invention are as follows:

[0018] 1. The cast-in-place solid waste-based UHPC-foamed ceramic composite panel overcomes the three major challenges of traditional composite panels—weak mechanical properties, poor durability, and low construction adaptability—through an innovative interfacial bonding design. In the manufacturing process, the surface modification technology of potassium feldspar composite powder, through the synergistic effect of silane coupling agents and nano-alumina, forms a strong chemical bond network at the interface between the UHPC matrix and the foamed ceramic. Simultaneously, the highly active surface of the foamed ceramic, after plasma activation, achieves seamless integration with the UHPC castable through molecular-level interpenetration, significantly improving interlayer bonding strength. This dual interfacial strengthening mechanism not only solves the problem of easy peeling of traditional adhesive layers but also significantly enhances the overall shear and impact resistance of the composite panel, enabling it to maintain structural integrity under dynamic loads.

[0019] 2. The recycling and innovative technology integration of this low-grade potassium feldspar tailings and solid waste-based raw materials have shown significant advantages in terms of resource utilization, performance optimization and synergistic effects. In particular, the application of grinding aids and nano-toughening systems has broken through the limitations of conventional processes.

[0020] 3. First, the introduction of sulfonated lignin as a grinding aid achieves a breakthrough in efficient grinding and surface modification. Traditional processes often rely on a single grinding aid, while this process uses sulfonated lignin, which not only significantly improves the release efficiency of active components through its dispersing effect, but also forms a synergistic interface modification with silane coupling agents and nano-alumina components. Sulfonated lignin can significantly reduce the agglomeration effect between powder particles and promote particle size homogenization. At the same time, its organic functional groups form chemical bonds with silane coupling agents, strengthening the inorganic-organic interface bonding force. This treatment not only activates the potential activity of tailings, but also greatly improves the dispersibility of powder in the subsequent mixing system, laying a key foundation for the high density and uniformity of the UHPC matrix.

[0021] 4. The synergistic effect of the quaternary hybrid toughening system and the mixed fibers has achieved a breakthrough in the multi-scale crack resistance of UHPC materials. The toughening system effectively disperses external load impacts and inhibits microcrack initiation through interfacial compatibility and stress transfer between multiple components; the directional arrangement and three-dimensional interlaced network of fibers further bridge macroscopic cracks, delaying crack propagation paths. This composite reinforcement mode improves the material's toughness while balancing compressive and flexural strength, giving UHPC both high strength and high crack resistance.

[0022] 5. The introduction of hybrid fibers not only enhances the dynamic load-bearing capacity of UHPC but also significantly improves its fatigue and impact resistance. The complementary effect of these composite fibers forms a multi-level toughening barrier in the matrix, which can improve local tensile strength through the crack-resistant effect of short fibers and enhance the overall structural stability through the continuous network of long fibers. The synergistic effect of sulfonated lignin and the nano-toughening system further optimizes the pore structure and environmental durability of solid waste-based materials, raising the utilization rate of industrial solid waste to a new level while reducing reliance on high-end additives, thus combining environmental protection and economic efficiency.

[0023] 6. Conventional processes often use a single carbonate foaming agent, which suffers from problems such as a narrow foaming temperature window and uncontrollable gas release rate. This process constructs a staged foaming mechanism by combining silicon carbide and strontium carbonate: small-particle-size strontium carbonate decomposes first in the low-temperature region, releasing CO2 to form initial pores, while silicon carbide further reacts in the high-temperature region to generate gas, forming a multi-scale gradient pore structure. The synergistic effect of the two broadens the foaming temperature range, obtaining an ideal structure with uniform pore size distribution and porosity ≥75%.

[0024] 7. Secondly, the composite functionalization of nanoclay and cerium oxide achieves a triple synergistic effect of foaming, foam stabilization, and strengthening. Nanoclay adsorbs onto the bubble interface through its layered structure, inhibiting bubble merging and rupture. Simultaneously, its high specific surface area and the grain boundary segregation effect of cerium oxide form a dual bubble-stabilizing network. Cerium oxide not only inhibits abnormal grain growth by pinning grain boundaries, but its redox properties can also repair oxygen vacancy defects formed at high temperatures. The synergy between the two increases the compressive strength of the material and reduces its high-temperature deformation rate.

[0025] 8. Plasma activation lays the foundation for the high uniformity and high activity of the preform. Nitrogen plasma forms microporous channels on the surface through ion bombardment, and then oxygen-nitrogen mixed plasma generates hydroxyl and carboxyl active groups on the pore walls, thereby increasing the surface energy. This synergistic effect of physical etching and chemical activation enhances the interfacial bonding between the foaming agent and the matrix.

[0026] 9. Secondly, gradient temperature control coupled with pulsed gas pressure sintering achieves refined porosity control. Traditional sintering often uses constant-rate heating, which easily leads to concentrated decomposition of the foaming agent, causing pore structure collapse. This process pre-fires at 8℃ / min to 850℃ to induce pre-decomposition of the foaming agent to form a microporous framework, and then slowly heats at 4℃ / min to 1180℃ combined with 0.2MPa pulsed gas pressure, stabilizing the closed-pore ratio and concentrating the pore size distribution. Compared with conventional processes without gas pressure intervention, pore size uniformity is improved and compressive strength is increased. Nitrogen quenching rapidly solidifies the glass phase in the 1180℃ to 950℃ range, locking the pore wall structure and inhibiting grain coarsening; subsequent slow cooling eliminates residual stress through viscoelastic relaxation, reducing the peak thermal stress. The rapid cooling for shaping and slow cooling for stress relief significantly reduces water absorption, lowering it compared to conventional single-stage cooling processes, while simultaneously enhancing compressive strength. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the wall insulation system of the present invention. Figure 1 . Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the embodiments.

[0029] Example 1

[0030] First, low-grade potassium feldspar tailings were placed in a compound solution of 8% citric acid and 2% tartaric acid at a solid-liquid ratio of 1:5. The solution was kept at 60℃ and stirred at 400rpm for 2 hours to remove impurities through acid washing. Then, the tailings were washed with deionized water until neutral, dried, and subjected to a plasma-assisted microwave calcination system. Under a 10% argon-hydrogen mixed atmosphere, the temperature was increased from 800W to 1200W and then decreased to 800W in a stepped power mode, with each stage lasting 15 minutes, achieving microwave calcination at 800℃ for 1 hour. After calcination, 0.5wt% sulfonated lignin grinding aid was added for ball milling (material:ball:water = 1:1.6:1.0), and ball milling was performed at 600rpm for 4 hours. Simultaneously, 0.6wt% silane coupling agent KH-550, 0.5wt% nano-alumina, and 0.2wt% β-cyclodextrin were added for surface modification. After filtration and drying, potassium feldspar composite powder was obtained.

[0031] The solid waste-based raw material is a composite system of fly ash, water-quenched blast furnace slag, and waste concrete aggregate in a mass ratio of 5:3:2. The particle size is crushed to ≤5mm. Potassium feldspar composite powder is added to the solid waste-based raw material at a dosage of 25%. 2.0wt% Fe3O4@SiO2 nanoparticles, 0.2wt% carbon nanotubes, 0.1wt% graphene, and 0.5wt% clay are added to form a quaternary hybrid system. A mixture of 2.0wt% basalt fiber and 0.5wt% polypropylene fiber is then mixed and ball-milled in a wet ball mill at a stirring speed of 500rpm, a liquid-to-solid ratio of 2:1, and a mixing time of 2h to obtain the UHPC casting mix for later use.

[0032] Example 2

[0033] First, low-grade potassium feldspar tailings were placed in a compound solution of 8% citric acid and 2% tartaric acid at a solid-liquid ratio of 1:5. The solution was kept at 60℃ and stirred at 400rpm for 2 hours to remove impurities through acid washing. Then, the tailings were washed with deionized water until neutral, dried, and subjected to a plasma-assisted microwave calcination system. Under a 10% argon-hydrogen mixed atmosphere, the temperature was increased from 800W to 1200W and then decreased to 800W in a stepped power mode, with each stage lasting 15 minutes, achieving microwave calcination at 800℃ for 1 hour. After calcination, 0.5wt% sulfonated lignin grinding aid was added for ball milling (material:ball:water = 1:1.6:1.0), and ball milling was performed at 600rpm for 4 hours. Simultaneously, 0.4wt% silane coupling agent KH-550, 0.5wt% nano-alumina, and 0.2wt% β-cyclodextrin were added for surface modification. After filtration and drying, potassium feldspar composite powder was obtained.

[0034] The solid waste-based raw material is a composite system of fly ash, water-quenched blast furnace slag, and waste concrete aggregate in a mass ratio of 5:3:2. The particle size is crushed to ≤5mm. Potassium feldspar composite powder is added to the solid waste-based raw material at a dosage of 20%. 2.0wt% Fe3O4@SiO2 nanoparticles, 0.2wt% carbon nanotubes, 0.1wt% graphene, and 0.5wt% clay are added to form a quaternary hybrid system. A mixture of 2.0wt% basalt fiber and 0.5wt% polypropylene fiber is then mixed and ball-milled in a wet ball mill at a stirring speed of 600rpm, a liquid-to-solid ratio of 2:1, and a mixing time of 2h to obtain the UHPC casting mix for later use.

[0035] Example 3

[0036] First, low-grade potassium feldspar tailings were placed in a compound solution of 8% citric acid and 2% tartaric acid at a solid-liquid ratio of 1:5. The solution was kept at 60℃ and stirred at 400rpm for 2 hours to remove impurities through acid washing. Then, the tailings were washed with deionized water until neutral, dried, and subjected to a plasma-assisted microwave calcination system. Under a 10% argon-hydrogen mixed atmosphere, the temperature was increased from 800W to 1200W and then decreased to 800W in a stepped power mode, with each stage lasting 15 minutes, achieving microwave calcination at 800℃ for 1 hour. After calcination, 0.5wt% sulfonated lignin grinding aid was added for ball milling (material:ball:water = 1:1.6:1.0), and ball milling was performed at 600rpm for 4 hours. Simultaneously, 0.8wt% silane coupling agent KH-550, 0.5wt% nano-alumina, and 0.2wt% β-cyclodextrin were added for surface modification. After filtration and drying, potassium feldspar composite powder was obtained.

[0037] The solid waste-based raw material is a composite system of fly ash, water-quenched blast furnace slag, and waste concrete aggregate in a mass ratio of 5:3:2. The particle size is crushed to ≤5mm. Potassium feldspar composite powder is added to the solid waste-based raw material at a dosage of 30%. 2.0wt% Fe3O4@SiO2 nanoparticles, 0.2wt% carbon nanotubes, 0.1wt% graphene, and 0.5wt% clay are added to form a quaternary hybrid system. This is combined with a mixture of 2.0wt% basalt fiber and 0.5wt% polypropylene fiber and then ball-milled in a wet ball mill at a stirring speed of 400rpm, a liquid-to-solid ratio of 2:1, and a mixing time of 2h to obtain the UHPC casting mix for later use.

[0038] Comparative Example 1

[0039] The difference between this comparative example and Example 1 is that low-grade potassium feldspar tailings are directly added in this comparative example. The specific process is as follows: the solid waste base raw material adopts a composite system of fly ash, water-quenched blast furnace slag and waste concrete aggregate in a mass ratio of 5:3:2, and the particle size is crushed to ≤5mm. Low-grade potassium feldspar tailings are added to the solid waste base raw material, and the amount of low-grade potassium feldspar tailings is 25%. 2.0wt% Fe3O4@SiO2 nanoparticles, 0.2wt% carbon nanotubes, 0.1wt% graphene and 0.5wt% clay are added to form a quaternary hybrid system. 2.0wt% basalt fiber and 0.5wt% polypropylene fiber are mixed together and ball-milled in a wet ball mill at a stirring speed of 500rpm, a liquid-to-solid ratio of 2:1 and a mixing time of 2h to obtain UHPC casting mix for later use.

[0040] Comparative Example 2

[0041] The difference between this comparative example and Example 1 is that sulfonated lignin is replaced with triethanolamine in this comparative example, otherwise it is the same as Example 1.

[0042] Comparative Example 3

[0043] The difference between this comparative example and Example 1 is that no composite fiber is added in this comparative example. The specific process is as follows:

[0044] First, low-grade potassium feldspar tailings were placed in a compound solution of 8% citric acid and 2% tartaric acid at a solid-liquid ratio of 1:5. The solution was kept at 60℃ and stirred at 400rpm for 2 hours to remove impurities through acid washing. Then, the tailings were washed with deionized water until neutral, dried, and subjected to a plasma-assisted microwave calcination system. Under a 10% argon-hydrogen mixed atmosphere, the temperature was increased from 800W to 1200W and then decreased to 800W in a stepped power mode, with each stage lasting 15 minutes, achieving microwave calcination at 800℃ for 1 hour. After calcination, 0.5wt% sulfonated lignin grinding aid was added for ball milling (material:ball:water = 1:1.6:1.0), and ball milling was performed at 600rpm for 4 hours. Simultaneously, 0.6wt% silane coupling agent KH-550, 0.5wt% nano-alumina, and 0.2wt% β-cyclodextrin were added for surface modification. After filtration and drying, potassium feldspar composite powder was obtained.

[0045] The solid waste-based raw material is a composite system of fly ash, water-quenched blast furnace slag, and waste concrete aggregate in a mass ratio of 5:3:2. The particle size is crushed to ≤5mm. Potassium feldspar composite powder is added to the solid waste-based raw material at a dosage of 25%. 2.0wt% Fe3O4@SiO2 nanoparticles, 0.2wt% carbon nanotubes, 0.1wt% graphene, and 0.5wt% clay are added to form a quaternary hybrid system. The mixture is then ball-milled in a wet ball mill at a stirring speed of 500rpm, a liquid-to-solid ratio of 2:1, and a mixing time of 2h to obtain the UHPC casting mix for later use.

[0046] Comparative Example 4

[0047] First, low-grade potassium feldspar tailings were placed in a compound solution of 8% citric acid and 2% tartaric acid at a solid-liquid ratio of 1:5. The solution was kept at 60℃ and stirred at 400rpm for 2 hours to remove impurities through acid washing. Then, the tailings were washed with deionized water until neutral, dried, and subjected to a plasma-assisted microwave calcination system. Under a 10% argon-hydrogen mixed atmosphere, the temperature was increased from 800W to 1200W and then decreased to 800W in a stepped power mode, with each stage lasting 15 minutes, achieving microwave calcination at 800℃ for 1 hour. After calcination, 0.5wt% sulfonated lignin grinding aid was added for ball milling (material:ball:water = 1:1.6:1.0), and ball milling was performed at 600rpm for 4 hours. Simultaneously, 0.6wt% silane coupling agent KH-550, 0.5wt% nano-alumina, and 0.2wt% β-cyclodextrin were added for surface modification. After filtration and drying, potassium feldspar composite powder was obtained.

[0048] The solid waste-based raw material is a composite system of fly ash, water-quenched blast furnace slag, and waste concrete aggregate in a mass ratio of 5:3:2. The particle size is crushed to ≤5mm. Potassium feldspar composite powder is added to the solid waste-based raw material at a dosage of 25%. 2.0wt% Fe3O4@SiO2 nanoparticles, 0.2wt% carbon nanotubes, 0.1wt% graphene, and 0.5wt% clay are added to form a quaternary hybrid system. Combined with 2.0wt% basalt fiber, the mixture is ball-milled in a wet ball mill at a stirring speed of 500rpm, a liquid-to-solid ratio of 2:1, and a mixing time of 2h to obtain the UHPC casting mix for later use.

[0049] Comparative Example 5

[0050] First, low-grade potassium feldspar tailings were placed in a compound solution of 8% citric acid and 2% tartaric acid at a solid-liquid ratio of 1:5. The solution was kept at 60℃ and stirred at 400rpm for 2 hours to remove impurities through acid washing. Then, the tailings were washed with deionized water until neutral, dried, and subjected to a plasma-assisted microwave calcination system. Under a 10% argon-hydrogen mixed atmosphere, the temperature was increased from 800W to 1200W and then decreased to 800W in a stepped power mode, with each stage lasting 15 minutes, achieving microwave calcination at 800℃ for 1 hour. After calcination, 0.5wt% sulfonated lignin grinding aid was added for ball milling (material:ball:water = 1:1.6:1.0), and ball milling was performed at 600rpm for 4 hours. Simultaneously, 0.6wt% silane coupling agent KH-550, 0.5wt% nano-alumina, and 0.2wt% β-cyclodextrin were added for surface modification. After filtration and drying, potassium feldspar composite powder was obtained.

[0051] The solid waste-based raw material is a composite system of fly ash, water-quenched blast furnace slag and waste concrete aggregate in a mass ratio of 5:3:2. The particle size is crushed to ≤5mm. Potassium feldspar composite powder is added to the solid waste-based raw material at a dosage of 25%. 2.0wt% basalt fiber and 0.5wt% polypropylene fiber mixture are added and ball-milled in a wet ball mill at a stirring speed of 500rpm, a liquid-to-solid ratio of 2:1 and a mixing time of 2h to obtain UHPC casting mix for later use.

[0052] Experiment 1: UHPC Performance Test

[0053] The above UHPC mixture was poured into a mold with a thickness of 5 mm, leveled, and then 12 kg / m² was applied. 2 The weight will be determined after molding and drying, and the properties will be tested. Compressive strength: Refer to GB / T31387-2015. Elastic modulus: Refer to GB / T31387-2015.

[0054] The results are shown in Table 1 below.

[0055] Table 1

[0056] Group compressive strength (MPa) Elastic modulus GPa Example 1 138.4 53.9 Example 2 138.1 52.4 Example 3 137.8 52.0 Comparative Example 1 125.3 46.2 Comparative Example 2 129.6 48.3 Comparative Example 3 130.5 47.5 Comparative Example 4 133.4 50.7 Comparative Example 5 131.6 48.1

[0057] Example 4

[0058] A base material was prepared by mixing silica sand, feldspar powder, and industrial waste in a mass ratio of 5:3:2. A composite foaming agent of silicon carbide and strontium carbonate (2 wt%) was introduced, along with 0.8 wt% nano-clay as a foam stabilizer and 0.5 wt% cerium oxide as a grain boundary strengthener. The raw materials were wet-milled at a stirring speed of 500 rpm (material:ball:water = 1:1.6:0.8) for 2 hours. Simultaneously, 0.3 wt% polycarboxylate superplasticizer and 0.2 wt% sodium hexametaphosphate dispersant were added to obtain a slurry. The slurry was poured into a 5 mm thick mold and leveled. The slurry underwent plasma treatment, first with nitrogen plasma at a power density of 1.5 kW / m³. 3 After processing for 10 minutes, an oxygen-nitrogen mixed plasma containing 0.5% oxygen was introduced, with a power density of 2.2 kW / m³. 3 After processing for 8 minutes, sintering was carried out. The sintering process adopted a gradient temperature control mode. The temperature was increased to 850℃ at 8℃ / min for 30 minutes to promote the pre-decomposition of the foaming agent. Then, the temperature was increased to 1180℃ at 4℃ / min and a pulse gas pressure of 0.2MPa with a frequency of 0.5Hz was applied. After holding at this temperature for 40 minutes, two-stage cooling was implemented: nitrogen rapid cooling was used from 1180℃ to 950℃ at a cooling rate of 15℃ / min. After cooling to 950℃, the material was allowed to cool naturally, and finally, a foamed ceramic with a thickness of 20mm was obtained.

[0059] Example 5

[0060] A base material was prepared by mixing silica sand, feldspar powder, and industrial waste in a mass ratio of 5:3:2. A composite foaming agent of silicon carbide and 1.5 wt% strontium carbonate was introduced, along with 0.8 wt% nano-clay as a foam stabilizer and 0.5 wt% cerium oxide as a grain boundary strengthener. The raw materials were wet-milled at a stirring speed of 400 rpm, with a material:ball:water ratio of 1:1.6:0.8, for 2 hours. Simultaneously, 0.3 wt% polycarboxylate superplasticizer and 0.2 wt% sodium hexametaphosphate dispersant were added to obtain a slurry. The slurry was injected into a 7 mm thick mold and leveled. The slurry underwent plasma treatment, first with nitrogen plasma at a power density of 1.5 kW / m³. 3 After processing for 10 minutes, an oxygen-nitrogen mixed plasma containing 0.5% oxygen was introduced, with a power density of 2.2 kW / m³. 3After processing for 8 minutes, sintering was carried out. The sintering process adopted a gradient temperature control mode. The temperature was increased to 850℃ at 8℃ / min for 30 minutes to promote the pre-decomposition of the foaming agent. Then, the temperature was increased to 1180℃ at 4℃ / min and a pulse gas pressure of 0.2MPa with a frequency of 0.5Hz was applied. After holding at this temperature for 40 minutes, two-stage cooling was implemented: nitrogen rapid cooling was used from 1180℃ to 950℃ at a cooling rate of 15℃ / min. After cooling to 950℃, the material was allowed to cool naturally, and finally, a foamed ceramic with a thickness of 25mm was obtained.

[0061] Example 6

[0062] A base material was prepared by mixing silica sand, feldspar powder, and industrial waste in a mass ratio of 5:3:2. A composite foaming agent of silicon carbide and 1.5 wt% strontium carbonate was introduced, along with 0.8 wt% nano-clay as a foam stabilizer and 0.5 wt% cerium oxide as a grain boundary strengthener. The raw materials were wet-milled at a stirring speed of 600 rpm, with a material:ball:water ratio of 1:1.6:0.8, for a mixing time of 2 hours. Simultaneously, 0.3 wt% polycarboxylate superplasticizer and 0.2 wt% sodium hexametaphosphate dispersant were added to obtain a slurry. The slurry was poured into a 4 mm thick mold and leveled. The slurry underwent plasma treatment, first with nitrogen plasma at a power density of 1.5 kW / m³. 3 After processing for 10 minutes, an oxygen-nitrogen mixed plasma containing 0.5% oxygen was introduced, with a power density of 2.2 kW / m³. 3 After processing for 8 minutes, sintering was carried out. The sintering process adopted a gradient temperature control mode. The temperature was increased to 850℃ at 8℃ / min for 30 minutes to promote the pre-decomposition of the foaming agent. Then, the temperature was increased to 1180℃ at 4℃ / min and a pulse gas pressure of 0.2MPa with a frequency of 0.5Hz was applied. After holding at this temperature for 40 minutes, two-stage cooling was implemented: nitrogen rapid cooling was used from 1180℃ to 950℃ at a cooling rate of 15℃ / min. After cooling to 950℃, the material was allowed to cool naturally, and finally, a foamed ceramic with a thickness of 15mm was obtained.

[0063] Comparative Example 6

[0064] The difference between this comparative example and Example 4 is that 2 wt% silicon carbide is added as a foaming agent in this comparative example; the rest is the same as in Example 4.

[0065] Comparative Example 7

[0066] The difference between this comparative example and Example 4 is that 0.5 wt% cerium oxide is not added in this comparative example, while the rest is the same as in Example 4.

[0067] Comparative Example 8

[0068] A base material was prepared by mixing silica sand, feldspar powder, and industrial waste in a mass ratio of 5:3:2. A composite foaming agent of silicon carbide and 1.5 wt% strontium carbonate was introduced, along with 0.8 wt% nano-clay as a foam stabilizer and 0.5 wt% cerium oxide as a grain boundary strengthener. The raw materials were wet-milled at a stirring speed of 500 rpm, with a material:ball:water ratio of 1:1.6:0.8, for a mixing time of 2 hours. Simultaneously, 0.3 wt% polycarboxylate superplasticizer and 0.2 wt% sodium hexametaphosphate dispersant were added to obtain a slurry. The slurry was then injected... The material is leveled in a 5mm thick mold and then sintered. The sintering process uses a gradient temperature control mode. The temperature is increased to 850℃ at 8℃ / min for 30min to promote the pre-decomposition of the foaming agent. Then, the temperature is increased to 1180℃ at 4℃ / min and a pulsed gas pressure of 0.2MPa at a frequency of 0.5Hz is applied. After holding at this temperature for 40min, two-stage cooling is performed: nitrogen rapid cooling is used from 1180℃ to 950℃ at a cooling rate of 15℃ / min. The material is then allowed to cool naturally at 950℃. Finally, a foamed ceramic with a thickness of 20mm is obtained.

[0069] Comparative Example 9

[0070] A base material was prepared by mixing silica sand, feldspar powder, and industrial waste in a mass ratio of 5:3:2. A composite foaming agent of silicon carbide and strontium carbonate (2 wt%) was introduced, along with 0.8 wt% nano-clay as a foam stabilizer and 0.5 wt% cerium oxide as a grain boundary strengthener. The raw materials were wet-milled at a stirring speed of 500 rpm (material:ball:water = 1:1.6:0.8) for 2 hours. Simultaneously, 0.3 wt% polycarboxylate superplasticizer and 0.2 wt% sodium hexametaphosphate dispersant were added to obtain a slurry. The slurry was poured into a 5 mm thick mold and leveled. The slurry underwent plasma treatment, first with nitrogen plasma at a power density of 1.5 kW / m³. 3 After processing for 10 minutes, an oxygen-nitrogen mixed plasma containing 0.5% oxygen was introduced, with a power density of 2.2 kW / m³. 3 After processing for 8 minutes, sintering was carried out by heating to 1180℃ at a rate of 5℃ / min and applying a pulsed gas pressure of 0.2MPa at a frequency of 0.5Hz. After holding at this temperature for 40 minutes, two-stage cooling was performed: nitrogen rapid cooling was used from 1180℃ to 950℃ at a rate of 15℃ / min, and the temperature was allowed to cool naturally at 950℃. Finally, a foamed ceramic with a thickness of 18mm was obtained.

[0071] Experiment 2: Performance Testing of Foamed Ceramic

[0072] The experiment used a digital camera to observe the pore structure of the cross-section of the foamed ceramic samples. Five local areas, each 5cm x 3cm, were randomly selected, and the average pore diameter was measured. The bulk density, apparent porosity, and water absorption of the samples were determined according to GB / T5486-2008 "Test Methods for Inorganic Rigid Thermal Insulation Products", and the thermal conductivity was determined according to GB / T10294-2008 using a THQDC-1 thermal conductivity meter from Zhejiang Tianhuang Technology Co., Ltd.

[0073] The bulk density of the specimen was measured using the Archimedes displacement method. The compressive strength of the specimen was tested using a universal testing machine (AG-XPLUS250KN) with a descent rate of 0.5 mm / min. The compressive strength of the specimen was calculated according to formula (1).

[0074] σ=P / S (1)

[0075] Where: σ—compressive strength of the specimen, MPa;

[0076] P—The maximum pressure the specimen can withstand before breakage, in N;

[0077] S—The area of ​​the specimen subjected to pressure, in mm 2 ;

[0078] The results are shown in Table 2 below.

[0079] Table 2

[0080]

[0081] A 4mm thick UHPC casting mixture prepared in Examples 1-3 and Comparative Examples 1-5 was poured into the prepared pattern mold and leveled. Then, foamed ceramics prepared in Examples 4-6 and Comparative Examples 6-9 were attached to the UHPC, vibrated, and covered with a wooden cover. At the same time, 12kg / m³ of material was applied. 2 This process allows UHPC to bond with foamed ceramics. After one day, the film is removed, and five samples are prepared for each group to test the performance of the composite board.

[0082] Experiment 3: Composite Board Performance

[0083] A pull-out test was conducted on a composite plate sample. One end of the sample was fixed, and the other end was bonded to the sample surface with high-strength epoxy adhesive. A tensile force was applied to the sample at a constant rate of 2 mm / min. When the sample failed, the force and displacement at failure were recorded. Failure could be material fracture, peeling of the bonded surface, or other forms of failure. The maximum load-bearing capacity was calculated: the maximum force the sample could withstand before failure, which is the bonding performance, and the average value was taken. The data results are shown in Table 3. The fracture strength was tested according to GB / T 3810.4-2016. The thermal conductivity was measured using a THQDC-1 thermal conductivity meter from Zhejiang Tianhuang Technology Co., Ltd., according to GB / T10294-2008. The results are shown in Table 3.

[0084] Table 3

[0085]

[0086]

Claims

1. A preparation process of cast-in-place solid waste-based UHPC-foamed ceramic composite board, characterized in that: The cast-in-situ solid waste-based UHPC is: First, the low-grade potassium feldspar tailings were prepared and placed in a solution of 8% citric acid and 2% tartaric acid, with a solid-liquid ratio of 1:5, constant temperature of 60°C, and stirring at 400 rpm for 2 hours to complete the acid pickling and impurity removal. Then, the tailings were washed with deionized water until neutral, dried, and calcined in a plasma-assisted microwave calcination system for 1 hour. After calcination, 0.5wt% sulfonated lignin grinding aid was added for ball milling treatment, with a material:ball:water ratio of 1:1.6:1.0, ball milling at 600 rpm for 4 hours. Simultaneously, 0.4-0.8wt% silane coupling agent KH-550, 0.5wt% nano-alumina, and 0.2wt% beta-cyclodextrin were added for surface modification. After filtration and drying, the potassium feldspar composite powder was obtained. The potassium feldspar composite powder was added to the solid waste-based raw material, with a potassium feldspar composite powder content of 20-30%. A four-component hybrid system was introduced, with 2.8wt% of the four-component hybrid system and 2.5wt% of the mixed fibers as the toughening system. Wet ball milling was performed at a stirring rate of 400-600 rpm, with a liquid-solid ratio of 2:1 and a mixing time of 2 hours. The UHPC casting mixture was obtained and ready for use. A mixture of silica sand, feldspar powder, and industrial waste slag was prepared with a mass ratio of 5:3:

2. 2wt% silicon carbide and 1.5wt% strontium carbonate were introduced as composite foaming agents. 0.8wt% nano-clay was added as a foam stabilizer, and 0.5wt% cerium oxide was added as a grain boundary strengthening agent. The raw materials were wet ball milled at a stirring rate of 400-600 rpm, with a material:ball:water ratio of 1:1.6:0.8 and a mixing time of 2 hours. 0.3wt% polycarboxylic acid water reducer and 0.2wt% sodium hexametaphosphate dispersant were added simultaneously to obtain the slurry. The slurry was injected into a mold with a thickness of 4-7 mm and leveled. The slurry was treated with plasma, and the sintered foam ceramic was obtained. The plasma-assisted microwave calcination system is as follows: under a 10% argon-hydrogen mixed gas atmosphere, the power was increased from 800W to 1200W and then decreased to 800W, with each stage lasting 15 minutes. The microwave calcination was performed at 800°C for 1 hour. The solid waste-based raw material is a composite system of fly ash, water-quenched blast furnace slag, and waste concrete aggregate with a mass ratio of 5:3:2, and the particle size is crushed to ≤5mm. The toughening system is a four-component hybrid system composed of 2.0wt% Fe3O4@SiO2 nanoparticles, 0.2wt% carbon nanotubes, 0.1wt% graphene, and 0.5wt% clay. It is combined with 2.0wt% basalt fibers and 0.5wt% polypropylene fibers. The slurry undergoes plasma treatment, and the specific sintering process is as follows: first, nitrogen plasma is used at a power density of 1.5 kW / m³. 3 After processing for 10 minutes, an oxygen-nitrogen mixed plasma containing 0.5% oxygen was introduced, with a power density of 2.2 kW / m³. 3 After processing for 8 minutes, sintering was carried out. The sintering process adopted a gradient temperature control mode. The temperature was increased to 850℃ at 8℃ / min for 30 minutes to promote the pre-decomposition of the foaming agent. Then, the temperature was increased to 1180℃ at 4℃ / min and a pulse gas pressure of 0.2MPa with a frequency of 0.5Hz was applied. After holding at this temperature for 40 minutes, two-stage cooling was implemented: nitrogen rapid cooling was used from 1180℃ to 950℃ at a cooling rate of 15℃ / min. After cooling to 950℃, the material was allowed to cool naturally. Finally, foamed ceramics with a thickness of 15-25mm were obtained.

2. The preparation process of cast solid waste-based UHPC-foamed ceramic composite board according to claim 1, characterized in that, The preparation process of the composite board is as follows: pour 2-7mm of UHPC casting mixture into the prepared pattern mold and level it. Then, attach the foam ceramic with a thickness of 15-25mm to the UHPC. Vibrate, cover with a wooden cover, and apply 10-15kg / m² to bond the UHPC and foam ceramic. After 1 day, remove the mold and water, and naturally cure for 28 days.

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