Prefabricated lightweight high-strength multifunctional bare ceramsite concrete, external wall panel prepared from same and preparation process

Abstract

The invention provides prefabricated lightweight high-strength multifunctional bare ceramsite concrete, an external wall panel prepared from the concrete and a preparation process of the concrete. The concrete adopts functional ceramsite with a double-layer structure, wherein the inner core is lightweight ceramsite, and the outer layer is coated with a heat-insulating coating or contains a microcapsule phase-change material; a gelling system adopts cement and high-content fly ash / slag powder, and is supplemented with nano reinforcing agents such as nano SiO2 and graphene oxide as well as fibers for reinforcement; and a bubble agent is introduced to form a microporous structure, so that the density is greatly reduced while the strength is maintained. The plate manufacturing process is combined with vacuum / vibration compaction, microwave accelerated curing and other measures, the production efficiency is remarkably improved, and energy conservation and consumption reduction are achieved. The density of the manufactured wallboard is 1.5-1.6 g / cm < 3 >, the compressive strength is larger than or equal to 25 MPa, the heat conductivity coefficient is smaller than or equal to 0.15 W / (m.K), A-level fire prevention is achieved, the wallboard has the light weight, the high heat preservation performance and the clear water decoration effect, the mechanical strength and durability are remarkably improved, and the wallboard is suitable for green fabricated buildings.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building materials, in particular to a prefabricated lightweight high-strength multifunctional dry-finished ceramsite concrete, a wallboard prepared therefrom and a preparation process. BACKGROUND

[0002] Traditional ceramsite concrete is widely used in the field of construction due to its low density and porous structure. Its inherent lightweight and thermal insulation properties can reduce the self-weight of the building and improve energy-saving effects. Ceramsite is mainly made of clay, shale or fly ash and other materials sintered at high temperature, and has the characteristics of spherical or granular shape, internal porosity, rough surface, light weight and certain strength. Its corrosion resistance, freeze-thaw resistance, shock resistance and good thermal insulation performance have been recognized by the industry. Studies have shown that the use of ceramsite to replace part of the ordinary aggregate can reduce the self-weight of the concrete by about 25%, and effectively improve the thermal insulation performance and durability of the concrete. At present, there are various lightweight thermal insulation ceramsite concrete and prefabricated wallboard technologies at home and abroad, such as achieving thermal insulation effect through ceramsite concrete sandwich insulation board, or chemically modifying ceramsite to improve strength and thermal insulation.

[0003] However, the existing technology still has the following shortcomings: first, the thermal insulation, fire resistance or durability of ordinary ceramsite concrete cannot meet the requirements of high-performance buildings for multiple functions; second, traditional aggregate mainly uses natural sand and stone, ignoring the resource utilization of industrial by-products, and has low environmental protection; third, in order to ensure strength, more cementitious materials need to be added, resulting in increased specific gravity and large carbon emissions; fourth, the existing panel preparation process is mostly manual operation, and the degree of automation is low, the production efficiency and product quality stability need to be improved. In view of these problems, the technical field urgently needs a new type of ceramsite concrete formula and preparation process, which takes into account ultralight, high strength, multifunctionality and green and sustainable characteristics, in order to meet the requirements of modern building energy saving, environmental protection and structural performance. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a prefabricated lightweight high-strength multifunctional dry-finished ceramsite concrete, a wallboard prepared therefrom and a preparation process, which has a density of 1.5-1.6 g / cm 3 , a compressive strength of ≥25 MPa, a thermal conductivity of ≤0.15 W / (m·K) and A-level fireproofing, and has the advantages of lightweight, high thermal insulation and dry-finished decoration, and is suitable for green prefabricated buildings.

[0005] The present application is implemented as follows:

[0006] A prefabricated lightweight high-strength multifunctional dry-finished ceramsite concrete, comprising the following components by weight:

[0007] Cementitious materials: cement, fly ash and slag powder, 100-200 parts;

[0008] Fine aggregate: fine sand or expanded lightweight aggregate, 200-400 parts;

[0009] Functional expanded clay aggregate: Double-layer composite structure expanded clay aggregate, 100-200 parts; its core has a density of 600-900 kg / m³. 3 The core of the ceramic pellets is covered with an outer heat-insulating coating containing paraffin phase change material or silica powder.

[0010] Fiber-reinforced materials: glass fiber, basalt fiber or carbon fiber, 0.5 to 5 parts;

[0011] Functional additives: expanded graphite, silicate expander, 0.5-5 parts;

[0012] Auxiliary materials: high-efficiency water-reducing agent and waterproofing agent, 1 to 10 parts.

[0013] Furthermore, in the cementitious material:

[0014] The cement is P·O42.5 or P·O52.5 ordinary Portland cement; the fly ash is Grade I or Grade II fly ash with a loss on ignition ≤5%; the slag powder is Grade S95 or Grade S105 slag powder; the total mass of fly ash and slag powder is 20% to 50% of the cement mass.

[0015] Furthermore, in the aggregate:

[0016] The fine sand has a fineness modulus of 2.3-3.0 and a mud content of ≤3%; the expanded lightweight aggregate is expanded perlite or expanded vermiculite with a particle size of 3mm-6mm and a bulk density of ≤300kg / m³. 3 .

[0017] Furthermore, in the functional ceramsite: the core particle size is 10-25 mm, and the water absorption rate is ≤5%; the paraffin phase change microcapsules in the outer coating have a phase change temperature of 20-30℃ and a particle size of 5-50 μm;

[0018] In the fiber-reinforced material: the fiber length is 12-24 mm and the diameter is 13-17 μm;

[0019] The functional additives include: expanded graphite with an expansion volume ≥ 200 mL / g and a particle size of 100-200 mesh.

[0020] Furthermore, the cementitious material also includes: a nano-reinforcing agent: nano-SiO2 or graphene oxide, accounting for 1% to 5% of the mass of the cementitious material;

[0021] The auxiliary materials also include: foaming agents and stabilizers.

[0022] Furthermore, the preparation of the functional ceramsite includes:

[0023] (1) Pretreatment of ceramsite core: The ceramsite core is soaked in 1mol / L dilute hydrochloric acid for 10-30 minutes, then neutralized with alkaline solution, and repeatedly washed until neutral;

[0024] The coating layer consists of paraffin-based phase change microcapsules prepared by in-situ polymerization, with a particle size of 5–50 μm.

[0025] (2) Loading and curing of functional coating layer: Paraffin wax is used as phase change material, and urea and polyoxymethylene are used as shell material. The particle size of the prepared paraffin wax-based phase change microcapsules is 5-50 μm. The ceramic core is immersed in the paraffin wax-based phase change microcapsule solution for 120 min-240 min, and then placed in an oven at 50-65℃ to dry.

[0026] The preparation method of paraffin-based phase change microcapsules is as follows: Paraffin-based phase change microcapsules contain the following raw materials in the following mass percentages: paraffin 25-35%; urea 2.5-4%; formaldehyde 4-6%; sodium tripolyphosphate 0.05-0.25%; sodium dodecylbenzenesulfonate 1.5-2.5%; deionized water 65-75%;

[0027] Sodium dodecylbenzenesulfonate was added to deionized water and stirred until completely dissolved. Paraffin wax was melted and added to the solution. The solution temperature was maintained at 40–50°C, and the mixture was stirred at a speed of 4000–6000 rpm for 40–60 minutes. Meanwhile, urea and formaldehyde were mixed and stirred slowly at 40–50°C until homogeneous. This mixture was then added to the previously prepared solution and stirred at 50–70°C at a speed of 400–600 rpm for 150–240 minutes to obtain the wax-based phase change microcapsule solution.

[0028] Furthermore, a precast exterior wall panel prepared from the aforementioned precast lightweight high-strength multifunctional fair-faced ceramsite concrete has a panel thickness of 80-150mm, is integrally cast from the ceramsite concrete, has a compressive strength ≥25MPa, a thermal conductivity ≤0.20W / (m·K), and thermal stability that meets the Class A fire resistance standard.

[0029] Furthermore, a fiber mesh or steel mesh reinforcement layer is embedded inside the plate, which is integrally cast with the concrete.

[0030] Furthermore, a manufacturing process for the aforementioned prefabricated exterior wall panel includes the following steps:

[0031] (1) Dry material premixing: mixing cement, fly ash, slag powder, nano-reinforcing agent and fiber;

[0032] (2) Slurry preparation: Add water and high-efficiency water-reducing agent and stir evenly to form slurry;

[0033] (3) Mixing: Gradually add functional ceramsite and fine aggregate, and mix using planetary high-speed shearing;

[0034] (4) Vibration degassing: After the mixture is injected into the mold, it is degassed by vacuum / mechanical vibration and the surface is scraped smooth;

[0035] (5) Accelerate curing: Microwave or infrared heating of the mold, curing time ≤30 minutes;

[0036] (6) Demolding: After curing, cool and demold, then heat treat or polish the surface to form a clear decorative surface.

[0037] Furthermore, in step (3), a vacuum degassing device is used to simultaneously remove air to ensure that the nanomaterials and functional ceramic particles are evenly dispersed;

[0038] In step (4), local heating can be performed simultaneously during the compaction step to improve the density.

[0039] The present invention has the following advantages:

[0040] 1. Preparation and Application of Functional Expanded Ceramsite: Expanded ceramsite cores are prepared using industrial waste (such as fly ash, steel slag, and tailings sludge) as raw materials. After acid-alkali or high-temperature activation treatment, a porous activation layer forms on the surface of the expanded ceramsite core. A layer of phase change material microcapsules is then coated onto the surface of the expanded ceramsite, forming a double-layer composite expanded ceramsite. This functional expanded ceramsite possesses both lightweight and high-strength load-bearing capacity, and can significantly enhance the thermal insulation performance of walls through phase change, meeting the decorative requirements of fair-faced concrete (i.e., a natural texture visible without coating), thus achieving integration of structure and decoration.

[0041] 2. High-strength lightweight aggregate system: This system uses graded ceramsite core as aggregate, combined with a small amount of expanded lightweight aggregate. The density of the ceramsite core can be controlled between 600 and 900 kg / m³. The surface of the aggregate particles can be pre-coated with nano-silica slurry to increase the bonding force with cement paste, thus maintaining high strength while achieving low density. Utilizing foaming agent technology, a fine and uniform closed-pore system is formed, further reducing the self-weight of the concrete. However, reinforcement with fibers and nano-minerals prevents strength loss due to excessively large pores.

[0042] 3. Composite Cementitious System and Sustainable Raw Materials: The preferred cementitious material is a blend of cement with a high proportion of fly ash and slag powder, utilizing industrial byproducts to replace part of the cement, thereby reducing carbon emissions and costs. Simultaneously, nano-scale admixtures such as nano-SiO2, silica fume, or graphene oxide are added to improve hydration density and micro-interfacial bonding strength, further enhancing strength and durability. A small amount of active mineral admixtures and high-efficiency water-reducing agents are added to achieve a lower water-cement ratio (e.g., 0.3-0.4) to improve the early strength and flexural strength of the concrete.

[0043] 4. Synergistic Design with Multiple Functions: To achieve composite functions such as thermal insulation, fireproofing, and durability, expanded graphite and silicate insulating fibers (such as glass fiber and basalt fiber) are added to the formula. Expanded graphite forms a heat insulation layer at high temperatures, enhancing fire resistance; the waterproofing agent improves impermeability and service life. The synergistic effect of the dual reinforcement of nanomaterials and fibers effectively controls cracks in the microporous structure, significantly improving the crack resistance and long-term durability of concrete.

[0044] 5. Innovative Manufacturing Process: A combination of a high-shear planetary mixer and a vibratory vacuum assembly table ensures uniform dispersion of nanomaterials and functional ceramsite. During raw material mixing, viscous components (nano-silicon, fibers, etc.) are added first to form a uniform colloid, followed by the gradual addition of water. Finally, ceramsite and expanding materials are injected and vibrated to degas the mixture. After casting, vacuum and mechanical demolding technologies are used to rapidly release air and improve density. Microwave, infrared heating, or hot air curing methods are employed to achieve modular and rapid curing. The mold is a reusable high-strength steel mold with a silane release agent coating, allowing for automatic flipping and demolding, suitable for robotic operation.

[0045] 6. Precast Panel Structure and Advantages: The exterior wall panels feature a seamless, fair-faced finish. No independent insulation core layer is incorporated within the panels; instead, homogeneous insulation is achieved within the concrete using functional expanded clay aggregates and composite fillers (expanded lightweight aggregate, expanded graphite, etc.). The panel thickness can be designed within the range of 80–150 mm, meeting both structural strength and insulation requirements. Thanks to its composite material design, the wall panels possess Class A fire resistance, low thermal conductivity, high strength (compressive strength exceeding 30 MPa), and excellent impermeability and frost resistance (impermeability grade P8, frost resistance grade F50). Engineering tests show that these wall panels are approximately 20-30% lighter than traditional concrete panels, with significantly improved insulation performance, facilitating the application of next-generation green building wall systems.

[0046] In summary, this invention, through the compounding of functional ceramsite, the utilization of industrial solid waste raw materials, and multi-layer reinforcement technology, balances the requirements of lightweight, high strength, and multifunctionality. Compared with existing technologies, the technical solution of this invention has the following advantages: reducing the self-weight of the wall panel and lowering the overall cost; significantly improving thermal insulation and fire resistance durability; effectively utilizing industrial by-products and reducing carbon emissions, thus conforming to the trend of energy conservation and environmental protection.

Detailed Implementation Methods

[0047] This invention relates to a precast lightweight, high-strength, multifunctional fair-faced ceramsite concrete, comprising the following components in parts by weight:

[0048] Cementitious materials: cement, fly ash and slag powder, 100-200 parts;

[0049] Fine aggregate: fine sand and expanded lightweight aggregate, 200-400 parts;

[0050] Functional expanded clay: Double-layer composite expanded clay, 100-200 parts; its core is an expanded clay core with a density of 600-900 kg / m3, and the outer layer is covered with a heat-insulating coating containing paraffin phase change material or silica powder.

[0051] Fiber-reinforced materials: glass fiber, basalt fiber or carbon fiber, 0.5 to 5 parts;

[0052] Functional additives: expanded graphite, silicate expander, 0.5-5 parts;

[0053] Auxiliary materials: high-efficiency water-reducing agent and waterproofing agent, 1 to 10 parts.

[0054] In a preferred embodiment, the cementitious material contains:

[0055] The cement is P·O42.5 or P·O52.5 ordinary Portland cement; the fly ash is Grade I or Grade II fly ash with a loss on ignition ≤5%; the slag powder is Grade S95 or Grade S105 slag powder; the total mass of fly ash and slag powder is 20% to 50% of the cement mass.

[0056] In a preferred embodiment, the aggregate contains:

[0057] The fine sand has a fineness modulus of 2.3-3.0 and a mud content of ≤3%; the expanded lightweight aggregate is expanded perlite or expanded vermiculite with a particle size of 3mm-6mm and a bulk density of ≤300kg / m³. 3 .

[0058] In a preferred embodiment, the functional ceramsite has the following characteristics: the core particle size is 10-25 mm, the compressive strength is 3.5-5 MPa, and the water absorption rate is ≤5%; the paraffin phase change microcapsules in the outer coating have a phase change temperature of 20-30℃ and a particle size of 5-50 μm.

[0059] In the fiber-reinforced material: the fiber length is 12-24 mm and the diameter is 13-17 μm;

[0060] The functional additives include: expanded graphite with an expansion volume ≥ 200 mL / g and a particle size of 100-200 mesh.

[0061] In a preferred embodiment, the cementitious material further includes a nano-reinforcing agent.

[0062] Nano-SiO2 or graphene oxide accounts for 1% to 5% of the mass of the cementitious material;

[0063] The auxiliary materials also include: foaming agents and stabilizers.

[0064] In a preferred embodiment, the preparation of the functional ceramsite includes:

[0065] (1) Pretreatment of ceramsite core: The ceramsite core is soaked in 1 mol / L dilute hydrochloric acid for 10 to 30 minutes, then neutralized with alkaline solution, and repeatedly washed until neutral; the coating layer is paraffin-based phase change microcapsules prepared by in-situ polymerization with a particle size of 5 to 50 μm.

[0066] (2) Loading and curing of functional coating layer: Paraffin wax is used as phase change material, and urea and polyoxymethylene are used as shell material. The particle size of the prepared paraffin wax-based phase change microcapsules is 5-50 μm. The ceramic core is immersed in the paraffin wax-based phase change microcapsule solution for 120 min-240 min, and then placed in an oven at 50-65℃ to dry.

[0067] The preparation method of paraffin-based phase change microcapsules is as follows: Paraffin-based phase change microcapsules contain the following raw materials in the following mass percentages: paraffin 25-35%; urea 2.5-4%; formaldehyde 4-6%; sodium tripolyphosphate 0.05-0.25%; sodium dodecylbenzenesulfonate 1.5-2.5%; deionized water 65-75%;

[0068] Sodium dodecylbenzenesulfonate was added to deionized water and stirred until completely dissolved. Paraffin wax was melted and added to the solution. The solution temperature was maintained at 40–50°C, and the mixture was stirred at a speed of 4000–6000 rpm for 40–60 minutes. Meanwhile, urea and formaldehyde were mixed and stirred slowly at 40–50°C until homogeneous. This mixture was then added to the previously prepared solution and stirred at 50–70°C at a speed of 400–600 rpm for 150–240 minutes to obtain the wax-based phase change microcapsule solution.

[0069] This invention also relates to a precast exterior wall panel made of precast lightweight high-strength multifunctional fair-faced ceramsite concrete. The exterior wall panel has a thickness of 80-150mm, is integrally cast from the ceramsite concrete, has a compressive strength ≥25MPa, a thermal conductivity ≤0.20W / (m·K), and its thermal stability meets the Class A fire resistance standard.

[0070] In a preferred embodiment, the plate is reinforced with a fiber mesh or steel mesh and is integrally cast with the concrete.

[0071] This invention also relates to the manufacturing process of the aforementioned prefabricated exterior wall panels, comprising the following steps:

[0072] (1) Dry material premixing: mixing cement, fly ash, slag powder, nano-reinforcing agent and fiber;

[0073] (2) Slurry preparation: Add water and high-efficiency water-reducing agent and stir evenly to form slurry;

[0074] (3) Mixing: Gradually add functional ceramsite and fine aggregate, and mix using planetary high-speed shearing;

[0075] (4) Vibration degassing: After the mixture is injected into the mold, it is degassed by vacuum / mechanical vibration and the surface is scraped smooth;

[0076] (5) Accelerate curing: Microwave or infrared heating of the mold, curing time ≤30 minutes;

[0077] (6) Demolding: After curing, cool and demold, then heat treat or polish the surface to form a clear decorative surface.

[0078] In a preferred embodiment, step (3) involves using a vacuum degassing device to simultaneously remove air to ensure uniform dispersion of nanomaterials and functional ceramic particles.

[0079] In step (4), local heating can be performed simultaneously during the compaction step to improve the density.

[0080] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0081] Example 1:

[0082] Preparation of slurry: 120 parts of cement P·O 42.5, 20 parts of fly ash, 30 parts of slag powder, 3 parts of nano-silica, and 1.5 parts of polycarboxylate superplasticizer are thoroughly mixed in a high-shear mixer. Preparation of functional ceramsite: Industrial waste such as fly ash and slag are pretreated to produce ceramsite cores with a diameter of 10-20 mm and a density of approximately 800 kg / m³. The ceramsite cores are impregnated in a slurry containing phase change microcapsules (paraffin phase change materials) to form a thin layer on their surface. Then, the surface is sprayed or calcined for curing to obtain double-layer ceramsite with a microporous phase change phase.

[0083] Mix proportions (parts by weight): 120 parts cement, 20 parts fly ash, 30 parts slag powder, 150 parts functional ceramsite (precast), 150 parts fine sand, 80 parts crushed stone, 20 parts expanded lightweight aggregate, 2 parts chopped glass fiber, 3 parts nano-SiO2, 2 parts expanded graphite (fire retardant), 0.5 parts silane coupling agent, 1.5 parts polycarboxylate superplasticizer, and 75 parts water. Add an appropriate amount of latex waterproofing agent to the concrete.

[0084] The cement used is P·O42.5 silicate cement; the fly ash is Grade I with a loss on ignition ≤5%; the slag powder is Grade S95; the fineness modulus of the fine sand is 2.3-3.0 with a mud content ≤3%; and the expanded lightweight aggregate has a particle size of 3mm-6mm and a bulk density ≤300kg / m³. 3 The functional ceramsite comprises: a core particle size of 10-25 mm and a water absorption rate of ≤5%; a paraffin phase change microcapsule particle size of 5-50 μm in the outer coating; a fiber-reinforced material with a fiber length of 12-24 mm and a diameter of 13-17 μm; and a functional additive with an expanded graphite expansion volume ≥200 mL / g and a particle size of 100-200 mesh.

[0085] Construction Process: First, mix cement, fly ash, slag powder, nano-SiO2, fibers, and other dry materials evenly. Then, add water and water-reducing agent and stir for several minutes. Finally, add functional ceramsite and fine aggregate and mix evenly. Deaerate and mold on a vibrating table. After pouring, level the surface with a scraper and continue compacting with a vacuum deaeration system. After molding, cure in a high-temperature steam autoclave for 5 hours, or use microwave high-speed curing for 30 minutes. After demolding, a 100mm thick exterior wall panel is obtained, with a compressive strength of over 30MPa, a specific gravity of approximately 1.6g / cm3, and a thermal conductivity of approximately 0.15W / (m·K). Its thermal insulation performance is significantly higher than that of unmodified concrete, and its surface is smooth and delicate, making it suitable for direct use as a decorative surface.

[0086] Example 2:

[0087] The raw material composition is the same as in Example 1, and its automated production process is as follows: An automated batching and mixing module of the formula of this invention is set up on a large precast component production line. The control system pre-sets the raw material ratio and adds them to the mixer in sequence; the mixer works by integrating rollers and vacuum vibration to simultaneously remove excess air during the bubble mixing stage. Then, a robotic arm injects the mixture into a placed steel mold, and a microwave heating device or infrared lamp drying component is arranged around the mold for curing. After curing, the robot automatically uses demolding tools (such as a robotic arm or mechanical flipper) to remove the formed wall panel. The entire process requires no manual intervention, improving production efficiency and safety.

[0088] In summary, the concrete of this invention employs an innovative double-layer structure of functional expanded clay aggregate: the core is lightweight expanded clay aggregate, with an outer layer coated with a heat-insulating coating, or containing microencapsulated phase change materials; the cementitious system uses cement + sustainable materials such as high-volume fly ash / slag powder, supplemented with nano-reinforcing agents such as nano-SiO2 and graphene oxide, and fiber (such as basalt fiber) reinforcement; and an air-bubbling agent is introduced to form a microporous structure, significantly reducing density while maintaining strength. The panel manufacturing process combines automated mixing, recyclable molds, vacuum / vibration compaction, and microwave accelerated curing, significantly improving production efficiency and saving energy. The resulting wall panels are lightweight (density 1.5–1.6 g / cm³). 3 It possesses multiple properties such as high strength (compressive strength ≥25MPa), Class A fire resistance, excellent thermal insulation (thermal conductivity 0.15W / (m·K)), and durability, meeting the requirements for the decorative effect of fair-faced concrete. Compared with existing technologies, this invention comprehensively utilizes functional expanded clay aggregates, composite materials, and advanced processes, resulting in a weight reduction of approximately 25% while significantly improving thermal insulation, mechanical strength, and durability.

[0089] The materials and their contents described in this invention can be adjusted appropriately according to specific application requirements; all proportions are merely examples. Without departing from the spirit of this invention, performance can be further improved by replacing environmentally friendly materials or optimizing aggregate gradation. The results of the above embodiments demonstrate that the prefabricated exterior wall panels prepared using the technical solution of this invention have a uniform and dense structure, high strength, and stable quality. Their lightweight, high-strength, and multifunctional characteristics are superior to traditional concrete panels.

[0090] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A precast lightweight, high-strength, multifunctional fair-faced ceramsite concrete, characterized in that: Includes the following components by weight: Cementitious materials: cement, fly ash and slag powder, 100-200 parts; Fine aggregate: fine sand or expanded lightweight aggregate, 200-400 parts; Functional expanded clay aggregate: Double-layer composite structure expanded clay aggregate, 100-200 parts; its core has a density of 600-900 kg / m³. 3 The core of the ceramic aggregate is coated with an outer layer containing a paraffin-containing phase change material; Fiber-reinforced materials: glass fiber, basalt fiber or carbon fiber, 0.5 to 5 parts; Functional additives: expanded graphite, silicate expander, 0.5-5 parts; Auxiliary materials: high-efficiency water-reducing agent and waterproofing agent, 1 to 10 parts.

2. The expanded clay concrete according to claim 1, characterized in that: In the cementitious material: The cement is P·O42.5 or P·O52.5 ordinary Portland cement; the fly ash is Grade I or Grade II fly ash with a loss on ignition ≤5%; the slag powder is Grade S95 or Grade S105 slag powder; the total mass of fly ash and slag powder is 20% to 50% of the cement mass.

3. The expanded clay concrete according to claim 1, characterized in that: In the aggregate: The fine sand has a fineness modulus of 2.3-3.0 and a mud content of ≤3%; the expanded lightweight aggregate is expanded perlite or expanded vermiculite with a particle size of 3mm-6mm and a bulk density of ≤300kg / m³. 3 .

4. The expanded clay concrete according to claim 1, characterized in that: The functional ceramsite has the following characteristics: the core particle size is 10-25 mm and the water absorption rate is ≤5%; the outer coating contains paraffin phase change microcapsules with a phase change temperature of 20-30℃ and a particle size of 5-50 μm. In the fiber-reinforced material: the fiber length is 12-24 mm and the diameter is 13-17 μm; The functional additives include: expanded graphite with an expansion volume ≥ 200 mL / g and a particle size of 100-200 mesh.

5. The expanded clay concrete according to claim 1, characterized in that: The cementitious material also includes: nano-reinforcing agent: nano-SiO2 or graphene oxide, accounting for 1% to 5% of the mass of the cementitious material; The auxiliary materials also include: foaming agents and stabilizers.

6. The expanded clay concrete according to claim 1, characterized in that: The preparation of the functional ceramsite includes: (1) Pretreatment of ceramsite core: The ceramsite core is soaked in 1mol / L dilute hydrochloric acid for 10-30 minutes, then neutralized with alkaline solution, and repeatedly washed until neutral; The coating layer consists of paraffin-based phase change microcapsules prepared by in-situ polymerization, with a particle size of 5–50 μm. (2) Loading and curing of functional coating layer: Paraffin wax is used as phase change material, and urea and polyoxymethylene are used as shell material. The particle size of the prepared paraffin wax-based phase change microcapsules is 5-50 μm. The ceramic core is immersed in the paraffin wax-based phase change microcapsule solution for 120 min-240 min, and then placed in an oven at 50-65℃ to dry. The preparation method of paraffin-based phase change microcapsules is as follows: Paraffin-based phase change microcapsules contain the following raw materials in the following mass percentages: paraffin 25-35%; urea 2.5-4%; formaldehyde 4-6%; sodium tripolyphosphate 0.05-0.25%; sodium dodecylbenzenesulfonate 1.5-2.5%; deionized water 65-75%; Sodium dodecylbenzenesulfonate was added to deionized water and stirred until completely dissolved. Paraffin wax was melted and added to the solution. The solution temperature was maintained at 40–50°C, and the mixture was stirred at a speed of 4000–6000 rpm for 40–60 minutes. Meanwhile, urea and formaldehyde were mixed and stirred slowly at 40–50°C until homogeneous. This mixture was then added to the previously prepared solution and stirred at 50–70°C at a speed of 400–600 rpm for 150–240 minutes to obtain the wax-based phase change microcapsule solution.

7. A precast exterior wall panel prepared from precast lightweight high-strength multifunctional fair-faced ceramsite concrete according to any one of claims 1-6, characterized in that: The thickness of the exterior wall panel is 80-150mm, and the panel is integrally cast from the ceramsite concrete. The compressive strength is ≥25MPa, the thermal conductivity is ≤0.20W / (m·K), and the thermal stability meets the Class A fire protection standard.

8. The precast exterior wall panel prepared from precast lightweight high-strength multifunctional fair-faced ceramsite concrete according to claim 7, characterized in that: The plate is reinforced with a fiber mesh or steel mesh and is cast integrally with the concrete.

9. A manufacturing process for a prefabricated exterior wall panel according to claim 7, characterized in that: Includes the following steps: (1) Dry material premixing: mixing cement, fly ash, slag powder, nano-reinforcing agent and fiber; (2) Slurry preparation: Add water and high-efficiency water-reducing agent and stir evenly to form slurry; (3) Mixing: Gradually add functional ceramsite and fine aggregate, and mix using planetary high-speed shearing; (4) Vibration degassing: After the mixture is injected into the mold, it is degassed by vacuum / mechanical vibration and the surface is scraped smooth; (5) Accelerate curing: Microwave or infrared heating of the mold, curing time ≤30 minutes; (6) Demolding: After curing, cool and demold, then heat treat or polish the surface to form a clear decorative surface.

10. The preparation process according to claim 9, characterized in that: Step (3) uses a vacuum degassing device to simultaneously remove air to ensure uniform dispersion of nanomaterials and functional ceramic particles; In step (4), local heating can be performed simultaneously during the compaction step to improve the density.