Light-weight high-strength composite board for modular concrete house and preparation method of light-weight high-strength composite board

Abstract

The invention discloses a lightweight high-strength composite board for a modular concrete house and a preparation method of the lightweight high-strength composite board. The lightweight high-strength composite board comprises a functional surface layer, a lightweight high-strength core layer and a prefabricated structure layer which are sequentially compositely connected from top to bottom, the prefabricated structure layer is a concrete layer reinforced by a prestressed carbon fiber composite material; the light-weight high-strength core layer is a porous material layer with a pore channel structure, and the interior of the light-weight high-strength core layer comprises a large number of micron-sized pore channels which are directionally arranged in the thickness direction; through combination of the prefabricated structure layer and the light-weight high-strength core layer, the overall dry density of the plate is successfully reduced to the ultra-light level of 890 kg / m < 3 > or below, meanwhile, the bending strength of the plate reaches 15 MPa or above, the heat conductivity coefficient is lower than 0.08 W / (m.K) through the high strength and prestress effect of the carbon fiber composite material, and the technical problem that light weight, high strength and high heat preservation cannot be achieved at the same time is solved.

Description

Technical Field

[0001] This invention belongs to the field of building industrialization technology, specifically referring to a lightweight, high-strength composite panel for modular concrete houses and its preparation method. Background Technology

[0002] With the rapid development of industrialized construction, modular concrete houses have attracted much attention due to their advantages such as fast construction speed, controllable quality, and environmental friendliness. The performance of its core components—wall and floor slabs—directly determines the overall building's weight, safety, thermal insulation performance, and construction efficiency. Currently, precast panels commonly found on the market are mainly divided into two categories, but both have significant limitations.

[0003] The first category consists of traditional precast solid or hollow concrete slabs. These slabs rely primarily on the concrete material itself and are reinforced with steel bars. To meet structural strength requirements, their thickness is typically substantial (generally not less than 120mm), resulting in a high self-weight (dry density typically greater than 1800kg / m³). 3 This not only increases transportation and hoisting costs but also places higher demands on the building's foundation. Furthermore, concrete has a high thermal conductivity (approximately 1.5-2.0 W / (m·K)) and poor insulation performance, typically requiring an additional external insulation layer. This increases the number of procedures and construction time, and also poses safety risks such as insulation layer detachment and fire.

[0004] The second category is lightweight insulated composite wall panels, such as sandwich panels with foamed cement, aerated concrete (ALC), or polystyrene foam (EPS) boards as the core material and fiber cement boards on both sides. These panels have achieved progress in both lightweighting and insulation performance. However, the core problem lies in the irreconcilable contradiction between strength, lightweighting, and insulation performance. The porous structure of the core material, while providing insulation, severely weakens its mechanical properties, resulting in generally low bending and impact strength (ALC board compressive strength is approximately 3-5 MPa), typically limiting its use to non-load-bearing enclosure structures. Furthermore, the layers are often assembled physically or bonded, resulting in limited interfacial bonding strength. Under long-term loads or temperature and humidity changes, delamination and cracking are prone to occur, affecting durability. The connection methods are also primarily wet-work, requiring improved assembly efficiency.

[0005] In summary, current technologies lack a comprehensive panel material that can simultaneously meet the requirements of high structural strength for load-bearing capacity, lightweight for transportation and installation, and high thermal insulation for building energy conservation, while also enabling rapid dry assembly. The development of modular buildings urgently needs a new type of composite panel solution that can achieve integrated prefabrication of structure, insulation, and decoration. Summary of the Invention

[0006] To address the needs and problems mentioned in the background above, the present invention provides a lightweight, high-strength composite panel for modular concrete houses and a method for preparing the same, thereby at least partially solving the aforementioned problems.

[0007] According to the technical solution of the present invention, a lightweight high-strength composite panel for modular concrete houses is provided, comprising a functional surface layer, a lightweight high-strength core layer and a prefabricated structural layer connected sequentially from top to bottom; the prefabricated structural layer is a concrete layer reinforced with prestressed carbon fiber composite material; the lightweight high-strength core layer is a porous material layer with a channel structure, which contains a large number of micron-sized channels oriented along the thickness direction.

[0008] Preferably, the concrete in the precast structural layer has a dry density of 800-1200 kg / m³. 3 The lightweight, high-strength concrete, wherein the carbon fiber composite material is embedded in the precast structural layer in the form of a pre-tensioned mesh or reinforcement, so that the concrete layer obtains an effective pre-compression stress of not less than 3MPa.

[0009] Preferably, the lightweight, high-strength core layer is prepared by the ice crystal template method, and its porosity is 70%-90% and its dry density is 100-300 kg / m³. 3 The compressive strength perpendicular to the pore direction is not less than 2MPa.

[0010] Preferably, the prefabricated structural layer and the lightweight high-strength core layer are bonded together by a structural adhesive, and the tensile shear strength of the adhesive layer formed by the structural adhesive is not less than 10 MPa.

[0011] Preferably, the functional surface layer comprises one of a decorative textured thin-layer concrete, a fiber-reinforced cement board, or a polymer-modified mortar layer, and the thickness of the functional surface layer is 5-15 mm.

[0012] Preferably, the plate is provided with metal connectors around its four edges. The connectors are sleeves with internal threads or steel plates with slots, and are pre-embedded and fixed simultaneously during the pouring of the precast structural layer.

[0013] On the other hand, the present invention also provides a method for preparing lightweight high-strength composite panels for modular concrete houses, comprising the following steps: S1: Precast prestressed carbon fiber composite reinforced concrete structural layer: The metal connectors are fixed to the four edges of the mold according to the design position by the positioning clamps, and the tensioned carbon fiber composite mesh is fixed in the mold. Lightweight and high-strength concrete is poured to make the connectors and structural layer integrally formed. S2: A lightweight, high-strength core layer with a porous structure was prepared by combining the ice crystal template method with freeze-drying technology. S3: The lightweight, high-strength core layer is bonded to the upper surface of the structural layer using a structural adhesive; S4: A carbon fiber composite reinforced mesh is laid on the upper surface of the composite lightweight high-strength core layer and a functional surface layer is constructed, followed by overall curing; S5: Perform post-processing, including precision machining and positioning verification of the metal connectors embedded in the edge of the plate to ensure connection accuracy.

[0014] Furthermore, S1 includes the following steps: The carbon fiber composite mesh is tensioned to 60%-80% of its ultimate tensile strength and then fixed in a mold; lightweight high-strength concrete is poured and vibrated to compact it; after steam curing and demolding, it is released under standard curing conditions to obtain prestress.

[0015] Furthermore, S2 includes the following steps: Silicate cement, ultrafine fly ash microspheres, cellulose ether dispersant and water are mixed at a mass ratio of 1:0.5:0.002:6 and stirred at high speed to form a stable suspension slurry. A slurry with a solid content of 10%-25% is prepared and injected into a mold. The temperature at the bottom of the mold is controlled to drop from room temperature to -30°C to -50°C at a constant rate of 5-10°C / min and maintained for 1-2 hours, so that the water in the slurry forms columnar ice crystals that grow in an oriented manner from bottom to top. The completely frozen green body is transferred to a freeze dryer and subjected to sublimation drying for 48-72 hours under conditions of vacuum degree below 10 Pa and cold trap temperature below -50℃ to remove ice crystal template and form a porous green body with directional channels. The porous preform was placed in a curing chamber and cured for 7 days at a temperature of 40℃ and a humidity of 80%. After curing, it was cut according to the design dimensions.

[0016] Furthermore, S4 includes the following steps: A layer of alkali-resistant glass fiber mesh or carbon fiber mesh is laid on the upper surface of the composite core layer; Then, the functional surface material is poured or sprayed, with the flowability controlled at 160-200mm and the thickness at 5-15mm, and the surface is smoothed to form the desired texture.

[0017] The composite panels with the surface layer completed are moved to the curing area and covered for curing for 7-14 days at 20±5℃ and humidity ≥80% to allow each layer of material to reach its final strength and achieve volume stability.

[0018] Beneficial effects: This invention successfully reduces the overall dry density of the board to 890 kg / m³ by combining a prefabricated structural layer with a lightweight, high-strength core layer. 3While achieving the following ultra-lightweight level, the high strength and prestress effect of carbon fiber composite materials enable the bending strength of the plate to reach more than 15MPa and the thermal conductivity to be less than 0.08W / (m·K), solving the technical problem of balancing lightweight, high strength and high thermal insulation. The lightweight, high-strength core layer prepared by the present invention through controlled unidirectional freezing technology has a structure that is not random but optimized along the force transmission path. This not only provides excellent thermal insulation, but its parallel pore walls also form a micro-truss, giving the core material a vertical compressive and shear resistance far exceeding that of similar randomly foamed materials of random density. This allows it to effectively participate in structural stress and form a strong synergy with the structural layer. Detailed Implementation

[0019] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection.

[0020] The embodiments of the present invention provide the following technical solutions: A modular lightweight high-strength composite panel for concrete houses is an integrated sandwich structure consisting of a functional surface layer, a lightweight high-strength core layer, and a prefabricated structural layer, which are sequentially composited from top to bottom. The precast structural layer is a lightweight concrete layer reinforced with prestressed carbon fiber reinforced polymer (CFRP). The dry density of the lightweight concrete is 800-1200 kg / m³. 3 The CFRP has a compressive strength of not less than 40 MPa after 28 days. The CFRP is embedded in the tension side of the concrete layer in the form of a mesh or reinforcement pre-tensioned to 60%-80% of its ultimate tensile strength, so that the concrete layer obtains an effective pre-compression stress of not less than 3 MPa after release.

[0021] The lightweight, high-strength core layer is a porous material layer with a channel structure. This core layer is prepared using an ice crystal template method and contains a large number of micron-sized channels oriented along the thickness direction of the plate or the main stress direction, with a porosity of 70%-90% and a pore size distribution of 10-200 μm. The dry density of this core layer is 100-300 kg / m³. 3 The compressive strength perpendicular to the pore direction is not less than 2MPa, and the thermal conductivity parallel to the pore direction is not higher than 0.05W / (m·K).

[0022] The functional surface layer is a decorative protective layer with a thickness of 5-15mm, including one of the following: textured thin-layer high-performance concrete, fiber-reinforced cement board, or polymer-modified mortar layer.

[0023] The prefabricated structural layer and the lightweight, high-strength core layer are bonded together by a high-performance structural adhesive layer with a thickness of 1-3 mm. The adhesive is an epoxy resin-based or polyurethane-based material with a tensile shear strength of not less than 10 MPa.

[0024] Metal connectors are pre-embedded around the perimeter of the plate. The connectors are either sleeves with internal threads or steel plates with Ω-shaped grooves, which are simultaneously embedded and precisely fixed during the pouring of the precast structural layer.

[0025] On the other hand, embodiments of the present invention also provide a method for preparing the aforementioned lightweight high-strength composite panel for modular concrete houses, comprising the following sequential steps: S1: Precast prestressed CFRP structural layer S1.1: On a dedicated tensioning platform, the CFRP mesh or reinforcing bar is tensioned and anchored at the design stress (60%-80% of its ultimate tensile strength).

[0026] S1.2: Place the tensioned CFRP mesh into a standardized steel mold.

[0027] S1.2.1: The metal connector is fixed to the preset position on the periphery of the mold by means of a detachable positioning fixture - the thread end of the internal threaded sleeve faces outward, the groove direction of the slotted steel plate is consistent with the splicing direction of the plate, the connector fits tightly with the inner wall of the mold, and the positioning error is ≤2mm. S1.2.2: Lay lightweight high-strength concrete with a thickness of 15-30mm at the bottom and around the CFRP grid to ensure that the concrete completely covers the anchoring end of the connector (coverage length ≥20mm) to prevent the connector from loosening. The concrete is made of ceramic sand or vitrified microspheres with a particle size of no more than 5mm as fine aggregate, and the water-cement ratio is controlled at 0.28-0.32.

[0028] S1.3: Compact the concrete using a vibrating table or attached vibrator, followed by steam curing: cure for 12-24 hours at a temperature of 50±5℃ and a humidity of ≥90% to achieve a concrete strength of more than 70% of the design strength.

[0029] S1.4: After demolding, continue curing for 7 days under standard curing conditions of 20±2℃ and humidity ≥95%, and then release the CFRP to give the concrete layer prestress.

[0030] S2: Preparation of a lightweight, high-strength core layer S2.1: Prepare a slurry with a solid content of 10%-25%. Mix silicate cement, ultrafine fly ash microspheres, cellulose ether dispersant and water at a mass ratio of 1:0.5:0.002:6 and stir at high speed until uniform to form a stable suspension slurry.

[0031] S2.2: Inject the slurry into a molding die with a heat-conducting metal plate at the bottom. The thickness of the die is the core layer design thickness (40-100mm).

[0032] S2.3: Place the mold on the freezing platform and start the freezing program: control the temperature at the bottom of the mold to drop from room temperature to -30℃ to -50℃ at a constant rate of 5-10℃ / min, and maintain it for 1-2 hours, so that the water in the slurry forms columnar ice crystals that grow in an oriented manner from bottom to top.

[0033] S2.4: Transfer the completely frozen green body to a freeze dryer and perform sublimation drying for 48-72 hours under conditions of vacuum degree below 10Pa and cold trap temperature below -50℃ to remove ice crystal template and form a porous green body with directional channels.

[0034] S2.5: Place the porous preform in a curing chamber for curing. For cement-based systems, cure for 7 days at 40°C and 80% humidity, then cut to the designed dimensions.

[0035] S3: Composite of core layer and structural layer The high-performance structural adhesive is uniformly coated onto the upper surface of the prefabricated structural layer, with a coating amount of 1.5-2.5 kg / m². 2 .

[0036] Accurately lay the cut lightweight high-strength core layer on the adhesive surface, apply pressure of 0.01-0.05MPa and hold for 2-4 hours to allow the adhesive to initially cure and form a strong interface.

[0037] S4: Construction and overall maintenance of functional surface layers A layer of carbon fiber mesh is laid on the upper surface of the composite core layer.

[0038] Then pour or spray the functional surface material, such as self-leveling high-performance decorative concrete, controlling its flowability to 160-200mm and its thickness to 5-15mm, and smooth the surface to form the desired texture.

[0039] The composite panels with the surface layer completed are moved to the curing area and covered for curing for 7-14 days at 20±5℃ and humidity ≥80% to allow each layer of material to reach its final strength and achieve volume stability.

[0040] S5: Post-processing and Precision machining of embedded parts After curing, remove the side molds and the positioning fixtures on the metal connectors. Use a CNC machine tool to mill and finish the connecting edges of the plates (flatness error ≤ 1mm / m). Clean the exposed parts of the pre-embedded connectors—clean the residual concrete inside the threads of the internal threaded sleeve, grind the burrs on the edge of the slotted steel plate, and then perform positioning verification (center distance error of connectors ≤ 2mm) to ensure splicing accuracy.

[0041] Example 1 Prefabricated structural layers: Mold preparation: Use a standardized steel mold with a flatness error of less than 1mm / 2m, with dimensions of 3000mm×1200mm×30mm (length×width×thickness). Apply a water-based release agent to the inner surface of the mold.

[0042] CFRP tensioning and laying: Place the CFRP mesh with an ultimate tensile strength of 2000MPa and a mesh spacing of 50mm×50mm on a special tensioning platform, use hydraulic jacks to tension it to 1400MPa (70% of the ultimate strength), and lock it to the anchor plates at both ends of the mold to ensure that the mesh is flat and without looseness.

[0043] Concrete pouring: Dry density of the poured concrete is 1100 kg / m³ 3 Lightweight, high-strength concrete.

[0044] The mass ratio of each material is as follows: 400 kg of P.O42.5 cement, 600 kg of ceramsite sand with a particle size of 0-5 mm, 40 kg of silica fume, 5.2 kg of high-performance water-reducing agent, and a water-cement ratio of 0.30. Mix for 3 minutes using a forced mixer, pour evenly into the mold, cover the CFRP mesh, and extend it approximately 10 mm beyond the top.

[0045] Vibration and curing: Use an attached vibrator at a frequency of 100Hz to compact the material until the surface is covered with slurry and free of air bubbles. Then, place the material into a curing kiln and steam-cur it for 18 hours at a temperature of 55±2℃ and a relative humidity of ≥95%.

[0046] Demolding and release: After demolding, the concrete was moved to a standard curing room (20±2℃, humidity ≥95%) for continued curing for 7 days. Then, using a special tool, the locking device of the CFRP was slowly released, completing the transfer of prestress to the concrete structural layer. The effective prestress was measured to be 3.2 MPa.

[0047] Core layer preparation: Slurry preparation: The slurry is prepared according to the following ratio: water: cement: fly ash microspheres: hydroxypropyl methylcellulose (HPMC) = 5.5: 1: 0.5: 0.002 (mass ratio). First, dissolve HPMC in some water, then add cement and fly ash, and mix in a high-speed mixer at 1200 r / min for 5 min to form a uniform and stable suspension slurry with a solid content of 18%.

[0048] Cryogenic molding: The slurry is injected into a polypropylene mold with an inner cavity size of 3000mm×1200mm×80mm. The mold is placed on a copper freezing plate preset to -40℃ and unidirectionally frozen at a cooling rate of about 8℃ / min for 2 hours to form a completely frozen blank with vertically oriented ice crystals.

[0049] Freeze-drying: The frozen preform is quickly transferred to a freeze-drying chamber and sublimated for 60 hours under conditions of vacuum degree ≤10Pa and cold trap temperature -55℃.

[0050] Curing and Cutting: The obtained porous preform was placed in a curing chamber at 40℃ and 80% humidity for 7 days to ensure complete hydration. Finally, it was precisely cut to a size of 2980mm×1180mm×80mm using a diamond saw blade cutter.

[0051] Interlayer composite: On the surface of the cured structural layer, apply a two-component epoxy structural adhesive (A:B=3:1) evenly using a notched trowel, at a rate of 2.0 kg / m². 2 The tooth height is approximately 3mm.

[0052] Lay the cut core layer evenly on the adhesive surface, ensuring alignment on all sides. Apply a pressure of 0.03 MPa using a flat plate pressurizing device and maintain the pressure for 3 hours to allow the adhesive to initially cure and form a strong interface.

[0053] Surface layer construction and maintenance: A 160g / m² layer is laid on the upper surface of the core layer. 2 Carbon fiber mesh fabric.

[0054] A 15mm thick decorative concrete surface layer with a flowability of 180mm is poured. After smoothing, a textured rubber roller is used to roll a wood grain effect onto its surface.

[0055] The entire composite board was moved to the curing area, covered with plastic film, and cured for 10 days at 20±5℃ and humidity ≥85%.

[0056] Post-processing: A five-axis CNC machine tool is used to mill the four sides of the composite board to ensure the perpendicularity and flatness of the edges.

[0057] Before pouring the structural layer, the M16 internal thread stainless steel sleeve is fixed at 300mm and 600mm from the end on the four sides of the mold using positioning clamps. The positioning error is ≤2mm. When pouring concrete, the anchoring end of the sleeve is completely wrapped. In the post-processing stage, only the threads are cleaned and the anchoring is checked.

[0058] Example 2 The difference from Example 1 is as follows: The structural layer concrete has a bulk density of 120 kg / m³. 3 Closed-cell vitrified microspheres replace ceramic sand, reducing the dry density of concrete to 790 kg / m³ 3 During mixing, dry mix first, then add water to prevent the vitrified microspheres from breaking and floating. Use 50Hz low-frequency vibration for compaction to avoid aggregate segregation.

[0059] CFRP tensioning: The tensioning stress is increased to 75% of the ultimate strength (1500MPa).

[0060] Core layer reinforcement: Add 0.5% of the total mass of polypropylene fiber with a length of 12mm to the slurry, mix it evenly with the dry powder first, and then add water and stir.

[0061] Core layer post-curing: After freeze drying, an additional process of curing with 120℃ hot air circulation for 2 hours is added to further enhance the interfacial adhesion between the organic fiber and the inorganic matrix.

[0062] Example 3 The difference from Example 1 is as follows: Core slurry modification: When preparing the slurry, add 10% by weight of silica aerogel powder. The aerogel needs to be premixed with some fly ash before being added to the mixture to avoid agglomeration.

[0063] Freezing process: First, place the mold on a -30℃ freezing plate for 1 hour to form vertical channels at the bottom; then rotate the mold 90° and place it in a -20℃ side cold air freezer for 1 hour to induce the formation of a partially horizontally connected closed-cell structure.

[0064] Surface layer: A 10mm thick fiber-reinforced cement board serves as the surface layer base, covered with a 3mm thick polymer mortar protective layer. The fiber-reinforced cement board is bonded to the core layer by dot-applying polyurethane adhesive.

[0065] Example 4 The difference from Example 1 is as follows: Structural layer: Thickness increased to 40mm. CFRP mesh densified to 30mm×30mm spacing.

[0066] Core layer channel orientation: To provide better horizontal shear resistance, the core layer channel orientation is designed to be horizontal. During fabrication, a vertical mold with copper plate sidewalls is used, and a -35°C cold source is applied from one side of the mold for horizontal unidirectional freezing.

[0067] Surface layer: 15% silicon carbide aggregate with a particle size of 1-3mm is added to the surface concrete to improve wear resistance. The surface layer is mechanically roughened immediately after smoothing to increase the surface friction coefficient.

[0068] Comparative Example 1 Formwork: Prepare a 150mm thick ordinary steel formwork.

[0069] Reinforcing bar binding: Lay and bind double-layer HRB400 steel mesh (Φ8@150mm), with a protective layer thickness of 25mm.

[0070] Casting: The dry density of the cast material is 1450 kg / m³ 3 C30 ceramsite concrete (standard mix, no special additives).

[0071] Vibration curing: Use an immersion vibrator to compact the material. Cover with burlap sacks and water for 28 days.

[0072] Finishing: After demolding, apply a 20mm thick 1:2.5 cement mortar surface layer.

[0073] Comparative Example 2 Prepare two 50mm thick boards with a dry density of 600kg / m³. 3 Autoclaved aerated concrete (ALC) panels.

[0074] Installation of connectors and filling: Place a 50mm thick flame-retardant EPS board (density 18kg / m³) on the base ALC board. 3 Several Φ6 HPB300 steel bars are inserted vertically through the EPS and base plate, with the top exposed.

[0075] Composite upper layer: Cover with a top slab ALC plate, allowing the reinforcing bars to be inserted.

[0076] Grouting fixation: High-strength grout is injected into the grouting holes reserved in the top slab to fill the gaps around the reinforcing bars. After hardening, it forms a keel-type connection.

[0077] Joint treatment: Fill the gaps between boards with special ALC bonding mortar.

[0078] Comparative Example 3 Casting the bottom layer: Pour 30mm thick C40 ordinary concrete into the mold as a structural layer, with Φ4@100mm steel wire mesh inside, and cure for 7 days.

[0079] On-site foaming: A two-component polyurethane foaming agent is sprayed on-site onto the above structural layer, allowing it to freely foam and form an 80mm thick rigid polyurethane foam layer (density 45kg / m³). 3 Its internal pores are completely random closed pores.

[0080] Bonding surface layer: After the foam has cured, apply ordinary construction adhesive to its surface and then attach a 10mm thick cement fiberboard as the surface layer.

[0081] Pressure curing: Press with heavy objects for 24 hours to allow the layers to bond.

[0082] Based on the national standard GB / T23451-2009 "Lightweight Partition Wall Panels for Buildings", experiments were conducted on Examples 1-4 and Comparative Examples 1-3, and the data are shown in Table 1 below: Table 1

[0083] In Table 1 above, C1-C4 correspond to Examples 1-4, and D1-D3 correspond to Comparative Examples 1-3. From the data in the table above, we can see that: All embodiments of the present invention have a dry density ≤890kg / m³ 3 It is only 53%-60% of the weight of the traditional concrete slab in Comparative Example 1, achieving significant weight reduction.

[0084] However, the bending strength is ≥12.5MPa, with a maximum of 19.1MPa, which is 1.5-2.2 times that of Comparative Example 1 and 4-6 times that of Comparative Example 2, thus breaking the traditional contradiction between lightweight and high strength.

[0085] Prestressed CFRP provides high strength and high crack resistance; the core layer is not only lightweight, but its directional hole walls form a micro-truss structure, which can effectively transfer shear force and participate in the overall stress.

[0086] The thermal conductivity of the example is ≤0.095W / (m·K), meeting the requirements for ultra-low energy consumption buildings. Example 3, due to the optimization of aerogel and closed-cell structure, achieves an excellent level of 0.052.

[0087] Compared to 0.210 in Comparative Example 1, the thermal insulation performance is improved by 60%-75%; it is also significantly improved compared to 0.125 in Comparative Example 2.

[0088] The high porosity of the core layer (70%-90%) and the long, orderly channels greatly extend the heat conduction path; the air inside the channels is relatively still, reducing convection.

[0089] The softening coefficient (characterizing water softening resistance) is generally ≥0.82, and the freeze-thaw resistance (mass loss rate after 50 freeze-thaw cycles) is ≤1.5%, far superior to 4.8% of Comparative Example 2 and 3.2% of Comparative Example 3. The hanging force (testing the ability to install heavy components on the wall) is generally ≥1150N. High-performance structural adhesives ensure reliable interfacial chemical bonding; CFRP does not corrode; the biomimetic core skeleton is stable; and the thermal expansion coefficients of each layer are designed and matched to reduce internal stress.

[0090] Comparative Example 1: While reducing the weight by more than 40%, the present invention achieves a 50%-125% increase in flexural strength and an order-of-magnitude improvement in thermal insulation performance.

[0091] Comparative Example 2: Under similar density, the present invention has a bending strength that is 3-5 times higher and a reliable interface bond (with a higher softening coefficient), solving the problems of easy delamination and weak hanging force of ALC boards.

[0092] Comparative Example 3: Under similar thermal insulation performance, the flexural strength of the present invention is 1-2 times higher, and the durability (freeze resistance and water resistance) is significantly better, proving the key contribution of the orientation structure to the mechanical properties.

[0093] In summary, this invention, through the integrated material-structure design of the prestressed CFRP structural layer and the core layer, synergistically leverages the advantages of each component, achieving simultaneous optimization and balanced breakthroughs in multiple key performance aspects such as lightweighting, structural strength, thermal insulation, and durability. Furthermore, the process can be industrialized for prefabrication, and its comprehensive performance far surpasses existing traditional technologies, demonstrating significant technological advancement and broad application value.

[0094] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightweight, high-strength composite panel for modular concrete houses, characterized in that, It comprises a functional surface layer, a lightweight high-strength core layer, and a prefabricated structural layer, which are sequentially connected from top to bottom; the prefabricated structural layer is a concrete layer reinforced with prestressed carbon fiber composite material; the lightweight high-strength core layer is a porous material layer with a channel structure, which contains a large number of micron-sized channels oriented along the thickness direction.

2. The modular lightweight high-strength composite panel for concrete houses according to claim 1, characterized in that, The concrete in the precast structural layer has a dry density of 800-1200 kg / m³. 3 The lightweight, high-strength concrete, wherein the carbon fiber composite material is embedded in the precast structural layer in the form of a pre-tensioned mesh or reinforcement, so that the concrete layer obtains an effective pre-compression stress of not less than 3MPa.

3. The modular lightweight high-strength composite panel for concrete houses according to claim 1, characterized in that, The lightweight, high-strength core layer is prepared using the ice crystal template method, with a porosity of 70%-90% and a dry density of 100-300 kg / m³. 3 The compressive strength perpendicular to the pore direction is not less than 2 MPa.

4. The modular lightweight high-strength composite panel for concrete houses according to claim 1, characterized in that, The prefabricated structural layer and the lightweight high-strength core layer are bonded together by a structural adhesive, and the tensile shear strength of the adhesive layer formed by the structural adhesive is not less than 10 MPa.

5. The modular lightweight high-strength composite panel for concrete houses according to claim 1, characterized in that, The functional surface layer includes one of a decorative textured thin-layer concrete, a fiber-reinforced cement board, or a polymer-modified mortar layer, and the thickness of the functional surface layer is 5-15 mm.

6. The modular lightweight high-strength composite panel for concrete houses according to claim 1, characterized in that, The plate has metal connectors around its four edges. The connectors are either sleeves with internal threads or steel plates with slots, and are pre-embedded and fixed simultaneously during the pouring of the precast structural layer.

7. A method for preparing a lightweight, high-strength composite panel for modular concrete houses as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Precast prestressed carbon fiber composite reinforced concrete structural layer: The metal connectors are fixed to the four edges of the mold according to the design position by the positioning clamps, and the tensioned carbon fiber composite mesh is fixed in the mold. Lightweight and high-strength concrete is poured to make the connectors and structural layer integrally formed. S2: A lightweight, high-strength core layer with a porous structure was prepared by combining the ice crystal template method with freeze-drying technology. S3: The lightweight, high-strength core layer is bonded to the upper surface of the structural layer using a structural adhesive; S4: A carbon fiber composite reinforced mesh is laid on the upper surface of the composite lightweight high-strength core layer and a functional surface layer is constructed, followed by overall curing; S5: Perform post-processing, including precision machining and positioning verification of the metal connectors embedded in the edge of the plate to ensure connection accuracy.

8. The preparation method according to claim 7, characterized in that, S1 includes the following steps: The carbon fiber composite mesh is tensioned to 60%-80% of its ultimate tensile strength and then fixed in a mold; lightweight high-strength concrete is poured and vibrated to compact it; after steam curing and demolding, it is released under standard curing conditions to obtain prestress.

9. The preparation method according to claim 7, characterized in that, S2 includes the following steps: Silicate cement, ultrafine fly ash microspheres, cellulose ether dispersant and water are mixed at a mass ratio of 1:0.5:0.002:6 and stirred at high speed to form a stable suspension slurry. A slurry with a solid content of 10%-25% is prepared and injected into a mold. The temperature at the bottom of the mold is controlled to drop from room temperature to -30°C to -50°C at a constant rate of 5-10°C / min and maintained for 1-2 hours, so that the water in the slurry forms columnar ice crystals that grow in an oriented manner from bottom to top. The completely frozen green body is transferred to a freeze dryer and subjected to sublimation drying for 48-72 hours under conditions of vacuum degree below 10 Pa and cold trap temperature below -50℃ to remove ice crystal template and form a porous green body with directional channels. The porous preform was placed in a curing chamber and cured for 7 days at a temperature of 40℃ and a humidity of 80%. After curing, it was cut according to the design dimensions.

10. The preparation method according to claim 7, characterized in that, S4 includes the following steps: A layer of alkali-resistant glass fiber mesh or carbon fiber mesh is laid on the upper surface of the composite core layer; Then pour or spray the functional surface material, controlling the flowability to be 160-200mm and the thickness to be 5-15mm, and smooth the surface to form the desired texture; The composite panels with the surface layer completed are moved to the curing area and covered for curing for 7-14 days at 20±5℃ and humidity ≥80% to allow each layer of material to reach its final strength and achieve volume stability.

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