Basalt fiber cement-based composite gradient functional material forming device and method

Abstract

The invention discloses a basalt fiber cement-based composite gradient functional material forming device and method, and belongs to the technical field of building material additive manufacturing. The device comprises a main material extrusion bin, at least two sub-material stirring bins, a driving device, a radar level gage and a control system. The functional slurry is stirred and then injected into the sub-material stirring bins for temporary storage, and the top of each sub-material stirring bin is provided with a radar level gage for monitoring the uniformity and rheological property of the slurry in real time. And the control system independently starts each bin blocking device according to a preset gradient model sequence, so that slurry with different functions sequentially flows into the main material extrusion bin, the slurry is extruded and printed layer by layer after being subjected to secondary homogenization and re-checking, the main material bin is emptied after each layer is printed, and the multifunctional gradient composite component with the functions of bearing, sound absorption, heat preservation, decoration and the like is formed. The fiber volume mixing amount is distributed in a stepped mode, continuous transition of performance is achieved, and interface stress is relieved. The method is suitable for key infrastructure construction in severe environments such as open sea islands and reefs.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology for building materials, and in particular to a molding device and method for basalt fiber cement-based composite gradient functional materials. Background Technology

[0002] Functionally graded materials (FGMs) eliminate the distinct internal interfaces present in traditional composite materials through continuous spatial variations in composition and microstructure, thereby effectively alleviating thermal stress and avoiding abrupt performance changes. Introducing the FGM concept into cement-based materials can theoretically significantly improve their inherent defects, such as low tensile strength (typically only 1 / 10 of compressive strength), high brittleness, and limited functionality (e.g., only load-bearing capacity, unable to simultaneously meet requirements for thermal insulation, sound insulation, and decoration).

[0003] However, research on cement-based composite gradient functional materials is still in its early stages, lacking mature dedicated molding equipment. Traditional preparation methods rely on manual mixing and layered casting with other media, resulting in outdated processes, low efficiency, and difficulty in precisely controlling interlayer gradient distribution and bonding quality. In recent years, the development of 3D concrete printing technology has made layered extrusion of cement-based materials possible, but existing 3D printing equipment generally suffers from the following drawbacks: (1) It is only compatible with a single material and cannot automatically switch and accurately supply multiple different types of pastes in a single printing process; (2) The lack of online real-time monitoring of the slurry mixing degree and rheological state makes it impossible to ensure that each layer of material is extruded under the best process conditions; (3) Abrupt interface between different material layers and lack of gradual transition design of composition result in insufficient interlayer bonding strength and easy cracking.

[0004] Therefore, developing a dedicated molding device and process capable of precise supply of multiple materials, online status monitoring, and gradient transition control is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a molding device and method for basalt fiber cement-based composite gradient functional materials, which solves the problems of outdated traditional cement-based gradient functional material preparation processes, inability to achieve automatic switching of multiple materials, lack of online status monitoring and gradient transition control.

[0006] In a first aspect, the present invention provides a molding apparatus for basalt fiber cement-based composite gradient functional materials, comprising: The main material extrusion chamber is equipped with a main material mixing screw inside, and a printing nozzle is connected to its bottom; At least two sub-material mixing chambers are fixedly installed above the main material extrusion chamber. Each sub-material mixing chamber has an independent inlet, outlet, and sub-material mixing screw. The outlet is connected to the main material extrusion chamber through a flow controllable blocking device. The first driving device is used to drive the sub-material mixing screw to rotate; The second drive unit is used to drive the main material mixing screw to rotate. The first material level monitoring module is installed at the top of each sub-material mixing bin to monitor the material level height and mixing status of the slurry in the bin in real time. The mixing status includes the uniformity and rheology of the slurry. The second material level monitoring module is located in the channel between the discharge port of the main material extrusion chamber and the printing nozzle, and is used to perform a final state check on the slurry that is about to enter the printing nozzle. The control system is electrically connected to the blocking device, the first driving device, the second driving device, the first material level monitoring module, and the second material level monitoring module, respectively. The control system is configured to: execute a preset printing task, control the mixing process of each sub-material mixing chamber according to the feedback signal of the first material level monitoring module, open each blocking device in sequence or proportion according to the preset gradient structure model, and decide whether to allow extrusion printing according to the verification result of the second material level monitoring module.

[0007] Preferably, there are four sub-material mixing chambers, and the four sub-material mixing chambers are welded and fixed inside or around the main material extrusion chamber; the sub-material mixing screw and the main material mixing screw are interchangeable to adapt to the mixing requirements of different materials.

[0008] Preferably, both the first and second level monitoring modules are radar level gauges, which determine the uniformity and rheological state of the slurry by emitting high-frequency electromagnetic waves to the slurry surface and analyzing the signal stability and fluctuation amplitude of the reflected echo.

[0009] Secondly, the present invention provides a method for molding basalt fiber cement-based composite gradient functional materials based on the above-mentioned molding device, comprising the following steps: S1. Material preparation and storage: A variety of basalt fiber cement-based slurries with different functions are mixed and stirred by a mixer. Each functional slurry is injected into the corresponding sub-material mixing bin by a screw pump. At this time, the blocking device under each sub-material mixing bin is closed, and the sub-material mixing bin temporarily stores the slurry. S2. Independent mixing and online monitoring: The control system starts the first drive device to drive the sub-material mixing screw in each sub-material mixing chamber to independently mix the slurry; at the same time, each first material level monitoring module collects the radar echo signal on the surface of the slurry in the chamber in real time. By analyzing the stability and fluctuation amplitude of the echo signal, it is determined whether the slurry meets the preset printable process requirements. S3. First functional layer printing: The control system, based on the preset gradient structure model, starts the first drive device and sub-material mixing screw of the sub-material mixing chamber storing the first functional layer slurry, and opens the blocking device below the chamber to allow the slurry to flow into the main material extrusion chamber; the second drive device drives the main material mixing screw to perform secondary homogenization treatment on the flowing slurry; the treated slurry flows through the second material level monitoring module for final state verification, and after passing the test, it is extruded through the printing nozzle; the printing nozzle prints the first functional layer according to the preset printing path until the specified thickness is reached; after printing is completed, the blocking device of the chamber is closed and its sub-material mixing screw is stopped; S4. Empty the main material silo and empty the residual first functional layer slurry in the main material extrusion silo. S5. Printing of subsequent functional layers: Repeat steps S3 to S4, and start the mixing chamber containing the slurry of the second, third and so on of the functional layers in sequence, and print each functional layer in order until all functional layers are printed, forming a composite component with multi-layer gradient functions.

[0010] Preferably, the above method further includes a gradient transition step: when it is necessary to form a component gradient transition layer, the control system simultaneously opens the blocking devices of two adjacent sub-material mixing chambers and dynamically adjusts their openings respectively, so that the two different functional slurries are instantaneously mixed in the main material extrusion chamber and then extruded to form a component gradient transition zone with a thickness of 2~5mm.

[0011] Preferably, the printable process requirements are determined by the first material level monitoring module through analysis of the echo signal: when the fluctuation amplitude of the echo signal is continuously lower than the preset threshold, it is determined that the uniformity and rheological properties of the slurry meet the standards; if the slurry is found to be substandard, the control system automatically extends the stirring time, adjusts the stirring speed, or suspends the discharge and issues an audible and visual alarm.

[0012] Thirdly, the present invention provides a basalt fiber cement-based composite gradient functional material for use in the above-described molding method, wherein the concrete matrix is ​​prepared by a method comprising the following steps: (1) Add fine sand, sulfoaluminate cement, silica fume and fly ash into the mixer according to the mass ratio and dry mix for 30~120 seconds; (2) Add water and high-efficiency polycarboxylate superplasticizer, wet mix for 60~180 seconds to form cement mortar; (3) Add basalt fiber in batches, first stir at a low speed of 20~30r / min for 30~60 seconds, then stir at a high speed of 40~60r / min for 120~240 seconds to obtain concrete matrix; Furthermore, slag powder, ceramsite, diatomaceous earth, and perlite were added to the concrete matrix and mixed evenly to obtain four different types of concrete slurry with different functions.

[0013] Preferably, the specific surface area of ​​the sulfoaluminate cement is 350~450m².2 / kg, incoming temperature ≤50℃; fine sand application temperature ≤28℃; basalt fiber length 6~12mm, and surface modified; total amount of cementitious material not less than 400kg / m³ 3 The sulfoaluminate cement content is not less than 300 kg / m³. 3 The silica fume content is 5%~10%, the fly ash content is 10%~20%, and the water-cement ratio is not greater than 0.35.

[0014] Preferably, the volumetric content of basalt fiber in the four types of concrete slurry with different functions is distributed in a gradient: the volumetric content of slurry fiber used for the surface layer of the component is 0.5%~1.0%, the volumetric content of slurry fiber used for the transition layer is 1.0%~1.5%, and the volumetric content of slurry fiber used for the core layer or load-bearing layer is 1.5%~2.5%.

[0015] Therefore, the basalt fiber cement-based composite gradient functional material molding device and method of the present invention, which adopts the above-mentioned structure, has the following beneficial effects: (1) This invention uses four independent sub-material mixing chambers to discharge materials sequentially, allowing for the printing of load-bearing layers, sound-absorbing layers, thermal insulation layers, and decorative surfaces layer by layer within the same wall. The fiber volume content is distributed in a stepped gradient (load-bearing layer 1.5%~2.5%, sound-absorbing layer 0.5%~1.2%, thermal insulation layer 0.3%~0.8%, decorative layer 0.5%~1.0%), achieving a continuous and stable transition in performance, alleviating interfacial stress caused by differences in the performance of each layer, and preventing delamination or cracking. Under the same wall thickness, the comprehensive performance (strength, thermal insulation, sound insulation, energy absorption) is significantly better than that of traditional cast-in-place walls; it can even achieve better comprehensive performance while reducing the wall thickness, thereby saving building materials.

[0016] (2) This invention uses sulfoaluminate cement (which can be prepared from solid waste), combined with additive manufacturing technology to reduce material waste, and integrated molding to reduce construction energy consumption, which is in line with the green and low-carbon transformation and carbon emission reduction policy orientation.

[0017] (3) The first level of monitoring in this invention evaluates the mixing degree of the slurry in each compartment in real time, and the second level of monitoring performs a final check before extrusion to ensure that each layer of material is printed in the best rheological state, which greatly improves the interlayer bonding strength and printing quality stability.

[0018] (4) The material of the present invention organically integrates multiple functions such as anti-penetration, sound insulation, and heat insulation, which significantly improves the ability of the wall to resist external impact and damage, optimizes the thermal performance of the building envelope, and exhibits excellent durability in the high temperature, high humidity, and high salinity environment of remote islands and reefs, thus providing key technical support for the rapid construction and long-term use of offshore infrastructure.

[0019] (5) The number of sub-material mixing chambers of the present invention can be flexibly configured according to the actual number of functional areas (two, three or four) to meet the preparation needs of different gradient functional materials.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the molding device in an embodiment of the present invention; Figure 2 This is a schematic diagram of the slurry blocking device in an embodiment of the present invention; Figure 3 This is a schematic diagram of the sub-material mixing screw and sub-material mixing chamber in an embodiment of the present invention; Figure 4 This is a schematic diagram of a single sub-material mixing chamber in the non-working state in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the feeding state of a single sub-material mixing chamber in Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the mixing state of a single sub-material mixing chamber in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the discharge state of a single sub-material mixing chamber in Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the nozzle printing state in Embodiment 1 of the present invention; Figure 9 This is a schematic diagram of the four sub-material mixing chambers in the non-working state in Embodiment 2 of the present invention; Figure 10 This is a schematic diagram of the feeding status of the four sub-material mixing chambers in Embodiment 2 of the present invention; Figure 11 This is a schematic diagram of the discharge status of the four sub-material mixing chambers in Embodiment 2 of the present invention; Figure 12 This is a schematic diagram of the nozzle printing state in Embodiment 2 of the present invention; Figure 13 This is a flowchart illustrating the process of the molding apparatus of the present invention; Figure 14 This is a diagram illustrating the functional layer structure printed out according to the present invention; Figure 15 A schematic diagram showing the compressive strength of early functional graded concrete and traditional concrete; Figure 16 A comparison of the flexural strength of early functional graded concrete and traditional concrete; Figure Labels 1. 110 series two-phase hybrid stepper motor; 2. Control unit; 3. Feeding unit; 4. Printing nozzle; 5. Main material extrusion chamber; 6. Slurry blocker; 11. Agitator blades; 201. 86 series two-phase hybrid stepper motor I; 202. 86 series two-phase hybrid stepper motor II; 203. 86 series two-phase hybrid stepper motor III; 204. 86 series two-phase hybrid stepper motor IV; 301. Radar level gauge I; 302. Radar level gauge II; 303. Radar level gauge III; 304. Radar level gauge IV; 305. Radar level gauge V; 601. Blocking device I; 602. 603. Blocking device 2; 604. Blocking device 4; 701. Feed inlet 1; 702. Feed inlet 2; 703. Feed inlet 3; 704. Feed inlet 4; 801. Sub-material mixing bin 1; 802. Sub-material mixing bin 2; 803. Sub-material mixing bin 3; 804. Sub-material mixing bin 4; 901. Sub-material mixing screw 1; 902. Sub-material mixing screw 2; 903. Sub-material mixing screw 3; 904. Sub-material mixing screw 4; 905. Main material mixing screw; 1001. Discharge port 1; 1002. Discharge port 2; 1003. Discharge port 3; 1004. Discharge port 4. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] Example 1 This embodiment provides a method for fabricating a composite wall structure with load-bearing, functional (sound-absorbing / thermal-insulating), and surface decorative layers from bottom to top using the device of this invention, achieving the printing of multi-layered functional gradient components. The workflow of this embodiment is as follows: Figure 13 As shown.

[0025] 1. Overall structure of the device: Figure 1 The overall structure of the molding device is shown. For example... Figure 1 As shown, the device includes: a 110 series two-phase hybrid stepper motor 1 (second drive device) for driving the main material mixing screw 905; a control unit 2 for receiving sensor signals and sending control commands; a feeding unit 3 for replenishing slurry to each sub-material mixing chamber; a main material extrusion chamber 5 with a printing nozzle 4 at its bottom; the main material mixing screw 905 is located inside the main material extrusion chamber 5; and four sub-material mixing chambers (sub-material mixing chamber 1 801, sub-material mixing chamber 2 802, sub-material mixing chamber 3 803, and sub-material mixing chamber 4 804) are welded and fixed around or inside the main material extrusion chamber 5. Each sub-material mixing chamber is equipped with a radar level gauge (radar level gauge 1 301, radar level gauge 2 302, radar level gauge 3 303, and radar level gauge 4 304) on its top, which is the first level monitoring module. Each sub-material mixing chamber is equipped with an inlet (Inlet 1 701, Inlet 2 702, Inlet 3 703, Inlet 4 704) and an outlet (Outlet 1 1001, Outlet 2 1002, Outlet 3 1003, Outlet 4 1004). A radar level gauge 5 305 (second level monitoring module) is installed between the outlet of the main material extrusion chamber 5 and the printing nozzle 4 for final status verification.

[0026] Figure 2 The structure of the slurry blocker 6 is shown. Blocking device 1 601, blocking device 2 602, blocking device 3 603, and blocking device 4 604 are respectively installed at the discharge port of each sub-material mixing chamber to control the slurry outflow rate and can adjust the opening degree in real time.

[0027] Figure 3 The structure of the sub-material mixing screw and the sub-material mixing chamber is shown. Taking the sub-material mixing chamber 801 as an example, it contains a sub-material mixing screw 901, on which mixing blades 11 are mounted. The sub-material mixing screw 901 is driven by an 86 series two-phase hybrid stepper motor 201 (first drive device). The 86 series two-phase hybrid stepper motors 201, 202, 203, and 204 respectively drive the sub-material mixing screws 901, 902, 903, and 904.

[0028] 2. Material Preparation: The concrete matrix was prepared according to the method described in the third aspect. The parameters of the raw materials used are as follows: sulfoaluminate cement with a specific surface area of ​​350~450 m². 2 / kg, arrival temperature ≤50℃; fine sand application temperature ≤28℃; Class II fly ash water requirement ratio ≤80%, loss on ignition <4.3%; polycarboxylate superplasticizer water reduction rate ≥25%; basalt fiber length 6~12mm, surface modified. Sulfoaluminate cement can be prepared from industrial solid waste, realizing the resource utilization of waste.

[0029] The four functional materials are mixed separately using an agitator. Then, these four functional materials are injected into four sub-bins using a screw pump. Substrate mixing bin 1801: Load-bearing layer material (with added slag powder), fiber volume content 1.5%~2.5%, providing high-strength support; Substrate mixing chamber 2 802: Sound-absorbing layer material (with added ceramsite), fiber volume content 0.5%~1.2%, used to absorb impact energy or vibration energy; Substrate mixing bin 3 803: Insulation layer material (with added diatomaceous earth), fiber volume content 0.3%~0.8%, which serves as thermal insulation; Substrate mixing bin 4 804: Decorative surface material (with added perlite), fiber volume content 0.5%~1.0%, serving both decorative and surface protection functions.

[0030] The fiber volumetric content exhibits a stepped gradient distribution: it gradually decreases from the load-bearing layer (high content) to the sound-absorbing layer (medium-low content), the thermal insulation layer (low content), and then slightly increases towards the decorative surface layer (medium-low content). This stepped gradient design achieves a continuous and smooth transition of fiber content from the inside to the outside, effectively alleviating interfacial stress caused by differences in the properties of each layer (such as the coefficient of thermal expansion and the modulus of elasticity), preventing delamination or cracking, and improving the overall integrity of the material.

[0031] At this time, the blocking devices (blocking device 1 601, blocking device 2 602, blocking device 3 603, and blocking device 4 604) below each sub-bin are in the closed state, and the sub-bin temporarily serves as a storage device.

[0032] 3. System Self-Check and Material Replenishment: After the control system loads the preset printing task, it first performs a system self-check to confirm that each motor (1, 201-204), radar level gauge (301-305), slurry stopper (601-604), control unit 2, and feeding unit 3 are working normally. Subsequently, based on the feedback signals from radar level gauge 1 (301), radar level gauge 2 (302), radar level gauge 3 (303), and radar level gauge 4 (304), the slurry storage in each bin is determined. If the material level is lower than the preset lower limit, the control system automatically starts feeding unit 3, replenishing material to the corresponding bin through flexible hoses via inlet 1 (701), flexible hose via inlet 2 (702), flexible hose via inlet 3 (703), and flexible hose via inlet 4 (704) until the radar level gauges indicate that the material level has reached the preset upper limit.

[0033] 4. Independent mixing and online monitoring: Figure 4 The image shows the sub-material mixing bin 801 in a non-working state, where there is no material in the bin or the motor is not running.

[0034] Figure 5 The image shows the feeding status of the feed mixing bin 801, with the slurry entering the bin through feed inlet 701. GGBS is granulated blast furnace slag powder.

[0035] After feeding is completed, the control system starts the 86 series two-phase hybrid stepper motor-201 (first drive device), which drives the sub-material mixing screw-901 and its mixing blades 11 to independently mix the slurry in the bin. Figure 6 As shown. During the mixing process, the radar level gauge 301 (first level monitoring module) above the silo works continuously. Its monitoring principle is as follows: it emits high-frequency electromagnetic pulses to the slurry surface, receives the reflected echoes, and evaluates the uniformity and rheology of the slurry by analyzing the stability and fluctuation amplitude of the echo signals. When the amplitude of the echo signal fluctuations is continuously lower than the preset threshold, it is determined that the mixing is complete, and the motor switches to low speed to maintain operation. The mixing process of the sub-material mixing silos two, three, and four is the same, and the corresponding screws are driven by the 86 series two-phase hybrid stepper motor 202, 86 series two-phase hybrid stepper motor 203, and 86 series two-phase hybrid stepper motor 404, respectively, and are monitored by radar level gauges 302, 303, and 4, respectively.

[0036] 5. Gradient printing: (1) Print the first functional area - load-bearing layer: such as Figure 7 As shown, the control system starts the sub-material mixing screw 901 (maintaining mixing state) in the sub-material mixing chamber 801, which stores the load-bearing layer material, and opens the blocking device 601 below it. The load-bearing layer material is extruded into the main material extrusion chamber 5. The main material mixing screw 905 in the main material extrusion chamber 5 is driven by a 110 series two-phase hybrid stepper motor 1 (second drive device) and is always in the running state. Figure 8 As shown, after secondary homogenization by the main material mixing screw 905, the material flows through radar level gauge 305 (second level monitoring module) for final state verification. Once qualified, it is extruded from the printing nozzle 4. The entire printing head prints the first functional layer according to the preset printing path. Depending on the needs, 3-4 layers of slurry can be printed continuously, each with uniform thickness. When the specified thickness is reached, the blocking device 601 is closed, and the sub-material mixing screw 901 is stopped. The first functional layer printing is now complete. Before printing the next layer, the remaining load-bearing layer material in the main material extrusion chamber 5 is emptied.

[0037] (2) Printing the second functional area - sound-absorbing layer: After emptying the remaining load-bearing layer material in the main material extrusion chamber 5, the control system starts the sub-material mixing screw 902 of the sub-material mixing chamber 802 containing the sound-absorbing layer material, and opens the blocking device 602. The sound-absorbing material is extruded into the main material extrusion chamber 5, and after secondary homogenization and verification, it is extruded by the printing nozzle 4. The printing nozzle prints the second functional layer according to the preset printing path, printing 3-4 layers of slurry to the specified thickness and then stopping. The blocking device 602 is closed, and the sub-material mixing screw 902 is stopped. The remaining sound-absorbing material in the main material extrusion chamber 5 is emptied.

[0038] (3) Printing the third functional area - insulation layer: After emptying the main material extrusion chamber 5, the control system starts the sub-material mixing screw 903 of the sub-material mixing chamber 803 containing the insulation layer material, and opens the blocking device 603. The insulation material is extruded into the main material extrusion chamber 5, and after secondary homogenization and verification, it is extruded and printed. The printing nozzle prints the third functional layer according to the preset printing path, printing 3-4 layers of slurry to the specified thickness and then stopping. Close the blocking device 603 and stop the sub-material mixing screw 903. Empty the remaining insulation material in the main material extrusion chamber 5.

[0039] (4) Printing the fourth functional area - decorative surface layer: After emptying the main material extrusion chamber 5, the control system starts the sub-material mixing screw 904 of the sub-material mixing chamber 804 which stores the surface layer material, and opens the blocking device 604. The surface layer material is extruded into the main material extrusion chamber 5, and after secondary homogenization and verification, it is extruded and printed. The printing nozzle prints the fourth functional layer according to the preset printing path, and stops after printing to the specified thickness. The blocking device 604 is closed, and the sub-material mixing screw 904 is stopped.

[0040] (5) Gradient transition layer: When it is necessary to form a component gradual transition zone between adjacent functional layers, the blocking devices of the current chamber and the next chamber can be opened at the moment of switching chambers, and the opening degree can be dynamically adjusted so that the two slurries are instantly mixed in the main material extrusion chamber and then extruded to form a 2~5mm transition layer, which further eliminates the stress concentration at the interface.

[0041] Throughout the printing process, the interlayer interval is ≤15 minutes, the printing environment temperature is 25℃, the relative humidity is 60%, and the extrusion slurry temperature is ≤30℃. The printed functional layer structure is as follows: Figure 14 As shown 6. Curing: Immediately after printing, cover with plastic film and let stand for 3 hours until final set. Then, perform standard curing (temperature 20±2℃, humidity ≥95%) for no less than 14 days.

[0042] Example 2 1. Equipment status and material loading: Figure 9The four sub-material mixing chambers (sub-material mixing chamber 1 801, sub-material mixing chamber 2 802, sub-material mixing chamber 3 803, and sub-material mixing chamber 4 804) are shown in a non-working state. At this time, there is no mixing action in each chamber, and each blocking device is in the closed state.

[0043] Figure 10 The feeding status of four sub-material mixing bins is shown. Four functional slurries enter the corresponding bins through inlet 1 (701), inlet 2 (702), inlet 3 (703), and inlet 4 (704), respectively. The slurry ratio in each bin is the same as in Example 1, namely: sub-material mixing bin 1 (801) is loaded with load-bearing layer material (with added slag powder and fiber volume content of 1.5%~2.5%), sub-material mixing bin 2 (802) is loaded with sound-absorbing layer material (with added ceramsite and fiber volume content of 0.5%~1.2%), sub-material mixing bin 3 (803) is loaded with thermal insulation layer material (with added diatomaceous earth and fiber volume content of 0.3%~0.8%), and sub-material mixing bin 4 (804) is loaded with decorative surface material (with added perlite and fiber volume content of 0.5%~1.0%).

[0044] 2. Simultaneous mixing and discharging: The control system activates 86-series two-phase hybrid stepper motors 201, 202, 203, and 204 (first drive device) to drive sub-material mixing screws 901, 902, 903, and 904 to independently mix the slurry in each bin. Radar level gauges 301, 302, 303, and 304 (first level monitoring module) above each bin monitor the mixing progress, using the same detection principle as in Example 1. When the slurry in each bin reaches a printable state, the control system simultaneously activates four blocking devices (blocking device 601, blocking device 602, blocking device 603, and blocking device 604). Figure 11 As shown, four types of slurry, in a preset equal volume ratio, simultaneously flow into the main material extrusion silo 5 through outlet 1001, outlet 2 1002, outlet 3 1003, and outlet 4 1004. Among them, PFA is fly ash, Sand is sand, and OPC is ordinary Portland cement.

[0045] 3. Centralized mixing and printing: like Figure 12 As shown, the main material mixing screw 905 performs high-intensity mixing of the four slurries to ensure macroscopic uniformity. The mixed slurry flows through the verification radar level gauge 305 (second level monitoring module), and after the uniformity is qualified, it is extruded and formed by the printing nozzle 4. The subsequent curing steps are the same as in Example 1.

[0046] Comparative Example and Effect Verification: A standard concrete wall of the same thickness was prepared using a traditional manual mixing, layering, and vibration molding method as a comparative example. Tests showed: The gradient functional wall prepared in Example 1, with the same thickness, has an impact resistance (energy absorption) improved by about 50%, a sound insulation effect improved by about 30%, a thermal insulation performance improved by about 40%, and a load-bearing strength no less than that of traditional walls; Due to the adoption of a stepped fiber content gradient design, the interfacial stress between layers is effectively relieved. No delamination cracking occurred after 30 freeze-thaw cycles, while the comparative wall cracked after 12 cycles. Under the premise of achieving the same overall performance, the thickness of the wall in Example 1 can be reduced by 20% to 30%, saving about 25% of concrete materials and significantly reducing the generation of construction waste.

[0047] Figure 15 and Figure 16 This chart compares the compressive and flexural strengths of early-stage (1-day) functionally graded concrete with conventional concrete. The cementitious material is sulfoaluminate cement, the fiber is basalt fiber, the mineral admixtures are silica fume, fly ash, and fine sand, and the admixture is high-efficiency polycarboxylate superplasticizer. H1 represents a conventional concrete embossed component without basalt fiber, and H2 represents a functionally graded embossed component, where the first layer (bottom layer) is the load-bearing layer, the second layer is the insulation layer, the third layer is the sound-absorbing layer, and the fourth layer (top layer) is the surface layer. Both H1 and H2 have a thickness of 100mm. Figure 15 and Figure 16 It can be observed that group H2 has the best mechanical properties, with a flexural strength of 6.5 MPa and a compressive strength of 8.2 MPa.

[0048] The basalt fiber cement-based composite gradient functional material prepared by the device and method of this invention can be applied to the construction of critical infrastructure walls in harsh marine environments such as offshore islands and reefs, including offshore integrated supply bases, outposts, and command centers. Through a stepped gradient design of material components and structure, it achieves integrated functions such as "protection against penetration," "sound insulation," and "thermal insulation," significantly improving the wall's ability to withstand external impacts and shocks, optimizing building thermal performance, and enhancing the durability of offshore islands and reefs in high-temperature, high-humidity, and high-salt environments. This provides crucial technical support for the rapid and efficient construction of offshore engineering projects.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A molding device for basalt fiber cement-based composite gradient functional materials, characterized in that, include: The main material extrusion chamber is equipped with a main material mixing screw inside, and a printing nozzle is connected to its bottom; At least two sub-material mixing chambers are fixedly installed above the main material extrusion chamber. Each sub-material mixing chamber has an independent inlet, outlet, and sub-material mixing screw. The outlet is connected to the main material extrusion chamber through a flow controllable blocking device. The first driving device is used to drive the sub-material mixing screw to rotate; The second drive unit is used to drive the main material mixing screw to rotate. The first material level monitoring module is installed at the top of each sub-material mixing bin to monitor the material level height and mixing status of the slurry in the bin in real time. The mixing status includes the uniformity and rheology of the slurry. The second material level monitoring module is located in the channel between the discharge port of the main material extrusion chamber and the printing nozzle, and is used to perform a final state check on the slurry that is about to enter the printing nozzle. The control system is electrically connected to the blocking device, the first driving device, the second driving device, the first material level monitoring module, and the second material level monitoring module, respectively. The control system is configured to: execute a preset printing task, control the mixing process of each sub-material mixing chamber according to the feedback signal of the first material level monitoring module, open each blocking device in sequence or proportion according to the preset gradient structure model, and decide whether to allow extrusion printing according to the verification result of the second material level monitoring module.

2. The molding apparatus according to claim 1, characterized in that, There are four sub-material mixing chambers, and the four sub-material mixing chambers are welded and fixed inside or around the main material extrusion chamber; the sub-material mixing screw and the main material mixing screw are interchangeable.

3. The molding apparatus according to claim 1, characterized in that, Both the first and second level monitoring modules are radar level gauges. They determine the uniformity and rheological state of the slurry by emitting high-frequency electromagnetic waves to the slurry surface and analyzing the signal stability and fluctuation amplitude of the reflected echo.

4. A method for molding basalt fiber cement-based composite gradient functional materials based on the molding apparatus described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Material preparation and storage: A variety of basalt fiber cement-based slurries with different functions are mixed and stirred by a mixer. Each functional slurry is injected into the corresponding sub-material mixing bin by a screw pump. At this time, the blocking device under each sub-material mixing bin is closed, and the sub-material mixing bin temporarily stores the slurry. S2. Independent mixing and online monitoring: The control system starts the first drive device to drive the sub-material mixing screw in each sub-material mixing chamber to independently mix the slurry; at the same time, each first material level monitoring module collects the radar echo signal on the surface of the slurry in the chamber in real time. By analyzing the stability and fluctuation amplitude of the echo signal, it is determined whether the slurry meets the preset printable process requirements. S3. First functional layer printing: The control system starts the first drive device and the sub-material mixing screw of the sub-material mixing chamber storing the first functional layer slurry according to the preset gradient structure model, and opens the blocking device below the chamber to allow the slurry to flow into the main material extrusion chamber. The second drive unit drives the main material mixing screw to perform secondary homogenization treatment on the incoming slurry; The processed slurry flows through the second material level monitoring module for final status verification. After passing the test, it is extruded through the printing nozzle. The printing nozzle prints the first functional layer according to the preset printing path until the specified thickness is reached. After printing is complete, close the blocking device of the chamber and stop its sub-material mixing screw; S4. Empty the main material silo and empty the residual first functional layer slurry in the main material extrusion silo. S5. Printing of subsequent functional layers: Repeat steps S3 to S4, and start the mixing chamber containing the slurry of the second, third and so on of the functional layers in sequence, and print each functional layer in order until all functional layers are printed, forming a composite component with multi-layer gradient functions.

5. The molding method according to claim 4, characterized in that, It also includes a gradient transition step: when it is necessary to form a component gradient transition layer, the control system simultaneously opens the blocking devices of two adjacent sub-material mixing chambers and dynamically adjusts their openings respectively, so that the two different functional slurries are instantly mixed in the main material extrusion chamber and then extruded to form a component gradient transition zone with a thickness of 2~5mm.

6. The molding method according to claim 4, characterized in that, The printable process requirements are determined by the first material level monitoring module through analysis of the echo signal: when the fluctuation amplitude of the echo signal is continuously lower than the preset threshold, it is determined that the uniformity and rheological properties of the slurry meet the standards; if the slurry is detected to be substandard, the control system automatically extends the stirring time, adjusts the stirring speed, or suspends the discharge and issues an audible and visual alarm.

7. The molding method according to claim 4, characterized in that, The process parameters during printing are as follows: printing ambient temperature 5~35℃, relative humidity ≤80%; printing nozzle extrusion slurry temperature ≤30℃; interlayer interval time controlled before the initial setting of cement-based materials, not exceeding 15 minutes; the printed components are immediately covered for curing, with a curing time of not less than 14 days and a curing temperature of 20±2℃.

8. The molding method according to claim 4, characterized in that, The basalt fiber cement-based composite gradient functional material produced by the molding method has a concrete matrix prepared by a method comprising the following steps: (1) Add fine sand, sulfoaluminate cement, silica fume and fly ash into the mixer according to the mass ratio and dry mix for 30~120 seconds; (2) Add water and high-efficiency polycarboxylate superplasticizer, wet mix for 60~180 seconds to form cement mortar; (3) Add basalt fiber in batches, first stir at a low speed of 20~30r / min for 30~60 seconds, then stir at a high speed of 40~60r / min for 120~240 seconds to obtain concrete matrix; Furthermore, slag powder, ceramsite, diatomaceous earth, and perlite were added to the concrete matrix and mixed evenly to obtain four different types of concrete slurry with different functions.

9. The molding method according to claim 8, characterized in that, The specific surface area of ​​sulfoaluminate cement is 350~450m². 2 / kg, incoming temperature ≤50℃; fine sand application temperature ≤28℃; basalt fiber length 6~12mm, and surface modified; total amount of cementitious material not less than 400kg / m³ 3 The sulfoaluminate cement content is not less than 300 kg / m³. 3 The silica fume content is 5%~10%, the fly ash content is 10%~20%, and the water-cement ratio is not greater than 0.

35.

10. The molding method according to claim 8, characterized in that, Among the four types of concrete slurry with different functions, the volumetric content of basalt fiber is distributed in a gradient: the volumetric content of slurry fiber used for the surface layer of the component is 0.5%~1.0%, the volumetric content of slurry fiber used for the transition layer is 1.0%~1.5%, and the volumetric content of slurry fiber used for the core layer or load-bearing layer is 1.5%~2.5%.

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