Preparation method of perforated UHPC board fireproof, high-temperature-resistant, waterproof and moisture-proof strong sound absorption composite material

Abstract

The invention provides a preparation method of a perforated UHPC board fireproof, high-temperature-resistant, waterproof and moisture-proof strong sound absorption composite material, and belongs to the technical field of UHPC boards. An optimal perforation parameter combination is calculated through a two-layer nested optimization function system; preparing UHPC slurry and adding polypropylene fibers for toughening; carrying out pouring molding by adopting a vacuum vibration process and carrying out steam curing; performing precise perforation according to the optimized parameters; the basalt fiber cloth is adhered to the back surface to enhance the low and medium frequency sound absorption performance; the surface is coated with nano silicon dioxide sol to form a waterproof and moistureproof protection layer; performing acoustic performance evaluation to ensure that the medium-frequency sound absorption coefficient is greater than or equal to 0.7 and the high frequency is greater than or A fireproof performance test is carried out to ensure that an A-grade fireproof grade and a 2-hour fire endurance are reached; finally, performing a waterproof and moisture-proof performance test to ensure the water absorption rate lt; and 50 times of damp-heat circulation can be resisted. The optimal parameters comprise common perforation UHPC: the hole diameter is 5mm, the distance between the circle centers of two holes is 12mm, and the perforation rate is 13%; the method realizes organic unification of sound absorption performance and special environment adaptability.

Description

Technical Field

[0001] The present invention belongs to the technical field of UHPC boards, and specifically relates to a preparation method of a strong sound-absorbing composite material with fire resistance, high temperature resistance, waterproof and moisture-proof properties for a perforated UHPC board. Background Art

[0002] Sound-absorbing materials are widely used in the field of noise control in places such as architectural acoustics, subway stations, and tunnels. Traditional sound-absorbing materials mainly include porous materials, fiber materials, and micro-perforated plates. These materials convert sound energy into heat energy through the pore structure or perforated structure inside the material, thereby achieving sound absorption and noise reduction. However, traditional sound-absorbing materials such as fiber materials like mineral wool and glass wool have good medium and high-frequency sound absorption performance, but are prone to mildew and degradation in a humid environment and have poor fire resistance, unable to meet the usage requirements of special environments.

[0003] Currently, the micro-perforated plate sound-absorbing structure has attracted much attention due to its good sound absorption performance and environmental protection characteristics. However, traditional metal or plastic micro-perforated plates are prone to deformation and melting in a high-temperature environment and have insufficient fire resistance. Although cement-based micro-perforated plates have certain fire resistance, ordinary concrete has low strength and is prone to cracking, making it difficult to maintain an accurate perforated structure, and it is difficult to balance sound absorption performance with waterproof and moisture-proof performance, resulting in rapid deterioration of performance in high-humidity, high-temperature, and fire environments.

[0004] Therefore, how to develop a composite material that simultaneously has high-efficiency sound absorption performance, fire resistance, high temperature resistance, waterproof and moisture-proof performance, and realizes multi-functional integration has become an urgent technical problem to be solved. Existing technologies are difficult to meet these seemingly contradictory performance requirements through a single material or a simple combination, lacking systematic optimization design methods and preparation processes, and unable to achieve the overall balance and coordinated improvement of performance. That is to say, there are technical problems in the existing technology that it is difficult to balance multiple functional requirements such as high-efficiency sound absorption performance with fire resistance, high temperature resistance, waterproof and moisture-proof properties. Summary of the Invention

[0005] In view of this, the present invention provides a preparation method of a strong sound-absorbing composite material with fire resistance, high temperature resistance, waterproof and moisture-proof properties for a perforated UHPC board, which can solve the technical problems in the existing technology that it is difficult to balance multiple functional requirements such as high-efficiency sound absorption performance with fire resistance, high temperature resistance, waterproof and moisture-proof properties.

[0006] The present invention is implemented as follows: The present invention provides a preparation method of a strong sound-absorbing composite material with fire resistance, high temperature resistance, waterproofness and moisture resistance for a perforated UHPC board, which includes the following operating steps: calculating the preferred parameter vector of the perforated UHPC board by using a two-layer nested optimization function system to obtain the optimal parameter combination; preparing the UHPC slurry and performing toughening treatment; pouring the slurry into a mold and curing; performing precise perforation treatment on the cured UHPC board according to the optimal parameter combination; bonding and fixing a basalt fiber cloth or a glass fiber board on the back of the perforated UHPC board; coating nano-silica sol on the surface of the perforated UHPC board to form a waterproof and moisture-proof protective layer; predicting and testing the acoustic performance of the composite material by using an acoustic performance evaluation function; performing fire resistance testing and waterproof and moisture-proof performance testing on the composite material to obtain the final material.

[0007] Among them, when calculating the preferred parameter vector of the perforated UHPC board by using a two-layer nested optimization function system, the best acoustic parameter combination and the best structural parameter combination are respectively output through an acoustic parameter optimization function and a structural parameter optimization function, and then the optimal parameter combination including the perforation diameter, the center distance between adjacent hole centers, the perforation rate, the regular hexagon close-packed array arrangement and the UHPC board thickness is output by a combination optimization function.

[0008] Among them, specifically for preparing the UHPC slurry, by mass fraction, 100 parts of cement, 25 parts of silica fume, 120 parts of quartz sand, 2 parts of water reducer, 32 parts of water are mixed evenly, and then polypropylene fibers with a volume fraction of 2% are added for toughening treatment.

[0009] Among them, specifically for pouring the slurry into a mold and curing, the prepared UHPC slurry is poured into a mold, and the vacuum vibration process is used to discharge air bubbles. After initial setting for 4 to 6 hours under standard curing conditions, steam curing is carried out at 60°C to 90°C for 24 to 48 hours.

[0010] Among them, specifically for performing precise perforation treatment on the cured UHPC board according to the optimal parameter combination, a numerical control drilling device is used for processing to ensure that the error of the perforation diameter is controlled within ±0.2 mm, and the error of the center distance between adjacent hole centers is controlled within ±0.5 mm.

[0011] Among them, specifically for bonding and fixing the basalt fiber cloth or the glass fiber board on the back of the perforated UHPC board, the basalt fiber cloth or the glass fiber board is cut into a shape with the same size as the perforated UHPC board, and an epoxy resin adhesive is used for bonding and fixing on the back of the perforated UHPC board, and the curing time is 24 to 36 hours.

[0012] Among them, the drying and curing time of coating nano-silica sol on the surface of the perforated UHPC board is 12 to 24 hours, and the coating thickness is controlled within 0.5 to 1.0 mm.

[0013] Among them, the specific process of predicting and testing the acoustic performance of the composite material using the acoustic performance evaluation function is as follows: the acoustic performance evaluation function inputs the perforation aperture, center distance between adjacent hole centers, perforation rate, regular hexagon close-packed array arrangement, and UHPC plate thickness determined by the acoustic parameter optimization function and the structural parameter optimization function, and measures the sound absorption coefficient using the impedance tube method in the frequency range of 125 Hz to 4000 Hz, ensuring that the sound absorption coefficient in the mid-frequency band is not less than 0.7 and the sound absorption coefficient in the high-frequency band is not less than 0.9.

[0014] Among them, the two-layer nested optimization function system refers to a calculation system that includes the first-layer optimization and the second-layer optimization. The first-layer optimization includes the acoustic parameter optimization function and the structural parameter optimization function, and the second layer is the combined optimization function that constructs a parameter space within the range of the first-layer results for overall performance balance.

[0015] Among them, the acoustic parameter optimization function is used to solve the best matching relationship between perforation parameters. The inputs include the target frequency range, expected sound absorption coefficient, perforation parameter constraint conditions, and material acoustic impedance characteristics, and the output is the best combination plan of the perforation aperture, center distance between adjacent hole centers, and perforation rate that meets the acoustic performance requirements; the structural parameter optimization function is used to determine the best matching relationship between the perforation arrangement and the UHPC plate thickness. The inputs include the load condition, span requirement, deformation limit, and perforation rate, and the output is the combination plan of the regular hexagon close-packed array arrangement and the UHPC plate thickness that meets the structural strength and stiffness requirements; the combined optimization function is used to perform overall performance balance based on the results of the two groups of optimizations in the first layer. The inputs include the result set of the acoustic parameter optimization function, the result set of the structural parameter optimization function, manufacturing process constraints, and cost factors, and the output is the optimal parameter combination that comprehensively considers acoustic performance, structural performance, manufacturing feasibility, and cost-effectiveness.

[0016] Compared with the prior art, the present invention provides a preparation method for a highly sound-absorbing composite material of a perforated UHPC plate with fire resistance, high temperature resistance, water resistance, and moisture resistance. The present invention proposes a preparation method for a highly sound-absorbing composite material of a perforated UHPC plate with fire resistance, high temperature resistance, water resistance, and moisture resistance. By calculating the perforation parameters through a two-layer nested optimization function system, combining the characteristics of UHPC materials and precise perforation processes, and using basalt fiber cloth backing and nano-coating surface treatment, the organic unity of sound absorption performance and special environment adaptability is achieved.

[0017] This preparation method solves the problem of unstable performance of traditional sound-absorbing materials in special environments. The prepared composite material has a sound absorption coefficient of not less than 0.7 in the mid-frequency band and not less than 0.9 in the high-frequency band, and at the same time has an A-level fire rating, a fire resistance limit of not less than 2 hours, a water absorption rate of less than 3%, and can maintain stable performance after 50 wet and hot cycles. This multi-functional integrated design overcomes the contradiction that it is difficult to balance sound absorption performance and environmental adaptability in traditional technologies.

[0018] Through optimized design and precise preparation, the present invention has successfully solved the technical problem in the prior art that it is difficult to balance the requirements of high-efficiency sound absorption performance and multiple functions such as fire resistance, high temperature resistance, waterproofing, and moisture resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flowchart of the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0021] As Figure 1 shown, it is a flowchart of a preparation method of a perforated UHPC board with strong sound absorption composite material for fire resistance, high temperature resistance, waterproofing, and moisture resistance provided by the present invention. The method includes the following steps:

[0022] S01. Calculate the preferred parameter vector of the perforated UHPC board by using a two-layer nested optimization function system. Output the best acoustic parameter combination and the best structural parameter combination through the acoustic parameter optimization function and the structural parameter optimization function respectively, and then output the optimal parameter combination including the perforation diameter, the center distance between adjacent hole centers, the perforation rate, the regular hexagon close-packed array arrangement, and the UHPC board thickness by the combination optimization function;

[0023] S02. Prepare the UHPC slurry. By mass, 100 parts of cement, 25 parts of silica fume, 120 parts of quartz sand, 2 parts of water reducer, 32 parts of water. After mixing evenly, add polypropylene fiber with a volume fraction of 2% for toughening treatment;

[0024] S03. Pour the prepared UHPC slurry into the mold, use the vacuum vibration process to discharge air bubbles. After initial setting for 4 to 6 hours under standard curing conditions, carry out steam curing at 60°C to 90°C for 24 to 48 hours;

[0025] S04. Carry out precise perforation treatment on the cured UHPC board according to the optimal parameter combination, and use numerical control drilling equipment for processing to ensure that the error of the perforation diameter is controlled within ±0.2 mm, and the error of the center distance between adjacent hole centers is controlled within ±0.5 mm;

[0026] S05. Cut the basalt fiber cloth or fiberglass board into the same shape as the perforated UHPC board, and use epoxy resin adhesive to bond and fix it on the back of the perforated UHPC board. The curing time is 24 to 36 hours;

[0027] S06. Coat the surface of the perforated UHPC board with nano-silica sol to form a waterproof and moisture-proof protective layer. The drying and curing time is 12 to 24 hours, and the coating thickness is controlled within 0.5 to 1.0 mm.

[0028] S07. Apply an acoustic performance evaluation function to predict and test the acoustic performance of the prepared composite material. The acoustic performance evaluation function inputs the perforation diameter, center distance between adjacent hole centers, perforation rate, regular hexagon close-packed array arrangement, and UHPC board thickness determined by the acoustic parameter optimization function and the structural parameter optimization function. Use the impedance tube method to measure the sound absorption coefficient in the frequency range of 125 Hz to 4000 Hz, ensuring that the sound absorption coefficient in the mid-frequency band is not less than 0.7 and that in the high-frequency band is not less than 0.9.

[0029] S08. Conduct a fire resistance test on the composite material. Conduct a combustion performance classification test according to national standards to ensure that the composite material reaches Class A fire resistance rating and the fire resistance limit is not less than 2 hours.

[0030] S09. Conduct a waterproof and moisture-proof performance test on the composite material. Conduct a water absorption test and a damp-heat environment cycle test according to national standards to ensure that the water absorption rate is less than 3%, and the performance degradation does not exceed 5% after 50 damp-heat cycles.

[0031] Among them, the two-layer nested optimization function system refers to a calculation system including the first-layer optimization and the second-layer optimization. The first-layer optimization includes the acoustic parameter optimization function and the structural parameter optimization function. The second layer is the combined optimization function that constructs a parameter space within the range of the first-layer results for overall performance balance.

[0032] Among them, UHPC refers to a new type of cement-based composite material with a strength grade not less than 150 MPa, featuring ultra-high strength, ultra-high toughness, and ultra-high durability.

[0033] Among them, polypropylene fiber refers to a synthetic fiber made by melt spinning of polypropylene resin, which is used to enhance the crack resistance and toughness of UHPC boards.

[0034] Among them, basalt fiber cloth refers to an inorganic fiber fabric made by high-temperature melting and drawing of basalt magma, which has excellent sound insulation and sound absorption performance and high-temperature resistance.

[0035] Among them, the regular hexagon close-packed array arrangement means that the perforations are evenly distributed according to a regular hexagon grid, which is conducive to the uniform diffusion and absorption of sound waves inside the material, and at the same time improves the structural strength of the material.

[0036] Among them, nano-silica sol refers to a stable dispersion system formed by silica particles with a particle size less than 100 nm in a liquid, which has excellent waterproof and moisture-proof performance.

[0037] Among them, the impedance tube method refers to a test method that utilizes the characteristics of sound wave propagation in a pipeline to determine the acoustic properties of materials by measuring sound pressure and particle vibration velocity.

[0038] Among them, the acoustic parameter optimization function is used to solve the optimal matching relationship between perforation parameters. The inputs include the target frequency range, expected sound absorption coefficient, perforation parameter constraints, and material acoustic impedance characteristics. The output is the optimal combination scheme of the perforation aperture, center-to-center distance between adjacent holes, and perforation rate that meets the acoustic performance requirements.

[0039] Among them, the structural parameter optimization function is used to determine the optimal matching relationship between the perforation arrangement pattern and the thickness of the UHPC plate. The inputs include the load conditions, span requirements, deformation limits, and perforation rate. The output is the combination scheme of the regular hexagonal close-packed array arrangement and the UHPC plate thickness that meets the requirements of structural strength and stiffness.

[0040] Among them, the combined optimization function is used to balance the overall performance based on the optimization results of two groups in the first layer. The inputs include the result set of the acoustic parameter optimization function, the result set of the structural parameter optimization function, manufacturing process constraints, and cost factors. The output is the optimal parameter combination that comprehensively considers acoustic performance, structural performance, manufacturing feasibility, and cost-effectiveness.

[0041] Among them, the acoustic performance evaluation function is used to predict the acoustic performance of the perforated UHPC plate composite material. The inputs include the perforation aperture, perforation rate, UHPC plate thickness, type of basalt fiber cloth or glass fiber board, and thickness of basalt fiber cloth or glass fiber board. The output is the theoretical sound absorption coefficient curve and comprehensive score value in different frequency bands.

[0042] The following is a detailed description of the specific implementation manners of the above steps.

[0043] The specific implementation manner of step S01 is to establish a two-layer nested optimization function system for optimizing the parameters of the perforated UHPC plate. First, an acoustic parameter optimization function is constructed. This function is based on the Delft - Eindhoven model to establish a mathematical expression of the sound absorption mechanism of the perforated plate. Taking the perforation aperture, center-to-center distance between adjacent holes, and perforation rate as input variables, and the target sound absorption coefficient curve in the frequency band from 125 Hz to 4000 Hz as the optimization target, a mapping relationship between parameters and performance is constructed by the multi-response surface method, and the gradient descent algorithm is used to solve the optimal acoustic parameter combination. This combination needs to ensure that the sound absorption coefficient in the mid-frequency band (500 Hz to 2000 Hz) is not less than 0.7, and the sound absorption coefficient in the high-frequency band (2000 Hz to 4000 Hz) is not less than 0.9; then a structural parameter optimization function is constructed. This function is based on the meso-mechanics model and finite element analysis. Taking the regular hexagonal close-packed array arrangement parameters and the UHPC plate thickness as input variables, and the flexural strength not less than 30 MPa and the impact toughness not less than 2000 J / m 2Set it as a constraint condition and solve the optimal combination of structural parameters by the Lagrange multiplier method; finally, construct a combined optimization function. This function takes the result sets of acoustic parameter optimization and structural parameter optimization as the initial solution space, introduces manufacturing process constraints (such as hole diameter accuracy of ±0.2 mm and hole pitch accuracy of ±0.5 mm) and cost factors (the weighted sum of raw material cost, processing cost, and time cost), and uses an adaptive genetic algorithm for global search. The optimization objective function is the weighted sum of the acoustic performance score (weight 0.5), the structural performance score (weight 0.3), and the economic performance score (weight 0.2), and the parameter vector is output through 500 generations of iterative calculations. The purpose of this step is to ensure that the design parameters meet the requirements of both acoustic performance and structural performance, and balance manufacturing feasibility and economy.

[0044] The specific implementation of step S02 is to prepare UHPC slurry. First, conduct quality inspections on the raw materials. Select Portland cement with a strength grade not lower than 52.5, silica fume with a specific surface area not lower than 28,000 m² / kg, quartz sand with a particle size distribution ranging from 0.1 mm to 0.6 mm, and polycarboxylate superplasticizer with a water reduction rate not lower than 25% to ensure that the raw materials meet the requirements for UHPC preparation; then mix the cement and silica fume evenly, and use a high-speed mixer to stir at a speed of 2000 revolutions per minute for 3 minutes to ensure that the silica fume particles are evenly dispersed among the cement particles; then add the quartz sand and continue to stir for 2 minutes to make the quartz sand evenly distributed; then dissolve the superplasticizer in water and slowly add it to the dry mixture, and use a low-speed mixer at 400 revolutions per minute to stir for 5 minutes, and then stir at a medium speed of 800 revolutions per minute for 3 minutes to make the mixture fully wetted and form a slurry with good fluidity; finally, add polypropylene fibers with a length of 12 mm and a diameter of 0.2 mm, with a volume fraction of 2%, and continue to stir for 2 minutes to make the fibers evenly dispersed in the slurry. The purpose of this step is to prepare UHPC slurry with excellent mechanical properties and good fluidity. The addition of fibers improves the crack resistance and toughness of the material and reduces the risk of shrinkage cracking.

[0045] The specific implementation of step S03 is to cast and cure the UHPC board. First, prepare a steel mold with dimensions of 600 mm × 600 mm × the required thickness. Coat the inner wall of the mold with a release agent to ensure smooth demolding. Then, slowly pour the prepared UHPC slurry into the mold, vibrate it on a vibrating table at a frequency of 50 Hz for 30 seconds, and then apply a vacuum negative pressure of 0.08 MPa for 10 minutes to fully discharge the air bubbles in the slurry. Next, move the mold to a constant temperature and humidity curing chamber for standard curing. Control the temperature at 20 ± 2 °C, the relative humidity not less than 95%, and the curing time is 4 to 6 hours until the concrete reaches the initial setting state. Then, transfer the mold to a steam curing chamber, gradually heat it up to 85 °C at a heating rate of 10 °C / hour, keep it warm for 24 hours, and then cool it down to room temperature at a rate of 5 °C / hour. Finally, perform demolding treatment and continue to cure it under standard conditions for 7 days. The purpose of this step is to ensure that the UHPC is fully hydrated and hardened to form a dense microstructure. The vacuum vibration process effectively reduces pore defects and improves the material density. Steam curing promotes the formation of C-S-H gel, significantly improving the early strength and durability of the material.

[0046] The specific implementation of step S04 is to perform precision perforation treatment. First, according to the perforation parameters calculated by the optimization function, compile a numerical control machining program, set the perforation hole diameter (typical value is 1.5 mm), the center distance between adjacent hole centers (typical value is 5.0 mm), and the regular hexagonal close-packed array arrangement. Then, use a high-precision numerical control drill press, select a cemented carbide drill bit, set the spindle speed at 8000 revolutions per minute, and the feed speed at 120 mm per minute. Conduct a trial drilling test, use a coordinate measuring machine to detect the perforation accuracy, and adjust the processing parameters until the accuracy requirements are met. Then, perform formal processing, check the drill bit every 100 holes drilled, and replace the drill bit if necessary. After processing, rinse the board with compressed air and water to remove the dust and debris generated during the drilling process. Finally, perform full-size inspection to ensure that the error of the perforation hole diameter is controlled within ±0.2 mm, the error of the center distance between adjacent hole centers is controlled within ±0.5 mm, and the deviation of the perforation rate from the design value does not exceed ±1%. The purpose of this step is to form an accurate perforation structure on the UHPC board to ensure the design requirements of the acoustic performance, and the high-precision processing ensures that the propagation path of sound waves in the material conforms to the expectations of the design model.

[0047] The specific implementation of step S05 is the fixation of the back strengthening layer. First, according to the size of the perforated UHPC board, cut the basalt fiber cloth or fiberglass board into the same size, leaving a 5-mm margin for later trimming during cutting; then, perform surface treatment on the back of the UHPC board, use sandpaper to polish off the floating slurry, and blow off the dust with compressed air to ensure the surface is clean and dry; next, prepare a two-component epoxy resin adhesive, mix it evenly according to the mass ratio of resin to curing agent of 2:1, and control the viscosity of the adhesive within 12,000 to 15,000 mPa·s; then, evenly coat the adhesive on the back of the UHPC board, with the thickness controlled within 0.8 to 1.2 mm; lay the basalt fiber cloth or fiberglass board on the adhesive layer, and roll it with a rubber roller from the center to the periphery to remove air bubbles and ensure full bonding; finally, let it stand and cure at room temperature of 20±5°C for 24 to 36 hours. The purpose of this step is to enhance the flexibility of the UHPC board and improve the acoustic performance. The basalt fiber cloth or fiberglass board, as a porous sound-absorbing material, can absorb the sound wave energy passing through the holes of the UHPC board and improve the mid-low frequency sound absorption effect.

[0048] The specific implementation of step S06 is the surface protection treatment. First, clean the surface of the perforated UHPC board, gently polish the surface with fine sandpaper to remove dirt and loose substances, and then wipe it with alcohol to ensure the surface is clean and dust-free; then, prepare nano-silica sol, select silica with a particle size of 10 to 30 nm, a solid content of 30% to 35%, and the pH value controlled within the range of 9.0 to 10.0, and add 0.5% of organosilane coupling agent to improve the compatibility between the sol and the UHPC substrate; next, use the spraying method to evenly coat the sol on the surface of the UHPC board, including the inner wall of the holes, with the spraying pressure controlled within 0.3 to 0.4 MPa, and the distance between the nozzle and the board surface maintained at 20 to 30 cm; after coating, dry and cure it in an environment with a temperature of 25±3°C and a relative humidity of 60% to 70%, and the curing time is 16 hours; finally, use a non-contact thickness gauge to measure the coating thickness to ensure that the thickness is within the range of 0.5 to 1.0 mm, and the uniformity deviation does not exceed ±0.2 mm. The purpose of this step is to improve the waterproof and moisture-proof performance of the material while ensuring the acoustic performance. The nano-silica sol forms a microscopic porous structure after curing, which can both waterproof and moisture-proof without affecting the sound wave permeability.

[0049] The specific implementation of step S07 is acoustic performance evaluation. First, an acoustic performance evaluation function is constructed. This function is based on the sound transmission loss theory and the sound absorption mechanism of micro-perforated plates. The perforation diameter, center-to-center distance of adjacent holes, perforation rate, regular hexagonal close-packed array arrangement, and UHPC plate thickness determined in step S01 are input, and the predicted sound absorption coefficients at different frequencies are output. Then, according to the GB / T18696.2 standard, circular specimens with a diameter of 100 mm are prepared for low-frequency band (125 Hz to 1000 Hz) testing, and circular specimens with a diameter of 30 mm are prepared for high-frequency band (1000 Hz to 4000 Hz) testing. Next, the impedance tube method is used to test the sound absorption coefficient. The test frequency points include six standard frequency points: 125 Hz, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz. The average value is taken after measuring 3 times at each frequency point. The test results are compared and analyzed with the predicted values, and the root mean square error and correlation coefficient are calculated to verify the accuracy of the evaluation function. Finally, the sound absorption coefficient-frequency curve is plotted, and the average sound absorption coefficient in the middle frequency band (500 Hz to 2000 Hz) and the average sound absorption coefficient in the high frequency band (2000 Hz to 4000 Hz) are calculated to ensure that the sound absorption coefficient in the middle frequency band is not less than 0.7 and the sound absorption coefficient in the high frequency band is not less than 0.9. The purpose of this step is to verify whether the acoustic performance of the composite material meets the design requirements and ensure its excellent sound absorption effect in building acoustics applications.

[0050] The specific implementation of step S08 is fire performance testing. First, according to the GB8624 standard, specimens with dimensions of 230 mm × 140 mm are prepared for combustion performance grading testing. Then, a single burning test is carried out. The specimen is vertically fixed on the test rack, and a heat source is applied at a height of 35 mm with a propane flame. The flame power is 1 kW, and the action time is 30 s. Record the starting time of specimen heating, ignition time, combustion duration, and flame spread distance. Next, the heat release rate test is carried out. The peak heat release rate and total heat release of the specimen are measured using a cone calorimeter under a heat flux of 50 kW / m². Then, the smoke toxicity test is carried out. The specimen is burned in a closed chamber, and the smoke sample is collected to analyze the content of toxic gases such as CO, CO 2 , HCl, and HCN. Finally, the fire resistance limit test is carried out. According to the GB / T9978 standard, the specimen is made into a size of 1 m × 1 m, and the standard fire temperature curve is applied for heating in a furnace, and the time for maintaining the structural integrity is recorded to ensure that the fire resistance limit is not less than 2 hours. The purpose of this step is to evaluate the fire safety performance of the composite material, ensure that it meets the requirements of Class A fire protection grade for building materials, and is applicable to public buildings with high fire safety requirements.

[0051] The specific implementation of step S09 is the waterproof and moisture-proof performance test. First, according to the GB / T5486 standard, specimens with a size of 100 mm × 100 mm are prepared for the water absorption test; then the specimens are dried to a constant weight at 105 ± 5 °C, and the initial mass m is recorded. 1 The specimens are immersed in clean water at 23 ± 2 °C for 24 hours, taken out, and the surface moisture is wiped off with a wet cloth, and the mass m is measured and determined. 2 , and the water absorption rate is calculated as = (m 2 - m 1 ) / m 1 × 100%, ensuring that the water absorption rate is less than 3%; then the damp and hot environment cycle test is carried out. The specimens are placed in a damp and hot test chamber and kept at 50 °C and a relative humidity of 95% for 8 hours, and then kept at 20 °C and a relative humidity of 65% for 16 hours as a cycle period, and 50 cycles are carried out continuously; after the cycle test, the water absorption rate, flexural strength, and sound absorption coefficient of the specimens are measured again, and the performance attenuation rate is calculated by comparing with the initial values to ensure that the performance attenuation does not exceed 5%; finally, the cold and hot cycle test is carried out. The specimens are kept in an environment of -20 °C for 4 hours, and then in an environment of 60 °C for 4 hours. After 30 cycles, the appearance and performance changes are detected. The purpose of this step is to evaluate the durability of the composite material under humid environments and temperature change conditions, and ensure that it has long-term stable acoustic performance and structural performance in practical applications.

[0052] Further, the steps for establishing the two-layer nested optimization function system specifically include:

[0053] The first step: Construct the basic model framework of the acoustic parameter optimization function and the structural parameter optimization function. Through the theoretical acoustic model and finite element analysis, establish the mathematical expressions of the acoustic performance and structural performance of the perforated UHPC plate, and model the relationships between parameters such as the perforation diameter, the center distance between adjacent hole centers, the perforation rate, the regular hexagon close-packed array arrangement, and the UHPC plate thickness and performance indicators such as the sound absorption coefficient and structural strength. At the same time, determine the constraint conditions and limitation ranges of each parameter, laying a theoretical foundation for subsequent optimization calculations;

[0054] The second step: Use the orthogonal experimental design method to determine the test points of the key parameter combinations. According to the model framework established in the first step, for the perforation diameter in the range of 0.5 mm to 3.0 mm, the center distance between adjacent hole centers in the range of 1.5 mm to 10.0 mm, the perforation rate in the range of 10% to 40%, the UHPC plate thickness in the range of 8 mm to 30 mm, and different regular hexagon close-packed array arrangement methods, design an L16(45) orthogonal experimental scheme to ensure that the test points are evenly distributed in the entire parameter space, fully reflecting the influence of each parameter and its interaction on the performance;

[0055] Step 3: Conduct experimental tests on acoustic performance and structural performance. Prepare perforated UHPC plate specimens with different parameter combinations according to the orthogonal experimental design scheme. Test the sound absorption coefficient curves of each specimen in the frequency range of 125 Hz to 4000 Hz through the impedance tube method. At the same time, test the structural performance indexes such as flexural strength, compressive strength, and elastic modulus of each specimen through static tests, and collect a complete experimental data matrix to provide an experimental basis for subsequent function fitting;

[0056] Step 4: Identify and mark the preferred experimental data points. Analyze the experimental data obtained in Step 3 through a comprehensive evaluation method, determine the parameter combinations with a sound absorption coefficient above 0.7 in the mid-frequency band and above 0.9 in the high-frequency band, and at the same time meet the structural strength requirements. Mark these preferred experimental data points as high-performance points to provide key references for subsequent data augmentation and function fitting;

[0057] Step 5: Adjust the weights of the preferred experimental data and perform data augmentation. For the preferred experimental data points marked in Step 4, use the small-range parameter perturbation technique for data augmentation. Add virtual test points in the parameter space around the original preferred data points, and assign performance indexes similar to those of the original preferred data points to these augmented data points. At the same time, assign higher weight coefficients to these data points in the fitting function to ensure that the fitting function has higher accuracy and reliability in the preferred parameter region;

[0058] Step 6: Use the enhanced dataset to fit the acoustic parameter optimization function and the structural parameter optimization function. Adopt the multiple nonlinear regression analysis method. Based on the complete dataset obtained in Steps 3 to 5, fit and establish the acoustic parameter optimization function between the perforation diameter, the center distance of adjacent hole centers, the perforation rate, and the sound absorption coefficient, and the structural parameter optimization function between the regular hexagonal close-packed array arrangement and the UHPC plate thickness and the structural performance. Evaluate the function fitting accuracy through the cross-validation technique to ensure that the fitting function can accurately predict the performance under different parameter combinations;

[0059] Step 7: Design a multi-objective optimization algorithm for the combined optimization function. Based on the output results of the acoustic parameter optimization function and the structural parameter optimization function, construct a combined optimization function that includes multiple optimization objectives such as acoustic performance, structural performance, manufacturing process, and cost-benefit. Adopt intelligent optimization algorithms such as genetic algorithm, particle swarm optimization, or simulated annealing, design the fitness function and the convergence criterion, and provide algorithm support for the solution of the global optimal parameter combination;

[0060] Step 8: Conduct sensitivity analysis and parameter space exploration. Through the global sensitivity analysis method, study the influence degree and interaction of each parameter on the final performance, determine the key sensitive parameters and conduct a more refined parameter space exploration for these parameters. At the same time, analyze the feasibility and robustness of different parameter combinations in actual engineering applications to ensure that the optimization results have engineering practical value;

[0061] Step 9: Solve and verify the global optimal parameter combination. Comprehensively apply the acoustic parameter optimization function, structural parameter optimization function and combined optimization function, and solve the global optimal parameter combination that meets the multi-objective optimization requirements through iterative calculation to obtain the optimal values of the perforation aperture, center distance between adjacent hole centers, perforation rate, regular hexagonal close-packed array arrangement and UHPC plate thickness. And conduct experimental tests by preparing verification samples to verify the accuracy and reliability of the optimization results, and form the final optimal parameter vector of the perforated UHPC plate.

[0062] The following details the mathematical models or calculation processes involved in the present invention.

[0063] In step S01, the two-layer nested optimization function system involves multiple calculation processes and mathematical models. The acoustic parameter optimization function is based on the Delft - Eindhoven model, and is specifically expressed as follows:

[0064]

[0065] In the formula, Z p is the complex acoustic impedance of the perforated plate, with the unit of Pa·s / m; ρ 0 is the air density, with a value of 1.21 kg / m 3 ; c 0 is the speed of sound in air, with a value of 343 m / s; φ is the perforation rate, ranging from 0.1 to 0.4; η is the air dynamic viscosity coefficient, with a value of 1.81×10 -5 Pa·s; ω is the angular frequency, with the unit of rad / s, and the calculation method is ω = 2πf, where f is the acoustic wave frequency, with the unit of Hz; d is the perforation aperture, ranging from 0.5 to 3.0 mm; σ is the flow resistance, and the calculation method is where t is the plate thickness, ranging from 8 to 30 mm.

[0066] The acoustic impedance Z p includes a real part and an imaginary part, corresponding to the damping and mass effects of the acoustic wave respectively. This model considers the influence of parameters such as aperture, perforation rate, and plate thickness on the acoustic impedance. Its design principle is to regard the perforated structure as a distributed Helmholtz resonator and adjust the resonance frequency to match the target absorption frequency band.

[0067] Based on the acoustic impedance, the sound absorption coefficient calculation formula is as follows:

[0068]

[0069] Wherein, α(ω) is the sound absorption coefficient at a specific angular frequency ω, with a range of 0 to 1; the meanings of other parameters are the same as above.

[0070] The acoustic parameter optimization objective function is expressed as:

[0071]

[0072] Wherein, F acoustic is the value of the acoustic optimization objective function; d is the perforation aperture; s is the center distance between adjacent holes; φ is the perforation ratio, and α target (f i ) is the target sound absorption coefficient at frequency f i ; α actual (f i , d, s, φ) is the actually calculated sound absorption coefficient at frequency f i ; w i is the weight coefficient at the i-th frequency point. The weight in the middle frequency band is taken as 0.5, the weight in the high frequency band is taken as 0.3, and the weight in the low frequency band is taken as 0.2; n is the number of frequency sampling points, with a value of 20, evenly distributed in the range of 125 to 4000 Hz.

[0073] The structural parameter optimization function is based on the meso-mechanics model and is specifically expressed as follows:

[0074]

[0075] Wherein, σ flex is the equivalent bending strength, with the unit of MPa; F is the fracture load, with the unit of N, measured through a three-point bending test; L is the span, with the unit of mm; b is the specimen width, with the unit of mm; t is the plate thickness, with the unit of mm; φ is the perforation ratio; β is the structural weakening coefficient, considering the influence of the perforation arrangement pattern. For the regular hexagonal close-packed array arrangement, β = 1.2, and this coefficient is determined through finite element analysis and experimental verification.

[0076] The structural parameter optimization objective function is expressed as:

[0077] F structure (p, t) = w 1 (30 - σ flex ) 2 + w 2 (2000 - K IC ) 2 ;

[0078] Wherein, F structure is the value of the structural optimization objective function; p is the parameter of the regular hexagonal close-packed array arrangement, including the arrangement angle θ and the density factor λ; t is the plate thickness; σ flexis the equivalent bending strength, with the unit of megapascal; K IC is the fracture toughness, with the unit of joule per meter 2 , determined by the wedge splitting test; w 1 and w 2 are the weight coefficients, taking 0.6 and 0.4 respectively.

[0079] The combined optimization function is expressed as:

[0080] F combined (d, s, φ, p, t) = 0.5F acoustic (d, s, φ) + 0.3F structure (p, t) + 0.2F cost (d, s, φ, p, t);

[0081] In the formula, F combined is the combined optimization objective function value; F acoustic is the acoustic optimization objective function value; F structure is the structural optimization objective function value; F cost is the cost function, and the calculation formula is F cost = c 1 m material + c 2 t process + c 3 n holes , where c 1 is the unit price coefficient of the material, with the value of 0.01; c 2 is the processing time coefficient, with the value of 0.2; c 3 is the number of perforations coefficient, with the value of 0.005; m material is the material quality, with the unit of kilogram; t process is the total processing time, with the unit of hour; n holes is the total number of perforations.

[0082] The solution process of the adaptive genetic algorithm includes:

[0083] Initial population generation: P 0 = {x 1 , x 2 ,..., x N}, where x i = (d i , s i , φ i , p i , t i ) is the individual parameter vector, and N is the population size, with the value of 100;

[0084] Fitness function:

[0085] Crossover operation: x new = αx i + (1 - α)x j , where α is a random factor with a range of 0 to 1;

[0086] Mutation operation: x new = x i + β·N(0, 1), where β is the adaptive mutation step size and N(0, 1) is a standard normal distribution random number;

[0087] Iteration termination condition: Reach the maximum number of iterations of 500 generations, or the change in the optimal solution is less than 0.001 for 30 consecutive generations.

[0088] In step S07, the acoustic performance evaluation function involves the calculation of the sound absorption coefficient and the prediction of acoustic performance. The acoustic performance evaluation function is expressed as follows:

[0089] α composite (f) = α perf (f)+ (1 - α perf (f))·α back (f)·e -2δ(f) ;

[0090] In the formula, α composite (f) is the sound absorption coefficient of the composite material at frequency f; α perf (f) is the sound absorption coefficient of the perforated UHPC plate at frequency f, and the calculation method is the same as in step S01; α back (f) is the sound absorption coefficient of the back reinforcement layer (basalt fiber cloth or fiberglass board) at frequency f, which is directly measured by the impedance tube method; δ(f) is the attenuation coefficient of sound wave propagation in the perforation, and the calculation formula is where f is the frequency, c 0 is the speed of sound, η is the aerodynamic viscosity coefficient, d is the pore diameter, ρ 0 is the air density, and t is the plate thickness.

[0091] Comprehensive acoustic performance score calculation formula:

[0092]

[0093] In the formula, S acoustic is the comprehensive acoustic performance score, with a range of 0 to 1; is the average sound absorption coefficient in the low frequency band (125 - 500 Hz); is the average sound absorption coefficient in the middle frequency band (500 - 2000 Hz); is the average sound absorption coefficient in the high frequency band (2000 - 4000 Hz). The calculation method of the average sound absorption coefficient in each frequency band is:

[0094]

[0095] In the formula, is the average sound absorption coefficient of a specific frequency band; α(f i ) is the sound absorption coefficient at frequency f i ; n band is the number of sampling points within this frequency band.

[0096] The consideration of the two-layer nested optimization function co-optimizes the acoustic performance and the structural performance as two mutually restrictive optimization objectives, achieves multi-objective balance through weight adjustment, and takes into account the manufacturing process and cost factors, making the final parameter combination not only excellent in theoretical performance but also having engineering practicability.

[0097] Specifically, the principle of the present invention is as follows: The technical principle of the present invention is based on the deep integration of acoustic mechanism and materials science, and realizes the synergistic effect of each function through systematic optimization design and multi-layer composite structure. First, based on the sound absorption principle of the micro-perforated plate, when sound waves are incident on the surface of the perforated plate, the sound waves propagate through the holes with precise dimensions, generating viscous loss and heat conduction loss in the channels, and converting the sound energy into heat energy. The two-layer nested optimization function system adopted by the present invention can accurately calculate the optimal combination of perforation parameters, enabling the composite material to achieve the optimal sound absorption performance within the target frequency band. The regular hexagonal close-packed array arrangement not only improves the diffusion effect of sound waves but also enhances the overall structural strength of the perforated plate.

[0098] In terms of material selection, UHPC (Ultra-High Performance Concrete) has ultra-high strength and durability, and can accurately maintain the micro-perforated structure, while the added polypropylene fibers enhance the toughness and crack resistance of UHPC. The basalt fiber cloth backing layer not only provides additional sound absorption effect but also has excellent high-temperature resistance, and can maintain the structural stability in a fire environment without generating toxic gases. The nano-silica sol coating forms a nano-level dense protection network, effectively blocking the penetration of moisture and humidity, while not affecting the propagation and absorption of sound waves.

[0099] The synergistic mechanism of this multi-layer composite structure lies in: the perforated UHPC plate provides the main sound absorption function and structural support, the basalt fiber cloth enhances the mid-low frequency sound absorption effect and provides high-temperature protection, and the nano-coating ensures the stable performance of the material in a humid environment. By balancing various performance indicators through a multi-objective optimization algorithm, the contradiction of mutual restriction of performance in traditional materials is solved. In addition, the precise preparation process and strict quality control ensure the accurate realization of the theoretical design in actual products, enabling the composite material to maintain excellent comprehensive performance in various extreme environments.

[0100] The following provides a specific Embodiment 1 of the present invention, and the specific implementation manners of each step in this Embodiment 1 are described in detail as follows.

[0101] The specific implementation of step S01 is to establish a two-layer nested optimization function system for perforated UHPC plate parameter optimization calculation. First, an acoustic parameter optimization function is constructed. This function is based on the Delft - Eindhoven model to establish the mathematical expression of the sound absorption mechanism of the perforated plate, taking the perforation diameter, the center distance between adjacent hole centers, and the perforation rate as input variables, and the target sound absorption coefficient curve in the frequency band from 125 Hz to 4000 Hz as the optimization objective. The core of the acoustic parameter optimization function is to calculate the acoustic impedance of the perforated plate, which is specifically expressed as follows: In the formula, Z p is the complex acoustic impedance of the perforated plate, with the unit of Pa·s / m; ρ 0 is the air density, with a value of 1.21 kg / m 3 ; c 0 is the speed of sound in air, with a value of 343 m / s; φ is the perforation rate, ranging from 0.1 to 0.4; η is the air dynamic viscosity coefficient, with a value of 1.81×10 -5 Pa·s; ω is the angular frequency, with the unit of rad / s, and the calculation method is ω = 2πf, where f is the sound wave frequency, with the unit of Hz; d is the perforation diameter, ranging from 0.5 to 3.0 mm; σ is the flow resistance, and the calculation method is where t is the plate thickness, ranging from 8 to 30 mm. Based on the acoustic impedance, the sound absorption coefficient calculation formula is: In the formula, α(ω) is the sound absorption coefficient at a specific angular frequency ω, ranging from 0 to 1. The acoustic parameter optimization objective function is expressed as: In the formula, F acoustic is the value of the acoustic optimization objective function; d is the perforation diameter; s is the center distance between adjacent hole centers; φ is the perforation rate, and α target (f) is the target sound absorption coefficient at frequency f i ; α actual (f i , d, s, φ) is the actually calculated sound absorption coefficient at frequency f i ; w iis the weight coefficient at the i-th frequency point. The weight in the middle frequency band is 0.5, the weight in the high frequency band is 0.3, and the weight in the low frequency band is 0.2; n is the number of frequency sampling points, with a value of 20, evenly distributed in the range of 125 - 4000 Hz. The mapping relationship between parameters and performance is constructed by the multi-response surface method, and the gradient descent algorithm is used to solve the optimal combination of acoustic parameters. This combination needs to ensure that the sound absorption coefficient in the middle frequency band (500 Hz to 2000 Hz) is not less than 0.7, and the sound absorption coefficient in the high frequency band (2000 Hz to 4000 Hz) is not less than 0.9. Then, a structural parameter optimization function is constructed. This function is based on the meso-mechanics model and finite element analysis, taking the arrangement parameters of the regular hexagonal close-packed array and the thickness of the UHPC plate as input variables, with the flexural strength not less than 30 MPa and the impact toughness not less than 2000 J / m 2 as the constraint conditions. The structural parameter optimization function is expressed as: In the formula, σ flex is the equivalent flexural strength, with the unit of MPa; F is the fracture load, with the unit of N, measured through the three-point bending test; L is the span, with the unit of mm; b is the specimen width, with the unit of mm; t is the plate thickness, with the unit of mm; φ is the perforation rate; β is the structure weakening coefficient, considering the influence of the perforation arrangement pattern. For the regular hexagonal close-packed array arrangement, β = 1.2, and this coefficient is determined through finite element analysis and experimental verification. The structural parameter optimization objective function is: F structure (p, t) = w 1 (30 - σ flex ) 2 + w 2 (2000 - K IC ) 2 ; In the formula, F structure is the value of the structure optimization objective function; p is the arrangement parameter of the regular hexagonal close-packed array, including the arrangement angle θ and the density factor λ; t is the plate thickness; σ flex is the equivalent flexural strength, with the unit of MPa; K IC is the fracture toughness, with the unit of J / m 2 , measured through the wedge splitting test; w 1 and w 2 are the weight coefficients, taking 0.6 and 0.4 respectively. The optimal combination of structural parameters is solved by the Lagrange multiplier method. Finally, a combined optimization function is constructed. This function takes the result sets of acoustic parameter optimization and structural parameter optimization as the initial solution space, and introduces manufacturing process constraint conditions (such as aperture accuracy ±0.2 mm, hole pitch accuracy ±0.5 mm) and cost factors (the weighted sum of raw material cost, processing cost, and time cost). The combined optimization function is expressed as: F combined (d, s, φ, p, t) = 0.5F acoustic (d, s, φ) + 0.3F structure (p, t) + 0.2Fcost (d, s, φ, p, t); where F combined is the value of the combinatorial optimization objective function; F cost is the cost function, and its calculation formula is F cost = c 1 m material + c 2 t process + c 3 n holes , where c 1 is the unit price coefficient of the material, with a value of 0.01; c 2 is the processing time coefficient, with a value of 0.2; c 3 is the number of perforations coefficient, with a value of 0.005; m material is the material quality, in kilograms; t process is the total processing time, in hours; n holes is the total number of perforations. The adaptive genetic algorithm is used for global search, and the optimization objective function is the weighted sum of the acoustic performance score (weight 0.5), the structural performance score (weight 0.3), and the economic performance score (weight 0.2). The solution process of the adaptive genetic algorithm includes: Initial population generation: P 0 = {x 1 , x 2 ,..., x N}, where x i = (d i , s i , φ i , p i , t i ) is the individual parameter vector, N is the population size, with a value of 100; Fitness function: Crossover operation: x new = αx i + (1 - α)x j , where α is a random factor, ranging from 0 to 1; Mutation operation: x new = x i + β·N(0, 1), where β is the adaptive mutation step size, and N(0, 1) is a standard normal distribution random number; Iteration termination condition: reaching the maximum number of iterations of 500 generations, or the change in the optimal solution being less than 0.001 for 30 consecutive generations. The parameter vector is output through 500 generations of iterative calculations. The purpose of this step is to ensure that the design parameters simultaneously meet the requirements of acoustic performance and structural performance, and balance manufacturing feasibility and economy.

[0102] The specific implementation manners of steps S02 - S06 are the same as those described above, and will not be elaborated here.

[0103] The specific implementation of step S07 is acoustic performance evaluation. First, an acoustic performance evaluation function is constructed. This function is based on the sound transmission loss theory and the sound absorption mechanism of micro-perforated plates. The perforation aperture, the center distance between adjacent hole centers, the perforation rate, the regular hexagonal close-packed array arrangement, and the UHPC plate thickness determined in step S01 are input, and the predicted sound absorption coefficients at different frequencies are output. The acoustic performance evaluation function is expressed as follows: α composite (f) = α perf (f) + (1 - α perf (f))·α back (f)·e -2δ(f) ; where, α composite (f) is the sound absorption coefficient of the composite material at frequency f; α perf (f) is the sound absorption coefficient of the perforated UHPC plate at frequency f, and the calculation method is the same as that in step S01; α back (f) is the sound absorption coefficient of the back reinforcement layer (basalt fiber cloth or fiberglass board) at frequency f, which is directly measured by the impedance tube method; δ(f) is the attenuation coefficient of the sound wave propagating in the perforation, and the calculation formula is where f is the frequency, c 0 is the speed of sound, η is the air dynamic viscosity coefficient, d is the aperture, ρ 0 is the air density, and t is the plate thickness. The calculation formula for the comprehensive acoustic performance score: where, S acoustic is the comprehensive acoustic performance score, and the range is 0 to 1; is the average sound absorption coefficient in the low-frequency band (125 - 500 Hz); is the average sound absorption coefficient in the middle-frequency band (500 - 2000 Hz); is the average sound absorption coefficient in the high-frequency band (2000 - 4000 Hz). The calculation method for the average sound absorption coefficient in each frequency band is: where, is the average sound absorption coefficient in a specific frequency band; α(f i ) is the sound absorption coefficient at frequency f i ; n bandis the number of sampling points in this frequency band. Then, according to the GB / T 18696.2 standard, circular specimens with a diameter of 100 mm are prepared for testing in the low-frequency band (125 Hz to 1000 Hz), and circular specimens with a diameter of 30 mm are prepared for testing in the high-frequency band (1000 Hz to 4000 Hz). Next, the impedance tube method is used to test the sound absorption coefficient. The test frequency points include six standard frequency points: 125 Hz, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz. The measurement is taken 3 times at each frequency point and the average value is obtained. The test results are compared and analyzed with the predicted values, and the root mean square error and correlation coefficient are calculated to verify the accuracy of the evaluation function. Finally, the sound absorption coefficient-frequency curve is plotted, and the average sound absorption coefficient in the mid-frequency band (500 Hz to 2000 Hz) and the average sound absorption coefficient in the high-frequency band (2000 Hz to 4000 Hz) are calculated to ensure that the sound absorption coefficient in the mid-frequency band is not less than 0.7 and the sound absorption coefficient in the high-frequency band is not less than 0.9. The purpose of this step is to verify whether the acoustic performance of the composite material meets the design requirements and ensure its excellent sound absorption effect in building acoustics applications.

[0104] The specific implementation manners of steps S08 - S09 are the same as those described above and will not be elaborated here.

[0105] Through the implementation of the above 9 steps, a perforated UHPC board fireproof, high-temperature resistant, waterproof and moisture-proof strong sound absorption composite material with excellent acoustic performance, structural performance and durability can be prepared. This material uses a two-layer nested optimization function system for parameter optimization design to ensure the optimal coordination of acoustic performance and structural performance, and improves the comprehensive performance and application range of the material through fireproof, high-temperature resistant, waterproof and moisture-proof treatments. In particular, the mathematical model and optimization algorithm adopted in steps S01 and S07 provide a theoretical basis and quantitative means for the design and performance evaluation of the composite material, making the material performance predictable and controllable. At the same time, manufacturing process constraints and cost factors are considered, and it has strong engineering practical value. This material can be widely applied to building environments that need to simultaneously meet the requirements of sound absorption and noise reduction, fire safety and durability, such as public buildings like concert halls, theaters, conference centers, subway stations, high-speed railway stations, etc., as well as places with serious noise pollution such as industrial factories and machine rooms.

[0106] To better understand and implement the present invention, Example 2 of a specific application scenario of the present invention is provided below: A research team, aiming at the need of sound absorption and noise reduction in a concert hall, utilized the technology of a perforated UHPC board fireproof, high-temperature resistant, waterproof and moisture-proof strong sound absorption composite material to conduct a series of parameter optimizations and performance tests, and finally successfully applied it to the acoustic design and renovation of a certain concert hall.

[0107] First, the parameter optimization calculation of the perforated UHPC plate was carried out. The calculation was performed using a two-layer nested optimization function system. Through the acoustic parameter optimization function, a mathematical model of the acoustic impedance and sound absorption coefficient of the perforated plate was constructed. According to the acoustic requirements of the concert hall, the target sound absorption coefficient in the low-frequency band (125 - 500 Hz) was determined to be 0.5, in the middle-frequency band (500 - 2000 Hz) was 0.8, and in the high-frequency band (2000 - 4000 Hz) was 0.95. Based on the Delft - Eindhoven model, the acoustic parameter optimization calculation was carried out, while considering the structural parameter optimization and manufacturing process constraints. The iterative solution was carried out through the adaptive genetic algorithm. After 500 generations of iteration, several groups of feasible parameter combinations as shown in Table 1 were obtained.

[0108] Table 1 Optimization Parameter Combination Table of Perforated UHPC Plate

[0109]

[0110] According to the comprehensive score, the parameter combination A2 was selected as the optimal design scheme. Its perforation aperture was 1.5 mm, the center distance between adjacent hole centers was 5.2 mm, the perforation rate was 18.7%, and it was arranged in a regular hexagonal close-packed array (arrangement angle was 0°). The thickness of the UHPC plate was 15 mm.

[0111] Subsequently, the UHPC slurry was prepared. By mass, 100 parts of P·II 52.5 Portland cement, 25 parts of silica fume with a specific surface area of 30,000 m² / kg, 120 parts of quartz sand with a particle size of 0.1 - 0.5 mm, 2 parts of polycarboxylate superplasticizer with a water reduction rate of 30%, and 32 parts of water were used. First, the cement and silica fume were mixed evenly and stirred at a speed of 2000 revolutions per minute for 3 minutes using a high-speed mixer. Then, the quartz sand was added and stirred for another 2 minutes. Next, the superplasticizer was dissolved in water and slowly added to the dry mixture, and it was stirred at a low speed for 5 minutes and then at a medium speed for 3 minutes. Finally, polypropylene fibers with a length of 12 mm and a diameter of 0.2 mm were added, with a volume fraction of 2%, and stirred for another 2 minutes to obtain UHPC slurry with a fluidity of 280 mm.

[0112] During the pouring and curing process, a steel mold of 600 mm × 600 mm × 15 mm was used. After pouring, it was vibrated on a vibrating table at a frequency of 50 Hz for 30 seconds, and then a vacuum negative pressure of 0.08 MPa was applied for 10 minutes. Then, it was cured in a constant temperature and humidity curing chamber (20°C, relative humidity 95%) for 5 hours until initial setting, and then transferred to a steam curing box and heated to 85°C at a rate of 10°C / hour, maintained for 24 hours, and then cooled to room temperature at a rate of 5°C / hour. After demolding, it was continuously cured under standard conditions for 7 days. The test results showed that the prepared UHPC plate had a compressive strength of 155 MPa, a flexural strength of 28 MPa, and a dense and smooth surface.

[0113] The UHPC board is precisely perforated using a high-precision CNC drill press. The perforation hole diameter is set at 1.5 mm, the center distance between adjacent hole centers is 5.2 mm, and they are arranged in a regular hexagonal close-packed array. A cemented carbide drill bit with a diameter of 1.5 mm is selected, the spindle speed is 8000 revolutions per minute, and the feed rate is 120 mm per minute for processing. After drilling, 10% of the perforations are inspected. The measured value of the perforation hole diameter is 1.48 ± 0.12 mm, the measured value of the center distance between adjacent hole centers is 5.23 ± 0.26 mm, and the perforation rate is 18.5%, meeting the accuracy requirements.

[0114] For the fixation of the back reinforcement layer, basalt fiber cloth with a thickness of 2 mm is used, cut into 605 mm × 605 mm. A two-component epoxy resin adhesive (mass ratio of resin to curing agent is 2:1, viscosity is 13500 mPa·s) is evenly coated on the back of the UHPC board to form an adhesive layer with a thickness of 1.0 mm. The basalt fiber cloth is laid and rolled for fixation, and cured at 20 °C for 30 hours. The results of the bond strength test are shown in Table 2. Each test point exceeds 2.0 MPa, meeting the design requirements.

[0115] Table 2 Test Results of the Bond Strength of the Back Reinforcement Layer

[0116] Test point number Bonding strength (MPa) Failure mode 1 2.35 Interface failure 2 2.42 Interface failure 3 2.56 Internal failure of basalt fiber cloth 4 2.48 Interface failure 5 2.61 Internal failure of basalt fiber cloth Average value 2.48 -

[0117] For the surface protection treatment, silica sol with a particle size of 15 nm is used, the solid content is 32%, the pH value is 9.5, and 0.5% of γ-aminopropyltriethoxysilane coupling agent is added. It is evenly sprayed using a spraying device under a pressure of 0.35 MPa, and the distance between the nozzle and the board surface is kept at 25 cm. It is cured for 16 hours in an environment of 25 °C and a relative humidity of 65%. The coating thickness is 0.75 ± 0.15 mm, and the uniformity is good.

[0118] The results of the acoustic performance evaluation are shown in Table 3. The sound absorption coefficients at six standard frequency points are measured using the impedance tube method. The average value is taken after measuring 3 times at each frequency point. The average sound absorption coefficient in the middle frequency band is calculated to be 0.83, and the average sound absorption coefficient in the high frequency band is 0.92, meeting the design requirements.

[0119] Table 3 Test Results of Acoustic Performance

[0120] Frequency (Hz) Theoretical predicted sound absorption coefficient Measured sound absorption coefficient Relative error (%) 125 0.32 0.29 9.4 250 0.48 0.45 6.3 500 0.76 0.72 5.3 1000 0.85 0.88 -3.5 2000 0.91 0.89 2.2 4000 0.95 0.94 1.1

[0121] The fire resistance performance test was carried out in accordance with the GB8624 standard. Specimens of 230 mm × 140 mm were prepared for the single burning test. The test results showed that there was no obvious burning phenomenon after the material was under the action of a 1-kilowatt flame for 30 seconds, and the flame spread distance was less than 15 mm. The peak value of the heat release rate was 28 kW / m², the total heat release was 2.5 MJ / m², and the flue gas toxicity met the requirements of Class A materials. The fire resistance limit test results showed that the time for the material to maintain structural integrity under the standard fire temperature curve was 135 minutes, meeting the fire resistance limit requirement of more than 2 hours.

[0122] The test results of the waterproof and moisture-proof performance are shown in Table 4. The initial water absorption rate measured in accordance with the GB / T5486 standard was 2.35%, and the water absorption rate was 2.47% after 50 wet and heat cycles, with a 5.1% increase in water absorption rate; the flexural strength decreased from 28 MPa to 26.8 MPa, a decrease of 4.3%; the average sound absorption coefficient in the middle frequency band decreased from 0.83 to 0.81, a decrease of 2.4%; the average sound absorption coefficient in the high frequency band decreased from 0.92 to 0.90, a decrease of 2.2%. The attenuation of each performance was less than 5%, meeting the design requirements.

[0123] Table 4 Comparison of performance before and after wet and heat cycles

[0124] Performance index Initial value After 50 times of damp heat cycling Change rate (%) Water absorption rate (%) 2.35 2.47 +5.1 Flexural strength (MPa) 28.0 26.8 -4.3 Average sound absorption coefficient in the middle frequency band 0.83 0.81 -2.4 Average sound absorption coefficient in the high frequency band 0.92 0.90 -2.2

[0125] Based on the above research results, the research team applied this perforated UHPC board fire-resistant, high-temperature-resistant, waterproof, moisture-proof, and strong sound-absorbing composite material to the acoustic design of a concert hall. A total of 320 square meters of composite material sound-absorbing panels were installed on the side walls and rear walls of the concert hall according to the design drawings. After installation, on-site acoustic tests were carried out. The results showed that: the reverberation time in the hall decreased from the original 2.1 seconds to 1.4 seconds, reaching the optimal reverberation time range for a medium-sized concert hall; the speech intelligibility index (STI) at each measurement point in the hall increased from an average of 0.52 to 0.68, reaching the "good" level; the background noise in the hall decreased from the original 35 dB to 28 dB, meeting the requirements of a high-quality concert hall.

[0126] Traditional building acoustic sound-absorbing materials mainly include porous materials (such as glass wool, mineral wool), micro-perforated plates, and resonant sound-absorbing structures, etc. These traditional materials have obvious deficiencies: although porous materials have good mid- and high-frequency sound-absorbing performance, they have poor fire resistance, are prone to dust accumulation and mildew, and have a short service life; ordinary micro-perforated plates have a narrow sound-absorbing frequency band and are difficult to meet the sound-absorbing requirements of both mid- and low-frequency and high-frequency at the same time; resonant sound-absorbing structures are large in volume, heavy in weight, and complex in installation. In addition, the design of traditional materials mostly relies on empirical formulas and repeated tests, lacking a systematic optimization method, and it is difficult to meet the requirements of acoustic performance, structural performance, and durability at the same time.

[0127] In contrast, the perforated UHPC board fireproof, high-temperature resistant, waterproof, moisture-proof and strong sound-absorbing composite material in this embodiment has the following obvious advantages: (1) By using a two-layer nested optimization function system for parameter optimization design, the synergy optimization of acoustic performance and structural performance is achieved. The sound absorption coefficient in the middle frequency band reaches 0.83, and the sound absorption coefficient in the high frequency band reaches 0.92. The sound absorption performance is significantly better than that of traditional micro-perforated plates; (2) Based on the perforated plate structure of UHPC, it has both high strength (compressive strength of 155 MPa) and good toughness, and can be used as a self-supporting structure, simplifying the installation process; (3) By using surface nano-silica sol protection treatment, the material has excellent waterproof and moisture-proof performance, with a water absorption rate of less than 3%, and the performance decay does not exceed 5% after 50 wet and heat cycles; (4) Through precise perforation technology and regular hexagon close-packed array arrangement, the directional absorption and diffusion of sound waves are achieved, improving the uniformity of the spatial sound field; (5) The material reaches Class A fire protection rating, and the fire resistance limit exceeds 2 hours, meeting the strict building fire safety requirements. These advantages make the material particularly suitable for high-quality concert halls, theaters, conference centers and other places with strict requirements for acoustic environment and safety.

[0128] It should be noted that the detailed explanations of the variables involved in the present invention are shown in Table 5 below.

[0129] Table 5 Variable Explanation Table

[0130]

[0131]

[0132] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention.

Claims

1. A method for preparing a perforated UHPC board with fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material, characterized in that: The method includes the following steps: using a two-layer nested optimization function system to calculate the optimal parameter vector of the perforated UHPC board and obtain the optimal parameter combination; preparing UHPC slurry and performing toughening treatment; pouring the slurry into a mold and curing it; performing precision perforation treatment on the cured UHPC board according to the optimal parameter combination; bonding and fixing basalt fiber cloth or glass fiber board to the back of the perforated UHPC board; coating the surface of the perforated UHPC board with nano-silica sol to form a waterproof and moisture-proof protective layer; applying an acoustic performance evaluation function to predict and test the acoustic performance of the composite material; performing fire resistance test and waterproof and moisture-proof performance test on the composite material to obtain the final material.

2. The method for preparing the fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material of perforated UHPC board according to claim 1 is characterized in that: A two-layer nested optimization function system is used to calculate the optimal parameter vector of the perforated UHPC plate. The acoustic parameter optimization function and the structural parameter optimization function are used to output the optimal acoustic parameter combination and the optimal structural parameter combination respectively. The combined optimization function then outputs the optimal parameter combination including the perforation diameter, the distance between the centers of adjacent holes, the perforation rate, the regular hexagonal close-packed array arrangement and the thickness of the UHPC plate.

3. The method for preparing the fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material of perforated UHPC board according to claim 2 is characterized in that: The UHPC slurry is prepared by mixing 100 parts of cement, 25 parts of silica fume, 120 parts of quartz sand, 2 parts of water, and 32 parts of water by weight. After mixing evenly, 2% by volume of polypropylene fiber is added for toughening treatment.

4. The method for preparing the fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material of perforated UHPC board according to claim 3 is characterized in that: The slurry is poured into the mold and cured. Specifically, the prepared UHPC slurry is poured into the mold, and the bubbles are expelled by the vacuum vibration process. After the initial setting is performed for 4 to 6 hours under standard curing conditions, steam curing is performed at 60°C to 90°C for 24 to 48 hours.

5. The method for preparing the fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material of perforated UHPC board according to claim 4, characterized in that: The UHPC plates that have been cured are precisely perforated according to the optimal parameter combination. Specifically, CNC drilling equipment is used for processing to ensure that the perforation diameter error is controlled within ±0.2 mm and the error of the distance between the centers of adjacent holes is controlled within ±0.5 mm.

6. The method for preparing the fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material of perforated UHPC board according to claim 5, characterized in that: The basalt fiber cloth or glass fiber board is bonded and fixed to the back of the perforated UHPC board. Specifically, the basalt fiber cloth or glass fiber board is cut into a shape with the same size as the perforated UHPC board, and epoxy resin adhesive is used to bond and fix the perforated UHPC board to the back of the perforated UHPC board, and the curing time is 24 hours to 36 hours.

7. The method for preparing the fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material of perforated UHPC board according to claim 6, characterized in that: The drying and curing time of the nano-silica sol coated on the surface of the perforated UHPC board is 12 hours to 24 hours, and the coating thickness is controlled at 0.5 mm to 1.0 mm.

8. The method for preparing the fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material of perforated UHPC board according to claim 7, characterized in that: The acoustic performance evaluation function is used to predict and test the acoustic performance of composite materials. Specifically, the acoustic performance evaluation function inputs the perforation diameter, adjacent hole center spacing, perforation rate, regular hexagonal close-packed array arrangement and UHPC board thickness determined by the acoustic parameter optimization function and the structural parameter optimization function, and the impedance tube method is used to measure the sound absorption coefficient. The frequency range is 125 Hz to 4000 Hz, ensuring that the sound absorption coefficient in the mid-frequency band is not less than 0.7, and the sound absorption coefficient in the high-frequency band is not less than 0.

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9. The method for preparing the fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material of perforated UHPC board according to claim 8, characterized in that: The two-layer nested optimization function system refers to a computing system that includes the first-layer optimization and the second-layer optimization. The first-layer optimization includes the acoustic parameter optimization function and the structural parameter optimization function. The second layer is a combined optimization function that constructs a parameter space within the scope of the first-layer results to balance the overall performance.

10. The method for preparing the fireproof, high temperature resistant, waterproof and moisture resistant strong sound absorbing composite material of perforated UHPC board according to claim 9, characterized in that: The acoustic parameter optimization function is used to solve the best matching relationship between perforation parameters. The input includes the target frequency range, expected sound absorption coefficient, perforation parameter constraints and material acoustic impedance characteristics. The output is the best combination of perforation aperture, adjacent hole center spacing and perforation rate that meets the acoustic performance requirements. The structural parameter optimization function is used to determine the best matching relationship between the perforation arrangement and the thickness of the UHPC board. The input includes load conditions, span requirements, deformation limits and perforation rate. The output is a combination of a regular hexagonal close-packed array arrangement and UHPC board thickness that meets the structural strength and stiffness requirements. The combined optimization function is used to balance the overall performance based on the two groups of optimization results in the first layer. The input includes the acoustic parameter optimization function result set, the structural parameter optimization function result set, the manufacturing process constraints and cost factors. The output is the optimal parameter combination that comprehensively considers acoustic performance, structural performance, manufacturing feasibility and cost-effectiveness.

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