Self-reinforced sound-absorbing cement-based material, preparation method and mix proportion design method

Abstract

The application discloses a self-reinforced sound-absorbing cement-based material and a preparation method and a mix proportion design method thereof, and belongs to the technical field of sound-absorbing cement-based materials. A self-reinforced sound-absorbing cement-based material is composed of the following components in parts by weight: 600 parts of cement, 300 parts of water, 30 parts of expanded perlite, 6 parts of a high-efficiency water reducing agent, 4.8 parts of a composite foam stabilizer, 75-800 parts of a functional foam material, 0.019-0.2 parts of an initiator and 0.01-0.1 parts of an accelerator. The cement-based sound-absorbing material of the application has an increasingly enhanced alkaline environment in the material with the continuous cement hydration reaction; the high polymer film responds to the endogenous high-alkaline environment and slowly chemically degrades; with the gradual rupture and dissolution of the film, the original closed pores are opened and converted into open pores in mutual communication; the gradually opened pore structure converts the pores into through holes, and the sound-absorbing function of the material is gradually enhanced; and finally, excellent sound-absorbing effect is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sound-absorbing cement-based materials, and particularly relates to a self-reinforced sound-absorbing cement-based material, a preparation method and a mix proportion design method. BACKGROUND

[0002] In recent years, in the process of modern urbanization, the noise pollution caused by traffic, industry and construction is increasingly serious, which seriously affects the comfort of the living environment and the physical and mental health of the public. Therefore, developing building materials with excellent sound-absorbing performance, good mechanical properties and durability has become a research hotspot in the field.

[0003] To improve the sound-absorbing performance of cement-based materials, many explorations have been made in the prior art. For example, Chinese patent CN119371225A discloses a high-efficiency sound-absorbing lightweight aggregate foam concrete and its preparation method and application. By constructing a multi-stage and multi-scale pore structure formed by expanded perlite, chemical foaming and physical foaming, and by optimizing the pore structure, a noise reduction coefficient of 0.80 or higher is achieved. Chinese patent CN118851645A discloses a steel slag and fly ash mixed alkali-activated sound-absorbing material and its preparation method. The sound-absorbing material prepared by alkali activation technology and physical foaming has a noise reduction coefficient of 0.45-0.6, and fully utilizes solid waste to reduce cost.

[0004] The above-mentioned prior art pursues high open porosity and complex pore structure to achieve excellent sound-absorbing effect. A large number of interconnected pores must be formed inside the material. Such a highly interconnected pore structure provides a possibility for the invasion of aggressive media in the external environment in the early stage of the service of the material.

[0005] The microstructure and strength of cement-based materials need to be fully developed through continuous hydration reaction within a certain curing period. In the early stage, especially in the case of immediately transporting the prefabricated components to the site for installation and service after demolding, the curing of the material is often insufficient, and the internal microstructure has not formed a dense C-S-H gel network, the strength is low, and the ability to resist environmental erosion is very weak. At this time, a large number of interconnected pores will accelerate the loss of internal moisture, leading to insufficient hydration and causing dry shrinkage cracking; at the same time, aggressive media can easily penetrate into the interior of the material through these pores, corrode the cement stone matrix, and destroy the pore structure.

[0006] Another Chinese patent, CN110255987A, discloses a cement-based porous foam sound-absorbing material. This material is produced by chemically foaming and then directly air-drying to leave pores. While this creates a sound-absorbing structure, the immediately formed open pores pose a serious challenge to its early mechanical properties and durability. Damage to the material's microstructure leads to a decrease in mechanical properties and can further block or destroy the originally designed precision sound-absorbing channels. Ultimately, this causes the sound-absorbing function to gradually deteriorate over time, severely impacting the long-term application value of the sound-absorbing material.

[0007] Chinese patent CN119263761A discloses a high-performance two-component rapid-setting grout and its preparation method. Through a two-component design, it utilizes methacrylic anhydride-modified sulfoaluminate cement reacting with a performance modifier containing multiple polymers, dual initiators, and crosslinking agents to achieve rapid setting and high performance. However, the aforementioned prior art is mainly applied in the grouting field, aiming at rapid filling and curing, and does not address how to construct a controllable porous sound-absorbing structure.

[0008] To address the aforementioned issues, this application provides a self-reinforced sound-absorbing cement-based material, its preparation method, and its mix design method. Summary of the Invention

[0009] To address the deficiencies in the aforementioned technical solutions, the present invention aims to provide a self-reinforced sound-absorbing cement-based material, its preparation method, and its mix design method. This objective is achieved through the following technical solutions:

[0010] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following: 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 75-800 parts functional foam material, 0.019-0.2 parts initiator, and 0.01-0.1 parts accelerator.

[0011] The functional foam material is composed of the following components: composite foaming agent, acrylamide, polyethylene glycol diacrylate, and an appropriate amount of water.

[0012] The mass ratio of the composite foaming agent to acrylamide is 1:5, 1:10, or 1:15.

[0013] The amount of polyethylene glycol diacrylate used is 5%-15% of the mass of acrylamide;

[0014] The composite foaming agent is composed of potassium cocoyl glycinate and sodium dodecyl sulfate.

[0015] The mass ratio of potassium cocoyl glycinate to sodium dodecyl sulfate in the composite foaming agent is 4:1.

[0016] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0017] The composite foam stabilizer consists of 3.6 parts polyacrylamide and 1.2 parts hydroxypropyl methylcellulose ether.

[0018] The initiator is ammonium persulfate.

[0019] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0020] A method for preparing a self-reinforced sound-absorbing cement-based material: In a mortar mixer, 600 parts of cement, 30 parts of expanded perlite, and a composite foam stabilizer are mixed and stirred evenly to form a dry powder. Then, a high-efficiency water-reducing agent is dissolved in 300 parts of water to form a mixing liquid. The mixing liquid is slowly added to the dry powder, and the mixer is turned on and stirred at high speed for 3-5 minutes to form a uniform, lump-free cement slurry. The mixer speed is then reduced to a low speed, and functional foam material is slowly and evenly added to the cement slurry. After mixing for 1 minute, an initial slurry is obtained. Finally, an initiator and an accelerator are added, and the mixture is stirred at high speed for 20 seconds. The mixture is then poured into a mold, covered with a plastic film, and cured under standard conditions for 7 days before demolding to obtain a self-reinforced sound-absorbing cement-based material.

[0021] The preparation method of the functional foam material is as follows: In a clean premix tank equipped with a stirring device, a certain amount of water is added, and stirring is started. Potassium cocoyl glycinate and sodium dodecyl sulfate are added to the water sequentially, and stirred until completely dissolved to form a composite foaming mother liquor. Stirring continues, and metered amounts of acrylamide and polyethylene glycol diacrylate are slowly added to the composite foaming mother liquor; stirring continues until all solid components are completely dissolved, thus preparing a homogeneous functional foam premix. The prepared functional foam premix is ​​then physically foamed using a high-shear foam generator; the air inlet pressure and liquid flow rate of the foaming machine are controlled to prepare a foam with a density between 20-100 kg / m³. 3 A functional foam material with a fine and uniform texture.

[0022] A mix design method for a self-reinforcing sound-absorbing cement-based material includes the following steps:

[0023] Step 1: Using the ratio of composite foaming agent to acrylamide in the foam material and the amount of foam material added to the cement slurry as independent variables, and the porosity of the corresponding molded test block as the dependent variable, construct a first analytical function of the porosity of cement-based sound-absorbing material in relation to the ratio of the amounts of foaming agent and the amount of acrylamide added.

[0024] Step 2: Using the ratio of composite foaming agent to acrylamide in the foam material, the amount of foam material added to the cement slurry, and the curing age of the molded test block as independent variables, and the sound absorption coefficient of the corresponding molded test block at the corresponding curing age as the dependent variable, construct a second analytical function of the sound absorption coefficient of cement-based sound-absorbing material in relation to the ratio of the amount of foaming agent to acrylamide, the amount of foam material added, and the curing age.

[0025] Step 3: Based on the design sound absorption coefficient and design porosity of the cement-based sound-absorbing material to be designed under the design curing age, use the first analysis function and the second analysis function to perform a combined analysis to obtain the ratio of composite foaming agent to acrylamide and the amount of foam material added to the cement slurry for the cement-based sound-absorbing material to be designed to meet the design porosity requirements and the sound absorption coefficient under the design curing age being greater than the lower threshold of the sound absorption coefficient.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. The technical solution of this invention involves adding a prepared functional foam material to a cement slurry, followed by the addition of an initiator and an accelerator; thoroughly mixing and stirring to form a uniform initial slurry; the acrylamide and polyethylene glycol diacrylate in the functional foam material are dispersed in the cement slurry and form a polymer monomer solution on the surface of the foam liquid film; under the exothermic reaction of cement hydration and the action of the initiator, the monomers in the liquid film undergo a polymerization reaction, forming a polymer film on the surface of the pores, thereby constructing a cement-based sound-absorbing material with a closed-pore structure; in the early stage, this polymer film makes the internal pores appear closed. In this state, it acts like a microscopic barrier, locking moisture inside the cement matrix and providing efficient internal curing. It promotes more complete cement hydration, making the material's microstructure denser, thus achieving higher early strength. It also effectively inhibits shrinkage and cracking caused by excessive moisture evaporation and enhances the material's resistance to erosion by harmful external media. Therefore, the material of this invention can be transported to the construction site for assembly immediately after demolding from cement-based sound-absorbing materials. After being manufactured in the factory, it can be installed and put into service on the construction site without long-term curing, reducing factory storage time, significantly accelerating construction efficiency, and improving project progress.

[0028] 2. In the cement-based sound-absorbing material of this application, as the cement hydration reaction continues, the alkaline environment inside the material is continuously enhanced. This polymer membrane responds to this endogenous highly alkaline environment and undergoes slow chemical degradation. As the membrane gradually ruptures and dissolves, the original closed pores are opened and transformed into an interconnected open-pore structure. The pore structure gradually opens, thereby transforming the pores into through pores, which gradually enhances the sound absorption function of the material, ultimately achieving excellent sound absorption effect.

[0029] 3. The technical solution of this application also provides a formula design method based on a mathematical model, which realizes the precise customization of material properties. Through systematic experimental research, a mathematical function relationship between key formula parameters and curing age and the final performance of the material is established. This model-based design method allows R&D personnel to deduce the optimal material formula ratio through calculation and analysis according to specific engineering needs, without having to conduct a large number of blind trial and error experiments. This not only greatly improves R&D efficiency and reduces costs, but more importantly, it realizes the accurate prediction and customized design of sound-absorbing material performance, enabling it to better adapt to diverse application scenarios. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the microscopic cross-section of the self-reinforced sound-absorbing cementitious material prepared in Example 10 of the present invention;

[0031] Figure 2 This is a schematic diagram of the microscopic cross-section of the self-reinforced sound-absorbing cementitious material prepared in Example 11 of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The illustrative embodiments and descriptions of this invention are for explanation only and are not intended to limit the invention. Furthermore, regarding numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0033] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0034] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0035] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0036] In the following examples, "parts" refers to parts by weight.

[0037] Example 1

[0038] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0039] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6.0 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.050 parts initiator, 0.025 parts accelerator, and 200 parts functional foam material;

[0040] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0041] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0042] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0043] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0044] The initiator is ammonium persulfate;

[0045] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0046] The functional foam material is composed of the following components: 4.0 parts of potassium cocoyl glycinate, 1.0 part of sodium dodecyl sulfate, 25.0 parts of acrylamide, 3.75 parts of polyethylene glycol diacrylate, and the balance being water.

[0047] The total amount of the functional foam material is 200 parts by weight, so the remaining water is 166.25 parts by weight.

[0048] The preparation method of the functional foam material is as follows: In a clean premix tank equipped with a stirring device, a certain amount of water is added, and stirring is started. Potassium cocoyl glycinate and sodium dodecyl sulfate are added to the water sequentially, and stirred until completely dissolved to form a composite foaming mother liquor. Stirring continues, and metered acrylamide and polyethylene glycol diacrylate are slowly added to the composite foaming mother liquor; stirring continues until all solid components are completely dissolved, thus preparing a homogeneous, functional foam premix. The prepared functional foam premix is ​​then physically foamed using a high-shear foam generator; the air inlet pressure and liquid flow rate of the foam generator are controlled, i.e., the total weight of the functional foam material, including water, is 200 parts by mass, and the density is between 20-100 kg / m³. 3A functional foam material with a fine and uniform texture.

[0049] A method for preparing a self-reinforced sound-absorbing cement-based material: In a mortar mixer, 600 parts of cement, 30 parts of expanded perlite, and a composite foam stabilizer are mixed and stirred evenly to form a dry powder. Then, a high-efficiency water-reducing agent is dissolved in 300 parts of water to form a mixing liquid. The mixing liquid is slowly added to the dry powder, and the mixer is turned on and stirred at high speed for 3-5 minutes to form a uniform, lump-free cement slurry. The mixer speed is then reduced to a low speed, and functional foam material is slowly and evenly added to the cement slurry. After mixing for 1 minute, an initial slurry is obtained. Finally, an initiator and an accelerator are added and stirred at high speed for 20 seconds to ensure the initiator and accelerator are evenly dispersed in the cement slurry. The mixture is then poured into a mold, covered with a plastic film, and cured for 7 days before demolding to obtain a self-reinforced sound-absorbing cement-based material.

[0050] Example 2

[0051] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following: 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.08 parts initiator, 0.04 parts accelerator, and 320 parts functional foam material.

[0052] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0053] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0054] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0055] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0056] The initiator is ammonium persulfate;

[0057] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0058] The functional foam material is composed of the following components: 6.4 parts potassium cocoyl glycinate, 1.6 parts sodium dodecyl sulfate, 40 parts acrylamide, 6 parts polyethylene glycol diacrylate, and the balance water.

[0059] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 2 are the same as those in Example 1.

[0060] Example 3

[0061] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0062] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.12 parts initiator, 0.06 parts accelerator, and 480 parts functional foam material;

[0063] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0064] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0065] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0066] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0067] The initiator is ammonium persulfate;

[0068] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0069] The functional foam material is composed of the following components: 9.6 parts of potassium cocoyl glycinate, 2.4 parts of sodium dodecyl sulfate, 60 parts of acrylamide, 9 parts of polyethylene glycol diacrylate, and the balance being water.

[0070] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 3 are the same as those in Example 1.

[0071] Example 4

[0072] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0073] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.16 parts initiator, 0.08 parts accelerator, and 640 parts functional foam material;

[0074] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0075] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0076] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0077] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0078] The initiator is ammonium persulfate;

[0079] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0080] The functional foam material is composed of the following components: 12.8 parts of potassium cocoyl glycinate, 3.2 parts of sodium dodecyl sulfate, 80 parts of acrylamide, 12 parts of polyethylene glycol diacrylate, and the balance being water.

[0081] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 4 are the same as those in Example 1.

[0082] Example 5

[0083] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0084] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.2 parts initiator, 0.1 parts accelerator, and 800 parts functional foam material;

[0085] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0086] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0087] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0088] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0089] The initiator is ammonium persulfate;

[0090] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0091] The functional foam material is composed of the following components: 16 parts potassium cocoyl glycinate, 4 parts sodium dodecyl sulfate, 100 parts acrylamide, 15 parts polyethylene glycol diacrylate, and the balance water.

[0092] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 5 are the same as those in Example 1.

[0093] Example 6

[0094] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0095] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.027 parts initiator, 0.014 parts accelerator, and 109.1 parts functional foam material;

[0096] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0097] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0098] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0099] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0100] The initiator is ammonium persulfate;

[0101] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0102] The functional foam material is composed of the following components: 2.2 parts potassium cocoyl glycinate, 0.5 parts sodium dodecyl sulfate, 27.3 parts acrylamide, 2.73 parts polyethylene glycol diacrylate, and the balance water.

[0103] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 6 are the same as those in Example 1.

[0104] Example 7

[0105] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0106] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.044 parts initiator, 0.022 parts accelerator, and 174.5 parts functional foam material;

[0107] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0108] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0109] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0110] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0111] The initiator is ammonium persulfate;

[0112] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0113] The functional foam material is composed of the following components: 3.5 parts potassium cocoyl glycinate, 0.9 parts sodium dodecyl sulfate, 43.6 parts acrylamide, 4.36 parts polyethylene glycol diacrylate, and the balance water.

[0114] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 7 are the same as those in Example 1.

[0115] Example 8

[0116] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0117] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.065 parts initiator, 0.033 parts accelerator, and 261.8 parts functional foam material;

[0118] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0119] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0120] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0121] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0122] The initiator is ammonium persulfate;

[0123] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0124] The functional foam material is composed of the following components: 5.2 parts potassium cocoyl glycinate, 1.3 parts sodium dodecyl sulfate, 65.5 parts acrylamide, 6.55 parts polyethylene glycol diacrylate, and the balance water.

[0125] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 8 are the same as those in Example 1.

[0126] Example 9

[0127] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0128] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.087 parts initiator, 0.044 parts accelerator, and 349.1 parts functional foam material;

[0129] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0130] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0131] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0132] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0133] The initiator is ammonium persulfate;

[0134] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0135] The functional foam material is composed of the following components: 7.0 parts of potassium cocoyl glycinate, 1.7 parts of sodium dodecyl sulfate, 87.3 parts of acrylamide, 8.73 parts of polyethylene glycol diacrylate, and the balance being water.

[0136] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 9 are the same as those in Example 1.

[0137] Example 10

[0138] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0139] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.109 parts initiator, 0.055 parts accelerator, and 436.4 parts functional foam material;

[0140] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0141] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0142] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0143] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0144] The initiator is ammonium persulfate;

[0145] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0146] The functional foam material is composed of the following components: 8.7 parts of potassium cocoyl glycinate, 2.2 parts of sodium dodecyl sulfate, 109.1 parts of acrylamide, 10.91 parts of polyethylene glycol diacrylate, and the balance being water.

[0147] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 10 are the same as those in Example 1.

[0148] Example 11

[0149] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0150] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.019 parts initiator, 0.01 parts accelerator, and 75 parts functional foam material;

[0151] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0152] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0153] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0154] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0155] The initiator is ammonium persulfate;

[0156] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0157] The functional foam material is composed of the following components: 1.5 parts potassium cocoyl glycinate, 0.4 parts sodium dodecyl sulfate, 28.1 parts acrylamide, 1.41 parts polyethylene glycol diacrylate, and the balance water.

[0158] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 11 are the same as those in Example 1.

[0159] Example 12

[0160] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0161] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.03 parts initiator, 0.015 parts accelerator, and 120 parts functional foam material;

[0162] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0163] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0164] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0165] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0166] The initiator is ammonium persulfate;

[0167] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0168] The functional foam material is composed of the following components: 2.4 parts potassium cocoyl glycinate, 0.6 parts sodium dodecyl sulfate, 45 parts acrylamide, 2.25 parts polyethylene glycol diacrylate, and the balance water.

[0169] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 12 are the same as those in Example 1.

[0170] Example 13

[0171] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0172] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.045 parts initiator, 0.023 parts accelerator, and 180 parts functional foam material;

[0173] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0174] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0175] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0176] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0177] The initiator is ammonium persulfate;

[0178] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0179] The functional foam material is composed of the following components: 3.6 parts of potassium cocoyl glycinate, 0.9 parts of sodium dodecyl sulfate, 67.5 parts of acrylamide, 3.38 parts of polyethylene glycol diacrylate, and the balance being water.

[0180] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 13 are the same as those in Example 1.

[0181] Example 14

[0182] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0183] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.06 parts initiator, 0.03 parts accelerator, and 240 parts functional foam material;

[0184] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0185] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0186] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0187] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0188] The initiator is ammonium persulfate;

[0189] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0190] The functional foam material is composed of the following components: 4.8 parts of potassium cocoyl glycinate, 1.2 parts of sodium dodecyl sulfate, 90 parts of acrylamide, 4.5 parts of polyethylene glycol diacrylate, and the balance being water.

[0191] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 14 are the same as those in Example 1.

[0192] Example 15

[0193] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following:

[0194] 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.075 parts initiator, 0.038 parts accelerator, and 300 parts functional foam material;

[0195] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0196] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0197] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0198] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0199] The initiator is ammonium persulfate;

[0200] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0201] The functional foam material is composed of the following components: 6.0 parts of potassium cocoyl glycinate, 1.5 parts of sodium dodecyl sulfate, 112.5 parts of acrylamide, 5.63 parts of polyethylene glycol diacrylate, and the balance being water.

[0202] The preparation methods of the functional foam material and the self-reinforcing sound-absorbing cement-based material in Example 15 are the same as those in Example 1.

[0203] Comparative Example 1

[0204] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following: 600 parts cement, 300 parts water, 30 parts expanded perlite, 6.0 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.045 parts initiator, 0.023 parts accelerator, and 180 parts functional foam material.

[0205] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0206] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0207] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0208] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0209] The initiator is ammonium persulfate;

[0210] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0211] The functional foam material is composed of the following components: 3.6 parts of potassium cocoyl glycinate, 0.9 parts of sodium dodecyl sulfate, 67.5 parts of acrylamide, 3.38 parts of N,N'-methylenebisacrylamide, and the balance being water.

[0212] The difference between Comparative Example 1 and Example 13 is that the polyethylene glycol diacrylate in the functional foam material is replaced by an equal amount of N,N'-methylenebisacrylamide.

[0213] Apart from the above, the other components, their amounts, and preparation methods in Comparative Example 1 are the same as in Example 13.

[0214] Comparative Example 2

[0215] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following: 600 parts cement, 300 parts water, 30 parts expanded perlite, 6.0 parts high-efficiency water-reducing agent, 3.6 parts foam stabilizer, 0.045 parts initiator, 0.023 parts accelerator, and 180 parts functional foam material.

[0216] The foam stabilizer is 3.6 parts of polyacrylamide;

[0217] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0218] The initiator is ammonium persulfate;

[0219] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0220] The functional foam material is composed of the following components: 3.6 parts of potassium cocoyl glycinate, 0.9 parts of sodium dodecyl sulfate, 67.5 parts of acrylamide, 3.38 parts of polyethylene glycol diacrylate, and the balance being water.

[0221] The difference between Comparative Example 2 and Example 13 is that hydroxypropyl methylcellulose ether in the composite foam stabilizer was removed, and only polyacrylamide was retained as the foam stabilizer.

[0222] Apart from the above, the other components, their amounts, and preparation methods in Comparative Example 2 are the same as in Example 13.

[0223] Comparative Example 3

[0224] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following: 600 parts cement, 300 parts water, 30 parts expanded perlite, 6.0 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.045 parts initiator, 0.023 parts accelerator, and 180 parts functional foam material.

[0225] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0226] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0227] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0228] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0229] The initiator is ammonium persulfate;

[0230] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0231] The functional foam material is composed of the following components: 4.5 parts of potassium cocoyl glycinate, 67.5 parts of acrylamide, 3.38 parts of polyethylene glycol diacrylate, and the balance being water.

[0232] The difference between Comparative Example 3 and Example 13 is that sodium dodecyl sulfate was removed from the functional foam material, while the amount of potassium cocoyl glycinate was increased to 4.5 parts.

[0233] Apart from the above, the other components, their amounts, and preparation methods in Comparative Example 3 are the same as in Example 13.

[0234] Comparative Example 4

[0235] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following: 600 parts cement, 300 parts water, 30 parts expanded perlite, 6.0 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.045 parts initiator, 0.023 parts accelerator, and 180 parts functional foam material.

[0236] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0237] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0238] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0239] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0240] The initiator is ammonium persulfate;

[0241] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0242] The functional foam material is composed of the following components: 3.6 parts of potassium cocoyl glycinate, 0.9 parts of sodium dodecyl sulfate, 67.5 parts of acrylamide, 20.25 parts of polyethylene glycol diacrylate, and the balance being water.

[0243] The difference between Comparative Example 4 and Example 13 is that the amount of polyethylene glycol diacrylate in the functional foam material is increased to 30% of the mass of acrylamide;

[0244] Apart from the above, the other components, their amounts, and preparation methods in Comparative Example 4 are the same as in Example 13.

[0245] Comparative Example 5

[0246] A self-reinforcing sound-absorbing cement-based material, by weight, comprises the following: 600 parts cement, 300 parts water, 30 parts expanded perlite, 6.0 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 0.045 parts initiator, 0.023 parts accelerator, and 180 parts functional foam material.

[0247] The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether;

[0248] The foam stabilizer consists of 3.6 parts of polyacrylamide;

[0249] The hydroxypropyl methylcellulose ether is 1.2 parts;

[0250] The high-efficiency water-reducing agent is a polycarboxylate water-reducing agent;

[0251] The initiator is ammonium persulfate;

[0252] The accelerator is N,N,N',N'-tetramethylethylenediamine.

[0253] The functional foam material is composed of the following components: 3.6 parts potassium cocoyl glycinate, 0.9 parts sodium dodecyl sulfate, 67.5 parts acrylamide, 1.35 parts polyethylene glycol diacrylate, and the balance water.

[0254] The difference between Comparative Example 5 and Example 13 is that the amount of polyethylene glycol diacrylate in the functional foam material is increased to 2% of the mass of acrylamide;

[0255] Apart from the above, the other components, their amounts, and preparation methods in Comparative Example 5 are the same as in Example 13.

[0256] Test case

[0257] Refer to the relevant test provisions in GB / T 43487-2023 "Test Methods for Foamed Concrete and Products" to complete the test of porosity of the test blocks;

[0258] Referring to GB / T 18696.1 "Measurement of sound absorption and impedance in acoustic impedance tubes", the sound absorption coefficients of the test block at 7d, 14d, and 28d were tested.

[0259] The test results for Examples 1-15 are shown in Table 1 below:

[0260] Table 1

[0261]

[0262] As shown in Table 1, the technical solutions of embodiments 1-15 of this application can gradually enhance the sound absorption function of the material over time, ultimately achieving excellent sound absorption effect.

[0263] Among them, such as Figure 1 The image shown is a schematic microscopic cross-section of the self-reinforced sound-absorbing cementitious material prepared in Example 10; as shown... Figure 2 The image shows a schematic microscopic cross-section of the self-reinforced sound-absorbing cementitious material prepared in Example 11.

[0264] The test results for Comparative Examples 1-5 are shown in Table 2:

[0265] Table 2

[0266]

[0267] As shown in Comparative Example 1, when the polyethylene glycol diacrylate in the functional foam material of this invention was replaced with N,N'-methylenebisacrylamide, although its early sound absorption coefficient was comparable to that of Example 13, its later sound absorption coefficient hardly increased; while the 28-day sound absorption coefficients of the embodiments of this application all significantly increased to over 0.69. Comparative Example 2 removed hydroxypropyl methylcellulose ether from the foam stabilizer. In Comparative Example 2, lacking the synergistic effect of the composite foam stabilizer system, its pore structure quality and final sound absorption performance significantly decreased. Comparative Example 3 removed sodium dodecyl sulfate; this indicates that without the assistance of this foaming agent, a large number of foams may break down, resulting in a serious failure to meet the standards for final porosity and 28-day sound absorption coefficient. The above Comparative Examples 1, 2, and 3 illustrate that the technical solution of this application is a systematic solution obtained through extensive experimental exploration and optimization; it is not a conventional choice, but rather an indispensable creative effort to ensure the realization of this invention.

[0268] In Comparative Example 4, the amount of polyethylene glycol diacrylate (PEG) in the foam material was too high, reaching 30%, while in Comparative Example 5, the amount was too low, at 2%. The excessively low PEG diacrylate content resulted in insufficient early-stage membrane strength, failing to effectively support the pore structure, leading to mold collapse and ultimately poor performance. In Comparative Example 4, while the excessive PEG diacrylate content ensured the early structure, the resulting dense network severely hindered subsequent alkaline hydrolytic degradation, causing almost complete loss of the self-reinforcing properties.

[0269] A mix design method for a self-reinforcing sound-absorbing cement-based material includes the following steps:

[0270] Step 1: Using the ratio of composite foaming agent to acrylamide in the foam material and the amount of foam material added to the cement slurry as independent variables, and the porosity of the corresponding molded test block as the dependent variable, construct a first analytical function of the porosity of cement-based sound-absorbing material in relation to the ratio of the amounts of foaming agent and the amount of acrylamide added.

[0271] Specifically, based on the data obtained in Examples 1-15 of this application, a first analytical function for porosity is obtained by fitting a quadratic polynomial regression. ,in The porosity of cement-based sound-absorbing materials. This refers to the mass ratio of composite foaming agent to acrylamide in the foam material. This is the ratio of the amount of foam material added to the amount of cementitious material used.

[0272] Step 2: Using the ratio of composite foaming agent to acrylamide in the foam material, the amount of foam material added to the cement slurry, and the curing age of the molded test block as independent variables, and the sound absorption coefficient of the corresponding molded test block at the corresponding curing age as the dependent variable, construct a second analytical function for the sound absorption coefficient of cement-based sound-absorbing material in relation to the ratio of the amount of foaming agent to acrylamide, the amount of foam material added, and the curing age.

[0273] Specifically, based on the data obtained in Examples 1-15 of this application, the sound absorption coefficient exhibits a non-linear relationship with the mass ratio of foam material and the proportion of foam material added. Furthermore, as the curing time increases, the increase in the sound absorption coefficient first increases and then tends to level off. The fitted second analytical function... ,in is the sound absorption coefficient of cement-based sound-absorbing materials, and is the mass ratio of amino acids to acrylamide in the foam material. This refers to the ratio of the amount of foam material added to the amount of cementitious material used. The maintenance period is measured in days.

[0274] Step 3: Based on the design sound absorption coefficient and design porosity of the cement-based sound-absorbing material to be designed under the design curing age, use the first analysis function and the second analysis function to perform a combined analysis to obtain the ratio of composite foaming agent to acrylamide and the amount of foam material added to the cement slurry for the cement-based sound-absorbing material to be designed to meet the design porosity requirements and the sound absorption coefficient under the design curing age being greater than the lower threshold of the sound absorption coefficient.

[0275] In practical applications: if a porosity of 0.5 (i.e., a bulk density of 500 kg / m³) is required... 3 After 14 days of curing, the sound absorption coefficient reached 0.36. Under the same cementitious material and dosage, the water-cement ratio was 0.5. The mass ratio of composite foaming agent to acrylamide in the foam material was obtained by simultaneously solving the first and second analytical functions. The ratio of foam material added to cementitious material is 0.17. The value is 0.11; therefore, it can be predicted that the sound absorption coefficient may increase to 0.73 after 28 days of maintenance.

[0276] Furthermore, in accordance with the engineering design requirements, the lower threshold values ​​of the sound absorption coefficient of the cement-based sound-absorbing material under the preset curing conditions and the designed curing age include: 0.1 for a 7-day curing age, 0.35 for a 14-day curing age, and 0.68 for a 28-day curing age.

[0277] The technical solution of this application also provides a mix design method, which realizes the precise customization of material properties. This allows R&D personnel to deduce the optimal material mix ratio through calculation and analysis based on specific engineering needs, without having to conduct a large number of blind trial and error experiments. This not only greatly improves R&D efficiency and reduces costs, but more importantly, it enables the accurate prediction and customized design of sound-absorbing material performance, making it better adaptable to diverse application scenarios.

[0278] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A self-reinforcing sound-absorbing cement-based material, comprising, by weight, the following: 600 parts cement, 300 parts water, 30 parts expanded perlite, 6 parts high-efficiency water-reducing agent, 4.8 parts composite foam stabilizer, 75-800 parts functional foam material, 0.019-0.2 parts initiator, and 0.01-0.1 parts accelerator; The functional foam material is composed of the following components: composite foaming agent, acrylamide, polyethylene glycol diacrylate, and water; The mass ratio of the composite foaming agent to acrylamide is any one of 1:5, 1:10, or 1:

15. The amount of polyethylene glycol diacrylate used is 5%-15% of the mass of acrylamide; The composite foaming agent is composed of potassium cocoyl glycinate and sodium dodecyl sulfate.

2. The self-reinforcing sound-absorbing cement-based material according to claim 1, characterized in that, The foam stabilizer is composed of polyacrylamide and hydroxypropyl methylcellulose ether; the composite foam stabilizer is composed of 3.6 parts polyacrylamide and 1.2 parts hydroxypropyl methylcellulose ether.

3. The self-reinforcing sound-absorbing cement-based material according to claim 1, characterized in that, The mass ratio of potassium cocoyl glycinate to sodium dodecyl sulfate in the composite foaming agent is 4:

1.

4. The self-reinforcing sound-absorbing cement-based material according to claim 1, characterized in that, The initiator is ammonium persulfate.

5. The self-reinforcing sound-absorbing cement-based material according to claim 1, characterized in that, The accelerator is N,N,N',N'-tetramethylethylenediamine.

6. A method for preparing a self-reinforced sound-absorbing cementitious material according to any one of claims 1-5, characterized in that, The preparation method is as follows: cement, expanded perlite, and composite foam stabilizer are mixed in a mixer and stirred evenly to form a dry powder. The high-efficiency water-reducing agent is then dissolved in water to form a mixing liquid. The mixing liquid is slowly added to the dry powder, and the mixer is turned on and stirred at high speed for 3-5 minutes to form a uniform, lump-free cement slurry. The mixer speed is then reduced to low speed, and the functional foam material is slowly and evenly added to the cement slurry. After mixing for 1 minute, the initial slurry is obtained. Finally, the initiator and accelerator are added, and the mixture is stirred at high speed for 20 seconds. The mixture is then poured into a mold, and the mold is covered with a plastic film. After standard curing for 7 days, the material is demolded to obtain a self-reinforced sound-absorbing cement-based material.

7. The method for preparing a self-reinforced sound-absorbing cementitious material according to claim 6, characterized in that, The preparation method of the functional foam material is as follows: In a premixing tank equipped with a stirring device, water is added and stirring is started. Potassium cocoyl glycinate and sodium dodecyl sulfate are added to the water in sequence and stirred until completely dissolved to form a composite foaming mother liquor. Stirring is continued, and acrylamide and polyethylene glycol diacrylate are slowly added to the composite foaming mother liquor. Stirring is continued until all solid components are completely dissolved, thus preparing a uniform functional foam premix. The prepared functional foam premix is ​​then physically foamed through a high-shear foam generator. The air inlet pressure and liquid flow rate of the foaming machine are controlled to prepare the functional foam material.

8. The mix design method for a self-reinforcing sound-absorbing cementitious material according to any one of claims 1-5, characterized in that, The mix design method includes the following steps: Step 1: Using the ratio of composite foaming agent to acrylamide in the foam material and the amount of foam material added to the cement slurry as independent variables, and the porosity of the corresponding molded test block as the dependent variable, construct a first analytical function of the porosity of cement-based sound-absorbing material in relation to the ratio of the amounts of foaming agent and the amount of acrylamide added. Step 2: Using the ratio of composite foaming agent to acrylamide in the foam material, the amount of foam material added to the cement slurry, and the curing age of the molded test block as independent variables, and the sound absorption coefficient of the corresponding molded test block at the corresponding curing age as the dependent variable, construct a second analytical function of the sound absorption coefficient of cement-based sound-absorbing material in relation to the ratio of the amount of foaming agent to acrylamide, the amount of foam material added, and the curing age. Step 3: Based on the design sound absorption coefficient and design porosity of the cement-based sound-absorbing material to be designed under the design curing age, use the first analysis function and the second analysis function to perform a combined analysis to obtain the ratio of composite foaming agent to acrylamide and the amount of foam material added to the cement slurry for the cement-based sound-absorbing material to be designed to meet the design porosity requirements and the sound absorption coefficient under the design curing age being greater than the lower threshold of the sound absorption coefficient.

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