An on-off aperture control type electromagnetic shielding concrete

Abstract

This invention relates to an open-closed-cell controlled electromagnetic shielding concrete, which is a foamed concrete. Its formula includes a foam stabilizer and a foaming agent, with the foam stabilizer accounting for 35-72% of the foaming agent's mass. The foamed concrete has both open-cell and closed-cell structures. The foam stabilizer includes a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), a nonionic surfactant, Triton X-100 (TX-100), a nonionic surfactant, Tween 60 (T60), and an anionic surfactant, sodium dodecyl sulfate (SDS). By adjusting the ratio of CTAB, Triton X-100, SDS, and Tween 60, the open-cell ratio of the open-closed-cell controlled electromagnetic shielding concrete is controlled, thereby regulating the electromagnetic wave reflection loss and achieving free adjustment of the reflection loss for specific electromagnetic wave bands.

Description

Technical Field

[0001] This invention belongs to the technical field of novel building electromagnetic protection materials, specifically an open-closed pore controlled electromagnetic protection concrete. Background Technology

[0002] With the widespread application of electromagnetic wave technology, a new wave of pollution has emerged: electronic devices may leak private information or be affected by other electromagnetic interference during operation. Whether electromagnetic waves will harm the living environment and human health has always been a topic of great concern. Therefore, research on electromagnetic absorption or electromagnetic shielding technology is indispensable. Compared with commonly used coating-based microwave absorbing materials, cement-based microwave absorbing materials can avoid the disadvantages of easy oxidation and peeling, and poor durability. Using carbon black, carbon fiber, and carbon nanotubes as absorbents can further enhance the electromagnetic wave absorption performance of concrete. Similar to porous materials such as EPS, EP, GP, and hollow glass microspheres (HGM), the pore structure in foamed cement-based materials can also improve impedance matching performance and electromagnetic wave loss capability. However, the pore structure of existing foamed cement-based materials is generally uncontrollable, resulting in poor absorption effect on electromagnetic waves. Therefore, this application proposes a novel electromagnetic protection concrete that controls the internal microstructure of cement-based materials, making the preparation process simple, reducing costs, and achieving effective absorption loss for specific wavebands through reasonable open-closed pore structure design, while also meeting good strength requirements. Summary of the Invention

[0003] Based on modern electromagnetic protection requirements, this invention provides an open-closed-pore controlled electromagnetic protection concrete. By adjusting the open-pore ratio of the foamed concrete, the reflection loss of electromagnetic waves in a specific frequency band can be freely adjusted within the range of 1 to 18 GHz.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] An open-cell / closed-cell controlled electromagnetic shielding concrete is a foamed concrete. Its formula includes a foam stabilizer and a foaming agent, with the foam stabilizer accounting for 35-72% of the foaming agent's mass. The foamed concrete has both open-cell and closed-cell structures. The foam stabilizer includes the cationic surfactant cetyltrimethylammonium bromide (CTAB), the nonionic surfactant Triton X-100 (TX-100), the nonionic surfactant Tween 60 (T60), and the anionic surfactant sodium dodecyl sulfate (SDS).

[0006] The porosity of open-cell controlled electromagnetic shielding concrete is controlled by adjusting the ratio of hexadecyltrimethylammonium bromide (CTAB), Triton X-100, sodium dodecyl sulfate (SDS), and Tween 60, thereby regulating the electromagnetic wave reflection loss of the open-cell controlled electromagnetic shielding concrete and achieving free adjustment of the reflection loss of electromagnetic waves in a specific band.

[0007] Furthermore, the cationic surfactant is used to form an open-cell structure;

[0008] Anionic surfactants are used to form closed-cell structures;

[0009] The nonionic surfactant is used to reduce the total amount of surfactant used and improve the stability of the foam. TX-100 is used to control the stability of CTAB, and T60 is used to control the stability of SDS.

[0010] The mass of TX-100 is 160%-200% of the mass of CTAB, and the mass of T60 is 20%-25% of the mass of SDS.

[0011] The porosity of open-closed-pore controlled electromagnetic protective concrete can be adjusted by regulating the ratio of CTAB and SDS.

[0012] Furthermore, the composition of the open-closed pore controlled electromagnetic protective concrete includes ordinary Portland cement, fly ash, slag powder, foaming agent, foam stabilizer, water-reducing agent, accelerator, and water. The mass ratio of fly ash, ordinary Portland cement, and slag powder is: fly ash: ordinary Portland cement: slag powder = 2:3:1; the mass of the foaming agent is 4-11% of the mass of water; the specific preparation process is as follows:

[0013] Ordinary silicate cement, fly ash, and slag powder are uniformly mixed to obtain a dry mixture;

[0014] While stirring at 80-100 rpm / min, water is added to the dry mixture to form a viscous gel; the mass ratio of water to dry mixture is 0.5-0.55:1.

[0015] Next, add the water-reducing agent and quick-setting agent in sequence, and start stirring at a speed of 280-350 rpm / min until it becomes a uniform and flowable mixture.

[0016] Finally, the foaming agent is added to the mixture slurry, and the foam stabilizer is added. The mixture is stirred at a speed of 280-350 pm / min to obtain open-closed pore controlled electromagnetic protective concrete.

[0017] The foam stabilizer is incorporated as follows: four types of foam stabilizers are mixed and stirred thoroughly to ensure the uniformity of the mixture. Then, the mixed foam stabilizer is gradually injected into the cement paste, and stirring is continued during the injection process to ensure uniform distribution. This prevents local concentration or uneven distribution of the foam stabilizer in the concrete, thereby ensuring the performance and quality of the concrete.

[0018] Furthermore, the water-reducing agent is at least one of naphthalene-based high-efficiency water-reducing agent, aliphatic high-efficiency water-reducing agent, amino high-efficiency water-reducing agent, and polycarboxylate high-performance water-reducing agent, and the amount added is 1 to 2% of the mass of water;

[0019] The quick-setting agent is an alkali-free quick-setting agent with aluminum sulfate as the main component. The mass of the quick-setting agent is 3 to 4% of the mass of water, which enables the mixed slurry to solidify and harden immediately after foaming, while maintaining good fluidity of the mixed slurry before and during foaming.

[0020] The foaming agent is hydrogen peroxide or plant protein.

[0021] Furthermore, by adding foaming agents of varying masses, foams with densities ranging from 400 to 1200 kg / m³ are produced. 3 With the addition of foaming agent, the density of foamed concrete gradually decreases, while the porosity gradually increases within the range of 37% to 72%. As the density increases, the effective absorption loss peak first increases and then decreases, thus achieving electromagnetic absorption loss control at different peak values ​​in specific wavebands.

[0022] Furthermore, the specific rules for freely adjusting the reflection loss of electromagnetic waves in a specific band are as follows:

[0023] When the effective absorption band of the target is 1.0 to 5.0 GHz, the corresponding porosity of the open-closed pore controlled electromagnetic shielding concrete is 4%.

[0024] When the effective absorption band of the target is 5.0 to 11.0 GHz, the corresponding porosity of the open-closed pore controlled electromagnetic shielding concrete is 30%.

[0025] When the effective absorption band of the target is 11.0 to 14.0 GHz, the porosity of the open-closed pore controlled electromagnetic shielding concrete is 77%.

[0026] When the effective absorption band of the target is 14.0 to 18.0 GHz, the porosity of the open-closed pore controlled electromagnetic shielding concrete is 98%.

[0027] The effective absorption band and its corresponding aperture ratio are represented by data points in the form of (initial value of band, aperture ratio). For any given effective absorption band, if it is not within the above range, or if it overlaps with the above range, the aperture ratio of any given absorption band is calculated by linear interpolation. The specific process is as follows:

[0028] Using any given effective absorption band as the target band, for the target band, find the two known data points that are closest to the initial value of the target band, and use a linear interpolation formula to calculate the aperture ratio corresponding to the target band. The specific calculation method is as follows:

[0029] Let the known data points approaching the target band be (f1, r1) and (f2, r2), where (f1) and (f2) represent the initial values ​​of the band, and (r1) and (r2) represent the corresponding aperture ratios; for the initial value of the target band (f1, r1) and (f2), the data points approaching the target band are (f1, r1) and (f2, r2), respectively. t The corresponding aperture ratio (r) is calculated using a linear interpolation formula. t )for:

[0030] r t =r1+(f t -f1) / (r2-r1)×(f2-f1).

[0031] The porosity of open-closed-pore controlled electromagnetic shielding concrete is controlled by adjusting the ratio of hexadecyltrimethylammonium bromide (CTAB), Triton X-100, sodium dodecyl sulfate (SDS), and Tween 60. The specific process is as follows:

[0032] By setting the mass ratio of SDS to CTAB to 5:0, open-closed pore controlled electromagnetic protective concrete with an opening rate of 1% to 25% was obtained.

[0033] By setting the mass ratio of SDS to CTAB to 15:1, open-closed pore controlled electromagnetic protective concrete with an opening rate of 26% to 50% was obtained.

[0034] By setting the mass ratio of SDS to CTAB to 10:3, open-closed pore controlled electromagnetic protective concrete with an opening rate of 51% to 79% was obtained.

[0035] By setting the mass ratio of SDS to CTAB to 0:4, open-closed pore controlled electromagnetic protective concrete with an opening rate of 80% to 99% was obtained.

[0036] The mass of TX-100 is 160%-200% of the mass of CTAB, and the mass of T60 is 20%-25% of the mass of SDS.

[0037] The foam stabilizer accounts for 72% of the foaming agent mass, corresponding to an open-closed cell controlled electromagnetic protective concrete with an open cell ratio of 4%.

[0038] The foam stabilizer accounts for 58% of the foaming agent mass, corresponding to an open-closed cell controlled electromagnetic protective concrete with an open-cell ratio of 30%.

[0039] The foam stabilizer accounts for 47% of the foaming agent mass, corresponding to an open-closed cell controlled electromagnetic protective concrete with an open-cell ratio of 77%.

[0040] The foam stabilizer accounts for 35% of the foaming agent mass, corresponding to an open-closed cell controlled electromagnetic protective concrete with an open-cell rate of 98%.

[0041] The mass ratio of SDS to CTAB is determined based on the opening ratio corresponding to the target wavelength. Then, based on the opening ratio corresponding to the target wavelength, the percentage of foam stabilizer in the mass of foaming agent is determined by linear interpolation.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] This invention relates to open-closed-hole controlled electromagnetic shielding concrete, with an electromagnetic absorbing matrix having a density of 400–1200 kg / m³. 3 Foamed concrete, by controlling its open-cell ratio, achieves effective absorption loss for specific wavelengths. As the open-cell ratio increases, the material's effective electromagnetic wave absorption loss gradually changes from low-wavelength to high-wavelength electromagnetic wave absorption loss.

[0044] In this invention, the porosity is controlled by adjusting the proportions of the added cationic surfactant cetyltrimethylammonium bromide (CTAB), nonionic surfactant Triton X-100 (TX-100), anionic surfactant sodium dodecyl sulfate (SDS), and nonionic surfactant Tween 60 (T60). The average reflection loss rate of electromagnetic waves in the 1–18 Hz band can reach below -20 dB, exhibiting ideal absorption loss effect and broad application prospects. Attached Figure Description

[0045] Figure 1 This is a schematic diagram illustrating the transmission mode of electromagnetic waves in porous materials in the open-closed pore controlled electromagnetic protective concrete of the present invention.

[0046] Figure 2 This is a schematic diagram illustrating the transmission mode of electromagnetic waves in the pore unit of the open-closed pore controlled electromagnetic protective concrete of the present invention. Detailed Implementation

[0047] 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. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0048] This invention discloses an open-closed-cell controlled electromagnetic shielding concrete. It utilizes ordinary silicate cement, fly ash, and slag powder, which are uniformly mixed to obtain a dry mixture. Water is then added to the dry mixture while stirring at low speed, forming a viscous gel. Next, a water-reducing agent and a quick-setting agent are added sequentially, followed by high-speed stirring until a uniform and flowable slurry is formed. Finally, a foaming agent is rapidly added to the slurry, along with a foam stabilizer, and high-speed stirring continues to yield the open-closed-cell controlled electromagnetic shielding concrete. The fly ash:ordinary silicate cement:slag powder ratio is 2:3:1; the water-to-mixture mass ratio is 0.5–0.55:1; the foam stabilizer accounts for 35–72% of the foaming agent's mass; and the foaming agent accounts for 4–11% of the water's mass.

[0049] Using one of the following high-efficiency water-reducing agents—naphthalene-based, aliphatic, amino, or polycarboxylate—at a rate of 1-2% of the water mass, can meet the requirement of minimizing the water-cement ratio of the cement paste in practical engineering while maintaining good fluidity, making it easy for foam to be generated and evenly distributed in the newly poured foamed concrete matrix. Using 3-4% of an alkali-free quick-setting agent with aluminum oxide as the main component, at a rate of 3-4% of the water mass, can shorten the setting time in practical engineering, allowing the slurry to set and harden immediately after foaming, while maintaining good fluidity before and during foaming.

[0050] By adding different amounts of foaming agent, foams with densities ranging from 400 to 1200 kg / m³ can be produced. 3 The foamed concrete has a foaming agent content of 4% to 11% of the water mass. As the foaming agent is added, the density of the foamed concrete gradually decreases, and the porosity gradually increases in the range of 37% to 72%. As the density increases, the effective absorption loss peak first increases and then decreases, thus achieving electromagnetic absorption loss of different peak values ​​in a specific waveband.

[0051] The selected foam stabilizers include different combinations of the cationic surfactant cetyltrimethylammonium bromide (CTAB), the nonionic surfactant Triton X-100 (TX-100), the anionic surfactant sodium dodecyl sulfate (SDS), and the nonionic surfactant Tween 60 (T60). These different types of surfactants each have specific functions: cationic surfactants help form open-cell structures, while anionic surfactants are more conducive to forming closed-cell structures, and nonionic surfactants help reduce the total amount of surfactant used and improve foam stability. Furthermore, in the preparation of open-closed-cell controlled electromagnetic shielding concrete, the consumption of the anionic surfactant SDS is higher than that of the cationic surfactant CTAB. Meanwhile, TX-100 is used to control the stability of CTAB, and T60 is used to control the stability of SDS. The mass of TX-100 is 160%-200% of the mass of CTAB, and the mass of T60 is 20%-25% of the mass of SDS. The open-cell ratio of the open-closed-cell controlled electromagnetic shielding concrete is adjusted by regulating the ratio of CTAB to SDS.

[0052] The foam stabilizer addition method for open-closed pore controlled electromagnetic shielding concrete in this invention is as follows: First, four types of foam stabilizers are mixed, and the mixture is thoroughly stirred to ensure homogeneity. Then, the mixed foam stabilizer is slowly injected into the cement paste, with continuous stirring during the injection process to ensure uniform distribution. The importance of this key method lies in ensuring the foam stabilizer is injected uniformly, preventing localized concentration or uneven distribution of the foam stabilizer in the concrete, thereby guaranteeing the performance and quality of the concrete.

[0053] The absorption mechanism of open-closed pore controlled electromagnetic shielding concrete is as follows: the presence of the pore structure increases the impedance matching between the composite material and free space, making it easier for electromagnetic waves to enter the composite material; in open-closed pore controlled electromagnetic shielding concrete, electromagnetic waves undergo multiple reflections, scattering and interference losses in the pores. When there are more pores, the propagation mode of electromagnetic waves becomes more complex and the interference loss increases.

[0054] In this invention, closed pore refers to the existence of a single pore; open pore refers to at least two pores connected together; and the open pore ratio refers to the proportion of open pores in electromagnetic protective concrete.

[0055] The low speed mentioned above is 80-100 rpm / min, and the high speed is 280-350 rpm / min; the foaming agent is hydrogen peroxide or plant protein, etc., preferably hydrogen peroxide.

[0056] For open-closed-pore controlled electromagnetic shielding concrete, specific waveband electromagnetic wave design is performed, and materials with different open pore ratios are selected according to the following rules:

[0057] When the effective absorption band of the target is 1.0 to 5.0 GHz, the corresponding porosity of the open-closed pore controlled electromagnetic shielding concrete is 4%.

[0058] When the effective absorption band of the target is 5.0 to 11.0 GHz, the corresponding porosity of the open-closed pore controlled electromagnetic shielding concrete is 30%.

[0059] When the effective absorption band of the target is 11.0 to 14.0 GHz, the porosity of the open-closed pore controlled electromagnetic shielding concrete is 77%.

[0060] When the effective absorption band of the target is 14.0 to 18.0 GHz, the porosity of the open-closed pore controlled electromagnetic shielding concrete is 98%.

[0061] To calculate the aperture ratio of any absorption band, a linear interpolation method was used. The effective absorption band and its corresponding aperture ratio were represented as data points in the form of (initial band value, aperture ratio). For any given effective absorption band, if it is not within the above range, or if it overlaps with the above range, the aperture ratio of that given absorption band was calculated using linear interpolation. The specific process is as follows:

[0062] Let the known data points close to the target band be (f1, r1) and (f2, r2), where (f1) and (f2) represent the initial values ​​of the band (i.e., the left endpoints of the interval), and (r1) and (r2) represent the corresponding aperture ratios. For the initial value of the target band (f... t The corresponding aperture ratio (r) is calculated using a linear interpolation formula. t )as follows:

[0063] r t =r1+(f t -f1) / (r2-r1)×(f2-f1)

[0064] This method allows for the calculation of aperture ratio for any wavelength band.

[0065] After determining the open area ratio, the next step is to determine the type and amount of foam stabilizer to be added. The specific process is as follows:

[0066] By setting the mass ratio of SDS to CTAB to 5:0, open-closed pore controlled electromagnetic protective concrete with an opening rate of 1% to 25% was obtained.

[0067] By setting the mass ratio of SDS to CTAB to 15:1, open-closed pore controlled electromagnetic protective concrete with an opening rate of 26% to 50% was obtained.

[0068] By setting the mass ratio of SDS to CTAB to 10:3, open-closed pore controlled electromagnetic protective concrete with an opening rate of 51% to 79% was obtained.

[0069] By setting the mass ratio of SDS to CTAB to 0:4, open-closed pore controlled electromagnetic protective concrete with an opening rate of 80% to 99% was obtained.

[0070] The mass of TX-100 is 160%-200% of the mass of CTAB, and the mass of T60 is 20%-25% of the mass of SDS.

[0071] The foam stabilizer accounts for 72% of the foaming agent mass, corresponding to an open-closed cell controlled electromagnetic protective concrete with an open cell ratio of 4%.

[0072] The foam stabilizer accounts for 58% of the foaming agent mass, corresponding to an open-closed cell controlled electromagnetic protective concrete with an open-cell ratio of 30%.

[0073] The foam stabilizer accounts for 47% of the foaming agent mass, corresponding to an open-closed cell controlled electromagnetic protective concrete with an open-cell ratio of 77%.

[0074] The foam stabilizer accounts for 35% of the foaming agent mass, corresponding to an open-closed cell controlled electromagnetic protective concrete with an open-cell rate of 98%.

[0075] Based on the porosity corresponding to the target waveband determined above, and combined with the above rules, the mass ratio of SDS and CTAB, as well as the range and amount of nonionic surfactant added, are determined. Then, based on the porosity corresponding to the target waveband, the percentage of foam stabilizer in the mass of foaming agent is determined by linear interpolation, thereby determining the formula of open-closed pore controlled electromagnetic protective concrete that meets the requirements of the target waveband.

[0076] Example 1

[0077] Ordinary silicate cement, fly ash, and slag powder are uniformly mixed in a specific ratio to obtain a dry mixture. Water is then added to the dry mixture while stirring at low speed to form a viscous gel. Next, a water-reducing agent and a quick-setting agent are added sequentially, followed by high-speed stirring until a uniform and flowable slurry is formed. Then, a foaming agent, hydrogen peroxide, is rapidly added to the slurry mixture. Following this, four foam stabilizers are mixed in a predetermined ratio, and thorough stirring ensures the homogeneity of the mixture. Subsequently, the mixed foam stabilizer is slowly injected into the cement slurry, with continuous stirring during the injection process to ensure uniform distribution, resulting in open- and closed-cell controlled electromagnetic shielding concrete. The specific proportions are shown in Table 1 below (the mass of the foam stabilizer is based on the mass of the foaming agent; in Table 1, SDS, T60, CTAB, and TX-100 represent their respective mass percentages of the foam stabilizer).

[0078] Table 1. Mix proportions (parts by weight) of open-closed-hole controlled electromagnetic shielding concrete in Example 1.

[0079]

[0080] Table 2 Test results of open-closed-hole controlled electromagnetic shielding concrete in Example 1

[0081]

[0082] As shown in Table 2, the open-closed-cell controlled electromagnetic shielding concrete achieves effective absorption loss for specific wavebands by controlling the open-cell ratio of the foamed concrete. With increasing open-cell ratio, the material's effective absorption loss for low-band electromagnetic waves gradually changes to its effective absorption loss for high-band electromagnetic waves.

[0083] Example 2

[0084] Ordinary silicate cement was replaced with ordinary phosphate cement, and the remaining steps and proportions were carried out in accordance with Example 1 and Table 1. The following results were obtained after testing.

[0085] Table 3. Test results of open-closed-hole controlled electromagnetic shielding concrete in Example 2

[0086]

[0087] As can be seen from Table 3, the present invention is applicable to any concrete matrix material. By controlling the porosity of foamed concrete, it can effectively absorb and reduce electromagnetic waves in specific bands.

[0088] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. An open-closed-hole controlled electromagnetic shielding concrete, characterized in that, The open-closed-cell controlled electromagnetic protection concrete is foamed concrete, and its formula includes a foam stabilizer and a foaming agent. The mass of the foam stabilizer is 35-72% of the mass of the foaming agent. The foamed concrete has an open-cell structure and a closed-cell structure. The foam stabilizer includes cetyltrimethylammonium bromide (CTAB), TX-100, Tween T60, and sodium dodecyl sulfate (SDS). The mass of TX-100 is 160%-200% of the mass of cetyltrimethylammonium bromide (CTAB), and the mass of Tween T60 is 20%-25% of the mass of sodium dodecyl sulfate (SDS). The porosity of open-cell controlled electromagnetic shielding concrete is controlled by adjusting the ratio of hexadecyltrimethylammonium bromide (CTAB), TX-100, sodium dodecyl sulfate (SDS), and Tween T60. This allows for the regulation of electromagnetic wave reflection loss in the open-cell controlled electromagnetic shielding concrete, thus enabling free adjustment of the reflection loss of electromagnetic waves in specific bands.

2. The open-closed-hole controlled electromagnetic protective concrete according to claim 1, characterized in that, Hexadecyltrimethylammonium bromide (CTAB) is used to form open-cell structures; Sodium dodecyl sulfate (SDS) is used to form closed-cell structures; TX-100 is used to control the stability of cetyltrimethylammonium bromide (CTAB), and Tween T60 is used to control the stability of sodium dodecyl sulfate (SDS). The porosity of open-closed-pore controlled electromagnetic shielding concrete can be adjusted by regulating the ratio of hexadecyltrimethylammonium bromide (CTAB) to sodium dodecyl sulfate (SDS).

3. The open-closed-hole controlled electromagnetic protective concrete according to claim 1, characterized in that, The open-closed-pore controlled electromagnetic shielding concrete comprises ordinary Portland cement, fly ash, slag powder, foaming agent, foam stabilizer, water-reducing agent, accelerator, and water. The mass ratio of fly ash, ordinary Portland cement, and slag powder is: fly ash: ordinary Portland cement: slag powder = 2:3:1; the mass of the foaming agent is 4-11% of the mass of water; the specific preparation process is as follows: Ordinary silicate cement, fly ash, and slag powder are uniformly mixed to obtain a dry mixture; While stirring at 80-100 rpm / min, water is added to the dry mixture to form a viscous gel; the mass ratio of water to dry mixture is 0.5~0.55:

1. Next, add the water-reducing agent and quick-setting agent in sequence, and start stirring at a speed of 280-350 rpm / min until it becomes a uniform and flowable slurry. Finally, the foaming agent is added to the mixture slurry, and the foam stabilizer is added. The mixture is stirred at a speed of 280-350 pm / min to obtain open-closed pore controlled electromagnetic protective concrete. The foam stabilizer is incorporated as follows: four types of foam stabilizers are mixed and stirred thoroughly to ensure the uniformity of the mixture. Then, the mixed foam stabilizer is gradually injected into the cement paste, and stirring is continued during the injection process to ensure uniform distribution. This prevents local concentration or uneven distribution of the foam stabilizer in the concrete, thereby ensuring the performance and quality of the concrete.

4. The open-closed-hole controlled electromagnetic protective concrete according to claim 1, characterized in that, The water-reducing agent is at least one of naphthalene-based high-efficiency water-reducing agent, aliphatic high-efficiency water-reducing agent, amino high-efficiency water-reducing agent, and polycarboxylate high-performance water-reducing agent, and the amount added is 1-2% of the mass of water; The quick-setting agent is an alkali-free quick-setting agent with aluminum sulfate as the main component. The mass of the quick-setting agent is 3-4% of the mass of water, which enables the mixed slurry to solidify and harden immediately after foaming, while maintaining good fluidity of the mixed slurry before and during foaming. The foaming agent is hydrogen peroxide or plant protein.

5. The open-closed-hole controlled electromagnetic protective concrete according to claim 3, characterized in that, By adding different amounts of foaming agent, foams with densities ranging from 400 to 1200 kg / m³ can be produced. 3 With the addition of foaming agent, the density of foamed concrete gradually decreases, while the porosity gradually increases within the range of 37% to 72%. As the density increases, the effective absorption loss peak first increases and then decreases, thus achieving electromagnetic absorption loss control at different peak values ​​in specific wavebands.

6. The open-closed-hole controlled electromagnetic protective concrete according to claim 3, characterized in that, The specific rules for freely adjusting the reflection loss of electromagnetic waves in a specific band are as follows: When the effective absorption band of the target is 1.0~5.0GHz, the corresponding porosity of the open-closed pore controlled electromagnetic shielding concrete is 4%; When the effective absorption band of the target is 5.0~11.0GHz, the corresponding porosity of the open-closed pore controlled electromagnetic shielding concrete is 30%. When the effective absorption band of the target is 11.0~14.0GHz, the porosity of the open-closed pore controlled electromagnetic shielding concrete is 77%. When the effective absorption band of the target is 14.0~18.0GHz, the porosity of the open-closed pore controlled electromagnetic shielding concrete is 98%. The effective absorption band and its corresponding aperture ratio are represented in the form of data points. For any given effective absorption band, if it is not within the above range or overlaps with the above range, the aperture ratio of any given absorption band is calculated by linear interpolation. The specific process is as follows: Using any given effective absorption band as the target band, for the target band, find the two known data points that are closest to the initial value of the target band, and use a linear interpolation formula to calculate the aperture ratio corresponding to the target band. The specific calculation method is as follows: Let the known data points approaching the target band be (f1, r1) and (f2, r2), where f1 and f2 represent the initial values ​​of the band, and r1 and r2 represent the corresponding aperture ratios; for the initial value f of the target band... t The corresponding aperture ratio r is calculated using a linear interpolation formula. t for: r t = r1+ (f t - f1) / (r2 - r1) × (f2 - f1)。 7. The open-closed-hole controlled electromagnetic protective concrete according to claim 6, characterized in that, The porosity of open-closed-pore controlled electromagnetic shielding concrete is controlled by adjusting the ratio of hexadecyltrimethylammonium bromide (CTAB), TX-100, sodium dodecyl sulfate (SDS), and Tween T60. The specific process is as follows: By setting the mass ratio of sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB) to 5:0, open-closed pore controlled electromagnetic protective concrete with an open porosity of 1% to 25% was obtained. By setting the mass ratio of sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB) to 15:1, open-closed pore controlled electromagnetic protective concrete with an open porosity of 26% to 50% was obtained. By setting the mass ratio of sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB) to 10:3, open-closed pore controlled electromagnetic protective concrete with an open porosity of 51% to 79% was obtained. By setting the mass ratio of sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB) to 0:4, open-closed pore controlled electromagnetic protective concrete with an open porosity of 80% to 99% was obtained.

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