A high-ductility cement-based composition with wave-absorbing performance and a preparation method thereof

Abstract

The application relates to the field of building materials, and particularly discloses a high-ductility cement-based composition with wave-absorbing performance and a preparation method thereof, which comprises the following raw materials: cement, sand, water, copper residue, a ferrite-copper residue compound, fly ash, mineral powder, an additive, modified carbon fibers loaded with a mica powder-modified waste rubber powder composite filler and PE fibers; the ferrite-copper residue compound is prepared by mixing iron-containing electroplating sludge and an iron salt, adding water to form a slurry, adding copper residue and calcium oxide into the slurry, and then carrying out high-temperature oxidation treatment in an air atmosphere, and crushing; the preparation method comprises the following steps: mixing the cement, sand, copper residue, ferrite-copper residue compound, fly ash and mineral powder, adding the modified carbon fibers loaded with the mica powder-modified waste rubber powder composite filler and the PE fibers, stirring, and preparing a primary mixture; mixing the additive and water, adding the primary mixture, and stirring to prepare the cement-based composition. The application has the characteristics of preparing the cement-based material with high ductility and wave-absorbing performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building materials, more particularly, it relates to a high-ductility cement-based composition with wave-absorbing performance and a preparation method thereof. BACKGROUND

[0002] With the rapid development of modern electronic technology and wireless communication technology, electromagnetic wave radiation has become a ubiquitous source of environmental pollution. Electromagnetic pollution not only poses a potential threat to human health, such as interfering with the nervous system and affecting cardiovascular function, but also causes interference to the normal operation of electronic devices, affecting their performance and lifespan. In particular, in military facilities, computer processing systems will radiate a large amount of electromagnetic waves in automated combat command systems, and the circuits of electronic devices are sensitive to electromagnetic radiation and will interfere with each other, resulting in the system not working properly. Therefore, developing materials with high-efficiency electromagnetic wave absorption performance to reduce the harm of electromagnetic radiation to the environment and human body has become an important direction of current material science research.

[0003] In particular, in the fields of military protection, civil construction, and special environments, it is necessary to have both electromagnetic protection and structural reinforcement functions, such as military facilities that need to cope with high-tech reconnaissance and precision strikes, requiring building materials to have both stealth and blast resistance performance. In civil construction, large-scale substations, radar stations, and high-density electronic equipment areas urgently need electromagnetic shielding to ensure the normal operation of equipment and human health. However, cement-based materials, as the main structural material in the construction field, have the advantages of low cost and convenient construction, but their electromagnetic wave absorption performance is poor, which cannot meet the needs of modern buildings for electromagnetic protection. In addition, traditional cement-based materials often exhibit brittle fracture characteristics when subjected to external forces, lacking sufficient ductility and toughness, which limits their application in complex environments such as earthquake resistance and impact resistance.

[0004] In view of the above problems, it is urgent to develop a cement-based material with high ductility and wave-absorbing performance to meet the needs. SUMMARY

[0005] In order to obtain a cement-based material with high ductility and wave-absorbing performance, the present application provides a high-ductility cement-based composition with wave-absorbing performance and a preparation method thereof.

[0006] In the first aspect, the present application provides a high-ductility cement-based composition with wave-absorbing performance, which adopts the following technical scheme:

[0007] A high-ductility cement-based composition with wave-absorbing performance comprises the following raw materials by weight:

[0008] 250-350 parts of cement, 450-520 parts of sand, 150-240 parts of water, 280-320 parts of copper slag, 170-230 parts of ferrite-copper slag composite, 30-50 parts of fly ash, 15-40 parts of mineral powder, 1-3 parts of additive agent, and 10-20 parts of modified carbon fiber loaded with mica powder-modified waste rubber powder composite filler, and 15-30 parts of PE fiber;

[0009] The ferrite-copper slag composite is prepared by mixing the iron-containing electroplating sludge with an iron salt, adding water to form a slurry, adding copper slag and calcium oxide to the slurry, and then performing high-temperature oxidation treatment in an air atmosphere, and crushing to obtain the ferrite-copper slag composite.

[0010] By using the above technical scheme, in the cement-based composition of the present application, copper slag and ferrite-copper slag composite are used to replace part of the sand. On the one hand, the copper slag has a certain hardness and strength, and can be used as aggregate in the cement-based composition to form an effective skeleton structure, thereby improving the mechanical properties such as compressive strength of the composition. The use of copper slag instead of sand reduces the exploitation of natural sand resources, alleviates the shortage of sand resources, and protects the ecological environment. More importantly, copper slag is an industrial waste slag produced in the copper smelting process. As molten slag produced in the copper smelting process, it is formed into a rhombus-shaped, glassy granular metallurgical slag by water quenching and rapid cooling. It contains iron compounds, especially ferric oxide, which is a magnetic and dielectric material with both magnetic and electric absorption functions. Therefore, by using it instead of sand as aggregate in the cement-based composition, the waste is recycled, the copper slag is reduced, the pressure on the environment is reduced, and the iron oxide compound as a wave-absorbing material makes the cement-based composition have wave-absorbing properties.

[0011] On this basis, the iron-containing electroplating sludge contains metal elements such as iron and copper, and these iron oxides have magnetic loss and dielectric loss characteristics and can absorb electromagnetic waves, thereby providing a basis for serving as a wave-absorbing material. Then, the iron-containing electroplating sludge is mixed with iron sludge and then added to water, iron salt is added to supplement the iron source, and then the mixture is mixed with copper slag and calcium oxide and then subjected to high-temperature oxidation treatment, so that the iron-containing substances are better oxidized to form ferrite-containing ferrite, and the nickel and other elements in the iron-containing electroplating sludge dope the iron oxide in the process to adjust the electromagnetic parameters and achieve wider-band electromagnetic wave absorption. The addition of calcium oxide helps to achieve ferrite reaction and can reduce the iron olivine structure in the copper slag and promote the release of ferrous iron to facilitate the formation of ferrite. After high-temperature oxidation treatment, the low-valence iron in the copper slag and the iron-containing electroplating sludge is oxidized to high-valence iron, thereby enhancing the magnetic loss and dielectric loss, and promoting the crystallization of iron oxides, making the grain size and morphology more uniform and conducive to improving the wave-absorbing performance. In addition, some impurities in the copper slag and the iron-containing electroplating sludge can be removed, reducing the negative impact on the wave-absorbing performance. Ultimately, it is found that the ferrite-copper slag composite significantly improves the wave-absorbing performance compared to single copper slag, and the cement-based composition prepared has good wave-absorbing performance.

[0012] The addition of modified carbon fibers and PE fibers improves the ductility of the composition, and the uniform dispersion of the ferrite-copper slag composite in the cement matrix forms an effective reinforcing phase, improving the ductility of the composition. The addition of fly ash and mineral powder improves the workability of the cement matrix and enhances the durability. Ultimately, the cement-based composition prepared in the present application has good toughness and good wave-absorbing performance.

[0013] Optionally, the ferrite-copper slag composite is prepared by the following method:

[0014] The iron-containing electroplating sludge is dried and broken into sludge particles of 1-3 mm, then mixed with ferrous sulfate and added to water, stirred to form a slurry, then copper slag with a particle size of 1.5-2.36 mm and calcium oxide are added to the slurry, stirred to prepare a mixture, then the mixture is heated to 800-1000℃ and treated in an air atmosphere for 2-4h, then cooled to room temperature and broken to prepare a ferrite-copper slag composite with a particle size of 0.5-3mm.

[0015] By using the above technical solution, the particle size of the iron-containing electroplating sludge and copper slag raw materials is controlled, which helps to increase the specific surface area and improve the reactivity. Ultimately, the particle size of the composite is controlled after oxidation treatment and breaking, which on the one hand regulates the fluidity of the cement-based composition to meet the use requirements, and on the other hand, the particle size affects the mixing and dispersibility of the cement matrix and the wave-absorbing performance. The cement composition prepared by using the above particle size has better comprehensive performance.

[0016] Optionally, in the preparation of the ferrite-copper slag composite, the amount of ferrous sulfate added is 5-12wt% of the sludge particles, the mass ratio of sludge particles to water is 1:(3-4), and the mass ratio of sludge particles to copper slag is 1:(2-3), and the amount of calcium oxide added is 1-3wt% of the amount of copper slag.

[0017] By adopting the above technical solution, the control of the above raw material ratio is helpful for the mass transfer and ion diffusion between the reactants, promotes the generation and distribution of the wave-absorbing product such as ferrite, and improves the wave-absorbing performance.

[0018] Optionally, the particle size of the copper slag in the raw material of the high-ductility cement-based composition is 0.15-1.5mm.

[0019] By adopting the above technical solution, the particle size of the copper slag and the ferrite-copper slag composite in this application forms a gradient particle size combination. On the one hand, the larger particle size of the composite particles provides rolling and filling effect, and the smaller particle size of the copper slag particles further fills the pores and provides lubrication, and the two synergistically make the cement achieve better fluidity. On the other hand, the larger particle size of the ferrite-copper slag composite particles can produce strong scattering effect on electromagnetic waves. When electromagnetic waves enter the cement composition, the large particles will change the propagation direction of electromagnetic waves, increase the propagation path of electromagnetic waves in the composition, thereby increasing the opportunity for electromagnetic waves to be absorbed. The small particle size copper slag is filled in the gap between the large particle size ferrite-copper slag composite particles, forming a more refined wave-absorbing structure. The two form more interfaces, enhancing the reflection and scattering of electromagnetic waves at the interface, thereby improving the wave-absorbing performance. Moreover, the two form a multi-level particle size distribution system. The large particle size composite particles act as scattering centers for electromagnetic waves, dispersing electromagnetic waves to the surrounding small particle size copper slag particles for preliminary scattering and absorption. The small particle size particles further absorb the primary scattered electromagnetic waves. This way, electromagnetic waves can be reflected and absorbed multiple times in the material, improving the wave-absorbing frequency bandwidth and reflection loss, and improving the wave-absorbing efficiency.

[0020] Optionally, the copper slag and the ferrite-copper slag composite are added after being treated with a silane coupling agent solution. Specifically, the copper slag and the ferrite-copper slag composite are respectively placed in a 3-aminopropyl triethoxysilane ethanol solution with a mass concentration of 25-35%, and stirred at 40-50°C for 40-60min, and then filtered and dried.

[0021] By adopting the above technical solution, the copper slag and the ferrite-copper slag composite are respectively treated by immersing in a silane coupling agent solution. An organic-inorganic interface layer is formed on the surface of the particles. In the case of little influence on the wave-absorbing performance, the amino group in the silane coupling agent can complex with calcium ions in the cement hydration product, improving the compatibility of the copper slag and the ferrite-copper slag composite with the cement, improving the interface bonding between the particles and the cement, and helping to form a more uniform wave-absorbing structure.

[0022] Optionally, the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler is prepared by the following method:

[0023] The carbon fiber is treated in a nitric acid solution with a mass concentration of 55-65wt% for 20-40min, and the treatment temperature is 70-80℃, and then the pretreated carbon fiber is obtained after cooling;

[0024] The polyvinyl alcohol is mixed with water in a mass ratio of 1: (3-4), and then the mica powder-modified waste rubber powder composite filler is added, and then the mixture is coated on the pretreated carbon fiber, and then the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler is obtained after drying;

[0025] The polyvinyl alcohol is added in an amount of 3-5wt% of the pretreated carbon fiber, and the mass ratio of the mica powder-modified waste rubber powder composite filler to the pretreated carbon fiber is 1: (2-3).

[0026] By adopting the above technical scheme, the addition of the PE fiber in the present application can significantly improve the ductility of the cement composition, and the addition of the carbon fiber can further improve the ductility of the cement-based composite material, play a bridging role, and can inhibit the expansion of cracks. Moreover, the carbon fiber in the present application has good electrical conductivity, can serve as a transmission channel for electromagnetic waves, and can make the electromagnetic waves more easily enter the material interior to be absorbed by the copper slag and the ferrite-copper slag composite, so as to promote the conduction loss of the electromagnetic waves in the matrix. Finally, the modified carbon fiber and the PE fiber in the present application are matched to improve the comprehensive performance of the wave-absorbing performance and the ductility of the cement composition.

[0027] Optionally, the mica powder-modified waste rubber powder composite filler is prepared by the following method:

[0028] 1) Dissolve the waste rubber powder in toluene, add maleic anhydride and benzoyl peroxide, heat to 65-80℃, react for 2-3h, then cool, filter, and obtain a preliminary mixture;

[0029] 2) Dissolve the amino silane coupling agent and PAMAM in an ethanol solution, then add the preliminary mixture, react at 65-75℃ for 40-60min, then add hydroxyl silicone oil, continue to react for 60-90min, then cool and filter, and dry to obtain the modified waste rubber powder;

[0030] 3) Mix the mica powder with the modified waste rubber powder, then mix and disperse in a sodium dodecyl sulfate solution to obtain a suspension, then dry the suspension, hot-press at 150-170℃ and 8-12MPa, then crush to obtain the mica powder-modified waste rubber powder composite filler.

[0031] By adopting the technical scheme, the addition of the carbon fiber can improve the wave-absorbing performance of the cement composition, but the high modulus of the carbon fiber can easily cause brittle failure, so in the present application, the mica powder-modified waste rubber powder composite filler is loaded on the surface of the carbon fiber, the waste rubber powder is first polymerized with maleic anhydride under the action of an initiator, the unsaturated double bond in the waste rubber powder is polymerized with the maleic anhydride, and a carboxyl functional group is introduced, then the waste rubber powder is modified by an amino silane coupling agent and PAMAM, the amino silane coupling agent is bonded to the surface hydroxyl group of the waste rubber powder through a silicon-oxygen group, and the amino group of the amino silane coupling agent is chemically bonded to the introduced carboxyl group, and the PAMAM is also bonded to the surface of the waste rubber powder through the amino group and the introduced carboxyl group, so that more amino groups are introduced, so that the compatibility of the waste rubber powder with the cement aggregate can be improved, then the hydroxyl silicone oil is used, the hydroxyl group of the hydroxyl silicone oil is chemically bonded to the amino group and the carboxyl group, and the introduction of the hydroxyl silicone oil further improves the ductility of the composite filler, and the hydroxyl silicone oil can also reduce the surface tension of the cement slurry and increase the flowability of the cement slurry, so that the influence of the particles such as copper slag on the flowability can be further improved, and finally the cement composition has more excellent comprehensive performance.

[0032] Finally, the mica powder and the modified waste rubber powder are mixed and dispersed in a sodium dodecyl sulfate solution to form a suspension, which is helpful to the uniform dispersion of the two, and then hot pressing is performed to make the waste rubber powder partially melt and fill between the layers of the mica powder to form a composite. In addition, the layered structure of the mica powder causes the electromagnetic wave to be reflected and scattered multiple times between the layers when propagating inside, increasing the propagation path of the electromagnetic wave in the material and improving the probability of being absorbed. Finally, when the mica powder-modified waste rubber powder composite particles are loaded on the carbon fiber, the brittleness of the carbon fiber is reduced, the ductility of the cement composition is improved, and the wave-absorbing performance is further improved.

[0033] Optionally, in the preparation process of the mica powder-modified waste rubber powder composite filler, in step 1), the addition amount of the waste rubber powder to maleic anhydride is 1: (0.3-0.4), and the addition amount of benzoyl peroxide is 0.5-3 wt% of the addition amount of the waste rubber powder.

[0034] In step 2), the mass ratio of the amino silane coupling agent to PAMAM is 1: (0.2-0.4), and the mass ratio of the amino silane coupling agent to the initial mixture is 1: (3-4), and the addition amount of the hydroxyl silicone oil is 1-3 wt% of the initial mixture.

[0035] In step 3), the mass ratio of the mica powder to the modified waste rubber powder is 1: (0.8-0.9).

[0036] Optionally, the additive includes a polycarboxylic acid water reducing agent and sodium dodecyl benzene sulfonate in a mass ratio of 1: (1.8-2.2).

[0037] By adopting the technical scheme, sodium dodecyl benzene sulfonate is used as an anionic surfactant, and negative ions are dissociated in water, which can be adsorbed on the surface of copper slag and ferrite-copper slag composite particles to make the surface of the particles carry negative charges. Since the surface of the cement particles also usually carries negative charges, the electrostatic repulsion between the particles is increased, thereby preventing the particles from agglomerating and improving the dispersibility. At the same time, the surfactant molecules can form a lubricating film between the particles and the cement body to improve the compatibility. By improving the dispersibility of the particles, the electromagnetic waves can be more uniformly propagated and absorbed in the cement composition, which helps to improve the wave absorption performance.

[0038] In a second aspect, the application provides a preparation method of a high-ductility cement-based composition with wave absorption performance, which adopts the following technical scheme:

[0039] The preparation method of the high-ductility cement-based composition with wave absorption performance comprises the following steps: mixing cement, sand, copper slag, ferrite-copper slag composite, fly ash and mineral powder, then adding modified carbon fibers and PE fibers loaded with mica powder-modified waste rubber powder composite fillers to stir to obtain a preliminary mixture;

[0040] After mixing the admixture with water, the preliminary mixture is added and stirred to obtain the high-ductility cement-based composition with wave absorption performance.

[0041] In summary, the application has the following beneficial effects:

[0042] 1. The cement-based composition in the application contains iron compounds in the copper slag, especially ferric oxide, which is both a magnetic medium material and a dielectric material, and has both magnetic absorption and electric absorption functions. Therefore, the copper slag is used as aggregate in the cement-based composition instead of sand, which realizes the resource utilization of waste, reduces the discharge of copper slag and reduces the pressure on the environment. Moreover, the iron oxide compound in the copper slag serves as a wave absorption material, so that the prepared cement-based composition has wave absorption performance.

[0043] 2、The iron-containing electroplating sludge in the application contains metal elements such as iron and copper, and these iron oxides have magnetic loss and dielectric loss characteristics, can absorb electromagnetic waves, and provide a basis for being used as a wave-absorbing material. Then, the iron-containing electroplating sludge is mixed with iron sludge and added to water, iron salt supplements iron source, and then mixed with copper slag and calcium oxide and subjected to high-temperature oxidation treatment, so that the iron-containing substances in it are better oxidized to form ferrite-containing ferrite, and the nickel and other elements in the iron-containing electroplating sludge dope the iron oxide in the process to adjust its electromagnetic parameters, realize wider-band electromagnetic wave absorption, and the addition of calcium oxide helps to realize the ferrite reaction, which can reduce the iron olivine structure in the copper slag and promote the release of ferrous iron to facilitate the formation of ferrite. After high-temperature oxidation treatment, the low-valence iron in the copper slag and the iron-containing electroplating sludge is oxidized to high-valence iron, thereby enhancing the magnetic loss and dielectric loss, and promoting the crystallization of iron oxides, making the grain size and morphology more uniform, which is conducive to improving the wave-absorbing performance. It can also remove part of the impurities in the copper slag and the iron-containing electroplating sludge, reduce the negative impact on the wave-absorbing performance, and finally find that the ferrite-copper slag composite significantly improves the wave-absorbing performance compared with single copper slag, and the prepared cement-based composition has good wave-absorbing performance. DETAILED DESCRIPTION

[0044] The application will be further described in detail below in conjunction with the examples, and it is particularly pointed out that: in the following examples, the specific conditions are not specified, and the conventional conditions or the conditions recommended by the manufacturer are used. The raw materials used in the following examples can be obtained from ordinary commercial sources unless otherwise specified.

[0045] In the following examples, P.O 42.5 ordinary portland cement is selected as the cement; Class II fly ash is selected as the fly ash, S95 grade mineral powder is selected as the mineral powder, sand with a fineness modulus of 2.5-3.2 is selected as the sand, and polycarboxylic acid water reducing agent is selected as the polycarboxylic acid water reducing agent from Shandong Jinrong Chemical Technology Co., Ltd.

[0046] The mass percentage of iron elements in the copper slag is 22.54%, the mass percentage of copper elements is 1.45%, and the rest is zinc, aluminum, silicon and other elements.

[0047] The iron-containing electroplating sludge is the product produced after adding iron salts to adjust the pH value and adding flocculants to precipitate in the electroplating process and electroplating wastewater. In the following examples, the mass percentage of iron elements in the iron-containing electroplating sludge is 15.68%, the mass percentage of nickel elements is 13.47%, and the rest is copper and other elements.

[0048] The hydroxyl silicone oil used in the following preparation examples has a hydroxyl content of 10%, a viscosity (25°C, mm 2 / S) of 30 mm 2 / S.

[0049] The following preparation example is a preparation example of a ferrite-copper residue composite.

[0050] Preparation Example 1

[0051] A method for preparing a ferrite-copper residue composite, comprising the following steps:

[0052] The iron-containing electroplating sludge is dried to a water content of less than 1%, and then crushed into sludge particles of 1-3 mm. Then, ferrous sulfate is mixed with the sludge particles, and water is added. After stirring at a speed of 250 r / min for 15 min, a slurry is formed. The amount of ferrous sulfate added is 8 wt% of the sludge particles, and the mass ratio of the sludge particles to water is 1:3.5.

[0053] Then, copper residue with a particle size of 1.5-2.36 mm and calcium oxide are added to the slurry. After stirring at a speed of 400 r / min for 20-30 min, a mixture is prepared. The mass ratio of the sludge particles to copper residue is 1:2.5, and the amount of calcium oxide added is 2 wt% of the amount of copper residue added.

[0054] Then, the mixture is first heated at a rate of 8℃ / min to 900℃, treated in an air atmosphere for 3 h, and then cooled to room temperature. After crushing, a ferrite-copper residue composite with a particle size of 0.5-3 mm is prepared.

[0055] Preparation Example 2

[0056] A method for preparing a ferrite-copper residue composite, comprising the following steps:

[0057] The iron-containing electroplating sludge is dried to a water content of less than 1%, and then crushed into sludge particles of 1-3 mm. Then, ferrous sulfate is mixed with the sludge particles, and water is added. After stirring at a speed of 200 r / min for 20 min, a slurry is formed. The amount of ferrous sulfate added is 5 wt% of the sludge particles, and the mass ratio of the sludge particles to water is 1:3.

[0058] Then, copper residue with a particle size of 1.5-2.36 mm and calcium oxide are added to the slurry. After stirring at a speed of 300 r / min for 30 min, a mixture is prepared. The mass ratio of the sludge particles to copper residue is 1:2, and the amount of calcium oxide added is 1 wt% of the amount of copper residue added.

[0059] Then, the mixture is first heated at a rate of 5℃ / min to 800℃, treated in an air atmosphere for 4 h, and then cooled to room temperature. After crushing, a ferrite-copper residue composite with a particle size of 0.5-3 mm is prepared.

[0060] Preparation Example 3

[0061] A method for preparing a ferrite-copper residue composite, comprising the following steps:

[0062] The iron-containing electroplating sludge is dried to a water content of less than 1%, and then crushed into sludge particles of 1-3 mm, and then mixed with ferrous sulfate and water, and stirred at a speed of 300 r / min for 10 min to form a slurry, the ferrous sulfate is added in an amount of 12 wt% of the sludge particles, and the mass ratio of the sludge particles to water is 1:4;

[0063] Then copper slag with a particle size of 1.5-2.36 mm and calcium oxide are added to the slurry, and stirred at a speed of 500 r / min for 20 min to prepare a mixture, the mass ratio of the sludge particles to the copper slag is 1:3, and the calcium oxide is added in an amount of 3 wt% of the copper slag;

[0064] Then the mixture is first heated to 1000℃ at a heating rate of 10℃ / min, treated in an air atmosphere for 2h, and then cooled to room temperature and crushed to prepare a 0.5-3mm ferrite-copper slag composite.

[0065] Comparative Preparation Example 1

[0066] A method for preparing a ferrite-copper slag composite, which is prepared according to the method in Preparation Example 1, except that no calcium oxide is added to the slurry.

[0067] The following preparation example is a preparation example of modified carbon fibers loaded with mica powder-modified waste rubber powder composite filler.

[0068] Preparation Example 4

[0069] A method for preparing modified carbon fibers loaded with mica powder-modified waste rubber powder composite filler, comprising the following steps:

[0070] S1, treating carbon fibers in a 60 wt% nitric acid solution for 30 min at a treatment temperature of 75℃, cooling, to prepare pretreated carbon fibers, and the mass ratio of the carbon fibers to the nitric acid solution is 1:9;

[0071] S2, preparing a mica powder-modified waste rubber powder composite filler, specifically comprising the following steps:

[0072] 1), dissolving waste rubber powder in 3 times the amount of toluene, adding maleic anhydride and benzoyl peroxide, heating to 70℃, and reacting for 2.5h, then cooling and filtering to prepare a preliminary mixture, the mass ratio of the waste rubber powder to the maleic anhydride is 1:0.3, and the amount of the benzoyl peroxide added is 1.5 wt% of the amount of the waste rubber powder added;

[0073] 2), mixing amino silane coupling agent KH-550 and PAMAM according to 1:0.3 mass ratio, dissolving in ethanol solution (ethanol and water are mixed according to 1:1.2 mass ratio), then adding the initial mixture obtained in step 1), and then reacting at 70 DEG C for 50 min, then adding hydroxyl silicone oil, continuing to react for 75 min, then cooling, filtering and drying to obtain modified waste rubber powder, the mass ratio of amino silane coupling agent to initial mixture is 1:3.5, and the addition amount of hydroxyl silicone oil is 2wt% of the initial mixture;

[0074] 3), mixing mica powder and modified waste rubber powder according to 1:0.8 mass ratio, mixing and dispersing in sodium dodecyl sulfate solution (sodium dodecyl sulfate and water are mixed according to 1:12 mass ratio), to obtain a suspension, then drying the suspension, hot pressing at 160 DEG C and 10 MPa, and then crushing to obtain mica powder-modified waste rubber powder composite filler;

[0075] S3, mixing polyvinyl alcohol and water according to 1:3.5 mass ratio, adding mica powder-modified waste rubber powder composite filler, mixing, and coating on pretreated carbon fiber, drying and curing at 80 DEG C to obtain modified carbon fiber loaded with mica powder-modified waste rubber powder composite filler;

[0076] Among them, the addition amount of polyvinyl alcohol is 4wt% of the pretreated carbon fiber, and the mass ratio of mica powder-modified waste rubber powder composite filler to pretreated fiber is 1:2.5.

[0077] Preparation Example 5

[0078] A method for preparing a modified carbon fiber loaded with a mica powder-modified waste rubber powder composite filler, comprising the following steps:

[0079] S1, treating carbon fiber in a 55wt% nitric acid solution for 40 min, the treatment temperature is 70 DEG C, cooling to obtain pretreated carbon fiber, the mass ratio of carbon fiber to nitric acid solution is 1:8;

[0080] S2, preparing a mica powder-modified waste rubber powder composite filler, specifically comprising the following steps:

[0081] 1), dissolving waste rubber powder in 2 mass times of toluene, adding maleic anhydride and benzoyl peroxide, heating to 65 DEG C, reacting for 3h, cooling, filtering to obtain an initial mixture, the addition amount of waste rubber powder to maleic anhydride is 1:0.3, and the addition amount of benzoyl peroxide is 0.5wt% of the addition amount of waste rubber powder;

[0082] 2), mixing amino silane coupling agent KH-550 and PAMAM according to 1:0.2 mass ratio, dissolving in ethanol solution (ethanol and water are mixed according to 1:1.2 mass ratio), then adding the initial mixture obtained in step 1), and then reacting at 65 DEG C for 60 min, then adding hydroxyl silicone oil, continuing to react for 60 min, then cooling, filtering and drying to obtain modified waste rubber powder, the mass ratio of amino silane coupling agent to initial mixture is 1:3, and the addition amount of hydroxyl silicone oil is 1wt% of the initial mixture;

[0083] 3), mixing mica powder and modified waste rubber powder according to 1:0.8 mass ratio, mixing and dispersing in sodium dodecyl sulfate solution (sodium dodecyl sulfate and water are mixed according to 1:12 mass ratio), to obtain a suspension, then drying the suspension, hot pressing at 150 DEG C and 8 MPa, and then crushing to obtain mica powder-modified waste rubber powder composite filler;

[0084] S3, mixing polyvinyl alcohol and water according to 1:3 mass ratio, adding mica powder-modified waste rubber powder composite filler, mixing, and coating on pretreated carbon fiber, drying and curing at 80 DEG C to obtain modified carbon fiber loaded with mica powder-modified waste rubber powder composite filler;

[0085] Among them, the addition amount of polyvinyl alcohol is 3wt% of the pretreated carbon fiber, and the mass ratio of mica powder-modified waste rubber powder composite filler to pretreated fiber is 1:2.

[0086] Preparation Example 6

[0087] A method for preparing a modified carbon fiber loaded with a mica powder-modified waste rubber powder composite filler, comprising the following steps:

[0088] S1, treating carbon fiber in a 65wt% nitric acid solution for 20 min, the treatment temperature is 80 DEG C, cooling to obtain pretreated carbon fiber, the mass ratio of carbon fiber to nitric acid solution is 1:8;

[0089] S2, preparing a mica powder-modified waste rubber powder composite filler, specifically comprising the following steps:

[0090] 1), dissolving waste rubber powder in 4 mass times of toluene, adding maleic anhydride and benzoyl peroxide, heating to 80 DEG C, reacting for 2h, cooling, filtering to obtain an initial mixture, the addition amount of waste rubber powder to maleic anhydride is 1:0.4, and the addition amount of benzoyl peroxide is 3wt% of the addition amount of waste rubber powder;

[0091] 2), mixing amino silane coupling agent KH-550 and PAMAM according to a mass ratio of 1:0.4, dissolving in an ethanol solution (ethanol and water are mixed according to a mass ratio of 1:1.2), then adding the premix obtained in step 1), and reacting at 75 DEG C for 40 min, then adding hydroxyl silicone oil, continuing to react for 90 min, cooling, filtering, and drying to obtain modified waste rubber powder, the mass ratio of amino silane coupling agent to premix is 1:4, and the addition amount of hydroxyl silicone oil is 3 wt% of the premix;

[0092] 3), mixing mica powder and modified waste rubber powder according to a mass ratio of 1:0.9, mixing and dispersing in a sodium dodecyl sulfate solution (sodium dodecyl sulfate and water are mixed according to a mass ratio of 1:12), to obtain a suspension, then drying the suspension, hot-pressing at 170 DEG C and 12 MPa, and crushing to obtain a mica powder-modified waste rubber powder composite filler;

[0093] S3, mixing polyvinyl alcohol and water according to a mass ratio of 1:4, adding the mica powder-modified waste rubber powder composite filler, mixing, and coating on pretreated carbon fibers, drying and curing at 80 DEG C to obtain modified carbon fibers loaded with the mica powder-modified waste rubber powder composite filler;

[0094] The addition amount of polyvinyl alcohol is 5 wt% of the pretreated carbon fibers, and the mass ratio of the mica powder-modified waste rubber powder composite filler to the pretreated fibers is 1:3.

[0095] Comparative Preparation Example 2

[0096] A method for preparing modified carbon fibers, which is performed according to the method in Preparation Example 4, except that the step S2 operation is not performed, and the mica powder-modified waste rubber powder composite filler in the step S3 operation is replaced by an equal amount of mica powder.

[0097] Comparative Preparation Example 3

[0098] A method for preparing modified carbon fibers, which is performed according to the method in Preparation Example 4, except that the step S2 operation is not performed, and the mica powder-modified waste rubber powder composite filler in the step S3 operation is replaced by an equal amount of waste rubber powder.

[0099] Example 1

[0100] A method for preparing a high-ductility cement-based composition with wave-absorbing performance, comprising the following steps:

[0101] After 300 parts of cement, 480 parts of sand, 300 parts of copper slag with particle size of 0.15-1.5 mm, 200 parts of the ferrite-copper slag composite with particle size of 0.5-3 mm prepared in Preparation Example 1, 40 parts of fly ash and 25 parts of mineral powder are mixed, 15 parts of the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler prepared in Preparation Example 4 and 22 parts of PE fiber are added and stirred to prepare a preliminary mixture;

[0102] After 2 parts of an admixture including polycarboxylic acid water reducer and sodium dodecyl benzene sulfonate with a mass ratio of 1:2 are mixed with 180 parts of water, the preliminary mixture is added and stirred to prepare a cement-based composition.

[0103] The cement-based composition prepared in Example 1 has a continuous effective bandwidth of 9.4 GHz below -10 dB and a minimum reflectivity of -21.9 dB in a frequency range of 2.0-18.0 GHz.

[0104] Example 2

[0105] A method for preparing a high-ductility cement-based composition having a wave-absorbing property includes the steps of:

[0106] After 250 parts of cement, 450 parts of sand, 280 parts of copper slag with particle size of 0.15-1.5 mm, 170 parts of the ferrite-copper slag composite with particle size of 0.5-3 mm prepared in Preparation Example 2, 30 parts of fly ash and 15 parts of mineral powder are mixed, 10 parts of the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler prepared in Preparation Example 5 and 15 parts of PE fiber are added and stirred to prepare a preliminary mixture;

[0107] After 1 part of an admixture including polycarboxylic acid water reducer and sodium dodecyl benzene sulfonate with a mass ratio of 1:1.8 is mixed with 150 parts of water, the preliminary mixture is added and stirred to prepare a cement-based composition.

[0108] The cement-based composition prepared in Example 2 has a continuous effective bandwidth of 9.0 GHz below -10 dB and a minimum reflectivity of -18.6 dB in a frequency range of 2.0-18.0 GHz.

[0109] Example 3

[0110] A method for preparing a high-ductility cement-based composition having a wave-absorbing property includes the steps of:

[0111] After 350 parts of cement, 520 parts of sand, 320 parts of copper slag with particle size of 0.15-1.5 mm, 230 parts of the ferrite-copper slag composite with particle size of 0.5-3 mm prepared in Preparation Example 3, 50 parts of fly ash and 40 parts of mineral powder are mixed, 20 parts of the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler prepared in Preparation Example 6 and 30 parts of PE fiber are added and stirred to prepare a preliminary mixture;

[0112] After 3 parts of admixture, including polycarboxylate superplasticizer and sodium dodecyl benzene sulfonate with a mass ratio of 1:2.2, were mixed with 240 parts of water, the initial mixture was added and stirred to prepare the cement-based composition.

[0113] The cement-based composition prepared in this example 3 has a continuous effective bandwidth of 9.1 GHz below -10 dB and a minimum reflectivity of -19.7 dB in the frequency range of 2.0-18.0 GHz.

[0114] Example 4

[0115] A method for preparing a high-ductility cement-based composition with wave-absorbing performance was performed according to the method in example 1, except that the copper slag and the ferrite-copper slag composite were added after being treated with a silane coupling agent solution, and the specific operation was as follows: the copper slag and the ferrite-copper slag composite were respectively placed in a 30% mass concentration of 3-aminopropyl triethoxysilane ethanol solution (the ethanol solution was prepared by mixing ethanol and water in a mass ratio of 1:1), stirred at 45°C for 50 min, and then filtered and dried.

[0116] The cement-based composition prepared in this example has a continuous effective bandwidth of 9.9 GHz below -10 dB and a minimum reflectivity of -23.7 dB in the frequency range of 2.0-18.0 GHz.

[0117] Example 5

[0118] A method for preparing a high-ductility cement-based composition with wave-absorbing performance was performed according to the method in example 1, except that the copper slag and the ferrite-copper slag composite were added after being treated with a silane coupling agent solution, and the specific operation was as follows: the copper slag and the ferrite-copper slag composite were respectively placed in a 25% mass concentration of 3-aminopropyl triethoxysilane ethanol solution (the ethanol solution was prepared by mixing ethanol and water in a mass ratio of 1:1), stirred at 40°C for 60 min, and then filtered and dried.

[0119] The cement-based composition prepared in this example has a continuous effective bandwidth of 9.6 GHz below -10 dB and a minimum reflectivity of -22.6 dB in the frequency range of 2.0-18.0 GHz.

[0120] Example 6

[0121] A method for preparing a high-ductility cement-based composition with wave-absorbing performance was performed according to the method in Example 1, except that the copper residue and the ferrite-copper residue composite were added after being treated with a silane coupling agent solution. Specifically, the copper residue and the ferrite-copper residue composite were placed in a 35% mass concentration 3-aminopropyl triethoxysilane ethanol solution (the ethanol solution was prepared by mixing ethanol and water in a mass ratio of 1:1) and stirred at 50°C for 60 min, and then filtered and dried.

[0122] The cement-based composition prepared in this example had a continuous effective bandwidth of 9.8 GHz below -10 dB and a minimum reflectivity of -22.1 dB in the frequency range of 2.0-18.0 GHz.

[0123] Example 7

[0124] A method for preparing a high-ductility cement-based composition with wave-absorbing performance was performed according to the method in Example 1, except that the superplasticizer was a polycarboxylate superplasticizer.

[0125] The cement-based composition prepared in this example had a continuous effective bandwidth of 8.4 GHz below -10 dB and a minimum reflectivity of -16.9 dB in the frequency range of 2.0-18.0 GHz.

[0126] Comparative Example 1

[0127] A method for preparing a high-ductility cement-based composition with wave-absorbing performance was performed according to the method in Example 1, except that the ferrite-copper residue composite was the ferrite-copper residue composite prepared in Comparative Preparation Example 1.

[0128] The cement-based composition prepared in this example had a continuous effective bandwidth of 7.5 GHz below -10 dB and a minimum reflectivity of -14.2 dB in the frequency range of 2.0-18.0 GHz.

[0129] Comparative Example 2

[0130] A method for preparing a high-ductility cement-based composition with wave-absorbing performance was performed according to the method in Example 1, except that the ferrite-copper residue composite was replaced with an equal amount of copper residue having a particle size of 0.15-1.5 mm.

[0131] The cement-based composition prepared in this example had a continuous effective bandwidth of 5.6 GHz below -10 dB and a minimum reflectivity of -11.6 dB in the frequency range of 2.0-18.0 GHz.

[0132] Comparative Example 3

[0133] A method for preparing a high-ductility cement-based composition with wave-absorbing performance is performed according to the method in Example 1, except that the ferrite copper slag composite is replaced by an equal amount of a mixture of sludge particles with a particle size of 1-3 mm and copper slag with a particle size of 1.5-2.36 mm, and the mass ratio of the sludge particles to the copper slag is 1:2.5. The sludge particles are obtained by drying the iron-containing electroplating sludge to a water content of less than 1%, and then crushing the sludge particles to a size of 1-3 mm.

[0134] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 5.2 GHz below -10 dB and a minimum reflectivity of -12.3 dB in the frequency range of 2.0-18.0 GHz.

[0135] Comparative Example 4

[0136] A method for preparing a high-ductility cement-based composition with wave-absorbing performance is performed according to the method in Example 1, except that the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler is replaced by an equal amount of carbon fiber.

[0137] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 6.3 GHz below -10 dB and a minimum reflectivity of -15.8 dB in the frequency range of 2.0-18.0 GHz.

[0138] Comparative Example 5

[0139] A method for preparing a high-ductility cement-based composition with wave-absorbing performance is performed according to the method in Example 1, except that the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler is replaced by an equal amount of the modified carbon fiber prepared in Comparative Preparation Example 2.

[0140] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 8.8 GHz below -10 dB and a minimum reflectivity of -20.9 dB in the frequency range of 2.0-18.0 GHz.

[0141] Comparative Example 6

[0142] A method for preparing a high-ductility cement-based composition with wave-absorbing performance is performed according to the method in Example 1, except that the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler is replaced by an equal amount of the modified carbon fiber prepared in Comparative Preparation Example 3.

[0143] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 6.8 GHz below -10 dB and a minimum reflectivity of -15.6 dB in the frequency range of 2.0-18.0 GHz.

[0144] Performance testing

[0145] The cement-based composite prepared in the examples and comparative examples of the present application was subjected to ultimate tensile value detection according to JC / T 2461-2018 "Mechanical property test method of high ductility fiber reinforced cement-based composite" to characterize its ductility performance, and the detection results are shown in Table 1 below.

[0146] Table 1:

[0147]

[0148] Referring to Table 1 above and the detection of wave absorption performance in the examples and comparative examples, it can be seen that the cement-based composition prepared in the examples has excellent ductility and good wave absorption performance. Combined with the detection results of Example 1 and Examples 4-6, it can be seen that when the copper slag and ferrite-copper slag composite are treated with silane coupling agent and then added, it helps to disperse and compatibility in the cement matrix, not only further improves the wave absorption performance, but also improves the mechanical performance. Combined with the detection results of Example 7, when the admixture only adds polycarboxylic acid water reducer, the wave absorption performance is reduced.

[0149] Referring to the detection results of Example 1 and Comparative Example 1, the addition of calcium oxide during the preparation of the ferrite-copper slag composite has an effect on the crystals of the two, which can significantly improve the wave absorption performance. Combined with the detection results of Comparative Example 2, when only copper slag is added without adding ferrite-copper slag composite in the raw materials, the wave absorption performance is significantly reduced, and the addition of ferrite-copper slag composite significantly improves the wave absorption performance. Combined with the detection results of Comparative Example 3, when only iron-containing electroplating sludge particles and copper slag are added in the raw materials, the wave absorption performance is significantly reduced compared to Example 1, and the wave absorption performance is significantly improved after high-temperature oxidation treatment. Combined with the detection results of Comparative Example 4, when the carbon fiber is not modified and directly added, the wave absorption performance is also reduced, and the addition of mica powder helps to further improve the wave absorption performance. Combined with the detection results of Example 1 and Comparative Example 5, when the composite filler loaded on the carbon fiber in Comparative Example 5 is replaced by mica powder and waste rubber powder is not added, it can be seen that the ductility is significantly reduced. Combined with the detection results of Comparative Example 6, when the carbon fiber only loads waste rubber powder and does not load mica powder, the wave absorption performance is reduced.

[0150] In addition, the 28d compressive strength of the cement-based composition prepared in Examples 1-6 of the present application is 45.8-49.7MPa, and the fluidity is 150-170mm (referring to GB 2419-2005 "Cement mortar fluidity determination method" for fluidity determination).

[0151] In addition, the cement-based composition prepared in Example 1 and Example 4 was subjected to 28d compressive strength, tensile strength and peak strain detection, and the detection results are shown in Table 2.

[0152] Table 2:

[0153]

[0154] In combination with the detection results of Table 2, it can be seen that the cement-based composition prepared in the application has excellent ductility and excellent mechanical properties.

[0155] The specific embodiments are only an explanation of the application, and are not a limitation of the application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the application, they are protected by the Patent Law.

Claims

1. A high-ductility cement-based composition having wave-absorbing properties, characterized in that, The following raw materials are included by weight parts: 250-350 parts of cement, 450-520 parts of sand, 150-240 parts of water, 280-320 parts of copper slag, 170-230 parts of ferrite-copper slag composite, 30-50 parts of fly ash, 15-40 parts of mineral powder, 1-3 parts of additive agent, and 10-20 parts of modified carbon fiber loaded with mica powder-modified waste rubber powder composite filler, and 15-30 parts of PE fiber; The ferrite-copper slag composite is prepared by mixing the iron-containing electroplating sludge with iron salt, then adding water to form a slurry, adding copper slag and calcium oxide to the slurry, and then oxidizing in an air atmosphere, crushing to obtain the ferrite-copper slag composite.

2. The high-ductility cement-based composition with wave-absorbing performance according to claim 1, characterized in that: The ferrite-copper slag composite is prepared by the following method: The iron-containing electroplating sludge is dried and crushed into sludge particles of 1-3 mm, then mixed with ferrous sulfate and water, stirred to form a slurry, then 1.5-2.36 mm copper slag and calcium oxide are added to the slurry, stirred to obtain a mixture, then the mixture is heated to 800-1000℃, treated in an air atmosphere for 2-4 h, then cooled to room temperature and crushed to obtain a ferrite-copper slag composite of 0.5-3 mm.

3. The high-ductility cement-based composition with wave-absorbing performance according to claim 2, characterized in that: During the preparation of the ferrite-copper slag composite, the amount of ferrous sulfate added is 5-12 wt% of the sludge particles, the mass ratio of sludge particles to water is 1:(3-4), and the mass ratio of sludge particles to copper slag is 1:(2-3), and the amount of calcium oxide added is 1-3 wt% of the amount of copper slag added.

4. The high-ductility cement-based composition with wave-absorbing performance according to claim 1, characterized in that: The particle size of the copper slag in the raw materials of the high-ductility cement-based composition is 0.15-1.5 mm.

5. The high-ductility cementitious composition with wave-absorbing performance according to claim 1, characterized in that: The copper slag and the ferrite-copper slag composite are added after being treated with a silane coupling agent solution. The specific operation is as follows: the copper slag and the ferrite-copper slag composite are respectively placed in a 3-aminopropyl triethoxysilane ethanol solution with a mass concentration of 25-35%, stirred at 40-50℃ for 40-60 min, and then filtered and dried.

6. The high-ductility cementitious composition with wave-absorbing performance according to claim 1, characterized in that: The modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler is prepared by the following method: The carbon fiber is treated in a 55-65 wt% nitric acid solution for 20-40 min at a treatment temperature of 70-80℃, and then cooled to obtain pretreated carbon fiber; Polyvinyl alcohol is mixed with water in a mass ratio of 1:(3-4), and then the mica powder-modified waste rubber powder composite filler is added and coated on the pretreated carbon fiber, and then dried to obtain the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler; The amount of polyvinyl alcohol added is 3-5 wt% of the pretreated carbon fiber, and the mass ratio of the mica powder-modified waste rubber powder composite filler to the pretreated fiber is 1:(2-3).

7. The high-ductility cement-based composition with wave-absorbing performance according to claim 1, characterized in that: The mica powder-modified waste rubber powder composite filler is prepared by the following method: 1) Dissolve the waste rubber powder in toluene, add maleic anhydride and benzoyl peroxide, heat to 65-80℃, react for 2-3 h, cool, and then filter to obtain a preliminary mixture; 2) dissolving the amino silane coupling agent and PAMAM in ethanol solution, then adding the initial mixture and reacting at 65-75℃ for 40-60min, then adding hydroxyl silicone oil, continuing to react for 60-90min, then cooling, filtering and drying to obtain the modified waste rubber powder; 3) mixing and dispersing the mica powder and the modified waste rubber powder in a sodium dodecyl sulfate solution to obtain a suspension, then drying the suspension, hot-pressing at 150-170℃ and 8-12MPa, and crushing to obtain the mica powder-modified waste rubber powder composite filler.

8. The high-ductility cement-based composition with wave-absorbing performance according to claim 7, characterized in that: In the preparation of the mica powder-modified waste rubber powder composite filler, in step 1), the addition amount of waste rubber powder to maleic anhydride is 1:(0.3-0.4), and the addition amount of benzoyl peroxide is 0.5-3wt% of the addition amount of waste rubber powder; In step 2), the addition mass ratio of amino silane coupling agent to PAMAM is 1:(0.2-0.4), and the addition mass ratio of amino silane coupling agent to the initial mixture is 1:(3-4), and the addition amount of hydroxyl silicone oil is 1-3wt% of the initial mixture; In step 3), the addition mass ratio of mica powder to modified waste rubber powder is 1:(0.8-0.9).

9. The high-ductility cementitious composition with wave-absorbing performance according to claim 1, characterized in that: The admixture comprises polycarboxylic acid water reducing agent and sodium dodecylbenzenesulfonate in a mass ratio of 1:(1.8-2.2).

10. A method for producing a high-ductility cement-based composition having wave-absorbing properties according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: mixing cement, sand, copper slag, ferrite-copper slag composite, fly ash and mineral powder, adding modified carbon fiber and PE fiber loaded with the mica powder-modified waste rubber powder composite filler and stirring to obtain an initial mixture; mixing the admixture with water, adding the initial mixture and stirring to obtain the product.

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