High-ductility cement-based composition with wave-absorbing property and preparation method of high-ductility cement-based composition

Abstract

The invention 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, the high-ductility cement-based composition comprises the following raw materials: cement, sand, water, copper slag, a ferrite-copper slag compound, fly ash, mineral powder, an additive, modified carbon fiber loaded with mica powder-modified waste rubber powder composite filler, and PE fiber; the ferrite-copper slag compound is prepared by mixing iron-containing electroplating sludge and iron salt, adding water to form slurry, adding copper slag and calcium oxide into the slurry, performing high-temperature oxidation treatment in an air atmosphere, and crushing; the preparation method comprises the following steps: mixing the cement, the sand, the copper slag, the ferrite-copper slag compound, the fly ash and the mineral powder, adding the modified carbon fiber loaded with the mica powder-modified waste rubber powder composite filler and the PE fiber, and stirring to prepare a primary mixture; and mixing the admixture with water, adding the primary mixture, and stirring to obtain the concrete. The preparation method has the characteristic of preparing the cement-based material with high ductility and wave-absorbing property.

Description

Technical Field

[0001] This application relates to the field of building materials, and more specifically, to a highly ductile cement-based composition with wave-absorbing properties and a method for preparing the same. Background Technology

[0002] With the rapid development of modern electronic and wireless communication technologies, electromagnetic radiation has become a widespread 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 interferes with the normal operation of electronic devices, affecting their performance and lifespan. This is especially true in military facilities, where computer processing systems in automated combat command systems radiate large amounts of electromagnetic waves. Since the circuits of electronic devices are highly sensitive to electromagnetic radiation, they can interfere with each other, causing the systems to malfunction. Therefore, developing materials with highly efficient electromagnetic radiation absorption properties to reduce the harm of electromagnetic radiation to the environment and human health has become an important direction in current materials science research.

[0003] Especially in military protection, civilian buildings, and special environments, there is a need for both electromagnetic protection and structural reinforcement. For example, military facilities need to withstand high-tech reconnaissance and precision strikes, requiring building materials to possess both stealth and blast resistance properties. In civilian buildings, large substations, radar stations, and areas with high-density electronic equipment urgently require electromagnetic shielding to ensure the normal operation of equipment and human health. However, cement-based materials, as the main structural materials in the construction field, have advantages such as low cost and convenient construction, but their electromagnetic wave absorption performance is poor, making it difficult to meet the electromagnetic protection requirements of modern buildings. 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] To address the aforementioned issues, there is an urgent need to develop a cement-based material that combines high ductility with wave-absorbing properties to meet the requirements. Summary of the Invention

[0005] In order to obtain a cement-based material that combines high ductility and microwave absorption properties, this application provides a high-ductility cement-based composition with microwave absorption properties and a method for preparing the same.

[0006] In a first aspect, this application provides a highly ductile cement-based composition with microwave absorption properties, employing the following technical solution: A highly ductile cement-based composition with microwave absorption properties comprises the following raw materials in parts by weight: 250-350 parts cement, 450-520 parts sand, 150-240 parts water, 280-320 parts copper slag, 170-230 parts ferrite-copper slag composite, 30-50 parts fly ash, 15-40 parts mineral powder, 1-3 parts admixtures, 10-20 parts modified carbon fiber loaded with mica powder-modified waste rubber powder composite filler, and 15-30 parts PE fiber; The ferrite-copper slag composite is prepared by mixing iron-containing electroplating sludge with iron salts and adding water to form a slurry. Copper slag and calcium oxide are added to the slurry and then subjected to high-temperature oxidation treatment in an air atmosphere. After crushing, the ferrite-copper slag composite is obtained.

[0007] By adopting the above technical solution, the cement-based composition in this application uses copper slag and ferrite-copper slag composite to replace part of the sand. On the one hand, the copper slag has a certain hardness and strength, and when added to the cement-based composition as an aggregate, it can form an effective skeleton structure, improve the mechanical properties of the composition such as compressive strength, and reduce the mining of natural sand resources, alleviate the shortage of sand resources, and protect the ecological environment. More importantly, copper slag is an industrial waste generated during the copper smelting process. As a molten slag generated during the copper smelting process, it is formed into rhomboid and glassy granular metallurgical slag by water quenching and rapid cooling. It contains iron compounds, especially iron(III) oxide, which is both a magnetic and an electrical medium, and has both magnetic and electrical absorption functions. Therefore, using it as an aggregate to replace sand in the cement-based composition realizes the resource utilization of waste, reduces copper slag emissions, and reduces the pressure on the environment. Moreover, the ferrite compound acts as a wave-absorbing material, giving the cement-based composition wave-absorbing properties.

[0008] Based on this, iron-containing electroplating sludge contains metallic elements such as iron and copper. These iron oxides have magnetic and dielectric loss properties, which can absorb electromagnetic waves, providing a basis for its use as a microwave absorbing material. Then, it is mixed with iron sludge and water, with iron salts supplementing the iron source. After mixing with copper slag and calcium oxide, it undergoes high-temperature oxidation treatment, allowing the iron-containing substances to be better oxidized to form ferrite containing iron(III) oxide. Furthermore, elements such as nickel in the iron-containing electroplating sludge dope the iron oxide during the process, adjusting its electromagnetic parameters to achieve wider-band electromagnetic wave absorption. The addition of calcium oxide helps to achieve the ferrite formation reaction and can reduce copper... The ferroolitic structure in the slag promotes the release of ferrous oxide, which is conducive to the formation of ferrite. After high-temperature oxidation treatment, the low-valence iron in copper slag and iron-containing electroplating sludge is oxidized to high-valence iron, thereby enhancing magnetic loss and dielectric loss. It can also promote the crystallization of iron oxide, making its grain size and morphology more uniform, which is beneficial to improving the microwave absorption performance. It can also remove some impurities in copper slag and iron-containing electroplating sludge, reducing the negative impact on microwave absorption performance. Finally, it was found that the use of ferrite-copper slag composite significantly improves its microwave absorption performance compared with copper slag alone. The cement-based composition prepared has good microwave absorption performance.

[0009] The addition of modified carbon fiber and PE fiber improves the ductility of the composition. Combined with the uniform dispersion of ferrite-copper slag composite in the cement matrix, it forms an effective reinforcing phase, which improves the ductility of the composition. The addition of fly ash and mineral powder improves the workability of the cement matrix and enhances its durability. Finally, the cement-based composition prepared in this application has good toughness and good wave absorption properties.

[0010] Optionally, the ferrite-copper slag composite is prepared by the following method: Iron-containing electroplating sludge is dried and crushed into 1-3 mm sludge particles, then mixed with ferrous sulfate and water, and stirred to form a slurry. Copper slag and calcium oxide with a particle size of 1.5-2.36 mm are then added to the slurry and stirred to obtain a mixture. The mixture is then heated to 800-1000℃ and treated in air for 2-4 hours. After cooling to room temperature, it is crushed to obtain a 0.5-3 mm ferrite-copper slag composite.

[0011] By adopting the above technical solution, controlling the particle size of iron-containing electroplating sludge and copper slag raw materials helps to increase their specific surface area and improve their reactivity. Finally, the particle size control of the composite after oxidation treatment and crushing has the following effects: on the one hand, it regulates the flowability of the cement-based composition to meet the application requirements; on the other hand, the particle size affects the mixing and dispersibility of the cement matrix and its wave absorption performance. The cement composition prepared with the above particle size has better comprehensive performance.

[0012] Optionally, when preparing 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), 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.

[0013] By adopting the above technical solution, the control of the above raw material ratio helps the material transport and ion diffusion between reactants, promotes the generation and distribution of microwave absorption products such as ferrite, and improves microwave absorption performance.

[0014] Optionally, the particle size of the copper slag in the raw materials of the high-ductility cementitious composition is 0.15-1.5 mm.

[0015] By adopting the above technical solution, the copper slag and ferrite-copper slag composite particles in this application form a gradient particle size distribution. On the one hand, the larger-sized composite particles provide rolling and filling effects, while the smaller-sized copper slag particles further fill the pores and provide lubrication. The synergy of these two factors enables the cement to achieve better fluidity. On the other hand, the larger-sized ferrite-copper slag composite particles can generate a strong scattering effect on electromagnetic waves. When electromagnetic waves are incident on the cement composition, the large particles will change the propagation direction of the electromagnetic waves, increasing the propagation path of the electromagnetic waves in the composition, thereby increasing the chance of the electromagnetic waves being absorbed. Copper slag fills the gaps between large-particle-size ferrite-copper slag composite particles, forming a finer microwave-absorbing structure. The two particles form more interfaces, enhancing the reflection and scattering of electromagnetic waves at the interfaces, thereby improving the microwave absorption performance. Moreover, the two particles form a multi-level particle size distribution system. The large-particle-size composite particles act as the scattering center of electromagnetic waves, dispersing the electromagnetic waves to the surrounding small-particle-size copper slag particles, performing initial scattering and absorption of the electromagnetic waves. The small-particle-size particles further absorb the electromagnetic waves after the initial scattering. This allows the electromagnetic waves to be reflected and absorbed multiple times in the material, increasing the microwave absorption bandwidth and reflection loss, and improving the microwave absorption efficiency.

[0016] Optionally, the copper slag and ferrite-copper slag composite are added after being treated with silane coupling agent solution. Specifically, the copper slag and ferrite-copper slag composite are placed in a 25-35% (w / w) 3-aminopropyltriethoxysilane ethanol solution, stirred at 40-50℃ for 40-60 min, and then filtered and dried.

[0017] By adopting the above technical solution, copper slag and ferrite-copper slag composite are impregnated with silane coupling agent solution to form an organic-inorganic interface layer on the particle surface. With minimal impact on microwave absorption performance, the amino groups in the silane coupling agent can undergo complexation reaction with calcium ions in cement hydration products, improving the compatibility of copper slag and ferrite-copper slag composite with cement, enhancing the interfacial bonding between particles and cement, and helping to form a more uniform microwave absorption structure.

[0018] Optionally, the modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler is prepared by the following method: Carbon fibers are treated in a nitric acid solution with a mass concentration of 55-65 wt% for 20-40 minutes at a temperature of 70-80℃, and then cooled to obtain pretreated carbon fibers. Polyvinyl alcohol and water were mixed at a mass ratio of 1:(3-4), and then mica powder-modified waste adhesive powder composite filler was added. After mixing, the mixture was coated onto pretreated carbon fibers and dried to obtain modified carbon fibers loaded with mica powder-modified waste adhesive powder composite filler. The amount of polyvinyl alcohol added is 3-5 wt% of the pretreated carbon fiber, and the mass ratio of mica powder-modified waste rubber powder composite filler to pretreated fiber is 1:(2-3).

[0019] By adopting the above technical solutions, the addition of PE fibers in this application significantly improves the ductility of the cement composition, while the addition of carbon fibers can further improve the ductility of the cement-based composite material, play a bridging role, and inhibit crack propagation. Moreover, the carbon fibers in this application have good electrical conductivity and can serve as a transmission channel for electromagnetic waves, making it easier for electromagnetic waves to enter the interior of the material and be absorbed by copper slag and ferrite-copper slag composites, thereby promoting the transmission loss of electromagnetic waves in the matrix. Ultimately, this application improves the overall performance of the cement composition in terms of wave absorption and ductility through the combination of modified carbon fibers and PE fibers.

[0020] Optionally, the mica powder-modified waste adhesive powder composite filler is prepared by the following method: 1) Dissolve waste rubber powder in toluene, add maleic anhydride and benzoyl peroxide, heat to 65-80℃, react for 2-3 hours, cool and filter to obtain the initial mixture; 2) Dissolve aminosilane coupling agent and PAMAM in ethanol solution, then add the initial mixture and react at 65-75℃ for 40-60 min, then add hydroxyl silicone oil, continue to react for 60-90 min, cool and filter, and dry to obtain modified waste rubber powder. 3) Mix mica powder and modified waste adhesive powder and then disperse them in sodium dodecyl sulfate solution to obtain a suspension. Then dry the suspension and hot press it at 150-170℃ and 8-12MPa, and then crush it to obtain mica powder-modified waste adhesive powder composite filler.

[0021] While the addition of carbon fiber can improve the microwave absorption performance of cement compositions by adopting the above technical solutions, its high modulus easily leads to brittle fracture. Therefore, this application loads a mica powder-modified waste rubber powder composite filler on its surface. In the composite filler, the waste rubber powder is first polymerized with maleic anhydride under the action of an initiator. The unsaturated double bonds in the waste rubber powder are used to polymerize with maleic anhydride, introducing carboxyl functional groups. Then, it is modified by an aminosilane coupling agent and PAMAM. The aminosilane coupling agent bonds with the hydroxyl groups on the surface of the waste rubber powder through siloxane groups, and its amino groups bond with... The introduced carboxyl groups form chemical bonds, and PAMAM can also bond with the carboxyl groups introduced on the surface of waste adhesive powder through amino groups, introducing more amino groups. This can improve its compatibility with cementitious materials. Then, it reacts with hydroxyl silicone oil. The hydroxyl groups in the hydroxyl silicone oil react with amino and carboxyl groups to form chemical bonds. The introduction of hydroxyl silicone oil further improves the ductility of the composite filler. Moreover, hydroxyl silicone oil can also reduce the surface tension of cement paste and increase its fluidity. This can further improve the influence of particles such as copper slag on fluidity, and finally produce a cement composition with better comprehensive performance.

[0022] Finally, mica powder and modified waste rubber powder are mixed and dispersed in sodium dodecyl sulfate solution to form a suspension, which helps to uniformly disperse the two. Then, hot pressing is performed to partially melt the waste rubber powder and fill the interlayer of mica powder to form a composite. In addition, the layered structure of mica powder causes multiple reflections and scatterings between the layers when electromagnetic waves propagate inside, increasing the propagation path of electromagnetic waves in the material and increasing the probability of absorption. Finally, when mica powder-modified waste rubber powder composite particles are loaded on carbon fibers, not only is the brittleness of carbon fibers reduced and the ductility of cement composition improved, but the wave absorption performance is also further improved.

[0023] Optionally, in the preparation process of mica powder-modified waste rubber powder composite filler, in step 1), the ratio of waste rubber powder to maleic anhydride is 1:(0.3-0.4), and the amount of benzoyl peroxide added is 0.5-3 wt% of the amount of waste rubber powder added. In step 2), the mass ratio of aminosilane coupling agent to PAMAM is 1:(0.2-0.4), and the mass ratio of aminosilane coupling agent to the initial mixture is 1:(3-4). The amount of hydroxyl silicone oil added is 1-3 wt% of the initial mixture. In step 3), the mass ratio of mica powder to modified waste rubber powder is 1:(0.8-0.9).

[0024] Optionally, the additives include polycarboxylate superplasticizer and sodium dodecylbenzenesulfonate in a mass ratio of 1:(1.8-2.2).

[0025] By adopting the above technical solution, sodium dodecylbenzenesulfonate, as an anionic surfactant, dissociates into negatively charged ions in water. These ions can be adsorbed on the surface of copper slag and ferrite-copper slag composite particles, making the particle surface negatively charged. Since cement particles are usually also negatively charged, the electrostatic repulsion between particles increases, thereby preventing particle agglomeration and improving dispersibility. At the same time, surfactant molecules can form a lubricating film between particles and cement aggregates, improving compatibility. By improving particle dispersibility, electromagnetic waves can be more uniformly propagated and absorbed in the cement composition, which helps to improve wave absorption performance.

[0026] Secondly, this application provides a method for preparing a highly ductile cement-based composition with microwave absorption properties, using the following technical solution: A method for preparing a highly ductile cement-based composition with microwave absorption properties includes the following steps: mixing cement, sand, copper slag, ferrite-copper slag composite, fly ash and mineral powder, then adding modified carbon fiber and PE fiber loaded with mica powder-modified waste adhesive powder composite filler and stirring to obtain a preliminary mixture; The additive is mixed with water, then the initial mixture is added and stirred to obtain the final product.

[0027] In summary, this application has the following beneficial effects: 1. The copper slag in the cement-based composition of this application contains iron compounds, especially iron(III) oxide, which is both a magnetic and an electrical material and has both magnetic and electrical absorption functions. Therefore, it can be used to replace sand as an aggregate in the cement-based composition, realizing the resource utilization of waste, reducing copper slag emissions, reducing the pressure on the environment, and the iron oxide compound in it acts as a wave-absorbing material, so that the cement-based composition has wave-absorbing properties. 2. The iron-containing electroplating sludge in this application contains metallic elements such as iron and copper. These iron oxides have magnetic and dielectric loss characteristics, which can absorb electromagnetic waves, providing a basis for its use as a microwave absorbing material. After mixing with iron sludge and adding water, iron salts are added to supplement the iron source. Then, it is mixed with copper slag and calcium oxide and subjected to high-temperature oxidation treatment, allowing the iron-containing substances to be better oxidized to form ferrite containing iron(III) oxide. Furthermore, elements such as nickel in the iron-containing electroplating sludge dope the iron oxide during the process, adjusting its electromagnetic parameters to achieve wider-band electromagnetic wave absorption. The addition of calcium oxide helps to achieve the ferrite formation reaction and can reduce copper content. The ferroolitic structure in the slag promotes the release of ferrous oxide, which is conducive to the formation of ferrite. After high-temperature oxidation treatment, the low-valence iron in copper slag and iron-containing electroplating sludge is oxidized to high-valence iron, thereby enhancing magnetic loss and dielectric loss. It can also promote the crystallization of iron oxide, making its grain size and morphology more uniform, which is beneficial to improving the microwave absorption performance. It can also remove some impurities in copper slag and iron-containing electroplating sludge, reducing the negative impact on microwave absorption performance. Finally, it was found that the use of ferrite-copper slag composite significantly improves its microwave absorption performance compared with copper slag alone. The cement-based composition prepared has good microwave absorption performance. Detailed Implementation

[0028] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0029] In the following examples, the cement used is P.O42.5 ordinary Portland cement; the fly ash is Grade II fly ash, the mineral powder is Grade S95 mineral powder, the sand is sand with a fineness modulus of 2.5-3.2, and the polycarboxylate superplasticizer is polycarboxylate superplasticizer from Shandong Jinrong Chemical Technology Co., Ltd. The copper slag contains 22.54% iron by mass, 1.45% copper by mass, and the remainder consists of zinc, aluminum, silicon, and other elements.

[0030] Iron-containing electroplating sludge is the electroplating waste generated during the electroplating process with added compounds such as ferrous sulfate or ferrous chloride, as well as the product formed by precipitation after adding iron salts to adjust the pH value and adding flocculants to electroplating wastewater. In the following examples, the mass percentage of iron in the iron-containing electroplating sludge is 15.68%, the mass percentage of nickel is 13.47%, and the balance is copper and other elements.

[0031] The hydroxyl silicone oil used in the following preparation examples has a hydroxyl content of 10% and a viscosity (25℃, mm). 2 / S) is 30 mm 2 / S Hydroxy silicone oil.

[0032] The following preparation examples are examples of the preparation of ferrite-copper slag composites.

[0033] Preparation Example 1 A method for preparing a ferrite-copper slag composite includes the following steps: The iron-containing electroplating sludge is dried to a moisture content of less than 1%, then crushed into sludge particles of 1-3 mm, mixed with ferrous sulfate, and then water is added. The mixture is stirred at 250 r / min for 15 min to form a slurry. The amount of ferrous sulfate added is 8 wt% of the sludge particles, and the mass ratio of sludge particles to water is 1:3.5. Then, copper slag with a particle size of 1.5-2.36 mm and calcium oxide were added to the slurry and stirred at 400 r / min for 20-30 min to obtain a mixture. The mass ratio of sludge particles to copper slag was 1:2.5, and the amount of calcium oxide added was 2 wt% of the amount of copper slag added. The mixture was then heated to 900°C at a heating rate of 8°C / min, treated in air for 3 hours, cooled to room temperature, and crushed to obtain a 0.5-3 mm ferrite-copper slag composite.

[0034] Preparation Example 2 A method for preparing a ferrite-copper slag composite includes the following steps: The iron-containing electroplating sludge is dried to a moisture content of less than 1%, then crushed into sludge particles of 1-3 mm, mixed with ferrous sulfate, and then water is added. The mixture is stirred at 200 r / min for 20 min to form a slurry. The amount of ferrous sulfate added is 5 wt% of the sludge particles, and the mass ratio of sludge particles to water is 1:3. Then, copper slag with a particle size of 1.5-2.36 mm and calcium oxide were added to the slurry and stirred at 300 r / min for 30 min to obtain a mixture. The mass ratio of sludge particles to copper slag was 1:2, and the amount of calcium oxide added was 1 wt% of the amount of copper slag added. The mixture was then heated to 800°C at a heating rate of 5°C / min, treated in air for 4 hours, cooled to room temperature, and crushed to obtain a 0.5-3 mm ferrite-copper slag composite.

[0035] Preparation Example 3 A method for preparing a ferrite-copper slag composite includes the following steps: The iron-containing electroplating sludge is dried to a moisture content of less than 1%, then crushed into sludge particles of 1-3 mm, mixed with ferrous sulfate, and then water is added. The mixture is stirred at 300 r / min for 10 min to form a slurry. The amount of ferrous sulfate added is 12 wt% of the sludge particles, and the mass ratio of sludge particles to water is 1:4. Then, copper slag with a particle size of 1.5-2.36 mm and calcium oxide were added to the slurry and stirred at 500 r / min for 20 min to obtain a mixture. The mass ratio of sludge particles to copper slag was 1:3, and the amount of calcium oxide added was 3 wt% of the amount of copper slag. The mixture was then heated to 1000℃ at a heating rate of 10℃ / min, treated in air for 2 hours, cooled to room temperature, and crushed to obtain a ferrite-copper slag composite of 0.5-3mm.

[0036] Comparative Preparation Example 1 A method for preparing a ferrite-copper slag composite is carried out according to the method in Preparation Example 1, except that calcium oxide is not added to the slurry.

[0037] The following preparation examples are examples of the preparation of modified carbon fibers loaded with mica powder-modified waste rubber powder composite filler.

[0038] Preparation Example 4 A method for preparing modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler includes the following steps: S1. The carbon fiber was treated in a 60wt% nitric acid solution for 30 minutes at a temperature of 75℃, and then cooled to obtain pretreated carbon fiber. The mass ratio of carbon fiber to nitric acid solution was 1:9. S2. Preparation of mica powder-modified waste adhesive powder composite filler, specifically including the following steps: 1) Dissolve waste rubber powder in 3 times its mass of toluene, add maleic anhydride and benzoyl peroxide, heat to 70℃, react for 2.5 h, cool and filter to obtain a preliminary mixture. The ratio of waste rubber powder to maleic anhydride is 1:0.3, and the amount of benzoyl peroxide added is 1.5 wt% of the amount of waste rubber powder. 2) The aminosilane coupling agent KH-550 and PAMAM were mixed at a mass ratio of 1:0.3 and dissolved in an ethanol solution (ethanol and water were mixed at a mass ratio of 1:1.2). This solution was then added to the initial mixture obtained in step 1) and reacted at 70°C for 50 minutes. Hydroxy silicone oil was then added, and the reaction continued for 75 minutes. After cooling and filtration, the mixture was dried to obtain modified waste rubber powder. The mass ratio of aminosilane coupling agent to the initial mixture was 1:3.5, and the amount of hydroxy silicone oil added was 2 wt% of the initial mixture. 3) Mix mica powder and modified waste adhesive powder at a mass ratio of 1:0.8 and then disperse them in sodium dodecyl sulfate solution (sodium dodecyl sulfate and water are mixed at a mass ratio of 1:12) to obtain a suspension. Then, dry the suspension and hot press it at 160℃ and 10MPa, and then crush it to obtain the mica powder-modified waste adhesive powder composite filler. S3. Polyvinyl alcohol and water are mixed at a mass ratio of 1:3.5, and then mica powder-modified waste adhesive powder composite filler is added. After mixing, the mixture is coated onto the pretreated carbon fiber and dried and cured at 80°C to obtain modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler. The amount of polyvinyl alcohol added is 4 wt% 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.

[0039] Preparation Example 5 A method for preparing modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler includes the following steps: S1. The carbon fiber was treated in a 55wt% nitric acid solution for 40 minutes at a temperature of 70°C, and then cooled to obtain pretreated carbon fiber. The mass ratio of carbon fiber to nitric acid solution was 1:8. S2. Preparation of mica powder-modified waste adhesive powder composite filler, specifically including the following steps: 1) Dissolve waste rubber powder in toluene at a mass ratio of 2, add maleic anhydride and benzoyl peroxide, heat to 65°C, react for 3 hours, cool and filter to obtain a preliminary mixture. The ratio of waste rubber powder to maleic anhydride is 1:0.3, and the amount of benzoyl peroxide added is 0.5 wt% of the amount of waste rubber powder. 2) The aminosilane coupling agent KH-550 and PAMAM were mixed at a mass ratio of 1:0.2 and dissolved in an ethanol solution (ethanol and water were mixed at a mass ratio of 1:1.2). This solution was then added to the initial mixture obtained in step 1) and reacted at 65°C for 60 minutes. Hydroxy silicone oil was then added, and the reaction continued for another 60 minutes. After cooling and filtration, the mixture was dried to obtain modified waste rubber powder. The mass ratio of aminosilane coupling agent to the initial mixture was 1:3, and the amount of hydroxy silicone oil added was 1 wt% of the initial mixture. 3) Mix mica powder and modified waste rubber powder at a mass ratio of 1:0.8 and then disperse them in sodium dodecyl sulfate solution (sodium dodecyl sulfate and water are mixed at a mass ratio of 1:12) to obtain a suspension. Then, dry the suspension and hot press it at 150℃ and 8MPa, and then crush it to obtain mica powder-modified waste rubber powder composite filler. S3. Polyvinyl alcohol and water are mixed at a mass ratio of 1:3, and then mica powder-modified waste adhesive powder composite filler is added. After mixing, the mixture is coated onto the pretreated carbon fiber and dried and cured at 80°C to obtain modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler. The amount of polyvinyl alcohol added is 3 wt% of the pretreated carbon fiber, and the mass ratio of mica powder-modified waste rubber powder composite filler to pretreated fiber is 1:2.

[0040] Preparation Example 6 A method for preparing modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler includes the following steps: S1. The carbon fiber was treated in a 65wt% nitric acid solution for 20 minutes at a temperature of 80℃, and then cooled to obtain pretreated carbon fiber. The mass ratio of carbon fiber to nitric acid solution was 1:8. S2. Preparation of mica powder-modified waste adhesive powder composite filler, specifically including the following steps: 1) Dissolve waste rubber powder in 4 times its mass of toluene, add maleic anhydride and benzoyl peroxide, heat to 80℃, react for 2 hours, cool and filter to obtain a preliminary mixture. The ratio of waste rubber powder to maleic anhydride is 1:0.4, and the amount of benzoyl peroxide added is 3 wt% of the amount of waste rubber powder. 2) The aminosilane coupling agent KH-550 and PAMAM were mixed at a mass ratio of 1:0.4 and dissolved in an ethanol solution (ethanol and water were mixed at a mass ratio of 1:1.2). The mixture was then added to the initial mixture obtained in step 1) and reacted at 75°C for 40 minutes. Hydroxy silicone oil was then added, and the reaction continued for 90 minutes. After cooling and filtration, the mixture was dried to obtain modified waste rubber powder. The mass ratio of aminosilane coupling agent to the initial mixture was 1:4, and the amount of hydroxy silicone oil added was 3 wt% of the initial mixture. 3) Mix mica powder and modified waste rubber powder at a mass ratio of 1:0.9 and then disperse them in sodium dodecyl sulfate solution (sodium dodecyl sulfate and water are mixed at a mass ratio of 1:12) to obtain a suspension. Then, dry the suspension and hot press it at 170℃ and 12MPa, and then crush it to obtain mica powder-modified waste rubber powder composite filler. S3. Polyvinyl alcohol and water are mixed at a mass ratio of 1:4, and then mica powder-modified waste adhesive powder composite filler is added. After mixing, the mixture is coated onto the pretreated carbon fiber and dried and cured at 80°C to obtain modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler. The amount of polyvinyl alcohol added is 5 wt% of the pretreated carbon fiber, and the mass ratio of mica powder-modified waste rubber powder composite filler to pretreated fiber is 1:3.

[0041] Comparative Preparation Example 2 A method for preparing modified carbon fiber is carried out according to the method in Preparation Example 4, except that step S2 is not performed, and in step S3, the mica powder-modified waste adhesive powder composite filler is replaced with an equal amount of mica powder.

[0042] Comparative preparation example 3 A method for preparing modified carbon fiber is carried out according to the method in Preparation Example 4, except that step S2 is not performed, and in step S3, the mica powder-modified waste rubber powder composite filler is replaced with waste rubber powder in equal amounts.

[0043] Example 1

[0044] A method for preparing a highly ductile cement-based composition with microwave absorbing properties includes the following steps: 300 parts of cement, 480 parts of sand, 300 parts of copper slag with a particle size of 0.15-1.5 mm, 200 parts of ferrite-copper slag composite with a particle size of 0.5-3 mm prepared in Preparation Example 1, 40 parts of fly ash and 25 parts of mineral powder were mixed, and then 15 parts of modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler prepared in Preparation Example 4 and 22 parts of PE fiber were added and stirred to obtain a preliminary mixture. Two parts of additive were mixed with 180 parts of water, and then the initial mixture was added and stirred to obtain the additive, which included polycarboxylate superplasticizer and sodium dodecylbenzenesulfonate in a mass ratio of 1:2.

[0045] The cement-based composition prepared in Example 1 has a continuous effective bandwidth of 9.4 GHz with a minimum reflectivity of -10 dB in the frequency range of 2.0-18.0 GHz.

[0046] Example 2

[0047] A method for preparing a highly ductile cement-based composition with microwave absorbing properties includes the following steps: 250 parts of cement, 450 parts of sand, 280 parts of copper slag with a particle size of 0.15-1.5 mm, 170 parts of ferrite-copper slag composite with a particle size of 0.5-3 mm prepared in Preparation Example 2, 30 parts of fly ash and 15 parts of mineral powder were mixed, and then 10 parts of modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler prepared in Preparation Example 5 and 15 parts of PE fiber were added and stirred to obtain a preliminary mixture. One part of the additive is mixed with 150 parts of water, and then added to the initial mixture and stirred to obtain the additive, which includes polycarboxylate superplasticizer and sodium dodecylbenzenesulfonate in a mass ratio of 1:1.8.

[0048] The cement-based composition prepared in Example 2 has a continuous effective bandwidth of 9.0 GHz with a value below -10 dB in the frequency range of 2.0-18.0 GHz, and a minimum reflectivity of -18.6 dB.

[0049] Example 3

[0050] A method for preparing a highly ductile cement-based composition with microwave absorbing properties includes the following steps: 350 parts of cement, 520 parts of sand, 320 parts of copper slag with a particle size of 0.15-1.5 mm, 230 parts of ferrite-copper slag composite with a particle size of 0.5-3 mm prepared in Preparation Example 3, 50 parts of fly ash and 40 parts of mineral powder were mixed, and then 20 parts of modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler prepared in Preparation Example 6 and 30 parts of PE fiber were added and stirred to obtain a preliminary mixture. After mixing 3 parts of additive with 240 parts of water, the initial mixture was added and stirred to obtain the additive, which included polycarboxylate superplasticizer and sodium dodecylbenzenesulfonate in a mass ratio of 1:2.2.

[0051] The cement-based composition prepared in Example 3 has a continuous effective bandwidth of 9.1 GHz with a minimum reflectivity of -10 dB within the frequency range of 2.0-18.0 GHz.

[0052] Example 4

[0053] A method for preparing a highly ductile cement-based composition with microwave absorption properties is carried out according to the method in Example 1, except that copper slag and ferrite-copper slag composite are added after being treated with silane coupling agent solution. Specifically, the copper slag and ferrite-copper slag composite are placed in a 30% mass concentration 3-aminopropyltriethoxysilane ethanol solution (the ethanol solution is 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.

[0054] The cement-based composition prepared in this embodiment has a continuous effective bandwidth of 9.9 GHz with a minimum reflectivity of -10 dB in the frequency range of 2.0-18.0 GHz and a minimum reflectivity of -23.7 dB.

[0055] Example 5

[0056] A method for preparing a highly ductile cement-based composition with microwave absorption properties is carried out according to the method in Example 1, except that copper slag and ferrite-copper slag composite are added after being treated with silane coupling agent solution. Specifically, the copper slag and ferrite-copper slag composite are placed in a 25% mass concentration 3-aminopropyltriethoxysilane ethanol solution (the ethanol solution is 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.

[0057] The cement-based composition prepared in this embodiment has a continuous effective bandwidth of 9.6 GHz with a minimum reflectivity of -10 dB within the frequency range of 2.0-18.0 GHz.

[0058] Example 6

[0059] A method for preparing a highly ductile cement-based composition with microwave absorption properties is carried out according to the method in Example 1, except that copper slag and ferrite-copper slag composite are added after being treated with silane coupling agent solution. Specifically, the copper slag and ferrite-copper slag composite are placed in a 35% mass concentration 3-aminopropyltriethoxysilane ethanol solution (the ethanol solution is prepared by mixing ethanol and water in a mass ratio of 1:1), stirred at 50°C for 60 min, and then filtered and dried.

[0060] The cement-based composition prepared in this embodiment has a continuous effective bandwidth of 9.8 GHz with a minimum reflectivity of -10 dB within the frequency range of 2.0-18.0 GHz.

[0061] Example 7

[0062] A method for preparing a highly ductile cementitious composition with microwave absorption properties is carried out according to the method in Example 1, except that a polycarboxylate superplasticizer is selected as the admixture.

[0063] The cement-based composition prepared in this embodiment has a continuous effective bandwidth of 8.4 GHz with a minimum reflectivity of -10 dB within the frequency range of 2.0-18.0 GHz.

[0064] Comparative Example 1 A method for preparing a highly ductile cement-based composition with microwave absorption properties is carried out according to the method in Example 1, except that the ferrite-copper slag composite is selected from the ferrite-copper slag composite prepared in Comparative Preparation Example 1.

[0065] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 7.5 GHz with a minimum reflectivity of -10 dB in the frequency range of 2.0-18.0 GHz, which is below -10 dB.

[0066] Comparative Example 2 A method for preparing a highly ductile cement-based composition with microwave absorption properties is carried out according to the method in Example 1, except that the ferrite-copper slag composite is replaced in equal amounts with copper slag with a particle size of 0.15-1.5 mm.

[0067] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 5.6 GHz with a minimum reflectivity of -10 dB in the frequency range of 2.0-18.0 GHz, which is below -10 dB.

[0068] Comparative Example 3 A method for preparing a highly ductile cement-based composition with microwave absorption properties is carried out according to the method in Example 1, except that the ferrite copper slag composite is replaced in equal amounts with 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 sludge particles to copper slag is 1:2.5. The sludge particles are dried from iron-containing electroplating sludge to a moisture content of less than 1%, and then crushed into sludge particles of 1-3 mm.

[0069] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 5.2 GHz with a minimum reflectivity of -10 dB in the frequency range of 2.0-18.0 GHz, which is below -10 dB.

[0070] Comparative Example 4 A method for preparing a highly ductile cement-based composition with wave-absorbing properties is carried out according to the method in Example 1, except that the modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler is replaced with an equal amount of carbon fiber.

[0071] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 6.3 GHz with a minimum reflectivity of -10 dB in the frequency range of 2.0-18.0 GHz, which is below -10 dB.

[0072] Comparative Example 5 A method for preparing a highly ductile cement-based composition with wave-absorbing properties is carried out according to the method in Example 1, except that the modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler is replaced in equal amounts with the modified carbon fiber prepared in Comparative Preparation Example 2.

[0073] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 8.8 GHz with a minimum reflectivity of -10 dB in the frequency range of 2.0-18.0 GHz.

[0074] Comparative Example 6 A method for preparing a highly ductile cement-based composition with wave-absorbing properties is carried out according to the method in Example 1, except that the modified carbon fiber loaded with mica powder-modified waste adhesive powder composite filler is replaced in equal amounts with the modified carbon fiber prepared in Comparative Preparation Example 3.

[0075] The cement-based composition prepared in this comparative example has a continuous effective bandwidth of 6.8 GHz with a minimum reflectivity of -10 dB in the frequency range of 2.0-18.0 GHz, which is below -10 dB.

[0076] Performance testing The cement-based composite materials prepared in the embodiments and comparative examples of this application were subjected to ultimate tensile testing according to JC / T 2461-2018 "Test Method for Mechanical Properties of High-Ductility Fiber Reinforced Cement-Based Composite Materials" to characterize their ductility properties. The test results are shown in Table 1 below.

[0077] Table 1:

[0078] Referring to Table 1 above and the test results of the examples and comparative examples regarding microwave absorption performance, it can be seen that the cement-based composition prepared in the examples has both excellent ductility and good microwave absorption performance. Combining the test results of Examples 1 and 4-6, it can be seen that adding copper slag and ferrite-copper slag composites after treatment with silane coupling agents helps their dispersion and compatibility in the cement matrix, further improving both microwave absorption performance and mechanical properties. Furthermore, considering the test results of Example 7, when only polycarboxylate superplasticizer was added as an admixture in Example 7, the microwave absorption performance decreased.

[0079] Referring to the test results of Example 1 and Comparative Example 1, the addition of calcium oxide during the preparation of the ferrite-copper slag composite affects the crystal structure of both materials, significantly improving their microwave absorption performance. Combining this with the test results of Comparative Example 2, the microwave absorption performance is significantly reduced when only copper slag is added and no ferrite-copper slag composite is added to the raw materials. The addition of the ferrite-copper slag composite significantly improves its microwave absorption performance. Combining this with the test results of Comparative Example 3, the microwave absorption performance is significantly reduced compared to Example 1 when only iron-containing electroplating sludge particles and copper slag are added to the raw materials. High-temperature oxidation treatment significantly improves its microwave absorption performance. Combining this with the test results of Comparative Example 4, the microwave absorption performance is also reduced when unmodified carbon fiber is added directly. The addition of mica powder helps to further improve the microwave absorption performance. Based on the test results of Example 1 and Comparative Example 5, when the composite filler loaded on the carbon fiber in Comparative Example 5 was replaced with mica powder and no waste adhesive powder was added, its ductility was significantly reduced. Based on the test results of Comparative Example 6, when the carbon fiber was only loaded with waste adhesive powder and not with mica powder, its wave absorption performance was reduced.

[0080] Furthermore, the 28-day compressive strength of the cement-based compositions prepared in Examples 1-6 of this application is 45.8-49.7 MPa, and its fluidity is 150-170 mm (the fluidity was determined in accordance with GB 2419-2005 "Method for Determination of Flowability of Cement Mortar").

[0081] In addition, the cement-based compositions prepared in Examples 1 and 4 were tested for 28-day compressive strength, tensile strength and peak strain. The test results are shown in Table 2 below.

[0082] Table 2:

[0083] Based on the test results in Table 2 above, it can be seen that the cement-based composition prepared in this application has excellent ductility as well as excellent mechanical properties.

[0084] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A highly ductile cement-based composition with microwave absorbing properties, characterized in that, Including the following parts by weight of raw materials: 250-350 parts cement, 450-520 parts sand, 150-240 parts water, 280-320 parts copper slag, 170-230 parts ferrite-copper slag composite, 30-50 parts fly ash, 15-40 parts mineral powder, 1-3 parts admixtures, 10-20 parts modified carbon fiber loaded with mica powder-modified waste rubber powder composite filler, and 15-30 parts PE fiber; The ferrite-copper slag composite is prepared by mixing iron-containing electroplating sludge with iron salts and adding water to form a slurry. Copper slag and calcium oxide are added to the slurry and then oxidized in an air atmosphere. After crushing, the ferrite-copper slag composite is obtained.

2. The highly ductile cement-based composition with microwave absorption properties according to claim 1, characterized in that: The ferrite-copper slag composite was prepared by the following method: Iron-containing electroplating sludge is dried and crushed into 1-3 mm sludge particles, then mixed with ferrous sulfate and water, and stirred to form a slurry. Copper slag and calcium oxide with a particle size of 1.5-2.36 mm are then added to the slurry and stirred to obtain a mixture. The mixture is then heated to 800-1000℃ and treated in air for 2-4 hours. After cooling to room temperature, it is crushed to obtain a 0.5-3 mm ferrite-copper slag composite.

3. The highly ductile cement-based composition with microwave absorbing properties according to claim 2, characterized in that: When preparing 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), 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 highly ductile cement-based composition with microwave absorbing properties according to claim 1, characterized in that: The particle size of copper slag in the raw materials of the high ductility cement-based composition is 0.15-1.5 mm.

5. The highly ductile cement-based composition with microwave absorbing properties according to claim 1, characterized in that: The copper slag and ferrite-copper slag composite were added after being treated with silane coupling agent solution. The specific operation was as follows: the copper slag and ferrite-copper slag composite were placed in a 25-35% mass concentration 3-aminopropyltriethoxysilane ethanol solution, stirred at 40-50℃ for 40-60 min, and then filtered and dried.

6. The highly ductile cement-based composition with microwave absorbing properties according to claim 1, characterized in that: Modified carbon fibers loaded with mica powder-modified waste adhesive powder composite filler are prepared by the following method: Carbon fibers are treated in a nitric acid solution with a mass concentration of 55-65 wt% for 20-40 minutes at a temperature of 70-80℃, and then cooled to obtain pretreated carbon fibers. Polyvinyl alcohol and water were mixed at a mass ratio of 1:(3-4), and then mica powder-modified waste adhesive powder composite filler was added. After mixing, the mixture was coated onto pretreated carbon fibers and dried to obtain modified carbon fibers loaded with mica powder-modified waste adhesive powder composite filler. The amount of polyvinyl alcohol added is 3-5 wt% of the pretreated carbon fiber, and the mass ratio of mica powder-modified waste rubber powder composite filler to pretreated fiber is 1:(2-3).

7. The highly ductile cement-based composition with microwave absorbing properties according to claim 1, characterized in that: The mica powder-modified waste adhesive powder composite filler is prepared by the following method: 1) Dissolve waste rubber powder in toluene, add maleic anhydride and benzoyl peroxide, heat to 65-80℃, react for 2-3 hours, cool and filter to obtain the initial mixture; 2) Dissolve aminosilane coupling agent and PAMAM in ethanol solution, then add the initial mixture and react at 65-75℃ for 40-60 min, then add hydroxyl silicone oil, continue to react for 60-90 min, cool and filter, and dry to obtain modified waste rubber powder. 3) Mix mica powder and modified waste adhesive powder and then disperse them in sodium dodecyl sulfate solution to obtain a suspension. Then dry the suspension and hot press it at 150-170℃ and 8-12MPa, and then crush it to obtain mica powder-modified waste adhesive powder composite filler.

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

9. A highly ductile cement-based composition with microwave absorbing properties according to claim 1, characterized in that: The admixtures include polycarboxylate superplasticizer and sodium dodecylbenzenesulfonate in a mass ratio of 1:(1.8-2.2).

10. A method for preparing a highly ductile cementitious composition with microwave absorbing properties as described in any one of claims 1-9, characterized in that: Includes the following steps: After mixing cement, sand, copper slag, ferrite-copper slag composite, fly ash and mineral powder, modified carbon fiber and PE fiber loaded with mica powder-modified waste adhesive powder composite filler are added and stirred to obtain a preliminary mixture. The additive is mixed with water, then the initial mixture is added and stirred to obtain the final product.

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