Ceramsite for metal sound barrier and preparation method thereof

Abstract

The invention relates to the technical field of sound barriers, and particularly discloses ceramsite for a metal sound barrier and a preparation method of the ceramsite. The ceramsite for the metal sound barrier comprises an inner core and a waterproof layer, and the inner core comprises the following materials in parts by weight: 100 parts of fly ash; 20 parts of cement; 8 parts of calcined gypsum; 4 parts of quick lime; 6-8 parts of expanded perlite; 2.5 to 7.5 parts of hydrogen peroxide; the waterproof layer is prepared from a waterproof coating; the waterproof coating comprises the following materials in parts by weight: 5 parts of epoxy resin; 2 parts of PDMS; 1.7 parts of triethylene tetramine; 0.3 part of a curing agent; 0.3 to 0.5 part of titanium dioxide; 35 parts of a solvent; the preparation method comprises the following steps: S1, preparing the inner core; s2, preparing a waterproof coating; s3, ceramsite preparation. The ceramsite can be used in a metal sound barrier, and has the advantages of water resistance, corrosion resistance, high strength and good sound absorption and noise reduction effects.

Description

Technical Field

[0001] This application relates to the technical field of sound barriers, and more specifically, it relates to a type of ceramic aggregate for metal sound barriers and a method for preparing the same. Background Technology

[0002] Sound barriers are a commonly used and effective noise reduction measure. Sound barriers are mainly divided into metal sound barriers and non-metal sound barriers based on their materials. Metal sound barriers are the primary choice due to their lightweight, long lifespan, and aesthetic appeal. The structure of a metal sound barrier consists of a cavity formed by a metal shell, with sound-absorbing material fixed inside to form sound barrier unit panels.

[0003] Expanded clay aggregate (ECA) is a high-performance lightweight aggregate currently mainly used in building backfilling, sewage treatment, and thermal insulation blocks. Due to its light weight, small particle size, and numerous internal microporous structures, ECA is widely used as a sound-absorbing material in sound barriers. However, since metal sound barriers are mostly located in open environments, ECA is easily corroded by rainwater and moisture, leading to poor sound absorption performance. Summary of the Invention

[0004] To improve the durability of ceramsite and the sound absorption effect of sound barriers, this application provides ceramsite for metal sound barriers and its preparation method, adopting the following technical solution:

[0005] In a first aspect, this application provides ceramic aggregate for metal sound barriers, characterized in that it comprises an inner core and a waterproof layer, wherein the inner core comprises the following materials in parts by weight:

[0006] 100 parts fly ash;

[0007] 20 parts cement;

[0008] 8 parts of calcined gypsum;

[0009] 4 parts quicklime;

[0010] 6-8 parts expanded perlite;

[0011] 2.5-7.5 parts hydrogen peroxide;

[0012] 2 parts rice bran;

[0013] The waterproof layer is prepared by a waterproof coating, which comprises the following materials in parts by weight:

[0014] 5 parts epoxy resin;

[0015] Two copies of PDMS;

[0016] 1.7 parts of triethylenetetramine;

[0017] 0.3 parts curing agent;

[0018] 0.3-0.5 parts of titanium dioxide;

[0019] 35 parts solvent.

[0020] By adopting the above technical solution, fly ash, cement, hydrated gypsum, and quicklime are preferably used to prepare ceramsite, giving it lightweight, thermal insulation, and sound absorption / noise reduction properties. Adding expanded perlite to the ceramsite acts as a pore-forming agent, introducing numerous closed pores into the ceramsite. Pores also form between the expanded perlite and the main ceramsite material, increasing the porosity within the ceramsite and thus achieving better sound absorption and noise reduction. Simultaneously, the amount of expanded perlite added is optimized. At an appropriate amount, calcium hydroxide is less likely to be reduced to hydrated calcium carbonate, thereby reducing the possibility of calcium silicate hydrate clogging the pores. Hydrogen peroxide, as a foaming agent, decomposes to produce gas, further creating pores within the ceramsite.

[0021] The preferred method is to use epoxy resin and PDMS to form a composite coating. The introduction of titanium dioxide can give the coating surface a micro-nano structure, which gives the coating better waterproof, corrosion-resistant and self-cleaning effects. This gives the ceramic particles excellent moisture-proof, waterproof, corrosion-resistant, self-cleaning and durable effects, and can play a long-term role in sound absorption and noise reduction in metal sound barriers.

[0022] Optionally, the inner core may also include 3-4 parts by weight of cellulose fiber.

[0023] By adopting the above technical solution, it is preferable to add fibrous carbon to the inner core. Fiber carbon contains a large number of microporous structures. Compared with the closed-cell structure of expanded perlite and the pore structure produced by hydrogen peroxide, the microporous structure in fiber carbon is smaller in size. Therefore, it can form a graded pore structure inside the ceramic particles, so that the ceramic particles can absorb and shield noise of multiple bands, effectively improving the sound absorption and noise reduction effect of the metal sound barrier.

[0024] Optionally, the fiber charcoal is prepared as follows: waste bio-fiber charcoal is crushed, placed in a tube furnace for pyrolysis, and ground to obtain fiber charcoal.

[0025] By adopting the above technical solution, the waste bio-cellulose char can be crushed, pyrolyzed and ground to remove the coating material on the surface of the bio-cellulose char, expose the pore structure on the surface of the char, increase the specific surface area of ​​the char, improve the bonding effect between the char and other components of the ceramsite, and improve the mechanical strength and sound absorption effect of the ceramsite.

[0026] Optionally, the titanium dioxide is titanium dioxide modified with a titanate coupling agent.

[0027] By adopting the above technical solution, it is preferable to use a titanate coupling agent to modify titanium dioxide, which can improve the surface energy of titanium dioxide, enabling titanium dioxide to be uniformly dispersed in the waterproof coating, thereby giving the ceramic particle surface a uniform waterproof effect and a self-cleaning effect.

[0028] Optionally, the waterproof coating may also include 1-2 parts of polyurethane.

[0029] By adopting the above technical solution, polyurethane is added to the waterproof coating. Polyurethane itself has a relatively good damping effect. When added to the waterproof coating, it can give the ceramsite a damping and noise reduction effect. This allows the ceramsite to reduce noise not only through its multi-stage pore structure, but also through damping, thereby further improving the sound absorption and noise reduction effect of the ceramsite.

[0030] Optionally, the polyurethane is an epoxy resin modified polyurethane.

[0031] By adopting the above technical solution, epoxy resin is preferably used to modify polyurethane. Epoxy resin can form an interpenetrating network structure with polyurethane, which not only further improves the damping and noise reduction function of polyurethane but also enhances the bonding effect between the waterproof coating and the core, ensuring stable and excellent waterproof performance of the ceramsite. Simultaneously, the grafting of epoxy resin further improves the compatibility between polyurethane and the waterproof coating, and increases the density of the waterproof coating, thereby further improving both the waterproof and noise reduction effects.

[0032] Optionally, the epoxy resin modified polyurethane is prepared as follows: take polyether polyol, dehydrate it, add TDI, stir and react to obtain polyurethane prepolymer; heat the epoxy resin to reduce its viscosity, add a catalyst and the polyurethane prepolymer, and defoam under vacuum to obtain epoxy resin modified polyurethane.

[0033] Secondly, this application provides a method for preparing ceramsite for metal sound barriers, employing the following technical solution:

[0034] A method for preparing ceramsite for metal sound barriers includes the following steps:

[0035] S1. Inner core preparation: Take fly ash, cement, quicklime, slaked lime, expanded perlite, rice husk, hydrogen peroxide and water, stir and granulate, cure to obtain the inner core;

[0036] S2. Preparation of waterproof coating: Dissolve epoxy resin and PDMS in a solvent, add triethylenetetramine, curing agent and titanium dioxide, stir, and prepare waterproof coating;

[0037] S3. Preparation of ceramsite: Waterproof coating is sprayed on the outside of the inner core and dried to obtain ceramsite.

[0038] By adopting the above technical solutions, and preferably using a non-fired method to prepare ceramsite, energy consumption can be greatly reduced, the operation is simpler, and there are high economic benefits.

[0039] Optionally, the curing in step S1 is autoclaving.

[0040] By adopting the above technical solution, the steam curing treatment of ceramsite can promote the hydration reaction inside the ceramsite, producing hydration products such as tobermorite and CSH gel with high crystallinity, making the ceramsite more compact, ensuring the strength of the ceramsite, and facilitating the control of the pore size inside the ceramsite.

[0041] Optionally, in step S3, the inner core is pre-mixed with ammonium acetate sprayed with water, filtered, and dried to obtain a pre-treated inner core. Then, a waterproof coating is sprayed on the outside of the pre-treated inner core, heated, and dried to prepare ceramsite.

[0042] By adopting the above technical solution, the core is mixed with ammonium acetate in advance. The ammonium acetate fills the surface pores of the core, reducing the possibility of the waterproof coating filling the surface pores of the core. After the waterproof coating is sprayed, it is heated. The ammonium acetate decomposes under heat and produces gas, which can not only impact the blocked pores inside the ceramic particles, but also blow away the waterproof coating adhering to the surface pores of the core, so that the surface of the ceramic particles maintains a better number of pores, that is, maintain the sound absorption effect of the ceramic particles.

[0043] In summary, this application has the following beneficial effects:

[0044] 1. This application uses fly ash, cement, calcined gypsum, and quicklime to prepare ceramsite, resulting in lightweight, thermal insulation, and sound absorption / noise reduction properties. Adding expanded perlite to the ceramsite, which acts as a pore-forming agent, introduces numerous closed pores into the ceramsite. Pores also form between the expanded perlite and the main ceramsite material, increasing the porosity within the ceramsite and thus enhancing its sound absorption and noise reduction effect. Simultaneously, the optimized amount of expanded perlite prevents calcium hydroxide from being reduced to hydrated calcium carbonate, reducing the likelihood of calcium silicate hydrate clogging the pores. Hydrogen peroxide, acting as a foaming agent, decomposes to generate gas, further contributing to the formation of pores within the ceramsite.

[0045] 2. In this application, it is preferred to add fibrous carbon to the inner core. Fiber carbon contains a large number of microporous structures. Compared with the closed-cell structure of expanded perlite and the pore structure produced by hydrogen peroxide, the microporous structure in fiber carbon is smaller in size. Therefore, it can form a graded pore structure inside the ceramsite, so that the ceramsite can absorb and shield noise of multiple bands, effectively improving the sound absorption and noise reduction effect of the metal sound barrier.

[0046] 3. This application adds polyurethane to the waterproof coating. Polyurethane itself has a relatively good damping effect. Adding it to the waterproof coating can give the ceramsite a damping and noise reduction effect, so that the ceramsite can not only reduce noise through the multi-stage pore structure, but also reduce noise through damping, thereby further improving the sound absorption and noise reduction effect of the ceramsite. Detailed Implementation

[0047] The present application will be further described in detail below with reference to the embodiments.

[0048] Preparation Example

[0049] Example of Fiber Carbon Preparation

[0050] Preparation Example 1

[0051] Waste bio-cellulose char was crushed, placed in a tube furnace for pyrolysis at 800°C under a nitrogen atmosphere, and then ground to obtain cellulose char.

[0052] Example of preparation of modified titanium dioxide

[0053] Preparation Example 2

[0054] Take 5g of titanium dioxide and disperse it in 100mL of ethanol aqueous solution (volume ratio: ethanol: water = 9:1). Add 0.25g of titanate coupling agent (YM-2P; pyrophosphate type titanate, Sinopharm Chemical Reagent Co., Ltd.). Add acetic acid to adjust the pH value to 4. Heat the mixture to 80℃ and react for 4h. Centrifuge the reactants, precipitate, wash, and dry at 80℃ for 10h to obtain modified titanium dioxide.

[0055] Preparation example of modified polyurethane

[0056] Preparation Example 3

[0057] Take 78.1g of polyether polyol (PPG), dehydrate it under vacuum at 120℃ for 2-3h, cool it to 50℃ and hold for 30min, add 21.9g of TDI, stir, and heat it to 80℃ to react for 3h to obtain polyurethane prepolymer; heat 50g of epoxy resin at 80℃ for 30min to reduce viscosity, add 1g of catalyst (T12, Jiaqian Chemical Co., Ltd.) and 100g of polyurethane prepolymer, and defoam under vacuum to obtain epoxy resin modified polyurethane.

[0058] Example

[0059] Examples 1-3

[0060] On one hand, this application provides ceramsite for metal sound barriers, including an inner core and a waterproof layer. The inner core comprises the following materials: fly ash (Grade II fly ash), cement (ordinary silicate cement with P·O 42.5), calcined gypsum, quicklime, rice husk, expanded perlite (average particle size of 0.024μm-0.032μm), and hydrogen peroxide, with specific quantities shown in the table below. The waterproof layer is prepared by a waterproof coating, which comprises the following materials: epoxy resin (E51, Aladdin Chemical Reagent Co., Ltd.), PDMS (polydimethylsiloxane), triethylenetetramine, curing agent (hexamethylenediamine), titanium dioxide (average particle size of 60nm), and solvent (ethyl acetate), with specific quantities shown in the table below.

[0061] On the other hand, this application provides a method for preparing ceramsite for metal sound barriers, comprising the following steps:

[0062] S1. Inner core preparation: Take fly ash, cement, quicklime, hydrated lime, expanded perlite, hydrogen peroxide and water, stir and granulate, and cure naturally for 28 days according to standard to obtain the inner core;

[0063] S2. Preparation of waterproof coating: Dissolve epoxy resin and PDMS in a solvent, add triethylenetetramine, curing agent and titanium dioxide, stir, and prepare waterproof coating;

[0064] S3. Preparation of ceramsite: Waterproof coating is sprayed on the outside of the inner core and dried to obtain ceramsite.

[0065] Table 1. Core composition of Examples 1-3

[0066]

[0067] Table 2 Composition of Waterproof Coatings in Examples 1-3

[0068]

[0069] Example 4

[0070] The difference from Example 2 is that the inner core also includes 3.5 kg of bio-cellulose charcoal.

[0071] Example 5

[0072] The difference from Example 2 is that the inner core also includes 3.5 parts of bio-cellulose char prepared in Preparation Example 1.

[0073] Example 6

[0074] The difference from Example 2 is that the modified titanium dioxide prepared in Example 2 of equal mass is used instead of the titanium dioxide in Example 2 to prepare the waterproof coating.

[0075] Example 7

[0076] The difference from Example 2 is that the waterproof coating also includes 1.5 kg of polyurethane.

[0077] Example 8

[0078] The difference from Example 2 is that the waterproof coating also includes 1.5 kg of the modified polyurethane prepared in Preparation Example 3.

[0079] Example 9

[0080] The difference from Example 2 is that after granulation, the product is cured by autoclaving at 130°C for 12 hours using a vertical autoclave.

[0081] Example 10

[0082] The difference from Example 2 is that in step S3, the inner core is mixed with water-sprayed ammonium acetate (ammonium acetate: water = 10:1), filtered, and dried to obtain a pretreated inner core. Then, a waterproof coating is sprayed on the outside of the pretreated inner core, heated to 90°C, and dried to obtain ceramsite.

[0083] Example 11

[0084] A method for preparing ceramsite:

[0085] Construction site waste soil, sludge, solid waste, and rice husks are mixed in a mass ratio of 100:20:10:5 and fermented at a temperature of 40-60℃ to obtain fermented soil. Before entering the kiln, the moisture content of the soil is controlled to be ≤20%, preferably 15-20%.

[0086] The steps for preparing ceramsite are as follows:

[0087] S1. Coarse crushing: Feeding (feeder, speed, output) - coarse crushing of soil (horizontal soil crusher (2-5 stages)) - coarse screening (5-10mm square hole screen);

[0088] S2, Fine crushing: Feeding (feeder, speed, output) - fine crushing of soil (vertical soil crusher 1-2 stages) - fine screening (drum screen 2-5mm square hole screen);

[0089] S3. Granulation: Rolling granulation (disc granulator, tilt angle 70° (40-80), rotation speed 10r / min (5-30));

[0090] S4. Firing:

[0091] (1) Feeding: The ratio of different sizes of raw ceramsite: large particle size 15-20mm: small particle size 2-5mm is about 5-30%. Feeding amount per hour: 500 cubic meters / day.

[0092] (2) Firing: (Rotary kiln: kiln opening size 1.6m-2m gradually decreases, kiln length 70m, inclination angle 3.5°, rotation speed 3.5-4.5r / min; rice husk 30t / 24h).

[0093] (3) Temperature control:

[0094] Preheating temperature: 200-400℃;

[0095] Firing temperature: 400-800℃;

[0096] Firing temperature: 1100-1150℃;

[0097] Air volume 6000-10000 m³ 3 / min;

[0098] The total firing time is approximately 50-60 minutes.

[0099] (4) Discharge

[0100] 5. Cooling: (natural cooling, water cooling, air cooling, energy recovery)

[0101] 6. Screening: Coarse screen (20mm square hole screen) - gradient drum screen (5mm-10mm) - fine screen (gyratory screen 4.75mm-3.6mm-2.36mm).

[0102] The performance of the expanded clay aggregate was tested and found to be as follows:

[0103] 1. Bulk density: 520-580 kg / m³ 3 ;

[0104] 2. Particle size: 0.6-2.36mm;

[0105] 3. Cylinder compressive strength: ≥2MPa.

[0106] Comparative Example

[0107] Comparative Example 1

[0108] The difference between this comparative example and Example 2 is that no expanded perlite was added in this comparative example, and there was no waterproof coating.

[0109] Performance testing

[0110] (1) Sound absorption performance test: The standing wave tube method was used to test according to the "Standard for Measurement of Sound Absorption Coefficient and Acoustic Impedance of Standing Wave Tube Method" (GBJ88-85). The sample was made into a 96mm×100mm ceramsite concrete cylinder with a fixed mix ratio. The sound frequency range was taken as the actual value of the rail transit environment (200-2000Hz).

[0111] (2) Mechanical strength test: The test shall be conducted in accordance with the relevant provisions of GB17431.2-2010 "Lightweight aggregates and their test methods Part 2: Lightweight aggregates test methods";

[0112] (3) Scratch resistance test: According to the national standard GB1768-(79)88 Test method for paint film abrasion resistance, the JM-1 type paint film abrasion tester is used. After a certain number of abrasion cycles, the weight loss of the paint film is used to represent its abrasion resistance.

[0113] Table 3 Performance Testing

[0114]

[0115] By comparing the performance test results in Table 3, we can find that:

[0116] 1. A comparison of Examples 1-3 and Comparative Example 1 reveals that the sound absorption, strength, and water resistance of the ceramsite prepared in Examples 1-3 are all improved. This indicates that the addition of expanded perlite to the ceramsite in this application, acting as a pore-forming agent, introduces a large number of closed pores into the ceramsite. Furthermore, pores are formed between the expanded perlite and the main ceramsite material, increasing the porosity within the ceramsite and thus achieving better sound absorption and noise reduction. Simultaneously, the optimized amount of expanded perlite ensures that calcium hydroxide is less likely to be reduced to hydrated calcium carbonate, thereby reducing the possibility of calcium silicate hydrate clogging the pores.

[0117] 2. A comparison between Examples 4-5 and Example 2 reveals that the sound absorption effect and strength of the ceramsite prepared in Examples 4-5 are improved. This indicates that the addition of fibrous carbon to the core in this application, which contains a large number of microporous structures, allows for the formation of a graded pore structure within the ceramsite. This enables the ceramsite to absorb and shield noise across multiple wavelengths, effectively improving the sound absorption and noise reduction effect of the metal sound barrier.

[0118] 3. A comparison between Examples 6-8 and Example 2 reveals that the sound absorption and water resistance of the ceramsite prepared in Examples 6-8 are improved. This indicates that modifying titanium dioxide with a titanate coupling agent in this application improves the surface energy of titanium dioxide, allowing it to be uniformly dispersed in the waterproof coating, thereby achieving a uniform waterproof and self-cleaning effect on the surface of the ceramsite. Adding polyurethane to the waterproof coating, which possesses excellent damping properties, imparts a damping and noise reduction effect to the ceramsite. Furthermore, modifying the polyurethane with epoxy resin allows the epoxy resin to form an interpenetrating network structure with the polyurethane, further enhancing the damping and noise reduction function of the polyurethane and improving the bonding effect between the waterproof coating and the core, resulting in stable and excellent waterproof performance for the ceramsite.

[0119] 4. A comparison between Example 9 and Example 2 reveals that the strength of the ceramsite prepared in Example 9 is improved. This indicates that the autoclaving treatment of ceramsite in this application can promote the hydration reaction inside the ceramsite, producing hydration products such as tobermorite and CSH gel with high crystallinity, making the ceramsite more compact, ensuring the strength of the ceramsite, and facilitating the control of the pore size inside the ceramsite.

[0120] 5. A comparison between Example 10 and Example 2 reveals that the sound absorption effect of the ceramsite prepared in Example 10 is improved. This indicates that in this application, the core is pre-mixed with ammonium acetate, and the ammonium acetate fills the surface pores of the core, reducing the possibility of the waterproof coating filling the surface pores of the core. After spraying the waterproof coating, the ceramsite is heated and decomposed to produce gas. This gas not only impacts the blocked pores inside the ceramsite but also blows away the waterproof coating adhering to the surface pores of the core, thus maintaining a better number of pores on the surface of the ceramsite, i.e., maintaining the sound absorption effect of the ceramsite.

[0121] 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 type of ceramic aggregate for metal sound barriers, characterized in that, Includes an inner core and a waterproof layer, wherein the inner core comprises the following materials in parts by weight: 100 parts fly ash; 20 parts cement; 8 parts of calcined gypsum; 4 parts quicklime; 6-8 parts expanded perlite; 2.5-7.5 parts hydrogen peroxide; 2 parts rice bran; The waterproof layer is prepared by a waterproof coating, which comprises the following materials in parts by weight: 5 parts epoxy resin; Two copies of PDMS; 1.7 parts of triethylenetetramine; 0.3 parts curing agent; 0.3-0.5 parts of titanium dioxide; 35 parts solvent.

2. The ceramic aggregate for a metal sound barrier according to claim 1, characterized in that: The inner core also includes 3-4 parts by weight of carbon fiber.

3. The ceramic aggregate for a metal sound barrier according to claim 2, characterized in that: The fiber charcoal is prepared as follows: waste bio-fiber charcoal is crushed, placed in a tube furnace for pyrolysis, and ground to obtain fiber charcoal.

4. The ceramic aggregate for a metal sound barrier according to claim 3, characterized in that: The titanium dioxide is titanium dioxide modified with a titanate coupling agent.

5. The ceramic aggregate for a metal sound barrier according to claim 4, characterized in that: The waterproof coating also includes 1-2 parts of polyurethane.

6. The ceramic aggregate for a metal sound barrier according to claim 5, characterized in that: The polyurethane is epoxy resin modified polyurethane.

7. The ceramic aggregate for a metal sound barrier according to claim 1, characterized in that: The epoxy resin modified polyurethane is prepared as follows: polyether polyol is dehydrated, TDI is added, and the mixture is stirred to react, resulting in a polyurethane prepolymer; epoxy resin is heated to reduce its viscosity, a catalyst and the polyurethane prepolymer are added, and the mixture is defoamed under vacuum to obtain epoxy resin modified polyurethane.

8. A method for preparing ceramsite for metal sound barriers according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Inner core preparation: Take fly ash, cement, quicklime, slaked lime, expanded perlite, rice husk, hydrogen peroxide and water, stir and granulate, cure to obtain the inner core; S2. Preparation of waterproof coating: Dissolve epoxy resin and PDMS in a solvent, add triethylenetetramine, curing agent and titanium dioxide, stir, and prepare waterproof coating; S3. Preparation of ceramsite: Waterproof coating is sprayed on the outside of the inner core and dried to obtain ceramsite.

9. A method for preparing ceramsite for metal sound barriers according to claim 8, characterized in that: The curing process in step S1 is autoclaving.

10. A method for preparing ceramsite for metal sound barriers according to claim 8, characterized in that: In step S3, the inner core is pre-mixed with ammonium acetate sprayed with water, filtered, and dried to obtain a pre-treated inner core. Then, a waterproof coating is sprayed on the outside of the pre-treated inner core, heated, and dried to obtain ceramsite.

Images