High-strength light-weight heat-insulation cement-based composite material and preparation method thereof

Abstract

The invention discloses a high-strength light-weight heat-insulation cement-based composite material and a preparation method thereof, and belongs to the technical field of building materials. The composite material comprises the following components in parts by volume: 12-21 parts of Portland cement, 1.5-2.5 parts of aluminate cement, 4-7 parts of silica fume, 30-60 parts of expandable polystyrene particles, 10-15 parts of glass bead particles, 0-1.5 parts of organic fibers, 15-25 parts of water and 0.3-0.4 part of a water reducing agent. The preparation method comprises the following steps: mixing dry materials, adding water and a water reducing agent, stirring, adding polystyrene particles in batches, adding organic fibers, uniformly mixing, carrying out hot press molding, and carrying out high-temperature maintenance. The apparent density of the obtained material is 600-1200 kg / m < 3 >, the compressive strength is not lower than 18 MPa, the heat conductivity coefficient is not higher than 0.3 W / (m.K), the weighted sound absorption coefficient reaches 0.7, and the material has light weight, high strength, heat insulation and good acoustic performance and is suitable for the fields of buildings, bridges, ocean engineering and the like.

Description

Technical Field

[0001] This invention relates to a high-strength, lightweight, heat-insulating cement-based composite material and its preparation method, belonging to the field of building materials technology. Background Technology

[0002] Cement-based composite materials are the most widely used man-made building materials. With the acceleration of industrialization and urbanization, and the continuous upgrading of consumption patterns, my country's energy demand is experiencing rigid growth, and resource and environmental issues remain one of the bottlenecks restricting my country's economic and social development. Weight reduction technologies, addressing the heavy weight of concrete, are an effective measure to conserve resources and promote green and low-carbon development.

[0003] Lightweight and high-strength concrete is an important development direction for concrete materials. Based on the composition of cement-based materials, lightweighting measures mainly include introducing air bubbles, using lightweight aggregates, and filling with lightweight materials such as foam. However, aerated concrete and foamed concrete have a loose and porous structure, often exhibiting disadvantages such as low strength, poor toughness, and susceptibility to cracking, limiting their applications to the enclosure structures of civil buildings. Chinese patent application CN114349429A discloses a lightweight concrete with excellent compressive strength, flexural strength, and low water absorption, but lacks good thermal insulation properties. Therefore, there is an urgent need to achieve high-strength, lightweight, and functionally synergistic effects in cement-based composite materials.

[0004] Expandable polystyrene granules are polystyrene products with added foaming agents. They have the characteristics of high compressive strength, low apparent density, low thermal conductivity, and good cushioning and shock absorption. Adding foaming agents can reduce the density of the material and improve its thermal insulation and sound absorption performance.

[0005] Glass microspheres are hollow structures made of sodium-calcium borosilicate glass. They have advantages such as high strength, low density, and good chemical stability, making them very suitable for improving the mechanical strength and insulation properties of lightweight materials.

[0006] Silica fume is an ultrafine siliceous powder material with a specific surface area greater than 10,000 m². 2 / kg, when added, can adjust the microporous structure of cement-based materials, ensuring the early strength of the materials.

[0007] Polyvinyl alcohol fiber is a synthetic organic fiber with a tensile strength of up to 1200 MPa and an elastic modulus greater than 30 GPa. It has excellent ductility and heat resistance. Adding it can improve the toughness of the material and reduce the risk of cracking. Summary of the Invention

[0008] In view of the technical problems existing in the background art, the present invention provides a high-strength lightweight thermal insulation cement-based composite material and its preparation method, aiming to obtain a high-strength lightweight thermal insulation cement-based composite material with low self-weight, high compressive strength, good flexural toughness and good thermal insulation performance.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0010] A method for preparing a high-strength, lightweight, thermally insulating cement-based composite material includes the following steps:

[0011] S1. Weigh 12-21 parts of silicate cement, 1.5-2.5 parts of aluminate cement, and 4-7 parts of silica fume by volume, and dry mix them evenly to obtain the first dry mixture.

[0012] S2. Add 10-15 parts of glass microspheres to the first mixed dry material by volume ratio, and dry mix and stir evenly to obtain the second mixed dry material.

[0013] S3. Weigh 15-25 parts of water and 0.3-0.4 parts of water-reducing agent by volume, mix them evenly, and add them to the second dry mixture. Stir at 200-300 r / min for 3-5 min, and add 30-60 parts of expandable polystyrene particles in batches during the stirring process to obtain a semi-dry powder material.

[0014] S4. Add 0-1.5 parts of organic fiber to the semi-dry powder material by volume ratio, and stir at 300 r / min for 1-2 min to obtain a semi-dry composite material slurry.

[0015] S5. Place the slurry in a mold and hot-press it at 60°C and 15 MPa for 20-25 minutes, then demold to obtain the blank.

[0016] S6. Curing the green body at 60-80℃ and 90%-95% relative humidity for 48-60 hours, followed by curing at 20±2℃ and 90%-95% relative humidity.

[0017] Preferably, in step S1, the silicate cement has a strength grade of not less than 42.5; the aluminate cement has a calcium aluminate content of ≥65% and a strength grade of not less than 42.5; the silica fume has a SiO2 content of ≥65% and a specific surface area of ​​≥10000 m². 2 / kg.

[0018] Preferably, in steps S2 and S3, the expandable polystyrene particles have a particle size of 0.5–0.8 mm and a bulk density ≤35 kg / m³. 3The glass microspheres have a particle size of 1–100 μm and a bulk density of ≤480 kg / m³. 3 .

[0019] Preferably, in step S4, the organic fiber is polyvinyl alcohol fiber, with a single filament diameter of 0.02-0.04 mm, a length of 10-15 mm, a tensile strength ≥1200 MPa, and an elastic modulus ≥30 GPa.

[0020] Preferably, in step S3, the water-reducing agent is a polycarboxylate-based water-reducing agent powder with a water reduction rate of 30-35%.

[0021] The present invention also provides a high-strength, lightweight, heat-insulating cement-based composite material, which is prepared by the above-described method.

[0022] Preferred: its apparent density is 600–1200 kg / m³ 3 The compressive strength is not less than 18 MPa, the thermal conductivity is not higher than 0.3 W / (m·K), and the weighted sound absorption coefficient reaches 0.7.

[0023] Preferred: its flexural strength is 6.5 to 13.3 MPa.

[0024] The present invention also provides a building material made of the aforementioned high-strength, lightweight, heat-insulating cement-based composite material.

[0025] The advantages of this application, which differ from existing technologies, include:

[0026] The high-strength, lightweight, thermally insulating cement-based composite material provided by this invention features a simple manufacturing process, high early strength, and the ability to achieve integrated structural and functional requirements for lightweight cement-based materials. It is highly suitable for applications in bridges, buildings, and marine engineering, offering a new approach to the functionality of cement-based materials. Specifically, this invention includes the following advantages:

[0027] 1. By combining a composite cementitious system (silicate cement / aluminate cement / silica fume) with dual lightweight functional particles (expandable polystyrene particles and glass microsphere particles) in a specific volume ratio, the industry problem of low strength and difficulty in balancing thermal insulation and load-bearing capacity of lightweight materials is fundamentally solved.

[0028] 2. The material should be maintained at 600–1200 kg / m³. 3 While maintaining low density, it achieves a high compressive strength of ≥18 MPa, a low thermal conductivity of ≤0.3 W / (m·K) and a high weighted sound absorption coefficient of ≥0.7, and possesses excellent flexural toughness. Its comprehensive performance far exceeds that of traditional lightweight cement-based materials.

[0029] 3. The mixing sequence of dry mixing, liquid addition and stirring, batch addition of lightweight particles, hot pressing molding, and high temperature and high humidity curing system ensures uniform dispersion of components, dense structure and rapid early strength development, strong process controllability and stable product performance.

[0030] 4. This material combines structural performance with thermal insulation and soundproofing functions, successfully breaking through the traditional limitation that lightweight cement materials are only suitable for non-load-bearing enclosure structures. It can be widely used in fields with higher performance requirements, such as construction, bridges, and marine engineering. Detailed Implementation

[0031] The present invention is further described below through embodiments, but the present invention is not limited to these embodiments.

[0032] In the following specific implementation plan, all materials are silicate cement, aluminate cement, silica fume, expandable polystyrene granules, glass microspheres, organic fibers, water, and water-reducing agent. The expandable polystyrene granules and glass microspheres were purchased from 3M Technology Corporation, the organic fibers from Kuraray (Shanghai) Co., Ltd., and the water-reducing agent from Jiangsu Subote Co., Ltd.

[0033] Example 1:

[0034] In this embodiment, the high-strength lightweight thermal insulation cement-based composite material comprises the following components by volume ratio: silicate cement: aluminate cement: silica fume: expandable polystyrene particles: glass microsphere particles: organic fiber: water: water-reducing agent = 21: 2.5: 7: 30: 15: 0.75: 25: 0.3.

[0035] in:

[0036] The silicate cement is P•Ⅰ 42.5 type reference cement, and the aluminate cement is CA-50 type.

[0037] The expandable polystyrene particles have a particle size of 0.8 mm and an apparent density of 30 kg / m³. 3 .

[0038] The glass microspheres have a median particle size of 43 μm and an apparent density of 450 kg / m³. 3 Its compressive strength is 41 MPa.

[0039] The organic fiber is polyvinyl alcohol fiber with a tensile strength of 1200 MPa, a length of 12 mm, and a single filament diameter of 40 µm.

[0040] The water-reducing agent is a polycarboxylate water-reducing agent, in powder form, with a water reduction rate of 30%.

[0041] The preparation method of the high-strength lightweight thermal insulation cement-based composite material in this embodiment includes the following steps:

[0042] S1. Weigh out silicate cement, aluminate cement and silica fume according to the proportion, dry mix them evenly to obtain a mixed dry material;

[0043] S2. Weigh the glass microspheres according to the proportion, dry mix and stir evenly to obtain the mixed dry material;

[0044] S3. Weigh out water and water-reducing agent according to the ratio, mix them evenly and add them to the mixed dry material. Stir at a speed of 200-300 r / min for 3-5 minutes. During this period, sprinkle in expandable polystyrene particles in batches. After uniform mixing, a semi-dry powder material is obtained.

[0045] S4. Weigh the organic fibers according to the ratio, add the organic fibers at a speed of 300 r / min and stir for 1 to 2 minutes until uniform to obtain a semi-dry high-strength lightweight thermal insulation cement-based composite material.

[0046] S5. Place the semi-dry high-strength lightweight thermal insulation cement-based composite material in a mold and hot-press it for 25 minutes at 60℃ and 15 MPa. After demolding, the high-strength lightweight thermal insulation cement-based composite material is obtained.

[0047] S6. Place under high temperature curing conditions of 60-80℃ and relative humidity of 90-95% RH for 48-60 hours. After that, it can be cured under standard curing conditions of 20±2℃ and relative humidity of 90-95% RH.

[0048] It can be used for testing and application after one week of curing. The measured performance is as follows: density is 1160 kg / m³. 3 It has a compressive strength of 48 MPa, a flexural strength of 6.5 MPa, a thermal conductivity of 0.27 W / (m·K), and a sound absorption coefficient of 0.39 at 5000 Hz.

[0049] Example 2:

[0050] In this embodiment, the high-strength lightweight thermal insulation cement-based composite material comprises the following components by volume ratio: silicate cement: aluminate cement: silica fume: expandable polystyrene particles: glass microsphere particles: organic fiber: water: water-reducing agent = 18: 2: 6: 40: 13: 0.75: 20: 0.3.

[0051] in:

[0052] The silicate cement is P•Ⅰ 42.5 type reference cement, and the aluminate cement is CA-50 type.

[0053] The expandable polystyrene particles have a particle size of 0.8 mm and an apparent density of 30 kg / m³. 3 .

[0054] The glass microspheres have a median particle size of 43 μm and an apparent density of 450 kg / m³. 3 Its compressive strength is 41 MPa.

[0055] The organic fiber is polyvinyl alcohol fiber with a tensile strength of 1200 MPa, a length of 12 mm, and a single filament diameter of 40 µm.

[0056] The water-reducing agent is a polycarboxylate water-reducing agent, in powder form, with a water reduction rate of 30%.

[0057] The preparation method of the high-strength lightweight thermal insulation cement-based composite material in this embodiment includes the following steps:

[0058] S1. Weigh out silicate cement, aluminate cement and silica fume according to the proportion, dry mix them evenly to obtain a mixed dry material;

[0059] S2. Weigh the glass microspheres according to the proportion, dry mix and stir evenly to obtain the mixed dry material;

[0060] S3. Weigh out water and water-reducing agent according to the ratio, mix them evenly and add them to the mixed dry material. Stir at a speed of 200-300 r / min for 3-5 minutes. During this period, sprinkle in expandable polystyrene particles in batches. After uniform mixing, a semi-dry powder material is obtained.

[0061] S4. Weigh the organic fibers according to the ratio, add the organic fibers at a speed of 300 r / min and stir for 1 to 2 minutes until uniform to obtain a semi-dry high-strength lightweight thermal insulation cement-based composite material.

[0062] S5. Place the semi-dry high-strength lightweight thermal insulation cement-based composite material in a mold and hot-press it for 20 minutes at 60℃ and 15 MPa. After demolding, the high-strength lightweight thermal insulation cement-based composite material is obtained.

[0063] S6. Place under high temperature curing conditions of 60℃ and relative humidity of 90~95% RH for 48 hours, and then cure under standard curing conditions of 20±2℃ and relative humidity of 90~95% RH.

[0064] It can be used for testing and application after one week of curing. The measured performance is as follows: density is 950 kg / m³. 3 It has a compressive strength of 38 MPa, a flexural strength of 8.2 MPa, a thermal conductivity of 0.23 W / (m·K), and a sound absorption coefficient of 0.52 at 5000 Hz.

[0065] Example 3:

[0066] In this embodiment, the high-strength lightweight thermal insulation cement-based composite material comprises the following components by volume ratio: silicate cement: aluminate cement: silica fume: expandable polystyrene particles: glass microsphere particles: organic fiber: water: water-reducing agent = 15: 1.5: 5: 50: 12: 1.5: 18: 0.4.

[0067] in:

[0068] The silicate cement is P•Ⅰ 42.5 type reference cement, and the aluminate cement is CA-50 type.

[0069] The expandable polystyrene particles have a particle size of 0.5 mm and an apparent density of 35 kg / m³. 3 .

[0070] The glass microspheres have a median particle size of 43 μm and an apparent density of 450 kg / m³. 3 Its compressive strength is 41 MPa.

[0071] The organic fiber is polyvinyl alcohol fiber, with a tensile strength exceeding 1600 MPa, a length of 12 mm, and a single filament diameter of 38 µm.

[0072] The water-reducing agent is a polycarboxylate water-reducing agent, in powder form, with a water reduction rate of 30%.

[0073] The preparation method of the high-strength lightweight thermal insulation cement-based composite material in this embodiment includes the following steps:

[0074] S1. Weigh out silicate cement, aluminate cement and silica fume according to the proportion, dry mix them evenly to obtain a mixed dry material;

[0075] S2. Weigh the glass microspheres according to the proportion, dry mix and stir evenly to obtain the mixed dry material;

[0076] S3. Weigh out water and water-reducing agent according to the ratio, mix them evenly and add them to the mixed dry material. Stir at a speed of 200-300 r / min for 3-5 minutes. During this period, sprinkle in expandable polystyrene particles in batches. After uniform mixing, a semi-dry powder material is obtained.

[0077] S4. Weigh the organic fibers according to the ratio, add the organic fibers at a speed of 300 r / min and stir for 1 to 2 minutes until uniform to obtain a semi-dry high-strength lightweight thermal insulation cement-based composite material.

[0078] S5. Place the semi-dry high-strength lightweight thermal insulation cement-based composite material in a mold and hot-press it for 20 minutes at 60℃ and 15 MPa. After demolding, the high-strength lightweight thermal insulation cement-based composite material is obtained.

[0079] S6. Place under high temperature curing conditions of 80℃ and relative humidity of 90~95% RH for 60 hours, and then cure under standard curing conditions of 20±2℃ and relative humidity of 90~95% RH.

[0080] It can be used for testing and application after one week of curing. The measured performance is as follows: density is 760 kg / m³. 3 It has a compressive strength of 35 MPa, a flexural strength of 13.3 MPa, a thermal conductivity of 0.19 W / (m·K), and a sound absorption coefficient of 0.68 at 5000 Hz.

[0081] Example 4:

[0082] In this embodiment, the high-strength lightweight thermal insulation cement-based composite material comprises the following components by volume ratio: silicate cement: aluminate cement: silica fume: expandable polystyrene particles: glass microsphere particles: organic fiber: water: water-reducing agent = 12: 1.5: 4: 60: 10: 1.5: 15: 0.4.

[0083] in:

[0084] The silicate cement is P•Ⅰ 52.5 type reference cement, and the aluminate cement is CA-50 type.

[0085] The expandable polystyrene particles have a particle size of 0.6 mm and an apparent density of 35 kg / m³. 3 .

[0086] The glass microspheres have a median particle size of 38 μm and an apparent density of 450 kg / m³. 3 Its compressive strength is 45 MPa.

[0087] The organic fiber is polyvinyl alcohol fiber, with a tensile strength exceeding 1600 MPa, a length of 12 mm, and a single filament diameter of 38 µm.

[0088] The water-reducing agent is a polycarboxylate water-reducing agent, in powder form, with a water reduction rate of 30%.

[0089] The preparation method of the high-strength lightweight thermal insulation cement-based composite material in this embodiment includes the following steps:

[0090] S1. Weigh out silicate cement, aluminate cement and silica fume according to the proportion, dry mix them evenly to obtain a mixed dry material;

[0091] S2. Weigh the glass microspheres according to the proportion, dry mix and stir evenly to obtain the mixed dry material;

[0092] S3. Weigh out water and water-reducing agent according to the ratio, mix them evenly and add them to the mixed dry material. Stir at a speed of 200-300 r / min for 3-5 minutes. During this period, sprinkle in expandable polystyrene particles in batches. After uniform mixing, a semi-dry powder material is obtained.

[0093] S4. Weigh the organic fibers according to the ratio, add the organic fibers at a speed of 300 r / min and stir for 1 to 2 minutes until uniform to obtain a semi-dry high-strength lightweight thermal insulation cement-based composite material.

[0094] S5. Place the semi-dry high-strength lightweight thermal insulation cement-based composite material in a mold and hot-press it for 25 minutes at 60℃ and 15 MPa. After demolding, the high-strength lightweight thermal insulation cement-based composite material is obtained.

[0095] S6. Place under high-temperature curing conditions of 60℃ and relative humidity of 90~95% RH for 60 hours, and then cure under standard curing conditions of 20±2℃ and relative humidity of 90~95% RH.

[0096] It can be used for testing and application after one week of curing. The measured performance is as follows: density is 620 kg / m³. 3 It has a compressive strength of 21 MPa, a flexural strength of 7.1 MPa, a thermal conductivity of 0.15 W / (m·K), and a sound absorption coefficient of 0.72 at 5000 Hz.

[0097] Example 5

[0098] The high-strength, lightweight, heat-insulating cement-based composite material preform obtained from any one of Examples 1 to 4 can be cut and surface-processed according to the design dimensions to obtain the desired building panels or components. These panels or components inherit the lightweight, high-strength, heat-insulating, and sound-insulating properties of the composite material.

[0099] In summary, this invention provides a stable, high-strength, lightweight, heat-insulating cement-based composite material and its preparation method. This invention can provide a reference for improving the structural and functional integration of lightweight cement-based materials. At the same time, this invention also broadens the application fields of lightweight cement-based composite materials.

Claims

1. A method for preparing a high-strength, lightweight, heat-insulating cement-based composite material, characterized in that, Includes the following steps: S1. Weigh 12-21 parts of silicate cement, 1.5-2.5 parts of aluminate cement, and 4-7 parts of silica fume by volume, and dry mix them evenly to obtain the first dry mixture. S2. Add 10-15 parts of glass microspheres to the first mixed dry material by volume ratio, and dry mix and stir evenly to obtain the second mixed dry material. S3. Weigh 15-25 parts of water and 0.3-0.4 parts of water-reducing agent by volume, mix them evenly, and add them to the second dry mixture. Stir at 200-300 r / min for 3-5 min, and add 30-60 parts of expandable polystyrene particles in batches during the stirring process to obtain a semi-dry powder material. S4. Add 0-1.5 parts of organic fiber to the semi-dry powder material by volume ratio, and stir at 300 r / min for 1-2 min to obtain a semi-dry composite material slurry. S5. Place the slurry in a mold and hot-press it at 60°C and 15 MPa for 20-25 minutes, then demold to obtain the blank. S6. Curing the green body at 60-80℃ and 90%-95% relative humidity for 48-60 hours, followed by curing at 20±2℃ and 90%-95% relative humidity.

2. The method according to claim 1, characterized in that: In step S1, the silicate cement has a strength grade of not less than 42.5; the aluminate cement has a calcium aluminate content of ≥65% and a strength grade of not less than 42.5; the silica fume has a SiO2 content of ≥65% and a specific surface area of ​​≥10000 m². 2 / kg.

3. The method according to claim 1, characterized in that: In steps S2 and S3, the expandable polystyrene particles have a particle size of 0.5–0.8 mm and a bulk density of ≤35 kg / m³. 3 The glass microspheres have a particle size of 1–100 μm and a bulk density of ≤480 kg / m³. 3 .

4. The method according to claim 1, characterized in that: In step S4, the organic fiber is polyvinyl alcohol fiber, with a single filament diameter of 0.02-0.04 mm, a length of 10-15 mm, a tensile strength ≥1200 MPa, and an elastic modulus ≥30 GPa.

5. The method according to claim 1, characterized in that: In step S3, the water-reducing agent is a polycarboxylate-based water-reducing agent powder with a water reduction rate of 30-35%.

6. A high-strength, lightweight, heat-insulating cement-based composite material, characterized in that, It is prepared by the method according to any one of claims 1 to 5.

7. The composite material according to claim 6, characterized in that: Its apparent density is 600–1200 kg / m³ 3 The compressive strength is not less than 18 MPa, the thermal conductivity is not higher than 0.3 W / (m·K), and the weighted sound absorption coefficient reaches 0.

7.

8. The composite material according to claim 6, characterized in that: Its flexural strength is 6.5–13.3 MPa.

9. A building material, characterized in that, It is made of any one of the high-strength, lightweight, heat-insulating cement-based composite materials according to claims 6 to 8.