A lightweight thermal insulation cement-based composite material and a method for preparing the same

Abstract

The application discloses a light heat-insulating cement-based composite material, and relates to the technical field of cement-based composite materials, which comprises the following components by weight: 40-60 parts of a cement matrix, 20-35 parts of light aggregate, 5-12 parts of a polymer modifier, and 0.5-0.3 parts of a functional additive; the cement matrix is sulphoaluminate cement or portland cement; the light aggregate comprises hollow glass microbeads with a particle size of 0.1-0.5 mm, expanded perlite with a particle size of 0.5-2 mm and surface-modified aerogel particles; the aerogel particles are silica aerogel or silicon carbide aerogel; the surface area of the aerogel particles is 700-600 m2 / g; the pore size of the aerogel particles is 40-50 nm; the polymer modifier is acrylate-styrene copolymer emulsion; the solid content of the acrylate-styrene copolymer emulsion is 50-45%; the glass transition temperature of the acrylate-styrene copolymer emulsion is -10-15 DEG C; and the functional additive comprises a cellulose ether thickening agent, a polycarboxylic acid water reducing agent and a nano-alumina dispersion liquid.

Description

Technical Field

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

[0002] Traditional cement-based materials, such as ordinary concrete and mortar, suffer from drawbacks such as high density, poor thermal insulation, and susceptibility to cracking, limiting their application in building energy conservation and lightweight structures. Taking building exterior walls as an example, the thermal conductivity of traditional concrete walls is generally higher than 1.5 W / (m·K), making it difficult to meet the modern building requirements for energy savings exceeding 75%. Furthermore, the material's heavy weight increases the structural load, limiting its application in high-rise buildings and large-span projects. In addition, traditional materials have insufficient crack resistance, easily developing cracks due to temperature stress or load, leading to insulation layer failure and reduced durability. However, existing lightweight insulating cement-based composite materials have relatively high thermal conductivity, further reducing the insulation effect of cement-based composite materials.

[0003] The existing defects of lightweight insulating cement-based composite materials are:

[0004] 1. Patent document CN107540334A discloses a magnesium oxychloride cement-based lightweight straw composite material and its preparation method, "comprising the following raw material components in the following mass ratio: 43-51 parts of lightly calcined magnesium powder, 10-15 parts of magnesium chloride, 40-44 parts of water, 0.40-0.53 parts of phosphoric acid, 0.5-1.85 parts of hydrogen peroxide, and straw fiber, wherein the bulk volume of straw fiber is 0.75-1.25 times the volume of cement paste; the magnesium oxide content of the lightly calcined magnesium powder is 95%, and the activity is 68%. The magnesium oxychloride cement-based lightweight straw composite material provided by this invention has the advantages of being green and environmentally friendly, and having thermal insulation properties." However, the existing lightweight thermal insulation cement-based composite materials have a high thermal conductivity, which reduces the thermal insulation effect of the cement-based composite materials.

[0005] 2. Patent document CN109293295A discloses a homogeneous composite material thermal insulation template and its production method, comprising the following components by weight: 600-700 kg of silicate cement; 7-10 kg of lightweight vacuum-foamed closed-cell thermal insulation particles; 12-16 kg of polymeric binder; 2-4 kg of cellulose hydroxypropyl methyl ether; 3-9 kg of high-plasticity film-forming agent; 2-4 kg of water-repellent agent; 2-4 kg of polypropylene fiber; 200-250 kg of lightweight calcium carbonate; and 200-250 kg of water. The above-mentioned homogeneous composite material thermal insulation template... By adding polypropylene fibers to homogeneous composite insulation templates, the crack resistance of homogeneous composite insulation templates can be improved; the addition of lightweight vacuum-foamed closed-cell insulation particles can improve the thermal insulation performance of homogeneous composite insulation templates; the addition of flame retardants and the use of inorganic materials to wrap uniformly distributed lightweight vacuum-foamed closed-cell insulation particles can improve the flame retardant and fireproof performance of homogeneous composite insulation templates, making the fireproof performance reach Class A; however, the compressive strength of existing lightweight thermal insulation cement-based composite materials is reduced, resulting in a decrease in the strength of cement-based composite materials.

[0006] 3. Patent document CN107351483A discloses a lightweight building panel, "comprising a composite material layer, an insulation layer bonded to the lower surface of the composite material layer, an aluminum plate bonded to the upper surface of the composite material layer, and a coating on the upper surface of the aluminum plate; the composite material layer comprises cement, paraffin wax, epoxy resin, glass fiber, methyl cellulose, sulfomethyl lignite, hydroxyethyl cellulose, and a foaming agent; the lower surface of the aluminum plate has multiple protrusions spaced along the length of the aluminum plate, and quick-setting cement is provided between the aluminum plate and the composite material layer, filling the gaps between adjacent protrusions; the coating comprises modified fluorinated polyurethane, epoxy resin, butanediol, isopropanol, polypropylene glycol, polyoxyethylene, potassium persulfate, aluminum tripolyphosphate, a stain-resistant agent, and a hydrophobic agent. It has good thermal insulation performance, a stable structure, high overall strength, good thermal insulation function, and good overall waterproof and stain-resistant properties." However, the existing lightweight thermal insulation cement-based composite material has a high bulk density, which reduces its compressive strength. Summary of the Invention

[0007] The purpose of this invention is to provide a lightweight thermally insulating cement-based composite material and its preparation method, so as to solve the technical problem mentioned in the background art that the existing lightweight thermally insulating cement-based composite materials have a high thermal conductivity, which reduces the thermal insulation effect of the cement-based composite materials.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a lightweight thermally insulating cement-based composite material, comprising the following material components by weight: 40-60 parts of cement matrix, 20-35 parts of lightweight aggregate, 5-12 parts of polymer modifier, and 0.5-0.3 parts of functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1-0.5 mm, expanded perlite with a particle size of 0.5-2 mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel, with a surface area of ​​700~600 m² / g and a pore size of 40~50 nm. The polymer modifier is an acrylate-styrene copolymer emulsion with a solid content of 50~45% and a glass transition temperature of -10℃~15℃. The functional additives include cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion.

[0009] Preferably, the hollow glass microspheres account for 10-25 parts by weight of the total lightweight aggregate, the expanded perlite accounts for 5-15 parts by weight of the total lightweight aggregate, and the surface-modified aerogel particles account for 3-8 parts by weight of the total lightweight aggregate.

[0010] Preferably, the mass ratio of hollow glass microspheres to expanded perlite is 1.5-2.5:1, and the aerogel particles are pretreated with silane coupling agent KH-570, resulting in a surface grafting rate of 85-95% for the aerogel particles after pretreatment.

[0011] Preferably, the aerogel particles have a core-shell structure, with the core being silica aerogel and the outer shell being a hydrophobically modified titanium dioxide coating with a thickness of 50-200 nm.

[0012] Preferably, in the core-shell structure of the aerogel particles, the titanium dioxide coating is subjected to in-situ ceramicization treatment to form a micron-sized protrusion structure with a protrusion height of 0.5-2μm and a density of 30-50 particles / μm², which is used to enhance the mechanical interlocking force with the cement matrix.

[0013] Preferably, the preparation method of the cement-based composite material includes the following steps:

[0014] Step S1, Lightweight aggregate pretreatment: Place the aerogel particles in a vacuum impregnation tank, inject 5-10% by weight of silane coupling agent ethanol solution, maintain at -0.1MPa for 30-60min, and dry at normal pressure for later use;

[0015] Step S2, Slurry mixing: Mix cement, 60% water, water-reducing agent and cellulose ether for 5-10 minutes to form cement-based slurry one;

[0016] Step S3, Gradual Incorporation: Hollow glass microspheres and expanded perlite are added sequentially to the cement-based slurry. After stirring at low speed for 3 minutes, aerogel particles and remaining water are added. The mixture is stirred at high speed for 5 minutes to form cement-based slurry II. The low-speed stirring is 200-400 rpm and the high-speed stirring is 800-1200 rpm.

[0017] Step S4: Inject acrylate-styrene copolymer emulsion into cement-based slurry II, and cure it by microwave radiation at 40-60℃ for 10-20 minutes with a microwave radiation power of 300-500W to form cement-based slurry III.

[0018] Step S5: After the cement-based slurry is injected into the mold, it is vibrated to compact it and then cured at a humidity of ≥95% and a temperature of 25±2℃.

[0019] Preferably, a three-dimensional steel fiber network is added to the cement matrix slurry. The three-dimensional steel fiber network accounts for 1.5-3% of the total material composition. The steel fiber length is 6-12mm, the steel fiber diameter is 0.2-0.5mm, the steel fiber is treated with zinc phosphate coating, and the steel fiber is embedded in the cement matrix in an X-shaped cross-weaving manner. The mesh spacing of the steel fiber is 10-15mm.

[0020] Preferably, the steel fiber network forms a gradient density distribution in the composite material: the fiber density in the 0-5mm region from the surface is 120-150 fibers / dm³, the fiber density in the 5-15mm region is 80-100 fibers / dm³, and the fiber density in the core region is ≤50 fibers / dm³.

[0021] Preferably, the microwave curing in step S4 uses gradient power control: 500W for the first 5 minutes, 300W for the next 5-15 minutes, and switches to 200W for the last 2 minutes before final curing.

[0022] Preferably, during the microwave curing process in step S4, a nitrogen protective gas flow is injected simultaneously, with a flow rate of 5-10 L / min, so that a Si3N4 passivation layer is formed on the aerogel surface.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. This invention comprises a material component consisting of the following parts by weight: 40 parts cement matrix, 20 parts lightweight aggregate, 5 parts polymer modifier, and 0.3 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1-0.5 mm, expanded perlite with a particle size of 0.5-2 mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel, with a surface area of ​​700-600 m² / g and a pore size of 40-50 mm. nm, the polymer modifier is acrylate-styrene copolymer emulsion, the solid content of acrylate-styrene copolymer emulsion is 50~45%, the glass transition temperature of acrylate-styrene copolymer emulsion is -10℃~15℃, the functional additives include cellulose ether thickener, polycarboxylate superplasticizer, nano alumina dispersion, hollow glass microspheres account for 10 parts by weight of the total lightweight aggregate, expanded perlite accounts for 5 parts by weight of the total lightweight aggregate, and surface modified aerogel particles account for 3 parts by weight of the total lightweight aggregate, thus realizing the function of improving the thermal insulation effect of cement-based composite materials;

[0025] 2. This invention utilizes aerogel particles with a mass ratio of hollow glass microspheres to expanded perlite of 1.5-2.5:1. The aerogel particles are pretreated with silane coupling agent KH-570, resulting in a surface grafting rate of 85-95%. The aerogel particles have a core-shell structure, with a silica aerogel core and a hydrophobically modified titanium dioxide coating on the outer shell. The titanium dioxide coating has a thickness of 50-200 nm. Within the core-shell structure of the aerogel particles, the titanium dioxide coating undergoes in-situ ceramicization to form micron-sized protrusions with a height of 0.5-2 μm and a density of 30-50 protrusions / μm². These protrusions enhance the mechanical bonding force with the cement matrix, thereby significantly improving the compressive strength and overall strength of the cement-based composite material.

[0026] 3. This invention utilizes a material composition comprising the following parts by weight: 40 parts cement matrix, 20 parts lightweight aggregate, 5 parts polymer modifier, and 0.3 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The mass ratio of hollow glass microspheres to expanded perlite is 1.5-2.5:1. The aerogel particles are pretreated with silane coupling agent KH-570, resulting in a surface grafting rate of 85-95%. The aerogel particles have a core-shell structure with a silica aerogel core. This invention achieves the function of reducing the bulk density and increasing the compressive strength of cement-based composite materials. Attached Figure Description

[0027] Figure 1 This is a schematic representation of the experimental data of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand this according to the specific circumstances.

[0031] Example 1, an embodiment of the present invention: a lightweight thermally insulating cement-based composite material, comprising the following material components by weight: 40 parts cement matrix, 20 parts lightweight aggregate, 5 parts polymer modifier, and 0.3 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel, with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is an acrylate-styrene copolymer emulsion with a solid content of 50~45% and a glass transition temperature of -10℃~15℃. The functional additive... The composition includes cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion. Hollow glass microspheres account for 10 parts by weight of the total lightweight aggregate, expanded perlite accounts for 5 parts by weight of the total lightweight aggregate, and surface-modified aerogel particles account for 3 parts by weight of the total lightweight aggregate. The mass ratio of hollow glass microspheres to expanded perlite is 1.5-2.5:1. The aerogel particles are pretreated with silane coupling agent KH-570, and the surface grafting rate of the aerogel particles after pretreatment is 85-95%. The aerogel particles have a core-shell structure, with a core of silica aerogel and a shell of hydrophobically modified titanium dioxide coating. The thickness of the titanium dioxide coating is 50-200 nm. In the core-shell structure of the aerogel particles, the titanium dioxide coating is subjected to in-situ ceramicization treatment to form a micron-level protrusion structure with a protrusion height of 0.5-2 μm and a density of 30-50 particles / μm², which is used to enhance the mechanical interlocking force with the cement matrix.

[0032] The preparation method of this cement-based composite material includes the following steps:

[0033] Step S1, Lightweight aggregate pretreatment: Place the aerogel particles in a vacuum impregnation tank, inject 5-10% by weight of silane coupling agent ethanol solution, maintain at -0.1MPa for 30-60min, and dry at normal pressure for later use;

[0034] Step S2, Slurry mixing: Mix cement, 60% water, water-reducing agent and cellulose ether for 5-10 minutes to form cement-based slurry one;

[0035] Step S3, Gradual Incorporation: Hollow glass microspheres and expanded perlite are added sequentially to the cement-based slurry. After stirring at low speed for 3 minutes, aerogel particles and remaining water are added. The mixture is stirred at high speed for 5 minutes to form cement-based slurry II. The low-speed stirring is 200-400 rpm and the high-speed stirring is 800-1200 rpm.

[0036] Step S4: Inject acrylate-styrene copolymer emulsion into cement-based slurry II, and cure it by microwave radiation at 40-60℃ for 10-20 minutes with a microwave radiation power of 300-500W to form cement-based slurry III.

[0037] Step S5: After the cement-based slurry is injected into the mold, it is vibrated to compact it and then cured at a humidity of ≥95% and a temperature of 25±2℃.

[0038] A three-dimensional steel fiber network is added to the cement-based slurry. The three-dimensional steel fiber network accounts for 1.5% of the total material composition. The steel fiber is 6 mm long and 0.2 mm in diameter. The steel fiber is treated with zinc phosphate coating. The steel fiber is embedded in the cement matrix in an X-shaped cross-weave pattern. The mesh spacing of the steel fiber is 10-15 mm. The steel fiber network forms a gradient density distribution in the composite material: the fiber density is 120-150 fibers / dm³ in the 0-5 mm area from the surface, 80-100 fibers / dm³ in the 5-15 mm area, and ≤50 fibers / dm³ in the core area. The microwave curing in step S4 adopts gradient power control: 500W for the first 5 minutes, 300W for the next 5-15 minutes, and switches to 200W for the last 2 minutes before final setting. During the microwave curing process in step S4, nitrogen protective gas flow is injected simultaneously at a flow rate of 5-10 L / min to generate a Si3N4 passivation layer on the aerogel surface.

[0039] Example 2, an embodiment of the present invention: a lightweight thermally insulating cement-based composite material, comprising the following material components by weight: 45 parts cement matrix, 25 parts lightweight aggregate, 7 parts polymer modifier, and 0.4 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel, with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is an acrylate-styrene copolymer emulsion with a solid content of 50~45% and a glass transition temperature of -10℃~15℃. The functional additive includes... The composition includes cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion. Hollow glass microspheres account for 15 parts by weight of the total lightweight aggregate, expanded perlite accounts for 10 parts by weight of the total lightweight aggregate, and surface-modified aerogel particles account for 4 parts by weight of the total lightweight aggregate. The mass ratio of hollow glass microspheres to expanded perlite is 1.5-2.5:1. The aerogel particles are pretreated with silane coupling agent KH-570, and the surface grafting rate of the aerogel particles after pretreatment is 85-95%. The aerogel particles have a core-shell structure, with a core of silica aerogel and a shell of hydrophobically modified titanium dioxide coating. The thickness of the titanium dioxide coating is 50-200 nm. In the core-shell structure of the aerogel particles, the titanium dioxide coating is subjected to in-situ ceramicization treatment to form a micron-level protrusion structure with a protrusion height of 0.5-2 μm and a density of 30-50 particles / μm², which is used to enhance the mechanical interlocking force with the cement matrix.

[0040] The preparation method of this cement-based composite material includes the following steps:

[0041] Step S1, Lightweight aggregate pretreatment: Place the aerogel particles in a vacuum impregnation tank, inject 5-10% by weight of silane coupling agent ethanol solution, maintain at -0.1MPa for 30-60min, and dry at normal pressure for later use;

[0042] Step S2, Slurry mixing: Mix cement, 60% water, water-reducing agent and cellulose ether for 5-10 minutes to form cement-based slurry one;

[0043] Step S3, Gradual Incorporation: Hollow glass microspheres and expanded perlite are added sequentially to the cement-based slurry. After stirring at low speed for 3 minutes, aerogel particles and remaining water are added. The mixture is stirred at high speed for 5 minutes to form cement-based slurry II. The low-speed stirring is 200-400 rpm and the high-speed stirring is 800-1200 rpm.

[0044] Step S4: Inject acrylate-styrene copolymer emulsion into cement-based slurry II, and cure it by microwave radiation at 40-60℃ for 10-20 minutes with a microwave radiation power of 300-500W to form cement-based slurry III.

[0045] Step S5: After the cement-based slurry is injected into the mold, it is vibrated to compact it and then cured at a humidity of ≥95% and a temperature of 25±2℃.

[0046] A three-dimensional steel fiber network is added to the cement-based slurry. The three-dimensional steel fiber network accounts for 2% of the total material composition. The steel fiber length is 6-12 mm and the steel fiber diameter is 0.2-0.5 mm. The steel fiber is treated with zinc phosphate coating. The steel fiber is embedded in the cement matrix in an X-shaped cross-weave pattern. The mesh spacing of the steel fiber is 10-15 mm. The steel fiber network forms a gradient density distribution in the composite material: the fiber density in the 0-5 mm area from the surface is 120-150 fibers / dm³, the density in the 5-15 mm area is 80-100 fibers / dm³, and the core area is ≤50 fibers / dm³. Microwave curing in step S4 adopts gradient power control: 500 W for the first 5 minutes, 300 W for the next 5-15 minutes, and switches to 200 W for the last 2 minutes before final setting. During the microwave curing process in step S4, nitrogen protective gas flow is injected simultaneously at a flow rate of 5-10 L / min to generate a Si3N4 passivation layer on the aerogel surface.

[0047] Example 3, an embodiment of the present invention: a lightweight thermally insulating cement-based composite material, comprising the following material components by weight: 50 parts cement matrix, 30 parts lightweight aggregate, 9 parts polymer modifier, and 0.3 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel, with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is an acrylate-styrene copolymer emulsion with a solid content of 50~45% and a glass transition temperature of -10℃~15℃. The functional additive includes... The composition includes cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion. Hollow glass microspheres account for 20 parts by weight of the total lightweight aggregate, expanded perlite accounts for 12 parts by weight of the total lightweight aggregate, and surface-modified aerogel particles account for 5 parts by weight of the total lightweight aggregate. The mass ratio of hollow glass microspheres to expanded perlite is 1.5-2.5:1. The aerogel particles are pretreated with silane coupling agent KH-570, and the surface grafting rate of the aerogel particles after pretreatment is 85-95%. The aerogel particles have a core-shell structure, with a core of silica aerogel and a shell of hydrophobically modified titanium dioxide coating. The thickness of the titanium dioxide coating is 50-200 nm. In the core-shell structure of the aerogel particles, the titanium dioxide coating is subjected to in-situ ceramicization treatment to form a micron-level protrusion structure with a protrusion height of 0.5-2 μm and a density of 30-50 particles / μm², which is used to enhance the mechanical interlocking force with the cement matrix.

[0048] The preparation method of this cement-based composite material includes the following steps:

[0049] Step S1, Lightweight aggregate pretreatment: Place the aerogel particles in a vacuum impregnation tank, inject 5-10% by weight of silane coupling agent ethanol solution, maintain at -0.1MPa for 30-60min, and dry at normal pressure for later use;

[0050] Step S2, Slurry mixing: Mix cement, 60% water, water-reducing agent and cellulose ether for 5-10 minutes to form cement-based slurry one;

[0051] Step S3, Gradual Incorporation: Hollow glass microspheres and expanded perlite are added sequentially to the cement-based slurry. After stirring at low speed for 3 minutes, aerogel particles and remaining water are added. The mixture is stirred at high speed for 5 minutes to form cement-based slurry II. The low-speed stirring is 200-400 rpm and the high-speed stirring is 800-1200 rpm.

[0052] Step S4: Inject acrylate-styrene copolymer emulsion into cement-based slurry II, and cure it by microwave radiation at 40-60℃ for 10-20 minutes with a microwave radiation power of 300-500W to form cement-based slurry III.

[0053] Step S5: After the cement-based slurry is injected into the mold, it is vibrated to compact it and then cured at a humidity of ≥95% and a temperature of 25±2℃.

[0054] A three-dimensional steel fiber network is added to the cement-based slurry. The three-dimensional steel fiber network accounts for 2% of the total material composition. The steel fiber length is 6-12 mm and the steel fiber diameter is 0.2-0.5 mm. The steel fiber is treated with zinc phosphate coating. The steel fiber is embedded in the cement matrix in an X-shaped cross-weave pattern. The mesh spacing of the steel fiber is 10-15 mm. The steel fiber network forms a gradient density distribution in the composite material: the fiber density in the 0-5 mm area from the surface is 120-150 fibers / dm³, the density in the 5-15 mm area is 80-100 fibers / dm³, and the core area is ≤50 fibers / dm³. Microwave curing in step S4 adopts gradient power control: 500 W for the first 5 minutes, 300 W for the next 5-15 minutes, and switches to 200 W for the last 2 minutes before final setting. During the microwave curing process in step S4, nitrogen protective gas flow is injected simultaneously at a flow rate of 5-10 L / min to generate a Si3N4 passivation layer on the aerogel surface.

[0055] Example 4, an embodiment of the present invention: a lightweight thermally insulating cement-based composite material, comprising the following material components by weight: 55 parts cement matrix, 30 parts lightweight aggregate, 10 parts polymer modifier, and 0.5 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel, with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is an acrylate-styrene copolymer emulsion with a solid content of 50~45% and a glass transition temperature of -10℃~15℃. The functional additive includes... The composition includes cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion. Hollow glass microspheres account for 22 parts by weight of the total lightweight aggregate, expanded perlite accounts for 13 parts by weight of the total lightweight aggregate, and surface-modified aerogel particles account for 7 parts by weight of the total lightweight aggregate. The mass ratio of hollow glass microspheres to expanded perlite is 1.5-2.5:1. The aerogel particles are pretreated with silane coupling agent KH-570, and the surface grafting rate of the aerogel particles after pretreatment is 85-95%. The aerogel particles have a core-shell structure, with a core of silica aerogel and a shell of hydrophobically modified titanium dioxide coating. The thickness of the titanium dioxide coating is 50-200 nm. In the core-shell structure of the aerogel particles, the titanium dioxide coating is subjected to in-situ ceramic treatment to form a micron-level protrusion structure with a protrusion height of 0.5-2 μm and a density of 30-50 particles / μm², which is used to enhance the mechanical interlocking force with the cement matrix.

[0056] The preparation method of this cement-based composite material includes the following steps:

[0057] Step S1, Lightweight aggregate pretreatment: Place the aerogel particles in a vacuum impregnation tank, inject 5-10% by weight of silane coupling agent ethanol solution, maintain at -0.1MPa for 30-60min, and dry at normal pressure for later use;

[0058] Step S2, Slurry mixing: Mix cement, 60% water, water-reducing agent and cellulose ether for 5-10 minutes to form cement-based slurry one;

[0059] Step S3, Gradual Incorporation: Hollow glass microspheres and expanded perlite are added sequentially to the cement-based slurry. After stirring at low speed for 3 minutes, aerogel particles and remaining water are added. The mixture is stirred at high speed for 5 minutes to form cement-based slurry II. The low-speed stirring is 200-400 rpm and the high-speed stirring is 800-1200 rpm.

[0060] Step S4: Inject acrylate-styrene copolymer emulsion into cement-based slurry II, and cure it by microwave radiation at 40-60℃ for 10-20 minutes with a microwave radiation power of 300-500W to form cement-based slurry III.

[0061] Step S5: After the cement-based slurry is injected into the mold, it is vibrated to compact it and then cured at a humidity of ≥95% and a temperature of 25±2℃.

[0062] A three-dimensional steel fiber network is added to the cement-based slurry. The three-dimensional steel fiber network accounts for 2.5% of the total material composition. The steel fiber length is 6-12 mm and the steel fiber diameter is 0.2-0.5 mm. The steel fiber is treated with zinc phosphate coating. The steel fiber is embedded in the cement matrix in an X-shaped cross-weave pattern. The mesh spacing of the steel fiber is 10-15 mm. The steel fiber network forms a gradient density distribution in the composite material: the fiber density in the 0-5 mm area from the surface is 120-150 fibers / dm³, the density in the 5-15 mm area is 80-100 fibers / dm³, and the core area is ≤50 fibers / dm³. Microwave curing in step S4 adopts gradient power control: 500 W for the first 5 minutes, 300 W for the next 5-15 minutes, and switches to 200 W for the last 2 minutes before final setting. During microwave curing in step S4, nitrogen protective gas flow is injected simultaneously at a flow rate of 5-10 L / min to generate a Si3N4 passivation layer on the aerogel surface.

[0063] Example 5, an embodiment of the present invention: a lightweight thermally insulating cement-based composite material, comprising the following material components by weight: 60 parts cement matrix, 35 parts lightweight aggregate, 12 parts polymer modifier, and 0.3 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel, with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is an acrylate-styrene copolymer emulsion with a solid content of 50~45% and a glass transition temperature of -10℃~15℃. The functional additive... The composition includes cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion. Hollow glass microspheres account for 25 parts by weight of the total lightweight aggregate, expanded perlite accounts for 15 parts by weight of the total lightweight aggregate, and surface-modified aerogel particles account for 8 parts by weight of the total lightweight aggregate. The mass ratio of hollow glass microspheres to expanded perlite is 1.5-2.5:1. The aerogel particles are pretreated with silane coupling agent KH-570, and the surface grafting rate of the aerogel particles after pretreatment is 85-95%. The aerogel particles have a core-shell structure, with a core of silica aerogel and a shell of hydrophobically modified titanium dioxide coating. The thickness of the titanium dioxide coating is 50-200 nm. In the core-shell structure of the aerogel particles, the titanium dioxide coating is subjected to in-situ ceramic treatment to form a micron-level protrusion structure with a protrusion height of 0.5-2 μm and a density of 30-50 particles / μm², which is used to enhance the mechanical interlocking force with the cement matrix.

[0064] The preparation method of this cement-based composite material includes the following steps:

[0065] Step S1, Lightweight aggregate pretreatment: Place the aerogel particles in a vacuum impregnation tank, inject 5-10% by weight of silane coupling agent ethanol solution, maintain at -0.1MPa for 30-60min, and dry at normal pressure for later use;

[0066] Step S2, Slurry mixing: Mix cement, 60% water, water-reducing agent and cellulose ether for 5-10 minutes to form cement-based slurry one;

[0067] Step S3, Gradual Incorporation: Hollow glass microspheres and expanded perlite are added sequentially to the cement-based slurry. After stirring at low speed for 3 minutes, aerogel particles and remaining water are added. The mixture is stirred at high speed for 5 minutes to form cement-based slurry II. The low-speed stirring is 200-400 rpm and the high-speed stirring is 800-1200 rpm.

[0068] Step S4: Inject acrylate-styrene copolymer emulsion into cement-based slurry II, and cure it by microwave radiation at 40-60℃ for 10-20 minutes with a microwave radiation power of 300-500W to form cement-based slurry III.

[0069] Step S5: After the cement-based slurry is injected into the mold, it is vibrated to compact it and then cured at a humidity of ≥95% and a temperature of 25±2℃.

[0070] A three-dimensional steel fiber network is added to the cement-based slurry. The three-dimensional steel fiber network accounts for 3% of the total material composition. The steel fiber length is 6-12 mm and the steel fiber diameter is 0.2-0.5 mm. The steel fiber is treated with zinc phosphate coating. The steel fiber is embedded in the cement matrix in an X-shaped cross-weave pattern. The mesh spacing of the steel fiber is 10-15 mm. The steel fiber network forms a gradient density distribution in the composite material: the fiber density in the 0-5 mm area from the surface is 120-150 fibers / dm³, the density in the 5-15 mm area is 80-100 fibers / dm³, and the core area is ≤50 fibers / dm³. The microwave curing in step S4 adopts gradient power control: 500W for the first 5 minutes, 300W for the next 5-15 minutes, and switches to 200W for the last 2 minutes before final setting. During the microwave curing process in step S4, nitrogen protective gas flow is injected simultaneously. The flow rate of the nitrogen protective gas flow is 5-10 L / min, so that a Si3N4 passivation layer is generated on the surface of the aerogel.

[0071] Comparative experiment:

[0072] The difference between Comparative Example 1 and Example 1 is that;

[0073] The material composition includes the following parts by weight: 40 parts cement matrix, 20 parts lightweight aggregate, 5 parts polymer modifier, and 0.3 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is acrylate- The styrene copolymer emulsion has a solid content of 50-45% and a glass transition temperature of -10℃ to 15℃. Functional additives include cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion. Hollow glass microspheres account for 10 parts by weight of the total lightweight aggregate, expanded perlite accounts for 5 parts by weight of the total lightweight aggregate, surface-modified aerogel particles account for 3 parts by weight of the total lightweight aggregate, and a three-dimensional steel fiber network accounts for 1.5% of the total material composition. The steel fiber length is 6mm and the steel fiber diameter is 0.2mm.

[0074] The difference between Comparative Example 1 and Example 2 is that;

[0075] The material composition includes the following parts by weight: 45 parts cement matrix, 25 parts lightweight aggregate, 7 parts polymer modifier, and 0.4 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is acrylate-styrene. The copolymer emulsion, specifically the acrylate-styrene copolymer emulsion, has a solid content of 50-45% and a glass transition temperature of -10℃ to 15℃. Functional additives include cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion. Hollow glass microspheres account for 15 parts by weight of the total lightweight aggregate, expanded perlite accounts for 10 parts by weight of the total lightweight aggregate, surface-modified aerogel particles account for 4 parts by weight of the total lightweight aggregate, and a three-dimensional steel fiber network accounts for 2% of the total material composition. The steel fiber length is 6-12 mm, and the steel fiber diameter is 0.2-0.5 mm.

[0076] The difference between Comparative Example 1 and Example 3 is that;

[0077] The material composition includes the following parts by weight: 50 parts cement matrix, 30 parts lightweight aggregate, 9 parts polymer modifier, and 0.3 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is acrylate-styrene. The copolymer emulsion, with a solid content of 50-45% for acrylate-styrene copolymer emulsion and a glass transition temperature of -10℃ to 15℃, includes functional additives such as cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion. Hollow glass microspheres account for 20 parts by weight of the total lightweight aggregate, expanded perlite accounts for 12 parts by weight of the total lightweight aggregate, surface-modified aerogel particles account for 5 parts by weight of the total lightweight aggregate, and a three-dimensional steel fiber network accounts for 2% of the total material composition. The steel fiber length is 6-12 mm and the steel fiber diameter is 0.2-0.5 mm.

[0078] The difference between Comparative Example 1 and Example 4 is that;

[0079] The material composition includes the following parts by weight: 55 parts cement matrix, 30 parts lightweight aggregate, 10 parts polymer modifier, and 0.5 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is an acrylate-styrene copolymer. The polyemulsion, specifically the acrylate-styrene copolymer emulsion, has a solid content of 50-45% and a glass transition temperature of -10℃ to 15℃. Functional additives include cellulose ether thickener, polycarboxylate superplasticizer, and nano-alumina dispersion. Hollow glass microspheres account for 22 parts by weight of the total lightweight aggregate, expanded perlite accounts for 13 parts by weight of the total lightweight aggregate, surface-modified aerogel particles account for 7 parts by weight of the total lightweight aggregate, and a three-dimensional steel fiber network accounts for 2.5% of the total material composition. The steel fiber length is 6-12 mm, and the steel fiber diameter is 0.2-0.5 mm.

[0080] The difference between Comparative Example 1 and Example 5 is that;

[0081] The material composition includes the following parts by weight: 60 parts cement matrix, 35 parts lightweight aggregate, 12 parts polymer modifier, and 0.3 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1~0.5mm, expanded perlite with a particle size of 0.5~2mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel with a surface area of ​​700~600m² / g and a pore size of 40~50nm. The polymer modifier is an acrylate-styrene copolymer emulsion. The solid content of the styrene copolymer emulsion is 50-45%, the glass transition temperature of the acrylate-styrene copolymer emulsion is -10℃ to 15℃, the functional additives include cellulose ether thickener, polycarboxylate superplasticizer, nano alumina dispersion, hollow glass microspheres account for 25 parts by weight of the total lightweight aggregate, expanded perlite accounts for 15 parts by weight of the total lightweight aggregate, surface modified aerogel particles account for 8 parts by weight of the total lightweight aggregate, and a three-dimensional steel fiber network is added to the cementitious slurry, the three-dimensional steel fiber network accounts for 3% of the total material components, the steel fiber length is 6-12mm, and the steel fiber diameter is 0.2-0.5mm.

[0082] The cement-based composite materials of Examples 1, 2, 3, 4, and 5 of the present invention were compared with the traditional cement-based composite material (Comparative Example 1) by conducting thermal conductivity, compressive strength, and bulk density experiments, and their values ​​were calculated and statistically analyzed. The results are shown in the table.

[0083]

[0084] The data in the table show that the thermal conductivity of the cement-based composite materials used in Examples 1, 2, 3, 4, and 5 of this invention is 0.045, 0.052, 0.042, 0.043, and 0.048, respectively, which is significantly lower than that of the cement-based composite material in Comparative Example 1. Therefore, it is shown that the thermal conductivity of the cement-based composite material of this invention is significantly reduced, thus realizing the function of improving the thermal insulation effect of the cement-based composite material.

[0085] The data in the table show that the compressive strengths of the cement-based composite materials in Examples 1, 2, 3, 4, and 5 of this invention are 9.1, 9.3, 9.2, 8.9, and 9.4, respectively, which are significantly higher than the compressive strength of the cement-based composite material in Comparative Example 1. Therefore, this indicates that the compressive strength of the cement-based composite material of this invention is significantly improved, and the function of significantly improving the compressive strength of cement-based composite materials and enhancing the overall strength of cement-based composite materials has been achieved.

[0086] The data in the table show that the bulk densities of the cement-based composite materials in Examples 1, 2, 3, 4 and 5 of the present invention are 780, 785, 790, 784 and 793, respectively, which are significantly lower than the bulk density of the cement-based composite material in Comparative Example 1. Therefore, it can be seen that the bulk density of the cement-based composite material of the present invention is significantly reduced, thus achieving the function of reducing the bulk density and increasing the compressive strength of the cement-based composite material.

[0087] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A lightweight, heat-insulating cement-based composite material, characterized in that, The material comprises the following components by weight: 40-60 parts cement matrix, 20-35 parts lightweight aggregate, 5-12 parts polymer modifier, and 0.3-0.5 parts functional additive. The cement matrix is ​​sulfoaluminate cement or silicate cement. The lightweight aggregate includes hollow glass microspheres with a particle size of 0.1-0.5 mm, expanded perlite with a particle size of 0.5-2 mm, and surface-modified aerogel particles. The aerogel particles are silica aerogel or silicon carbide aerogel, and the surface area of ​​the aerogel particles is 600-700 m². 2 / g, the aerogel particles have a pore size of 40~50nm, the polymer modifier is an acrylate-styrene copolymer emulsion, the solid content of the acrylate-styrene copolymer emulsion is 45~50%, the glass transition temperature of the acrylate-styrene copolymer emulsion is -10℃~15℃, and the functional additives include cellulose ether thickener, polycarboxylic acid water-reducing agent, and nano alumina dispersion; The mass ratio of hollow glass microspheres to expanded perlite is 1.5-2.5:

1. The aerogel particles are pretreated with silane coupling agent KH-570, and the surface grafting rate of the aerogel particles after pretreatment is 85-95%. The aerogel particles have a core-shell structure, with a core of silica aerogel and a shell of hydrophobically modified titanium dioxide coating, the thickness of which is 50-200 nm. In the core-shell structure of the aerogel particles, the titanium dioxide coating undergoes in-situ ceramicization treatment to form a micron-sized protrusion structure with a protrusion height of 0.5-2 μm and a density of 30-50 protrusions / μm. 2 It is used to enhance the mechanical bonding force with the cement matrix.

2. The lightweight thermally insulating cement-based composite material according to claim 1, characterized in that: The hollow glass microspheres account for 10-25 parts by weight of the total lightweight aggregate, the expanded perlite accounts for 5-15 parts by weight of the total lightweight aggregate, and the surface-modified aerogel particles account for 3-8 parts by weight of the total lightweight aggregate.

3. A method for preparing a lightweight thermally insulating cement-based composite material, applicable to the lightweight thermally insulating cement-based composite material described in claim 2, characterized in that, The preparation method of this cement-based composite material includes the following steps: Step S1, Lightweight aggregate pretreatment: Place the aerogel particles in a vacuum impregnation tank, inject 5-10% by weight of silane coupling agent ethanol solution, maintain at -0.1MPa for 30-60min, and dry under normal pressure to obtain surface-modified aerogel particles for later use. Step S2, Slurry mixing: Mix the cement matrix, 60% water, polycarboxylate superplasticizer and cellulose ether thickener for 5-10 minutes to form cement matrix slurry one; Step S3, Gradual Incorporation: Hollow glass microspheres and expanded perlite are added sequentially to cement-based slurry one. After stirring at low speed for 3 minutes, surface-modified aerogel particles and remaining water are added. Cement-based slurry two is formed by stirring at high speed for 5 minutes. The low-speed stirring is 200-400 rpm and the high-speed stirring is 800-1200 rpm. Step S4: Inject acrylate-styrene copolymer emulsion into cement-based slurry II, and cure it by microwave radiation at 40-60℃ for 10-20 minutes with a microwave radiation power of 300-500W to form cement-based slurry III. Step S5: After the cement-based slurry is injected into the mold, it is vibrated to compact it and then cured at a humidity of ≥95% and a temperature of 25±2℃.

4. The method for preparing a lightweight thermally insulating cement-based composite material according to claim 3, characterized in that: The cementitious slurry contains a three-dimensional steel fiber network, which accounts for 1.5-3% of the total material composition. The steel fibers are 6-12 mm long and 0.2-0.5 mm in diameter. The steel fibers are coated with zinc phosphate and embedded in the cementitious matrix in an X-shaped cross-weaving pattern. The mesh spacing of the steel fibers is 10-15 mm.

5. The method for preparing a lightweight thermally insulating cement-based composite material according to claim 4, characterized in that: The steel fiber network forms a gradient density distribution in the composite material: the fiber density in the region 0-5 mm from the surface is 120-150 fibers / dm. 3 The 5-15mm range has 80-100 roots / dm 3 Core area ≤50 roots / dm 3 .

6. The method for preparing a lightweight thermally insulating cement-based composite material according to claim 3, characterized in that: The microwave radiation curing in step S4 uses gradient power control: 500W for the first 5 minutes, 300W for the next 5-15 minutes, and switches to 200W for the last 2 minutes before final curing.

7. The method for preparing a lightweight thermally insulating cement-based composite material according to claim 3, characterized in that: In step S4, during the microwave radiation curing process, nitrogen protective gas flow is injected simultaneously at a flow rate of 5-10 L / min, so that a Si3N4 passivation layer is formed on the aerogel surface.

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