Composite thermal insulation block filled with aerogel-supported foamed concrete and its preparation method

Abstract

The present invention provides a composite thermal insulation block filled with aerogel-loaded foam concrete and a preparation method thereof. The composite thermal insulation block comprises: a concrete hollow block, comprising a closed bottom surface and a side surface perpendicular to the bottom surface; the bottom surface and the side surface form a cavity; an aerogel-loaded foam concrete block is filled in the cavity; the bottom surface of the aerogel-loaded foam concrete block abuts the bottom surface of the hollow concrete block; a gap is left between the side surface of the aerogel-loaded foam concrete block and the side surface of the hollow concrete block; the height of the aerogel-loaded foam concrete block is lower than the depth of the cavity; and a foam concrete adhesive layer is filled in the gap and covers the top surface of the aerogel-loaded foam concrete block. The technical problem to be solved is to provide a composite thermal insulation block with a compressive strength of more than 3.5 MPa and a thermal conductivity of less than 0.20 W / (m·k), and how to obtain the composite thermal insulation block so that it is more suitable for practical use.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a composite thermal insulation building block filled with aerogel-loaded foam concrete and a preparation method thereof. Background Art

[0002] With the comprehensive advancement and continuous deepening of building energy conservation, there is an urgent need for different forms of insulation systems, and energy conservation and structural integration have become important directions for the development and application of structural systems. Self-insulating concrete blocks, as the main wall material for energy-saving and structural integration systems, have been one of the key development directions in my country's building block field in recent years. In the existing technology, by filling the holes of hollow concrete blocks with foam concrete, its thermal performance can be improved, making it a self-insulating block with integrated structure and insulation, which can meet the energy-saving construction standards of buildings in different regions of my country. However, the internally filled foam concrete insulation material still cannot meet the performance requirements of high strength and low thermal conductivity at the same time.

[0003] Silica aerogel has excellent thermal insulation properties and is currently being used to develop a variety of building materials, including aerogel felts, boards, coatings, and building blocks. However, the inherent hydrophilicity and mechanical properties of silica aerogel greatly limit its application in cement-based building materials. The preparation of aerogel cement-based building materials generally relies on simple physical doping, which does not significantly improve the thermal performance of the insulation material and limits the doping level. Large amounts of aerogel aerogel addition can significantly reduce the mechanical properties of the product. Summary of the Invention

[0004] The main purpose of the present invention is to provide a composite thermal insulation building block filled with aerogel-loaded foam concrete and a preparation method thereof. The technical problem to be solved is to provide a composite thermal insulation building block with a compressive strength of more than 3.5 MPa and a thermal conductivity of less than 0.20 W / (m·k), and how to obtain the composite thermal insulation building block so that it is more suitable for practical use.

[0005] The purpose of the present invention and the technical problem solved are achieved by adopting the following technical solutions. According to the present invention, a composite thermal insulation building block filled with aerogel-loaded foam concrete is proposed, which comprises:

[0006] A hollow concrete block comprising a closed bottom surface and side surfaces perpendicular to the bottom surface; the bottom surface and the side surfaces form a cavity;

[0007] An aerogel-loaded foam concrete block is filled in the cavity; the bottom surface of the aerogel-loaded foam concrete block abuts against the bottom surface of the hollow concrete block; a gap is left between the side surface of the aerogel-loaded foam concrete block and the side surface of the hollow concrete block; the height of the aerogel-loaded foam concrete block is lower than the depth of the cavity;

[0008] A foam concrete adhesive layer is filled in the gap and covers the top surface of the aerogel-loaded foam concrete block.

[0009] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0010] Preferably, in the aforementioned composite thermal insulation block, the concrete hollow block is selected from one of ordinary concrete hollow blocks, lightweight aggregate concrete small hollow blocks, autoclaved fly ash hollow blocks and fly ash concrete small hollow blocks.

[0011] Preferably, in the aforementioned composite thermal insulation building block, the cavity of the hollow concrete building block is provided with a plurality of dividing surfaces perpendicular to the bottom surface, dividing the cavity into 1 to 4 rows of holes.

[0012] Preferably, in the aforementioned composite thermal insulation building block, the aerogel-loaded foam concrete block refers to a foam concrete block in which silica aerogel particles are loaded in the micropores; and the volume filling ratio of the silica aerogel particles in the aerogel-loaded foam concrete block is 40 to 75%.

[0013] Preferably, in the aforementioned composite thermal insulation building block, the silica aerogel particles have a hydrophobic surface; and the water absorption rate of the aerogel-loaded foam concrete block is 5-10%.

[0014] Preferably, in the aforementioned composite thermal insulation building block, the thermal conductivity of the aerogel-loaded foam concrete block at 25° C. is 0.05 to 0.08 W / (m·k).

[0015] Preferably, the dry density of the aerogel-loaded foam concrete block in the aforementioned composite thermal insulation block is 600-750 kg / m 3 .

[0016] Preferably, in the aforementioned composite thermal insulation building block, the aerogel-loaded foam concrete block has a 28d compressive strength of 3.0 to 4.5 MPa.

[0017] Preferably, in the aforementioned composite thermal insulation building block, the foam concrete adhesive layer has a thermal conductivity of 0.14 to 0.18 W / (m·k), a water absorption of 10 to 15%, and a compressive strength of 3.0 to 4.5 MPa.

[0018] Preferably, in the aforementioned composite thermal insulation building block, the thickness of the foam concrete adhesive layer is 2 to 3 cm.

[0019] The purpose of the present invention and the solution to the technical problem are also achieved by adopting the following technical solutions. According to the present invention, a method for preparing a composite thermal insulation building block filled with aerogel-loaded foam concrete comprises the following steps:

[0020] 1) preparing a silica hydrosol; immersing a foamed concrete block in the hydrosol, so that the silica hydrosol penetrates into the micropores of the foamed concrete block;

[0021] 2) aging the block impregnated with the hydrosol in step 1), performing surface hydrophobic modification, drying, and curing to obtain aerogel-loaded foamed concrete;

[0022] 3) Taking a hollow concrete block; the hollow concrete block includes a closed bottom surface and side surfaces perpendicular to the bottom surface; the bottom surface and the side surfaces form a cavity; cutting the aerogel-loaded foam concrete into blocks of a size adapted to the cavity, and filling the blocks into the cavity; leaving a gap between the side surfaces of the blocks and the side surfaces of the cavity; and the height of the blocks being lower than the depth of the cavity;

[0023] 4) preparing foamed concrete slurry, filling it into the gap between the cavity and the block, and covering the top surface of the block; smoothing the foamed concrete slurry on the top surface to make it level with the side of the cavity; and curing to obtain a composite thermal insulation block filled with aerogel-loaded foamed concrete.

[0024] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0025] Preferably, in the aforementioned method, the immersion in step 1) is to immerse the 7-day-old foamed concrete block in silica hydrosol for 0.5 to 2 hours.

[0026] Preferably, in the aforementioned method, the aging in step 2) refers to keeping the block after being immersed in the hydrosol at room temperature for 12 to 24 hours.

[0027] Preferably, in the aforementioned method, the surface hydrophobic modification in step 2) refers to subjecting the aged block to solution replacement under a vacuum state, wherein the vacuum degree is 0.001 to 0.0005 MPa; the replacement solution is selected from at least one of n-hexane, tert-butanol, ethanol and methanol; and the replacement time is 2 to 4 hours.

[0028] Preferably, in the aforementioned method, the drying in step 2) refers to keeping the surface hydrophobically modified block under supercritical carbon dioxide drying conditions for 6 to 8 hours.

[0029] Preferably, in the aforementioned method, the curing in step 2) refers to keeping the dried block under natural conditions for 7 to 28 days.

[0030] Preferably, in the aforementioned method, the concrete hollow blocks in step 3) are selected from one of ordinary concrete hollow blocks, lightweight aggregate concrete small hollow blocks, autoclaved fly ash hollow blocks and fly ash concrete small hollow blocks; and the curing age of the concrete hollow blocks is 7 to 28 days.

[0031] Preferably, in the aforementioned method, the gap in step 3) is 2 to 3 cm.

[0032] Preferably, in the aforementioned method, the curing in step 4) refers to keeping the filled block under natural conditions for 7 to 14 days.

[0033] By means of the above technical solution, the composite thermal insulation building block filled with aerogel-loaded foam concrete and the preparation method thereof proposed in the present invention have at least the following advantages:

[0034] 1. The present invention provides a composite thermal insulation building block filled with aerogel-loaded foam concrete and a preparation method thereof. The cavity of a hollow concrete building block is filled with aerogel-loaded foam concrete, and the surface of the aerogel particles is hydrophobically modified. Specifically, hydrophobic aerogel is loaded into the micropores of the foam concrete to obtain an aerogel-loaded foam concrete block; the aerogel-loaded foam concrete block is then filled into the cavity of the hollow concrete building block. The pores in the foam concrete are filled with micron / nanoscale silica aerogel particles, which significantly reduce the thermal conductivity of the foam concrete, thereby improving the overall thermal insulation performance of the composite building block. The composite building block is a novel structural energy-saving integrated building wall material.

[0035] 2. The composite thermal insulation building block filled with aerogel-loaded foam concrete and its preparation method provided by the present invention effectively balances the performance indicators of thermal conductivity and strength of aerogel-loaded foam concrete. By microscopically loading silica aerogel particles in the micropores of the foam concrete, the foam concrete and silica aerogel are organically combined into a whole, thereby significantly improving the thermal insulation performance of the aerogel-loaded foam concrete while also maintaining a high compressive strength.

[0036] 3. The composite thermal insulation building block filled with aerogel-loaded foam concrete and its preparation method provided by the present invention can adjust the volume filling ratio of aerogel particles in foam concrete by controlling the impregnation process time, and by controlling the thermal conductivity of the aerogel itself. The thermal conductivity of the thermal insulation building block can be adjusted from these two dimensions. This can produce wall materials that meet the energy-saving standards for buildings in different regions of my country, and has broad application market prospects.

[0037] 4. The composite thermal insulation building block filled with aerogel-loaded foam concrete and its preparation method provided by the present invention have high strength, low water absorption, good thermal insulation, simple and fast production process, and are suitable for large-scale production and application. They can be widely used in the exterior walls and self-insulating walls of green buildings, ultra-low energy consumption and zero energy consumption buildings.

[0038] 5. The composite thermal insulation building block filled with aerogel-loaded foam concrete and its preparation method provided by the present invention can utilize a variety of cement-based materials to prepare composite building blocks with integrated structural insulation, greatly improving the thermal performance of the building blocks and solving the problem of the same lifespan of insulation materials and buildings.

[0039] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the composite thermal insulation building block structure filled with aerogel-loaded foam concrete proposed by the present invention - longitudinal section;

[0041] Figure 2 Schematic diagram of the structure of a composite thermal insulation building block filled with aerogel-loaded foam concrete - transverse section according to one embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the structure of a composite thermal insulation building block filled with aerogel-loaded foam concrete - a transverse section according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] To further illustrate the technical means and effects of the present invention to achieve the intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the specific implementation, structure, characteristics, and effects of the composite thermal insulation block filled with aerogel-loaded foam concrete and its preparation method according to the present invention.

[0044] The present invention proposes a composite thermal insulation building block filled with aerogel-loaded foam concrete, as shown in the attached Figure 1 To the attached Figure 3 As shown, it includes:

[0045] A hollow concrete block 1 comprises a closed bottom surface and side surfaces perpendicular to the bottom surface; the bottom surface and the side surfaces form a cavity;

[0046] An aerogel-loaded foamed concrete block 3 is filled in the cavity; the bottom surface of the aerogel-loaded foamed concrete block abuts against the bottom surface of the hollow concrete block; a gap is left between the side surface of the aerogel-loaded foamed concrete block and the side surface of the hollow concrete block; the height of the aerogel-loaded foamed concrete block is lower than the depth of the cavity;

[0047] The foamed concrete adhesive layer 2 fills the gap and covers the top surface of the aerogel-loaded foamed concrete block.

[0048] Preferably, the concrete hollow blocks are selected from one of ordinary concrete hollow blocks, lightweight aggregate concrete small hollow blocks, autoclaved fly ash hollow blocks and fly ash concrete small hollow blocks.

[0049] Preferably, the cavity of the hollow concrete block is provided with a plurality of dividing surfaces perpendicular to the bottom surface, dividing the cavity into 1 to 4 rows of holes.

[0050] As attached Figure 3 Shown is a composite insulation block filled with aerogel-loaded foam concrete, prepared using a concrete hollow block with four rows of holes as a frame.

[0051] Preferably, the aerogel-loaded foam concrete block refers to a foam concrete block in which silica aerogel particles are loaded in micropores; and the volume filling ratio of the silica aerogel particles in the aerogel-loaded foam concrete block is 40 to 75%.

[0052] In the foamed concrete block, the foamed concrete material forms a porous skeleton network structure, also known as micropores; the silica aerogel fills the micropores. The small units in the foamed concrete material and the small units in the silica aerogel material are independent of each other and are staggered.

[0053] The volume filling ratio is calculated by dividing the volume of the silica aerogel particles by the volume of the aerogel-loaded foam concrete block.

[0054] Preferably, the silica aerogel particles have a hydrophobic surface; and the water absorption rate of the aerogel-loaded foam concrete block is 5-10%.

[0055] Preferably, the thermal conductivity of the aerogel-loaded foam concrete block at 25° C. is 0.05 to 0.08 W / (m·k).

[0056] Preferably, the dry density of the aerogel-loaded foam concrete block is 600-750 kg / m 3 .

[0057] Preferably, the 28d compressive strength of the aerogel-loaded foam concrete block is 3.0-4.5 MPa.

[0058] Preferably, the thermal conductivity of the foam concrete adhesive layer is 0.14-0.18 W / (m·k), the water absorption is 10-15%, and the compressive strength is 3.0-4.5 MPa.

[0059] The test temperature of the thermal conductivity of the foam concrete adhesive layer is 25°C.

[0060] Thermal conductivity of the foamed concrete adhesive layer The thickness of the foamed concrete adhesive layer is 2 to 3 cm.

[0061] The present invention also provides a method for preparing a composite thermal insulation building block filled with aerogel-loaded foam concrete, which comprises the following steps:

[0062] 1) preparing a silica hydrosol; immersing a foamed concrete block in the hydrosol, so that the silica hydrosol penetrates into the micropores of the foamed concrete block;

[0063] 2) aging the block impregnated with the hydrosol in step 1), performing surface hydrophobic modification, drying, and curing to obtain aerogel-loaded foamed concrete;

[0064] 3) Taking a hollow concrete block; the hollow concrete block includes a closed bottom surface and side surfaces perpendicular to the bottom surface; the bottom surface and the side surfaces form a cavity; cutting the aerogel-loaded foam concrete into blocks of a size adapted to the cavity, and filling the blocks into the cavity; leaving a gap between the side surfaces of the blocks and the side surfaces of the cavity; and the height of the blocks being lower than the depth of the cavity;

[0065] 4) preparing foamed concrete slurry, filling it into the gap between the cavity and the block, and covering the top surface of the block; smoothing the foamed concrete slurry on the top surface to make it level with the side of the cavity; and curing to obtain a composite thermal insulation block filled with aerogel-loaded foamed concrete.

[0066] Preferably, the immersion in step 1) is to immerse the 7-day-old foam concrete block in silica hydrosol for 0.5 to 2 hours.

[0067] Preferably, the aging in step 2) refers to keeping the block immersed in the hydrosol at room temperature for 12 to 24 hours.

[0068] The impregnation process time can be adjusted according to the volume of the bulk material. Generally, when the bulk material is small, the impregnation process time can be selected to be shorter, such as 12 hours; when the bulk material is large, the impregnation process time can be selected to be longer, such as 24 hours.

[0069] Preferably, the surface hydrophobic modification in step 2) refers to performing solution replacement on the aged block under vacuum, wherein the vacuum degree is 0.001 to 0.0005 MPa; the replacement solution is selected from at least one of n-hexane, tert-butanol, ethanol and methanol; and the replacement time is 2 to 4 hours.

[0070] Preferably, the drying in step 2) refers to keeping the surface hydrophobically modified block under supercritical carbon dioxide drying conditions for 6 to 8 hours.

[0071] The drying condition is drying at 6-8 MPa under 99.5% mass concentration of carbon dioxide.

[0072] Preferably, the curing in step 2) refers to keeping the dried block under natural conditions for 7 to 28 days.

[0073] Preferably, in step 3), the hollow concrete blocks are selected from one of ordinary hollow concrete blocks, small hollow lightweight aggregate concrete blocks, autoclaved fly ash hollow blocks, and small hollow fly ash concrete blocks; and the curing age of the hollow concrete blocks is 7 to 28 days.

[0074] Preferably, the gap in step 3) is 2 to 3 cm.

[0075] Preferably, the curing in step 4) refers to keeping the filled block under natural conditions for 7 to 14 days.

[0076] The technical solution of the present invention is described in more detail below with more specific examples. The raw materials and reagents used are all commercially available products unless otherwise specified; and the performance testing methods used are all conventional testing methods in the art.

[0077] Example 1

[0078] The hydrosol was prepared by a two-step acid-base catalysis method using tetraethyl orthosilicate as a silicon source, and its solid content was controlled to be 20% by mass.

[0079] The foam concrete block with a size of 370 mm × 180 mm × 180 mm was used, and its thermal conductivity was 0.18 W / (m·k), water absorption was 10%, and compressive strength was 3.5 MPa.

[0080] The foamed concrete block was immersed in the hydrosol for 0.5 hours through a vacuum impregnation process and then removed. The block was aged at room temperature for 24 hours to form a gel. The block was then replaced with a 99% ethanol solution at a vacuum of 0.005 MPa for 2 hours to perform hydrophobic modification.

[0081] The hydrophobically modified concrete blocks were placed in a supercritical carbon dioxide environment at a concentration of 99.5% and a pressure of 6 MPa for 8 hours to produce aerogel-loaded foamed concrete. The silica aerogel particles had a thermal conductivity of 0.013 to 0.015 W / (m·k), and the aerogel-loaded foamed concrete had a thermal conductivity of 0.072 W / (m·k).

[0082] After natural curing for 7 days, it was placed in the cavity of a 28d concrete load-bearing hollow block with a size of 390mm×190mm×190mm.

[0083] A foamed concrete slurry was prepared to fill the gaps between the sides of the hollow blocks and the sides of the aerogel-loaded foamed concrete, and to smooth out any depressions on the top surface of the aerogel-loaded foamed concrete. The slurry had the following proportions, by mass: 60% Portland cement, 39% fly ash, and 1% foaming agent; and a water-cement ratio of 0.4.

[0084] The above-mentioned integral hollow building blocks filled with aerogel-loaded foam concrete and caulked with foam concrete slurry were cured under natural conditions for 7 days to obtain a composite thermal insulation building block filled with aerogel-loaded foam concrete with low thermal conductivity and high strength.

[0085] The performance test of the aerogel-loaded foam concrete described in this embodiment was conducted in accordance with the test method specified in JG / T266-2011 "Foamed Concrete"; the thermal conductivity of the composite insulation block was tested in accordance with the thermal conductivity test method in GB / T10294-2008 "Insulating materials - Determination of steady-state thermal resistance and related properties - Guarded hot plate method"; the test results are shown in Table 1.

[0086] Example 2

[0087] Same as Example 1. The following changes were made: the aging time of the block after impregnation with the hydrosol was 18 h; the process conditions for supercritical carbon dioxide drying were a carbon dioxide concentration of 99.5%, a drying pressure of 6 MPa, and a drying time of 6 h; the thermal conductivity of the silica aerogel particles was 0.015 to 0.018 W / (m·k); and the thermal conductivity of the aerogel-loaded foamed concrete was 0.075 W / (m·k).

[0088] The test results of the performance of the aerogel-loaded foam concrete and the thermal conductivity coefficient of the composite thermal insulation building block described in this embodiment are shown in Table 1.

[0089] The test results of the performance of the aerogel-loaded foam concrete and the thermal conductivity coefficient of the composite thermal insulation building block described in this embodiment are shown in Table 1.

[0090] Example 3

[0091] Same as Example 1. The following changes were made: the foamed concrete block was immersed in the hydrosol for 2 hours; after immersion, it was aged at room temperature for 12 hours; the supercritical carbon dioxide drying process conditions were a carbon dioxide concentration of 99.5%, a drying pressure of 8 MPa, and a drying time of 7 hours; the thermal conductivity of the silica aerogel particles was 0.015 to 0.018 W / (m·k); and the thermal conductivity of the aerogel-loaded foamed concrete was 0.058 W / (m·k).

[0092] The test results of the performance of the aerogel-loaded foam concrete and the thermal conductivity coefficient of the composite thermal insulation building block described in this embodiment are shown in Table 1.

[0093] Example 4

[0094] Same as Example 1. The following changes were made: the foamed concrete block was immersed in the hydrosol for 2 hours; after immersion, it was aged at room temperature for 24 hours; the supercritical carbon dioxide drying process conditions were a carbon dioxide concentration of 99.5%, a drying pressure of 8 MPa, and a drying time of 8 hours; the thermal conductivity of the silica aerogel particles was 0.015 to 0.018 W / (m·k); and the thermal conductivity of the aerogel-loaded foamed concrete was 0.038 W / (m·k).

[0095] The test results of the performance of the aerogel-loaded foam concrete and the thermal conductivity coefficient of the composite thermal insulation building block described in this embodiment are shown in Table 1.

[0096] Comparative Example 1

[0097] The foam concrete block with a size of 370 mm × 180 mm × 180 mm was used, and its thermal conductivity was 0.18 W / (m·k), water absorption was 10%, and compressive strength was 3.5 MPa.

[0098] The aerogel was placed in the cavity of a 390 mm x 190 mm x 190 mm 28-day concrete load-bearing hollow block. A foamed concrete slurry (same as in Example 1) was prepared to fill the gap between the side of the hollow block and the side of the aerogel-loaded foamed concrete, and to smooth the depression on the top surface of the aerogel-loaded foamed concrete.

[0099] The integral hollow building blocks filled with aerogel-loaded foamed concrete and caulked with foamed concrete slurry were cured under natural conditions for 7 days to obtain a composite thermal insulation building block.

[0100] The test results of the performance of the foam concrete described in this comparative example and the thermal conductivity coefficient of the composite thermal insulation building block are shown in Table 1.

[0101] Table 1

[0102]

[0103] The product test data of the above-mentioned embodiments and comparative examples show that the mechanical properties of the aerogel-loaded foam concrete of Examples 1 to 4 do not change significantly compared with the ordinary foam concrete of Comparative Example 1, while the thermal conductivity and water absorption are greatly reduced, making it have the characteristics of high strength and high thermal insulation performance. The thermal insulation performance of the structural-energy-saving composite insulation building block filled and compounded with the aerogel is also significantly improved, and its performance meets the standard requirements of GB / T8239-2014 "Ordinary Concrete Small Building Blocks".

[0104] The technical features in the claims and / or the specification of the present invention may be combined, and the manner of combination is not limited to the combination obtained by reference in the claims. The technical solutions obtained by combining the technical features in the claims and / or the specification are also within the scope of protection of the present invention.

[0105] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A composite thermal insulation building block filled with aerogel-loaded foam concrete, characterized in that: It includes: A hollow concrete block comprising a closed bottom surface and side surfaces perpendicular to the bottom surface; the bottom surface and the side surfaces form a cavity; An aerogel-loaded foam concrete block is filled in the cavity; the bottom surface of the aerogel-loaded foam concrete block abuts against the bottom surface of the hollow concrete block; a gap is left between the side surface of the aerogel-loaded foam concrete block and the side surface of the hollow concrete block; the height of the aerogel-loaded foam concrete block is lower than the depth of the cavity; a foam concrete binder layer filling the gap and covering the top surface of the aerogel-loaded foam concrete block; The aerogel-loaded foam concrete block refers to a foam concrete block in which silica aerogel particles are loaded in the micropores; the volume filling ratio of the silica aerogel particles in the aerogel-loaded foam concrete block is 40 to 75%; The silica aerogel particles have a hydrophobic surface; the water absorption rate of the aerogel-loaded foam concrete block is 5 to 10%; The thermal conductivity of the aerogel-loaded foam concrete block at 25° C. is 0.05 to 0.08 W / (m·k); The drying method during the preparation of the aerogel-loaded foamed concrete block is to maintain the temperature at 6-8 MPa for 6-8 hours under supercritical carbon dioxide drying conditions.

2. The composite thermal insulation building block according to claim 1, characterized in that: The concrete hollow blocks are selected from one of ordinary concrete hollow blocks, lightweight aggregate concrete small hollow blocks, autoclaved fly ash hollow blocks and fly ash concrete small hollow blocks.

3. The composite thermal insulation building block according to claim 1, characterized in that: The cavity of the hollow concrete block is provided with a plurality of dividing surfaces perpendicular to the bottom surface, dividing the cavity into 1 to 4 rows of holes.

4. The composite thermal insulation building block according to claim 1, characterized in that: The dry density of the aerogel-loaded foam concrete block is 600-750 kg / m 3 .

5. The composite thermal insulation building block according to claim 1, characterized in that: The 28d compressive strength of the aerogel-loaded foam concrete block is 3.0-4.5 MPa.

6. The composite thermal insulation building block according to claim 1, characterized in that: The foam concrete adhesive layer has a thermal conductivity of 0.14-0.18 W / (m·k), a water absorption rate of 10-15%, and a compressive strength of 3.0-4.5 MPa.

7. The composite thermal insulation building block according to claim 1, characterized in that: The thickness of the foam concrete adhesive layer is 2 to 3 cm.

8. A method for preparing a composite thermal insulation building block filled with aerogel-loaded foam concrete, characterized in that: It includes the following steps: 1) preparing a silica hydrosol; immersing a foamed concrete block in the hydrosol, so that the silica hydrosol penetrates into the micropores of the foamed concrete block; 2) aging the block impregnated with the hydrosol in step 1), performing surface hydrophobic modification, drying, and curing to obtain aerogel-loaded foamed concrete; the drying comprises maintaining the surface hydrophobic modified block under supercritical carbon dioxide drying conditions at 6 to 8 MPa for 6 to 8 hours; 3) obtaining a hollow concrete block; the hollow concrete block comprises a closed bottom surface and side surfaces perpendicular to the bottom surface; the bottom surface and the side surfaces form a cavity; cutting the aerogel-loaded foamed concrete into blocks of a size adapted to the cavity, and filling the blocks into the cavity; leaving a gap between the side surfaces of the blocks and the side surfaces of the cavity; and the height of the blocks being lower than the depth of the cavity; 4) preparing foamed concrete slurry, filling it into the gap between the cavity and the block, and covering the top surface of the block; smoothing the foamed concrete slurry on the top surface to make it level with the side surface of the cavity; and curing to obtain a composite thermal insulation block filled with aerogel-loaded foamed concrete; The aerogel-loaded foam concrete block refers to a foam concrete block in which silica aerogel particles are loaded in the micropores; the volume filling ratio of the silica aerogel particles in the aerogel-loaded foam concrete block is 40 to 75%; The silica aerogel particles have a hydrophobic surface; the water absorption rate of the aerogel-loaded foam concrete block is 5 to 10%; The thermal conductivity of the aerogel-loaded foam concrete block at 25° C. is 0.05-0.08 W / (m·k).

9. The method according to claim 8, characterized in that In step 1), the immersion is to immerse the 7-day-old foamed concrete block in silica hydrosol for 0.5 to 2 hours.

10. The method according to claim 8, characterized in that Step 2) The aging process refers to keeping the block immersed in the hydrosol at room temperature for 12 to 24 hours.

11. The method according to claim 8, characterized in that Step 2) The surface hydrophobic modification refers to replacing the aged block with a solution under vacuum, wherein the vacuum degree is 0.001 to 0.0005 MPa; the replacement solution is selected from at least one of n-hexane, tert-butanol, ethanol and methanol; and the replacement time is 2 to 4 hours.

12. The method according to claim 8, characterized in that Step 2) The curing refers to keeping the dried block under natural conditions for 7 to 28 days.

13. The method according to claim 8, characterized in that Step 3) The concrete hollow blocks are selected from one of ordinary concrete hollow blocks, lightweight aggregate concrete small hollow blocks, autoclaved fly ash hollow blocks and fly ash concrete small hollow blocks; the curing age of the concrete hollow blocks is 7 to 28 days.

14. The method according to claim 8, characterized in that Step 3) The gap is 2 to 3 cm.

15. The method according to claim 8, characterized in that Step 4) The curing refers to keeping the filled block under natural conditions for 7 to 14 days.

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