Vitrified microsphere thermal insulation concrete and preparation method thereof

Abstract

The application discloses vitrified microsphere thermal insulation concrete and a preparation method thereof, and belongs to the field of concrete building materials. Raw materials of the concrete include cement, stone, sand, vitrified microsphere, hydroxyl-terminated polydimethylsiloxane grafted fly ash, ceramic powder, water reducing agent and water. The concrete has good frost resistance, and the bonding strength with smooth round steel bars after 200 freeze-thaw cycles is 3.1-3.4 MPa, and the bonding strength with deformed steel bars after 200 freeze-thaw cycles is 4.5-4.7 MPa.

Description

Technical Field

[0001] This invention relates to a vitrified microsphere thermal insulation concrete and its preparation method, belonging to the field of concrete building materials. Background Technology

[0002] One important means of achieving energy conservation and emission reduction in buildings is to take thermal insulation measures to reduce energy consumption during heating. Approximately 90% of multi-story and high-rise buildings both domestically and internationally are reinforced concrete structures. Concrete, as the main building material, has poor thermal insulation performance, and the internal temperature of the building is easily affected by the environment. To ensure the internal temperature of the building and reduce energy consumption, thermal insulation layers need to be added to the inner and outer layers of the concrete structure to form a composite wall insulation system.

[0003] Vitrified microspheres are a lightweight, porous inorganic material formed by the expansion of perlite ore through high-temperature calcination. Their interior is filled with closed or open pores, and their surface, due to high-temperature melting, forms a smooth, glassy layer (i.e., "vitrification"), hence the name.

[0004] The porous structure of vitrified microspheres endows them with excellent thermal insulation performance, making them suitable for preparing thermal insulation concrete (such as external wall insulation layers and underfloor heating backfill layers), thereby reducing building energy consumption. At the same time, the low density of vitrified microspheres (usually 80-300 kg / m³) can significantly reduce the density of concrete, and the lightweight concrete prepared is suitable for high-rise buildings, large-span structures and other weight-sensitive scenarios.

[0005] Due to the limitations of the vitrification process itself, the surface of vitrified microspheres is prone to defects. Incomplete vitrification can lead to extremely small voids on the surface. Even if the surface defects of the vitrified microspheres can be eliminated, some of the microspheres will break during mortar mixing, and moisture will still enter the concrete through the voids, causing freeze-thaw damage.

[0006] The problem of water penetration can be solved by optimizing the proportion of gel materials. Appropriately increasing the amount of active admixtures such as silica fume and fly ash in the concrete composition can improve the density of the concrete, fill the gaps between microspheres, reduce permeability, and thus improve the frost resistance of the concrete.

[0007] In practical applications, it has been found that although the freeze-thaw resistance of concrete can be improved to some extent, the bond strength between concrete and steel bars will still decrease significantly after multiple freeze-thaw cycles. Furthermore, the crack resistance of concrete decreases due to the increased proportion of silica fume and fly ash. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the existing technology. By mixing perlite, potassium feldspar, fluorite and aluminum silicate fiber, and then preparing vitrified microspheres by gradient melting vitrification, and then combining them with hydroxyl-terminated polydimethylsiloxane grafted fly ash, the two are used as raw material components of thermal insulation concrete, which improves the frost resistance of concrete and its crack resistance.

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

[0010] A type of vitrified microsphere thermal insulation concrete, wherein the raw materials of the concrete include cement, gravel, sand, vitrified microspheres, hydroxyl-terminated polydimethylsiloxane-grafted fly ash, ceramic powder, water-reducing agent, and water, and the mass ratio of each raw material is 225-275:150-200:125-175:200-250:30-50:30-40:0.9-1.1:250-300.

[0011] The following are further improvements to the above technical solution:

[0012] The cement is P·O42.5 silicate cement;

[0013] The gravel is a 5-25mm continuous gradation;

[0014] The sand is medium sand from Zone II;

[0015] The ceramic powder has a fineness of 200 mesh;

[0016] The water-reducing agent is a polycarboxylate water-reducing agent;

[0017] The method for preparing the vitrified microspheres is as follows:

[0018] Perlite is crushed in a crusher to control the particle size to 0.45-0.55 mm. The crushed perlite is then heat-treated at 385-420℃ to remove crystal water and adsorbed water until the water content is 0.45-0.55 wt%. Potassium feldspar and fluorite are crushed in a pulverizer to a particle size of 80-150 mesh to obtain a mixed powder. The crushed perlite, mixed powder, and aluminosilicate fibers are then mixed evenly in a mixer to obtain a molten mixture. The mixture is placed in an expansion furnace and softened in the first stage at 885-895℃ for 4-6 seconds. Then, the temperature is adjusted to 940-950℃ for the second stage of softening for 3-5 seconds. Next, the water of crystallization is vaporized at 1040-1060℃ for 6-8 seconds. Finally, vitrification is carried out at 1240-1260℃ for 3-5 seconds. After vitrification, the mixture is cooled to obtain vitrified microspheres.

[0019] The mass ratio of potassium feldspar to fluorite is 2.5-3.5:1;

[0020] The mass ratio of the crushed perlite, mixed powder, and aluminosilicate fiber is 9-11:1.8-2.2:0.9-1.1.

[0021] The aluminum silicate fiber has a diameter of 2.5-3.5 μm and a length of 0.20-0.30 mm.

[0022] The method for preparing the hydroxyl-terminated polydimethylsiloxane-grafted fly ash is as follows:

[0023] Fly ash is mixed with acetone to obtain a fly ash dispersion. The dispersion is then heated to 52-57°C, and hydroxyl-terminated polydimethylsiloxane is added and stirred for 15-25 minutes. After stirring, γ-aminopropyltriethoxysilane is added, and the temperature is maintained at 52-57°C. Stirring continues for 100-150 minutes. After stirring, the mixture is filtered and dried to obtain hydroxyl-terminated polydimethylsiloxane-grafted fly ash.

[0024] The mass ratio of fly ash, acetone, hydroxyl-terminated polydimethylsiloxane, and γ-aminopropyltriethoxysilane is 9-11:140-160:2.8-3.2:0.9-1.1.

[0025] The fly ash is Class I fly ash.

[0026] The preparation method of the vitrified microsphere thermal insulation concrete is as follows:

[0027] After mixing cement, gravel, sand, vitrified microspheres, hydroxyl-terminated polydimethylsiloxane-grafted fly ash, ceramic powder, water-reducing agent, and water according to specified quantities in the raw materials, and then curing according to standard conditions, a vitrified microsphere thermal insulation concrete is obtained.

[0028] Compared with the prior art, the present invention achieves the following beneficial effects:

[0029] This invention involves uniformly mixing perlite, potassium feldspar, fluorite, and aluminosilicate fibers at their respective specific particle sizes or lengths. By utilizing the different melting temperatures of perlite, potassium feldspar, and fluorite, combined with a gradient melting vitrification process, vitrified microspheres are prepared. This not only optimizes the internal structure of the vitrified microspheres but also eliminates surface defects caused by the vitrification process. The high melting point of the aluminosilicate fibers ensures that their morphology does not change within the vitrified microspheres, providing support for the internal structure and increasing the bonding strength between the microspheres and other gelling materials in concrete. The fly ash particles, rich in silanol and aluminol hydroxyl groups, are grafted with hydroxyl-terminated polydimethylsiloxane under the action of γ-aminopropyltriethoxysilane. Experiments show that vitrified microspheres and hydroxyl-terminated polydimethylsiloxane-grafted fly ash, when used as raw material components in concrete, can effectively improve the freeze-thaw resistance of concrete, especially enhancing the bond strength between concrete and reinforcing steel after multiple freeze-thaw cycles. Furthermore, it can also improve the crack resistance of concrete.

[0030] The concrete of this invention has excellent thermal insulation effect. The thermal conductivity of the concrete was tested according to the method in GB / T 10295-2008 and found to be 0.11-0.12 W / (m·K).

[0031] The concrete of this invention has high mechanical strength. According to the method in GB / T 50081-2019, the compressive strength, flexural strength and elastic modulus of the concrete were tested. The compressive strength was 17.1-17.2 MPa, the flexural strength was 5.9-6.2 MPa and the elastic modulus was 13.5-13.8 GPa.

[0032] The concrete of this invention exhibits good bond strength with reinforcing steel. According to the methods in GB / T 50152-2012 and JGJ / T 152-2019, the bond strength between the concrete and plain round steel bars and deformed steel bars was tested. The bond strength with plain round steel bars was 3.5-3.8 MPa, and the bond strength with deformed steel bars was 5.6-5.8 MPa.

[0033] The concrete of this invention exhibits good frost resistance. Following the method described in GB / T 50082-2009, a rapid freezing method was used to conduct frost resistance tests. The tests measured the thermal conductivity, elastic modulus retention rate, and interfacial bond strength with reinforcing steel after 200 freeze-thaw cycles. The thermal conductivity after 200 freeze-thaw cycles was 0.13-0.14 W / (m·K), the elastic modulus retention rate was 72.8-73.5%, the bond strength with plain round reinforcing steel was 3.1-3.4 MPa, and the bond strength with deformed reinforcing steel was 4.5-4.7 MPa. Detailed Implementation Example 1

[0034] A type of vitrified microsphere thermal insulation concrete, the raw materials of which include cement, gravel, sand, vitrified microspheres, hydroxyl-terminated polydimethylsiloxane-grafted fly ash, ceramic powder, water-reducing agent, and water, with the mass ratio of each raw material being 250:175:150:225:40:35:1:275.

[0035] The cement is P·O42.5 silicate cement;

[0036] The gravel is a 5-25mm continuous gradation;

[0037] The sand is medium sand from Zone II;

[0038] The ceramic powder has a fineness of 200 mesh;

[0039] The water-reducing agent is a polycarboxylate water-reducing agent;

[0040] The method for preparing the vitrified microspheres is as follows:

[0041] Perlite was crushed in a crusher to control the particle size of the crushed particles to 0.50 mm. The crushed perlite was then heat-treated at 400℃ to remove crystal water and adsorbed water until the water content was 0.5 wt%. Potassium feldspar and fluorite were crushed in a pulverizer to a particle size of 100 mesh to obtain a mixed powder. The crushed perlite, mixed powder, and aluminum silicate fiber were mixed evenly in a mixer to obtain a molten mixture. The molten mixture was placed in an expansion furnace and softened in the first stage at 890℃ for 5 seconds. Then, the temperature was adjusted to 945℃ for the second stage of softening for 4 seconds. Crystal water was then vaporized at 1050℃ for 7 seconds. Finally, vitrification was performed at 1250℃ for 4 seconds. After vitrification, the mixture was cooled to obtain vitrified microspheres.

[0042] The mass ratio of potassium feldspar to fluorite is 3:1;

[0043] The mass ratio of the crushed perlite, mixed powder, and aluminum silicate fiber is 10:2:1.

[0044] The aluminum silicate fiber has a diameter of 3 μm and a length of 0.25 mm.

[0045] The method for preparing the hydroxyl-terminated polydimethylsiloxane-grafted fly ash is as follows:

[0046] Fly ash was mixed with acetone to obtain a fly ash dispersion. The dispersion was then heated to 55°C, and hydroxyl-terminated polydimethylsiloxane was added and stirred for 20 minutes. After stirring, γ-aminopropyltriethoxysilane was added, and the temperature was maintained at 55°C. Stirring was continued for 120 minutes. After stirring, the mixture was filtered and dried to obtain hydroxyl-terminated polydimethylsiloxane-grafted fly ash.

[0047] The mass ratio of fly ash, acetone, hydroxyl-terminated polydimethylsiloxane, and γ-aminopropyltriethoxysilane is 10:150:3:1.

[0048] The fly ash is Class I fly ash.

[0049] The preparation method of the vitrified microsphere thermal insulation concrete is as follows:

[0050] After mixing cement, gravel, sand, vitrified microspheres, hydroxyl-terminated polydimethylsiloxane-grafted fly ash, ceramic powder, water-reducing agent, and water according to specified quantities in the raw materials, and then curing according to standard conditions, a vitrified microsphere thermal insulation concrete is obtained. Example 2

[0051] A type of vitrified microsphere thermal insulation concrete, the raw materials of which include cement, gravel, sand, vitrified microspheres, hydroxyl-terminated polydimethylsiloxane-grafted fly ash, ceramic powder, water-reducing agent, and water, with the mass ratio of each raw material being 225:150:125:200:30:30:0.9:250.

[0052] The cement is P·O42.5 silicate cement;

[0053] The gravel is a 5-25mm continuous gradation;

[0054] The sand is medium sand from Zone II;

[0055] The ceramic powder has a fineness of 200 mesh;

[0056] The water-reducing agent is a polycarboxylate water-reducing agent;

[0057] The method for preparing the vitrified microspheres is as follows:

[0058] Perlite was crushed in a crusher to control the particle size of the crushed particles to 0.45 mm. The crushed perlite was then heat-treated at 385℃ to remove crystal water and adsorbed water until the water content was 0.45 wt%. Potassium feldspar and fluorite were crushed in a pulverizer to obtain a mixed powder with a particle size of 80 mesh. The crushed perlite, mixed powder, and aluminum silicate fiber were mixed evenly in a mixer to obtain a molten mixture. The molten mixture was placed in an expansion furnace and softened in the first stage at 885℃ for 6 seconds. Then, the temperature was adjusted to 950℃ for the second stage of softening for 3 seconds. Crystal water was then vaporized at 1040℃ for 8 seconds. Finally, vitrification was carried out at 1260℃ for 3 seconds. After vitrification, the mixture was cooled to obtain vitrified microspheres.

[0059] The mass ratio of potassium feldspar to fluorite is 2.5:1;

[0060] The mass ratio of the crushed perlite, mixed powder, and aluminosilicate fiber is 9:1.8:0.9.

[0061] The aluminum silicate fiber has a diameter of 2.5 μm and a length of 0.20 mm.

[0062] The method for preparing the hydroxyl-terminated polydimethylsiloxane-grafted fly ash is as follows:

[0063] Fly ash was mixed with acetone to obtain a fly ash dispersion. The dispersion was then heated to 52°C, and hydroxyl-terminated polydimethylsiloxane was added and stirred for 25 minutes. After stirring, γ-aminopropyltriethoxysilane was added, and the temperature was maintained at 52°C. Stirring was continued for 150 minutes. After stirring, the mixture was filtered and dried to obtain hydroxyl-terminated polydimethylsiloxane-grafted fly ash.

[0064] The mass ratio of fly ash, acetone, hydroxyl-terminated polydimethylsiloxane, and γ-aminopropyltriethoxysilane is 9:140:2.8:0.9.

[0065] The fly ash is Class I fly ash.

[0066] The preparation method of the vitrified microsphere thermal insulation concrete is as follows:

[0067] After mixing cement, gravel, sand, vitrified microspheres, hydroxyl-terminated polydimethylsiloxane-grafted fly ash, ceramic powder, water-reducing agent, and water according to specified quantities in the raw materials, and then curing according to standard conditions, a vitrified microsphere thermal insulation concrete is obtained. Example 3

[0068] A type of vitrified microsphere thermal insulation concrete, the raw materials of which include cement, gravel, sand, vitrified microspheres, hydroxyl-terminated polydimethylsiloxane-grafted fly ash, ceramic powder, water-reducing agent, and water, with the mass ratio of each raw material being 275:200:175:250:50:40:1.1:300.

[0069] The cement is P·O42.5 silicate cement;

[0070] The gravel is a 5-25mm continuous gradation;

[0071] The sand is medium sand from Zone II;

[0072] The ceramic powder has a fineness of 200 mesh;

[0073] The water-reducing agent is a polycarboxylate water-reducing agent;

[0074] The method for preparing the vitrified microspheres is as follows:

[0075] Perlite was crushed in a crusher to control the particle size of the crushed particles to 0.55 mm. The crushed perlite was then heat-treated at 420℃ to remove crystal water and adsorbed water until the water content was 0.55 wt%. Potassium feldspar and fluorite were crushed in a pulverizer to a particle size of 150 mesh to obtain a mixed powder. The crushed perlite, mixed powder, and aluminosilicate fiber were mixed evenly in a mixer to obtain a molten mixture. The molten mixture was placed in an expansion furnace and softened in one stage at 895℃ for 4 seconds. Then, the temperature was adjusted to 940℃ for a second stage of softening for 5 seconds. Crystal water was then vaporized at 1060℃ for 6 seconds. Finally, vitrification was performed at 1240℃ for 5 seconds. After vitrification, the mixture was cooled to obtain vitrified microspheres.

[0076] The mass ratio of potassium feldspar to fluorite is 3.5:1;

[0077] The mass ratio of the crushed perlite, mixed powder, and aluminosilicate fiber is 11:2.2:1.1.

[0078] The aluminum silicate fiber has a diameter of 3.5 μm and a length of 0.30 mm.

[0079] The method for preparing the hydroxyl-terminated polydimethylsiloxane-grafted fly ash is as follows:

[0080] Fly ash was mixed with acetone to obtain a fly ash dispersion. The dispersion was then heated to 57°C, and hydroxyl-terminated polydimethylsiloxane was added and stirred for 15 minutes. After stirring, γ-aminopropyltriethoxysilane was added, and the temperature was maintained at 57°C. Stirring was continued for 100 minutes. After stirring, the mixture was filtered and dried to obtain hydroxyl-terminated polydimethylsiloxane-grafted fly ash.

[0081] The mass ratio of fly ash, acetone, hydroxyl-terminated polydimethylsiloxane, and γ-aminopropyltriethoxysilane is 11:160:3.2:1.1.

[0082] The fly ash is Class I fly ash.

[0083] The preparation method of the vitrified microsphere thermal insulation concrete is as follows:

[0084] After mixing cement, gravel, sand, vitrified microspheres, hydroxyl-terminated polydimethylsiloxane-grafted fly ash, ceramic powder, water-reducing agent, and water according to specified quantities in the raw materials, and then curing according to standard conditions, a vitrified microsphere thermal insulation concrete is obtained.

[0085] Comparative Example 1

[0086] Unlike Example 1, the preparation method of vitrified microspheres was changed to the following steps:

[0087] Perlite was crushed in a crusher to control the particle size of the crushed particles to 0.50 mm. The crushed perlite was then heat-treated at 400℃ to remove crystal water and adsorbed water until the water content was 0.5 wt%. It was then placed in an expansion furnace and softened at 945℃ for 4 seconds. Crystal water was then vaporized at 1050℃ for 7 seconds. Finally, it was vitrified at 1250℃ for 4 seconds. After vitrification, it was cooled to obtain vitrified microspheres.

[0088] The remaining steps are the same, and vitrified microsphere thermal insulation concrete is prepared.

[0089] Comparative Example 2

[0090] Unlike Example 1, untreated fly ash was used instead of hydroxyl-terminated polydimethylsiloxane-grafted fly ash, while keeping the amount and other steps unchanged, to prepare vitrified microsphere insulating concrete.

[0091] Test Example 1 Thermal Insulation Performance Test

[0092] The thermal conductivity of the vitrified microsphere thermal insulation concrete prepared in Examples 1-3 and Comparative Examples 1-2 was tested according to the method in GB / T 10295-2008, and the results are shown in Table 1.

[0093] Table 1

[0094]

[0095] Examples 1-3 involve mixing perlite, potassium feldspar, fluorite, and aluminum silicate fiber, then preparing vitrified microspheres using gradient melt vitrification, and finally combining them with hydroxyl-terminated polydimethylsiloxane-grafted fly ash. Both are used as raw material components for thermal insulation concrete, which can achieve excellent thermal insulation effect and low thermal conductivity.

[0096] The perlite in Comparative Example 1 was vitrified using a relatively simple method. When the resulting glass microspheres were used as a raw material component of thermal insulation concrete, they caused a significant decrease in the thermal insulation performance of the concrete and a substantial increase in the thermal conductivity.

[0097] Comparative Example 2 used untreated fly ash instead of hydroxyl-terminated polydimethylsiloxane-grafted fly ash, which had a smaller impact on the thermal insulation performance of concrete and a smaller decrease in thermal conductivity.

[0098] Test Example 2 Mechanical Property Test

[0099] The vitrified microsphere thermal insulation concrete prepared in Examples 1-3 and Comparative Examples 1-2 was tested for compressive strength, flexural strength, and modulus of elasticity according to the method in GB / T 50081-2019. The results are shown in Table 2.

[0100] Table 2

[0101]

[0102] Examples 1-3 involve mixing perlite, potassium feldspar, fluorite, and aluminum silicate fiber, then preparing vitrified microspheres using gradient melt vitrification, and finally combining them with hydroxyl-terminated polydimethylsiloxane-grafted fly ash. Both are used as raw material components for thermal insulation concrete, which can give the concrete superior mechanical properties, with high compressive strength, flexural strength, and modulus of elasticity.

[0103] The perlite in Comparative Example 1 was vitrified using a relatively simple method. When the prepared glass microspheres were used as a raw material component of thermal insulation concrete, the mechanical properties of the concrete would be severely reduced due to the deterioration of its internal structure and surface defects. The compressive strength, flexural strength and elastic modulus would all be severely reduced.

[0104] Comparative Example 2 showed that using untreated fly ash instead of hydroxyl-terminated polydimethylsiloxane-grafted fly ash resulted in a decrease in the mechanical properties of concrete, but the degree of decrease was small.

[0105] Test Example 3: Interfacial Adhesion Performance Test

[0106] The vitrified microsphere thermal insulation concrete prepared in Examples 1-3 and Comparative Examples 1-2 was tested for bond strength with plain round steel bars and deformed steel bars according to the methods in GB / T 50152-2012 and JGJ / T 152-2019. The results are shown in Table 3.

[0107] Table 3

[0108]

[0109] Examples 1-3 involve mixing perlite, potassium feldspar, fluorite, and aluminum silicate fiber, then preparing vitrified microspheres using gradient melt vitrification, and finally combining them with hydroxyl-terminated polydimethylsiloxane-grafted fly ash. Both are used as raw material components of thermal insulation concrete, which can improve the bonding performance between concrete and steel bars, and has high bonding strength with both plain round steel bars and deformed steel bars.

[0110] The perlite in Comparative Example 1 was vitrified using a relatively simple method. When the resulting glass microspheres were used as a raw material component of thermal insulation concrete, the bonding performance between the concrete and the reinforcing steel deteriorated, and the bonding strength with both plain round steel bars and deformed steel bars decreased significantly.

[0111] Comparative Example 2 shows that using untreated fly ash instead of hydroxyl-terminated polydimethylsiloxane-grafted fly ash leads to a deterioration in the bond performance between concrete and steel reinforcement, with a significant decrease in the bond strength with both plain round steel bars and deformed steel bars.

[0112] Test Example 4: Antifreeze Performance Test

[0113] The vitrified microsphere thermal insulation concrete prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to frost resistance tests using the rapid freezing method according to the method in GB / T 50082-2009. The thermal conductivity, elastic modulus retention rate, and interfacial adhesion with steel bars were tested after 200 freeze-thaw cycles. The results are shown in Table 4.

[0114] Table 4

[0115]

[0116] Examples 1-3 show that by mixing perlite, potassium feldspar, fluorite, and aluminum silicate fiber, vitrified microspheres are prepared using gradient melt vitrification. These microspheres are then combined with hydroxyl-terminated polydimethylsiloxane-grafted fly ash. Both are used as raw material components for thermal insulation concrete, which can improve the concrete's frost resistance. Even after multiple freeze-thaw cycles, the concrete can still maintain a low thermal conductivity and a high elastic modulus. In addition, it can maintain a high bond strength with steel bars, especially the bond strength with plain round steel bars, which basically does not decrease.

[0117] The perlite in Comparative Example 1 was vitrified using a relatively simple method. When the resulting glass microspheres were used as a raw material component of thermal insulation concrete, the concrete's frost resistance decreased, its thermal conductivity increased significantly, its elastic modulus retention rate decreased significantly, and the bond strength between the concrete and the reinforcing steel decreased significantly.

[0118] In Comparative Example 2, using untreated fly ash instead of hydroxyl-terminated polydimethylsiloxane-grafted fly ash resulted in a decrease in the frost resistance of concrete, a significant increase in thermal conductivity, a certain degree of decrease in the retention rate of elastic modulus, and a certain degree of decrease in the bond strength between concrete and steel reinforcement.

Claims

1. A glazed thermal concrete, characterized in that, Raw materials of the concrete include cement, stone, sand, vitrified microbead, hydroxyl-terminated polydimethylsiloxane grafted fly ash, ceramic powder, water reducing agent and water; The mass ratio of the cement, stone, sand, vitrified microbead, hydroxyl-terminated polydimethylsiloxane grafted fly ash, ceramic powder, water reducing agent and water is 225-275:150-200:125-175:200-250:30-50:30-40:0.9-1.1:250-300; The preparation method of the vitrified microbead is: The perlite is crushed, and then the crushed perlite is heat treated, the crushed perlite is ready for use, the potassium feldspar and fluorite are crushed to obtain a mixed powder, the crushed perlite, the mixed powder and the aluminum silicate fiber are uniformly mixed in a mixer to obtain a to-be-melted mixture, and the to-be-melted mixture is placed in an expansion furnace to perform one-stage softening, two-stage softening, crystallization water gasification and vitrification, respectively, and the vitrified microbead is obtained after cooling after the vitrification is completed; The crushed perlite is crushed in a crusher, and the particle size after crushing needs to be controlled to be 0.45-0.55 mm; The heat treatment method is heat treatment at 385-420 ℃ to remove crystallization water and adsorbed water, and the heat treatment needs to be processed until the water content is 0.45-0.55 wt%; The potassium feldspar and fluorite are crushed, and the particle size needs to be crushed to 80-150 mesh; The one-stage softening method is one-stage softening by controlling the temperature to be 885-895 ℃, and the residence time of one-stage softening is 4-6 s; The two-stage softening method is two-stage softening by adjusting the temperature to be 940-950 ℃, and the residence time of two-stage softening is 3-5 s; The crystallization water gasification method is crystallization water gasification at 1040-1060 ℃, and the residence time of crystallization water gasification is 6-8 s; The vitrification method is vitrification at 1240-1260 ℃, and the residence time of the vitrification stage is 3-5 s; The mass ratio of the potassium feldspar and fluorite is 2.5-3.5:1; The mass ratio of the crushed perlite, the mixed powder and the aluminum silicate fiber is 9-11:1.8-2.2:0.9-1.1; The diameter of the aluminum silicate fiber is 2.5-3.5 μm, and the length is 0.20-0.30 mm; The preparation method of the hydroxyl-terminated polydimethylsiloxane grafted fly ash is: The fly ash is mixed and stirred with acetone to obtain a fly ash dispersion liquid, then the dispersion liquid is heated, hydroxyl-terminated polydimethylsiloxane is added and stirred, after the stirring is completed, γ-aminopropyl triethoxysilane is added and stirred, and after the stirring is completed, filtration and drying are performed to obtain the hydroxyl-terminated polydimethylsiloxane grafted fly ash; The mass ratio of the fly ash, acetone, hydroxyl-terminated polydimethylsiloxane and γ-aminopropyl triethoxysilane is 9-11:140-160:2.8-3.2:0.9-1.

1.

2. The vitrified microbead insulation concrete according to claim 1, characterized in that: In the raw materials of the concrete, the cement is P·O42.5 Portland cement; The stone is 5-25 mm continuous gradation; The sand is a sand in zone II; The ceramic powder has a fineness of 200 mesh; The water reducing agent is a polycarboxylic acid water reducing agent. 3.The vitrified microsphere thermal insulation concrete according to claim 1, characterized in that: In the preparation method of the hydroxyl-terminated polydimethylsiloxane grafted fly ash, the method of heating the dispersion liquid is heating to 52-57 DEG C. The stirring time required for adding the hydroxyl-terminated polydimethylsiloxane and stirring is 15-25 min. The method of continuing to stir after adding the gamma-aminopropyl triethoxysilane is to continue to stir at a temperature of 52-57 DEG C, and the stirring time is 100-150 min. 4.The vitrified microsphere thermal insulation concrete according to claim 1, characterized in that: In the preparation method of the hydroxyl-terminated polydimethylsiloxane grafted fly ash, the fly ash is a Class I fly ash. 5.A preparation method of the vitrified microsphere thermal insulation concrete according to claim 1, characterized in that: The preparation method is to mix cement, stones, sand, vitrified microspheres, hydroxyl-terminated polydimethylsiloxane grafted fly ash, ceramic powder, water reducing agent and water in a specified mass, and then to obtain the vitrified microsphere thermal insulation concrete through standard curing.

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