Autoclaved aerated concrete and its preparation method

Abstract

This invention discloses an autoclaved aerated concrete (AAC), belonging to the field of building materials technology. An AAC comprises the following components in parts by weight: 45-55 parts high-silica fly ash; 10-15 parts rice husk ash; 12-18 parts silicate cement; 8-12 parts quicklime; 3-5 parts desulfurized gypsum; 0.05-0.12 parts aluminum powder paste; 0.3-1.2 parts reinforcing and foam-stabilizing agent; and 45-55 parts water. The reinforcing and foam-stabilizing agent comprises basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant, and the mass ratio of basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is (15-40):(1-10):1. The AAC of this invention exhibits excellent compressive strength, thermal conductivity, and durability.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to an autoclaved aerated concrete and its preparation method. Background Technology

[0002] Autoclaved aerated concrete (AAC) is a lightweight, porous silicate product made from calcareous materials (quicklime, cement) and siliceous materials (quartz sand, river sand, fly ash, and silica-containing tailings, etc.) as basic components, with appropriate amounts of gypsum as modifiers. The process involves grinding the calcium and silica materials into a slurry, mixing, adding aluminum powder paste and other foaming agents, and then pouring, pre-curing, cutting, and autoclaving. AAC possesses numerous advantages, including lightweight, thermal insulation, fire resistance, sound insulation, and environmental friendliness. Therefore, AAC has become a new type of energy-saving and waste-utilizing wall material that has been vigorously promoted and applied in my country in recent years.

[0003] However, existing technologies suffer from the following bottlenecks: 1. Difficulty in balancing strength and density: Conventional B05 grade products have low compressive strength, which cannot meet the requirements of high-rise infill walls or partial load-bearing structures; increasing strength leads to a sharp increase in density, resulting in a loss of thermal insulation advantages. 2. Uneven pore structure: Air bubbles are prone to merging and collapsing, resulting in large fluctuations in the internal porosity of the product, high thermal conductivity, and poor sound insulation and impermeability. 3. Insufficient durability: Traditional fiber reinforcement is prone to deterioration under high-temperature and high-alkali curing environments, with weak interfacial bonding, and is prone to cracking and water absorption swelling after long-term use. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide autoclaved aerated concrete and its preparation method. The autoclaved aerated concrete of this invention has excellent compressive strength, thermal conductivity, and durability.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides autoclaved aerated concrete, comprising the following raw material components in parts by weight: 45-55 parts high-silica fly ash; 10-15 parts rice husk ash; 12-18 parts silicate cement; 8-12 parts quicklime; 3-5 parts desulfurized gypsum; 0.05-0.12 parts aluminum powder paste; 0.3-1.2 parts foaming agent; 45-55 parts water; The foam stabilizer comprises basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant, and the mass ratio of the basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is (15-40):(1-10):1.

[0006] Preferably, the mass ratio of the basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is (20-35):(3-7):1.

[0007] Preferably, the aspect ratio of the basalt fiber is 600-1800.

[0008] Preferably, the basalt fiber is modified by means of the following method: adding the basalt fiber to water glass and a silane coupling agent and modifying it by vacuum impregnation. Preferably, the silane coupling agent is selected from one or more of γ-glycidoxypropyltrimethoxysilane (KH560), γ-methacryloyloxypropyltrimethoxysilane (KH570), and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH792).

[0009] Preferably, the high-silica fly ash has a SiO2 mass content ≥65%, a Dv50 particle size of 10-25 μm, and a specific surface area of ​​600-800 m². 2 / kg.

[0010] Preferably, the autoclaved aerated concrete further includes a composite mineralizer, which is composed of nano-hydroxyapatite and lithium carbonate in a mass ratio of (3-5):1.

[0011] Preferably, the average particle size of the nano-hydroxyapatite is 50-200 nm.

[0012] Preferably, the mass of the composite mineralizer is 0.1-0.3% of the mass of high-silica fly ash.

[0013] Secondly, the present invention also provides a method for preparing autoclaved aerated concrete, comprising the following steps: (1) Mix high silica fly ash, rice husk ash, silicate cement, quicklime, desulfurized gypsum and water evenly to obtain a base slurry; (2) Add the foam stabilizer to the base slurry and mix evenly, then add aluminum powder paste and mix evenly to obtain the mixed slurry; (3) The mixture slurry is placed in the mold, pre-cured and then autoclaved to obtain autoclaved aerated concrete.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, by simultaneously adding basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant, can regulate the pore structure of the concrete system, making the pores more round, uniform, and closed. This significantly reduces the thermal conductivity of the concrete, improves its sound insulation, and enhances its impermeability, thereby enabling autoclaved aerated concrete to achieve high strength, low thermal conductivity, and high durability at low density. Detailed Implementation

[0015] To better illustrate the purpose, technical solution, and advantages of this application, the following will provide further explanation of this application in conjunction with specific embodiments.

[0016] Unless otherwise specified, the reagents, methods and equipment used in this application are all conventional reagents, methods and equipment in the field.

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0019] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0020] In one embodiment of this application, autoclaved aerated concrete is provided, comprising the following raw material components in parts by weight: 45-55 parts high-silica fly ash; 10-15 parts rice husk ash; 12-18 parts silicate cement; 8-12 parts quicklime; 3-5 parts desulfurized gypsum; 0.05-0.12 parts aluminum powder paste; 0.3-1.2 parts foaming agent; 45-55 parts water; The foam stabilizer comprises basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant, and the mass ratio of the basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is (15-40):(1-10):1.

[0021] High-silica fly ash is rich in active SiO2, which rapidly participates in pozzolanic reaction under alkaline conditions, providing a structural framework in the early stages. Rice husk ash is highly active amorphous SiO2 with a large specific surface area and much higher reactivity than fly ash, continuing to react in the mid-to-late stages, resulting in a more uniform overall pore structure and more stable strength in concrete. Simultaneously, amorphous SiO2 can reduce Ca(OH)2 enrichment, decrease interfacial weak zones, and improve impermeability and frost resistance.

[0022] Quicklime provides high alkalinity, stimulating gas generation in alumina powder and activating the activity of siliceous materials. Silicate cement provides early strength and structural stability. Desulfurized gypsum acts as a retarder and crystal modifier, inhibiting the excessively rapid reaction of aluminates, extending the slurry stabilization time, and preventing green body collapse. Therefore, silicate cement, quicklime, and desulfurized gypsum together form CSH gel and tobermorite precursors, laying the foundation for crystal development during the autoclaving stage.

[0023] In the foam stabilizer, basalt fibers can form a uniform three-dimensional network structure within the green body, inhibiting pore coalescence during the gas generation stage, shrinkage cracking during the curing stage, and thermal stress cracking during the autoclaving stage. Hydroxypropyl starch ether can increase the viscosity and thixotropy of the slurry, slowing down the rise of bubbles and making them less prone to coalescence, thus forming uniform and fine pores. Silicone polyether surfactant can reduce the liquid-gas interfacial tension, stabilize the bubble film, and prevent bubble rupture and interconnected pore formation. Therefore, this invention, by simultaneously adding basalt fibers, hydroxypropyl starch ether, and silicone polyether surfactant, can regulate the pore structure, making the pores more rounded, uniform, and closed. This significantly reduces the thermal conductivity of concrete, improves sound insulation, and enhances impermeability, thereby achieving high strength, low thermal conductivity, and high durability in autoclaved aerated concrete at low density.

[0024] In some embodiments, the mass ratio of basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is (20-35):(3-7):1, for example, it can be 20:3:1, 20:4:1, 20:5:1, 20:6:1, 20:7:1, 25:3:1, 25:4:1, 25:5:1, 25:6:1, 25:7:1, 30:3:1, 30:4:1, 30:5:1, 30:6:1, 30:7:1, 35:3:1, 35:4:1, 35:5:1, 35:6:1, 35:7:1, or a range consisting of any two of these values.

[0025] In some embodiments, the aspect ratio of the basalt fiber is 600-1800, for example, it can be 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1800 or any two of these values.

[0026] In some embodiments, the aspect ratio of the basalt fiber is 1000-1500.

[0027] If the aspect ratio of basalt fibers is too low, the fiber's bridging ability across cracks is insufficient, significantly reducing the reinforcing effect. If the aspect ratio of basalt fibers is too high, the fibers are prone to clumping in the slurry, interfering with the gas generation process, leading to uneven pore structure, cracking of the green body, and performance degradation. Therefore, this invention, by controlling the aspect ratio of basalt fibers, can maximize the bridging toughening and crack resistance enhancement effects while ensuring good fiber dispersion, thereby improving the compressive strength of concrete, as well as enhancing the toughness and durability of concrete.

[0028] In some embodiments, the basalt fibers have an average length of 6-12 mm.

[0029] In some embodiments, the basalt fibers have an average diameter of 12-16 μm.

[0030] In some embodiments, the basalt fiber is modified by adding water glass and silane coupling agent and then modifying it by vacuum impregnation.

[0031] Water glass forms a SiO2 gel coating on the surface of basalt fibers, which is beneficial to improving the alkali resistance and steam erosion resistance of concrete. Silane coupling agents enable chemical bonding between the basalt fibers and the matrix, significantly improving interfacial adhesion. Therefore, this invention, by modifying basalt fibers, not only does not affect gas generation but also significantly improves the integrity and compressive strength of concrete.

[0032] In some embodiments, the silane coupling agent is selected from one or more of γ-glycidoxypropyltrimethoxysilane (KH560), γ-methacryloyloxypropyltrimethoxysilane (KH570), and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH792).

[0033] This invention introduces active amino groups onto the surface of basalt fibers by employing the aforementioned amino-based silane coupling agent. On the one hand, these groups condense with the silanol groups on the fiber surface to form stable chemical bonds; on the other hand, they form hydrogen bonds and chemical bonds with cement-based hydration products. This significantly improves the interfacial compatibility between the fiber and the matrix, increases the interfacial bonding strength, and enhances the stability of the fiber under high-temperature and high-alkali steam curing conditions, preventing the fiber from being eroded and peeled off, and ensuring the continuous and effective reinforcement effect.

[0034] In some embodiments, the Dv50 particle size of the high-silica fly ash is 15-20 μm, for example, it can be 15μm, 16μm, 17μm, 18μm, 9μm, 20μm or any two of these values.

[0035] If the particle size of high-silica fly ash is too large, the fly ash activity is low, the slurry is prone to stratification, resulting in uneven gas generation and insufficient product strength. If the particle size of high-silica fly ash is too small, the slurry viscosity is too high, gas generation is hindered, and grinding costs are high. Therefore, this invention achieves the optimal balance between fly ash activity and slurry processability by controlling the Dv50 particle size of high-silica fly ash, ensuring that autoclaved aerated concrete achieves high strength, uniform porosity, and stable thermal insulation while remaining lightweight.

[0036] In some embodiments, the specific surface area of ​​the rice husk ash is 600-800 m². 2 / kg, for example, could be or 600m 2 / kg, 650m 2 / kg, 700m 2 / kg, 750m 2 / kg, 800m 2 / kg is a range consisting of any two values.

[0037] In some embodiments, the specific surface area of ​​the quicklime is 450-550 m². 2 / kg, for example, could be 450m 2 / kg, 460m 2 / kg, 480m 2 / kg, 500m 2 / kg, 520m 2 / kg, 540m 2 / kg, 550m 2 / kg or a range consisting of any two of these values.

[0038] The particle size distribution described in this invention is typically determined using laser diffraction (laser particle size analyzer), and the specific surface area is determined using the gas adsorption BET method.

[0039] In some embodiments, the autoclaved aerated concrete further includes a composite mineralizer, which is composed of nano-hydroxyapatite and lithium carbonate in a mass ratio of (3-5):1, for example, it can be a range of 3:1, 3.5:1, 4:1, 4.5:1, 5:1 or any two of these values.

[0040] In this invention, nano-hydroxyapatite acts as a crystal growth guide, directing the growth of tobermorite crystals into a needle-like interwoven structure, thereby enhancing the strength and density of concrete and strengthening the interfacial bonding between basalt fibers and the matrix. Lithium carbonate, as a crystal growth accelerator, lowers the crystal nucleation energy barrier, accelerates the hydration reaction of active silicon, shortens autoclaving time, and reduces energy consumption. Therefore, by simultaneously adding nano-hydroxyapatite and lithium carbonate, this invention effectively addresses the shortcomings of traditional single mineralizers, such as "disordered crystal growth and weak interfacial bonding," thus further improving the compressive strength and durability of concrete.

[0041] In some embodiments, the nano-hydroxyapatite has an average particle size of 50-200 nm and a purity of ≥98%, for example, it can be... In some embodiments, the average particle size of the lithium carbonate is ≤10 μm; In some embodiments, the mass of the composite mineralizer is 0.1-0.3% of the mass of high-silica fly ash, for example, it can be 0.1%, 0.12%, 0.14%, 0.16%, 0.2%, 0.22%, 0.25%, 0.28%, or 0.3%. In some embodiments, the mass of the composite mineralizer is 0.15-0.26% of the mass of high-silica fly ash, or a range consisting of any two of these values.

[0042] In some embodiments, the high-silica fly ash has a SiO2 mass content ≥65%, a Dv50 particle size of 10-25 μm, and a specific surface area of ​​600-800 m². 2 / kg.

[0043] The amount of high-silica fly ash used in this invention is 45-55 parts, for example, it can be 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts or any two of these values.

[0044] In some embodiments, the high-silica fly ash has a mass percentage content of 20-50% in autoclaved aerated concrete.

[0045] The amount of rice husk ash used in this invention is 10-15 parts, for example, it can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts or any two of these values.

[0046] In some embodiments, the rice husk ash has a mass percentage content of 5-15% in autoclaved aerated concrete.

[0047] The amount of silicate cement used in this invention is 12-18 parts, for example, it can be 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts or any two of these values.

[0048] In some embodiments, the silicate cement accounts for 6-18% of the mass of the autoclaved aerated concrete.

[0049] The amount of quicklime used in this invention is 8-12 parts, for example, it can be 8 parts, 9 parts, 10 parts, 11 parts, 12 parts or any two of these values.

[0050] In some embodiments, the quicklime content in the autoclaved aerated concrete is 2-10% by mass.

[0051] The amount of desulfurized gypsum used in this invention is 3-5 parts, for example, it can be 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts or any two of these values.

[0052] Preferably, the desulfurized gypsum has a mass percentage content of 0.01-0.09% in the autoclaved aerated concrete.

[0053] The amount of aluminum powder paste used in this invention is 0.05-0.12 parts, for example, it can be 0.05 parts, 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts, 0.10 parts, 0.11 parts, 0.12 parts, or any two of these values.

[0054] The amount of the foam stabilizer described in this invention is 0.3-1.2 parts, for example, it can be 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts, 1.1 parts, 1.2 parts or any two of these values.

[0055] Secondly, the present invention also provides a method for preparing autoclaved aerated concrete, comprising the following steps: (1) Mix high silica fly ash, rice husk ash, silicate cement, quicklime, desulfurized gypsum and water evenly to obtain a base slurry; (2) Add the foam stabilizer to the base slurry and mix evenly, then add aluminum powder paste and mix evenly to obtain the mixed slurry; (3) The mixture slurry is placed in the mold, pre-cured and then autoclaved to obtain autoclaved aerated concrete.

[0056] Example 1 An autoclaved aerated concrete (AAC) comprises the following raw material components in parts by weight: 50 parts high-silica fly ash; 12 parts rice husk ash; 15 parts silicate cement; 10 parts quicklime; 4 parts desulfurized gypsum; 0.10 parts aluminum powder paste; 0.8 parts foaming agent; 50 parts water; The foam-stabilizing agent includes basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant, and the mass ratio of basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is 25:5:1, that is, the mass parts of basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant in autoclaved aerated concrete are 0.64 parts, 0.13 parts, and 0.03 parts, respectively.

[0057] A method for preparing autoclaved aerated concrete includes the following steps: 1. High-silica fly ash (high-silica fly ash with SiO2 mass content ≥65%, Dv50 particle size 20 μm, specific surface area 800 m²) 2 / kg), rice husk ash (Lingshou County Maozhuo Building Materials Co., Ltd.), silicate cement (Lingshou County Xurun Mineral Products Processing Plant), quicklime (Lingshou County Shanchuan Mineral Products Processing Plant), and desulfurized gypsum (Hubei Puhui Building Materials Co., Ltd.) were added to a mixer and dry-mixed at 120 rpm for 6 minutes; then 40℃ warm water was added and stirred at 150 rpm for 20 minutes to obtain the base slurry, with a diffusion degree controlled at 200 mm and a pH value of 12.

[0058] 2. Then add basalt fiber (Tai'an Anfeng New Material Technology Co., Ltd., aspect ratio 1200) and hydroxypropyl starch ether (Shandong Hongquan Chemical Technology Co., Ltd.), and stir at low speed of 50 rpm for 2 minutes; then add silicone polyether surfactant (Shandong Xiongrui Trading Co., Ltd.), and stir at 100 rpm for 40 seconds.

[0059] 3. Gas generation: Add aluminum powder paste (Shandong Huachen Biotechnology Co., Ltd.), stir at 1000 rpm for 25 seconds to obtain a mixed slurry, and then pour it in immediately. Control the gas generation rhythm to prevent bubbles from escaping.

[0060] 4. Pouring and allowing to rest The mixed slurry is injected into the mold and sent to the curing room. It is cured at 50℃ and relative humidity ≥85% for 3 hours until the hardness of the green body is 0.20MPa, thus completing the gas generation and initial setting.

[0061] 5. Demolding and cutting The blank is flipped and demolded, and then precisely cut on six sides to produce blocks / boards of the target specifications. The scraps are recycled and reused.

[0062] 6. Gradient autoclaving (1) Pre-vacuuming: Vacuuming is performed in the autoclave to -0.05MPa and maintained for 15min to remove the air inside the billet and improve the steam permeation efficiency.

[0063] (2) Gradient temperature and pressure increase: First stage: 70℃, 0.4MPa, heating rate 3℃ / min, curing for 2 hours, slow hydration to avoid cracking of the green body; Second stage: 170℃, 1.0MPa, heating rate 2℃ / min, curing for 5h, core hydrothermal synthesis to generate tobermorite crystals; Third stage: 180℃, 1.0MPa, curing for 1.5h to strengthen the crystal structure and improve strength.

[0064] (3) Slow pressure reduction and cooling: the pressure reduction rate is ≤0.05 MPa / min, and the autoclaved aerated concrete is cooled to below 60℃ to avoid temperature stress cracking.

[0065] Examples 2-5 The difference between Examples 2-5 and Example 1 is that the mass ratio of basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is changed.

[0066] Examples 6-9 The difference between Examples 6-9 and Example 1 is that the aspect ratio of the basalt fiber is changed. This invention does not have a particular limitation on the source of the basalt fiber, as long as the purpose of this invention can be achieved.

[0067] Example 10 Example 10 differs from Example 1 in that the basalt fiber is modified. The preparation method is as follows: After drying and pretreatment, the basalt fiber is placed in a vacuum impregnation tank and evacuated to -0.09 MPa for 20 min. Then, a composite modifier system is injected, and the fiber is impregnated under vacuum for 40 min. After decompression and gradient drying and curing, the modified basalt fiber is obtained. The composite modifier system consists of water glass, silane coupling agent, anhydrous ethanol, and deionized water. The mass ratio of water glass to silane coupling agent is 10:1, and the total mass concentration of the modifier system is 20%. The water glass has a modulus of 3.0 and a solid content of 45%. The silane coupling agent is γ-aminopropyltriethoxysilane (KH550).

[0068] Example 11 The difference between Example 11 and Example 10 is that the silane coupling agent is N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH792).

[0069] Example 12 The difference between Example 12 and Example 1 is that the autoclaved aerated concrete further includes a composite mineralizer, which is composed of nano-hydroxyapatite (average particle size of 200 nm) and lithium carbonate in a mass ratio of 4:1.

[0070] Examples 13-14 The difference between Examples 13-14 and Example 12 is that the mass ratio of nano-hydroxyapatite and lithium carbonate is changed.

[0071] Examples 15-16 The difference between Examples 15-16 and Example 12 is that the quality of the composite mineralizer is changed.

[0072] Comparative Examples 1-2 The difference between Comparative Example 1 and Example 1 is that the mass ratio of basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant was changed.

[0073] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that no basalt fiber was added.

[0074] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that hydroxypropyl starch ether was not added.

[0075] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that no silicone polyether surfactant was added.

[0076] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that glass fiber of equal mass is used instead of basalt fiber.

[0077] The components, contents, and parameters of autoclaved aerated concrete are shown in Table 1.

[0078] Table 1 Performance testing: All performance tests were conducted in accordance with the relevant records in GB / T 11969-2020 "Test Methods for Performance of Autoclaved Aerated Concrete".

[0079] The test results are shown in Table 2.

[0080] Table 2 As shown in Table 2, the autoclaved aerated concrete of the present invention has a compressive strength of over 4.8 MPa, a thermal conductivity of less than 0.131 W / (m·k), and a mass loss rate of less than 3.0%, indicating that the autoclaved aerated concrete of the present invention has excellent compressive strength, thermal conductivity, and durability.

[0081] Comparing Comparative Examples 1-2 with Example 1, it can be seen that if the mass ratio of basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is too low or too high, it will have a certain impact on the compressive strength and thermal conductivity of autoclaved aerated concrete. This indicates that controlling the mass ratio of basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant within the range defined by this invention is beneficial to improving the compressive strength, thermal conductivity, and durability of autoclaved aerated concrete.

[0082] Comparing Comparative Examples 3-5 with Example 1, it can be seen that the compressive strength and thermal conductivity of autoclaved aerated concrete are reduced when basalt fiber is not added in Comparative Example 3, hydroxypropyl starch ether is not added in Comparative Example 4, and silicone polyether surfactant is not added in Comparative Example 5. This indicates that only by simultaneously adding basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant can autoclaved aerated concrete simultaneously possess excellent compressive strength, thermal conductivity, and durability.

[0083] Comparing Comparative Example 6 with Example 1, it can be seen that the use of other fibers in Comparative Example 6, combined with hydroxypropyl starch ether and silicone polyether surfactant, will have a certain impact on the compressive strength and thermal conductivity of autoclaved aerated concrete. This shows that not all fibers can be combined with hydroxypropyl starch ether and silicone polyether surfactant to make autoclaved aerated concrete have both excellent compressive strength and thermal conductivity.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An autoclaved aerated concrete, characterized in that, The components include the following parts by weight: 45-55 parts high-silica fly ash; 10-15 parts rice husk ash; 12-18 parts silicate cement; 8-12 parts quicklime; 3-5 parts desulfurized gypsum; 0.05-0.12 parts aluminum powder paste; 0.3-1.2 parts foaming agent; 45-55 parts water; The foam stabilizer comprises basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant, and the mass ratio of the basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is (15-40):(1-10):

1.

2. The autoclaved aerated concrete as described in claim 1, characterized in that, The mass ratio of the basalt fiber, hydroxypropyl starch ether, and silicone polyether surfactant is (20-35):(3-7):

1.

3. The autoclaved aerated concrete as described in claim 1, characterized in that, The aspect ratio of the basalt fiber is 600-1800.

4. The autoclaved aerated concrete as described in claim 1, characterized in that, The basalt fiber is modified by adding water glass and silane coupling agent and then modifying it by vacuum impregnation.

5. The autoclaved aerated concrete as described in claim 4, characterized in that, The silane coupling agent is selected from one or more of γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

6. The autoclaved aerated concrete as described in claim 1, characterized in that, The high-silica fly ash has a SiO2 content ≥65% by mass, a Dv50 particle size of 10-25 μm, and a specific surface area of ​​600-800 m². 2 / kg.

7. The autoclaved aerated concrete as described in claim 1, characterized in that, The autoclaved aerated concrete also includes a composite mineralizer, which is composed of nano-hydroxyapatite and lithium carbonate in a mass ratio of (3-5):

1.

8. The autoclaved aerated concrete as described in claim 7, characterized in that, The average particle size of the nano-hydroxyapatite is 50-200 nm.

9. The autoclaved aerated concrete as described in claim 7, characterized in that, The mass of the composite mineralizer is 0.1-0.3% of the mass of high-silica fly ash.

10. A method for preparing autoclaved aerated concrete as described in any one of claims 1-9, characterized in that, Includes the following steps: (1) Mix high silica fly ash, rice husk ash, silicate cement, quicklime, desulfurized gypsum and water evenly to obtain base slurry; (2) Add the foam stabilizer to the base slurry and mix evenly, then add aluminum powder paste and mix evenly to obtain the mixed slurry; (3) The mixture slurry is placed in the mold, pre-cured and then autoclaved to obtain autoclaved aerated concrete.

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