Autoclaved aerated concrete self-insulation building block and preparation method thereof

Abstract

The invention relates to an autoclaved aerated concrete self-heat-preservation building block and a preparation method thereof, and belongs to the technical field of new building materials, the autoclaved aerated concrete self-heat-preservation building block comprises aggregate and water, and the water-material ratio is 0.4-0.6; the aggregate is prepared from the following components in parts by mass: 50 to 80 parts of fly ash or quartz sand, 4 to 20 parts of cement, 5 to 20 parts of quick lime, 0 to 5 parts of gypsum, 0.05 to 0.15 part of aluminum paste and 2 to 3 parts of a special additive for self-insulation. The invention also discloses a preparation method of the autoclaved aerated concrete self-insulation building block. The autoclaved aerated concrete self-insulation building block has the advantages of high strength and low heat conductivity.

Description

Technical Field

[0001] The invention belongs to the technical field of new building materials, and specifically relates to an autoclaved aerated concrete self-insulating building block and a preparation method thereof, which has the advantages of high strength and low thermal conductivity. Background Art

[0002] Autoclaved Aerated Concrete (AAC) is a silicate product with a lightweight and porous structure, which is made of siliceous materials (cement and quartz sand) and calcareous materials (lime, gypsum) as the main raw materials. It uses the chemical reaction of the gas generating agent with its components in the slurry to generate gas. It is formed through a process of mixing, pouring, static stopping, cutting, high-pressure curing, and unloading.

[0003] With the improvement of national building energy conservation goals and the continuous improvement of technological innovation levels, the technology of integrated wall insulation and structure has become another new technical development direction for energy conservation of building envelope structures. It is a major change in traditional building design and wall insulation construction technology. Through the implementation of integrated wall insulation and structure technology, the transformation of secondary construction of building insulation to synchronous construction is realized; the transformation of fire protection of building materials to fire protection of building structures; the transformation of the entire life cycle of building insulation to the same life as the wall structure is realized, effectively avoiding the occurrence of engineering quality and fire safety problems of external wall insulation technology.

[0004] Therefore, technical personnel in this field are committed to developing a high-strength, low-thermal-conductivity autoclaved aerated concrete self-insulating building block and a preparation method thereof for the problems of high thermal conductivity and poor mechanical properties of traditional autoclaved aerated concrete. Summary of the invention

[0005] In view of the shortcomings of the existing autoclaved aerated concrete technology, the technical problem to be solved by the present invention is to provide a high-strength, low-thermal-conductivity autoclaved aerated concrete self-insulating building block that can be used for self-bearing construction and a preparation method thereof. It is suitable for use as a single homogeneous inorganic self-insulating building exterior wall that meets 75% energy saving requirements in severe cold and cold regions.

[0006] The first purpose of the present invention is to overcome the problem of too high thermal conductivity of B07, B06 and B05 autoclaved aerated concrete in the prior art, and to provide a high-strength, low-thermal-conductivity autoclaved aerated concrete self-insulating building block.

[0007] The technical solution adopted by the present invention to solve the technical problem is: an autoclaved aerated concrete self-insulating building block, comprising aggregate and water, wherein the water-to-aggregate ratio is 0.4-0.6; the aggregate comprises, by weight, 50-80 parts of ground fly ash or quartz sand, 4-20 parts of cement, 5-20 parts of quicklime, 0-5 parts of gypsum, 0.05-0.15 parts of aluminum paste and 2-3 parts of a special self-insulating admixture, wherein the special self-insulating admixture comprises a water reducer, an air entraining agent, a foam stabilizer, a hydrophobic agent, a surfactant and a nano whisker in a weight ratio of (1-3): 1: (0.5-1): (1-5): (0.5-2): (2-5).

[0008] Preferably, the autoclaved aerated concrete self-insulating building block comprises 60-80 parts of fly ash, 10-20 parts of cement, 10-20 parts of quicklime, 0-5 parts of gypsum, 0.05-0.15 parts of aluminum paste and 2-3 parts of special self-insulating admixture, in parts by mass, wherein the water-to-material ratio is 0.45-0.6.

[0009] Preferably, the autoclaved aerated concrete self-insulating building block comprises 50-75 parts of ground quartz sand, 10-20 parts of cement, 10-20 parts of quicklime, 0-3 parts of gypsum, 0.05-0.15 parts of aluminum paste and 2-3 parts of a special self-insulating admixture, in parts by mass, wherein the water-to-material ratio is 0.4-0.55.

[0010] Preferably, the SiO2 content in Class I fly ash is ≥55%, the Al2O3 content is ≥18%, the Fe content is ≤1%, and the S content is ≤1%.

[0011] Preferably, the quartz sand can be natural sand or aeolian sand, wherein the SiO2 content is ≥75%, the mud content is ≤3%, and the average particle size is 180-200 meshes.

[0012] Preferably, the cement is ordinary Portland cement with a strength grade of 42.5 MPa.

[0013] Preferably, the quicklime digestion time is 8 to 14 minutes, the digestion temperature is ≤90° C., the effective CaO content is ≥75%, and the residue on the 80 μm square hole sieve is ≤12.0%.

[0014] Preferably, the active aluminum content in the aluminum paste is ≥65%, the 0.75 mm sieve residue is ≤2.5%, and the 30 min gas evolution rate is ≥98%.

[0015] Preferably, the gypsum is desulfurized gypsum with a CaSO4 content of ≥90%.

[0016] Preferably, the water reducer is one of naphthalene-based high-efficiency water reducer, polycarboxylic acid-based high-efficiency water reducer, aliphatic high-efficiency water reducer, and humate-based water reducer; Preferably, the air entraining agent is one or more of rosin soap, rosin thermal polymer, sodium alkylbenzene sulfonate, sodium alkyl sulfate, fatty alcohol polyoxyethylene ether, sodium fatty alcohol polyoxyethylene sulfonate, triterpenoid saponin, and modified lignin sulfonate; Preferably, the foam stabilizer is one or more of polyacrylate, polyvinyl alcohol, polyoxyethylene alcohol, gelatin, gum arabic, polydimethylsiloxane, modified silicone oil, and aluminum sulfate; Preferably, the water repellent is one or more of methyl trimethylsiloxane, polydimethylsiloxane, silicone acrylic emulsion, silicone resin emulsion, waterborne polyurethane emulsion, epoxy resin emulsion, calcium stearate, aluminum sulfate, aluminum chloride, zinc chloride, zinc sulfate, paraffin, and microcrystalline wax; Preferably, the surfactant is one or more of sodium fatty acid, sodium laurate, sodium dodecyl sulfate, sodium alkylbenzene sulfonate, cocamidopropyl betaine, cocamidopropyl hydroxysulfobetaine, polyoxyethylene ether, sulfate ester salt, sulfonate, quaternary ammonium salt, polyoxyethylene-polyoxypropylene block copolymer; Preferably, the nano whiskers are one or more of aluminum oxide nano whiskers, calcium phosphate nano whiskers, calcium silicate nano whiskers, calcium carbonate nano whiskers, calcium zeolite whiskers, sodium zeolite whiskers, and fumed silica.

[0017] The second purpose of the present invention is to provide a method for preparing a high-strength, low-thermal-conductivity autoclaved aerated concrete self-insulating block in order to solve the technical problem that the thermal conductivity of B07, B06 and B05 aerated concrete blocks in the prior art is too high.

[0018] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing an autoclaved aerated concrete self-insulating building block, comprising the following steps: S1. Make a slurry of 50-80 parts of fly ash, 0-5 parts of gypsum and water, or make a slurry of 50-80 parts of quartz sand, 0-5 parts of gypsum and water, control the diffusion degree to 290-380 mm, put it into a mixer, and then add 2-3 parts of self-insulation special admixture, 4-20 parts of cement, and 5-20 parts of quicklime in sequence, stir for 3-5 minutes, control the diffusion degree to 150-220 mm, wherein the slurry water-to-material ratio is 0.4-0.6, and the pouring temperature is controlled at 37-42 ° C to obtain slurry; S2. Add 0.05 to 0.15 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 to 45 seconds to obtain a finished slurry; S3. The finished slurry obtained in step S2 is poured into a mold and placed in a pre-curing chamber at 45°C for 120 to 180 minutes to form a volume-stable autoclaved aerated concrete semi-finished product; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. The semi-finished autoclaved aerated concrete obtained in step S4 is put into an autoclave for curing, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 min, and a blowdown is performed; the constant temperature pressure is 0.9 to 1.2 MPa, the temperature is 175 to 192 ° C, the time is 6 to 12 h, and the blowdown is performed every 1 h; the pressure relief time is 1.5 to 2 h, the temperature drops to below 80 ° C, and the single-side autoclave door is opened to obtain autoclaved aerated concrete self-insulating blocks.

[0019] Beneficial effects of the present invention: The autoclaved aerated concrete self-insulating building block provided by the present invention has a special self-insulating admixture added into its formula. Under the premise of adding a low amount, the thermal conductivity of the autoclaved aerated concrete self-insulating building block is greatly reduced, the compressive strength of the autoclaved aerated concrete self-insulating building block is improved, and the durability and sound insulation performance of the autoclaved aerated concrete self-insulating building block are also improved.

[0020] The composite gasification technology is used in the autoclaved aerated concrete self-insulating blocks, which makes the product have small pore size, round pore shape, thick pore wall, and many micropores. The addition of nanomaterials and whiskers fills the tiny cracks of the capillary pores, blocks the defects in the microporous structure, forms a large number of closed pores, and improves the closed-pore rate of the product. The optimization of the microstructure is one of the important reasons for improving the macroscopic appearance compressive strength and thermal performance of the autoclaved aerated concrete self-insulating blocks. DETAILED DESCRIPTION

[0021] The present invention is described in detail below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should belong to the scope of protection of the present invention.

[0022] Prepare the materials: Fly ash, grade I, SiO2 content ≥55%, Al2O3 content ≥18%, Fe content ≤1%, S content ≤1%.

[0023] Quartz sand, natural sand, with SiO2 content ≥75%, mud content ≤3%, and average particle size of 180-200 mesh.

[0024] Cement, ordinary Portland cement with strength grade of 42.5MPa, Xinjiang Tianshan Cement Co., Ltd.

[0025] Quicklime, digestion time 8~14min, digestion temperature ≤90℃, effective CaO content ≥75%, 80μm square hole sieve residue ≤12.0%, Toksun County Jinlong Building Materials Co., Ltd.

[0026] The gypsum is desulfurized gypsum with a CaSO4 content of ≥90%.

[0027] Aluminum paste, active aluminum content ≥ 65%, 0.75mm sieve residue ≤ 2.5%, and 30min gas evolution rate ≥ 98%, Jinan Yuntian Aluminum Products Co., Ltd.

[0028] Example 1 A self-insulating autoclaved aerated concrete building block comprises aggregate and water. The aggregate comprises, by weight, 70 parts of fly ash, 10 parts of cement, 10 parts of quicklime, 1 part of gypsum, 0.07 parts of aluminum paste, and 2 parts of a special self-insulating admixture, and the slurry water-to-material ratio is 0.46.

[0029] The composition of the special self-insulation admixture is as follows: water reducing agent: air entraining agent: foam stabilizer: water repellent: surfactant: nano whisker in a ratio of 2:1:0.5:3:1:5.

[0030] A method for preparing an autoclaved aerated concrete self-insulating building block comprises the following steps: S1. 70 parts of fly ash, 1 part of gypsum and water are made into slurry with a diffusion of 360mm, put into a mixer, and then 2 parts of self-insulation special admixture, 10 parts of cement and 10 parts of quicklime are added in sequence, stirred for 3 minutes, and the diffusion is 190mm. Among them, the slurry water-to-material ratio is 0.46, and the pouring temperature is controlled at 39°C; S2. Add 0.07 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 seconds to obtain a finished slurry; S3. The finished slurry obtained in step S2 is poured into a mold and placed in a pre-curing chamber at 45°C for 150 minutes to form a volume-stable autoclaved aerated concrete semi-finished product; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. The semi-finished autoclaved aerated concrete obtained in step S4 is put into an autoclave for curing, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 minutes, and an artificial sewage discharge is performed; the constant temperature pressure is 1 MPa, the temperature is 175°C, the constant temperature time is 8 hours, and the sewage is discharged every 1 hour; the pressure is released for 1.5 hours, the temperature drops to below 80°C, and the single-side autoclave door is opened to obtain autoclaved aerated concrete self-insulating blocks.

[0031] Example 2 A self-insulating autoclaved aerated concrete building block comprises aggregate and water. The aggregate comprises, by weight, 65 parts of fly ash, 10 parts of cement, 15 parts of quicklime, 1 part of gypsum, 0.07 parts of aluminum paste and 2 parts of a special self-insulating admixture, and the slurry water-to-material ratio is 0.46.

[0032] The composition of the special self-insulation admixture is as follows: water reducing agent: air entraining agent: foam stabilizer: water repellent: surfactant: nano whisker in a ratio of 2:1:0.5:3:1:5.

[0033] A method for preparing an autoclaved aerated concrete self-insulating building block comprises the following steps: S1. 65 parts of fly ash, 1 part of gypsum and water are made into slurry with a diffusion of 360mm, put into a mixer, and then add 2 parts of self-insulation special admixture, 10 parts of cement, and 15 parts of quicklime in sequence, stir for 3 minutes, and the diffusion is 180mm. Among them, the slurry water-to-material ratio is 0.46, and the pouring temperature is controlled at 37°C; S2. Add 0.07 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 seconds to obtain a finished slurry; S3. The finished slurry obtained in step S2 is poured into a mold and placed in a pre-curing chamber at 45°C for 150 minutes to form a volume-stable autoclaved aerated concrete semi-finished product; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. The semi-finished autoclaved aerated concrete obtained in step S4 is put into an autoclave for curing, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 minutes, and an artificial sewage discharge is performed; the constant temperature pressure is 1 MPa, the temperature is 175°C, the constant temperature time is 8 hours, and the sewage is discharged every 1 hour; the pressure is released for 1.5 hours, the temperature drops to below 80°C, and the single-side autoclave door is opened to obtain autoclaved aerated concrete self-insulating blocks.

[0034] Example 3 A self-insulating autoclaved aerated concrete building block comprises aggregate and water. The aggregate comprises, by weight, 65 parts of fly ash, 15 parts of cement, 10 parts of quicklime, 1 part of gypsum, 0.07 parts of aluminum paste and 2.5 parts of a special self-insulating admixture, and the slurry water-to-material ratio is 0.46.

[0035] The composition of the special self-insulation admixture is as follows: water reducing agent: air entraining agent: foam stabilizer: water repellent: surfactant: nano whisker in a ratio of 2:1:0.5:3:1:5.

[0036] A method for preparing an autoclaved aerated concrete self-insulating building block comprises the following steps: S1. 65 parts of fly ash, 1 part of gypsum and water are made into slurry with a diffusion of 360mm, put into a mixer, and then 2.5 parts of self-insulation special admixture, 15 parts of cement, and 10 parts of quicklime are added in sequence, stirred for 3 minutes, and the diffusion is 180mm. Among them, the slurry water-to-material ratio is 0.46, and the pouring temperature is controlled at 39°C; S2. Add 0.07 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 seconds to obtain a finished slurry; S3. The finished slurry obtained in step S2 is poured into a mold and placed in a pre-curing chamber at 45°C for 150 minutes to form a volume-stable autoclaved aerated concrete semi-finished product; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. The semi-finished autoclaved aerated concrete obtained in step S4 is put into an autoclave for curing, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 minutes, and an artificial sewage discharge is performed; the constant temperature pressure is 1.1 MPa, the temperature is 182°C, the constant temperature time is 10 hours, and the sewage is discharged every 1 hour; the pressure relief time is 1.5 hours, the temperature drops to below 80°C, and the single-side autoclave door is opened to obtain autoclaved aerated concrete self-insulating blocks.

[0037] Comparative Example 1 An autoclaved aerated concrete self-insulating building block includes aggregate and water, wherein the aggregate includes 67 parts of fly ash, 10 parts of cement, 15 parts of quicklime, 1 part of gypsum, and 0.07 parts of aluminum paste by weight, and the slurry water-to-material ratio is 0.46. Since no admixture is added in this embodiment, in order to ensure that the bulk density remains unchanged, the fly ash is increased by 2 parts, and 67 parts of fly ash are used.

[0038] A method for preparing an autoclaved aerated concrete self-insulating building block comprises the following steps: S1. 67 parts of fly ash and 1 part of gypsum are made into slurry with a diffusion of 360mm, put into a mixer, and then 0 parts of self-insulation special admixture, 10 parts of cement, and 15 parts of quicklime are added in sequence, stirred for 3 minutes, and the diffusion is 180mm. Among them, the slurry water-to-material ratio is 0.46, and the pouring temperature is controlled at 37°C; S2. Add 0.07 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 seconds to obtain a finished slurry; S3. The finished slurry obtained in step S2 is poured into a mold and placed in a pre-curing chamber at 45°C for 150 minutes to form a volume-stable autoclaved aerated concrete semi-finished product; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. The semi-finished autoclaved aerated concrete obtained in step S4 is put into an autoclave for curing, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 min, and an artificial sewage discharge is performed; the constant temperature pressure is 1 MPa, the temperature is 175°C, the constant temperature time is 8 h, and the sewage is discharged once every 1 h; the pressure relief time is 1.5 h, the temperature drops to below 80°C, and the single-side autoclave door is opened to obtain autoclaved aerated concrete self-insulating blocks.

[0039] Test Example 1 The compressive strength shall be sampled and tested in accordance with GB / T 11969-2020.

[0040] The thermal conductivity is sampled and tested according to GB / T 10294.

[0041] The dry density shall be sampled and tested in accordance with GB / T 11969-2020.

[0042] Table 1 It can be seen from Table 1 that after adding the special self-insulation admixture, the strength grade of the autoclaved aerated concrete self-insulating block increased by about 20% compared with the comparative example 1, and the thermal conductivity of the autoclaved aerated concrete self-insulating block decreased by about 28%, and the comprehensive performance was significantly improved. The compressive strength reached the requirements of A5.0, and the thermal conductivity reached the requirements of B04 in the GB / T 11968-2020 standard, meeting the technical requirements of self-supporting and self-insulating blocks.

[0043] Example 4 A self-insulating autoclaved aerated concrete building block comprises aggregate and water. The aggregate comprises, by weight, 70 parts of natural sand, 12 parts of cement, 12 parts of quicklime and 2 parts of a special self-insulating admixture, and the slurry water-to-material ratio is 0.49.

[0044] The composition of the special self-insulation admixture is as follows: water reducing agent: air entraining agent: foam stabilizer: water repellent: surfactant: nano whisker in a ratio of 3:1:1:4:2:4.

[0045] A method for preparing an autoclaved aerated concrete self-insulating building block comprises the following steps: S1. Grind 70 parts of natural sand into slurry with a diffusion of 380 mm, put it into a mixer, and then add 2 parts of self-insulation special admixture, 12 parts of cement, 12 parts of quicklime, and 0.06 parts of aluminum paste in sequence, stir for 3 minutes, and the diffusion is 220 mm. Among them, the water-to-material ratio of the slurry is 0.49, and the pouring temperature is controlled at 39 ° C; S2. Add 0.06 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 seconds to obtain a finished slurry; S3: pouring the finished slurry obtained in step S2 into a mold box, and placing it in a pre-curing room at 45° C. for 150 minutes to form a semi-finished autoclaved aerated concrete product with stable volume; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. The semi-finished autoclaved aerated concrete obtained in step S4 is put into an autoclave for curing, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 min, and an artificial sewage discharge is performed; the constant temperature pressure is 1 MPa, the temperature is 175°C, the constant temperature time is 8 h, and the sewage is discharged once every 1 h; the pressure relief time is 1.5 h, the temperature drops to below 80°C, and the single-side autoclave door is opened to obtain autoclaved aerated concrete self-insulating blocks.

[0046] Example 5 A self-insulating autoclaved aerated concrete building block comprises aggregate and water. The aggregate comprises, by weight, 65 parts of natural sand, 10 parts of cement, 15 parts of quicklime, 1 part of gypsum, 0.07 parts of aluminum paste and 2 parts of a special self-insulating admixture, and the slurry water-to-material ratio is 0.47.

[0047] The composition of the special self-insulation admixture is as follows: water reducing agent: air entraining agent: foam stabilizer: water repellent: surfactant: nano whisker in a ratio of 3:1:1:4:2:4.

[0048] A method for preparing an autoclaved aerated concrete self-insulating building block comprises the following steps: S1. Grind 65 parts of natural sand and 1 part of gypsum into a slurry with a diffusion of 360mm, put it into a mixer, and then add 2 parts of sand aerated self-insulation special admixture, 10 parts of cement, and 15 parts of quicklime in sequence, stir for 3 minutes, and the diffusion is 200mm. Among them, the water-to-material ratio of the slurry is 0.47, and the pouring temperature is controlled at 37°C; S2. Add 0.07 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 seconds to obtain a finished slurry; S3. The finished slurry obtained in step S2 is poured into a mold and placed in a pre-curing chamber at 45°C for 150 minutes to form a volume-stable autoclaved aerated concrete semi-finished product; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. The semi-finished autoclaved aerated concrete obtained in step S4 is put into an autoclave for curing, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 min, and an artificial sewage discharge is performed; the constant temperature pressure is 1 MPa, the temperature is 175°C, the constant temperature time is 8 h, and the sewage is discharged once every 1 h; the pressure relief time is 1.5 h, the temperature drops to below 80°C, and the single-side autoclave door is opened to obtain autoclaved aerated concrete self-insulating blocks.

[0049] Example 6 A self-insulating autoclaved aerated concrete building block comprises aggregate and water. The aggregate comprises, by weight, 60 parts of natural sand, 15 parts of cement, 12 parts of quicklime, 0.075 parts of aluminum paste, and 2.5 parts of a special self-insulating admixture. The water-to-material ratio of the slurry is 0.46.

[0050] The composition of the special self-insulation admixture is as follows: water reducing agent: air entraining agent: foam stabilizer: water repellent: surfactant: nano whisker in a ratio of 3:1:1:4:2:4.

[0051] A method for preparing an autoclaved aerated concrete self-insulating building block comprises the following steps: S1. 60 parts of natural sand are ground into slurry with a diffusion of 360 mm, put into a mixer, and then 2.5 parts of self-insulation special admixture, 15 parts of cement, and 12 parts of quicklime are added in sequence, stirred for 3 minutes, and the diffusion is 180 mm. Among them, the slurry water-to-material ratio is 0.46, and the pouring temperature is controlled at 38 ° C; S2. Add 0.075 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 seconds to obtain a finished slurry; S3. The finished slurry obtained in step S2 is poured into a mold and placed in a pre-curing chamber at 45°C for 150 minutes to form a volume-stable autoclaved aerated concrete semi-finished product; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. The semi-finished autoclaved aerated concrete obtained in step S4 is put into an autoclave for curing, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 min, and an artificial sewage discharge is performed; the constant temperature pressure is 1.1 MPa, the temperature is 182°C, the constant temperature time is 10 h, and the sewage is discharged once every 1 h; the pressure relief time is 1.5 h, the temperature drops to below 80°C, and the single-side autoclave door is opened to obtain autoclaved aerated concrete self-insulating blocks.

[0052] Comparative Example 2 The autoclaved aerated concrete block comprises aggregate and water. The aggregate comprises, by weight, 67 parts of natural sand, 10 parts of cement, 15 parts of quicklime, 1 part of gypsum, and 0.07 parts of aluminum paste. The water-to-material ratio of the slurry is 0.46.

[0053] The method for preparing autoclaved aerated concrete blocks comprises the following steps: S1. 67 parts of natural sand and 1 part of gypsum are ground into slurry with a diffusion of 360mm, put into a mixer, and then 0 parts of self-insulation special admixture, 10 parts of cement, and 15 parts of quicklime are added in sequence, stirred for 3 minutes, and the diffusion is 200mm. Among them, the water-to-material ratio of the slurry is 0.46, and the pouring temperature is controlled at 37°C; S2. Add 0.07 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 seconds to obtain a finished slurry; S3. The finished slurry obtained in step S2 is poured into a mold and placed in a pre-curing chamber at 45°C for 150 minutes to form a volume-stable autoclaved aerated concrete semi-finished product; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. The semi-finished autoclaved aerated concrete obtained in step S4 is put into an autoclave for curing, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 minutes, and an artificial sewage discharge is performed; the constant temperature pressure is 1 MPa, the temperature is 175°C, the constant temperature time is 8 hours, and the sewage is discharged every 1 hour; the pressure is released for 1.5 hours, the temperature drops to below 80°C, and the single-side autoclave door is opened to obtain an autoclaved aerated concrete block.

[0054] Test Example 2 The compressive strength shall be sampled and tested in accordance with GB / T 11969-2020.

[0055] The thermal conductivity is sampled and tested according to GB / T 10294.

[0056] The dry density shall be sampled and tested in accordance with GB / T 11969-2020.

[0057] Table 2 As can be seen from Table 2, after adding the special admixture for sand aerated self-insulation, the strength grade of the autoclaved aerated concrete self-insulating block increased by about 35% compared with the control group, and the thermal conductivity of the autoclaved aerated concrete self-insulating block decreased by about 25%, and the comprehensive performance was significantly improved. The compressive strength reached the requirements of A5.0, and the thermal conductivity reached the requirements of B04 in the GB / T 11968-2020 standard, meeting the technical requirements of self-supporting and self-insulating blocks.

[0058] With the above-mentioned ideal embodiments of the present invention as inspiration, through the above-mentioned description, those skilled in the art can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the claims and the scope of the specification.

Claims

1. An autoclaved aerated concrete self-insulating building block, characterized in that: The invention comprises aggregate and water, and the water-to-material ratio is 0.4-0.6; the aggregate comprises, by weight, 50-80 parts of fly ash or quartz sand, 4-20 parts of cement, 5-20 parts of quicklime, 0-5 parts of gypsum, 0.05-0.15 parts of aluminum paste and 2-3 parts of special self-insulation admixture, and the special self-insulation admixture comprises a water reducer, an air entraining agent, a foam stabilizer, a hydrophobic agent, a surfactant and a nano whisker in a weight ratio of (1-3): 1: (0.5-1): (1-5): (0.5-2): (2-5).

2. The autoclaved aerated concrete self-insulating building block according to claim 1, characterized in that: It includes aggregate and water, and the water-to-aggregate ratio is 0.45-0.6; the aggregate includes 60-80 parts of fly ash, 10-20 parts of cement, 10-20 parts of quicklime, 0-5 parts of gypsum, 0.05-0.15 parts of aluminum paste and 2-3 parts of special self-insulation admixture in parts by mass.

3. The autoclaved aerated concrete self-insulating building block according to claim 1, characterized in that: It includes aggregate and water, and the water-to-material ratio is 0.4-0.55; the aggregate includes 50-75 parts of quartz sand, 10-20 parts of cement, 10-20 parts of quicklime, 0-3 parts of gypsum, 0.05-0.15 parts of aluminum paste and 2-3 parts of special self-insulation admixture in parts by mass.

4. The autoclaved aerated concrete self-insulating building block according to claim 1 or 2, characterized in that: The fly ash is Class I fly ash, wherein the SiO2 content is ≥55%, the Al2O3 content is ≥18%, the Fe content is ≤1%, and the S content is ≤1%.

5. The autoclaved aerated concrete self-insulating building block according to claim 1 or 3, characterized in that: The quartz sand is natural sand or aeolian sand, wherein the SiO2 content is ≥75%, the mud content is ≤3%, and the average particle size is 180-200 meshes.

6. The autoclaved aerated concrete self-insulating building block according to any one of claims 1 to 3, characterized in that: The cement is ordinary Portland cement with a strength grade of 42.5MPa; the quicklime digestion time is 8-14min, the digestion temperature is ≤90°C, the effective CaO content is ≥75%, and the 80μm square hole sieve residue is ≤12.0%; the active aluminum content in the aluminum paste is ≥65%, the 0.75mm sieve residue is ≤2.5%, and the 30min gas evolution rate is ≥98%; the gypsum is desulfurized gypsum, and the CaSO4 content is ≥90%.

7. The autoclaved aerated concrete self-insulating building block according to claim 1, characterized in that: The water reducer is one of naphthalene-based high-efficiency water reducer, polycarboxylic acid-based high-efficiency water reducer, aliphatic high-efficiency water reducer, and humate-based water reducer; The air entraining agent is one or more of rosin soap, rosin thermal polymer, sodium alkylbenzene sulfonate, sodium alkyl sulfate, fatty alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene sulfonate sodium, triterpenoid saponin, and modified lignin sulfonate; The foam stabilizer is one or more of polyacrylate, polyvinyl alcohol, polyoxyethylene alcohol, gelatin, gum arabic, polydimethylsiloxane, modified silicone oil, and aluminum sulfate; The water repellent is one or more of methyl trimethylsiloxane, polydimethylsiloxane, silicone acrylic emulsion, silicone resin emulsion, waterborne polyurethane emulsion, epoxy resin emulsion, calcium stearate, aluminum sulfate, aluminum chloride, zinc chloride, zinc sulfate, paraffin, and microcrystalline wax; The surfactant is one or more of sodium fatty acid, sodium laurate, sodium dodecyl sulfate, sodium alkylbenzene sulfonate, cocamidopropyl betaine, cocamidopropyl hydroxysulfobetaine, polyoxyethylene ether, sulfate ester salt, sulfonate, quaternary ammonium salt, polyoxyethylene-polyoxypropylene block copolymer; The nano whiskers are one or more of aluminum oxide nano whiskers, calcium phosphate nano whiskers, calcium silicate nano whiskers, calcium carbonate nano whiskers, calcium zeolite whiskers, sodium zeolite whiskers, and fumed silicon dioxide.

8. A method for preparing an autoclaved aerated concrete self-insulating building block, characterized in that: The following steps are involved: S1. Make a slurry of 50-80 parts of fly ash, 0-5 parts of gypsum and water, or make a slurry of 50-80 parts of quartz sand, 0-5 parts of gypsum and water, control the diffusion degree to 290-380 mm, put it into a mixer, and then add 2-3 parts of self-insulation special admixture, 4-20 parts of cement, and 5-20 parts of quicklime in sequence, stir for 3-5 minutes, control the diffusion degree to 150-220 mm, wherein the slurry water-to-material ratio is 0.4-0.6, and the pouring temperature is controlled at 37-42 ° C to obtain slurry; S2. Add 0.05 to 0.15 parts of aluminum paste to the slurry obtained in step S1 and stir for 30 to 45 seconds to obtain a finished slurry; S3. The finished slurry obtained in step S2 is poured into a mold and placed in a pre-curing chamber at 45°C for 120 to 180 minutes to form a volume-stable autoclaved aerated concrete semi-finished product; S4. The semi-finished autoclaved aerated concrete obtained in step S3 is cut and peeled according to size; S5. Put the semi-finished autoclaved aerated concrete obtained in step S4 into an autoclave for steaming to obtain autoclaved aerated concrete self-insulating building blocks.

9. The method for preparing an autoclaved aerated concrete self-insulating building block according to claim 8, characterized in that: In step S5, steam is introduced for curing, the pressure is increased from 0 to 0.5 MPa for 30 minutes, and sewage is discharged once; the constant temperature pressure is 0.9-1.2 MPa, the temperature is 175-192° C., the time is 6-12 hours, and sewage is discharged once every 1 hour; the pressure is released for 1.5-2 hours, the temperature drops to below 80° C., and a single-side kettle door is opened to obtain autoclaved aerated concrete self-insulating blocks.

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